ECM1 Prevents Activation of Transforming Growth Factor β, Hepatic Stellate Cells, and Fibrogenesis in Mice
ECM1 Prevents Activation of Transforming Growth Factor β, Hepatic Stellate Cells, and Fibrogenesis in Mice
复制标题
ECM1 阻止小鼠转化生长因子 β、肝星状细胞和纤维形成的激活
DOI：
10.1053/j.gastro.2019.07.036
复制
发表时间：
2019-11-01
期刊：
影响因子：
29.4
通讯作者：
Sun, Bing
中科院分区：
文献类型：
--
作者：
Fan, Weiguo;Liu, Tianhui;Sun, Bing
背景与目的：TGFB（转化生长因子β）的激活通过激活肝星状细胞（hsc）促进肝纤维化，但TGFB激活的机制尚不清楚。我们研究了ECM1（细胞外基质蛋白1）在小鼠肝脏TGFB激活中的作用，ECM1与细胞外蛋白和结构蛋白相互作用。方法：我们对C57BL/6J小鼠（对照组）、ECM1敲除小鼠（ECM1- ko）和肝细胞特异性敲除EMC1 （ECM1(Delta hep)）的小鼠进行了研究。注射腺相关病毒载体后，ECM1或可溶性TGFB受体2在小鼠肝脏中表达。四氯化碳（CCl4）诱导肝纤维化。收集小鼠肝脏，进行组织学、免疫组织化学、原位杂交和免疫荧光分析。从小鼠肝脏中分离肝细胞和造血干细胞，用ECM1孵育；量化细胞因子的产生和报告基因的激活。采用免疫组织化学和原位杂交技术分析了病毒性或酒精性肝炎（不同纤维化阶段）患者和健康肝脏个体的肝组织。结果：ECM1-KO小鼠自发发生肝纤维化，并在2月龄时死亡，无明显的肝细胞损伤或炎症。在小鼠肝组织中，我们发现ECM1通过与av整合素相互作用来稳定细胞外基质沉积的TGFB，使其处于失活状态，从而阻止hsc的活化。在ccl4诱导肝纤维化患者和小鼠的肝组织中，我们发现ECM1水平与纤维化严重程度呈负相关。与对照组小鼠相比，CCl4诱导的ecm1hep小鼠肝纤维化加速。肝细胞在小鼠肝脏中产生最高水平的ECM1。肝脏中ECM1或可溶性TGFBR2的异位表达可阻止ECM1- ko小鼠的纤维化，延长其生存期。肝脏中ECM1的异位表达也降低了ccl4诱导的小鼠纤维化的严重程度。结论：肝细胞产生的ECM1可抑制TGFB的激活及其对hsc的激活，从而阻止小鼠肝脏纤维化的发生。提高肝脏ECM1水平的策略可能用于治疗纤维化。
BACKGROUND & AIMS: Activation of TGFB (transforming growth factor beta) promotes liver fibrosis by activating hepatic stellate cells (HSCs), but the mechanisms of TGFB activation are not clear. We investigated the role of ECM1 (extracellular matrix protein 1), which interacts with extracellular and structural proteins, in TGFB activation in mouse livers. METHODS: We performed studies with C57BL/6J mice (controls), ECM1-knockout (ECM1-KO) mice, and mice with hepatocyte- specific knockout of EMC1 (ECM1(Delta hep)). ECM1 or soluble TGFBR2 (TGFB receptor 2) were expressed in livers of mice after injection of an adeno-associated virus vector. Liver fibrosis was induced by carbon tetrachloride (CCl4) administration. Livers were collected from mice and analyzed by histology, immunohistochemistry, in situ hybridization, and immunofluorescence analyses. Hepatocytes and HSCs were isolated from livers of mice and incubated with ECM1; production of cytokines and activation of reporter genes were quantified. Liver tissues from patients with viral or alcohol-induced hepatitis (with different stages of fibrosis) and individuals with healthy livers were analyzed by immunohistochemistry and in situ hybridization. RESULTS: ECM1-KO mice spontaneously developed liver fibrosis and died by 2 months of age without significant hepatocyte damage or inflammation. In liver tissues of mice, we found that ECM1 stabilized extracellular matrix-deposited TGFB in its inactive form by interacting with av integrins to prevent activation of HSCs. In liver tissues from patients and in mice with CCl4-induced liver fibrosis, we found an inverse correlation between level of ECM1 and severity of fibrosis. CCl4- induced liver fibrosis was accelerated in ECM1Dhep mice compared with control mice. Hepatocytes produced the highest levels of ECM1 in livers of mice. Ectopic expression of ECM1 or soluble TGFBR2 in liver prevented fibrogenesis in ECM1-KO mice and prolonged their survival. Ectopic expression of ECM1 in liver also reduced the severity of CCl4-induced fibrosis in mice. CONCLUSIONS: ECM1, produced by hepatocytes, inhibits activation of TGFB and its activation of HSCs to prevent fibrogenesis in mouse liver. Strategies to increase levels of ECM1 in liver might be developed for treatment of fibrosis.