Ripk3/Parkin/线粒体自噬/mPTP开放介导的坏死性凋亡在心梗后心室重构中的作用和机制研究

Previous studies have shown that Ripk3 promotes myocardial death by activating necroptosis. However，the downstream molecular mechanisms of Ripk3 affecting myocardial activity and function in ventricular remodeling after myocardial infarction remain unclear. Our previous findings suggest that mPTP opening is a key point in Ripk3-induced necroptosis in myocardial ischemia-reperfusion injury models. But, the underlying mechanism by which Ripk3 promotes mPTP opening in ventricular remodeling after myocardial infarction has not been reported. In response to mitochondrial injury, Parkin-mediated mitophagy can counter excessive mPTP opening. Our previous work also found that Ripk3 can weaken the protective effects of mitophagy, thus amplifying mitochondrial damage in ischemia-reperfusion injury. It remains unclear whether Ripk3 can promote mPTP opening by inhibiting Parkin-mediated mitophagy in ventricular remodeling after myocardial infarction. Therefore, we hope to clarify the regulatory mechanism of Ripk3 induced necroptosis with inhibiting parkin-mediated mitophagy which promoting mPTP opening in ventricular remodeling after myocardial infarction through knockout mice and knockdown and overexpress target proteins. These studies provide new theoretical hypotheses and clinical intervention molecular targets for the pathological mechanism of myocardial remodeling after myocardial infarction.

Ripk3通过激活坏死性凋亡促进心肌的死亡。但目前仍不清楚在心梗后心室重构中，Ripk3通过何种下游机制影响心肌活性和功能。本团队前期在再灌注损伤模型中发现，mPTP开放是Ripk3诱发心肌坏死性凋亡的关键，但心梗后心室重构中Ripk3如何影响mPTP开放还未见报道。针对线粒体损伤，线粒体自身可通过激活Parkin/线粒体自噬来对抗过度的mPTP开放。课题组还发现Ripk3会干扰线粒体自噬的保护作用，从而扩大再灌注条件下的线粒体损伤。现阶段仍不清楚，在心梗后心室重构中Ripk3能否通过压制Parkin/线粒体自噬从而促进mPTP开放。由此，本项目通过基因敲除小鼠等技术，希望阐明心梗后心室重构中心肌坏死性凋亡的调节机制，明确Parkin/线粒体自噬受到Ripk3的负性调控，从而促进mPTP开放，最终激活心肌坏死性凋亡的机制。上述研究将为心梗后心室重构的干预提供新的靶点。

心梗后的心室重构是导致慢性心力衰竭发展的重要因素，其中心肌细胞死亡是导致心室重构的关键。在心梗后心室重构中，Ripk3介导的心肌细胞necroptosis约占死亡心肌细胞数目的50-60%。但目前仍不清楚在心梗后心室重构中，Ripk3通过何种下游机制影响心肌活性和功能。本项目提出：在心梗后心室重构中，Ripk3通过调控Parkin，抑制线粒体自噬，导致大量损伤的线粒体在细胞内聚集，破坏了线粒体的结构和功能稳态，导致mPTP开放，最终诱导心肌细胞发生necroptosis。本项目执行期间，我们发现：在心梗后心室重构中，Ripk3的表达显著升高；通过构建Ripk3基因敲除小鼠，我们发现在心梗后心室重构中，基因敲除Ripk3可以显著减轻心肌细胞necroptosis，减轻心肌损伤，保护心功能。机制上，表达上调的Ripk3通过抑制AMPK信号通路，进而抑制Parkin介导的线粒体自噬，导致mPTP开放增加，最终激活心肌细胞necroptosis。本研究为心梗后心室重构的干预提供潜在的治疗靶点。