基于组蛋白去乙酰化酶调控心肌损伤修复中树突细胞与成纤维细胞交互作用机制的研究

Repair of necrotic myocardium is a key factor that affecting prognosis in patients with acute myocardial infarction. Our research had verified that differentiation of dendritic cells (DCs), a cell belong to innate immune system, increases in infarcted myocardium and that trichostatin A (TSA), the inhibitor of the histone deacetylases (HDACs), decreases the size of infarcted myocardium. These results suggest that HDACs participated in the regulation of cardiac repair after acute myocardial infarction. STAT5 is the main transcriptional factor that regulating differentiation of DCs in heart. However, there is no reports about HDACs controlling cardiac repair of necrotic myocardium through STAT5 acetylation. On account of the hypothesis that HDACs controlling STAT5 acetylation, this project plan to clarify the effects of direct and indirect interaction of DCs and fibroblast on cardiac function and activation of fibroblast in animal model and cells co-culture system. So, the dynamics of interaction between DCs and fibroblast and its relationship with cardiac repair will be identified. HDACs inhibitor and siRNA technique will be utilized to discover the specific type(s) of HDACs involved in STAT5 acetylation. The mechanism of HDACs acetylation regulation in cardiac repair will be revealed. These results will provide new strategy for treatment of myocardial infarction.

心肌梗死后坏死心肌的修复程度是影响心梗病人预后的主要因素，本项目前期工作已证实，固有免疫系统的树突细胞（DCs）在梗死后心肌组织分化增多，组蛋白去乙酰化酶（HDACs）抑制剂曲古菌素A缩小急性心肌梗死大鼠梗死面积，提示HDACs参与此过程的调控；STAT5是心脏调节DCs分化成熟的主要转录因子，但目前关于HDACs参与STAT5乙酰化调控心脏的损伤修复尚未见相关报道。本项目基于HDACs调控STAT5乙酰化为切入点，采用动物模型及细胞共培养体系，揭示DCs与成纤维细胞直接与间接交互作用对心肌细胞功能评价和成纤维细胞活化的影响，明确心梗损伤修复中DCs与成纤维细胞交互作用的动态规律及其与损伤修复的关系；采用选择性HDACs抑制剂、siRNA等技术，探讨基于何种HDACs参与介导STAT5的乙酰化调控，阐明HDACs参与的乙酰化修饰调控心肌损伤修复的机制，为心肌梗死治疗提供新策略。

固有免疫系统的DCs在心梗后的心肌组织损伤修复中发挥重要作用。本项目假设组蛋白去乙酰化酶（HDACs）通过乙酰化修饰及转录机制调控心肌组织DCs数量、定位、成熟及功能等，而影响心肌的损伤修复过程。为验证这一假设，实验采用急性心肌梗死大鼠模型，给予HDACs抑制剂，确定HDACs对心肌梗死面积、损伤与修复指标等的影响，证实HDACs参与心肌梗死发生发展过程；确定在梗死后1、3、7、14和28天DCs定位和数量的动态变化，阐明HDACs基于STAT5等转录因子参与心肌组织中DCs成熟和损伤修复的调控机制。通过在体实验证实，HDACs基于MG53和ORAII影响细胞内Ca2+水平，调控CRT在细胞表面富集，影响DCs成熟。HDACs抑制剂TSA通过改变FoxO3a基因启动子区组蛋白H4的乙酰化水平影响其表达，干预心肌炎症性凋亡。采用生物信息学分析方法，筛选并验证急性心肌梗死患者外周血芯片表达谱的差异表达基因等发现，TBX21和PRF1可能为急性心肌梗死的潜在调控靶点。以DC2.4细胞为研究对象发现，TSA诱导其共刺激分子CD80和CD86表达，降低FITC-葡聚糖摄取，促进DC2.4迁移。TSA减少细胞因子IL-1β、IL-10、IL-12和TGF-β分泌，增强HIF-1α依赖的糖酵解基因表达，通过上调SRSF3增加了PKM2表达，提示OGD条件下TSA通过调节依赖于SRSF3-PKM2糖酵解途径影响DC2.4功能。采用BMDCs-NIH3T3细胞共培养体系发现，HDACs基于Ca2+介导ERS，调节OGD条件下BMDCs-NIH3T3共培养体系的胶原分泌，揭示DCs与成纤维细胞相互作用对心梗损伤修复的影响及乙酰化调控机制，为心肌梗死治疗提供新策略。