1型多聚ADP核糖合成酶对动脉粥样硬化血管平滑肌功能的调控机制研究

Vascular smooth muscle cell (VSMC) dysfunction and phenotypic transition in response to proatherosclerotic stimuli promote vascular lipid uptake, inflammation and calcification, leading to vascular stiffness, stenosis, thrombosis，and plaque rupture. Thus, VSMC plays an essential role in all stages of atherosclerosis. However, the regulatory mechanism of VSMC during the process of atherosclerosis is poorly understood. The applicant in the study of the Youth Fund of National Natural Science Foundation reported that poly(ADP-ribose)polymerase 1 (PARP1) was activated in atherosclerosis models, and exerted detrimental effects on cardiovascular functions through regulation of transcription factors. In the prelimilary experiments, we further demonstrated that PARP1 was activated in atherosclerotic plaque in patients. Activated PARP1 promoted phenotypic switching and calcification of VSMC. Transcription factors associated with VSMC functional regulation, including Myocardin and SRF, are target proteins of PARP1. These results indicate that PARP1 regulates VSMC function associated with atherosclerosis. In this project, we will investigate the effects of PARP1 on the function and phenotypic transition of VSMC during the process of atherosclerosis, and uncover the underlying mechanism. It will provide the experimental evidence and theoretical basis for the prevention and therapeutic progress of atherosclerotic diseases in the future.

血管平滑肌细胞（VSMC）的功能改变和表型转换会导致血管僵硬、血管狭窄、血栓形成、斑块破裂等动脉粥样硬化性疾病的发生，但其调控机制尚不明确。申请者在国家自然科学基金青年基金的研究中发现1型多聚ADP核糖合成酶（PARP1）在动脉粥样硬化模型中被激活，并通过调节转录因子来影响心脏和血管功能。围绕本项目开展的预实验进一步提示动脉粥样硬化患者血管斑块中PARP1被激活，活化的PARP1是调控VSMC表型转换和钙化的关键分子；而调节VSMC功能的重要转录因子Myocardin和SRF等是PARP1的靶蛋白，其活性受PARP1所调控。本项目据此推测：在动脉粥样硬化血管病变中，PARP1通过对重要转录因子的调节，影响VSMC的迁移、增殖、炎症、钙化等表型及功能的改变。本项目有望阐明PARP1调控动脉粥样硬化VSMC功能的分子机制，为以PARP1为靶点，重建血管稳态，防治动脉粥样硬化提供理论基础。

血管平滑肌细胞（VSMC）的功能改变和表型转换会导致血管僵硬、血管狭窄、血栓形成、斑块破裂等动脉粥样硬化性疾病的发生，但其调控机制尚不明确。ADP核糖化修饰是细胞内重要的蛋白质转录后修饰机制之一，这种修饰将NAD+分子中的ADP核糖共价连接到靶蛋白的一系列氨基酸基团上，形成单个ADP核糖或多聚ADP核糖链。ADP核糖化修饰由多聚ADP核糖合成酶（PARP）家族所催化。PARP家族包含17个成员，它们具有各自不同的结构区域，催化活性，亚细胞定位和生物学功能。PARP-1是表达于细胞核内的主要的PARP家族成员，广泛参与了生物体内一系列生理及病理过程。本项目系统研究了PARP-1对动脉粥样硬化血管平滑肌细胞功能及表型的调控作用和分子机制。在动脉粥样硬化患者血管斑块及动脉粥样硬化小鼠模型血管平滑肌中PARP-1被激活，PARP-1介导的多聚ADP核糖化水平显著增高。RNA-sequencing研究显示活化的PARP-1对血管平滑肌表型转换相关基因表达发挥关键调控作用。进一步研究显示调节VSMC功能表型的的重要转录因子Myocardin是PARP-1的靶蛋白，与其相互结合并被其多聚ADP核糖化修饰。Myocardin介导了PARP-1促血管平滑肌表型转换的作用。本项目揭示PARP-1及其介导的多聚ADP核糖化修饰对转录因子Myocardin的调节机制，为全面认识多聚ADP核糖化修饰的生物学功能，为以PARP-1为靶点，重建血管功能稳态，防治动脉粥样硬化性疾病提供理论和实验基础。研究过程中我们还发现了炎症转录因子IRF-1是调控动脉粥样硬化血管平滑肌细胞向泡沫细胞表型转换的另一重要因子，拓展了本课题在动脉粥样硬化血管平滑肌表型转换分子机制领域的研究方向。