Schuepbach Reto A, Feistritzer Clemens, Fernández José A, Griffin John H, Riewald Matthias
Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA.
Thromb Haemost. 2009 Apr;101(4):724-33. doi: 10.1160/th08-10-0632.
Protease activated receptor-1 (PAR1) mediates barrier protective signalling of activated protein C (APC) in human endothelial cells in vitro and may contribute to APC's beneficial effects in patients with severe sepsis. Mouse models are of key importance for translational research but species differences may limit conclusions for the human system. We analysed whether mouse APC can cleave, activate and induce signalling through murine PAR1 and tested in newly established mouse models if long-term infusion of APC prevents from vascular leakage. Cell surface immunoassays demonstrated efficient cleavage of endogenous murine endothelial PAR1 by either murine or human APC. Pharmacological concentrations of APC of either species had powerful barrier protective effects on cultured murine endothelial cells that required PAR1 cleavage. Vascular endothelial growth factor-mediated hyperpermeability in the skin was reduced by either endogenously generated as well as directly infused recombinant mouse APC in wild-type mice. However APC did not significantly alter the vascular barrier function in PAR1-deficient mice. In endotoxin-challenged mice, infused APC significantly prevented from pulmonary fluid accumulation in the wild-type mice but not in mice lacking PAR1. Our results directly show that murine APC cleaves and signals through PAR1 in mouse endothelial cells. APC reduces vascular permeability in mouse models and PAR1 plays a major role in mediating these effects. Our data in vitro and in vivo support the paradigm that PAR1 contributes to protective effects of APC on vascular barrier integrity in sepsis.
蛋白酶激活受体-1(PAR1)在体外介导人内皮细胞中活化蛋白C(APC)的屏障保护信号传导,可能有助于APC对严重脓毒症患者产生有益作用。小鼠模型对于转化研究至关重要,但物种差异可能会限制对人类系统得出的结论。我们分析了小鼠APC是否能通过鼠PAR1进行切割、激活并诱导信号传导,并在新建立的小鼠模型中测试了长期输注APC是否能防止血管渗漏。细胞表面免疫分析表明,鼠或人APC均可有效切割内源性鼠内皮PAR1。两种物种的药理学浓度的APC对培养的鼠内皮细胞均具有强大的屏障保护作用,这需要PAR1的切割。在野生型小鼠中,内源性产生的以及直接输注的重组鼠APC均可降低血管内皮生长因子介导的皮肤高通透性。然而,APC并未显著改变PAR1缺陷小鼠的血管屏障功能。在内毒素攻击的小鼠中,输注的APC可显著防止野生型小鼠肺内液体蓄积,但对缺乏PAR1的小鼠则无此作用。我们的结果直接表明,鼠APC在小鼠内皮细胞中通过PAR1进行切割并发出信号。APC可降低小鼠模型中的血管通透性,PAR1在介导这些作用中起主要作用。我们的体外和体内数据支持PAR1有助于APC对脓毒症中血管屏障完整性产生保护作用这一范例。