Table_7_MEF2A Is the Trigger of Resveratrol Exerting Protection on Vascular Endothelial Cell.DOCX

Both resveratrol and myocyte enhancer factor 2A (MEF2A) may protect vascular endothelial cell (VEC) through activating the expression of SIRT1. However, the relationship between resveratrol and MEF2A is unclear. We aimed to investigate the deeper mechanism of resveratrol in protecting vascular endothelial cells and whether MEF2A plays a key role in the protective function of resveratrol. Human umbilical vein endothelial cell (HUVEC) was used for in vitro study, and small interfere RNA was used for silencing MEF2A. Silencing MEF2A in the vascular endothelium (VE) of ApoE−/− mice was performed by tail injection with adeno associated virus expressing si-mef2a-shRNA. The results showed that treatment of HUVEC with resveratrol significantly up-regulated MEF2A, and prevented H2O2-induced but not siRNA-induced down-regulation of MEF2A. Under various experimental conditions, the expression of SIRT1 changed with the level of MEF2A. Resveratrol could rescue from cell apoptosis, reduction of cell proliferation and viability induced by H2O2, but could not prevent against that caused by silencing MEF2A with siRNA. Silencing MEF2A in VE of apoE−/− mice decreased the expression of SIRT1, increased the plasma LDL-c, and abrogated the function of resveratrol on reducing triglyceride. Impaired integrity of VE and aggravated atherosclerotic lesion were observed in MEF2A silenced mice through immunofluorescence and oil red O staining, respectively. In conclusion, resveratrol enhances MEF2A expression, and the upregulation of MEF2A is required for the endothelial protective benefits of resveratrol in vitro via activating SIRT1. Our work has also explored the in vivo relevance of this signaling pathway in experimental models of atherosclerosis and lipid dysregulation, setting the stage for more comprehensive phenotyping in vivo and further defining the molecular mechanisms.

白藜芦醇及心肌增强因子2A（MEF2A）均可能通过激活SIRT1的表达来保护血管内皮细胞（VEC）。然而，白藜芦醇与MEF2A之间的关系尚不明确。本研究旨在深入探究白藜芦醇在保护血管内皮细胞中的机制，以及MEF2A是否在白藜芦醇的防护功能中发挥关键作用。本研究采用人脐静脉内皮细胞（HUVEC）进行体外实验，并使用小干扰RNA沉默MEF2A。通过尾静脉注射表达si-mef2a-shRNA的腺相关病毒，在ApoE−/−小鼠的血管内皮（VE）中沉默MEF2A。结果显示，白藜芦醇处理HUVEC显著上调MEF2A的表达，并防止了H2O2诱导的MEF2A下调，而非siRNA诱导的下调。在多种实验条件下，SIRT1的表达随MEF2A水平的变化而变化。白藜芦醇可以挽救由H2O2诱导的细胞凋亡、细胞增殖减少和活力降低，但不能防止由siRNA沉默MEF2A引起的上述现象。在apoE−/−小鼠的VE中沉默MEF2A会降低SIRT1的表达，增加血浆LDL-c水平，并消除白藜芦醇降低甘油三酯的功能。通过免疫荧光和油红O染色观察到，在MEF2A沉默的小鼠中，血管内皮的完整性受损，动脉粥样硬化病变加重。总之，白藜芦醇可增强MEF2A的表达，且MEF2A的上调对于白藜芦醇在体外通过激活SIRT1发挥内皮保护作用是必需的。本研究还探讨了这一信号通路在动脉粥样硬化和脂质代谢紊乱的实验模型中的体内相关性，为体内更全面的表型分析和进一步阐明分子机制奠定了基础。