内皮细胞中PDI的巯基硫化修饰在主动脉夹层中的作用及机制研究

主动脉夹层（AD）是一类十分凶险的疾病，血管内膜损伤作为其发生的始动因素，在AD中至关重要，H2S介导的巯基硫化修饰能够影响蛋白功能，参与多种疾病的调控，但其在AD中的作用尚不清楚。二硫键异构酶（PDI）与内质网功能密切相关，其是否参与AD尚无报道。预实验显示，AD患者和AD模型小鼠血浆H2S水平下降；质谱结合生物信息学分析提示内皮细胞中PDI是潜在的巯基硫化修饰靶点；AD小鼠血管组织以及AngII刺激的内皮细胞中PDI巯基硫化修饰水平下降；给予H2S供体能增加PDI巯基硫化修饰，改善AngII导致的内皮细胞内质网应激；PDI修饰位点突变后H2S促进其蛋白构象变化作用消失。本项目将从动物、细胞和分子水平，采用蛋白质组学和分子生物学等手段，验证假说：PDI巯基硫化修饰下降会影响其活性，导致内质网应激，介导内皮损伤和AD发生。本项目可揭示内皮损伤和AD发生新机制，为AD防治提供新靶点和策略。

Aortic dissection (AD) is a kind of extremely dangerous disease. Vascular intimal injury, as the initiating factor, plays an important role in AD. Protein S-sulfhydration mediated by hydrogen sulfide (H2S) could regulate numerous protein function and activity and involve in many diseases. However, the precise role of S-sulfhydration in AD remains unclear. Protein disulfide isomerase (PDI) is essential for endoplasmic reticulum function, but its role in AD remains unknown. Our preliminary results showed that the plasma H2S level was decreased in AD patients and mice. Mass spectrum based bioinformatics analysis suggested PDI as a potential S-sulfhydrated target in endothelium. The S-sulfhydration of PDI was significantly decreased in AD mice and AngII-stimulated endothelial cells. H2S donor (GYY4137) treatment could reverse the decreased S-sulfhydration of PDI and improve ER stress induced by AngII. Mutation of S-sulfhydration sites abolished the effect of H2S on the PDI conformational transformation. In the present proposal, we hypothesize that S-sulfhydration of PDI could alter its activity to regulate ER stress, further mediating the endothelial dysfunction and AD. This project will test the hypothesis in combination with proteomics and molecular biology methods both in vivo and in vitro. The study may reveal the new mechanism of AD and vascular intimal injury, which will provide new targets and strategies for the prevention and treatment of AD.