Children's Hospital of Philadelphia, Philadelphia, PA, USA.
Hepatology. 2011 May;53(5):1685-95. doi: 10.1002/hep.24206.
Whether or not cholangiocytes or their hepatic progenitors undergo an epithelial-to-mesenchymal transition (EMT) to become matrix-producing myofibroblasts during biliary fibrosis is a significant ongoing controversy. To assess whether EMT is active during biliary fibrosis, we used Alfp-Cre × Rosa26-YFP mice, in which the epithelial cells of the liver (hepatocytes, cholangiocytes, and their bipotential progenitors) are heritably labeled at high efficiency with yellow fluorescent protein (YFP). Primary cholangiocytes isolated from our reporter strain were able to undergo EMT in vitro when treated with transforming growth factor-β1 alone or in combination with tumor necrosis factor-α, as indicated by adoption of fibroblastoid morphology, intracellular relocalization of E-cadherin, and expression of α-smooth muscle actin (α-SMA). To determine whether EMT occurs in vivo, we induced liver fibrosis in Alfp-Cre × Rosa26-YFP mice using the bile duct ligation (BDL) (2, 4, and 8 weeks), carbon tetrachloride (CCl(4) ) (3 weeks), and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC; 2 and 3 weeks) models. In no case did we find evidence of colocalization of YFP with the mesenchymal markers S100A4, vimentin, α-SMA, or procollagen 1α2, although these proteins were abundant in the peribiliary regions.
Hepatocytes and cholangiocytes do not undergo EMT in murine models of hepatic fibrosis.
在胆管纤维化过程中，胆管细胞或其肝前体细胞是否经历上皮-间充质转化（EMT）成为产生基质的肌成纤维细胞，这是一个持续存在的争议。为了评估 EMT 在胆管纤维化过程中是否活跃，我们使用了 Alfp-Cre × Rosa26-YFP 小鼠，其中肝脏的上皮细胞（肝细胞、胆管细胞及其双潜能前体细胞）以高效率被遗传标记为黄色荧光蛋白（YFP）。从我们的报告株中分离的原代胆管细胞在单独或联合使用转化生长因子-β1 和肿瘤坏死因子-α时，能够在体外经历 EMT，表现为成纤维细胞样形态、E-钙黏蛋白的细胞内重定位以及α-平滑肌肌动蛋白（α-SMA）的表达。为了确定 EMT 是否在体内发生，我们使用胆管结扎（BDL）（2、4 和 8 周）、四氯化碳（CCl4）（3 周）和 3,5-二乙氧基羰基-1,4-二氢吡啶（DDC；2 和 3 周）模型在 Alfp-Cre × Rosa26-YFP 小鼠中诱导肝纤维化。在任何情况下，我们都没有发现 YFP 与间充质标志物 S100A4、波形蛋白、α-SMA 或前胶原 1α2 共定位的证据，尽管这些蛋白质在胆管周围区域丰富存在。
在肝纤维化的小鼠模型中，肝细胞和胆管细胞不经历 EMT。
