E3泛素连接酶Hrd1在ox-LDL所致血管内皮细胞损伤中的作用与机制研究

Endothelial cell injury is an initial step of the pathogenesis of atherosclerosis (AS). oxLDL is now considered to play a fundamental role in endothelium injury. However, the molecular mechanism of endothelial cell injury is unclear. Our preliminary results showed that levels of E3 ubiquitin ligase Hrd1 were significantly decreased in atherosclerotic plaques compared to normal artery. oxLDL dose-dependently decreased the expression of Hrd1 but increased the expression of LOX-1 of endothelial cells. Further studies showed that Hrd1 directly interactd with LOX-1 and mediated LOX-1 ubiquitylation, which was regulated by oxLDL treatment. Overexpression of transcription factor KLF2 reversed the decrease of Hrd1 expression in endothelial cells induced by oxLDL. As a result, we speculated that Hrd1 down-regulating LOX-1 expression played an important role in ox-LDL-induced endothelial cell injuries in KLF2-dependent pathway. In this study, we aim to demonstrate the effect of Hrd1 on ox-LDL-induced endothelial cell injuries using a series of in vivo and in vitro technology, including the establishment of Hrd1 transgenic and knockout mice. And we will further explore the molecular mechanism of Hrd1 on ox-LDL-induced endothelial cell injuries, trying to provide a potential target for the treatment of AS in the future.

内皮细胞的损伤是动脉粥样硬化（atherosclerosis，AS）发生的始动环节， oxLDL是其主要的损伤因素，但具体分子机制仍不清楚。本课题前期研究显示，动脉粥样斑块中E3泛素连接酶Hrd1的表达显著降低；oxLDL剂量依赖性下降内皮细胞中HRD1的表达而上调LOX-1的表达。进一步研究显示，Hrd1可与LOX-1特异性结合，介导LOX-1泛素化修饰，且受到oxLDL的调控。过表达转录因子KLF2能逆转oxLDL造成的Hrd1表达下降。由此，我们推测，oxLDL通过KLF2抑制Hrd1的表达，进而上调LOX-1的表达，从而在oxLDL诱导的内皮细胞损伤中发挥重要作用。该项目旨在细胞和模式动物水平上，借助于各种分子生物学和转基因小鼠的技术手段，研究Hrd1在oxLDL诱导的内皮细胞损伤中作用。本项目的完成将有助于阐明E3泛素连接酶Hrd1在oxLDL诱导的内皮细胞损伤中的内在机制，并为

内皮细胞（Endothelial cell ，EC）的损伤是动脉粥样硬化发生的始动环节，oxLDL是其主要的损伤因素，但具体分子机制仍不清楚。本课题组通过前期研究结果推测oxLDL可能通过KLF2抑制 Hrd1的表达，进而上调LOX-1的表达，从而在oxLDL诱导的内皮细胞损伤中发挥重要作用。课题实施通过运用人群、细胞等多层面，验证Hrd1在 oxLDL诱导的ECs损伤中作用。. 项目执行期共发表论文5篇，其中SCI论文4篇。举办国内学术会议4次，参加国内外学术交流5人次。项目实施过程顺利，完成预期目标。