| Cardiac repair is essential to restore the integrity and function of the heart after myocardial infarction(MI).Necrosis of cardiomyocytes stimulate fibroblast proliferation and transformation,and promote collagen expression.Increased collagen can fill the necrotic myocardial tissue,but excessive collagen deposition can cause cardiac dysfunction and lead to heart failure.Therefore,finding a strategy to effectively regulate the expression of collagen-mediated tissue repair after MI is of great significance for maintaining cardiac function and the prognosis of MI.Myocardial fibroblasts,as the main cell component of myocardial tissue,are the main source of extracellular matrix such as collagen during normal and infarction heart.The collagen expression of fibroblasts is regulated by inflammation and other factors.In recent years,literature reports and previous work of our lab have found that the number of dendritic cells(DCs)has increased in the myocardial infarction area and the border of myocardial infarction area,and DCs are involved in the inflammatory response after MI.At present,the mechanism of DCs regulating fibroblasts participating in the repair of myocardial tissue has not yet been elucidated after MI.Trichostatin A(TSA)is a histone deacetylase inhibitor.At present,similar drugs have been used in clinical tumor treatment.Our previous research found that TSA can reduce the area of myocardial infarction and reduce the damage of myocardial tissue in rats with MI.In summary,we speculate that TSA may regulate the number and function of DCs,mediate the collagen expression in fibroblasts,and participate in tissue repair after MI.Objectives:Rat MI model and the oxygen-glucose deprivation model were used to investigate whether TSA affects the expression of collagen in fibroblast by regulating the number and function of DCs after MI;clarify the regulatory mechanism of TSA involved in tissue repair after MI,and provide a new strategy for the clinical treatment of MI.Methods:Rat MI model was established by ligating the left anterior descending coronary artery.After administration of TSA,echocardiography was used to detect cardiac function in rats.Immunohistochemical and Western Blot methods were used to detect the expression of collagen in rat myocardial tissue.Flow cytometry was used to detect the number of CD103~+/CD86~+DCs in rat myocardial tissue.Cytokine chip was used to detect the cytokine content of rat myocardial tissue.This experiment is based on the oxygen-glucose deprivation model to simulate the hypoxia and hypoglycemia conditions after MI.The supernatant of TSA pretreated DCs was administered to NIH3T3 fibroblasts.The collagen expression of NIH3T3fibroblasts was detected by Western Blot method.Proteomics was used to detect the protein expression level under different conditions and screen differentially expressed proteins of NIH3T3 fibroblasts.Western Blot and ELISA methods were used to detect the expression level of fatty acid metabolism pathway proteins and the content of enzymes in NIH3T3 fibroblasts.After Etomoxir interfered with the fatty acid metabolism of NIH3T3 fibroblasts,the expression of collagen in NIH3T3 fibroblast was detected by Western Blot method.After mycophenolate mofetil interfered with the secretion of DCs cytokine,the expression of collagen in NIH3T3 fibroblast was detected by Western Blot method.Results:1.The effect of TSA on the expression of collagen in myocardial tissue of rats with MITSA significantly increased the ejection fraction and shortening fraction of the heart,improved heart function;and reduced the expression of Collagen I,Collagen III,?-SMA and TGF-?1 proteins in myocardial tissue of rats with MI.2.TSA regulates the effect of DCs on fibroblasts under oxygen-glucose deprivation conditionsTSA increased the number of CD103~+/CD86~+DCs in myocardial tissue of rats with MI,and reduced the content of cytokines(IL-1?,IL-1?,IL-13 and IFN-?)in myocardial tissue.TSA pretreatment of DCs supernatant significantly reduced the expression of collagen in NIH3T3 fibroblasts under oxygen-glucose deprivation conditions.3.TSA regulates DCs-mediated fatty acid metabolism and affects the expression of collagen in fibroblastsProteomics results showed that there were 468 differentially expressed proteins in NIH3T3 fibroblasts under oxygen-glucose deprivation conditions,which upregulated the proteins expression of medium-chain specific acyl-Co A dehydrogenase(ACADM),short-chain specific acyl-Co A dehydrogenase(ACADS),hydroxyacyl-coenzyme A dehydrogenase(HADH)and trifunctional enzyme subunit beta(HADHB);60 differentially expressed proteins in NIH3T3 fibroblasts of TSA group under oxygen-glucose deprivation conditions;290 differentially expressed proteins in NIH3T3 fibroblasts in the TSA pretreatment of DCs group under oxygen-glucose deprivation conditions,which downregulated the proteins expression of acetyl-Co A carboxylase(ACACA)and fatty acid synthase(FASN);enrichment analysis of KEGG pathway showed that fatty acid metabolism pathway was the one of main pathways involved in the regulation of different groups of proteins.TSA pretreatment of DCs supernatant reduced the content of free fatty acids and triglycerides in NIH3T3 fibroblasts under oxygen-glucose deprivation conditions;decreased the proteins expression of ACADM,HADH,carnitine palmitoyltransferase1A(CPT1A),carnitine palmitoyltransferase 2(CPT2),ACACA and FASN,and reduced the contents of fatty acyl-coenzymes A and malonyl-coenzymes A in NIH3T3fibroblasts under oxygen-glucose deprivation conditions.The results of using Etomoxir to interfere with fatty acid metabolism pathway showed that after TSA regulated DCs to influence the fatty acid metabolism pathway of NIH3T3 fibroblasts,it inhibited the expression of Collagen I and Collagen III in NIH3T3 fibroblasts.Mycophenolate mofetil interferes with the secretion of DCs cytokines,and can inhibit the regulation of Collagen I and Collagen III of NIH3T3fibroblasts in the supernatant of DCs pretreated by TS A under oxygen-glucose deprivation conditions.Conclusions:1.TSA improves the cardiac function,and affects the tissue repair by changing the collagen expression in myocardial tissue of rats with MI.2.TSA regulates the cytokine secretion of DCs and inhibits the expression of collagen in NIH3T3 fibroblasts under oxygen-glucose deprivation conditions.3.Fatty acid metabolism pathway is one of the pathways that TSA regulates DCs to inhibit the expression of collagen in NIH3T3 fibroblasts under oxygen-glucose deprivation conditions. |
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