Hepatic stellate cell proliferation is an early platelet-derived growth factor-mediated cellular event in rat cholestatic liver injury
Hepatic stellate cell proliferation is an early platelet-derived growth factor-mediated cellular event in rat cholestatic liver injury
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DOI：
10.1038/labinvest.3780384
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发表时间：
2001-12-01
影响因子：
5
通讯作者：
Housset, C
中科院分区：
文献类型：
--
作者：
Kinnman, N;Goria, O;Housset, C
肝损伤后，肝星状细胞（HSC）经历一种称为“活化”的多向反应，这种反应也发生在培养模型中，最终导致HSC转化为表达平滑肌a-肌动蛋白（a- sma）的肌成纤维细胞。原代培养中HSC增殖的开始与血小板衍生生长因子受体- β (pdgfr - β)表达的诱导一致，而血小板衍生生长因子（PDGF）是培养激活HSC最有效的丝裂原。然而，在完整的肝脏中，HSC增殖所需的机制和激活阶段仍然不确定。在本研究中，我们分析了HSC对大鼠胆汁淤积性肝损伤的增殖反应以及PDGF在该反应中的作用。在胆管结扎（BDL）或假手术后不同时间点分离含维生素a的纯HSC，并采用流式细胞术进行分析。通过BrdU掺入确定，HSC增殖的诱导发生在24至48小时之间，并在BDL后48小时达到平台期。流式细胞术和免疫印迹分析表明，HSC的增殖诱导与表面pdgfr - β蛋白的上调一致，但高于α -SMA的上调。体外实验证明，PDGF受体酪氨酸激酶抑制剂STI571对PDGF- bb诱导的HSC增殖具有剂量依赖性抑制作用。每天腹腔注射STI571 （20 mg/kg）可使BrdU阳性分离的HSC减少60%，并使48小时胆管结扎大鼠肝组织切片上的desmin免疫反应性窦细胞数量减少60%。这些结果表明，胆汁淤积性肝损伤在主要由PDGF介导的HSC中引起早期增殖反应，并在HSC表型转化为肌成纤维细胞之前发生。
After liver injury, hepatic stellate cells (HSC) undergo a pleiotropic response termed "activation" that also occurs in culture models and ultimately leads to the conversion of HSC into myofibroblasts expressing smooth muscle a-actin (a-SMA). The onset of HSC proliferation in primary culture coincides with the induction of platelet-derived growth factor receptor-beta (PDGFR-beta) expression, while platelet-derived growth factor (PDGF) is the most potent mitogen for culture-activated HSC. Yet, the mechanisms and the stage of activation required for HSC proliferation in the intact liver are still uncertain. In the present study, we analyzed the proliferative response of HSC to rat cholestatic liver injury and the role of PDGF in this response. After in vivo incorporation of bromodeoxyuridine (BrdU), pure vitamin A-containing HSC were isolated at different time points after bile duct ligation (BDL) or sham operation and were analyzed by means of flow cytometry. The induction of HSC proliferation, as ascertained by BrdU incorporation, occurred between 24 and 48 hours and reached a plateau as soon as 48 hours after BDL. Flow cytometry and immunoblot analyses of HSC indicated that the induction of proliferation in HSC coincided with the up-regulation of PDGFR-beta protein on their surface but preceded that of alpha -SMA. A dose-dependent inhibition of PDGF-BB-induced HSC proliferation by STI571, a PDGF receptor tyrosine kinase inhibitor, was documented in vitro. Daily intraperitoneal injections of STI571 (20 mg/kg) caused a 60%, reduction in BrdU positive isolated HSC and in the amount of desmin-immunoreactive sinusoidal cells on liver tissue sections in 48-hour bile duct-ligated rats. These results indicate that cholestatic liver injury elicits an early proliferative response in HSC that is mainly mediated by PDGF, and which precedes HSC phenotypic conversion into myofibroblasts.