血管内皮钙黏蛋白（VE-cadherin）对内皮细胞巨噬细胞移动抑制因子（MIF）分泌的调节及NF-κB途径的作用

Vascular endothelial cadherin (VE-cadherin) is a major component of adherens junctions in endothelial cells. Recent studies have focused on the role of VE-cadherin in the regulation of endothelial barrier. Although a number of studies have noted that the change in VE-cadherin leads to endothelial hyperpermeability in inflammation, the role of VE-cadherin in modulating inflammatory cytokine and chemokine production remains unknown. Using high-throughput antibody array analysis, we demonstrated in our preliminary resulsts that disruption of VE-cadherin mediated endothelial cell-cell contact by function-blocking antibody (BV9) significantly regulated the secretion of macrophage migration inhibitory factor (MIF) in endothelial cells. In our project, we sought to investigate further the production of MIF by VE-cadherin disruption in endothelial cells and the possible role of NF-κB pathway by means of a specific anti-VE-cadherin monoclonal antibody (BV9) or small interfering RNA. Our study will uncover a novel role of VE-cadherin in the regulation of the secretion of MIF and elucidate the related mechanisms.This has important implications in understanding the role of VE-cadherin in the regulation of inflammation and immune response.

VE-cadherin 是血管内皮细胞间黏附连接的主要蛋白。许多研究表明炎症等因素刺激内皮细胞后发生由外向内的信号转导将信号传至细胞连接处，引起VE-cadherin变化导致内皮通透性增高。然而作为膜蛋白，VE-cadherin 是否具有向细胞内传递信号调节炎症细胞因子和趋化因子的作用尚未知。我们预实验通过 VE-cadherin 功能封闭性抗体（BV9）干预内皮细胞后采用高通量蛋白芯片技术对细胞上清液中细胞因子筛选，发现VE-cadherin破坏可明显调节巨噬细胞移动抑制因子（MIF）释放。本课题拟进一步通过VE-cadherin 功能性封闭抗体（BV9）、小干扰 RNA等方法研究 VE-cadherin 对 MIF 合成和分泌的调节及NF-κB相关机制。这对于认识 VE-cadherin 调节炎症和免疫反应具有重要意义。

VE-cadherin 是血管内皮细胞间黏附连接的主要蛋白。许多研究表明炎症等因素刺激内皮细胞后发生由外向内的信号转导将信号传至细胞连接处，引起VE-cadherin变化导致内皮通透性增高。然而作为膜蛋白，VE-cadherin 是否具有向细胞内传递信号调节炎症细胞因子和趋化因子的作用尚未知。本项目通过体内外研究发现，破坏VE-cadherin介导的血管内皮屏障可促进血管通透性和炎症，机制涉及NF-κB 信号通路部分介导的MIF合成和释放。首先，体外实验应用VE-cadherin封闭抗体，用蛋白芯片筛查发现可明显促进MIF释放。应用siRNA方法敲低VE-cadherin也得到同样结果。VE-cadherin过表达抑制LPS刺激引起的MIF分泌。在体内实验中，小鼠注射VE-cadherin单抗干预VE-cadherin组成的细胞连接可引起肺血管通透性增加和肺部炎症，同时血浆中MIF水平增高。而采用MIF中和性抗体后，可部分减轻血管渗漏和肺部炎症。在进一步的机制研究中，发现Scr激酶介导的NF-κB激活在VE-cadherin调节MIF合成和分泌中具有重要作用，而与VE-cadherin结合的β-catenin含量降低，提示其并未发生核转位而参与调节MIF合成。总之，本项目研究的发现，对认识 VE-cadherin 在调节炎症和免疫反应中的作用具有重要意义。