The Mechanism Of Trichostatin A Based On The Intercellular Ca²⁺ Induced CRT Influencing Dendritic Cells Matured In Myocardial Infarction Tissue Of Rat

MI?Myocardial Infarction?,which is induced by persistent ischemia and hypoxia in coronary.It induces myocardial tissue necrosis,and is always suffered suddenly,which leads to ventricular remodeling,even heart failure.At the same time,Ca²⁺homeostasis plays an important role in maintaining cell physiological function.Thus,Ca²⁺has an intimate relationship with MI.Besides,ORAI1 located on cell membrane is an effective target to regulate the level of cytoplasm Ca²⁺.The change of intracellular Ca²⁺makes cardiomyocytes release DAMPs,including CRT,HMGB1and HSPs,etc.CRT protein located on cell membrane,is the signal of“eat me”for mature DCs.However,the expression of CRT protein on cell membrane also can induce multiple immune reaction,and as to this,the endoplasmic reticulum stress is a necessary process.Therefore,the regulation of Ca²⁺level after MI plays an important role in saving MI patients clinically.Our previous study had found that TSA could increase the number of matured DCs in the rat heart after MI.And the results indicated that TSA could regulate the expression of MG53.MG53,a specific protein expresses in cardiomyocytes and skeletal muscle.According to the reported study,MG53 could interact with ORAI1,and then influenced the Ca²⁺influx,Thus,the regulation of MG53 make an important effort on curing heart disease.In summary,we hypothesis that TSA could influence Ca²⁺homeostasis to induce CRT to express on cardiomyocytes membrane,and then promote the maturation of DCs.At the end,aiming to improve myocardial tissue injury,and protect the infarcted heart.Objectives:The aim of this study is to investigate TSA could influence Ca²⁺influx to induce CRT to express on cardiomyocytes membrane,and then promote the maturation of DCs.And,aiming to promote to active the DCs after the MI,at the same time,improve myocardial tissue injury and protect the infarcted heart.Methods:In this study,male Wistar rats were used in the research.The model of myocardial infarction was established by the left anterior descending coronary artery ligation.To observe the protective effects of TSA on infarction myocardium.TTC staining was used to detect the area of myocardial infarction,and HE staining was used to observe the tissue injury.Western Blot was used to measure the expression of MG53,ORAI1,GRP78 and XBP1,etc.In the infarcted myocardial tissue,flow cytometry was used to measure the number of matured DCs,the level of the expression CRT protein on cardiomyocytes membrane and the level of Ca²⁺in the cytoplasm.Results:Compared with the control group,myocardial infarct size increased at 1,7 and14 days after myocardial infarction?P<0.05?,the tissues of Model group were more irregular and had more edema,and there are more inflammatory cells in the infarct area;Compared with the Model group,the infarct sizes were greatly reduced by TSA treatment?P<0.05?,and the tissue in Model-TSA group improved a lot.At 7 days after myocardial infarction,compared with the control group,the number of the CD103⁺/CD80⁺cells increased?P<0.05?;and compared with the Model group,the number of the CD103⁺/CD80⁺cells also increased?P<0.05?.However,compared with the control group,the expression of the MG53 protein in CD103⁺/CD80⁺cells increased;and compared with the Model group,the expression of the MG53 protein in CD103⁺/CD80⁺cells also increased?P<0.05?.At 1 day,7 days and 14 days after myocardial infarction,compared with the control group.At 1 day and 7 days,the expression of myocardial GRP78 and SERCA2a protein were upregulated?P<0.05?;at 7 day and 14 days,and the expression of myocardial GRP78 and SERCA 2a protein were also upregulated?P<0.05?in the Model-TSA group as to the Model group.The expression of myocardial Caspase 12protein was upregulated in the Model group compared with control?P<0.05?;but at 7day and 14 days,the Model-TSA group expression of myocardial Caspase 12 protein was downregulated?P<0.05?.Because of the obvious change in the 7 days,we evaluated at 7 days after MI the expression of the total CRT protein and the CRT on the cardiomyocytes membrane.The results were the total CRT protein increased in the Model group?P<0.05?;but compared with Model group,total CRT protein decreased in the Model-TSA group?P<0.05?.However,the CRT protein on the cardiomyocytes membrane increased in the Model group?P<0.01?;and compared with Model group,the CRT protein on the cardiomyocytes membrane increased in the Model-TSA group?P<0.01?.At 1 day,7 days and 14 days after myocardial infarction,compared with the control group,MG53 and ORAI1 protein increased?P<0.05?in the Model group.At1 day and 7 days,compared with the Model group,the expression of myocardial MG53 and ORAI1 protein were greatly increased by TSA treatment?P<0.05?.Because of the obvious change in the 7 days,we evaluated at 7 days after MI the expression of the intercellular Ca²⁺,TSA also increased intercellular Ca²⁺as to Model group?P<0.05?.We administrated Verapamil to the rats,and at 7 days after MI,the results were showed below.Verapamil could decreese the level of Ca²⁺in Model-TSA group?P<0.05?,and the expression of Caspase 12?XBP1 and GRP78 protein also decreased?P<0.05?.Besides,total CRT protein was increased by Verapamil?P<0.05?,but CRT protein on the surface of cell was decreased by Verapamil.And the number of the CD103⁺/CD86⁺cells decreased in the Model-Verapamil group?P<0.05?;Compared with the Model group,the expression of myocardial MG53 and ORAI1protein were increased by Verapamil treatment?P<0.05?.Conclusions:?1?TSA could regulate the expression of CRT protein on cardiomyocytes membrane to induce the maturation of DCs.?2?TSA could regulate the level of Ca²⁺in the cytoplasm to increase the expression of CRT protein on cardiomyocytes membrane.?3?TSA might upregulate the level of MG53 and ORAI1 protein,and then upregulate the level of Ca²⁺in the cytoplasm.