FUNDC1下调减少线粒体自噬促发衰老血管内皮功能障碍

FUNDC1 down-regulation reduces mitophagy and contributes to aging vascular endothelial dysfunction

目的探讨FUNDC1介导的线粒体自噬在冠脉血管老化中的作用。方法利用18月龄的老龄小鼠和8周龄的年轻对照小鼠,探究年龄与冠状动脉内皮功能的关系。分离培养小鼠心肌组织原代微血管内皮细胞(CMECs),传代40次构建衰老模型,使用mt-Keima 543/458 nm荧光检测线粒体自噬,MitoSOX和JC-1检测线粒体ROS水平和膜电位。构建FUNDC1内皮特异性敲除(Fundc1fl/Y/Tek-Cre)小鼠,并采用腺相关病毒进行内皮特异性过表达FUNDC1,验证FUNDC1在衰老导致内皮功能障碍中的关键作用。结果老龄小鼠冠状动脉呈现舒张功能障碍、内皮细胞FUNDC1表达降低(P<0.01)。衰老导致CMECs线粒体自噬受损,线粒体膜电位异常和ROS堆积。内皮特异性FUNDC1缺失导致小鼠冠状动脉功能下降,衰老相关β-半乳糖苷酶(SA-β-gal)阳性染色增加。FUNDC1过表达可改善衰老引起的冠状动脉内皮功能下降并减少SA-β-gal阳性染色。结论FUNDC1下调及其诱导的线粒体自噬降低是衰老冠脉内皮功能障碍的重要原因之一,本研究可为缓解血管内皮衰老提供新的思路和靶点。

AIM To investigate the role of FUNDC1-mediated mitophagy in coronary vascular aging.METHODS Aged mice(18 months)and young mice(8 weeks)were used to explore the relationship between age and coronary endothelial function.Primary cardiac microvascular endothelial cells(CMECs)from mouse myocardial tissue were isolated and cultured,and the aging model was constructed by 40 passages.Mitophagy levels in CMECs were measured using mt-Keima 543/458 nm fluorescence,and mitochondrial ROS levels and membrane potential were measured using MitoSOX and JC-1.Endothelialspecific FUNDC1 knockout(Fundc1fl/Y/Tek-Cre)mice were constructed and endothelial-specific over-expression of FUNDC1 was performed using adeno-associated virus to verify the key role of FUNDC1 in endothelial dysfunction caused by aging.RESULTS The coronary arteries of aged mice showed diastolic dysfunction and decreased FUNDC1 expression in endothelial cells(P<0.01).Aging led to impaired mitophagy,abnormal mitochondrial membrane potential and ROS accumulation in CMECs.Deletion of endothelium-specific FUNDC1 resulted in decreased coronary artery function and increased senescence-associatedβ-galactosidase(SA-β-gal)positive staining in mice.FUNDC1 over-expression improved aging-induced coronary endothelial function and reduced SA-β-gal positive staining.CONCLUSION Down-regulation of FUNDC1-mediated mitochondrial autophagy is one of the important causes of aging coronary endothelial dysfunction,and this study provides new ideas and targets for alleviating vascular endothelial aging.