肝肺综合征（HPS）机制不明、防治困难，针对其核心改变“肺内微血管扩张（IPVD）”的病理进程进行干预是防治研究的主要策略。既往针对IPVD的机制研究主要集中在肺微血管内皮细胞（PMVECs）异常增殖、肌样分化及其调控通路上；我们在前期基金研究工作中，发现 “PMVECs极性丢失”可能是其异常增殖、肌样分化的上游关键事件，值得深入研究。进一步预筛实验提示PTEN/ANXA2通路异常致极性分子开关Cdc42失活可能是“PMVECs极性丢失”的主要调控通路，是临床转化更优干预靶点。因此本课题拟建立大鼠HPS和PMVECs模型，采用光遗传学、基因转染、FRET、激光共聚焦、定量PCR、siRNA、质谱等技术，阐明PTEN/ANXA2-Cdc42调控PMVECs细胞极性丢失在IPVD进程中的作用，为制定以Cdc42为靶点、诱导“PMVECs的极性维持”以获得更佳保护的HPS治疗新策略奠定理论基础。

Poorly defining the mechanisms responsible for the intrapulmonary microvascular dilation (IPVD) results in no effective medical therapies of hepatopulmonary syndrome (HPS). Although the cellular pathways that regulate PMVEC proliferation, migration and differentiation have been the focus of recent studies, the further clinical translation is ineffective. It is necessary to establish a new strategy based on the study of the discovery of superior upstream therapeutic targets. Our previous study indicated that “the loss of cell polarity of PMVECs” might be the key upsream event in the pathogenesis of IPVD. Further, our preliminary experiments suggested that aberrant PTEN/ANXA2 signaling leading to the inactivation of Cdc42 (molecular switch of cell polarity) could be the critical regulatory pathway. Taking cell polarity into account, its maintenance plays an important role in multiple cellular functions, including cell proliferation, differentiation and migration. In this study, models of HPS and PMVECs will be established. Recombinant adenovirus transfection, FRET, laser confocal microscopy, real-time PCR, siRNA and mass spectrometry will be applied to identify the role of PTEN/ANXA2-Cdc42 pathway regulating the loss of PMVECs plarity in the pathogenesis of IPVD of HPS, to explore whether the regulation of Cdc42 activity inducts the maintenance of PMVECs polarity is the more protective and new therapeatic strategies for HPS treatment.