Loss of endothelial barrier function contributes to the pathophysiology of many inflammatory diseases. Coagulation factor XI (FXI) plays a regulatory role in inflammation. Although activation of FXI increases vascular permeability in vivo, the mechanism by which FXI or its activated form FXIa disrupts endothelial barrier function is unknown. We investigated the role of FXIa in human umbilical vein endothelial cell (HUVEC) or human aortic endothelial cell (HAEC) permeability. The expression patterns of vascular endothelial (VE)-cadherin and other proteins of interest were examined by western blot or immunofluorescence. Endothelial cell permeability was analyzed by Transwell assay. We demonstrate that FXIa increases endothelial cell permeability by inducing cleavage of the VE-cadherin extracellular domain, releasing a soluble fragment. The activation of a disintegrin and metalloproteinase 10 (ADAM10) mediates the FXIa-dependent cleavage of VE-cadherin, because adding an ADAM10 inhibitor prevented the cleavage of VE-cadherin induced by FXIa. The binding of FXIa with plasminogen activator inhibitor 1 and very low–density lipoprotein receptor on HUVEC or HAEC surfaces activates vascular endothelial growth receptor factor 2 (VEGFR2). The activation of VEGFR2 triggers the mitogen-activated protein kinase (MAPK) signaling pathway and promotes the expression of active ADAM10 on the cell surface. In a pilot experiment using an established baboon model of sepsis, the inhibition of FXI activation significantly decreased the levels of soluble VE-cadherin to preserve barrier function. This study reveals a novel pathway by which FXIa regulates vascular permeability. The effect of FXIa on barrier function may be another way by which FXIa contributes to the development of inflammatory diseases.

中文翻译：

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凝血因子 XI 在体外和体内调节内皮细胞通透性和屏障功能


内皮屏障功能的丧失会导致许多炎症性疾病的病理生理学。凝血因子 XI （FXI） 在炎症中起调节作用。尽管 FXI 的激活增加了体内血管通透性，但 FXI 或其激活形式 FXIa 破坏内皮屏障功能的机制尚不清楚。我们研究了 FXIa 在人脐静脉内皮细胞 （HUVEC） 或人主动脉内皮细胞 （HAEC） 通透性中的作用。通过 western blot 或免疫荧光检测血管内皮 （VE）-钙粘蛋白和其他目标蛋白的表达模式。通过 Transwell 法分析内皮细胞通透性。我们证明 FXIa 通过诱导 VE-钙粘蛋白胞外结构域的切割来增加内皮细胞通透性，释放可溶性片段。解整合素和金属蛋白酶 10 （ADAM10） 的激活介导了 VE-钙粘蛋白的 FXIa 依赖性裂解，因为添加 ADAM10 抑制剂阻止了 FXIa 诱导的 VE-钙粘蛋白裂解。FXIa 与 HUVEC 或 HAEC 表面的纤溶酶原激活物抑制剂 1 和极低密度脂蛋白受体的结合激活血管内皮生长受体因子 2 （VEGFR2）。VEGFR2 的激活触发丝裂原活化蛋白激酶 （MAPK） 信号通路，并促进细胞表面活性 ADAM10 的表达。在使用已建立的脓毒症狒狒模型的试点实验中，对 FXI 激活的抑制显着降低了可溶性 VE-钙粘蛋白的水平，以保持屏障功能。本研究揭示了 FXIa 调节血管通透性的新途径。 FXIa 对屏障功能的影响可能是 FXIa 导致炎症性疾病发展的另一种方式。