Negligible Contribution of Bone Marrow-Derived Cells to Collagen Production During Hepatic Fibrogenesis in Mice
Negligible Contribution of Bone Marrow-Derived Cells to Collagen Production During Hepatic Fibrogenesis in Mice
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DOI：
10.1053/j.gastro.2009.07.006
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发表时间：
2009-10-01
期刊：
影响因子：
29.4
通讯作者：
Inagaki, Yutaka
中科院分区：
文献类型：
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作者：
Higashiyama, Reiichi;Moro, Tadashi;Inagaki, Yutaka
背景与目的：最近的研究报道，骨髓（BM）来源的细胞迁移到纤维化的肝组织表现出肌纤维母细胞样表型，并可能参与肝纤维化的进展。然而，它们对胶原蛋白产生的贡献尚未得到充分证实。我们通过使用2种机制上不同的肝纤维化模型，将其引入转基因胶原报告基因小鼠及其BM受体，重新审视了这个问题。方法：野生型小鼠的BM被从转基因动物获得的细胞替代，所述转基因动物携带与增强型绿色荧光蛋白（EGFP）或萤火虫荧光素酶（LUC）基因连接的α 2（I）胶原基因（COL 1A 2）的组织特异性增强子/启动子序列。通过反复注射四氯化碳或结扎胆总管将肝纤维化引入这些小鼠。通过共聚焦显微镜检查检测EGFP信号和肝匀浆的荧光素酶测定来评估COL 1A 2启动子的激活。研究结果：组织特异性COL 1A 2增强子/启动子在单次四氯化碳注射后或在塑料上原代培养期间在肝星状细胞中被激活。在两种肝纤维化模型中，在转基因COL 1A 2/EGFP小鼠的肝组织中观察到大量的EGFP阳性胶原表达细胞。相反，在COL 1A 2/EGFP受体的纤维化肝组织中检测到很少的EGFP阳性BM衍生的胶原产生细胞。来自COL 1A 2/LUC受体小鼠的肝组织的荧光素酶测定进一步表明，BM衍生的细胞响应于纤维化刺激产生很少的胶原。结论：通过使用一个特定的和敏感的实验系统，它专门检测BM衍生的胶原蛋白产生细胞，我们得出结论，在肝纤维化过程中的胶原蛋白产生的BM衍生细胞的作用出乎意料的有限。
BACKGROUND & AIMS: Recent studies have reported that bone marrow (BM)-derived cells migrating into fibrotic liver tissue exhibit a myofibroblast-like phenotype and may participate in the progression of liver fibrosis. However, their contribution to collagen production has not been fully verified yet. We revisited this issue by using 2 mechanistically distinct liver fibrosis models introduced into transgenic collagen reporter mice and their BM recipients. METHODS: BM of wild-type mice was replaced by cells obtained from transgenic animals harboring tissue-specific enhancer/promoter sequences of alpha 2(I) collagen gene (COL1A2) linked to enhanced green fluorescent protein (EGFP) or firefly luciferase (LUC) gene. Liver fibrosis was introduced into those mice by repeated carbon tetrachloride injections or ligation of the common bile duct. Activation of COL1A2 promoter was assessed by confocal microscopic examination detecting EGFP signals and luciferase assays of liver homogenates. RESULTS: The tissue-specific COL1A2 enhancer/promoter was activated in hepatic stellate cells following a single carbon tetrachloride injection or during primary culture on plastic. A large number of EGFP-positive collagen-expressing cells were observed in liver tissue of transgenic COL1A2/EGFP mice in both liver fibrosis models. in contrast, there were few EGFP-positive BM-derived collagen-producing cells detected in fibrotic liver tissue of COL1A2/EGFP recipients. Luciferase assays of liver tissues From COL1A2/LUC-recipient mice further indicated that BM-derived cells produced little collagen in response to fibrogenic stimuli. CONCLUSIONS: By using a specific and sensitive experimental system, which detects exclusively BM-derived collagen-producing cells, we conclude an unexpectedly limited role of BM-derived cells in collagen production during hepatic fibrogenesis.