(BioRxiv All) M6A-modified circEZH2 Protects Endothelial Cells from Senescence and Suppresses Atherosclerosis by Stabilizing ZNF326: Objective: Endothelial cell senescence induces endothelial dysfunction, thereby contributing to atherosclerosis progression. Circular RNAs… #BioRxiv #MassSpecRSS
Objective: Endothelial cell senescence induces endothelial dysfunction, thereby contributing to atherosclerosis progression. Circular RNAs (circRNAs) play diverse roles in multiple physiological and pathological processes. N6-methyladenosine (m6A) is the most abundant internal RNA modification in eukaryotic RNAs and dynamically regulates RNA fate and function. However, the functions and therapeutic potential of m6A-modified circRNAs in endothelial cell senescence remain unknown. Approach and Results: m6A-modified circRNAs associated with endothelial cell senescence were screened by circRNA expression and m6A-circRNA microarray profiling of endothelial cells and mouse aortic intima. circEZH2 expression was validated in endothelial cells, vascular tissues, and human atherosclerotic plaques by RT-qPCR, and RNA fluorescence in situ hybridization. The role of circEZH2 in endothelial senescence and atherosclerosis was assessed in vitro and in vivo. RNA pull-down, mass spectrometry, RNA immunoprecipitation, co-immunoprecipitation, ubiquitination assays, and rescue experiments were used to define the underlying mechanism. We identified A novel m6A-modified circRNA, circEZH2, that was downregulated in the aged aortic intima and advanced plaques. CircEZH2 was stabilized by m6A reader IGF2BP2. Endothelial cell-specific overexpression of circEZH2 delayed senescence and suppressed atherosclerosis progression. At the cellular level, circEZH2 overexpression delayed senescence, decreased p53/p21 levels and increased angiogenic activity of endothelial cells, while circEZH2 knockdown exhibited the opposite effect. Mechanistically, circEZH2 functions as a scaffold to promote USP37-mediated deubiquitination, thereby stabilizing ZNF326. Moreover, endothelial cell-specific knockdown of ZNF326 counteracts the anti-senescent and anti-atherosclerotic effects mediated by circEZH2 overexpression. Conclusion: In summary, the present study identifies circEZH2 as a novel suppressor of endothelial cell senescence, highlighting its potential as a therapeutic target for age-related atherosclerosis.
