ROBO4经S-palm修饰介导TGF-β受体内吞促肺动脉高压内皮间质化的作用及机制研究

肺动脉高压（PH）是一类以肺血管阻力和肺动脉压力升高为特征的肺血管病变，血管重塑是其重要病理基础。肺动脉内皮细胞受外界病理刺激发生内皮间质化（EndMT）导致内皮功能失调、平滑肌样细胞沉积，促肺血管重塑。由此，明确肺动脉EndMT的发生机制对抑制PH血管重塑具有重要意义。项目前期发现内皮特异性蛋白ROBO4在PH肺动脉内皮高表达，且与p-TGFβRI共定位于质膜；机制研究显示沉默ROBO4使p-TGFβRI无法内吞，进而抑制Smad2/3磷酸化，最终缓解EndMT，提示ROBO4介导p-TGFβRI内吞在PH发生发展中发挥重要作用；进一步发现半胱氨酸棕榈酰化修饰调控ROBO4定位于质膜，在TGFβRI内吞过程发挥关键作用。基于此，项目拟利用转基因敲除鼠、特异性抑制剂结合转录组学、免疫共沉淀等技术，阐明ROBO4对PH肺动脉EndMT的调控作用及分子机制，为寻找PH治疗新策略提供理论依据。

Pulmonary hypertension (PH) is a kind of pulmonary vascular disease, characterized by increased pulmonary vascular resistance and pulmonary artery pressure. Pulmnary vascular remodeling is an important pathological basis of PH. Stimulated by external pathological factors, pulmonary artery endothelial cells undergoes endothelial-mesenchymal transition (EndMT) to lead to endothelial dysfunction and smooth muscle-like cells deposition, which promotes pulmonary vascular remodeling. Therefore, it is significant to clarify the mechanism of pulmonary artery EndMT for blocking PH vascular remodeling. In the early stage of this project, it was found that the endothelium-specific protein ROBO4 is highly expressed in pulmonary artery endothelium of PH and co-localizes with p-TGFβRI on the plasma membrane; further studies have shown that ROBO4 knockdown prevents p-TGFβRI from being endocytosed, thereby inhibiting Smad2/3 phosphorylation, and ultimately alleviating EndMT. It is suggested that ROBO4 mediates endocytosis of p-TGFβRI to play an important role in the occurrence and development of PH. Moreover, it was found that cysteine palmitoylation modifies the localization ROBO4 on the plasma membrane and plays a key role in the process of TGFβRI endocytosis. Based on this preliminary foundation, the project intends to use transgenic knockout mice and specific inhibitor combined with transcriptomics, immunoprecipitation and other technologies to clarify the role and molecular mechanism of ROBO4 on pulmonary artery EndMT of PH, and provide a theoretical basis for finding new strategies for PH treatment.