Use of a sucnr1 gene expression inhibitor in the preparation of a medicament for improving heart failure

Abstract

The present application relates to the field of medicine, and particularly relates to application of SUCNR1 gene expression inhibitor in preparation of a drug for improving heart failure. The SUCNR1 gene expression inhibitor comprises a SUCNR1 gene knockout reagent, and the SUCNR1 gene knockout reagent is siRNA. The present application finds that the SUCNR1 expression level is highly expressed in a mouse heart failure model, and the siRNA technology is used to respectively transfect myocardial cells by siRNA, and the siRNA is used to knock down and reduce the SUCNR1 protein level in cells or heart tissues, so as to determine the effect of SUCNR1 on the mouse heart function; the biological information analysis method is used to analyze and predict the target gene participating in the heart mitochondrial function damage which can be regulated by SUCNR1, and then the siRNA is used to knock down the SUCNR1, so as to determine the regulation effect of the siRNA on the downstream gene, and the mechanism is determined, so that the SUCNR1 becomes an important target point for treating heart failure in the heart.

Description

Technical Field

[0001] This invention relates to the pharmaceutical field, specifically to the application of SUCNR1 gene expression inhibitors in the preparation of drugs to improve heart failure. Background Technology

[0002] The heart is a high-energy-demand organ, requiring continuous ATP production to maintain its contractile function. The ATP stored in the heart can only sustain a heartbeat for 2-10 seconds. Mitochondrial oxidative metabolism is the primary energy source for the heart. In a healthy heart, energy is supplied by various energy substrates, with approximately 40%-60% from fatty acid oxidation and 20%-40% from glucose metabolism. However, in a failing heart, energy metabolism changes. Compared to a healthy heart, the ATP content in the end-stage of heart failure decreases by about 30%, leading to insufficient energy supply and ultimately impaired myocardial contractile function. This altered energy metabolism may be due to impaired mitochondrial oxidative metabolism, altered cardiac energy substrate preferences, and reduced cardiac efficiency. Metabolic remodeling plays a crucial role in regulating cardiac energy substrate utilization, ion and redox homeostasis, and maintaining ATP levels, and is essential for maintaining cardiac contractile function. Furthermore, the accumulation of certain metabolites during cardiac metabolic remodeling further exacerbates metabolic disorders. However, the signaling pathways involved in cardiac metabolic remodeling during the pathogenesis of heart failure are highly complex, and the regulatory mechanisms are not yet fully understood; current research is insufficient.

[0003] Succinate is an important intermediate in the tricarboxylic acid cycle, produced by the decarboxylation of α-ketoglutarate via α-ketoglutarate dehydrogenase. Further, succinate is oxidized by SDH to produce fumarate. In addition, succinate metabolism involves branched-chain amino acid metabolism, ketone body metabolism, and heme metabolism. Recent studies have shown that succinate, besides playing a role in multiple cellular metabolic pathways, also participates in various pathophysiological activities. Succinate regulates disease progression mainly through three mechanisms: generating reactive oxygen species (ROS), participating in succinylation modification, and acting on the succinate receptor SUCNR1 to regulate downstream signal transduction. Previous research by the inventors found that succinate levels are significantly elevated in the plasma of patients with aortic dissection, and elevated plasma succinate levels lead to increased ROS levels in the vascular wall, exacerbating aortic dissection; inhibiting the succinate production pathway can alleviate aortic dissection by targeting the p38α-CREB-OGDH axis. In inflammatory macrophages, succinate levels are elevated, and after being oxidized by SDH, a large amount of reactive oxygen species (ROS) is generated, leading to mitochondrial dysfunction and driving increased expression of macrophage inflammatory factors. During myocardial ischemia, succinate accumulates rapidly, and with reperfusion, it is rapidly oxidized to generate large amounts of ROS, leading to cardiomyocyte death and exacerbating ischemia-reperfusion injury. Succinylation is a newly discovered post-translational modification in recent years, and studies suggest that succinylation is involved in various cardiovascular diseases. SIRT5 is a desuccinylase; SIRT5 knockout leads to increased ECHA succinylation levels and decreased ECHA activity in muscle cells, resulting in impaired cardiomyocyte function and hypertrophic cardiomyopathy.

[0004] Succinate can also specifically bind to the succinate receptor 1 (SUCNR1), mediating corresponding signal transduction. SUCNR1 is a G protein-coupled receptor widely expressed in the immune system, nervous system, cardiovascular system, and muscle tissue. According to literature reports, SUCNR1 can bind to Gi or Gq, triggering different pathways and inducing various cellular effects, such as inducing intracellular calcium release, inositol triphosphate formation, ERK1 / 2 activation, and decreased cyclic adenosine monophosphate (cAMP) concentration. In cardiomyocytes, after SUCNR1 activation, through coupling with Gi, it leads to a decrease in intracellular cAMP levels and an increase in intracellular calcium. 2+The instantaneous decrease in magnitude and rate of decrease is increased. In addition, SUCNR1 is involved in various pathological activities. For example, in the tumor microenvironment, increased succinate concentration activates SUCNR1 in macrophages, which, by binding to Gi, activates PI3K, mediating increased Hif-1α expression and leading to macrophage differentiation into tumor-associated macrophages. In platelets, after succinate activates SUCNR1, it binds to Gi, reduces cAMP levels, and activates PI3K / Akt, thereby activating P-selectin and promoting platelet aggregation. In ischemic diseases, such as stroke, SUCNR1 activation promotes angiogenesis by upregulating prostaglandin E2 and initiating the expression of angiogenesis-related genes (VEGF, etc.). Furthermore, the succinate-SUCNR1 pathway also plays an important role in diseases such as bone disorders, intestinal gluconeogenesis, and immune disorders. However, the role of the succinate-SUCNR1 pathway in the development and progression of heart failure has not yet been reported. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide the application of SUCNR1 gene expression inhibitor in the preparation of drugs to improve heart failure.

[0006] The inventors of this application utilized biochemical, molecular biological, and cell biological research methods to discover that SUCNR1 expression levels were elevated in a mouse model of heart failure. Subsequently, using small interfering RNA (SRNA) technology, SRNA was transfected into cardiomyocytes or injected intravenously into the tail vein to knock down PAX4 protein levels in cells or heart tissue, thereby clarifying the role of SUCNR1 in mouse cardiac function. Bioinformatics methods were then used to analyze downstream signaling pathways induced by SUCNR1 activation. Finally, SUCNR1 knockdown using SRNA was used to clarify its regulatory effect on downstream genes, thus elucidating the mechanism of action.

[0007] To achieve this objective, the present invention employs the following technical solution: the application of SUCNR1 gene expression inhibitors in the preparation of drugs to improve heart failure.

[0008] In some embodiments of the present invention, the SUCNR1 gene expression inhibitor includes a SUCNR1 gene knockout reagent.

[0009] In some embodiments of the present invention, the SUCNR1 gene knockout reagent is siRNA, the siRNA sequence is shown in SEQ ID NO:1, and the antisense nucleotide sequence of the siRNA is shown in SEQ ID NO:2.

[0010] In some embodiments of the present invention, SUCNR1 gene expression inhibitors can suppress the increase in SUCNR1 protein levels in mouse heart failure or fibrotic heart tissue.

[0011] In some embodiments of the present invention, the SUCNR1 gene expression inhibitor can suppress the increase in mRNA expression levels of heart failure markers in mouse heart failure tissue, wherein the heart failure markers are ANP, BNP, β-MHC, Ctag, or Acta1.

[0012] In some embodiments of the present invention, the SUCNR1 gene expression inhibitor can suppress the decrease in the expression of mitochondrial functional markers in mouse fibrotic heart tissue, wherein the mitochondrial functional markers are Nudfa11, SDHC, Uqcrb, Cox6a2 or ATP5e.

[0013] In some embodiments of the present invention, SUCNR1 gene expression inhibitors can inhibit the destruction of mitochondrial morphology and dysfunction in mouse fibrotic heart tissue; SUCNR1 gene expression inhibitors can inhibit the damage to mitochondrial function in mouse cardiomyocytes, thereby inhibiting the decrease in oxygen consumption for ATP production and basal respiratory oxygen consumption.

[0014] In some embodiments of the present invention, the SUCNR1 gene expression inhibitor can suppress the increase in protein levels of myofibroblast markers Col I, αSMA, thereby inhibiting fibroblast transdifferentiation.

[0015] In some embodiments of the present invention, the SUCNR1 gene expression inhibitor can reduce the mRNA expression levels of heart failure biomarkers ANP, BNP, β-MHC, Ctag, and Acta1; the SUCNR1 gene expression inhibitor can promote the increase in the expression levels of mitochondrial functional biomarkers, namely Nudfa11, SDHC, Uqcrb, Cox6a2, or ATP5e.

[0016] In some embodiments of the present invention, the SUCNR1 gene expression inhibitor knocks down SUCNR1, thereby inhibiting the transformation of fibroblasts into myofibroblasts and inhibiting the protein expression level of myofibroblast marker Col I and fibronectin.

[0017] The beneficial effects of this invention are as follows: This invention provides a novel application of SUCNR1 as an important new target for the treatment of heart failure; This invention utilizes biochemical, molecular biological, and cell biological research methods to discover that SUCNR1 expression is high in a mouse heart failure model; Using small interfering RNA (SRNA) technology, cardiomyocytes were transfected with SUCNR1, and SUCNR1 protein levels in cells or heart tissues were reduced by SUCNR1 knockdown, thereby clarifying the role of SUCNR1 in mouse cardiac function; Bioinformatics methods were used to analyze and predict target genes involved in the disruption of cardiac mitochondrial function that can be regulated by SUCNR1, and the regulatory effect of SUCNR1 on downstream genes was clarified by SUCNR1 knockdown, thus clarifying the mechanism of action, making SUCNR1 a potentially novel and important target for the treatment of heart failure in the heart. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 Protein imprinting and immunohistochemical analysis revealed the expression level of SUCNR1 during the pathogenesis of heart failure; among which... Figure 1 In the figure, A represents the results of Western blotting analysis of elevated expression levels in the heart tissue of mice with heart failure, along with quantitative statistical analysis. GAPDH was used as an internal control. Figure 1 B in the figure represents the IOD analysis result obtained by immunohistochemistry using SUCNR1 antibody labeling to quantify SUCNR1.

[0020] Figure 2 To verify the expression level of SUCNR1 in cardiomyocytes under angiotensin II stimulation using Western blotting; among which Figure 2 In the figure, A represents the protein level of SUCNR1 detected by Western blot assay after angiotensin stimulation. Figure 2 B in the figure represents the quantitative and statistical analysis results of the SUCNR1 protein content detected by Western blotting.

[0021] Figure 3 To verify by polymerase chain reaction that SUCNR1 activation leads to decreased cardiac function and the expression levels of heart failure markers (ANP, BNP, β-MHC, Ctag, Acta1).

[0022] Figure 4 The graph shows the expression results of mitochondrial functional markers (Nudfa11, SDHC, Uqcrb, Cox6a2, ATP5e) after SUCNR1 activation, as verified by polymerase chain reaction.

[0023] Figure 5 The images are transmission electron microscopy images. After SUCNR1 activation, the morphology of cardiac mitochondria is disrupted, and their function is impaired.

[0024] Figure 6 The image shows the results of the seahorse experiment verifying the impairment of mitochondrial function in cardiomyocytes after SUCNR1 activation.

[0025] Figure 7 A representative image of Western blot analysis of the myofibroblast markers Col I and αSMA after SUCNR1 activation. Figure 7 A) and the results of quantitative and statistical analysis of protein content ( Figure 7 B).

[0026] Figure 8 To verify the mRNA expression levels of heart failure markers ANP, BNP, β-MHC, Ctag, and Acta1 after SUCNR1 knockout using polymerase chain reaction.

[0027] Figure 9 To detect the expression of mitochondrial functional markers (Nudfa11, SDHC, Uqcrb, Cox6a2, ATP5e) after SUCNR1 knockdown using polymerase chain reaction.

[0028] Figure 10 A representative image of Western blot analysis of Col I and αSMA after SUCNR1 knockdown (for protein blotting). Figure 10 A) and the results of quantitative and statistical analysis of protein content ( Figure 10 B). Detailed Implementation

[0029] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0030] Experimental methods in the following examples that do not specify specific conditions were performed in accordance with standard practices in the relevant field or under conditions recommended by the manufacturer.

[0031] Animal pathological model experiment: A mouse heart failure model was constructed. Heart tissue was collected, and the location and content of SUCNR1 protein expression, as well as the content of heart failure markers ANP, BNP, β-MHC, Ctag, and Acta1, were detected using immunohistochemistry and protein imprinting experiments.

[0032] Experimental materials: Preparation of aortic arch coarctation (TAC) induced mouse heart failure model: 10-week-old male C57BL / 6 mice were randomly divided into two groups, the surgical group and the sham-operated group. The mice were used to construct a heart failure model by aortic arch coarctation with a 27G needle for 8 weeks.

[0033] The experimental method for SUCNR1 immunohistochemistry: The sample was fixed in paraformaldehyde, embedded in paraffin, and then cut. The specific operation steps are as follows:

[0034] (1) Dewaxing: The tissue sections were treated with xylene for 15 min 3 times, 100% ethanol for 5 min 2 times, 95% ethanol for 5 min 2 times, 80% ethanol for 5 min 1 time, and finally washed with distilled water for 2 min.

[0035] (2) Removal of endogenous catalase: Place the slices in 3% hydrogen peroxide solution (prepared with 100% methanol) for 10-15 min to remove endogenous catalase, and then wash with PBS 3 times for 5 min each time.

[0036] (3) Antigen heat retrieval: Place the slides in citrate (pH 6.0) antigen retrieval solution and perform heat retrieval in an autoclave to fully develop the antigen epitopes (wait for 2 minutes after the autoclave starts releasing steam continuously). After heat retrieval, place the slides at room temperature and wash them three times with PBS for 5 minutes each time when the slide temperature drops to room temperature.

[0037] (4) Serum blocking: Place the slide in a humidified chamber and block with 10% goat serum at room temperature for 30 minutes.

[0038] (5) Primary antibody incubation: After discarding the serum, add the prepared primary antibody to the slide and incubate overnight at 4°C (or incubate for 2 hours at 37°C).

[0039] (6) Secondary antibody incubation: Remove the humidified box from the 4℃ refrigerator, cool it to room temperature, and wash it three times with PBS for 5 min each time. Then add horseradish peroxidase-labeled secondary antibody (Zhongshan Jinqiao Company, rabbit two-step method) and incubate at room temperature for 30 min.

[0040] (7) DAB color development: Wash 3 times with PBS and then perform color development using DAB color development solution. Preparation method of DAB working solution: 1 mL DAB diluent + 50 μL DAB color development solution.

[0041] (8) Counterstaining nuclei: First soak in distilled water for 2 minutes, then put in hematoxylin solution for 30 seconds, rinse 3 times with tap water; differentiate in 70% hydrochloric acid alcohol for 5-6 seconds, wash with water for 30 seconds; return to blue in 1% ammonia water for 60 seconds, and wash away the floating color in distilled water (the nuclei can be observed under a microscope to see if they have been stained blue).

[0042] (9) Dehydrate, clear, and mount with neutral resin mounting medium; 95% ethanol for 2 min twice, anhydrous ethanol for 2 min twice, and finally xylene substitute for 5 min twice.

[0043] (10) Scan the film after it has dried and use software to count the positive area.

[0044] Extraction of total protein from myocardial tissue: Myocardial tissue preserved in liquid nitrogen was ground in a mortar with liquid nitrogen. Two-thirds of the ground tissue (the other one-third was used to extract RNA) was added to tissue lysis buffer (20 mmol / L Tris-HCl pH 7.4, 150 mmol / L NaCl, 2.5 mmol / L EDTA, 50 mmol / L NaF, 0.1 mmol / L Na4P2O7, 1 mmol / L Na3VO4, 1% Triton X-100, 10% glycerol, 0.1% SDS, 1% deoxycholic acid, 1 mmol / L LMSF, 1 μg / mL aprotinin). After mixing, the mixture was placed on ice for 15 minutes. Approximately 800 μL of lysis buffer was added for every 50 mg of myocardial tissue. Collect the homogenate, sonicate it (45%, turn on for 5 seconds, turn off for 5 seconds, repeat 4 times), centrifuge at 12000 rpm for 15 minutes at 4℃, transfer a portion of the supernatant to a new EP tube, quantify the protein, freeze at -80℃, add a quarter volume of 5X loading buffer to a portion of the supernatant, mix well, boil at 100℃ for 5 minutes, freeze, and reserve for subsequent protein blot detection of related proteins.

[0045] Western blot assay: After electrophoresis with 10% SDS-PAGE gel, nitrocellulose membranes were transferred and blocked with 5% skim milk at room temperature for 1 hour. The membranes were then incubated overnight at 4°C with primary antibodies: fibronectin (ab2413, abcam, Cambridge, MA, USA), αSMA (ab32575, abcam, Cambridge, MA, USA), ColI (203002, MDBiosciences), SUCNR1 (ab75105, abcam, Cambridge, MA, USA), and GAPDH (2118S, CST). The membranes were washed three times with TBST, then with the corresponding species-specific secondary antibody for 1 hour at room temperature. After another TBST wash, the membranes were developed and placed in developing solution (Millipore Corporation). The membranes were then drained and exposed using a chemiluminescence immunoassay analyzer. Band intensity was quantified using NIH ImageJ software.

[0046] Aortic arch coarctation was performed, and a mouse heart failure model was established using 10-week-old male C57BL / 6 mice. The expression level of SUCNR1 in the heart tissue of the heart failure model was detected, and the severity of heart failure was detected by biomarkers corresponding to the mice.

[0047] The experimental materials used in Examples 1-6 below were all mouse body tissues that had been treated as described above.

[0048] Example 1: Heart tissues from mice in the heart failure model constructed using the above-mentioned aortic arch coarctation (TAC) surgery and the sham-operated group were used for immunohistochemical experiments using the SUCNR1 antibody. The experimental results are as follows: Figure 1 As shown.

[0049] Protein imprinting and immunohistochemical analysis revealed that SUCNR1 expression levels increased during the pathogenesis of heart failure; among which... Figure 1 In the figure, A represents the results of Western blotting analysis of elevated SUCNR1 expression levels in heart tissue of mice with heart failure and quantitative statistical analysis. GAPDH was used as an internal control. In heart tissue of mice with heart failure, the protein level of SUCNR1 increased. Statistical analysis of the quantitative results showed that the protein level of SUCNR1 in fibrotic heart tissue was significantly increased compared with the protein level of PAX4 in heart tissue of healthy mice.

[0050] Figure 1 B in the figure represents the IOD analysis results of SUCNR1 quantification using SUCNR1 antibody labeling by immunohistochemistry. The results show that the expression level of SUCNR1 is significantly increased in the heart tissue of mice with heart failure.

[0051] The expression level of SUCNR1 after Ang II stimulation at the cellular level was detected by Western blotting. The results showed that the expression level of SUCNR1 increased under the stimulation of angiotensin II in cardiomyocytes. Figure 2 In the figure, A represents the protein level of SUCNR1 detected by Western blot assay after angiotensin stimulation. Figure 2 B in the figure represents the quantitative and statistical analysis results of the SUCNR1 protein content detected by Western blotting.

[0052] Example 2: Detection of the expression levels of heart failure markers after SUCNR1 activation following TAC surgery in mice.

[0053] Aortic arch coarctation was performed, and a mouse model of heart failure was established using 10-week-old male C57BL / 6 mice. SUCNR1 was activated using 1.5% succinate, and the severity of heart failure was assessed by detecting biomarkers corresponding to different levels of heart failure in the mice. The experimental results are as follows: Figure 3 As shown. Figure 3 The results showed that polymerase chain reaction (PCR) confirmed that after SUCNR1 activation, the mRNA expression levels of heart failure markers ANP, BNP, β-MHC, Ctag, and Acta1 increased significantly, indicating decreased cardiac function and exacerbating TAC-induced heart failure in mice.

[0054] Polymerase chain reaction (PCR) confirmed that SUCNR1 activation disrupted cardiac mitochondrial function, leading to decreased expression levels of mitochondrial functional markers (Nudfa11, SDHC, Uqcrb, Cox6a2, ATP5e). The results are as follows: Figure 4 As shown.

[0055] Transmission electron microscopy confirmed that SUCNR1 activation disrupts the morphology and dysfunction of cardiac mitochondria. Transmission electron microscopy images showed that after SUCNR1 activation, cardiomyocyte mitochondria swelled, the inner cristae disappeared, and their function was impaired. The results are as follows: Figure 5 As shown.

[0056] Example 3: Using primary cardiac cardiomyocytes from suckling mice, the mitochondrial function of the cardiomyocytes was detected by the Seahorse assay after treating the cells with 10 μM succinic acid for 2 days.

[0057] Cardiomyocytes were uniformly seeded in Seahorse cell culture microplates and stimulated with isoproterenol (ISO). After 48 hours, the cell culture microplates were placed in an Agilent Seahorse XFe24 instrument to measure cellular oxygen consumption and observe the effect of SUCNR1 activation on mitochondrial function. The results are as follows: Figure 6 As shown.

[0058] Figure 6 The results showed that SUCNR1 activation impaired mitochondrial function in cardiomyocytes, indicating a significant disruption in mitochondrial function. Seahorse experiments verified that succinate, as a ligand for SUCNR1, activated SUCNR1, leading to a decrease in mitochondrial maximal oxygen consumption, idle oxygen consumption, ATP production oxygen consumption, and basal oxygen consumption in cardiomyocytes.

[0059] Example 4: Using cardiac fibroblasts, after treating the cells with 10 μM succinic acid for 2 days, under the stimulation of AngII, it was verified that SUCNR1 activation promotes the transformation of fibroblasts into myofibroblasts.

[0060] Primary fibroblasts were extracted from adult mice and stimulated with cellular angiotensin II (Ang II). Succinate was simultaneously administered to activate SUCNR1. After 48 hours, Western blotting was used to detect markers of fibroblast transdifferentiation (col1a1, SMA). The results are as follows: Figure 7 As shown. Figure 7 The results showed that Western blot analysis revealed increased protein levels of myofibroblast markers Col I and αSMA after SUCNR1 activation, indicating enhanced fibroblast transdifferentiation.

[0061] Example 5: Polymerase chain reaction (PCR) verification that SUCNR1 knockout protects cardiac function, alleviates heart failure, reduces the expression of heart failure markers, and protects mitochondrial function. PCR testing after aortic arch coarctation (TAC) showed that SUCNR1 knockout reduced the mRNA levels of heart failure markers ANP, BNP, β-MHC, Ctag, and Acta1, as shown in the results. Figure 8 As shown.

[0062] Polymerase chain reaction (PCR) analysis showed that after aortic arch coarctation (TAC), the expression levels of mitochondrial functional markers (Nudfa11, SDHC, Uqcrb, Cox6a2, ATP5e) increased, protecting cardiomyocyte mitochondrial function. The results were as follows: Figure 9 As shown.

[0063] Example 6: Using cardiac fibroblasts, SUCNR1 was knocked down with small interfering RNA. After 48 hours, under AngII stimulation, it was verified that SUCNR1 knockdown inhibited the transformation of fibroblasts into myofibroblasts. The results are as follows: Figure 10 As shown.

[0064] The small interfering RNA sequence is shown in SEQ ID NO:1 (5′CUGAUAAAGAGUUAUGCCATT-3′), and the antisense nucleotide sequence of the siRNA is shown in SEQ ID NO:2 (5′-UGGCAUAACUCUUUAUCAGTT-3′).

[0065] Figure 10 This is a representative image of Col I, αSMA Western blotting. Figure 10 A) and the results of quantitative and statistical analysis of protein content ( Figure 10 B).

[0066] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. The application of SUCNR1 gene expression inhibitors in the preparation of drugs to improve heart failure, characterized in that, The SUCNR1 gene expression inhibitor is a SUCNR1 gene knockout reagent; the SUCNR1 gene knockout reagent is siRNA, the siRNA sequence is shown in SEQ ID NO:1, and the antisense nucleotide sequence of the siRNA is shown in SEQ ID NO:

2. Small interfering RNA knockdown reduces the SUCNR1 protein level in cardiomyocytes or heart tissue.

2. The use of the SUCNR1 gene expression inhibitor as described in claim 1 in the preparation of a drug for improving heart failure, characterized in that, SUCNR1 gene expression inhibitors can suppress the increase in SUCNR1 protein levels in heart failure or fibrotic heart tissue in mice.

3. The use of the SUCNR1 gene expression inhibitor as described in claim 1 in the preparation of a drug for improving heart failure, characterized in that, SUCNR1 gene expression inhibitors can suppress the increase in mRNA expression levels of heart failure markers in the heart tissue of mice with heart failure, wherein the heart failure markers are ANP, BNP, β-MHC, Ctag, or Acta1.

4. The use of the SUCNR1 gene expression inhibitor as described in claim 1 in the preparation of a drug for improving heart failure, characterized in that, SUCNR1 gene expression inhibitors can suppress the decrease in the expression of mitochondrial functional markers in mouse fibrotic heart tissue. These mitochondrial functional markers are Nudfa11, SDHC, Uqcrb, Cox6a2, or ATP5e.

5. The use of the SUCNR1 gene expression inhibitor as described in claim 1 in the preparation of a drug for improving heart failure, characterized in that, SUCNR1 gene expression inhibitors can inhibit the destruction of mitochondrial morphology and dysfunction in fibrotic heart tissue of mice; SUCNR1 gene expression inhibitors can inhibit the damage to mitochondrial function in mouse cardiomyocytes, thereby inhibiting the decrease in oxygen consumption for ATP production and basal respiratory oxygen consumption.

6. The use of the SUCNR1 gene expression inhibitor as described in claim 1 in the preparation of a drug for improving heart failure, characterized in that, SUCNR1 gene expression inhibitors can suppress the increase in protein levels of myofibroblast markers Col I and αSMA, thereby inhibiting fibroblast transdifferentiation.

7. The use of the SUCNR1 gene expression inhibitor as described in claim 1 in the preparation of a drug for improving heart failure, characterized in that, SUCNR1 gene expression inhibitors can reduce the mRNA expression levels of heart failure biomarkers ANP, BNP, β-MHC, Ctag, and Acta1; SUCNR1 gene expression inhibitors can promote the increase in the expression levels of mitochondrial functional biomarkers, namely Nudfa11, SDHC, Uqcrb, Cox6a2, or ATP5e.

8. The use of the SUCNR1 gene expression inhibitor as described in claim 1 in the preparation of a drug for improving heart failure, characterized in that, SUCNR1 gene expression inhibitors, by knocking down SUCNR1, inhibit the transformation of fibroblasts into myofibroblasts and suppress the myofibroblast marker Col I, while increasing the protein expression level of fibronectin.

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