USP10介导ACE2去泛素化修饰对肺血管内皮保护机制及其病理生理意义

肺动脉高压（PAH）是一种高致死率的心肺血管疾病。在PAH发病过程中，血管紧张素转化酶2（ACE2）对内皮功能稳态发挥重要调控作用。我们前期研究发现双微体蛋白2（MDM2）促进ACE2泛素化导致内皮功能障碍。但是对于ACE2去泛素化酶及分子机制尚未见报道。我们利用生物信息学发现去泛素化酶USP10与ACE2具有显著相关性。在ACE2泛素化实验中发现低氧诱导ACE2泛素化水平增加，USP10表达却显著降低。据此提出假说：去泛素化酶USP10促进ACE2去泛素化，调控内皮功能。为此，本项目拟采用表观遗传学和系统生物学等方法探讨USP10对ACE2蛋白修饰和对肺血管内皮细胞作用机制。最后，在体构建基因点突变ACE2 K788R去泛素化转基因小鼠，揭示USP10介导ACE2去泛素化机制及在体ACE2泛素化位点突变对肺血管内皮的保护作用，阐明USP10-ACE2通路的激活在肺动脉高压临床治疗的意义。

Pulmonary arterial hypertension (PAH) is a cardiopulmonary vascular disease with high mortality. Angiotensin-converting enzyme 2 (ACE2) are crucial in endothelial homeostasis of PAH. Our previous study found that murine double minute 2 (MDM2) promoted ACE2 ubiquitination and led to endothelial dysfunction. However, ACE2 deubiquitination enzyme and its molecular mechanism have not been reported. Using bioinformatics, we found that deubiquitination enzyme USP10 was significantly correlated with ACE2. Furthermore, we found that USP10 was significantly reduced in the hypoxia-induced ubiquitination of ACE2. Therefore, it is hypothesized that USP10 promotes ACE2 deubiquitination and regulates endothelial function. This project intends to explore the protein modification relationship between USP10 and ACE2 and the mechanism of pulmonary vascular endothelium by using epigenetics and systems biology methods. Finally, we created deubiquitination transgenic mice harboring ACE2 ubiquitination site mutant, revealing the mechanism of USP10 mediated ACE2 deubiquitination and the protective effect of ACE2 ubiquitination site mutation on pulmonary vascular endothelium in vivo. Also, we will clarify the significance of the USP10-ACE2 pathway in the clinical treatment of PAH.