组织蛋白酶Cathepsin L促进BMPR2降解参与肺动脉高压内皮损伤的作用及机制

Pulmonary arterial hypertension (PAH) is known as cardiovascular cancer with very poor prognosis. Endothelium injury is the critical step to initiate the process of PAH. Bone morphogenetic protein type 2 receptor (BMPR2) plays a key role in maintaining endothelial cell function, but the regulatory mechanism of BMPR2 expression is still unclear. We found that cathepsin L (CatL) levels were significantly elevated in PAH patients and animal models. CatL could bind directly to BMPR2 in pulmonary arterial endothelial cell, while siRNA knock down of CatL could rescue BMPR2 expression and protect apoptosis meanwhile. Therefore we assume that CatL is a key protease that promotes the degradation of BMPR2 and plays an important role in endothelium injury of PAH. In this study, by using gene knockout, gene overexpression and co-immunoprecipitation stratagemwe, we planned to confirm the effect of CatL on pulmonary vascular endothelium injury , and then investigate the regulation of endothelial BMPR2 expression by CatL, finally reveal the specific mechanism that CatL promotes degradation of BMPR2 through the ubiquitination and lysosomal pathway. These results will help to reveal the role of cathepsin in PAH, deepen the understanding of BMPR2 expression regulation, and provide a new experimental basis for the development of therapeutic drugs targeting on CatL/BMPR2 pathway.

肺动脉高压（PAH）号称心血管肿瘤，预后极差。内皮损伤是诱发PAH的始动环节，骨形成蛋白2型受体（BMPR2）在维持内皮功能中发挥关键作用，但其表达的调节机制仍不清楚。我们前期研究发现：PAH患者和动物模型中组织蛋白酶Cathepsin L（CatL）水平显著升高；肺动脉内皮细胞中CatL可直接结合BMPR2；沉默CatL后可恢复BMPR2表达，保护细胞凋亡。因此推测，CatL是促进内皮BMPR2降解的关键蛋白酶，在肺动脉高压内皮损伤中发挥重要作用。本研究拟采用基因敲除、慢病毒转染及免疫共沉淀等手段①确证CatL在肺动脉高压内皮损伤中的作用；②观察CatL对内皮BMPR2表达的调节；③揭示CatL通过泛素化、溶酶体途径促进BMPR2降解的具体机制。研究结果将为揭示组织蛋白酶的作用、深化BMPR2表达调控机制的认识及以CatL/BMPR2为靶点开发药物提供新的实验依据。

肺动脉高压(PAH)号称心血管肿瘤，预后极差。内皮损伤是诱发PAH的始动环节，骨形成蛋白2型受体(BMPR2)在维持内皮功能中发挥关键作用，但其表达的调节机制仍不清楚。我们前期研究发现：PAH患者和动物模型中组织蛋白酶Cathepsin L(CatL)水平显著升高；肺动脉内皮细胞中CatL可直接结合BMPR2；沉默CatL后可恢复BMPR2表达，保护细胞凋亡。因此推测，CatL是促进内皮BMPR2降解的关键蛋白酶，在肺动脉高压内皮损伤中发挥重要作用。本研究拟采用慢病毒转染及免疫共沉淀等手段1）确证CatL在肺动脉高压内皮损伤中的作用；2）观察CatL对内皮BMPR2表达的调节；3）揭示CatL通过溶酶体途径促进BMPR2降解的具体机制。.本项目通过在人、动物和细胞三个方面的实验证明升高的CatL参与肺血管内皮损伤，是肺动脉高压发生发展的重要病理机制，从而揭示组织蛋白酶在肺动脉高压中的作用。阐明CatL可通过诱导肺动脉内皮功能障碍导致肺动脉高压的发生，其机制是通过促进BMPR2溶酶体降解，进而导致BMPR2信号通路功能缺失，从而导致内皮细胞过度迁移及凋亡实现的。加深了我们对BMPR2信号通路参与肺动脉高压血管损伤的理解。同时初步确证抑制CatL对肺动脉高压的防治作用。研究结果将为揭示组织蛋白酶的作用、深化BMPR2表达调控机制的认识及以CatL/BMPR2为靶点开发药物提供新的实验依据。