Ribera Jordi, Pauta Montse, Melgar-Lesmes Pedro, Córdoba Bernat, Bosch Anna, Calvo Maria, Rodrigo-Torres Daniel, Sancho-Bru Pau, Mira Aurea, Jiménez Wladimiro, Morales-Ruiz Manuel
Biochemistry and Molecular Genetics Department, Hospital Clínic of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Barcelona, Spain.
Advanced Optic Microscopy Unit, School of Medicine, Centres Científics i Tecnològics, University of Barcelona, Barcelona, Spain.
Am J Physiol Gastrointest Liver Physiol. 2017 Nov 1;313(5):G492-G504. doi: 10.1152/ajpgi.00428.2016. Epub 2017 Aug 10.
Rising evidence points to endothelial-to-mesenchymal transition (EndMT) as a significant source of the mesenchymal cell population in fibrotic diseases. In this context, we hypothesized that liver endothelial cells undergo EndMT during fibrosis progression. Cirrhosis in mice was induced by CCl A transgenic mouse expressing a red fluorescent protein reporter under the control of Tie2 promoter (Tie2-tdTomato) was used to trace the acquisition of EndMT. Sinusoidal vascular connectivity was evaluated by intravital microscopy and high-resolution three-dimensional confocal microscopy. A modest but significant fraction of liver endothelial cells from both cirrhotic patients and CCl-treated Tie2-tdTomato mice acquired an EndMT phenotype characterized by the coexpression of CD31 and α-smooth muscle actin, compared with noncirrhotic livers. Bone morphogenetic protein-7 (BMP-7) inhibited the acquisition of EndMT induced by transforming growth factor-β1 (TGF-β1) treatment in cultured primary mouse liver endothelial cells from control mice. EndMT was also reduced significantly in vivo in cirrhotic Tie2-tdTomato mice treated intraperitoneally with BMP-7 compared with untreated mice (1.9 ± 0.2 vs. 3.8 ± 0.3%, respectively; < 0.05). The decrease of EndMT in cirrhotic livers correlated with a significant decrease in liver fibrosis ( < 0.05) and an improvement in the vascular disorganization rate ( < 0.05). We demonstrated the acquisition of the EndMT phenotype by a subpopulation of endothelial cells from cirrhotic livers in both animal models and patients. BMP-7 treatment decreases the occurrence of the EndMT phenotype and has a positive impact on the severity of disease by reducing fibrosis and sinusoidal vascular disorganization. A subpopulation of liver endothelial cells from cirrhotic patients and mice with liver fibrosis undergoes endothelial-to-mesenchymal transition. Liver endothelial cells from healthy mice could transition into a mesenchymal phenotype in culture in response to TGF-β1 treatment. Fibrotic livers treated chronically with BMP-7 showed lower EndMT acquisition, reduced fibrosis, and improved vascular organization.
越来越多的证据表明，内皮-间充质转化（EndMT）是纤维化疾病中间充质细胞群的重要来源。在此背景下，我们推测肝内皮细胞在纤维化进展过程中会发生EndMT。通过CCl诱导小鼠肝硬化。使用在Tie2启动子控制下表达红色荧光蛋白报告基因的转基因小鼠（Tie2-tdTomato）来追踪EndMT的发生。通过活体显微镜和高分辨率三维共聚焦显微镜评估肝血窦血管连通性。与非肝硬化肝脏相比，肝硬化患者和CCl处理的Tie2-tdTomato小鼠的肝内皮细胞中有一小部分但显著比例获得了以CD31和α-平滑肌肌动蛋白共表达为特征的EndMT表型。骨形态发生蛋白-7（BMP-7）抑制了来自对照小鼠的原代培养小鼠肝内皮细胞中由转化生长因子-β１（TGF-β1）处理诱导的EndMT的发生。与未处理的小鼠相比，腹腔注射BMP-7的肝硬化Tie2-tdTomato小鼠体内的EndMT也显著减少（分别为1.9±0.2%和3.8±0.3%；P<0.05）。肝硬化肝脏中EndMT的减少与肝纤维化的显著降低（P<0.05）和血管紊乱率的改善（P<0.05）相关。我们在动物模型和患者中均证明了肝硬化肝脏的内皮细胞亚群获得了EndMT表型。BMP-7治疗可减少EndMT表型的发生，并通过减少纤维化和肝血窦血管紊乱对疾病严重程度产生积极影响。肝硬化患者和肝纤维化小鼠的肝内皮细胞亚群会发生内皮-间充质转化。健康小鼠的肝内皮细胞在体外培养中对TGF-β1处理会转变为间充质表型。长期用BMP-7治疗的纤维化肝脏显示EndMT发生率较低、纤维化减少且血管结构改善。
