HMGB1通过调控细胞焦亡与自噬参与冠状动脉微栓塞致心肌损伤的机制研究

Coronary microembolization (CME) is an intractable complication of acute coronary syndrome and percutaneous coronary intervention. It is believed to be the first cause of no-reflow, while the underlying mechanisms of CME-induced myocardial damage remain unclear. Our pre-experiment showed that myocardial pyroptosis was markedly upregulated and autophagy was downregulated, meanwhile, the expression level of HMGB1, an activator of TLR4 inflammatory signaling pathway was increased in rat hearts with CME. The results in vitro oxygen-glucose deprivation (OGD) model of human induced pluripotent stem cells-derived cardiomyocytes (hiPSCs-CMs) were consistent with these. Thus, we hypothesized that HMGB1/TLR4 signaling pathway was involved in CME-induced myocardial damage by regulating pyroptosis and autophagy. Here we will establish rat CME models and in vitro OGD cardiomyocytes model, then manipulate the expression of HMGB1 and TLR4 using gene transfection techniques both in vivo and in vitro, to analyze the consequences on myocardial pyroptosis, autophagy and their effect on myocardial damage and cardiac function. Moreover, other molecular biological techniques will also be employed including quantification of calcium transient amplitude and autophagic flux assays to clarify the possible underlying molecular mechanisms. This work will be greatly helpful to elucidate the specific role of HMGB1/TLR4 signaling pathway in myocardial damage following CME and provide new insight into the prevention and treatment against CME for patients with coronary heart disease.

冠状动脉微栓塞（CME）是急性冠脉综合征及其介入治疗的严重并发症，同时也是冠脉无复流的首要原因，但其致心肌损伤的具体分子机制目前仍不清楚。我们前期研究发现大鼠CME模型及人源多能诱导干细胞分化的心肌细胞（hiPSCs-CMs）缺氧-缺糖模型（OGD）中心肌焦亡途径激活，自噬被抑制，同时TLR4炎性信号通路激活因子HMGB1表达明显增加。由此我们提出假说：CME后HMGB1通过TLR4相关通路调控心肌焦亡与自噬参与CME致心肌损伤的发生与发展。本研究拟构建大鼠CME模型及hiPSCs-CMs的OGD模型，应用rAAV9体内转染基因干扰技术、心肌细胞钙瞬变检测、自噬流动态监测、透射电镜及其他分子生物学技术，从体内与体外两方面探讨HMGB1在CME致心肌损伤中的作用，为冠心病患者并发CME后心肌损伤的防治提供新的研究思路和精准医学干预靶点。

冠状动脉微栓塞（CME）被认为是无复流的首要原因，其致心肌损伤的具体分子机制目前仍不清楚。前期研究发现大鼠CME模型及人源多能诱导干细胞分化的心肌细胞 （hiPSCs-CMs）缺氧-缺糖模型（OGD）中心肌焦亡途径激活，自噬水平显著抑制，同时HMGB1 基因表达水平显著增加。HMGB1 可与其受体TLR4结合，激活下游NLRP3/Caspase-1 信号通路。我们提出假说：CME后HMGB1通过TLR4/NLRP3/Caspase-1 信号通路调控心肌焦亡与自噬参与CME致心肌损伤及心功能障碍的发生与发展。本研究通过构建大鼠CME动物模型，同时应用hiPSCs分化的心肌细胞构建OGD 体外细胞模型，从体内与体外两方面明确了HMGB1及其调控的焦亡与自噬在 CME 致心肌损伤中的作用及调控机制，同时证实 HMGB1 作用于TLR4/NLRP3/Caspase-1信号通路发挥调控心肌焦亡与自噬的作用，并最终明确 HMGB1/TLR4/NLRP3/Caspase-1信号通路的激活介导心肌损伤的病理生理机制，预期研究目标均已完成。该研究结果对未来冠心病患者人群冠脉微循环障碍的防治药物研发提供全新靶点，有望从基因层面精准调控心肌细胞的程序性死亡进程，包括心肌细胞焦亡及自噬，并最终降低冠心病患者人群心功能的恶化进展。