Moesin磷酸化介导的细胞连接和骨架蛋白变化在GLP-1降低糖尿病大血管内皮通透性中的作用机制研究

Enhanced endothelial permeability is one of the early features of diabetic vascular disease. Glucagon-like peptide-1 (GLP-1) has been reported to protect endothelium-dependent vasodilatation. However, the effect of GLP-1 on diabetic macrovascular endothelial barrier function is still not clear. Our recent study indicated that glucagon-like peptide-1 (GLP-1) could contribute to the attenuation of skeleton rearrangement in endothelial cells incubated with advanced glycation end products (AGEs). We also found that targeted regulation of moesin could influence VE-cadherin translocation and attenuate endothelial barrier dysfunction.However,whether GLP-1 could affect the moesin, which subsequently.affect the vascular endothelial permeability mediated by moesin in diabetes is still not well defined. In this project, we firstly aim to investigate the roles of moesin in AGE induced changes of endothelial barrier function. Furthermore, we identify the effects of GLP-1 on moesin phosphorylation and endothelial permeability in endothelial cells incubated with AGEs by up-regulating or inhibiting related signal pathways. Meanwhile, the effects of GLP-1 on the arterial endothelial barrier function were also evaluated in diabetic rat model. Our study contributes to the illustration of roles of GLP-1 in preventing the increased diabetic macrovascular endothelial permeability.

血管内皮通透性增加是糖尿病血管病变的早期表现之一。研究表明胰高血糖素样肽-1(GLP-1)保护血管内皮舒张功能，但对糖尿病大血管内皮屏障功能的作用及机制仍不清楚。我们近期发现GLP-1显著缓解糖基化终末产物(AGEs)诱导的内皮细胞骨架重排，又证实具有膜骨架衔接作用的膜突蛋白(moesin)功能改变可影响血管内皮钙粘蛋白转位并减轻糖尿病血管内皮屏障功能损伤，而GLP-1能否调节moesin蛋白功能进而影响由moesin介导的糖尿病血管内皮通透性变化尚不清楚。本项目首先分析moesin蛋白在AGEs诱导血管内皮细胞屏障功能变化中的作用，继而激动或抑制相关信号通路,明确GLP-1对AGEs诱导血管内皮细胞moesin蛋白磷酸化和内皮通透性变化的影响及机制，并在糖尿病大鼠模型中证明GLP-1对动脉内皮屏障功能的作用。项目的开展为GLP-1防治糖尿病大血管内皮通透性增加提供依据。

糖尿病血管病变的早期表现之一是血管内皮通透性增加。研究表明胰高血糖素样肽-1(GLP-1)保护血管内皮舒张功能，但对糖尿病大血管内皮屏障功能的作用及机制仍不清楚。我们前期研究发现GLP-1显著缓解糖基化终末产物(AGEs)诱导的内皮通透性增加，究其分子机制可能为GLP-1可呈剂量依赖性降低AGE-BSA诱导的内皮细胞moesin和VE-cadherin蛋白磷酸化水平。通过构建moesin蛋白磷酸化位点突变型质粒，我们发现moesin蛋白在调节细胞骨架蛋白和黏附蛋白功能中发挥重要作用。同时我们发现GLP-1通过激动cAMP/PKA信号通路，进而抑制Rho/ROCK、p38/MAPK、PKCβ信号通路影响AGE-BSA诱导的内皮细胞moesin磷酸化水平，从而降低内皮细胞单层通透性。在动物实验中，利拉鲁肽可显著改善糖尿病大鼠主动脉内膜屏障功能，且利拉鲁肽治疗后可显著降低主动脉内膜层moesin蛋白磷酸化水平和RAGE、ROCK、p-p38、PKCβ表达水平。项目的完成首次揭示了GLP-1 对糖尿病大血管内皮屏障功能的影响及可能的调节机制，为进一步探究 GLP-1 在糖尿病血管系统中的作用提供理论依据和实验基础，终将为糖尿病动脉粥样硬化的早期防治提供新的思路。