Marra F, Romanelli R G, Giannini C, Failli P, Pastacaldi S, Arrighi M C, Pinzani M, Laffi G, Montalto P, Gentilini P
Istituto di Medicina Interna, Università di Firenze, Florence, Italy.
Hepatology. 1999 Jan;29(1):140-8. doi: 10.1002/hep.510290107.
Following liver injury, hepatic stellate cells (HSC) undergo proliferation and migrate into damaged areas in response to chemotactic factors. HSC have been shown to regulate leukocyte trafficking by secreting monocyte chemotactic protein-1 (MCP-1), a chemokine that recruits monocytes and lymphocytes. In this study, we explored whether MCP-1 exerts biological actions on HSC. HSC were isolated from normal human livers, cultured on plastic, and studied in their myofibroblast-like phenotype, and three different cells lines were used. Chemotaxis was measured in modified Boyden chambers. Phosphatidylinositol 3-kinase (PI 3-K) was assayed on phosphotyrosine immunoprecipitates. Exposure of HSC to MCP-1 stimulated migration of HSC in a dose-dependent fashion. Maximal stimulation was obtained with 250 ng/mL MCP-1, which resulted in a 3- to 4-fold stimulation of cell migration. Checkerboard analysis showed that the increase in cell migration was almost completely a result of chemotaxis rather than chemokinesis. In contrast, in quiescent HSC, MCP-1 did not exert any effect on cell migration. In leukocytes, MCP-1 activates the pertussis toxin-sensitive CCR2 receptor. However, transcripts for CCR2 could not be shown in HSC, and pertussis toxin only modestly inhibited MCP-1-induced migration. Exposure of HSC to MCP-1 was associated with an increase in cytosolic calcium concentration, PI 3-K activity, protein tyrosine phosphorylation. Blocking calcium influx or pretreatment of HSC with the PI 3-K inhibitor wortmannin markedly reduced cell migration. This study shows, for the first time, a potential direct profibrogenic action of MCP-1 via HSC chemotaxis. MCP-1-dependent signals in these cells are not transduced by CCR2 and may be mediated by alternative chemokine receptors. (HEPATOLOGY 1999;29:140-148.)
肝损伤后，肝星状细胞（HSC）会发生增殖，并在趋化因子的作用下迁移至受损区域。研究表明，HSC可通过分泌单核细胞趋化蛋白-1（MCP-1）来调节白细胞的迁移，MCP-1是一种可募集单核细胞和淋巴细胞的趋化因子。在本研究中，我们探讨了MCP-1是否对HSC具有生物学作用。从正常人类肝脏中分离出HSC，将其培养于塑料培养皿上，并以其肌成纤维细胞样表型进行研究，共使用了三种不同的细胞系。在改良的Boyden小室中检测趋化性。在磷酸酪氨酸免疫沉淀物上检测磷脂酰肌醇3激酶（PI 3-K）。HSC暴露于MCP-1后，以剂量依赖性方式刺激了HSC的迁移。250 ng/mL的MCP-1可获得最大刺激效果，使细胞迁移增加3至4倍。棋盘分析表明，细胞迁移的增加几乎完全是趋化作用而非趋化运动的结果。相比之下，在静止的HSC中，MCP-1对细胞迁移没有任何影响。在白细胞中，MCP-1可激活百日咳毒素敏感的CCR2受体。然而，在HSC中未检测到CCR2的转录本，百日咳毒素仅适度抑制MCP-1诱导的迁移。HSC暴露于MCP-1与胞质钙浓度、PI 3-K活性、蛋白酪氨酸磷酸化的增加有关。阻断钙内流或用PI 3-K抑制剂渥曼青霉素预处理HSC可显著降低细胞迁移。本研究首次表明，MCP-1通过HSC趋化作用具有潜在的直接促纤维化作用。这些细胞中依赖MCP-1的信号不是由CCR2转导的，可能由其他趋化因子受体介导。（《肝脏病学》1999年；29:140 - 148。）
