SiRNA for inhibiting expression of SMAD family member 3, conjugate, pharmaceutical composition and application thereof

Abstract

The present invention relates to siRNA for inhibiting the expression of a SMAD family member 3 (SMAD3) gene, a siRNA conjugate, a pharmaceutical composition comprising the same, and uses thereof. Each nucleotide in the siRNA is independently modified or unmodified nucleotide, and the siRNA contains a positive-sense strand and an antisense strand. The siRNA as well as the conjugate and the pharmaceutical composition thereof can be used for effectively treating and / or preventing diseases related to SMAD3 gene overexpression.

Description

Technical Field

[0001] The present application relates to siRNA, siRNA conjugates, pharmaceutical compositions containing the siRNAs, preparation methods and uses thereof for inhibiting the expression of SMAD family member 3 genes. Background Art

[0002] Liver disease is a leading cause of death and disability worldwide. Chronic disease progressively impairs liver cell regeneration and even destroys liver cells, leading to liver fibrosis and cirrhosis. Liver disease or liver fibrosis is the result of viral or other infections, autoimmune diseases, bile duct obstruction, metabolic disorders, alcohol abuse, primary biliary cirrhosis, non-alcoholic steatohepatitis (NASH), exposure to chemicals or cancer. Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world, and its prevalence has doubled in the past 20 years, and it is now estimated to affect approximately 20-30% of the world's population. There are multiple pathological factors that cause non-alcoholic fatty liver disease. In some individuals, the accumulation of ectopic fat in the liver (steatosis) triggers inflammation and hepatocellular damage, leading to the further disease - non-alcoholic steatohepatitis (NASH). NASH is defined as lipid accumulation with cell damage, inflammation and varying degrees of scarring or fibrosis.

[0003] In studies of Drosophila melanogaster and Caenorhabditis elegans, it was found that Mad and Sma proteins act downstream of serine / threonine kinase receptors, so Mad and Sma proteins and their analogs are collectively referred to as SMAD (Sma-Mad) family proteins. Receptor-regulated SMAD (R-SMAD) is an intracellular signal transduction and transcription regulator activated by transforming growth factor TGFβ and activin type 1 receptor kinase. The use of mice with targeted deletion of SMAD3 (one of the two homologous proteins of TGF-b / activin) showed that SMAD3 mediates most of the pro-fibrotic activity of TGFβ. TGFβ plays an important role in fibrosis, promoting the influx and activation of inflammatory cells, epithelial-mesenchymal transition (EMT) of cells, the influx of fibroblasts and their subsequent removal of extracellular matrix. Experimental studies have shown that SMAD3-deficient mice are resistant to radiation-induced skin fibrosis, bleomycin-induced lung fibrosis, carbon tetrachloride-induced liver fibrosis, and streptozotocin-induced type 1 diabetes-induced glomerular fibrosis. SMAD3-deficient mice also show profibrotic responses in fibrotic diseases induced by EMT, such as proliferative vitreoretinopathy, eye cyst injury, and glomerular sclerosis caused by unilateral ureteral obstruction. Animal models of scleroderma, cystic fibrosis, and cirrhosis indicate that SMAD3 is involved in the observed fibrosis. By inhibiting the expression of SMAD3, the response of animal models of radiation-induced kidney, lung, and liver fibrosis was significantly reduced. Inhibiting the expression of SMAD3 protein present in the liver can inhibit diseases mediated by SMAD3 protein, such as autoimmune diseases, inflammation, tissue fibrosis, and tumors, such as liver fibrosis, glomerular sclerosis, and interstitial fibrosis. At the same time, studies have shown that SMAD3 protein can be used as a new target for ovarian cancer resistance to cisplatin.

[0004] In summary, by inhibiting the expression of SMAD3 gene in patients, non-alcoholic fatty liver disease, alcohol-related fatty liver disease, non-alcoholic fatty hepatitis, cirrhosis, liver fibrosis, pulmonary fibrosis, vascular fibrosis, glomerular sclerosis and interstitial fibrosis, and related cancers such as ovarian cancer can be prevented and treated. Currently, there are no drugs targeting only SMAD3 gene expression on the market, so the development of drugs targeting SMAD3 is of great value.

[0005] The present invention aims to provide siRNA, siRNA conjugates and pharmaceutical compositions thereof, which can selectively and effectively inhibit the expression of SMAD3 gene to achieve the purpose of disease treatment. Summary of the invention

[0006] The present invention provides an siRNA for inhibiting the expression of SMAD family member 3 (SMAD3) gene, wherein the siRNA comprises a sense strand and an antisense strand, wherein each nucleotide in the siRNA is independently a modified or unmodified nucleotide, wherein the sense strand comprises a nucleotide sequence I, and the antisense strand comprises a nucleotide sequence II, wherein the nucleotide sequence I and the nucleotide sequence II are at least partially reverse-complemented to form a double-stranded region, wherein the nucleotide sequence I and the nucleotide sequence II are selected from the following sequences:

[0007] (1) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 347, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 348:

[0008] 5'-AGCCUGGUCAAGAAACU-3'(SEQ ID NO:347)

[0009] 5'-AGUUUCUUGACCAGGCU-3' (SEQ ID NO:348);

[0010] (2) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 349, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 350:

[0011] 5'-CGUCAACACCAAGUG-3'(SEQ ID NO:349)

[0012] 5'-CACUUGGUGUUGACG-3' (SEQ ID NO:350);

[0013] (3) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 73, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 74:

[0014] 5'-ACACCAGUGCAUCACCAU-3'(SEQ ID NO:73)

[0015] 5'-AUGGUGAUGCACUUGGUGU-3' (SEQ ID NO:74);

[0016] (4) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 351, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 352:

[0017] 5'-GUGACCACCAGAUGA-3'(SEQ ID NO:351)

[0018] 5'-UCAUCUGGUGGUCAC-3' (SEQ ID NO: 352);

[0019] (5) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 353, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 354:

[0020] 5'-CGGAGACACAUCGGAA-3'(SEQ ID NO:353)

[0021] 5'-UUCCGAUGUGUCUCCG-3' (SEQ ID NO:354);

[0022] (6) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 355, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 356:

[0023] 5'-CGUGCGGCUCUACUA-3'(SEQ ID NO:355)

[0024] 5'-UAGUAGAGGCCGCACG-3' (SEQ ID NO: 356);

[0025] (7) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 357, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 358:

[0026] 5'-GUGACAGCGCUAU-3'(SEQ ID NO:357)

[0027] 5'-AUAGCGCUGUCAC-3' (SEQ ID NO: 358);

[0028] (8) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 359, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 360:

[0029] 5'-CAACUGUAACCAGCGCUA-3'(SEQ ID NO:359)

[0030] 5'-UAGCGCUGGUUACAGUUG-3' (SEQ ID NO:360);

[0031] (9) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 361, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 362:

[0032] 5'-ACCAGUUGACCCGAA-3'(SEQ ID NO:361)

[0033] 5'-UUCGGGUCAACUGGU-3' (SEQ ID NO:362);

[0034] (10) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 363, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 364:

[0035] 5'-GGAGUACAGGAGACAGA-3'(SEQ ID NO:363)

[0036] 5'-UCUGUCUCCUGUACUCC-3' (SEQ ID NO: 364);

[0037] wherein the nucleotide sequence I is not SEQ ID NO: 247, and the nucleotide sequence II is not SEQ ID NO: 248;

[0038] (11) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 365, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 366:

[0039] 5'-CUGGAUUGAGCUGCA-3'(SEQ ID NO:365)

[0040] 5'-UGCAGCUCAAUCCAG-3' (SEQ ID NO: 366);

[0041] (12) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 273, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 274:

[0042] 5'-GAUUGAGCUGCACCUGAAU-3'(SEQ ID NO:273)

[0043] 5'-AUUCAGGUGCAGCUCAAUC-3' (SEQ ID NO: 274);

[0044] (13) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 367, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 368:

[0045] 5'-CUGAAUGGGCCUUU-3'(SEQ ID NO:367)

[0046] 5'-AAAGGCCCAUUCAG-3' (SEQ ID NO:368);

[0047] (14) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 369, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 370:

[0048] 5'-CCAAGCAUCCGCUGUU-3'(SEQ ID NO:369)

[0049] 5'-AACAGCGGAUGCUUGG-3' (SEQ ID NO:370);

[0050] (15) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 371, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 372:

[0051] 5'-CGCUGUUCCAGUGUGU-3'(SEQ ID NO:371)

[0052] 5'-ACACACUGGAACAGCG-3' (SEQ ID NO: 372);

[0053] (16) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 373, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 374:

[0054] 5'-GUUCCAGUGUGUCUU-3'(SEQ ID NO:373)

[0055] 5'-AAGACACACUGGAAC-3' (SEQ ID NO: 374);

[0056] (17) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 375, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 376:

[0057] 5'-GGAGAAAUGGGCGAG-3'(SEQ ID NO:375)

[0058] 5'-CUCGCACCAUUUCUCC-3' (SEQ ID NO:376);

[0059] (18) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 377, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 378:

[0060] 5'-CAAGAGCCUGGUCA-3'(SEQ ID NO:377)

[0061] 5'-UGACCAGGCUCUUG-3' (SEQ ID NO:378);

[0062] (19) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 379, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 380:

[0063] 5'-CUACCUGAGUGAAGAU-3'(SEQ ID NO:379)

[0064] 5'-AUCUUCACUCAGGUAG-3' (SEQ ID NO:380);

[0065] (20) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 381, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 382:

[0066] 5'-GAGUGAAGAUGGAGAAA-3'(SEQ ID NO:381)

[0067] 5'-UUUCUCCAUCUUCACUC-3' (SEQ ID NO: 382);

[0068] (21) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 383, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 384:

[0069] 5'-GAGGAGAAAUGGUGCGA-3'(SEQ ID NO:383)

[0070] 5'-UCGCACCAUUUCUCCUC-3' (SEQ ID NO:384);

[0071] (22) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 81, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 82;

[0072] (23) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 83, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 84;

[0073] (24) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 85, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 86;

[0074] (25) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 118, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 119;

[0075] (26) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 153, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 154;

[0076] (27) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 155, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 156;

[0077] (28) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 219, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 220;

[0078] (29) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 340, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 341;

[0079] (30) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 524, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 525:

[0080] 5'-CCAGAUGAAC-3'(SEQ ID NO:524)

[0081] 5'-GUUCAUCUGG-3' (SEQ ID NO:525);

[0082] (31) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 526, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 527:

[0083] 5'-CAGCAUGGACGCAGGU-3'(SEQ ID NO:526)

[0084] 5'-ACCUGCGUCCAUGCCUG-3' (SEQ ID NO: 527);

[0085] (32) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 528, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 529:

[0086] 5'-CCAUCUCCUAC-3'(SEQ ID NO:528)

[0087] 5'-GUAGGAGAUGG-3' (SEQ ID NO: 529);

[0088] (33) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 530, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 531:

[0089] 5'-ACCUGAAGA-3'(SEQ ID NO:530)

[0090] 5'-UCUUCAGGU-3' (SEQ ID NO:531);

[0091] (34) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 532, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 533:

[0092] 5'-ACAAGGUCCUC-3'(SEQ ID NO:532)

[0093] 5'-GAGGACCUUGU-3' (SEQ ID NO:533);

[0094] (35) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 534, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 535:

[0095] 5'-CAUCCGCUGUUCCAGUG-3'(SEQ ID NO:534)

[0096] 5'-CACUGGAACAGCGGAUG-3' (SEQ ID NO: 535);

[0097] (36) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 520, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 521;

[0098] (37) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 393, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 394;

[0099] (38) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 395, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 396;

[0100] (39) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 397, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 398;

[0101] (40) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:407, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:408;

[0102] (41) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:427, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:428;

[0103] (42) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:437, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:438;

[0104] (43) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:441, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:442.

[0105] In one embodiment, the nucleotide sequence I and the nucleotide sequence II are substantially reverse complementary, essentially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there are no more than 3 base mismatches between the two nucleotide sequences; the substantially reverse complementary means that there are no more than 1 base mismatch between the two nucleotide sequences; and the completely reverse complementary means that there are no mismatches between the two nucleotide sequences.

[0106] In one embodiment, the sense strand further contains a nucleotide sequence III, and the antisense strand further contains a nucleotide sequence IV, and the lengths of the nucleotide sequence III and the nucleotide sequence IV are each independently 0-11 nucleotides, wherein the nucleotide sequence III is connected to the 5' end of the nucleotide sequence I, and the nucleotide sequence IV is connected to the 3' end of the nucleotide sequence II, and the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there is no more than one base mismatch between the two nucleotide sequences; and the completely reverse complementary means that there is no mismatch between the two nucleotide sequences; and / or, the nucleotide sequence III is connected to the 3' end of the nucleotide sequence I, and the nucleotide sequence IV is connected to the 5' end of the nucleotide sequence II, and the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there is no more than one base mismatch between the two nucleotide sequences; and the completely reverse complementary means that there is no mismatch between the two nucleotide sequences.

[0107] In one embodiment, the siRNA comprises a sense strand and an antisense strand, wherein each nucleotide in the siRNA is independently a modified or unmodified nucleotide, wherein the sense strand contains nucleotide sequences I and III, and the antisense strand contains nucleotide sequences II and IV, and the nucleotide sequences I and III are at least partially reverse complementary to the nucleotide sequences II and IV to form a double-stranded region, wherein the nucleotide sequences I and III, the nucleotide sequences II and IV are selected from the following sequences:

[0108] (1) The nucleotide sequences I and III comprise or consist of the nucleotide sequence shown in SEQ ID NO:465, and the nucleotide sequences II and IV comprise or consist of the nucleotide sequence shown in SEQ ID NO:466.

[0109] In one embodiment, the sense strand further contains a nucleotide sequence V and / or the antisense strand further contains a nucleotide sequence VI, the length of the nucleotide sequences V and VI is 0 to 3 nucleotides, the nucleotide sequence V is connected to the 3' end of the sense strand to form the 3' overhang of the sense strand, and / or the nucleotide sequence VI is connected to the 3' end of the antisense strand to form the 3' overhang of the antisense strand. In a preferred embodiment, the length of the nucleotide sequence V or VI is 2 nucleotides. In a preferred embodiment, the nucleotide sequence V or VI is two consecutive thymine deoxyribonucleotides or two consecutive uracil ribonucleotides. In a preferred embodiment, the nucleotide sequence V or VI is mismatched or complementary to the nucleotides at the corresponding position of the target mRNA.

[0110] In one embodiment, the length of the double-stranded region is 15-30 nucleotide pairs; preferably, the length of the double-stranded region is 17-23 nucleotide pairs; more preferably, the length of the double-stranded region is 19-21 nucleotide pairs.

[0111] In another embodiment, the sense strand or antisense strand has 15-30 nucleotides; preferably, the sense strand or antisense strand has 19-25 nucleotides; more preferably, the sense strand or antisense strand has 19-23 nucleotides. In one embodiment, at least one nucleotide in the sense strand or antisense strand is a modified nucleotide, and / or at least one phosphate group is a phosphate group with a modified group; preferably, the phosphate group with a modified group is a thiophosphate group formed by replacing one oxygen atom in the phosphodiester bond in the phosphate group with a sulfur atom.

[0112] In one embodiment, the siRNA comprises a sense strand that does not include a 3' overhang nucleotide.

[0113] In one embodiment, the 5' terminal nucleotide of the antisense strand is linked to a 5' phosphate group or a 5' phosphate-derivative group, or the 5' terminal nucleotide of the antisense strand is not linked to a 5' phosphate group or a 5' phosphate-derivative group.

[0114] In one embodiment, the modified nucleotides are selected from 2'-fluoro-modified nucleotides, 2'-alkoxy-modified nucleotides, 2'-substituted alkoxy-modified nucleotides, 2'-alkyl-modified nucleotides, 2'-substituted alkyl-modified nucleotides, 2'-deoxynucleotides, 2'-amino-modified nucleotides, 2'-substituted amino-modified nucleotides, nucleotide analogs or a combination of any two or more thereof.

[0115] In one embodiment, the modified nucleotides are selected from 2'-fluoro modified nucleotides, 2'-methoxy modified nucleotides, 2'-O-CH2-CH2-O-CH3 modified nucleotides, 2'-O-CH2-CH=CH2 modified nucleotides, 2'-CH2-CH2-CH=CH2 modified nucleotides, 2'-deoxy nucleotides, nucleotide analogs or a combination of any two or more thereof.

[0116] In one embodiment, each nucleotide in the sense strand and the antisense strand is independently a 2'-fluoro-modified nucleotide or a non-fluoro-modified nucleotide. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th and 14th positions of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 5, 7, 8 and 9 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 8, 9 and 10 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 3rd, 5th, 8th, 10th, 14th, 16th and 18th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 8th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 4th, 6th, 12th, 14th, 16th, 18th and 20th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th and 9th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 4th, 5th, 6th, 8th, 10th, 12th, 14th, 16th, 18th and 20th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 7 and 9 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 11th, 13th and 15th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th, 10th and 12th positions of the sense strand, and the remaining positions are non-fluoro modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 11th, 13th and 15th positions of the sense strand, and the remaining positions are non-fluoro modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 9th, 11th and 13th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 11th and 13th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 9th, 11th and 13th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 11th and 13th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 11th, 12th and 13th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 11th and 16th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 11th and 17th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 11th, 16th and 17th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 5th, 7th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides. In one embodiment, each non-fluorinated modified nucleotide is a 2'-methoxy modified nucleotide, and the 2'-methoxy modified nucleotide refers to a nucleotide formed by replacing the 2'-hydroxyl group of the ribose group with a methoxy group.

[0117] In one embodiment, each non-fluorinated modified nucleotide is independently selected from a nucleotide or a nucleotide analogue formed by replacing the hydroxyl group at the 2' position of the ribose group of the nucleotide with a non-fluorinated group, and the nucleotide analogue is selected from one of pseudouracil, isonucleotide, LNA, ENA, cET BNA, UNA and GNA.

[0118] In one embodiment, each nucleotide in the sense strand and the antisense strand is independently a 2'-fluoro-modified nucleotide, a 2'-methoxy-modified nucleotide, a GNA-modified nucleotide, a 2'-deoxyribonucleotide or a combination of any two or more thereof.

[0119] In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the GNA modified nucleotides are located at the 7th position of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 14th and 16th positions of the antisense strand, the GNA modified nucleotides are located at the 6th position of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6 and 14 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 5, 7, 8 and 9 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th and 10th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 5th, 8th, 10th, 14th, 16th and 18th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 4th, 6th, 12th, 14th, 16th, 18th and 20th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd and 14th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 7 and 9 of the sense strand, the 2'-deoxyribonucleotides are located at position 11 of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 4, 5, 6, 8, 10, 12, 14, 16, 18 and 20 of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th and 9th positions of the sense strand, the 2'-deoxyribonucleotides are located at the 11th position of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th, 13th and 15th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th, 10th and 12th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 9, 11, 13 and 15 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 9, 11 and 13 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, from 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 7, 9, 11 and 13 of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides; from 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 9th, 11th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th, 12th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th and 16th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 3, 7, 11 and 17 of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides.In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th, 16th and 17th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, the GNA modified nucleotides are located at the 6th position of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 5th, 7th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides. In a preferred embodiment, according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; according to the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides.

[0120] In some embodiments, at least one of the following linkages between nucleotides in the siRNA is a phosphorothioate linkage:

[0121] The connection between the first nucleotide and the second nucleotide starting from the 5' end of the sense strand;

[0122] The connection between the second nucleotide and the third nucleotide starting from the 5' end of the sense strand;

[0123] The connection between the first nucleotide and the second nucleotide starting from the 3' end of the sense strand;

[0124] The connection between the second nucleotide and the third nucleotide starting from the 3' end of the sense strand;

[0125] The ligation between the first nucleotide and the second nucleotide starting from the 5' end of the antisense strand;

[0126] The ligation between the second nucleotide and the third nucleotide starting from the 5' end of the antisense strand;

[0127] The connection between the first nucleotide and the second nucleotide starting from the 3' end of the antisense strand;

[0128] The linkage starts from the 2nd nucleotide and the 3rd nucleotide at the 3' end of the antisense strand.

[0129] In some embodiments, the siRNA, along the 5' end to the 3' end direction, the sense strand comprises a phosphorothioate group located at the following positions:

[0130] Between the first nucleotide and the second nucleotide starting from the 5' end of the sense strand;

[0131] Between the second nucleotide and the third nucleotide starting from the 5' end of the sense strand;

[0132] Between the first nucleotide and the second nucleotide starting from the 3' end of the sense strand;

[0133] Between the second nucleotide and the third nucleotide starting from the 3' end of the sense strand;

[0134] or,

[0135] The sense strand contains phosphorothioate groups located at the positions shown below:

[0136] Between the first nucleotide and the second nucleotide starting from the 5' end of the sense strand;

[0137] The positive strand is located between the second nucleotide and the third nucleotide starting from the 5' end.

[0138] In some embodiments, the antisense strand of the siRNA comprises a phosphorothioate group located at the following positions along the 5' end to the 3' end:

[0139] Between the first nucleotide and the second nucleotide starting from the 5' end of the antisense strand;

[0140] Between the second nucleotide and the third nucleotide starting from the 5' end of the antisense strand;

[0141] Between the first nucleotide and the second nucleotide starting from the 3' end of the antisense strand;

[0142] The antisense strand is located between the second nucleotide and the third nucleotide starting from the 3' end.

[0143] In one embodiment, each nucleotide in the sense strand and the antisense strand is independently a 2'-fluoro-modified nucleotide, a 2'-methoxy-modified nucleotide, a GNA-modified nucleotide, a 2'-deoxyribonucleotide or a combination of any two or more thereof.

[0144] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0145] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the 1st and 2nd nucleotides at the 5' end, the 2nd and 3rd nucleotides at the 5' end, the 1st and 2nd nucleotides at the 3' end, and the 2nd and 3rd nucleotides at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the 1st and 2nd nucleotides at the 5' end, the 2nd and 3rd nucleotides at the 5' end, the 1st and 2nd nucleotides at the 3' end, and the 2nd and 3rd nucleotides at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0146] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0147] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the 1st and 2nd nucleotides at the 5' end, the 2nd and 3rd nucleotides at the 5' end, the 1st and 2nd nucleotides at the 3' end, and the 2nd and 3rd nucleotides at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the 1st and 2nd nucleotides at the 5' end, the 2nd and 3rd nucleotides at the 5' end, the 1st and 2nd nucleotides at the 3' end, and the 2nd and 3rd nucleotides at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0148] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the GNA-modified nucleotide is located at the 7th position of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0149] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the GNA modified nucleotide is located at the 7th position of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0150] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 14th and 16th positions of the antisense strand, the GNA-modified nucleotide is located at the 6th position of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0151] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the 1st nucleotide and the 2nd nucleotide at the 5' end, the 2nd nucleotide and the 3rd nucleotide at the 5' end, the 1st nucleotide and the 2nd nucleotide at the 3' end, and the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 14th and 16th positions of the antisense strand, the GNA modified nucleotide is located at the 6th position of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the 1st nucleotide and the 2nd nucleotide at the 5' end, the 2nd nucleotide and the 3rd nucleotide at the 5' end, the 1st nucleotide and the 2nd nucleotide at the 3' end, and the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group.

[0152] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is not connected to a 5' phosphate group or a 5' phosphate derivative group.

[0153] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is not connected to a 5' phosphate group or a 5' phosphate derivative group.

[0154] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0155] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0156] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0157] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th and 14th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0158] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 5th, 7th, 8th and 9th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0159] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0160] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 8th, 9th and 10th positions of the sense strand, the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0161] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th and 10th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0162] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the 5' end between the first nucleotide and the second nucleotide, the 5' end between the second nucleotide and the third nucleotide, the 3' end between the first nucleotide and the second nucleotide, and the 3' end between the second nucleotide and the third nucleotide are connected by thiophosphate groups; in the 5' to 3' direction, the 2'- The fluorinated modified nucleotides are located at the 2nd, 3rd, 5th, 8th, 10th, 14th, 16th and 18th positions of the antisense chain, and the remaining positions are 2'-methoxy modified nucleotides. The 1st nucleotide and the 2nd nucleotide at the 5' end, the 2nd nucleotide and the 3rd nucleotide at the 5' end, the 1st nucleotide and the 2nd nucleotide at the 3' end, and the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense chain is connected to a 5'-trans vinyl phosphonate group.

[0163] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0164] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0165] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0166] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the 5' end between the first nucleotide and the second nucleotide, the 5' end between the second nucleotide and the third nucleotide, the 3' end between the first nucleotide and the second nucleotide, and the 3' end between the second nucleotide and the third nucleotide are connected by thiophosphate groups; in the 5' to 3' direction, the 2'- The fluorinated modified nucleotides are located at the 2nd, 4th, 6th, 12th, 14th, 16th, 18th and 20th positions of the antisense chain, and the remaining positions are 2'-methoxy modified nucleotides. The first and second nucleotides at the 5' end, the second and third nucleotides at the 5' end, the first and second nucleotides at the 3' end, and the second and third nucleotides at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense chain is connected to a 5'-trans vinyl phosphonate group.

[0167] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the 1st nucleotide and the 2nd nucleotide at the 5' end, the 2nd nucleotide and the 3rd nucleotide at the 5' end, the 1st nucleotide and the 2nd nucleotide at the 3' end, and the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd and 14th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the 1st nucleotide and the 2nd nucleotide at the 5' end, the 2nd nucleotide and the 3rd nucleotide at the 5' end, the 1st nucleotide and the 2nd nucleotide at the 3' end, and the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0168] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th and 9th positions of the sense strand, the 2'-deoxyribonucleotide is located at the 11th position of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are phosphorothioate-linked; in the 5' to 3' direction , 2'-fluoro modified nucleotides are located at the 2nd, 4th, 5th, 6th, 8th, 10th, 12th, 14th, 16th, 18th and 20th positions of the antisense chain, and the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense chain is connected to a 5'-trans vinyl phosphonate group.

[0169] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th and 9th positions of the sense strand, the 2'-deoxyribonucleotide is located at the 11th position of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are phosphorothioate-linked; In the 5' to 3' direction, 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense chain, and the remaining positions are 2'-methoxy modified nucleotides. Between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense chain is connected to a 5'-trans vinyl phosphonate group.

[0170] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th and 11th positions of the sense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0171] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0172] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th, 13th and 15th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0173] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th, 10th and 12th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0174] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 11th, 13th and 15th positions of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0175] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 11th, 13th and 15th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0176] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 9th, 11th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0177] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 11th and 13th positions of the sense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0178] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 11th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0179] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0180] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0181] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 9th, 11th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0182] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0183] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0184] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0185] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th, 12th and 13th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0186] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th and 16th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0187] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th and 17th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0188] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th, 16th and 17th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0189] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, the GNA modified nucleotide is located at the 6th position of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0190] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides. The 5' end between the first nucleotide and the second nucleotide, the 5' end between the second nucleotide and the third nucleotide, the 3' end between the first nucleotide and the second nucleotide, and the 3' end between the second nucleotide and the third nucleotide are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleoside The acid is located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense chain, the GNA-modified nucleotide is located at the 6th position of the antisense chain, the remaining positions are 2'-methoxy-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense chain is connected to a 5'-trans vinyl phosphonate group.

[0191] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0192] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 5th, 7th and 14th positions of the antisense strand, the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0193] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0194] In a preferred embodiment, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, and the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

[0195] In a specific embodiment, the present invention provides a siRNA selected from Table 1;Preferably, the siRNA is selected from N-ER-FY027167, N-ER-FY027167M2, N-ER-FY027167M3, N-ER-FY027167M6, N-ER-FY027167M7, N-ER-FY027167M8, N-ER-FY027167M8D2, N-ER-FY027167M9, N-ER-FY027186, N-ER-FY027186D2, N-ER-FY027186M2, N-ER-FY027186M3, N-ER-FY027186M4, N-ER-FY027186M5, N-ER-FY027186M6, N-ER-FY027186M7, N-ER-FY027186M8, N-ER-FY027186M8D2, N-ER-FY027186M9, N-ER-FY027186M10, N-ER-FY027186M11, N-ER-FY027186M12, N-ER-FY027186M13, N-ER-FY027186M13D2, N-ER-FY027186M14, N-ER-FY027186M15, N-ER-FY027186M15D2, N-ER-FY027186M16, N-ER-FY027186M17, N-ER-FY027186M18, N-ER-FY027186M19, N-ER-FY027186M20, N-ER-FY027186M21, N-ER-FY027186M21D2, N-ER-FY027186M22, N-ER-FY027186M23, N-ER-FY027186M24, N-ER-FY027186M24D2, N-ER-FY027186M25, N-ER-FY027186M26, N-ER-FY027186M26D2, N-ER-FY027186M27, N-ER-FY027186M27D2, N-ER-FY027186M28, N-ER-FY027186M29, N-ER-FY027186M29D2, N-ER-FY027186M30, N-ER-FY027186M31, N-ER-FY027186M32, N-ER-FY027186M33, N-ER-FY027186M34, N-ER-FY027186M35, N-ER-FY027186M35D2, N-ER-FY027186M37, N-ER-FY027186M40, N-ER-FY027186M44, N-ER-FY027186M45.;

[0196] The present invention also provides a siRNA conjugate, which contains the siRNA of the present invention and a conjugated group conjugated to the siRNA (as shown in the following diagram, a double helix structure represents the siRNA, and the conjugated group is connected to the 3' end of the sense strand of the siRNA):

[0197]

[0198] In the above conjugate structure, X can be selected as O or S. In one embodiment, X is O.

[0199] In one embodiment, the conjugate group comprises a pharmaceutically acceptable targeting group and a linker, and the siRNA, the linker and the targeting group are sequentially covalently or non-covalently linked.

[0200] Preferably, in the siRNA conjugate, the sense strand and the antisense strand of the siRNA are complementary to each other to form a double-stranded region of the siRNA conjugate, and the 3' end of the sense strand forms a blunt end, and the 3' end of the antisense strand has 1-3 protruding nucleotides extending out of the double-stranded region;

[0201] or,

[0202] In the siRNA conjugate, the sense strand and the antisense strand of the siRNA are complementary to each other to form a double-stranded region of the siRNA conjugate, and the 3' end of the sense strand forms a blunt end, while the 3' end of the antisense strand forms a blunt end.

[0203] In one embodiment, the conjugated group is selected from:

[0204]

[0205]

[0206]

[0207] In a specific embodiment, the siRNA conjugate is a siRNA conjugate selected from Table 2, preferably, the siRNA conjugate is selected from N-ER-FY027167M6L96, N-ER-FY027167M7L96, N-ER-FY027167M8L96, N-ER-FY027167M9L96, N-ER-FY027186M6L96, N-ER-FY027186M7L96, N-ER-FY027186M8L96, N-ER-FY027186M9L96. 96. N-ER-FY027186M10L96, N-ER-FY027186M11L96, N-ER-FY027186M12L96, N-ER-FY027186M13L96, N-ER-FY027186M14L 96. N-ER-FY027186M15L96, N-ER-FY027186M16L96, N-ER-FY027186M17L96, N-ER-FY027186M18L96, N-ER-FY027186M19L9 6. N-ER-FY027186M20L96, N-ER-FY027186M21L96, N-ER-FY027186M22L96, N-ER-FY027186M23L96, N-ER-FY027186M24L9 6. N-ER-FY027186M25L96, N-ER-FY027186M26L96, N-ER-FY027186M27L96, N-ER-FY027186M28L96, N-ER-FY027186M29L96 , N-ER-FY027186M30L96, N-ER-FY027186M31L96, N-ER-FY027186M32L96, N-ER-FY027186M33L96, N-ER-FY027186M34L96 , N-ER-FY027186M35L96, N-ER-FY027186M37L96, N-ER-FY027186M40L96, N-ER-FY027186M44L96, N-ER-FY027186M45L96.

[0208] The present invention also provides a pharmaceutical composition, which comprises the siRNA of the present invention, or the siRNA conjugate of the present invention, and a pharmaceutically acceptable carrier.

[0209] The present invention also provides a kit comprising the siRNA of the present invention, or the siRNA conjugate of the present invention, or the pharmaceutical composition of the present invention.

[0210] The present invention also provides use of the siRNA of the present invention, or the siRNA conjugate of the present invention, or the pharmaceutical composition of the present invention for preparing a medicament for inhibiting SMAD3 gene expression.

[0211] The present invention also provides use of the siRNA of the present invention, or the siRNA conjugate of the present invention, or the pharmaceutical composition of the present invention for preparing a medicament for preventing and / or treating diseases associated with SMAD3 gene overexpression.

[0212] In a specific embodiment, the disease is non-alcoholic fatty liver disease, alcohol-related fatty liver disease, non-alcoholic steatohepatitis, cirrhosis, liver fibrosis, pulmonary fibrosis, vascular fibrosis, glomerulosclerosis and interstitial fibrosis and cancer, in particular ovarian cancer.

[0213] The present invention also provides a method for inhibiting SMAD3 gene expression, comprising contacting a therapeutically effective amount of the siRNA of the present invention, or the siRNA conjugate of the present invention, or the pharmaceutical composition of the present invention with cells expressing SMAD3 or administering it to a subject in need thereof.

[0214] The present invention also provides a method for treating and / or preventing diseases related to SMAD3 gene overexpression, comprising administering a therapeutically effective amount of the siRNA of the present invention, or the siRNA conjugate of the present invention, or the pharmaceutical composition of the present invention to a subject in need.

[0215] In a specific embodiment, the disease is non-alcoholic fatty liver disease, alcohol-related fatty liver disease, non-alcoholic steatohepatitis, cirrhosis, liver fibrosis, pulmonary fibrosis, vascular fibrosis, glomerulosclerosis and interstitial fibrosis and cancer, in particular ovarian cancer.

[0216] Beneficial Effects

[0217] The siRNA, pharmaceutical composition and siRNA conjugate provided in the present application show excellent SMAD3 gene expression inhibition activity in in vitro cell experiments, and have good potential for treating diseases related to SMAD3 gene overexpression. For example, the siRNA and its conjugate disclosed in the present application can reduce the expression of SMAD3 mRNA in the liver, have low toxic side effects, good plasma stability, and have good clinical application prospects.

[0218] The siRNA provided in the present application shows a good inhibitory effect on the SMAD3 gene in HepG2 cells. In some specific embodiments, the siRNA of the present invention can significantly inhibit the expression of the SMAD3 gene at 10nM and 0.1nM, wherein the 48h inhibition rate at 10nM is as high as 65% or more, even as high as 75% or more, preferably as high as 85% or more, and the 48h inhibition rate at 0.1nM is as high as 50% or more, even as high as 70% or more, preferably as high as 80% or more.

[0219] In some embodiments, the siRNA provided in the present application has a higher SMAD3 gene inhibition activity in HepG2 cells, for example, IC 50 About 0.051-0.489nM, lowest to 0.051nM.

[0220] In some specific embodiments, the siRNA conjugates provided herein have high SMAD3 gene inhibitory activity in PHH cells. For example, under free uptake conditions, the inhibition rate at a concentration of 200 nM is as high as about 75% or more, and the inhibition rate at a concentration of 10 nM is as high as about 65% or more, or even as high as about 70% or more. DETAILED DESCRIPTION

[0221] definition

[0222] Throughout the specification, unless otherwise specified, in the technical field, "G", "C", "A", "T" and "U" generally represent the bases of guanine, cytosine, adenine, thymine and uracil, respectively, but it is also generally known in the art that "G", "C", "A", "T" and "U" each generally also represent nucleotides containing guanine, cytosine, adenine, thymine and uracil as bases, respectively, which is a common way to represent deoxyribonucleic acid sequences and / or ribonucleic acid sequences. Therefore, in the context of the present disclosure, the meanings represented by "G", "C", "A", "T" and "U" include the above-mentioned various possible situations; in this application, "nucleotide" and "ribonucleotide" can be used interchangeably. Lowercase letters a, u, c, g: indicate 2'-methoxy modified nucleotides; Af, Gf, Cf, Uf: indicate 2'-fluoro modified nucleotides; d: indicates that the nucleotide adjacent to the right of the letter d is a 2'-deoxyribonucleotide; lowercase letter s indicates that the two nucleotides adjacent to the left and right of the letter s are connected by thiophosphate groups; P1: indicates that the nucleotide adjacent to the right of P1 is a 5'-phosphate nucleotide; EVP: indicates that the nucleotide adjacent to the right of EVP is a 5'-trans-vinylphosphonate nucleotide; (Underline + Bold + Italic): indicates GNA-modified nucleotides.

[0223] In the above and below, the "2'-fluoro modified nucleotide" refers to a nucleotide in which the hydroxyl group at the 2' position of the ribose group of the nucleotide is replaced by fluorine. "Non-fluorinated modified nucleotide" refers to a nucleotide or nucleotide analog in which the hydroxyl group at the 2' position of the ribose group of the nucleotide is replaced by a non-fluorinated group. In some embodiments, each non-fluorinated modified nucleotide is independently selected from one of the nucleotides or nucleotide analogs in which the hydroxyl group at the 2' position of the ribose group of the nucleotide is replaced by a non-fluorinated group. The nucleotides in which the hydroxyl group at the 2' position of these ribose groups is replaced by a non-fluorinated group are well known to those skilled in the art, and these nucleotides can be selected from one of 2'-alkoxy modified nucleotides, 2'-substituted alkoxy modified nucleotides, 2'-alkyl modified nucleotides, 2'-substituted alkyl modified nucleotides, 2'-amino modified nucleotides, 2'-substituted amino modified nucleotides, and 2'-deoxy nucleotides.

[0224] "Alkyl" includes straight chain, branched chain or cyclic saturated alkyl. For example, alkyl includes but is not limited to methyl, ethyl, propyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, cyclohexyl and the like. Exemplary, "C 1-6 The "C" in "alkyl" 1-6 ” refers to a group containing 1, 2, 3, 4, 5 or 6 carbon atoms in a straight chain, branched chain or cyclic form.

[0225] "Alkoxy" refers herein to an alkyl group attached to the remainder of the molecule via an oxygen atom (-O-alkyl), wherein the alkyl group is as defined herein. Non-limiting examples of alkoxy include methoxy, ethoxy, trifluoromethoxy, difluoromethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, n-pentoxy, and the like.

[0226] "Nucleotide analogs" refer to groups that can replace nucleotides in nucleic acids but have structures different from adenine ribonucleotides, guanine ribonucleotides, cytosine ribonucleotides, uracil ribonucleotides or thymine deoxyribonucleotides, such as pseudouracil (Ψ), isonucleotides, bridged nucleic acids (BNA) or acyclic nucleotides.

[0227] Pseudouracil (Ψ) refers to a natural structural analog of uridine nucleoside, in which the ribose is not attached to the N1 of uracil, but to the C5 of the pyrimidine ring.

[0228]

[0229] BNA refers to a constrained or inaccessible nucleotide. BNA may contain a five-membered ring, a six-membered ring, or a seven-membered ring with a "fixed" C3'-endosugar condensed bridge structure. The bridge is usually incorporated into the 2'-, 4'-position of the ribose to provide a 2', 4'-BNA nucleotide, such as LNA, ENA, cET BNA, etc., wherein LNA is shown in formula (1), ENA is shown in formula (2), and cET BNA is shown in formula (3):

[0230]

[0231] Acyclic nucleotides are a type of nucleotides formed by opening the sugar ring of a nucleotide, such as unlocked nucleic acid (UNA) or glycerol nucleic acid (GNA), wherein UNA is shown in formula (4) and GNA is shown in formula (5):

[0232]

[0233] In the above formula (4) and formula (5), R is selected from H, OH or alkoxy (O-alkyl).

[0234] Isonucleotides refer to compounds formed by a change in the position of the base on the ribose ring of a nucleotide, for example, a compound formed by the base moving from the 1'-position to the 2'-position or the 3'-position of the ribose ring, as shown in formula (6) or (7):

[0235]

[0236] In the compounds of formula (6)-(7) above, Base represents a base, such as A, U, G, C or T; and R is selected from H, OH, F or the non-fluorine group as described above.

[0237] In some embodiments, the nucleotide analog is selected from one of pseudouracil, isonucleotide, LNA, ENA, cET BNA, UNA and GNA. In some embodiments, each non-fluorinated modified nucleotide is a 2'-methoxy modified nucleotide, a GNA modified nucleotide or a combination of any two or more thereof. In some preferred embodiments, each non-fluorinated modified nucleotide is a 2'-methoxy modified nucleotide. In the above and below, the 2'-methoxy modified nucleotide refers to a nucleotide formed by replacing the 2'-hydroxyl of the ribose group with a methoxy group.

[0238] The "2'-methoxy modified nucleotide" refers to a nucleotide in which the 2'-hydroxyl group of the ribose group is replaced by a methoxy group. The "phosphorothioate group" refers to a phosphorothioate group in which one oxygen atom in the phosphodiester bond of the phosphate group is replaced by a sulfur atom.

[0239] The "phosphorothioate group" refers to the following formula:

[0240]

[0241] The "5'-phosphate nucleotide" refers to the structure of the following formula:

[0242]

[0243] In the context of this specification, the expressions "complementary" and "reverse complementary" can be used interchangeably and have the meanings known to those skilled in the art, i.e., in a double-stranded nucleic acid molecule, the bases of one chain are each paired with the bases on the other chain in a complementary manner. In DNA, the purine base adenine (A) is always paired with the pyrimidine base thymine (T) (or uracil (U) in RNA); the purine base guanine (G) is always paired with the pyrimidine base cytosine (C). Each base pair includes a purine and a pyrimidine. When adenine on one chain is always paired with thymine (or uracil) on the other chain, and guanine is always paired with cytosine, the two chains are considered to be complementary to each other, and the sequence of the chain can be inferred from the sequence of its complementary chain. Correspondingly, "mismatch" means in the art that in a double-stranded nucleic acid, the bases at corresponding positions are not paired in a complementary form.

[0244] In the above and below, unless otherwise specified, "substantially reverse complementary" means that there are no more than 3 base mismatches between the two nucleotide sequences involved; "substantially reverse complementary" means that there are no more than 1 base mismatch between the two nucleotide sequences; and "completely reverse complementary" means that there are no base mismatches between the two nucleotide sequences.

[0245] In the above and below, "nucleotide difference" between one nucleotide sequence and another nucleotide sequence means that the base type of the nucleotide at the same position of the former is changed compared with the latter. For example, when a nucleotide base in the latter is A, and the corresponding nucleotide base at the same position of the former is U, C, G or T, it is considered that there is a nucleotide difference at that position between the two nucleotide sequences. In some embodiments, when a nucleotide at the original position is replaced by an abasic nucleotide or its equivalent, it can also be considered that a nucleotide difference occurs at that position.

[0246] In this context, "overhang" refers to one or more unpaired nucleotides that protrude from the duplex structure of the siRNA when a 3' end of one strand of the siRNA extends beyond the 5' end of the other strand, or vice versa. "Blunt end" or "blunt end" means that there are no unpaired nucleotides at that end of the siRNA, i.e., no nucleotide overhang. A "blunt-ended" siRNA is one that is double-stranded throughout its length, i.e., has no nucleotide overhangs at either end of the molecule.

[0247] In the above and below of the present specification, especially when describing the preparation method of the siRNA, pharmaceutical composition or siRNA conjugate of the present application, unless otherwise specified, the nucleoside monomer refers to the modified or unmodified nucleoside phosphoramidite monomer used in the solid phase phosphoramidite synthesis according to the type and order of nucleotides in the siRNA or siRNA conjugate to be prepared. Solid phase phosphoramidite synthesis is a method used in RNA synthesis known to those skilled in the art. The nucleoside monomers used in the present application are all commercially available.

[0248] In the context of the present application, unless otherwise specified, "conjugation" refers to the covalent connection between two or more chemical moieties each having a specific function; accordingly, "conjugate" refers to a compound formed by covalent connection between the chemical moieties. Further, "siRNA conjugate" means a compound formed by covalently connecting one or more chemical moieties having a specific function to siRNA. Depending on the context, siRNA conjugates should be understood as a general term for multiple siRNA conjugates or an siRNA conjugate shown by a certain chemical formula. In the context of the present application specification, "conjugated molecule" should be understood as a specific compound that can be conjugated to siRNA through a reaction to ultimately form the siRNA conjugate of the present application.

[0249] Various hydroxyl protecting groups can be used in the present application. In general, the protecting group makes the chemical functional group insensitive to specific reaction conditions, and can be attached and removed from the functional group in the molecule without substantially damaging the rest of the molecule. In some embodiments, the protecting group is stable under alkaline conditions, but can be removed under acidic conditions. In some embodiments, non-exclusive examples of hydroxyl protecting groups that can be used in the present application include monomethoxytrityl, 9-phenylxanthine-9-yl (Pixyl) and 9-(p-methoxyphenyl)xanthine-9-yl (Mox). In some embodiments, non-exclusive examples of hydroxyl protecting groups that can be used in the present application include Tr (trityl), MMTr (4-methoxytrityl), DMTr (4,4'-dimethoxytrityl) and TMTr (4,4',4"-trimethoxytrityl).

[0250] As used herein, "optional" or "optionally" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0251] The term "subject", as used in this specification, refers to any animal, such as a mammal or a marsupial. The subject of the present application includes, but is not limited to, humans, non-human primates (e.g., rhesus monkeys or other types of macaques), mice, pigs, horses, donkeys, cattle, sheep, rats, rabbits, or any kind of poultry.

[0252] As used herein, "treatment" refers to a method of obtaining a beneficial or desired result, including but not limited to a therapeutic benefit. "Therapeutic benefit" means eradication or amelioration of the underlying disorder being treated. In addition, a therapeutic benefit is obtained by eradication or amelioration of one or more physiological symptoms associated with the underlying disorder, thereby observing an improvement in the subject, although the subject may still be afflicted with the underlying disorder.

[0253] As used herein, "prevention" refers to an approach to obtaining beneficial or desired results, including but not limited to a prophylactic benefit. To obtain a "prophylactic benefit," siRNA, siRNA conjugates, or pharmaceutical compositions may be administered to a subject at risk for a particular disease, or to a subject reporting one or more physiological symptoms of a disease, even though a diagnosis of the disease may not have been made.

[0254] As used herein, "prodrug" refers to a compound that can be converted into an active compound by certain chemical or physiological processes (e.g., enzymatic processes and metabolic hydrolysis). Therefore, the term "prodrug" also refers to a precursor of a pharmaceutically acceptable biologically active compound.

[0255] In this article, considering the situation that the 5' terminal nucleotide of the antisense chain is connected to the 5' hydroxyl group (i.e., there is no phosphate group), such an antisense chain will first be phosphorylated in vivo to convert the 5' terminal nucleotide into a nucleotide carrying a 5' phosphate group, and then play a role in the body. Therefore, in the present invention, such siRNA, siRNA modifications, and siRNA conjugates are also referred to as prodrugs. For example, in this application, the siRNA modification or conjugate with M6 pattern modification is a prodrug of the siRNA modification or conjugate with M2 pattern modification, because the difference between M2 pattern modification and M6 pattern modification is whether there is P1 at the 5' end of the antisense chain. Similarly, the relationship between M7 pattern modification and M3 pattern modification is the same. Therefore, siRNA in this article includes its corresponding prodrug.

[0256] siRNA

[0257] The application relates to a siRNA that can inhibit SMAD3 gene expression. The siRNA of the present application contains a nucleotide group as a basic structural unit, and it is well known to those skilled in the art that the nucleotide group contains a phosphate group, a ribose group and a base. It is generally active, i.e., the length of functional siRNA is about 12-40 nucleotides, and in some embodiments is about 15-30 nucleotides.

[0258] The siRNA of the present application contains a sense strand and an antisense strand, and each nucleotide in the siRNA is independently a modified or unmodified nucleotide, wherein the sense strand contains a nucleotide sequence I, and the antisense strand contains a nucleotide sequence II, and the nucleotide sequence I and the nucleotide sequence II are at least partially reverse-complemented to form a double-stranded region. In some embodiments, the length of the double-stranded region is 15-30 nucleotide pairs. In other embodiments, the length of the double-stranded region is 17-23 nucleotide pairs. In other embodiments, the length of the double-stranded region is 19-21 nucleotide pairs. In yet other embodiments, the length of the double-stranded region is 19 or 21 nucleotide pairs.

[0259] In some embodiments, the sense strand further contains nucleotide sequence III, the antisense strand further contains nucleotide sequence IV, the length of nucleotide sequence III and nucleotide sequence IV is independently 0-11 nucleotides, the nucleotide sequence III is connected to the 5' end of nucleotide sequence I, the nucleotide sequence IV is connected to the 3' end of nucleotide sequence II, the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there is no more than 1 base mismatch between the two nucleotide sequences; the completely reverse complementary means that there is no mismatch between the two nucleotide sequences. In some embodiments, the sense strand further contains nucleotide sequence III, the antisense strand further contains nucleotide sequence IV, the length of nucleotide sequence III and nucleotide sequence IV is independently 0-11 nucleotides, the nucleotide sequence III is connected to the 3' end of nucleotide sequence I, the nucleotide sequence IV is connected to the 5' end of nucleotide sequence II, the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there is no more than 1 base mismatch between the two nucleotide sequences; the completely reverse complementary means that there is no mismatch between the two nucleotide sequences. In some embodiments, the sense strand further contains a nucleotide sequence III, and the antisense strand further contains a nucleotide sequence IV, the lengths of the nucleotide sequence III and the nucleotide sequence IV are each independently 0-11 nucleotides, the nucleotide sequence III is connected to the 5' end of the nucleotide sequence I, the nucleotide sequence IV is connected to the 3' end of the nucleotide sequence II, the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; and the nucleotide sequence III is connected to the 3' end of the nucleotide sequence I, the nucleotide sequence IV is connected to the 5' end of the nucleotide sequence II, the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there is no more than one base mismatch between the two nucleotide sequences; and completely reverse complementary means that there is no mismatch between the two nucleotide sequences.

[0260] In some embodiments, the sense strand further contains a nucleotide sequence V and / or the antisense strand further contains a nucleotide sequence VI, the length of the nucleotide sequences V and VI is 0 to 3 nucleotides, the nucleotide sequence V is connected to the 3' end of the sense strand to form the 3' overhang of the sense strand, and / or the nucleotide sequence VI is connected to the 3' end of the antisense strand to form the 3' overhang of the antisense strand. In some embodiments, the length of the nucleotide sequence V or VI is 2 nucleotides. In other embodiments, the nucleotide sequence V or VI is two consecutive thymine deoxyribonucleotides or two consecutive uracil ribonucleotides. In other embodiments, the nucleotide sequence V or VI is mismatched or complementary to the nucleotides at the corresponding positions of the target mRNA.

[0261] The lengths of the sense strand and antisense strand provided herein are the same or different. In some embodiments, the sense strand or antisense strand has 15-30 nucleotides. In other embodiments, the sense strand or antisense strand has 19-25 nucleotides. In other embodiments, the sense strand or antisense strand has 19-23 nucleotides. The length ratio of the sense strand and antisense strand of the siRNA provided herein can be 15 / 15, 16 / 16, 17 / 17, 18 / 18, 19 / 19, 19 / 20, 19 / 21, 19 / 22, 19 / 23, 20 / 19, 20 / 20, 20 / 21, 20 / 22, 20 / 23, 21 / 19, 21 / 20, 21 / 21, 21 / 22, 21 / 23, 22 / 19, 22 / 20, 22 / 21, 22 / 22, 22 / 23, 23 / 19, 23 / 20, 23 / 21, 23 / 22, 23 / 23, 24 / 24, 25 / 25, 26 / 26, 27 / 27, 28 / 28, 29 / 29, 30 / 30, 22 / 24, 22 / 25, 22 / 26, 23 / 24, 23 / 25 or 23 / 26, etc. In some embodiments, the length ratio of the siRNA sense strand to the antisense strand is 19 / 19, 21 / 21, 19 / 21, 21 / 23 or 23 / 23. At this time, the siRNA disclosed in the present invention has better cell mRNA silencing activity.

[0262] Studies have found that different modification strategies can have very different effects on siRNA stability, biological activity, cytotoxicity and other indicators. For example, CN102140458B studied various chemical modification strategies for siRNA and confirmed 7 effective modification methods. Compared with unmodified siRNA, one of the modified methods produced siRNA that improved blood stability while maintaining inhibitory activity that was basically equivalent to that of unmodified siRNA.

[0263] The nucleotides in the siRNA of the present invention are each independently a modified or unmodified nucleotide. In some embodiments, each nucleotide in the siRNA of the present invention is an unmodified nucleotide; in some embodiments, some or all of the nucleotides in the siRNA of the present invention are modified nucleotides, and these modifications on the nucleotide groups do not result in a significant weakening or loss of the function of the siRNA of the present invention in inhibiting the expression of the SMAD3 gene.

[0264] In some embodiments, the siRNA of the present application contains at least one modified nucleotide. In the context of the present application, the term "modified nucleotide" used refers to a nucleotide or nucleotide analog formed by replacing the 2' hydroxyl group of the ribose group of the nucleotide with other groups, or a nucleotide with a modified base. The modified nucleotide will not cause the function of the siRNA to inhibit gene expression to be significantly weakened or lost. For example, the modified nucleotide disclosed in JK Watts, GF Deleavey, and M.J. Damha, Chemically modified siRNA: tools and applications. Drug Discov Today, 2008, 13 (19-20): 842-55 can be selected.

[0265] In some embodiments, at least one nucleotide in the sense strand or the antisense strand of the siRNA provided by the present invention is a modified nucleotide, and / or at least one phosphate group is a phosphate group with a modified group; in other words, at least a portion of the phosphate group and / or ribose group in the phosphate-sugar backbone of at least one single strand of the sense strand and the antisense strand is a phosphate group with a modified group and / or a ribose group with a modified group. In some embodiments, the phosphate group with a modified group is a thiophosphate group formed by replacing one oxygen atom in the phosphodiester bond in the phosphate group with a sulfur atom.

[0266] In some embodiments, the siRNA includes a sense strand that does not include a 3' overhanging nucleotide; that is, the sense strand of the siRNA may have a 3' overhanging nucleotide, and the 3' overhanging nucleotide of the sense strand is excluded to form a blunt end. In some embodiments, the siRNA includes a modification in which the 3' end of the sense strand in Table 1 is modified to a blunt end, optionally obtained by excluding the overhang extending from the double-stranded region at the 3' end of the sense strand in Table 1.

[0267] In some embodiments, when the nucleotide sequences of the sense strand and the antisense strand complement each other to form a double-stranded region, if there is no protruding nucleotide at the 3' end of the sense strand, a nucleotide sequence V is added to the 3' end of the sense strand as a protruding nucleotide. Then, after the nucleotide sequence formed by connecting the nucleotide sequence V to the 3' end of the sense strand is chemically modified, the nucleotide sequence V is excluded, and accordingly, the sense strand of the siRNA forms a blunt end.

[0268] In some embodiments, when the nucleotide sequences of the sense strand and the antisense strand are complementary to form a double-stranded region, and the 3' end of the sense strand has protruding nucleotides extending out of the double-stranded region, the protruding nucleotides at the 3' end of the sense strand are excluded and used as the nucleotide sequence of the sense strand, and accordingly, the sense strand of the siRNA forms a blunt end.

[0269] In some embodiments, the 5' terminal nucleotide of the antisense strand is linked to a 5' phosphate group or a 5' phosphate-derived group.

[0270] An exemplary 5' phosphate group has the structure: The structures of the 5' phosphate derivative group include but are not limited to: wait.

[0271] The 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group or a 5' phosphate derivative group to form the following structure:

[0272]

[0273] Wherein, Base represents a base, such as A, U, G, C or T. R' is a hydroxyl group or is substituted by various groups known to those skilled in the art, for example, the substituted modified nucleotide can be a 2'-fluoro (2'-F) modified nucleotide, a 2'-alkoxy modified nucleotide, a 2'-substituted alkoxy modified nucleotide, a 2'-alkyl modified nucleotide, a 2'-substituted alkyl modified nucleotide, a 2'-amino modified nucleotide, a 2'-substituted amino modified nucleotide, or a 2'-deoxy nucleotide.

[0274] In some embodiments, the 5' terminal nucleotide of the sense strand or antisense strand is not connected to a 5' phosphate group or a 5' phosphate derivative group (ie, the ribose group of the 5' terminal nucleotide of the sense strand or antisense strand is a 5' hydroxyl group), and its structure is shown below:

[0275]

[0276] Wherein, Base represents a base, such as A, U, G, C or T. R is hydroxyl or hydrogen or is substituted by various groups known to those skilled in the art, for example, R can be 2'-fluoro (2'-F), 2'-alkoxy, 2'-substituted alkoxy, 2'-alkyl, 2'-substituted alkyl, 2'-amino, 2'-substituted amino.

[0277] Exemplary modified nucleotides have the following structures:

[0278]

[0279] Wherein, Base represents a base, such as A, U, G, C or T. The hydroxyl group at the 2' position of the ribose group is substituted by R. The hydroxyl group at the 2' position of these ribose groups can be substituted by various groups known to those skilled in the art, for example, the substituted modified nucleotides can be 2'-fluoro (2'-F) modified nucleotides, 2'-alkoxy modified nucleotides, 2'-substituted alkoxy modified nucleotides, 2'-alkyl modified nucleotides, 2'-substituted alkyl modified nucleotides, 2'-amino modified nucleotides, 2'-substituted amino modified nucleotides, 2'-deoxy nucleotides.

[0280] In some embodiments, the 2'-alkoxy modified nucleotide is a 2'-methoxy (2'-OMe, 2'-O-CH3) modified nucleotide, and the like.

[0281] In some embodiments, the 2'-substituted alkoxy modified nucleotide is a 2'-methoxyethoxy (2'-O-CH2-CH2-O-CH3) modified nucleotide, a 2'-O-CH2-CH=CH2 modified nucleotide, and the like.

[0282] In some embodiments, the 2'-substituted alkyl modified nucleotide is a 2'-CH2-CH2-CH=CH2 modified nucleotide and the like.

[0283] In some embodiments, all nucleotides in the sense strand and / or the antisense strand are modified nucleotides. In some embodiments, each nucleotide in the sense strand and the antisense strand of the siRNA provided by the present invention is independently a 2'-fluoro-modified nucleotide or a non-fluoro-modified nucleotide. In some embodiments, each non-fluoro-modified nucleotide is a 2'-methoxy-modified nucleotide, a GNA-modified nucleotide, a 2'-deoxyribonucleotide, or a combination of any two or more thereof, and the 2'-methoxy-modified nucleotide refers to a nucleotide formed by replacing the 2'-hydroxyl of the ribose group with a methoxy group.

[0284] siRNA conjugates

[0285] The present application relates to an siRNA conjugate, which contains the above-mentioned siRNA and a conjugation group conjugated to the siRNA.

[0286] In the present application, the sense strand and the antisense strand of the siRNA conjugate form a double-stranded region of the siRNA conjugate, and a blunt end is formed at the 3' end of the sense strand of the siRNA conjugate. In some embodiments, the 3' end of the sense strand of the siRNA conjugate forms a blunt end, and the 3' end of the antisense strand of the siRNA conjugate has 1-3 protruding nucleotides extending out of the double-stranded region. In other embodiments, the 3' end of the sense strand of the siRNA conjugate forms a blunt end, and the 3' end of the antisense strand of the siRNA conjugate forms a blunt end.

[0287] In some preferred embodiments, the siRNA conjugate is obtained by conjugating siRNA with a conjugating group, wherein the sense strand of the siRNA is complementary to the antisense strand to form a double-stranded region of the siRNA, and the 3' end of the sense strand of the siRNA forms a blunt end, and the conjugating group is conjugated with the 3' end of the sense strand having the blunt end to form the siRNA conjugate.

[0288] In some preferred embodiments, the 3' end of the sense strand of the siRNA has a protruding nucleotide extending out of the double-stranded region, and the sequence with a 3' blunt end formed after excluding the protruding nucleotides at the 3' end of the sense strand is used as the nucleotide sequence for connecting the conjugated group, and the conjugated group is connected to the 3' blunt end of the sense strand to form a siRNA conjugate.

[0289] In some more preferred embodiments, when the nucleotide sequences of the sense strand and the antisense strand complement each other to form a double-stranded region, if there is no protruding nucleotide at the 3' end of the sense strand, a nucleotide sequence V is added to the 3' end of the sense strand as a protruding nucleotide. The sequence with a 3' blunt end formed after the protruding nucleotide at the 3' end of the sense strand is excluded is used as a nucleotide sequence for connecting a conjugated group, and a conjugated group is connected to the 3' blunt end of the sense strand to form a siRNA conjugate.

[0290] In some more preferred embodiments, when the nucleotide sequences of the sense strand and the antisense strand are complementary to form a double-stranded region, and the 3' end of the sense strand has protruding nucleotides extending out of the double-stranded region, the sequence with a 3' blunt end formed after excluding the protruding nucleotides at the 3' end of the sense strand is used as the nucleotide sequence for connecting the conjugated group, and the conjugated group is connected to the 3' blunt end of the sense strand to form a siRNA conjugate.

[0291] For example, the siRNA sequence is as shown in N-ER-FY027001M3, the 3' end of the sense strand of the siRNA has a protruding nucleotide extending out of the double-stranded region, and the gsasggagAfaAfUfGfgugcgaga blunt-end sequence formed after excluding the protruding -sTsT nucleotide at the 3' end of the sense strand is used as the nucleotide sequence for connecting the L96 conjugation group. Therefore, the sequence of the siRNA conjugate is: the sense strand is

[0292] gsasggagAfaAfUfGfgugcgagaL96, the antisense strand is P1usCfsucgCfaCfCfauuuCfuCfcucsTsT.

[0293] In general, the conjugated group includes at least one pharmaceutically acceptable targeting group, or further includes a linker, and the siRNA, the linker and the targeting group are connected in sequence. In some embodiments, the targeting group is 1-6. In some embodiments, the targeting group is 2-4. The siRNA molecule can be non-covalently or covalently conjugated to the conjugated group, for example, it can be covalently conjugated to the conjugated group. The conjugation site of siRNA and conjugated group can be at the 3' end or 5' end of the siRNA sense strand, also at the 5' end of the antisense strand, and can also be in the internal sequence of siRNA. In some embodiments, the conjugation site of siRNA and conjugated group is at the 3' end of the siRNA sense strand.

[0294] In some embodiments, the conjugate group can be connected to the phosphate group, 2'-hydroxyl group or base of the nucleotide. In some embodiments, the conjugate group can also be connected to the 3'-hydroxyl group, in which case the nucleotides are connected by a 2'-5' phosphodiester bond. When the conjugate group is connected to the end of the siRNA chain, the conjugate group is usually connected to the phosphate group of the nucleotide; when the conjugate group is connected to the internal sequence of the siRNA, the conjugate group is usually connected to the ribose sugar ring or the base. Various connection methods can be referred to in the literature: Muthiah Manoharan et.al.siRNA conjugates carrying sequentially assembled trivalent N-acetylgalactosamine linked through nucleosides elicit robust gene silencing in vivo inhepatocytes.ACS Chemical biology, 2015, 10(5): 1181-7.

[0295] In some embodiments, the siRNA and the conjugated group can be connected by acid-labile or reducible chemical bonds, which can be degraded in the acidic environment of the cell endosome, thereby making the siRNA free. For non-degradable conjugation methods, the conjugated group can be connected to the sense strand of the siRNA, thereby minimizing the effect of conjugation on the activity of the siRNA.

[0296] In some embodiments, the pharmaceutically acceptable targeting group may be a ligand conventionally used in the field of siRNA administration, such as various ligands described in WO2009082607A2, which is fully incorporated into this specification by reference.

[0297] In some embodiments, the pharmaceutically acceptable targeting group can be selected from one or more of the ligands formed by the following targeting molecules or their derivatives: lipophilic molecules, such as cholesterol, bile acid, vitamins (such as vitamin E), lipid molecules of different chain lengths; polymers, such as polyethylene glycol; polypeptides, such as membrane-permeable peptides; aptamers; antibodies; quantum dots; carbohydrates, such as lactose, polylactose, mannose, galactose, N-acetylgalactosamine (GalNAc); folic acid (folate); receptor ligands expressed by hepatic parenchymal cells, such as asialoglycoproteins, asialosugar residues, lipoproteins (such as high-density lipoproteins, low-density lipoproteins, etc.), glucagon, neurotransmitters (such as adrenaline), growth factors, transferrin, etc.

[0298] In some embodiments, each ligand is independently selected from a ligand that can bind to a cell surface receptor. In some embodiments, at least one ligand is a ligand that can bind to a hepatocyte surface receptor. In some embodiments, at least one ligand is a ligand that can bind to a mammalian cell surface receptor. In some embodiments, at least one ligand is a ligand that can bind to a human hepatocyte surface receptor. In some embodiments, at least one ligand is a ligand that can bind to a liver surface asialoglycoprotein receptor (ASGPR). The types of these ligands are well known to those skilled in the art, and their function is generally to bind to a specific receptor on the surface of the target cell, mediating the delivery of the siRNA connected to the ligand to the target cell.

[0299] In some embodiments, the pharmaceutically acceptable targeting group can be any ligand that binds to an asialoglycoprotein receptor (ASGPR) on the surface of a mammalian hepatocyte. In some embodiments, each ligand is independently an asialoglycoprotein, such as asialo serum mucin (ASOR) or asialo fetuin (ASF). In some embodiments, the ligand is a sugar or a derivative of a sugar.

[0300] In some embodiments, at least one ligand is a sugar. In some embodiments, each ligand is a sugar. In some embodiments, at least one ligand is a monosaccharide, a polysaccharide, a modified monosaccharide, a modified polysaccharide or a sugar derivative. In some embodiments, at least one of the ligands may be a monosaccharide, a disaccharide or a trisaccharide. In some embodiments, at least one ligand is a modified sugar. In some embodiments, each ligand is independently selected from a polysaccharide, a modified polysaccharide, a monosaccharide, a modified monosaccharide, a polysaccharide derivative or a monosaccharide derivative. In some embodiments, each or at least one ligand is selected from the group consisting of the following sugars: glucose and its derivatives, mannan and its derivatives, galactose and its derivatives, xylose and its derivatives, ribose and its derivatives, fucose and its derivatives, lactose and its derivatives, maltose and its derivatives, arabinose and its derivatives, fructose and its derivatives and sialic acid.

[0301] In some embodiments, each of the ligands can be independently selected from D-mannopyranose, L-mannopyranose, D-arabinose, D-xylofuranose, L-xylofuranose, D-glucose, L-glucose, D-galactose, L-galactose, α-D-mannofuranose, β-D-mannofuranose, α-D-mannopyranose, β-D-mannopyranose, α-D-glucose, β-D-glucose, Sugar, α-D-glucofuranose, β-D-glucofuranose, α-D-fructofuranose, α-D-fructopyranose, α-D-galactopyranose, β-D-galactopyranose, α-D-galactofuranose, β-D-galactofuranose, glucosamine, sialic acid, galactosamine, N-acetylgalactosamine, N-trifluoroacetylgalactosamine, N-propionylgalactosamine, N-butyrylgalactosamine, N-isobutyrylgalactosamine , 2-amino-3-O-[(R)-1-carboxyethyl]-2-deoxy-β-D-glucopyranose, 2-deoxy-2-methylamino-L-glucopyranose, 4,6-dideoxy-4-formamido-2,3-di-O-methyl-D-mannopyranose, 2-deoxy-2-sulfoamino-D-glucopyranose, N-glycolyl-α-neuraminic acid, 5-thio-β-D-glucopyranose, 2, 3,4-tri-O-acetyl-1-thio-6-O-trityl-α-D-pyranoglucoside methyl ester, 4-thio-β-D-pyranose galactose, 3,4,6,7-tetra-O-acetyl-2-deoxy-1,5-dithio-α-D-pyranoglucoside ethyl ester, 2,5-anhydro-D-allose nitrile, ribose, D-ribose, D-4-thioribose, L-ribose or L-4-thioribose. Other selections of the ligand can refer to, for example, the records of CN105378082A, which are incorporated into this specification in full by reference.

[0302] In some embodiments, the pharmaceutically acceptable targeting group in the siRNA conjugate can be galactose or N-acetylgalactosamine, wherein the galactose or N-acetylgalactosamine molecule can be monovalent, divalent, trivalent, or tetravalent. It should be understood that the monovalent, divalent, trivalent, and tetravalent herein refer to the molar ratio of the siRNA molecule to the galactose or N-acetylgalactosamine molecule in the siRNA conjugate after the siRNA molecule and the conjugated group containing the galactose or N-acetylgalactosamine molecule as the targeting group form the siRNA conjugate respectively: 1, 1: 2, 1: 3, or 1: 4. In some embodiments, the pharmaceutically acceptable targeting group is N-acetylgalactosamine. In some embodiments, when the siRNA described in the present application is conjugated to a conjugated group containing N-acetylgalactosamine, the N-acetylgalactosamine molecule is trivalent or tetravalent. In some embodiments, when the siRNA described herein is conjugated to a conjugation group containing N-acetylgalactosamine, the N-acetylgalactosamine molecule is trivalent.

[0303] The targeting group can be connected to the siRNA molecule via a suitable linker, and those skilled in the art can select a suitable linker according to the specific type of the targeting group. For these linkers, the types of targeting groups and the connection mode with siRNA, please refer to the disclosure of WO2015006740A2, which is incorporated into this specification in its entirety by reference.

[0304] siRNA Synthesis Method

[0305] By the conventional solid phase phosphoramidite method in the art, nucleoside monomers are connected one by one from the 3'-5' direction according to the nucleotide arrangement order. Each connection of a nucleoside monomer includes four steps of deprotection, coupling, oxidation or sulfurization, and capping. Among them, when phosphate is used to connect two nucleotides, when the latter nucleoside monomer is connected, four steps of deprotection, coupling, oxidation, and capping are included. When thiophosphate is used to connect two nucleotides, when the latter nucleoside monomer is connected, four steps of deprotection, coupling, sulfurization, and capping are included. The present invention selects nucleotide monomers according to the synthetic target sequence, and the selected nucleotide monomers are nucleotide monomers commonly used by those skilled in the art. For example, the nucleotide monomers for synthesizing A can be, but are not limited to, adenosine-3-phosphate. It should be understood that these monomers, when present in oligonucleotides, are interconnected by 5'-3' phosphodiester bonds or 5'-3' thiophosphate groups. When, for example, the 3' position of the last nucleotide in the 5' to 3' direction is a hydroxyl group, it is achieved according to conventional means of the art.

[0306] For example, the synthesis conditions of the siRNA of the present application can be as follows:

[0307] The nucleoside monomer is provided in a 0.1M acetonitrile solution. The conditions of the deprotection reaction in each step are the same, that is, the reaction temperature is 25°C, the reaction time is 70 seconds, the deprotection reagent is a dichloroacetic acid dichloromethane solution (3% V / V), and the molar ratio of dichloroacetic acid to the 4,4'-dimethoxytrityl protecting group on the solid phase carrier is 5:1.

[0308] The coupling reaction conditions include: a reaction temperature of 25° C., a reaction time of 600 seconds, a coupling reagent selected from a 0.25 M acetonitrile solution of 5-ethylthio-1H-tetrazole (ETT), a molar ratio of the nucleic acid sequence connected to the solid phase support to the nucleoside monomer of 1:10, and a molar ratio of the nucleic acid sequence connected to the solid phase support to the coupling reagent of 1:65.

[0309] The oxidation reaction conditions include: a reaction temperature of 25° C., a reaction time of 15 seconds, an oxidizing agent selected from a 0.05M iodine tetrahydrofuran solution, and a molar ratio of the oxidizing agent to the nucleic acid sequence connected to the solid phase support in the coupling step of 30:1. The reaction is carried out in a mixed solvent of tetrahydrofuran: water: pyridine = 3:1:1.

[0310] The sulfurization reaction conditions include: a reaction temperature of 25° C., a reaction time of 300 seconds, a sulfurization reagent selected from hydrogenated xanthan, and a molar ratio of the sulfurization reagent to the nucleic acid sequence connected to the solid phase support in the coupling step of 120: 1. The reaction is carried out in a mixed solvent of acetonitrile: pyridine = 1: 1.

[0311] The capping reaction conditions include: a reaction temperature of 25° C., a reaction time of 15 seconds, a capping reagent selected from a mixed solution of CapA (10% acetic anhydride acetonitrile solution) and CapB (10% N-methylimidazole pyridine / acetonitrile solution) in a molar ratio of 1:1, and a molar ratio of the capping reagent to the nucleic acid sequence connected to the solid phase carrier is 1:1:1 of acetic anhydride:N-methylimidazole:nucleic acid sequence connected to the solid phase carrier.

[0312] After all the nucleoside monomers are connected, the nucleic acid sequence connected to the solid phase carrier is cut, deprotected, purified, and desalted in sequence to obtain the siRNA sense chain and antisense chain, and finally the two chains are heated and annealed to obtain the product.

[0313] Methods for cleavage, deprotection, purification, desalting and annealing are well known in the art. For example, cleavage and deprotection are performed by contacting the nucleotide sequence connected to the solid phase carrier with concentrated ammonia; purification is performed by chromatography; desalting is performed by reverse phase chromatography; and mixing the sense strand and the antisense strand in equal molar ratios under different stringent conditions and then gradually cooling.

[0314] The synthesized siRNAs are shown in Table 1.

[0315] siRNA conjugate synthesis method

[0316] Take the synthesis of L96 as an example:

[0317]

[0318] In the first step, DMTr-L96 and succinic anhydride are reacted to obtain compound L96-A:

[0319] Preparation process: DMTr-L96, succinic anhydride, 4-dimethylaminopyridine and diisopropylethylamine were added to dichloromethane, stirred at 25°C for 24 hours, and then the reaction solution was washed with 0.5M triethylamine phosphate, the aqueous phase was washed three times with dichloromethane, and the organic phases were combined and evaporated to dryness under reduced pressure to obtain a crude product. Then, column chromatography was used for purification to obtain pure L96-A.

[0320] In the second step, L96-A is reacted with NH2-SPS to obtain L96-B:

[0321]

[0322] Preparation process: L96-A, O-benzotriazole-tetramethyluronium hexafluorophosphate (HBTU) and diisopropylethylamine (DIPEA) are mixed and dissolved in acetonitrile, stirred at room temperature for 5 minutes to obtain a uniform solution, aminomethyl resin (NH2-SPS, 100-200 mesh) is added to the reaction liquid, and the shaking reaction is started at 25°C. After 18 hours of reaction, the filter cake is filtered and washed with dichloromethane and acetonitrile in turn to obtain a filter cake. The obtained filter cake is capped with a CapA / CapB mixed solution to obtain L96-B, which is a solid phase carrier containing a conjugate molecule, and then the nucleoside monomer is connected to the conjugate molecule under a coupling reaction, and then the siRNA sense chain connected to the conjugate molecule is synthesized according to the siRNA molecule synthesis method described above, and the siRNA antisense chain is synthesized using the siRNA molecule synthesis method described above, and annealing is performed to generate the siRNA conjugate of this application.

[0323] The synthesized siRNA conjugates are shown in Table 2.

[0324] Pharmaceutical composition

[0325] The present application provides a pharmaceutical composition, which contains the siRNA described above as an active ingredient and a pharmaceutically acceptable carrier.

[0326] The pharmaceutically acceptable carrier may be a carrier conventionally used in the field of siRNA administration, such as, but not limited to, lipid nanoparticles (LNP), magnetic nanoparticles (e.g., nanoparticles based on Fe3O4 or Fe2O3), carbon nanotubes, mesoporous silicon, calcium phosphate nanoparticles, polyethylenimine (PEI), polyamidoamine (PAMAM),

[0327] dendrimer), poly(L-lysine), chitosan, 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), poly(D&L-lactic / glycolic acid) copolymer (PLGA), poly(2-aminoethyl ethylene phosphate), poly(2-dimethylaminoethyl methacrylate), and one or more of PDMAEMA and their derivatives.

[0328] There is no special requirement for the content of siRNA and pharmaceutically acceptable carrier in the pharmaceutical composition, and the content of each component can be the conventional content.

[0329] In some embodiments, the pharmaceutical composition may further include other pharmaceutically acceptable excipients, which may be one or more of various preparations or compounds conventionally used in the art. For example, the other pharmaceutically acceptable excipients may include at least one of a pH buffer, a protective agent, and an osmotic pressure regulator.

[0330] The pH buffer may be a tris(hydroxymethyl)aminomethane hydrochloride buffer with a pH value of 7.5-8.5 and / or a phosphate buffer with a pH value of 5.5-8.5, for example, a phosphate buffer with a pH value of 5.5-8.5.

[0331] The protective agent may be at least one of inositol, sorbitol, sucrose, trehalose, mannose, maltose, lactose and glucose. Based on the total weight of the pharmaceutical composition, the content of the protective agent may be 0.01-30% by weight.

[0332] The osmotic pressure regulator can be sodium chloride and / or potassium chloride. The content of the osmotic pressure regulator makes the osmotic pressure of the pharmaceutical composition 200-700 milliosmole / kilogram (mOsm / kg). According to the desired osmotic pressure, those skilled in the art can easily determine the content of the osmotic pressure regulator.

[0333] In some embodiments, the pharmaceutical composition can be a liquid preparation, such as an injection; or a lyophilized powder injection, which is mixed with a liquid excipient during administration to prepare a liquid preparation. The liquid preparation can be, but is not limited to, administered subcutaneously, intramuscularly or intravenously, and can also be, but is not limited to, administered to the lungs by spraying, or administered to other organs (such as the liver) through the lungs by spraying. In some embodiments, the pharmaceutical composition is used for intravenous administration.

[0334] In some embodiments, the pharmaceutical composition can be in the form of a liposome formulation. In some embodiments, the pharmaceutically acceptable carrier used in the liposome formulation comprises an amine-containing transfection compound (hereinafter also referred to as an organic amine), a helper lipid and / or a pegylated lipid.

[0335] The following examples are used to further illustrate the present invention, but do not impose any limitation on the present invention.

[0336] Example

[0337] Other objects, features and advantages of the present disclosure will become apparent from the following detailed description. However, it should be understood that the detailed description and specific examples (although representing specific embodiments of the present disclosure) are given for illustrative purposes only, because after reading the detailed description, various changes and modifications made within the spirit and scope of the present disclosure will become apparent to those skilled in the art.

[0338] The experimental techniques and experimental methods used in this example are all conventional technical methods unless otherwise specified. For example, the experimental methods in the following examples that do not specify specific conditions are usually carried out under conventional conditions such as those described in Sambrook et al., Molecular Cloning: A Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1989), or under conditions recommended by the manufacturer. The materials, reagents, etc. used in the examples can be obtained through regular commercial channels unless otherwise specified.

[0339] Example 1 Preparation of siRNA

[0340] The siRNA molecules with the following sequences were synthesized by Tianlin Biotechnology (Shanghai) Co., Ltd.

[0341] Table 1 siRNA and its sequence

[0342]

[0343]

[0344]

[0345]

[0346]

[0347]

[0348]

[0349]

[0350]

[0351]

[0352]

[0353]

[0354] Among them, each of the capital letters "G", "C", "A", "T" and "U" generally represents a nucleotide containing guanine, cytosine, adenine, thymine and uracil as a base, respectively; lowercase letters a, u, c, g: represent 2'-methoxy modified nucleotides; Af, Gf, Cf, Uf: represent 2'-fluoro modified nucleotides; d: represents that the nucleotide adjacent to the right of the letter d is a 2'-deoxyribonucleotide; lowercase letter s represents that the two nucleotides adjacent to the left and right of the letter s are connected by a thiophosphate group; P1: represents that the nucleotide adjacent to the right of P1 is a 5'-phosphate nucleotide; EVP: represents that the nucleotide adjacent to the right of EVP is a 5'-trans vinylphosphonate nucleotide; (Underline + Bold + Italic): indicates GNA-modified nucleotides.

[0355] The siRNA conjugate with the following sequence was synthesized by Tianlin Biotechnology (Shanghai) Co., Ltd.:

[0356] Table 2 siRNA conjugates and their sequences:

[0357]

[0358]

[0359]

[0360]

[0361]

[0362] Wherein, L96 is connected to the 3' end of the sense strand in Table 1 or the blunt end formed by the 3' end of the sense strand through a phosphodiester bond, and L96 is:

[0363]

[0364] In Table 1 and Table 2, if there is no P1 or EVP on the left side of the 5' terminal nucleotide of the sense strand, the modified sense strand, and the modified sense strand connected to the conjugated group, it means that the 5' terminal nucleotide is not connected to a 5' phosphate group or a 5' phosphate derivative group (i.e., the ribose group of the 5' terminal nucleotide is a 5' hydroxyl group), and its structure is shown in Formula X:

[0365]

[0366] Wherein, Base represents a base, such as A, U, G, C or T; R is hydroxyl or hydrogen or is substituted by various groups known to those skilled in the art, for example, R can be 2'-fluoro (2'-F), 2'-alkoxy, 2'-substituted alkoxy, 2'-alkyl, 2'-substituted alkyl, 2'-amino, 2'-substituted amino.

[0367] In Table 1 and Table 2, if there is no P1 or EVP on the left side of the 5' terminal nucleotide of the antisense strand and the modified antisense strand, it means that the 5' terminal nucleotide is not connected to a 5' phosphate group or a 5' phosphate derivative group, and its structure is also shown in Formula X.

[0368] In Table 1 and Table 2, the 3' position of the 3' terminal nucleotide of the sense strand and the modified sense strand, and the 3' terminal nucleotide of the antisense strand and the modified antisense strand is a hydroxyl group.

[0369] Example 2 siRNA inhibits SMAD3 gene expression

[0370] Experimental Materials:

[0371] HepG2 cells were purchased from the Cell Bank of Type Culture Collection Committee of the Chinese Academy of Sciences, catalog number SCSP-510;

[0372] RNA extraction kit, catalog number QIAGEN-74106;

[0373] RNAiMAX transfection reagent, purchased from Invitrogen, catalog number 13778-150;

[0374] MEM medium, purchased from Gibco, catalog number 41090036;

[0375] Reverse transcription kit ( III 1st Strand cDNA Synthesis Kit (+gDNA wiper), purchased from Vazyme, catalog number R312-02;

[0376] TaqMan TM Gene expression master mix, purchased from Applied Biosystems, catalog number 4369016;

[0377] Opti-MEM: purchased from Gibco, catalog number 31985070;

[0378] Primer and probe set targeting SMAD3 were purchased from Thermo, Hs00969210_m1;

[0379] TaqMan Gene Expression Assay (GAPDH), purchased from Thermo, ID-Hs99999905_m1.

[0380] Experimental methods:

[0381] 1. HepG2 cells were plated in fresh MEM medium in a 96-well plate and cultured for 48 hours. The cultured cells were resuspended in MEM medium without PS (penicillin-streptomycin mixture) to a density of 1.11×10 5 / mL of cell suspension was plated into a 96-well plate, and 90 μL of cell suspension was added to each well, i.e., 10,000 cells / well.

[0382] 2. The dry powder of the siRNA to be tested was centrifuged at low temperature and high speed, and then dissolved with ultrapure distilled water (ULtraPureDistilled Water) to prepare a 100 μM siRNA stock solution.

[0383] 3. Prepare 0.1nM siRNA transfection dilution solution

[0384] (1) Preparation of 0.1 μM siRNA stock solution:

[0385] a. Take 2 μL of the 100 μM siRNA stock solution prepared in step 2 above, add 18 μL of ultrapure distilled water to obtain a siRNA dilution solution with a final concentration of 10 μM;

[0386] b. Take 2 μL of the 10 μM siRNA dilution prepared in step a, add 18 μL of ultrapure distilled water to obtain a 1 μM siRNA dilution;

[0387] c. Take 2 μL of the 1 μM siRNA dilution prepared in step b, add 18 μL of ultrapure distilled water to obtain a 0.1 μM siRNA stock solution;

[0388] (2) Take 2 μL of the 0.1 μM siRNA stock solution prepared in step c above and add 98 μL of Opti-MEM to obtain a 2 nM siRNA dilution solution;

[0389] (3) 3 μL RNAiMAX transfection reagent was added to 97 μL Opti-MEM to obtain RNAiMAX transfection reagent diluent; RNAiMAX transfection reagent diluent was mixed with the above 2nM siRNA diluent at a volume ratio of 1:1, allowed to stand for 5 minutes, and 10 μL of the transfection mixture was added to a 96-well plate to transfect the cultured HepG2 cells (final volume 100 μL, siRNA concentration in this system was 0.1 nM).

[0390] 10 nM siRNA transfection diluent can be prepared by similar operation as above.

[0391] 4. Culture for 48 hours after transfection and set up 2 replicates for each concentration.

[0392] 5. Extract total RNA according to the instructions of the RNA extraction kit.

[0393] 6. Use a reverse transcription kit to reverse transcribe total RNA into cDNA. Follow the steps below:

[0394] a) Remove gDNA using gDNA enzyme according to the table below;

[0395] Volume / μL 5×gDNABuffer 2 Total RNA samples 8

[0396] 42°C, 2 min;

[0397] b) adding the following reagents to the system obtained in step a) and performing reverse transcription:

[0398] Volume / μL The mixed solution obtained in step a) 10 10×RT Mix 2 HiScript III Enzyme Mix 2 <![CDATA[Oligo(dT) 20 VN]]> 1 Random hexamers 1 <![CDATA[RNase-free ddH2O]]> 4

[0399] 50℃, 15min; 85℃, 5s.

[0400] c) The reverse transcription products were stored at 4°C for real-time PCR analysis.

[0401] 7. Perform Real-time PCR Analysis

[0402] a) Prepare qPCR reaction mixture as shown in the table below. Keep all reagents on ice during the entire operation.

[0403]

[0404] b) Perform qPCR procedure as follows

[0405] 50°C, 2 minutes, 95°C, 10 minutes;

[0406] 95°C, 15 seconds, 60°C, 1 minute (40 cycles of this operation).

[0407] 8. Results Analysis

[0408] a) Quant Studio 6Flex software was used with default settings to automatically calculate the Ct value;

[0409] b) Calculate the relative expression of genes using the following formula:

[0410] ΔCt=Ct(SMAD3 gene)-Ct(GAPDH)

[0411] ΔΔCt=ΔCt(test sample group)-ΔCt(Mock group)

[0412] mRNA expression relative to the Mock group = 2 -ΔΔCt .

[0413] Mock: Compared with the test sample group, the group without siRNA added.

[0414] Inhibition rate (%) = (relative expression of mRNA in the Mock group - relative expression of mRNA in the test sample group) / relative expression of mRNA in the Mock group × 100%

[0415] 9. Experimental Results

[0416] siRNA concentrations of 10 nM and 0.1 nM were selected for testing.

[0417] Table 3 Inhibition rate of siRNA of the present invention

[0418]

[0419]

[0420]

[0421] Table 4 Inhibition rate of control siRNA

[0422] siRNA ID 10 nM-48h 0.1nM-48h N-ER-FY027052 -0.11％ 9.24％

[0423] It can be seen from Tables 3 and 4 that the siRNA of the present invention can significantly inhibit the expression of the SMAD3 gene at both 10 nM and 0.1 nM, wherein the 48 h inhibition rate at 10 nM is as high as more than 65%, even as high as more than 75%, preferably as high as more than 85%, and the 48 h inhibition rate at 0.1 nM is as high as more than 50%, even as high as more than 70%, preferably as high as more than 80%.

[0424] Example 3 IC of siRNA inhibiting SMAD3 gene expression 50 Determination

[0425] According to the method similar to Example 2, IC of siRNA inhibiting SMAD3 gene expression was performed. 50 The concentrations of siRNA used for transfection were 10 nM, 2.5 nM, 0.625 nM, 0.15625 nM, 0.039 nM, 0.0098 nM, 0.00244 nM, and 0.0006 nM, respectively. IC was determined using GraphPad Prism software. 50 calculate.

[0426] Result analysis:

[0427] a) Quant Studio 7 software was used with default settings to automatically calculate the Ct value;

[0428] b) Calculate the relative expression of genes using the following formula:

[0429] ΔCt=Ct(SMAD3 gene)–Ct(GAPDH)

[0430] ΔΔCt=ΔCt(test sample group)-ΔCt(Mock group), where the Mock group represents the group without siRNA added compared with the test sample group;

[0431] mRNA expression relative to the Mock group = 2 -ΔΔCt

[0432] Inhibition rate (%) = (relative expression of mRNA in the Mock group - relative expression of mRNA in the test sample group) / relative expression of mRNA in the Mock group × 100%

[0433] The log value of siRNA concentration was used as the X-axis and the percentage inhibition rate was used as the Y-axis. The “log (inhibitor) vs. response-variable slope” function module of the analysis software GraphPadPrism 8 was used to fit the dose-effect curve to obtain the IC of each siRNA. 50 value.

[0434] The fitting formula is: Y = Bottom + (Top-Bottom) / (1 + 10^((logIC 50 -X)*HillSlope))

[0435] Among them: Top represents the percentage inhibition rate at the top platform, and the Top standard of the curve is generally between 80% and 120%; Bottom represents the percentage inhibition rate at the bottom platform, and the Bottom of the curve is generally between -20% and 20%; HillSlope represents the slope of the percentage inhibition rate curve.

[0436] The experimental results are shown in Table 5.

[0437] Table 5 IC of siRNA 50

[0438] siRNA ID <![CDATA[IC 50 (nM)]]> N-ER-FY027001M3 0.426 N-ER-FY027004M3 0.183 N-ER-FY027013M3 0.170 N-ER-FY027020M3 0.257 N-ER-FY027030M3 0.489 N-ER-FY027031M3 0.194 N-ER-FY027033M3 0.051

[0439] As can be seen from Table 5, the siRNA of the present invention can significantly inhibit the expression of SMAD3 gene, IC 50 About 0.051-0.489nM, lowest to 0.051nM.

[0440] Example 4 Determination of the inhibition rate of siRNA conjugates in inhibiting SMAD3 gene expression

[0441] 4.1 Test materials:

[0442] Human primary hepatocytes PHH cells were provided by Shanghai WuXi AppTec Pharmaceuticals Co., Ltd.;

[0443] PHH medium: invitroGRO CP Medium serum free BIOVIT, catalog number: S03316;

[0444] RNAiMAX transfection reagent, purchased from Invitrogen, catalog number: 13778-150;

[0445] 96Kit, purchased from QIAGEN, catalog number: QIAGEN-74182;

[0446] Reverse transcription kit ( III 1st Strand cDNA Synthesis Kit (+gDNA wiper), purchased from Vazyme, catalog number R312-02;

[0447] FastStart Universal Probe master, purchased from Roche, catalog number: 4913918001;

[0448] Primers targeting SMAD3 and GAPDH were provided by Shanghai WuXi AppTec Co., Ltd.

[0449] 4.2 Test methods

[0450] siRNA conjugates (final concentrations of siRNA conjugates were 10 nM and 0.5 nM, respectively, in duplicate) were transfected into PHH cells by the following process: frozen PHH cells were taken, revived, counted, and the number of cells was adjusted to 6 × 10 5 cells / mL, applied simultaneously RNAiMax transfection reagent was used to transfer siRNA conjugates into cells, and 54,000 cells were seeded into 96-well plates at a density of 1:1. 100 μL of PHH medium was added to each well. The cells were cultured in a 5% CO2, 37°C incubator. After 48 hours, the medium was removed and the cells were collected for total RNA extraction. Use according to the kit product instructions. Total RNA was extracted using 96Kit.

[0451] siRNA conjugates (final concentrations of siRNA conjugates were 200 nM and 10 nM, respectively, in duplicate) were freely taken up by PHH cells, and the process was as follows: frozen PHH cells were taken, revived, counted, and the number of cells was adjusted to 6 × 10 5 Cells / mL, siRNA conjugates were added at the same time, and the cells were seeded into 96-well plates at a density of 54,000 cells per well, with 100 μL of culture medium per well. The cells were cultured in a 5% CO2, 37°C incubator. After 48 hours, the culture medium was removed and the cells were collected for total RNA extraction. Use according to the kit product instructions Total RNA was extracted using 96Kit.

[0452] The extracted total RNA was reverse transcribed into cDNA by reverse transcription reaction similar to that in Example 2, and the reverse transcribed SMAD3 cDNA was quantitatively amplified by qPCR. GAPDH cDNA was amplified in parallel as an internal control. The PCR reaction program was: 95°C, 10 minutes, then entered the cycle mode, 95°C, 15 seconds, then 60°C, 60 seconds, for a total of 40 cycles.

[0453] Result analysis:

[0454] a) Quant Studio 7 software was used with default settings to automatically calculate the Ct value;

[0455] b) Calculate the relative expression of genes using the following formula:

[0456] ΔCt=Ct(SMAD3 gene)–Ct(GAPDH)

[0457] ΔΔCt=ΔCt(test sample group)−ΔCt(Mock group), where the Mock group represents a group without the addition of siRNA conjugates compared with the test sample group;

[0458] mRNA expression relative to the Mock group = 2 -ΔΔCt

[0459] Inhibition rate (%) = (relative expression of mRNA in the Mock group - relative expression of mRNA in the test sample group) / relative expression of mRNA in the Mock group × 100%

[0460] The experimental results are shown in Table 6.

[0461] Table 6 Inhibition rate of SMAD3 gene expression by siRNA conjugates

[0462]

[0463]

[0464]

[0465] Note: “--” results are not shown.

[0466] As can be seen from Table 6, the siRNA conjugates of the present invention can significantly inhibit SMAD3 gene expression. Under free uptake conditions, the inhibition rate at a concentration of 200 nM is as high as about 75% or more, and the inhibition rate at a concentration of 10 nM is as high as about 65% or more, and even as high as about 70% or more.

[0467] Example 5 Silencing effect of siRNA conjugates in mice expressing the human SMAD3 (hSMAD3) gene

[0468] Experimental Materials:

[0469] Equipment Name / Reagent Name brand Model / Article No. Multifunctional ELISA reader PE Ensight <![CDATA[Phospha-Light TM SEAP Reporter Gene Assay System]]> Invitrogen T1015 Detection plate (384 wells) PE 6057480 PBS solution MeilunBio MA00-15-D <![CDATA[Phospha-Light TM Genetic Testing Kit]]> Themo Fisher Scientific T2087

[0470] (1) Construction of hSMAD3 gene overexpressing mouse model using AAV

[0471] C57BL / 6 mice aged 6-8 weeks (provided by Beijing Weitong Lihua Experimental Animal Technology Co., Ltd.) were brought into the facility. After adaptive feeding for 3-5 days, a single injection of adeno-associated virus AAV (pAAV[Exp]-CBh>{SMAD3 CDS(ns)}:T2A:SEAP, virus provided by Yunzhou Biotechnology (Guangzhou) Co., Ltd.) carrying the hSMAD3 gene in PBS solution was performed through the tail vein for target gene overexpression modeling. The administration volume was 100 μL (virus amount 4*1011 vg) / mouse, and then the mice were fed with normal feed.

[0472] (2) Investigation of the efficacy of siRNA silencing in hSMAD3 mouse model

[0473] 14 days after AAV virus injection, the mice were divided into groups (6 in each group) and subcutaneously administered a single 1, 3 or 10 mpk dose of N-ER-FY027054M2L96, N-ER-FY027054M6L96, N-ER-FY027055M3L96, N-ER-FY027055M7L96, N-ER-FY027167M6L96, N-ER-FY027167M8L96 and N-ER-FY027186M8L96. SEAP protein expression (i.e., hSMAD3 protein expression) was detected on days 7, 14, 21, 28, 35 and 42 after administration, see Table 7.

[0474] (3) Drug preparation

[0475] a. Centrifuge the drug powder for 10 seconds, open the lid in a draft-free biosafety cabinet, and add 1 mL of enzyme-free sterile PBS solution;

[0476] b. Vortex and centrifuge immediately, let stand for 5 minutes to fully dissolve, and draw 10 μL of liquid for concentration detection;

[0477] c. Use the calibrated Nanodrop instrument RNA mode to measure the concentration of the mother solution;

[0478] d. Calculate the volume of PBS solution to be added based on the concentration of the mother solution;

[0479] e. Transfer 900 μL of the mother solution in the original tube into a 5 mL centrifuge tube and add the PBS solution to be added;

[0480] f. After vortexing, centrifuge immediately and draw 10 μL of liquid for concentration detection. The concentration should be within ±10% of the theoretical concentration.

[0481] g. Transfer the prepared drugs to the animal room for administration, avoiding ultraviolet light exposure.

[0482] (4) Detection steps

[0483] a.1×Dilution buffer preparation:

[0484] Reagent name Volume ratio ddH2O 4 5×Dilution buffer 1

[0485] Vortex to mix and set aside.

[0486] b. Sample dilution

[0487] (diluted 1000 times)

[0488] Serum volume (μL) 1×Dilution buffer (μL) Enzyme-free water (μL) Dilution multiple 6 / 54 10 6 / 54 10 5 45 / 10

[0489] (diluted 300 times)

[0490] Serum volume (μL) 1×Dilution buffer (μL) Enzyme-free water (μL) Dilution multiple 6 / 114 20 4 56 / 15

[0491] Mix well and set aside;

[0492] c. Sample denaturation

[0493] Place the diluted sample in a PCR instrument and incubate at 65°C for 30 minutes (the PCR program has been set to store at 4°C after incubation), take it out and place it in an ice box to return to room temperature for later use;

[0494] d. Luminescence reaction pretreatment

[0495] The sample detection layout was carried out according to the plate layout in Table 8. 20 μL of the denatured sample cooled to 4°C was added to each well, followed by 20 μL of Assay buffer, and the cells were incubated at 25°C and 300 times / min for 5 minutes.

[0496] e. Dilution of CSPD substrate (prepare immediately before use and keep away from light).

[0497] Reagent name Volume ratio CSPD substrate 1 1×Reaction buffer 19

[0498] Vortex to mix and set aside.

[0499] f. Luminescent reaction

[0500] Add 20 μL of CSPD substrate dilution to each well and incubate at 25°C and 300 times / min for 5 minutes.

[0501] g.Ensight measurement

[0502] Chemiluminescence method: (Detection type: Luminescence; Distance between plate and detector: 0.1mm; Detection time: 0.1s)

[0504] h. Calculation of results

[0505] The gene expression inhibition rate was calculated based on the light intensity value detected by the instrument. The calculation formula was: inhibition rate % = Average (drug administration group) / Average (blank group) * 100%. The results are shown in Table 7.

[0506] Table 7:

[0507] siRNA ID D7 D14 D21 D28 D35 D42 N-ER-FY027054M2L96(1mpk) 19.89 26.27 18.47 4.98 12.49 36.72 N-ER-FY027054M2L96(3mpk) 57.16 63.94 63.17 57.99 55.43 -- N-ER-FY027054M6L96(1mpk) 24.57 25.64 26.38 31.57 17.54 -- N-ER-FY027054M6L96(3mpk) 62.22 68.37 72.30 67.29 63.49 49.83 N-ER-FY027055M3L96(1mpk) 28.08 40.06 41.33 35.43 19.80 -- N-ER-FY027055M3L96(3mpk) 69.61 80.59 78.00 70.46 64.91 50.75 N-ER-FY027055M7L96(1mpk) 37.16 39.83 45.81 36.05 39.67 -- N-ER-FY027055M7L96(3mpk) 67.08 73.00 69.99 69.08 59.71 42.52 N-ER-FY027167M6L96(3mpk) 34.24 70.96 71.73 76.58 66.18 56.82 N-ER-FY027167M6L96(10mpk) 69.02 80.60 87.68 81.96 85.52 70.45 N-ER-FY027167M8L96(3mpk) 49.08 71.95 76.08 75.21 72.16 67.07 N-ER-FY027186M8L96(3mpk) 56.35 73.16 82.41 84.57 81.65 75.10

[0508] As can be seen from Table 7, the siRNA conjugates of the present application have a high inhibitory activity on the hSMAD3 gene in vivo and can reduce the hSMAD3 expression level for a long time. At a dose of 3 mpk, the inhibition rate during the 14th day of the test determination was above about 60%, even above about 70%, and during the 42nd day of the test determination, the inhibition rate was above about 50%, even above about 65%, and better above about 75%.

[0509] Table 8: Board Layout

[0510]

[0511]

[0512] The above embodiments of the present disclosure are merely examples for clearly illustrating the present disclosure, and are not intended to limit the implementation methods of the present disclosure. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the claims of the present disclosure.

Claims

1. An siRNA for inhibiting the expression of SMAD family member 3 (SMAD3) gene, the siRNA comprising a sense strand and an antisense strand, wherein each nucleotide in the siRNA is independently a modified or unmodified nucleotide, wherein the sense strand comprises a nucleotide sequence I, and the antisense strand comprises a nucleotide sequence II, wherein the nucleotide sequence I and the nucleotide sequence II are at least partially reverse-complemented to form a double-stranded region, wherein the nucleotide sequence I and the nucleotide sequence II are selected from the following sequences: (1) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 347, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 348: 5'-AGCCUGGUCAAGAAACU-3'(SEQ ID NO:347) 5'-AGUUUCUUGACCAGGCU-3' (SEQ ID NO:348); (2) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 349, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 350: 5'-CGUCAACACCAAGUG-3'(SEQ ID NO:349) 5'-CACUUGGUGUUGACG-3' (SEQ ID NO:350); (3) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 73, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 74: 5'-ACACCAGUGCAUCACCAU-3'(SEQ ID NO:73) 5'-AUGGUGAUGCACUUGGUGU-3' (SEQ ID NO:74); (4) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 351, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 352: 5'-GUGACCACCAGAUGA-3'(SEQ ID NO:351) 5'-UCAUCUGGUGGUCAC-3' (SEQ ID NO: 352); (5) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 353, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 354: 5'-CGGAGACACAUCGGAA-3'(SEQ ID NO:353) 5'-UUCCGAUGUGUCUCCG-3' (SEQ ID NO:354); (6) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 355, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 356: 5'-CGUGCGGCUCUACUA-3'(SEQ ID NO:355) 5'-UAGUAGAGGCCGCACG-3' (SEQ ID NO: 356); (7) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 357, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 358: 5'-GUGACAGCGCUAU-3'(SEQ ID NO:357) 5'-AUAGCGCUGUCAC-3' (SEQ ID NO: 358); (8) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 359, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 360: 5'-CAACUGUAACCAGCGCUA-3'(SEQ ID NO:359) 5'-UAGCGCUGGUUACAGUUG-3' (SEQ ID NO:360); (9) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 361, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 362: 5'-ACCAGUUGACCCGAA-3'(SEQ ID NO:361) 5'-UUCGGGUCAACUGGU-3' (SEQ ID NO:362); (10) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 363, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 364: 5'-GGAGUACAGGAGACAGA-3'(SEQ ID NO:363) 5'-UCUGUCUCCUGUACUCC-3' (SEQ ID NO: 364); wherein the nucleotide sequence I is not SEQ ID NO: 247, and the nucleotide sequence II is not SEQ ID NO: 248; (11) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 365, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 366: 5'-CUGGAUUGAGCUGCA-3'(SEQ ID NO:365) 5'-UGCAGCUCAAUCCAG-3' (SEQ ID NO: 366); (12) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 273, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 274: 5'-GAUUGAGCUGCACCUGAAU-3'(SEQ ID NO:273) 5'-AUUCAGGUGCAGCUCAAUC-3' (SEQ ID NO: 274); (13) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 367, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 368: 5'-CUGAAUGGGCCUUU-3'(SEQ ID NO:367) 5'-AAAGGCCCAUUCAG-3' (SEQ ID NO:368); (14) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 369, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 370: 5'-CCAAGCAUCCGCUGUU-3'(SEQ ID NO:369) 5'-AACAGCGGAUGCUUGG-3' (SEQ ID NO:370); (15) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 371, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 372: 5'-CGCUGUUCCAGUGUGU-3'(SEQ ID NO:371) 5'-ACACACUGGAACAGCG-3' (SEQ ID NO: 372); (16) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 373, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 374: 5'-GUUCCAGUGUGUCUU-3'(SEQ ID NO:373) 5'-AAGACACACUGGAAC-3' (SEQ ID NO: 374); (17) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 375, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 376: 5'-GGAGAAAUGGGCGAG-3'(SEQ ID NO:375) 5'-CUCGCACCAUUUCUCC-3' (SEQ ID NO:376); (18) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 377, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 378: 5'-CAAGAGCCUGGUCA-3'(SEQ ID NO:377) 5'-UGACCAGGCUCUUG-3' (SEQ ID NO:378); (19) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 379, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 380: 5'-CUACCUGAGUGAAGAU-3'(SEQ ID NO:379) 5'-AUCUUCACUCAGGUAG-3' (SEQ ID NO:380); (20) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 381, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 382: 5'-GAGUGAAGAUGGAGAAA-3'(SEQ ID NO:381) 5'-UUUCUCCAUCUUCACUC-3' (SEQ ID NO: 382); (21) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 383, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 384: 5'-GAGGAGAAAUGGUGCGA-3'(SEQ ID NO:383) 5'-UCGCACCAUUUCUCCUC-3' (SEQ ID NO:384); (22) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 81, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 82; (23) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 83, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 84; (24) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 85, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 86; (25) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 118, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 119; (26) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 153, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 154; (27) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 155, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 156; (28) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 219, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 220; (29) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 340, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 341; (30) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 524, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 525: 5'-CCAGAUGAAC-3'(SEQ ID NO:524) 5'-GUUCAUCUGG-3' (SEQ ID NO:525); (31) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 526, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 527: 5'-CAGCAUGGACGCAGGU-3'(SEQ ID NO:526) 5'-ACCUGCGUCCAUGCCUG-3' (SEQ ID NO: 527); (32) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 528, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 529: 5'-CCAUCUCCUAC-3'(SEQ ID NO:528) 5'-GUAGGAGAUGG-3' (SEQ ID NO: 529); (33) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 530, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 531: 5'-ACCUGAAGA-3'(SEQ ID NO:530) 5'-UCUUCAGGU-3' (SEQ ID NO:531); (34) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 532, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 533: 5'-ACAAGGUCCUC-3'(SEQ ID NO:532) 5'-GAGGACCUUGU-3' (SEQ ID NO:533); (35) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 534, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 535: 5'-CAUCCGCUGUUCCAGUG-3'(SEQ ID NO:534) 5'-CACUGGAACAGCGGAUG-3' (SEQ ID NO: 535); (36) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 520, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 521; (37) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 393, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 394; (38) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 395, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 396; (39) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO: 397, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO: 398; (40) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:407, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:408; (41) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:427, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:428; (42) the nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:437, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:438; (43) The nucleotide sequence I comprises the nucleotide sequence shown in SEQ ID NO:441, and the nucleotide sequence II comprises the nucleotide sequence shown in SEQ ID NO:

442.

2. The siRNA according to claim 1, wherein the nucleotide sequence I and the nucleotide sequence II are substantially reverse complementary, essentially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there are no more than 3 base mismatches between the two nucleotide sequences; the substantially reverse complementary means that there are no more than 1 base mismatch between the two nucleotide sequences; and the completely reverse complementary means that there is no mismatch between the two nucleotide sequences.

3. The siRNA according to claim 1 or 2, wherein the sense strand further contains a nucleotide sequence III, and the antisense strand further contains a nucleotide sequence IV, and the lengths of the nucleotide sequence III and the nucleotide sequence IV are each independently 0-11 nucleotides, wherein the nucleotide sequence III is connected to the 5' end of the nucleotide sequence I, and the nucleotide sequence IV is connected to the 3' end of the nucleotide sequence II, and the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there is no more than one base mismatch between the two nucleotide sequences; and the completely reverse complementary means that there is no mismatch between the two nucleotide sequences; and / or, the nucleotide sequence III is connected to the 3' end of the nucleotide sequence I, and the nucleotide sequence IV is connected to the 5' end of the nucleotide sequence II, and the nucleotide sequence III and the nucleotide sequence IV are equal in length and are substantially reverse complementary or completely reverse complementary; the substantially reverse complementary means that there is no more than one base mismatch between the two nucleotide sequences; and the completely reverse complementary means that there is no mismatch between the two nucleotide sequences.

4. The siRNA according to any one of claims 1 to 3, wherein the siRNA comprises a sense strand and an antisense strand, wherein each nucleotide in the siRNA is independently a modified or unmodified nucleotide, wherein the sense strand contains nucleotide sequences I and III, and the antisense strand contains nucleotide sequences II and IV, and the nucleotide sequences I and III are at least partially reverse complementary to the nucleotide sequences II and IV to form a double-stranded region, wherein the nucleotide sequences I and III, the nucleotide sequences II and IV are selected from the following sequences: (1) The nucleotide sequences I and III comprise or consist of the nucleotide sequence shown in SEQ ID NO:465, and the nucleotide sequences II and IV comprise or consist of the nucleotide sequence shown in SEQ ID NO:

466.

5. The siRNA according to any one of claims 1 to 4, wherein the sense strand further comprises a nucleotide sequence V and / or the antisense strand further comprises a nucleotide sequence VI, the length of the nucleotide sequences V and VI is 0 to 3 nucleotides, the nucleotide sequence V is connected to the 3' end of the sense strand to form a 3' overhang of the sense strand and / or the nucleotide sequence VI is connected to the 3' end of the antisense strand to form a 3' overhang of the antisense strand; preferably, the length of the nucleotide sequence V or VI is 2 nucleotides; more preferably, the nucleotide sequence V or VI is two consecutive thymine deoxyribonucleotides or two consecutive uracil ribonucleotides; Alternatively, the nucleotide sequence V or VI is mismatched or complementary to the nucleotide at the corresponding position of the target mRNA.

6. The siRNA according to any one of claims 1-5, wherein the length of the double-stranded region is 15-30 nucleotide pairs; preferably, the length of the double-stranded region is 17-23 nucleotide pairs; more preferably, the length of the double-stranded region is 19-21 nucleotide pairs.

7. The siRNA according to any one of claims 1 to 6, wherein the sense strand or the antisense strand has 15-30 nucleotides; preferably, the sense strand or the antisense strand has 19-25 nucleotides; more preferably, the sense strand or the antisense strand has 19-23 nucleotides.

8. The siRNA according to any one of claims 1 to 7, wherein at least one nucleotide in the sense strand or the antisense strand is a modified nucleotide, and / or at least one phosphate group is a phosphate group having a modified group; preferably, the phosphate group having a modified group is a thiophosphate group formed by replacing one oxygen atom in the phosphodiester bond in the phosphate group with a sulfur atom; and / or, the siRNA comprises a sense strand that does not include a 3' overhanging nucleotide.

9. The siRNA according to any one of claims 1 to 8, wherein The 5' terminal nucleotide of the antisense strand is linked to a 5' phosphate group or a 5' phosphate-derivative group, or the 5' terminal nucleotide of the antisense strand is not linked to a 5' phosphate group or a 5' phosphate-derivative group.

10. The siRNA according to any one of claims 1 to 9, wherein the modified nucleotides are selected from 2'-fluoro-modified nucleotides, 2'-alkoxy-modified nucleotides, 2'-substituted alkoxy-modified nucleotides, 2'-alkyl-modified nucleotides, 2'-substituted alkyl-modified nucleotides, 2'-deoxynucleotides, 2'-amino-modified nucleotides, 2'-substituted amino-modified nucleotides, nucleotide analogs or a combination of any two or more thereof; Preferably, the modified nucleotide is selected from 2'-fluoro modified nucleotides, 2'-methoxy modified nucleotides, 2'-O-CH2-CH2-O-CH3 modified nucleotides, 2'-O-CH2-CH=CH2 modified nucleotides, 2'-CH2-CH2-CH=CH2 modified nucleotides, 2'-deoxynucleotides, nucleotide analogs or a combination of any two or more thereof.

11. The siRNA according to any one of claims 1 to 10, wherein each nucleotide in the sense strand and the antisense strand is independently a 2'-fluoro-modified nucleotide or a non-fluoro-modified nucleotide; Preferably, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 8, 9, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 5, 7, 8 and 9 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 8, 9 and 10 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 3, 5, 8, 10, 14, 16 and 18 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 3, 4, 5, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 8, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 3, 4, 5, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 4, 6, 12, 14, 16, 18 and 20 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluorinated modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; in the 5' to 3' direction, the 2'-fluorinated modified nucleotides are located at positions 2 and 14 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7 and 9 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 4, 5, 6, 8, 10, 12, 14, 16, 18 and 20 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 7 and 9 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14, and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 7, 9 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 7, 11, 13 and 15 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 8, 9, 10 and 12 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 7, 9, 11, 13 and 15 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 9, 11 and 13 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 7, 9, 11 and 13 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 3, 7, 8 and 9 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 3, 9, 11 and 13 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 3, 7, 9 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 7, 11 and 13 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 11, 12 and 13 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 3, 7, 11 and 16 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 3, 7, 11 and 17 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 3, 7, 11, 16 and 17 of the sense strand, and the remaining positions are non-fluorinated modified nucleotides; from 5' to 3', the 2'-fluorinated modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are non-fluorinated modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 5, 7 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 3, 7, 8 and 9 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 3, 7, 9 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Further preferably, each non-fluorinated modified nucleotide is a 2'-methoxy modified nucleotide, wherein the 2'-methoxy modified nucleotide refers to a nucleotide in which the 2'-hydroxyl group of the ribose group is replaced by a methoxy group.

12. The siRNA according to claim 11, wherein each non-fluorinated modified nucleotide is independently selected from a nucleotide or nucleotide analogue formed by replacing the hydroxyl group at the 2' position of the ribose group of the nucleotide with a non-fluorinated group, and the nucleotide analogue is selected from one of pseudouracil, isonucleotide, LNA, ENA, cET BNA, UNA and GNA.

13. The siRNA according to any one of claims 1 to 12, wherein each nucleotide in the sense strand and the antisense strand is independently a 2'-fluoro-modified nucleotide, a 2'-methoxy-modified nucleotide, a GNA-modified nucleotide, a 2'-deoxyribonucleotide, or a combination of any two or more thereof; Preferably, from 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 8, 9, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 14 and 16 of the antisense strand, the GNA modified nucleotide is located at position 6 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, the GNA modified nucleotide is located at position 7 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6 and 14 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 5, 7, 8 and 9 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 8, 9 and 10 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 3, 5, 8, 10, 14, 16 and 18 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 3, 4, 5, 7, 10 and 14 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 8, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 3, 4, 5, 7, 10 and 14 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 4, 6, 12, 14, 16, 18 and 20 of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2 and 14 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7 and 9 of the sense strand, the 2'-deoxyribonucleotide is located at position 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 4, 5, 6, 8, 10, 12, 14, 16, 18 and 20 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7 and 9 of the sense strand, the 2'-deoxyribonucleotide is located at position 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 9 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 11, 13 and 15 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 8, 9, 10 and 12 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 11, 13 and 15 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 9, 11 and 13 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 11 and 13 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 3, 7, 8 and 9 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 3, 9, 11 and 13 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 3, 7, 9 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 11 and 13 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 7, 11, 12 and 13 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 3, 7, 11 and 16 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 3, 7, 11 and 17 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 3, 7, 11, 16 and 17 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 6, 14 and 16 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides; from 5' to 3', the 2'-fluoro modified nucleotides are located at positions 2, 3, 4, 5, 7, 10 and 14 of the antisense strand, the GNA modified nucleotide is located at position 6 of the antisense strand, and the remaining positions are 2'-methoxy modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 7, 9, 10 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 5, 7 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 3, 7, 8 and 9 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; from 5' to 3', the 2'-fluoro-modified nucleotides are located at positions 2, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides; Alternatively, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 3, 7, 9 and 11 of the sense strand, and the remaining positions are non-fluoro-modified nucleotides; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at positions 2, 7, 10 and 14 of the antisense strand, and the remaining positions are non-fluoro-modified nucleotides.

14. The siRNA according to any one of claims 1 to 13, wherein, in the 5' to 3' direction, the sense strand comprises a phosphorothioate group located at the following positions: Between the first nucleotide and the second nucleotide starting from the 5' end of the sense strand; Between the second nucleotide and the third nucleotide starting from the 5' end of the sense strand; Between the first nucleotide and the second nucleotide starting from the 3' end of the sense strand; Between the second nucleotide and the third nucleotide starting from the 3' end of the sense strand; or, The sense strand contains phosphorothioate groups located at the positions shown below: Between the first nucleotide and the second nucleotide starting from the 5' end of the sense strand; The positive strand is located between the second nucleotide and the third nucleotide starting from the 5' end.

15. The siRNA according to any one of claims 1 to 14, wherein, in the 5' to 3' direction, the antisense strand comprises a phosphorothioate group located at the following positions: Between the first nucleotide and the second nucleotide starting from the 5' end of the antisense strand; Between the second nucleotide and the third nucleotide starting from the 5' end of the antisense strand; Between the first nucleotide and the second nucleotide starting from the 3' end of the antisense strand; The antisense strand is located between the second nucleotide and the third nucleotide starting from the 3' end.

16. The siRNA according to any one of claims 1 to 15, wherein each nucleotide in the sense strand and the antisense strand is independently a 2'-fluoro-modified nucleotide, a 2'-methoxy-modified nucleotide, a GNA-modified nucleotide, a 2'-deoxyribonucleotide or a combination of any two or more thereof; Preferably, in the direction from 5' to 3', the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the direction from 5' to 3', the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the GNA modified nucleotide is located at the 7th position of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the GNA modified nucleotide is located at the 7th position of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 14th and 16th positions of the antisense strand, the GNA modified nucleotide is located at the 6th position of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 14th and 16th positions of the antisense strand, the GNA modified nucleotide is located at the 6th position of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5' phosphate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is not connected to a 5' phosphate group or a 5' phosphate derivative group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is not connected to a 5' phosphate group or a 5' phosphate derivative group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 8th, 9th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th and 14th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 5th, 7th, 8th and 9th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th and 10th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th and 10th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 5th, 8th, 10th, 14th, 16th and 18th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are linked by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified The nucleotides are located at the 2nd, 4th, 6th, 12th, 14th, 16th, 18th and 20th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by phosphorothioate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd and 14th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th and 9th positions of the sense strand, the 2'-deoxyribonucleotide is located at the 11th position of the sense strand, and the remaining positions are 2'-methoxy modified nucleotides, and the 1st nucleotide and the 2nd nucleotide at the 5' end, the 2nd nucleotide and the 3rd nucleotide at the 5' end, the 1st nucleotide and the 2nd nucleotide at the 3' end, and the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by phosphorothioate groups; in the 5' to 3' direction, the 2'-fluoro The nucleotides modified with 2'-methoxy groups are located at the 2nd, 4th, 5th, 6th, 8th, 10th, 12th, 14th, 16th, 18th and 20th positions of the antisense strand, and the remaining positions are 2'-methoxy-modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by phosphorothioate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th and 9th positions of the sense strand, the 2'-deoxyribonucleotide is located at the 11th position of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th, 13th and 15th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 8th, 9th, 10th and 12th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 11th, 13th and 15th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by a thiophosphate group, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by a thiophosphate group, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 11th, 13th and 15th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 9th, 11th and 13th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 11th and 13th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by a thiophosphate group, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by a thiophosphate group, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 11th and 13th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 9th, 11th and 13th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th and 13th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 11th, 12th and 13th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th and 16th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th and 17th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 3rd, 7th, 11th, 16th and 17th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, and the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 6th, 14th and 16th positions of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, and the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 2nd, 3rd, 4th, 5th, 7th, 10th and 14th positions of the antisense strand, the GNA modified nucleotide is located at the 6th position of the antisense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are 2'-methoxy modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups; in the 5' to 3' direction, the 2'-fluoro modified nucleotides are located at the antisense strand The nucleotides at positions 2, 3, 4, 5, 7, 10 and 14 of the strand, the GNA-modified nucleotides at position 6 of the antisense strand, the remaining positions are 2'-methoxy-modified nucleotides, between the first nucleotide and the second nucleotide at the 5' end, between the second nucleotide and the third nucleotide at the 5' end, between the first nucleotide and the second nucleotide at the 3' end, and between the second nucleotide and the third nucleotide at the 3' end are connected by phosphorothioate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinylphosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are non-fluoro-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, the remaining positions are non-fluoro-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 7th, 9th, 10th and 11th positions of the sense strand, the remaining positions are non-fluoro-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 5th, 7th and 14th positions of the antisense strand, the remaining positions are non-fluoro-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 8th and 9th positions of the sense strand, the remaining positions are non-fluoro-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, the remaining positions are non-fluoro-modified nucleotides, the first nucleotide and the second nucleotide at the 5' end, the second nucleotide and the third nucleotide at the 5' end, the first nucleotide and the second nucleotide at the 3' end, the second nucleotide and the third nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group; Alternatively, in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 3rd, 7th, 9th and 11th positions of the sense strand, the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end are connected by thiophosphate groups, and the overhang is removed at the 3' end; in the 5' to 3' direction, the 2'-fluoro-modified nucleotides are located at the 2nd, 7th, 10th and 14th positions of the antisense strand, the remaining positions are non-fluoro-modified nucleotides, between the 1st nucleotide and the 2nd nucleotide at the 5' end, between the 2nd nucleotide and the 3rd nucleotide at the 5' end, between the 1st nucleotide and the 2nd nucleotide at the 3' end, and between the 2nd nucleotide and the 3rd nucleotide at the 3' end are connected by thiophosphate groups, and the 5' terminal nucleotide of the antisense strand is connected to a 5'-trans vinyl phosphonate group.

17. The siRNA according to claim 1, which is selected from the siRNA of Table 1; preferably, the siRNA is selected from N-ER-FY027167, N-ER-FY027167M2, N-ER-FY027167M3, N-ER-FY027167M6, N-ER-FY027167M7, N-ER-FY027167M8, N-ER-FY027167M8D2, N-ER-FY027167M9, N-ER-FY027167M10, N-ER-FY027167M11, N-ER-FY027167M12, N-ER-FY027167M13, N-ER-FY027167M14, N-ER-FY027167M15, N-ER-FY027167M16 ER-FY027186, N-ER-FY027186D2, N-ER-FY027186M2, N-ER-FY027186M3, N-ER-FY027186M4, N-ER-FY0271 86M5、N-ER-FY027186M6、N-ER-FY027186M7、N-ER-FY027186M8、N-ER-FY027186M8D2、N-ER-FY027186M9、 N-ER-FY027186M10, N-ER-FY027186M11, N-ER-FY027186M12, N-ER-FY027186M13, N-ER-FY027186M13D2, N-ER-FY027186M14, N-ER-FY027186M15, N-ER-FY0 27186M15D2、N-ER-FY027186M16、N-ER-FY027186M17、N-ER-FY027186M18、N-ER-FY027186M19、 N-ER-FY027186M20, N-ER-FY027186M21, N-ER-FY027186M21D2, N-ER-FY027186M22, N-ER-FY027186M23, N-ER-FY027186M24, N-ER-FY027186M24D2, N-ER-FY027186M25, N-ER-FY027186M26, N-ER-FY027186M26D2, N-ER-FY027186M27, N-ER-FY027186M27D 2. N-ER-FY027186M28, N-ER-FY027186M29, N-ER-FY027186M29D2, N-ER-FY027186M30, N-ER-FY027186M31, N-ER-FY027186M32, N-ER-FY027186M33, N-ER-FY027186M34, N-ER-FY027186M35, N-ER-FY027186M35D2, N-ER-FY027186M37, N-ER-FY027186M40, N-ER-FY027186M44, N-ER-FY027186M45.

18. An siRNA conjugate, comprising the siRNA according to any one of claims 1 to 17 and a conjugation group conjugated to the siRNA.

19. The siRNA conjugate according to claim 18, wherein the conjugated group comprises a pharmaceutically acceptable targeting group and a linker, and the siRNA, the linker and the targeting group are sequentially covalently or non-covalently linked; Preferably, in the siRNA conjugate, the sense strand and the antisense strand of the siRNA are complementary to each other to form a double-stranded region of the siRNA conjugate, and the 3' end of the sense strand forms a blunt end, and the 3' end of the antisense strand has 1-3 protruding nucleotides extending out of the double-stranded region; or, In the siRNA conjugate, the sense strand and the antisense strand of the siRNA are complementary to each other to form a double-stranded region of the siRNA conjugate, and the 3' end of the sense strand forms a blunt end, while the 3' end of the antisense strand forms a blunt end.

20. The siRNA conjugate according to claim 19, wherein the conjugated group is selected from:

21. The siRNA conjugate according to any one of claims 18 to 20, wherein the siRNA conjugate is a siRNA conjugate selected from Table 2, preferably, the siRNA conjugate is selected from N-ER-FY027167M6L96, N-ER-FY027167M7L96, N-ER-FY027167M8L96, N-ER-FY027167M9L96, N-ER-FY027186M6L96, N-ER-FY027186M7L96, N-ER-FY027186M8L96, N-ER-FY027186M9L96, N-ER-FY027186M10L96, N-ER-FY027186M11L96, N-ER-FY027186M12L96, N-ER-FY027186M13L96, N-ER-FY027186M14L96, N-ER-FY027186M15L96, N-ER-FY027186M16L96, N-ER-FY027186M17L96, N-ER-FY027186M18L96, N-ER-FY027186M19L96, N-ER-FY027186M20L96, N-ER-FY027186M21L96, N-ER-FY027186M22L96, N-ER-FY027186M23L96, N-ER-FY027186M24L96, N-ER-FY027186M25L96, N-ER-FY027186M26L96, N-ER-FY027186M27L96, N-ER-FY027186M28L96, N-ER-FY027186M29L96, N-ER-FY027186M30L96, N-ER-FY027186M31L96, N-ER-FY027186M32L96, N-ER-FY027186M33L96, N-ER-FY027186M34L96, N-ER-FY027186M35L96, N-ER-FY027186M37L96, N-ER-FY027186M40L96, N-ER-FY027186M44L96, N-ER-FY027186M45L96.

22. A pharmaceutical composition comprising the siRNA according to any one of claims 1 to 17, or the siRNA conjugate according to any one of claims 18 to 21, and a pharmaceutically acceptable carrier.

23. A kit comprising the siRNA according to any one of claims 1 to 17, or the siRNA conjugate according to any one of claims 18 to 21, or the pharmaceutical composition according to claim 22.

24. Use of the siRNA according to any one of claims 1 to 17, or the siRNA conjugate according to any one of claims 18 to 21, or the pharmaceutical composition according to claim 22 for preparing a medicament for inhibiting SMAD3 gene expression.

25. Use of the siRNA according to any one of claims 1 to 17, or the siRNA conjugate according to any one of claims 18 to 21, or the pharmaceutical composition according to claim 22 for preparing a medicament for preventing and / or treating diseases associated with SMAD3 gene overexpression.

26. The use according to claim 25, wherein the disease is non-alcoholic fatty liver disease, alcohol-related fatty liver disease, non-alcoholic steatohepatitis, cirrhosis, liver fibrosis, pulmonary fibrosis, vascular fibrosis, glomerulosclerosis and interstitial fibrosis and cancer, in particular ovarian cancer.

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