Li Zhaodong, Dranoff Jonathan A, Chan Erick P, Uemura Masayuki, Sévigny Jean, Wells Rebecca G
Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Hepatology. 2007 Oct;46(4):1246-56. doi: 10.1002/hep.21792.
Myofibroblasts derived from portal fibroblasts are important fibrogenic cells in the early stages of biliary fibrosis. In contrast to hepatic stellate cells, portal fibroblasts have not been well studied in vitro, and little is known about their myofibroblastic differentiation. In this article we report the isolation and characterization of rat portal fibroblasts in culture. We demonstrate that primary portal fibroblasts undergo differentiation to alpha-smooth muscle actin-expressing myofibroblasts over 10-14 days. Marker analysis comparing portal fibroblasts to hepatic stellate cells demonstrated that these are distinct populations and that staining with elastin and desmin can differentiate between them. Portal fibroblasts expressed elastin at all stages in culture but never expressed desmin, whereas hepatic stellate cells consistently expressed desmin but never elastin. Immunostaining of rat liver tissue confirmed these results in vivo. Characterization of portal fibroblast differentiation in culture demonstrated that these cells required transforming growth factor-beta (TGF-beta): cells remained quiescent in the presence of a TGF-beta receptor kinase inhibitor, whereas exogenous TGF-beta1 enhanced portal fibroblast alpha-smooth muscle actin expression and stress fiber formation. In contrast, platelet-derived growth factor inhibited myofibroblastic differentiation. Portal fibroblasts were also dependent on mechanical tension for myofibroblastic differentiation, and cells cultured on polyacrylamide supports of variable stiffness demonstrated an increasingly myofibroblastic phenotype as stiffness increased.
Portal fibroblasts are morphologically and functionally distinct from hepatic stellate cells. Portal fibroblast myofibroblastic differentiation can be modeled in culture and requires both TGF-beta and mechanical tension.
源自门周成纤维细胞的肌成纤维细胞是胆管纤维化早期重要的促纤维化细胞。与肝星状细胞不同，门周成纤维细胞在体外尚未得到充分研究，对其肌成纤维细胞分化了解甚少。在本文中，我们报告了培养大鼠门周成纤维细胞的分离和特性。我们证明原代门周成纤维细胞在10 - 14天内会分化为表达α - 平滑肌肌动蛋白的肌成纤维细胞。将门周成纤维细胞与肝星状细胞进行标志物分析表明，它们是不同的细胞群体，用弹性蛋白和结蛋白染色可区分它们。门周成纤维细胞在培养的各个阶段都表达弹性蛋白，但从不表达结蛋白，而肝星状细胞始终表达结蛋白但从不表达弹性蛋白。大鼠肝脏组织的免疫染色在体内证实了这些结果。培养中门周成纤维细胞分化的特性表明，这些细胞需要转化生长因子 - β（TGF - β）：在存在TGF - β受体激酶抑制剂的情况下细胞保持静止，而外源性TGF - β1增强门周成纤维细胞α - 平滑肌肌动蛋白的表达和应力纤维的形成。相反，血小板衍生生长因子抑制肌成纤维细胞分化。门周成纤维细胞的肌成纤维细胞分化也依赖于机械张力，在不同硬度的聚丙烯酰胺支持物上培养的细胞随着硬度增加表现出越来越明显的肌成纤维细胞表型。
门周成纤维细胞在形态和功能上与肝星状细胞不同。门周成纤维细胞的肌成纤维细胞分化可以在培养中模拟，并且需要TGF - β和机械张力。
