piRNA调控的线粒体分裂在血管平滑肌细胞凋亡中作用机理的研究

Mitochondrion plays an essential role in maintaining cardiovascular homeostasis.PiRNAs could have important role in the regulation of molecular events of mitochondrial dynamics as well as cardiovascular homeostasis. However, it is still remains unknown. This project intends to explore whether piRNA has influence in the regulation of vascular homeostasis by regulating the dynamics of mitochondrion. By deep sequencing analysis, we screened the potential piRNA associated with atherosclerosis and our further study found that knockdown of piRNA-16 promotes cell apoptosis and mitochondrial fission of vascular smooth muscle cells. Moreover, the cellular phenotype change can be recovered by over expression of mitochondrial fusion gene OPA1. This was the first stidy linking mammalian piRNA and mitochondrial morphology as well as it's function in atherosclerosis. This project will focus on the following questions: (1) whether there is a potential regulatory piRNA in atherosclerosis animal models? (2) whether piRNA-16 regulates vascular smooth muscle apoptosis and mitochondrial division? (3) whether piRNA regulates these process by regulating OPA1,a mitochondrial dynamic? By successful completion of this project, our study will provide a new basis for the impact of piRNA on the development of atherosclerosis. In addition, it could provide a new potential target for the prevention.and treatment of atherosclerosis.

线粒体在维持心血管系统稳态中起着十分重要的作用。piRNA可能在其中发挥重要的分子调控功能，但具体机制尚不清楚。本项目拟从piRNA调控线粒体动态结构入手，探究其在血管系统稳态调节中的潜在功能。我们通过深度测序筛选得到调控动脉粥样硬化的piRNA，进一步研究发现敲减心血管特异性表达的piR-16会促进血管平滑肌细胞凋亡和线粒体分裂，其相关表型可以被线粒体融合基因OPA1过表达恢复，上述发现首次将哺乳动物中piRNA与动脉粥样硬化及线粒体形态功能联系起来。本项目将主要研究以下问题：（1）动脉粥样硬化动物模型中是否存在发挥调控作用的潜在piRNA？（2）piR-16是否调节血管平滑肌凋亡和线粒体分裂？（3）piRNA是否通过调节OPA1调控线粒体分裂和血管平滑肌凋亡？通过以上研究将为piRNA对动脉粥样硬化发生发展的调控机制提供新的理论基础，为动脉粥样硬化的预防和治疗提供新的靶点。

线粒体在维持心血管系统稳态中起着十分重要的作用。piRNA是一类新发现的小分子非编码核酸，其可能在心血管疾病中发挥重要的分子调控功能，但具体机制尚不清楚。本项目从piRNA调控线粒体动态结构入手，探究其在血管系统稳态调节中的潜在功能。我们通过深度测序筛选得到调控动脉粥样硬化的piRNA，进一步研究发现敲减心血管特异性表达的piRNA-16会促进血管平滑肌细胞凋亡和线粒体分裂，其相关表型可以被线粒体融合基因OPA1过表达恢复，上述发现首次将哺乳动物中piRNA与动脉粥样硬化及线粒体形态功能联系起来。机制方面，首先我们通过生物信息学手段分析piRNA-16的种子序列主要和动脉粥样硬化敏感基因HNRNP-K结合，预示着HNRNP-K可能是它的主要下游靶标。经过WB和IF等手段检测证实piRNA-16过表达后HNRNP-K的蛋白表达水平被明显抑制，反之，敲低PiRNA-16后，HNRNP-K被明显上调。进一步研究发现，piRNA-16可以明显的抑制P21的表达。最后，我们通过构建APOE-/-动脉粥样硬化模型小鼠，尾静脉注射piRNA-16 argomir，发现过表达piRNA-16可以显著抑制动脉粥样硬化斑块的数量，并且减少了内膜和中膜的厚度等病理进程。通过此项研究为piRNA对动脉粥样硬化发生发展的调控机制提供了新的理论基础，为动脉粥样硬化疾病的预防、治疗提供了新的靶点。