Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA.
Department of Surgery, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA.
Cardiovasc Res. 2020 Jul 1;116(8):1525-1538. doi: 10.1093/cvr/cvz238.
Microvesicles (MVs) conduct intercellular communication and impact diverse biological processes by transferring bioactive cargos to other cells. We investigated whether and how endothelial production of MVs contribute to vascular dysfunction during inflammation.
We measured the levels and molecular properties of endothelial-derived MVs (EC-MVs) from mouse plasma following a septic injury elicited by cecal ligation and puncture, as well as those from supernatants of cultured endothelial cells stimulated by inflammatory agents including cytokines, thrombin, and complement 5a. The mouse studies showed that sepsis caused a significant increase in total plasma vesicles and VE-cadherin+ EC-MVs compared to sham control. In cultured ECs, different inflammatory agents caused diverse patterns of EC-MV production and cargo contents. When topically applied to endothelial cells, EC-MVs induced a cytoskeleton-junction response characterized by myosin light chain phosphorylation, contractile fibre reorganization, VE-cadherin phosphorylation, and adherens junction dissociation, functionally measured as increased albumin transendothelial flux and decreased barrier resistance. The endothelial response was coupled with protein tyrosine phosphorylation promoted by MV cargo containing c-Src kinase, whereas MVs produced from c-Src deficient cells did not exert barrier-disrupting effects. Additionally, EC-MVs contribute to endothelial inflammatory injury by promoting neutrophil-endothelium adhesion and release of neutrophil extracellular traps containing citrullinated histones and myeloperoxidase, a response unaltered by c-Src knockdown.
Endothelial-derived microparticles cause endothelial barrier dysfunction by impairing adherens junctions and activating neutrophils. The signalling mechanisms underlying the endothelial cytoskeleton-junction response to EC-MVs involve protein phosphorylation promoted by MV cargo carrying c-Src. However, EC-MV-induced neutrophil activation was not dependent on c-Src.
微泡（MVs）通过将生物活性货物转移到其他细胞来进行细胞间通讯并影响多种生物过程。我们研究了内皮细胞产生的 MV 是否以及如何在炎症期间导致血管功能障碍。
我们测量了盲肠结扎和穿刺引起的脓毒症损伤后小鼠血浆中内皮衍生的 MV（EC-MVs）的水平和分子特性，以及炎性刺激物（包括细胞因子、凝血酶和补体 5a）刺激的培养内皮细胞上清液中的 MV。小鼠研究表明，与假手术对照相比，败血症导致总血浆囊泡和 VE-钙粘蛋白+ EC-MVs 显著增加。在培养的 EC 中，不同的炎症刺激物导致不同的 EC-MV 产生模式和货物含量。当局部应用于内皮细胞时，EC-MVs 诱导肌球蛋白轻链磷酸化、收缩纤维重排、VE-钙粘蛋白磷酸化和黏附连接解离的细胞骨架-连接反应，功能上表现为白蛋白跨内皮通量增加和屏障阻力降低。内皮反应与 MV 货物中包含的 c-Src 激酶促进的蛋白酪氨酸磷酸化相关，而来自 c-Src 缺陷细胞的 MV 则不会产生破坏屏障的作用。此外，EC-MVs 通过促进中性粒细胞-内皮细胞粘附和释放含有瓜氨酸化组蛋白和髓过氧化物酶的中性粒细胞细胞外陷阱来促进内皮炎症损伤，该反应不受 c-Src 敲低的影响。
内皮衍生的微泡通过破坏黏附连接和激活中性粒细胞导致内皮屏障功能障碍。内皮细胞对 EC-MVs 的细胞骨架-连接反应的信号机制涉及 MV 货物携带的 c-Src 促进的蛋白磷酸化。然而，EC-MV 诱导的中性粒细胞激活不依赖于 c-Src。
