Use of a polypeptide sjmhe1 thermosensitive hydrogel in the treatment of psoriasis

Abstract

The application provides application of a polypeptide SJMHE1 temperature-sensitive hydrogel in a psoriasis medicine, and is a new use of the polypeptide SJMHE1. The polypeptide SJMHE1 temperature-sensitive hydrogel has the reversible sol-gel conversion characteristics under temperature stimulation, and the temperature-sensitive hydrogel can uniformly cover irregular skin lesions of psoriasis in a sol state, and then continuously adhere and reside on the skin surface in a gel state. The effect of the polypeptide SJMHE1 temperature-sensitive hydrogel on inhibiting skin inflammation of a psoriasis sample mouse is not inferior to even better than that of betamethasone commonly used for treating psoriasis, and the polypeptide SJMHE1 temperature-sensitive hydrogel has smaller side effects than betamethasone. The polypeptide SJMHE1 temperature-sensitive hydrogel is cheap and easy to obtain, and a dosage form is safe.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical technology, specifically to the application of a polypeptide SJMHE1 thermosensitive hydrogel in a drug for treating psoriasis. Background Technology

[0002] Psoriasis is an immune-mediated chronic inflammatory skin disease affecting approximately 3% of the global population. It is primarily characterized by scaly, erythematous plaques. The WHO reports that the incidence of psoriasis is increasing annually, with the incidence in China nearly quadrupling in the past 20 years. The pathogenesis of psoriasis is complex, characterized by a polygenic genetic background and psychological stress, leading to abnormal T-lymphocyte phenotype and function, secretion of various inflammatory cytokines, induction of excessive proliferation of epidermal keratinocytes, and chronic inflammatory responses during their interaction with immune cells. Furthermore, psoriasis is a systemic inflammatory disease that can manifest as complications beyond skin symptoms. Psoriasis can be associated with arthritis, metabolic syndrome, non-alcoholic fatty liver disease, cardiovascular disease, and inflammatory bowel disease. Currently, the main medications for psoriasis include topical preparations of corticosteroids, retinoids, synthetic vitamin D3 analogs, tar, or anthralin; systemic medications such as immunosuppressants, calcineurin inhibitors, acitretin, and isotretinoin; and photochemotherapy (PUVA) and UVB irradiation. The effects of these treatments are short-lived and difficult to prevent relapse. Furthermore, most psoriasis treatments are unsuitable for long-term use due to significant side effects and high costs. Therefore, there is an urgent need to seek new specific targets or new interventions to treat psoriasis patients. Research into developing drugs with low toxicity that can effectively treat psoriasis and their mechanisms of action will not only have significant social benefits but will also generate substantial economic benefits.

[0003] In recent years, the "hygiene hypothesis" has suggested that the significantly increased incidence of allergic and autoimmune diseases in developed Western countries is due to a reduced chance of infection during childhood. Throughout the long history of co-evolution between humans and pathogens, pathogens have evolved various mechanisms to regulate the host's immune regulatory network. Increasing evidence suggests that microbial infections, especially worm infections, can prevent autoimmune and inflammatory diseases. *Science* reported that feeding mice with inflammatory bowel disease (IBD) with *Trichurismuris* and *Heligmosomoides polygyrus* prevented intestinal inflammation. Therefore, worm infection or the development of worm-derived immunomodulatory molecules has become a research hotspot in recent years. However, most of the currently identified worm-derived immunomodulatory molecules are mixtures or macromolecules, with potential immunogenic side effects. The applicant's previous research found that the 24-amino acid small molecule peptide SJMHE1, derived from Schistosoma japonicum eggs and adult antigens, induces CD4+CD25+Treg cells in a TLR2-dependent manner; it can inhibit delayed-type hypersensitivity reactions, joint inflammation, asthma, acute and chronic colitis, and allergic rhinitis in mice; moreover, SJMHE1 can induce M2 macrophages and promote the repair of peripheral nerve damage. However, there are no reports, domestically or internationally, on the use of SJMHE1 peptide for the treatment of psoriasis. Although the small molecule peptide SJMHE1 can avoid the various drawbacks and immunogenicity problems of worm infection, worm secretions, or full-length proteins, peptide drugs also have limitations, including low oral bioavailability, low plasma stability, and short circulation time. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides for the first time an application of the peptide SJMHE1 thermosensitive hydrogel in a drug for treating psoriasis, representing a novel use for the peptide SJMHE1.

[0005] The SJMHE1 thermosensitive hydrogel of this invention exhibits reversible sol-gel transformation properties under temperature stimulation. Furthermore, in its sol state, the thermosensitive hydrogel can uniformly cover irregular psoriatic lesions, and in its gel state, it continuously adheres to and remains on the skin surface. The SJMHE1 thermosensitive hydrogel of this invention demonstrates an inhibitory effect on psoriasis-like skin inflammation in mice that is comparable to, or even superior to, commonly used betamethasone for treating psoriasis, but with fewer side effects. The SJMHE1 thermosensitive hydrogel of this invention is inexpensive, readily available, and has a safe dosage form, providing a new direction for psoriasis treatment.

[0006] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0007] Application of a polypeptide SJMHE1 thermosensitive hydrogel in a drug for treating psoriasis.

[0008] The amino acid sequence of the SJMHE1 polypeptide is shown in SEQ ID NO:1.

[0009] In the above scheme, the SJMHE1 polypeptide is derived from the egg or adult antigen of Schistosoma japonicum, and consists of 24 amino acids, the amino acid sequence of which is shown in SEQ ID NO:1:

[0010] VPGGGTALLRCIPVLDTLSTKNED(Val ProGlyGlyGlyGlyThr AlaLeuLeuArgCys IleProVal Leu Asp ThrLeuSerThr Lys AsnGlu Asp).

[0011] In the above scheme, the drug includes the polypeptide SJMHE1 and excipients.

[0012] Furthermore, the excipients include Freund's incomplete adjuvant, PBS, and poloxamer 407.

[0013] A thermosensitive hydrogel containing the polypeptide SJMHE1, wherein the polypeptide SJMHE1 is used in a drug for treating psoriasis.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] This invention demonstrates through a series of experiments that the peptide SJMHE1 thermosensitive hydrogel alleviates imiquimod (IMQ)-induced skin lesions and PASI scores in psoriasis-like mice, reduces pathological changes in dorsal skin lesions, decreases epidermal thickening, parakeratosis, and hyperkeratosis, and reduces inflammatory cell infiltration in the dermis; reduces the number of Ki67-positive cells per millimeter of basement membrane in the epidermis; lowers the spleen index in psoriasis-like mice; downregulates the expression of pro-inflammatory cytokines IL-6, IL-17A, and TNF-α mRNA in the skin tissue of psoriasis-like mice, and upregulates the expression of anti-inflammatory cytokine IL-10 mRNA; and reduces the expression of p-p65 and p-STAT3 in the skin tissue of psoriasis-like mice. The effect of the peptide SJMHE1 thermosensitive hydrogel in inhibiting skin inflammation in psoriasis-like mice is comparable to or even superior to betamethasone (which is mainly used for stable plaque psoriasis in adults suitable for topical treatment), but it has fewer side effects than betamethasone. Furthermore, the SJMHE1 thermosensitive hydrogel is inexpensive, readily available, and safe in formulation, providing a new direction for the treatment of psoriasis. Attached Figure Description

[0016] Figure 1 The effect of the peptide SJMHE1 thermosensitive hydrogel on imiquimod-induced psoriasis-like skin lesions and PASI scores in mice was investigated. Figure 1A is a flowchart of the treatment of a psoriasis-like mouse model with peptide SJMHE1 thermosensitive hydrogel. Figure 1 B is a representative image of the back skin of mice during the IMQ group modeling process; Figure 1 C is a representative image of the skin on the back of each group of mice before they were sacrificed on day 8; Figure 1 DG represents the PASI score of the dorsal skin lesions of mice in each group (* compares the IMQ+gel group and the IMQ+SJMHE1-gel group); Figure 1 H represents the change in body weight of mice during the modeling process (* compares the IMQ+SJMHE1-gel group with the IMQ+Betamethasone group).

[0017] Figure 2 The effect of the peptide SJMHE1 thermosensitive hydrogel on the histological characteristics of imiquimod-induced psoriasis-like skin lesions in mice was investigated. Figure 2 A shows representative HE staining images of skin lesions on the backs of mice in each group (scale bar: 200 μm); Figure 2 B represents the thickness of the dorsal skin lesions in each group of mice (n=18) ****: p<0.0001.

[0018] Figure 3 The effect of the SJMHE1 thermosensitive hydrogel on Ki67 expression in imiquimod-induced psoriasis-like mouse skin lesions was investigated. Figure 3 A shows representative images of Ki67 staining on the skin lesions on the backs of mice in each group (scale bar: 200 μm); Figure 3 B represents the number of Ki67-positive cells in each group of mice (n=18); ****: p<0.0001.

[0019] Figure 4 The effect of the peptide SJMHE1 thermosensitive hydrogel on imiquimod-induced splenomegaly in psoriasis-like mice; Figure 4 A shows a representative image of the spleen of mice in each group on day 8 (scale bar: 200μm); Figure 4 B represents a comparison of spleen indices among the groups of mice (n=18); ****: p<0.0001.

[0020] Figure 5 The effect of the SJMHE1 thermosensitive hydrogel on the expression of IL-6, IL-17A, TNF-α and IL-10 mRNA in mouse skin lesions was investigated (n=18). Figure 5 A represents the effect of IL-6 expression. Figure 5 B represents the effect of IL-17A expression. Figure 5 C represents the effect of TNF-α expression. Figure 5 D represents the effect of IL-10 mRNA expression. ****: p<0.0001, ***: p<0.001, **: p<0.01, NS: p>0.05.

[0021] Figure 6 The effect of the SJMHE1 thermosensitive hydrogel on the expression of p-p65 and p-STAT3 proteins in mouse skin lesions was investigated. Figure 6 A shows the Western blot images of p-p65 and p-STAT3 proteins; Figure 6 B represents the expression level of p-p65 protein in the skin lesion tissue of mice in each group (n=18); Figure 6 C represents the expression level of p-STAT3 protein in the skin lesions of mice in each group (n=18). Detailed Implementation

[0022] The terminology used in this invention, unless otherwise specified, generally has the meanings commonly understood by those skilled in the art. The invention is further described in detail below with reference to specific embodiments and data. It should be understood that these embodiments are merely illustrative and not intended to limit the scope of the invention in any way. Unless otherwise specified, the reagents, materials, etc., used in the following embodiments are commercially available.

[0023] It should be further noted that the peptide SJMHE1 was synthesized by Shanghai Qiangyao Biotechnology Co., Ltd., and the mice were provided by the Experimental Animal Center of Jiangsu University.

[0024] Example 1: Preparation of thermosensitive hydrogel of peptide SJMHE1

[0025] The SJMHE1 thermosensitive hydrogel was prepared by mixing Freund's incomplete adjuvant, SJMHE1, PBS, and poloxamer 407. The amount of thermosensitive hydrogel used per mouse was 200 μl, and the amount of SJMHE1 was 20 μg. The 200 μl SJMHE1 thermosensitive hydrogel was prepared by mixing 20 μl SJMHE1, 80 μl PBS, 100 μl Freund's incomplete adjuvant, and 20 mg poloxamer 407. After preparation, the mixture was thoroughly mixed using a low-temperature shaker to ensure complete dissolution of poloxamer 407 and complete emulsification of SJMHE1. Meanwhile, a blank thermosensitive hydrogel was set as a control. 200 μl of the blank thermosensitive hydrogel was prepared according to the ratio of 100 μl PBS, 100 μl Freund's incomplete adjuvant and 20 mg poloxamer 407. The preparation process should be kept at low temperature to prevent the activity of SJMHE1 from decreasing and the thermosensitive hydrogel from gelling due to temperature rise.

[0026] Example 2: Construction and experimental grouping of a mouse psoriasis model

[0027] (1) Model construction and grouping:

[0028] Thirty 6-8 week old female BALB / c mice were randomly divided into 5 groups: Control group (blank control group): no treatment; Psoriasis (IMQ) model group: 62.5 mg of imiquimod (IMQ) cream (Sichuan Mingxin Lidi Pharmaceutical Co., Ltd.) was applied to the shaved area on the back of each mouse daily; IMQ + Betamethasone group: 62.5 mg of imiquimod (IMQ) cream was applied to the shaved area on the back of each mouse daily, followed by 50 mg of betamethasone cream (MATTHEW) 6 hours later in the same area. DOCTOR); IMQ+gel (IMQ+hydrogel) group: 62.5 mg of imiquimod (IMQ) cream was applied to the shaved area on the back of each mouse daily, followed by 200 μl of blank thermosensitive hydrogel 6 hours later; IMQ+SJMHE1-gel group: 62.5 mg of imiquimod (IMQ) cream was applied to the shaved area on the back of each mouse daily, followed by 200 μl of peptide SJMHE1 thermosensitive hydrogel 6 hours later. Six mice were in each group. After two days of normal dietary adaptation, the back hair of the mice was shaved using a hair removal device, covering an area of ​​approximately 2 cm × 3 cm. After shaving, depilatory cream was applied to remove the vellus hair. A few minutes later, the remaining hair and depilatory cream were washed away with saline and cotton swabs. 24 hours later, each group underwent the same intervention for 7 consecutive days, receiving a normal diet and alternating light and dark conditions.

[0029] Example 3: Mouse skin lesion recording, PASI score and weight recording

[0030] During the 7-day modeling process, the skin lesions on the backs of the mice were observed and photographed daily, and each mouse was weighed and its weight was recorded. The skin lesions on the backs of the mice were scored daily according to the Psoriasis Area and Severity Index (PASI) scoring system, and a line graph was plotted to compare the severity of the skin lesions in each group. The severity of erythema, scales, and thickening at the lesion site was assigned a score from 0 to 4, and the three scores were summed to obtain the total score. The scoring criteria are as follows: 0, none; 1, mild; 2, moderate; 3, severe; 4, very severe. The specific scoring criteria are shown in Table 1 below.

[0031] Table 1 Scoring Criteria

[0032]

[0033]

[0034] The results are as follows Figure 1As shown, where, Figure 1 Figure A shows the flowchart of the treatment of a psoriasis-like mouse model with the SJMHE1 thermosensitive hydrogel peptide; Figure B shows a representative image of the back skin of mice in the IMQ group during the modeling process; Figure C shows representative images of the back skin of mice in each group before sacrifice on day 8; Figure DG shows the PASI scores of the back skin lesions of mice in each group (* compares the IMQ+gel group and the IMQ+SJMHE1-gel group); Figure H shows the weight changes of mice in each group during the modeling process (* compares the IMQ+SJMHE1-gel group and the IMQ+Betamethasone group). It can be seen that the skin on the exposed areas of the back of mice in the Control group was smooth, without erythema, scaling, or thickening. Mice in the IMQ and IMQ+gel groups showed the above symptoms on their backs, while the inflammation of the back skin lesions in the IMQ+SJMHE1-gel group was alleviated, and the above symptoms were improved. PASI score results showed that mice in the Control group had no skin lesions and a PASI score of zero. The PASI score of mice in the IMQ group gradually increased and was significantly higher than that of the Control group, while the IMQ+gel group showed a similar trend. Although the PASI score of mice in the peptide SJMHE1 thermosensitive hydrogel (IMQ+SJMHE1-gel) group also showed a daily increasing trend, it was significantly lower than that of the IMQ+gel group. This indicates that the peptide SJMHE1 thermosensitive hydrogel can significantly improve the skin lesions in mice. The body weight of mice in the control group tended to stabilize, while the body weight of mice in the IMQ+Betamethasone group generally showed a daily decreasing trend. The body weight of mice in the other groups showed a trend of first decreasing and then increasing. Compared with the IMQ+Betamethasone group, the body weight of mice in the IMQ+SJMHE1-gel group gradually increased from the third day, and on the eighth day, among the four groups other than the control group, the body weight of mice in the IMQ+SJMHE1-gel group was the highest. This indicates that the peptide SJMHE1 thermosensitive hydrogel has fewer side effects than betamethasone, and its intervention effect is no less than or even better than betamethasone.

[0035] Example 4: Hematoxylin-eosin (HE) staining of mouse skin tissue

[0036] After blood was collected from the eyeballs of mice, they were euthanized by cervical dislocation. Skin tissue from the lesion on the back of the mice was carefully excised and fixed in 4% paraformaldehyde for 24-48 hours to fix cells and protect tissue structure. The fixed skin tissue samples were then subjected to stepwise dehydration and clearing with ethanol to remove water and lipids. The dehydrated and defatted skin tissue samples were then embedded in molten paraffin and frozen into paraffin blocks for later use. The paraffin-cured tissue samples were then cut into thin sections with a thickness of approximately 3-5 μm using a tissue sectioner. The cut tissue sections were placed on glass slides and baked in an oven until the paraffin was completely melted. The baked sections were then quickly immersed in xylene twice, 5 minutes each time. The sections were then placed in 100%, 90%, 80%, and 70% ethanol for 5 minutes each, followed by 5 minutes in distilled water. After the water was absorbed, hematoxylin staining solution was added and stained for 5 minutes. The hematoxylin staining solution was then rinsed off with running water, and the staining degree was observed under a microscope. Differentiate with 1% hydrochloric acid-ethanol for 1-3 seconds, rinse with running water, and then soak in distilled water for 5-10 minutes to regain blue color. Observe the staining under a microscope. If the color is too light, add hematoxylin staining solution for another minute, differentiate again, and immediately rinse with water. If the color is too dark, appropriately increase the differentiation time. Add one drop of 0.5% eosin staining solution and stain for 10-15 seconds. Rinse with distilled water and observe the staining under a microscope. Dehydrate the sections sequentially with 80%, 90%, 95%, and 100% ethanol, then immerse them in xylene twice, 5 minutes each time. Allow the xylene on the surface of the sections to air dry at room temperature, then add one drop of neutral resin and gently place a coverslip on top to seal. After air drying for 24 hours, observe under an imaging microscope and take pictures of randomly selected fields of view. Results are as follows. Figure 2 middle Figure 2 As shown in Figure A, the control group mice had thin skin. Compared with the control group mice, the IMQ group mice exhibited typical psoriasis skin manifestations such as significantly thickened epidermis, hyperkeratosis with parakeratosis, increased number of spinous cells extending downwards in a club-like pattern, inflammatory cell infiltration in the dermis, local telangiectasia, and Munro microabscesses. The IMQ+gel group showed the same manifestations. Compared with the IMQ+gel group, the pathological changes of the skin lesions on the back of mice in the peptide SJMHE1 thermosensitive hydrogel (IMQ+SJMHE1-gel) group were reduced, the epidermis was significantly thinner, parakeratosis and hyperkeratosis were reduced, acanthosis was significantly improved, and the degree of inflammatory cell infiltration in the dermis was reduced. Figure 2 Quantitative analysis showed that the epidermal thickness of mice in the IMQ+SJMHE1-gel group was significantly lower than that in the IMQ+gel group.

[0037] Example 5: Ki67 Immunohistochemistry (IHC) Staining

[0038] Mouse skin tissue samples were dehydrated and defatted, paraffin-embedded and sectioned, dewaxed, and graded hydrated before antigen retrieval using sodium citrate antigen retrieval solution. After retrieval, the samples were blocked with 3% hydrogen peroxide solution in the dark for 30 min to block endogenous catalase. Then, they were blocked with 5% BSA antigen blocking solution at room temperature for 60 min to block the endogenous antigen. After antigen blocking, Ki67 anti-mouse monoclonal antibody was added and incubated overnight at 4°C. The samples were washed three times with PBS, and an appropriate amount of HRP-labeled secondary antibody working solution was added. After incubation at room temperature for 60 min, the samples were washed three times with PBS, and then developed with DAB. The results are as follows: Figure 3 middle Figure 3 As shown in Figure A, compared with the Control group, the number of Ki67-positive cells in the epidermal basement membrane of mice in the IMQ group was significantly increased. Compared with the IMQ+gel group, the expression of Ki67 in the skin of mice in the IMQ+SJMHE1-gel group was significantly decreased. Figure 3 Quantitative analysis of B also showed that the number of Ki67-positive cells per millimeter of basement membrane in mice in the peptide SJMHE1 thermosensitive hydrogel (IMQ+SJMHE1-gel) group was significantly lower than that in the IMQ+gel group. Simultaneously, compared to the IMQ+Betamethasone group, the IMQ+SJMHE1-gel group showed even fewer Ki67-positive cells proliferating in the epidermis. This indicates that the peptide SJMHE1 thermosensitive hydrogel can improve psoriatic lesions by inhibiting keratinocyte proliferation, and that the intervention effect of the peptide SJMHE1 thermosensitive hydrogel is comparable to, and may even be superior to, betamethasone.

[0039] Example 6: Isolation of mouse spleen and detection of spleen index

[0040] Mice were sacrificed on day 8 and immersed in 75% ethanol for 5 minutes. The heads and limbs of the mice were fixed. Under aseptic conditions, the skin and peritoneum were cut open with scissors, and surrounding tissues were bluntly dissected with forceps. The spleen was removed, and residual blood was blotted with filter paper. The spleen was weighed using an analytical balance (mg) and compared with the mouse's body weight (g) to determine the spleen index. Spleen index (mg / g) = spleen weight / mouse body weight. Results are as follows... Figure 4 As shown in Figure A, compared with the Control group, IMQ induction caused significant splenomegaly in the psoriasis model mice. Splenomegaly also occurred in the IMQ+gel group mice. However, after intervention with the peptide SJMHE1 thermosensitive hydrogel, the splenomegaly in the mice was reduced. Figure 4 Quantitative analysis of B also showed that the spleen index of mice in the IMQ+SJMHE1-gel group was significantly lower than that in the IMQ+gel group. Furthermore, compared to the IMQ+Betamethasone group, mice in the IMQ+SJMHE1-gel group had smaller spleens and lower spleen indices.

[0041] Example 7: Cytokine mRNA Expression in Mouse Skin Tissue by Real-Time Quantitative PCR

[0042] Mouse skin tissue was minced and lysed with 1 ml of Trizol using a homogenizer. The mixture was allowed to stand at 15-30°C for 5 min. Then, 200 μl of chloroform was added, shaken for 15 s, and allowed to stand at 15-30°C for 2-3 min. The mixture was then centrifuged at 12000 g for 15 min at 4°C. After centrifugation, the supernatant (approximately 400 μl) was transferred to a new 1.5 ml EP tube. An equal volume of isopropanol (approximately 400 μl) was added, shaken for 15 s, and allowed to stand at 15-30°C for 10 min. The mixture was then centrifuged at 12000 g for 10 min at 4°C, and the supernatant was discarded. The precipitate was then washed with 1 ml of pre-cooled 75% ethanol, and the remaining ethanol was aspirated. The tube was then dried at room temperature for 10-15 min. Then add approximately 20-30 μl of DEPC water to fully dissolve the RNA precipitate, measure the RNA concentration (ng / μl), and after reverse transcription, detect the expression of IL-6, IL-10, IL-17A, and TNF-α mRNA by qRT-PCR. Results are as follows: Figure 5 As shown in the AD diagram, compared with the Control group, the expression levels of IL-6, IL-17A, and TNF-α mRNA in the skin lesions of mice in the IMQ group were increased; compared with the IMQ+gel group, the expression of IL-6, IL-17A, and TNF-α mRNA in the skin lesions of mice in the IMQ+SJMHE1-gel group was decreased, while the expression of IL-10 mRNA was significantly increased. Simultaneously, compared with the IMQ+Betamethasone group, the expression of IL-6, IL-17A, and TNF-α mRNA in the skin of mice in the IMQ+SJMHE1-gel group showed a decreasing trend. This indicates that the SJMHE1 thermosensitive hydrogel can inhibit the expression of inflammatory factors, and the intervention effect of the SJMHE1 thermosensitive hydrogel is comparable to, and may even be superior to, betamethasone.

[0043] Example 8: Western blot (WB) detection of proteins in mouse skin tissue

[0044] Frozen mouse skin tissue was removed from the -80°C freezer, cut to an appropriate size, and placed in a sterile EP tube. 100 μl of RIPA lysis buffer was added, and the skin tissue was thoroughly homogenized using a tissue homogenizer. After homogenization, the tissue was placed on ice for 10 min for lysis. After lysis, the tissue was centrifuged at 12,000 rpm for 5 min at 4°C, and the supernatant was transferred to a new sterile EP tube for protein extraction. The supernatant was mixed with protein loading buffer at a 4:1 ratio, vortexed thoroughly, and then stained. The stained protein solution was then placed in a 100°C metal water bath for 10 min for protein denaturation. The denatured protein was subjected to SDS-PAGE / polyacrylamide gel electrophoresis and transferred to a PVDF membrane. The membrane was then blocked in 5% skim milk at room temperature for 1 h, followed by incubation overnight at 4°C with p-P65, p-STAT3, and GAPDH antibodies. After washing with TBST, the membrane was incubated with horseradish peroxidase-conjugated secondary antibody at room temperature for 1 h. After washing with TBST buffer, the sample was exposed and developed using a high-sensitivity ECL chemiluminescence kit. Figure 6 As shown in AC, the protein expression of p65 and STAT3 in the skin lesions of mice in each group remained unchanged. Compared with the Control group, the expression levels of p-p65 and p-STAT3 in the IMQ group were significantly increased. Compared with the IMQ+gel group, the protein expression of p-p65 and p-STAT3 in the IMQ+SJMHE1-gel group was significantly decreased. However, the expression of p-p65 and p-STAT3 in the skin of mice in the IMQ+Betamethasone group was not different from that in the IMQ group. This suggests that the peptide SJMHE1 thermosensitive hydrogel may function through the NF-κB and STAT3 signaling pathways.

[0045] This invention demonstrates through a series of experiments that the peptide SJMHE1 thermosensitive hydrogel alleviates imiquimod (IMQ)-induced skin lesions and PASI scores in psoriasis-like mice, reduces pathological changes in dorsal skin lesions, decreases epidermal thickening, parakeratosis, and hyperkeratosis, and reduces inflammatory cell infiltration in the dermis; reduces the number of Ki67-positive cells per millimeter of basement membrane in the epidermis; lowers the spleen index in psoriasis-like mice; downregulates the expression of pro-inflammatory cytokines IL-6, IL-17A, and TNF-α mRNA in the skin tissue of psoriasis-like mice, upregulates the expression of anti-inflammatory cytokine IL-10 mRNA; and reduces the expression of p-p65 and p-STAT3 in the skin tissue of psoriasis-like mice. Compared to the positive control group of betamethasone cream (IMQ+Betamethasone), the SJMHE1 thermosensitive hydrogel group (IMQ+SJMHE1-gel) showed lower numbers of Ki67-positive cells proliferating in the epidermis, smaller spleens, lower spleen index, and reduced expression of IL-6, IL-17A, and TNF-α mRNA in the skin. However, the SJMHE1 thermosensitive hydrogel group (IMQ+SJMHE1-gel) gradually increased in weight starting from day 3. On days 6, 7, and 8 after IMQ administration, the weight of mice in the positive control betamethasone group was lower than that in the SJMHE1 thermosensitive hydrogel group, indicating that the positive control betamethasone cream was more toxic to mice. The SJMHE1 thermosensitive hydrogel can reduce the expression of pro-inflammatory cytokines and increase the expression of anti-inflammatory cytokines by inhibiting NF-κB and STAT3 signaling, thereby alleviating IMQ-induced skin inflammation in psoriasis-like mice. Furthermore, the SJMHE1 thermosensitive hydrogel's inhibitory effect on psoriasis-like mouse skin inflammation is comparable to, or even superior to, betamethasone, but with fewer side effects. The SJMHE1 thermosensitive hydrogel is inexpensive, readily available, and has a safe formulation, providing a new direction for psoriasis treatment.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. The application of a polypeptide SJMHE1 thermosensitive hydrogel in the preparation of a drug for treating psoriasis, wherein the amino acid sequence of the polypeptide SJMHE1 is shown in SEQ ID NO:

1.

2. The application of the polypeptide SJMHE1 thermosensitive hydrogel according to claim 1 in the preparation of drugs for treating psoriasis, characterized in that, The drug includes the polypeptide SJMHE1 and excipients.

3. The application of the polypeptide SJMHE1 thermosensitive hydrogel according to claim 2 in the preparation of drugs for treating psoriasis, characterized in that, The excipients include Freund's incomplete adjuvant, PBS, and poloxamer 407.

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