Gaça Marianna D A, Zhou Xiaoying, Issa Razao, Kiriella Kishanee, Iredale John P, Benyon R Christopher
Liver Research Group, University of Southampton Division of Infection, Inflammation and Repair, Southampton General Hospital, SO16 6YD, Southampton, UK.
Matrix Biol. 2003 May;22(3):229-39. doi: 10.1016/s0945-053x(03)00017-9.
During liver fibrosis hepatic stellate cells become activated, transforming into proliferative myofibroblastic cells expressing type I collagen and alpha-smooth muscle actin. They become the major producers of the fibrotic neomatrix in injured liver. This study examines if activated stellate cells are a committed phenotype, or whether they can become deactivated by extracellular matrix. Stellate cells isolated from normal rat liver proliferated and expressed mRNA for activation markers, alpha-smooth muscle actin, type I procollagen and tissue inhibitor of metalloproteinases-1 following 5-7 day culture on plastic, but culture on Matrigel suppressed proliferation and mRNA expression. Activated stellate cells were recovered from plastic by trypsinisation and replated onto plastic, type I collagen films or Matrigel. Cells replated on plastic and type I collagen films proliferated and remained morphologically myofibroblastic, expressing alpha-smooth muscle actin and type I procollagen. However, activated cells replated on Matrigel showed <30% of the proliferative rate of these cells, and this was associated with reduced cellular expression of proliferating cell nuclear antigen and phosphorylation of mitogen-activated protein kinase in response to serum. Activated HSC replated on Matrigel for 3-7 days progressively reduced their expression of mRNA for type I procollagen and alpha-smooth muscle actin and both became undetectable after 7 days. We conclude that basement membrane-like matrix induces deactivation of stellate cells. Deactivation represents an important potential mechanism mediating recovery from liver fibrosis in vivo where type I collagen is removed from the liver and stellate cells might re-acquire contact with their normal basement membrane-like pericellular matrix.
在肝纤维化过程中，肝星状细胞被激活，转变为增殖性肌成纤维细胞，表达I型胶原蛋白和α-平滑肌肌动蛋白。它们成为受损肝脏中纤维化新基质的主要产生者。本研究探讨激活的星状细胞是否是一种固定的表型，或者它们是否能被细胞外基质失活。从正常大鼠肝脏分离的星状细胞在塑料培养皿上培养5 - 7天后增殖并表达激活标志物、α-平滑肌肌动蛋白、I型前胶原和金属蛋白酶组织抑制剂-1的mRNA，但在基质胶上培养则抑制增殖和mRNA表达。通过胰蛋白酶消化从塑料培养皿上回收激活的星状细胞，再接种到塑料培养皿、I型胶原膜或基质胶上。重新接种到塑料培养皿和I型胶原膜上的细胞增殖并保持肌成纤维细胞形态，表达α-平滑肌肌动蛋白和I型前胶原。然而，重新接种到基质胶上的激活星状细胞的增殖率不到这些细胞的30%，这与细胞增殖细胞核抗原的表达降低以及丝裂原活化蛋白激酶对血清的磷酸化反应减少有关。重新接种到基质胶上3 - 7天的激活肝星状细胞逐渐降低其I型前胶原和α-平滑肌肌动蛋白的mRNA表达，7天后两者均无法检测到。我们得出结论，基底膜样基质可诱导星状细胞失活。失活代表了一种重要的潜在机制，介导体内肝纤维化的恢复，其中I型胶原从肝脏中清除，星状细胞可能重新与它们正常的基底膜样细胞周围基质接触。
