Hepatic Macrophages Express Melanoma Differentiation-Associated Gene 5 in Nonalcoholic Steatohepatitis
Hepatic Macrophages Express Melanoma Differentiation-Associated Gene 5 in Nonalcoholic Steatohepatitis
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DOI：
10.1007/s10753-021-01550-8
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发表时间：
2021-09-15
期刊：
影响因子：
5.1
通讯作者：
Imaizumi, Tadaatsu
中科院分区：
文献类型：
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作者：
Kawaguchi, Shogo;Sakuraba, Hirotake;Imaizumi, Tadaatsu
先天免疫系统的激活在非酒精性脂肪性肝炎（NASH）的发病机制中至关重要。在模式识别受体中，Toll样受体（TLR）深入参与NASH的发展以反映肝脏暴露于肠道驱动的内毒素是充分表征的。相反，尚未阐明视黄酸诱导基因-I（RIG-I）样受体（RLR）是否类似地涉及疾病进展。在本研究中，我们研究了黑色素瘤分化相关抗原5（MDA 5）的表达，已知是RLRs的成员，在饮食诱导的NASH小鼠模型。在胆碱缺乏l-氨基酸限定的高脂饮食（CDAHFD）后1、3和6周，从C57 BL/6 J小鼠收集肝组织，并通过蛋白质印迹、免疫荧光（IF）和实时定量PCR（qPCR）分析MDA 5的表达。Western blotting结果显示，MDA 5在3周和6周时表达增加。IF中MDA 5阳性细胞共表达F4/80和CD 11b，表明它们是活化的巨噬细胞，CDAHFD后1周开始出现。MDA 5 mRNA表达在1周时显著上调。此外，我们使用从11名非酒精性脂肪性肝病（NAFLD）患者中收集的肝活检标本进行IF，发现在11名患者中的8名中检测到MDA 5阳性巨噬细胞。在体外研究中，在小鼠骨髓源性巨噬细胞和THP-1细胞中，用脂多糖刺激后诱导MDA 5。我们的研究结果表明，MDA 5可能参与NASH的炎症反应。
The activation of innate immune system is essential for the pathogenesis of nonalcoholic steatohepatitis (NASH). Among pattern recognition receptors, it is well-characterized that toll-like receptors (TLRs) are deeply involved in the development of NASH to reflect exposure of the liver to gut-driven endotoxins. In contrast, it has not been elucidated whether retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) are similarly implicated in the disease progression. In the present study, we examined the expression of melanoma differentiation-associated antigen 5 (MDA5), known to be a member of RLRs, in a diet-induced murine model of NASH. The liver tissues were collected from C57BL/6 J mice at 1, 3, and 6 weeks after choline-deficient l-amino acid-defined high-fat diet (CDAHFD), and the expression of MDA5 was analyzed by western blotting, immunofluorescence (IF), and real-time quantitative PCR (qPCR). The results of western blotting showed that hepatic expression of MDA5 was increased at 3 and 6 weeks. In IF, MDA5positive cells co-expressed F4/80 and CD11b, indicating they were activated macrophages, and these cells began to appear at 1 week after CDAHFD. The mRNA expression of MDA5 was significantly upregulated at 1 week. Additionally, we performed IF using liver biopsy specimens collected from 11 patients with nonalcoholic fatty liver diseases (NAFLD), and found that MDA5-positive macrophages were detected in eight out of eleven patients. In an in vitro study, MDA5 was induced upon stimulation with lipopolysaccharide in murine bone marrow-derived macrophages and THP-1 cells. Our findings suggest that MDA5 may be involved in the inflammation of NASH.