新生鼠低氧性肺动脉高压中RAGE通过脂筏结构调节内皮细胞自噬的研究

Endothelial cell dysfunction plays a key role in the pathogenesis of pulmonary vascular remodeling and pulmonary arterial hypertension (PAH). Advanced glycation end products receptor (RAGE) has been reported to be involved in the regulation of endothelial cell function. Our previous study showed that plasma RAGE is a biomarker participating in acute lung injury, however, the underlying molecular mechanism remains unknown. From the literature, the autophagy level in the lung tissue is increased in PAH patients, and autophagic protein LC3Ⅱ is colocalized with Egr-1 in caveolae, a type of specialized membrane microdomain also termed as ‘lipid rafts’, which is enriched with cholesterol and participates in signaling of certain membrane-bound proteins. Meanwhile, the activated form of RAGE is also localized in the caveolae, suggesting a potential association RAGE signalling and LC3Ⅱ functioning within the specialized membrane domain caveolae. In our previous studies, we found that apoptosis could be induced by either inhibition of autophagy or disruption of calveolae in endothelial cells, suggesting the protective roles of autophagy and the integrity of caveolae during PAH-induced injury. Based on the evidence from the laboratory and the literature, we thus hypothesize that activated RAGE and LC3Ⅱ colocalize and interact in the lipid rafts/caveolae domains during PAH, and protect the function of endothelial cell. This proposed project aims to investigate the role and the mechanism of RAGE and lipid rafts in regulation of autophagy in pulmonary vascular endothelial cells, and whether the lipid rafts/caveolae is the functional domains of RAGE in regulating autophagy level. Our laboratory strategies include knock-out of RAGE gene expression, disruption of the integrity of caveolae domain, and manipulation of autophagy levels, etc. Our findings will provide experimental evidence to explore new druggable molecular targets for hypoxia-induced PAH.

内皮细胞功能紊乱是肺血管重构和肺动脉高压（PAH）发病的关键环节。我们发现晚期糖基化终末产物受体（RAGE）是参与急性肺血管损伤的早期生物学标记，但具体机制不明。文献中，PAH病人肺组织的自噬水平升高，自噬相关蛋白LC3Ⅱ与Egr-1因子共定位于细胞膜特殊结构域脂筏caveolae；而RAGE可通过激活自噬保护内皮功能，活化RAGE也定位于caveolae，提示RAGE信号转导及LC3Ⅱ功能均与caveolae有关。我们也发现抑制自噬与破坏脂筏均可诱导内皮细胞凋亡，提示自噬和脂筏结构有保护内皮细胞的作用。本研究中，我们将根据活化RAGE与LC3Ⅱ共定位于脂筏结构激活自噬，保护内皮细胞的科学假说，通过RAGE敲除、破坏脂筏结构完整性、调控自噬等手段，探讨低氧性PAH中RAGE是否通过影响自噬干预肺血管重构，以及脂筏是否为RAGE调控自噬的特定功能区域，寻找可有效干预低氧性PAH的新治疗靶标。

内皮细胞功能紊乱是肺血管重构和肺动脉高压（PAH）发病的关键环节。我们发现晚期糖基化终末产物受体（RAGE）是参与急性肺血管损伤的早期生物学标记，但具体机制不明。文献中，PAH病人肺组织的自噬水平升高，自噬相关蛋白LC3Ⅱ与Egr-1因子共定位于细胞膜特殊结构域脂筏caveolae；而RAGE可通过激活自噬保护内皮功能，活化RAGE也定位于caveolae，提示RAGE信号转导及LC3Ⅱ功能均与caveolae有关。我们也发现抑制自噬与破坏脂筏均可诱导内皮细胞凋亡，提示自噬和脂筏结构有保护内皮细胞的作用。本研究中，我们将根据活化RAGE与LC3Ⅱ共定位于脂筏结构激活自噬，保护内皮细胞的科学假说，通过RAGE敲除、破坏脂筏结构完整性、调控自噬等手段，探讨低氧性PAH中RAGE是否通过影响自噬干预肺血管重构，以及脂筏是否为RAGE调控自噬的特定功能区域，寻找可有效干预低氧性PAH的新治疗靶标。