Prothrombin Loading of Vascular Smooth Muscle Cell-Derived Exosomes Regulates Coagulation and Calcification
Prothrombin Loading of Vascular Smooth Muscle Cell-Derived Exosomes Regulates Coagulation and Calcification
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DOI：
10.1161/atvbaha.116.308886
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发表时间：
2017-03-01
影响因子：
8.7
通讯作者：
Shanahan, Catherine M.
中科院分区：
文献类型：
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作者：
Kapustin, Alexander N.;Schoppet, Michael;Shanahan, Catherine M.
华法林-药物华法林阻断维生素K依赖蛋白的羧化，并作为抗凝剂和血管钙化的促进剂。钙化抑制剂MGP由血管平滑肌细胞（VSMCs）产生的基质Gla [羧基谷氨酸]蛋白是华法林促进钙化作用的关键靶点;然而，还不清楚凝血级联中的蛋白质是否也在钙化中起作用。方法和结果-血管钙化由外来体启动，蛋白质组学分析显示，VSMC外泌体装载有含Gla的凝血因子：IX和X、PT（凝血酶原）以及蛋白质C和S。追踪Alexa 488标记的PT表明，外泌体负载通过直接结合外泌体表面上的外部化磷脂酰丝氨酸（PS）以及通过晚期内体/多泡体的内吞作用和再循环而发生。值得注意的是，PT Gla结构域和合成Gla结构域肽通过防止外泌体表面上的成核位点形成来抑制外泌体介导的VSMC钙化。PT沉积在钙化的血管中，血管钙化与循环PT水平呈负相关。此外，我们发现，血管平滑肌细胞外泌体诱导血栓形成的组织因子依赖性和PS-依赖的martens. Conclusions-γ-羧化凝血蛋白是有力的抑制剂，血管钙化表明华法林对这些因素的行动也有助于加速钙化的患者接受这种药物。VSMC外泌体连接钙化和凝血，作为外源性凝血途径的新型激活剂和在不存在含Gla抑制剂的情况下的钙化诱导剂。
Objective-The drug warfarin blocks carboxylation of vitamin K-dependent proteins and acts as an anticoagulant and an accelerant of vascular calcification. The calcification inhibitor MGP (matrix Gla [carboxyglutamic acid] protein), produced by vascular smooth muscle cells (VSMCs), is a key target of warfarin action in promoting calcification; however, it remains unclear whether proteins in the coagulation cascade also play a role in calcification.Approach and Results-Vascular calcification is initiated by exosomes, and proteomic analysis revealed that VSMC exosomes are loaded with Gla-containing coagulation factors: IX and X, PT (prothrombin), and proteins C and S. Tracing of Alexa488-labeled PT showed that exosome loading occurs by direct binding to externalized phosphatidylserine (PS) on the exosomal surface and by endocytosis and recycling via late endosomes/multivesicular bodies. Notably, the PT Gla domain and a synthetic Gla domain peptide inhibited exosome-mediated VSMC calcification by preventing nucleation site formation on the exosomal surface. PT was deposited in the calcified vasculature, and there was a negative correlation between vascular calcification and the levels of circulating PT. In addition, we found that VSMC exosomes induced thrombogenesis in a tissue factor-dependent and PS-dependent manner.Conclusions-Gamma-carboxylated coagulation proteins are potent inhibitors of vascular calcification suggesting warfarin action on these factors also contributes to accelerated calcification in patients receiving this drug. VSMC exosomes link calcification and coagulation acting as novel activators of the extrinsic coagulation pathway and inducers of calcification in the absence of Gla-containing inhibitors.