血管内皮细胞衰老相关circRNAs的功能和机制研究

Endothelial cell senescence can cause vascular dysfunction and promotes the occurrence and development of atherosclerosis. However the role of circRNA on endothelial cell senescence is still unknown. Our preliminary studies have revealed multiple Endothelial Cell Senescence associated-circRNAs (ECS-circRNAs) that are differentially expressed in senescent, as compared to young, endothelial cells using circRNA sequencing and qPCR validation. Our further investigation demonstrated that some of these ECS-circRNAs, including circPVT1 and circGNAQ, could regulate senescence in vascular endothelial cells. To confirm and expand our exciting results of circPVT1 and circGNAQ, here we propose: 1) to elucidate their functional roles on endothelial cell senescence through over-expression or inhibition of these two ECS-circRNAs in young/senescent endothelial cells; 2) to identify and characterize specific binding proteins of these two ECS-circRNAs by RNA pull-down and RIP, and investigate the underlying mechanism by which these circRNAs regulate endothelial cell senescence together with their binding proteins; 3) to study the association between these two ECS-circRNAs and vascular aging/atherosclerosis for their biological relevance, and their effect on vascular aging/atherosclerosis at ApoE-/- and WT mice. This study is expected to yield significant new insights into the biological function and molecular mechanisms of circPVT1 and circGNAQ in regulating endothelial cell senescence, and their causal contributions to vascular aging and cardiovascular diseases.

血管内皮细胞衰老可引起血管功能紊乱，促进动脉粥样硬化的发生发展。然而环状RNA（circRNA）在血管内皮细胞衰老中的作用机制尚未见报道。本项目前期研究发现，在年轻和衰老的血管内皮细胞中circRNA的表达谱差异明显，circPVT1和circGNAQ等差异表达明显的circRNAs可显著影响血管内皮细胞衰老。基于此，本项目拟以circPVT1和circGNAQ为研究重点，通过在血管内皮细胞中改变它们的表达，探讨circPVT1和circGNAQ对血管内皮细胞衰老相关表型的影响；鉴定circPVT1和circGNAQ的结合蛋白，探讨它们通过结合蛋白影响血管内皮细胞衰老的潜在机制；最后在动物水平上深入探讨它们对血管衰老和动脉粥样硬化发生发展的影响。本研究对于揭示circPVT1和circGNAQ调控血管内皮细胞衰老的作用机制，深化认识血管衰老和血管疾病的分子机制具有重要意义。

血管内皮细胞衰老可引起血管功能紊乱，促进动脉粥样硬化的发生发展。环状RNA（circRNA）是一类具有共价闭合环状结构的内源性RNA分子，参与细胞增殖、分化、凋亡等多种生物学过程。然而circRNA在血管内皮细胞衰老中的作用机制尚待挖掘。本项目前期研究发现，在年轻和衰老的血管内皮细胞中circRNA的表达谱差异明显，ciPVT1和circGNAQ等差异表达的circRNAs可能与血管内皮细胞衰老密切相关。本项目以ciPVT1和circGNAQ等环状RNAs为研究重点，通过在血管内皮细胞中改变它们的表达，探讨这些环状RNAs对血管内皮细胞衰老的影响；鉴定与这些环状RNAs结合的蛋白或miRNA，探讨它们影响血管内皮细胞衰老的潜在机制；最后在动物水平上深入探讨它们对血管衰老和动脉粥样硬化发生发展的影响。本项目的研究结果发现，ciPVT1、circGNAQ在年轻血管内皮细胞中高表达，而circFOXO3在衰老血管内皮细胞中显著上调，提示ciPVT1、circGNAQ和circFOXO3与血管内皮细胞衰老密切相关。体外研究结果发现，改变ciPVT1、circGNAQ和circFOXO3的表达均可显著影响血管内皮细胞衰老。进一步机制研究发现，位于PVT1内含子区的环状RNA ciPVT1可通过吸附miR-24-3p抑制CDK4的表达，导致Rb磷酸化被抑制，进而延缓血管内皮细胞衰老；在血管内皮特异性高表达的环状RNA circGNAQ，可作为内源性miR-146a-5p海绵，通过吸附miR-146a-5p促进其靶基因PLK2的表达，从而延缓血管内皮细胞衰老和动脉粥样硬化形成。本项目的研究成果对于理解环状RNA影响血管内皮细胞衰老的作用机制，深化认识血管衰老和动脉粥样硬化的分子机制具有重要的意义，并为延缓血管衰老、预防和治疗动脉粥样硬化性心血管疾病提供新的治疗靶点和应对策略。