The let-7/Lin28 axis regulates activation of hepatic stellate cells in alcoholic liver injury
The let-7/Lin28 axis regulates activation of hepatic stellate cells in alcoholic liver injury
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DOI：
10.1074/jbc.m116.773291
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发表时间：
2017-07-07
影响因子：
4.8
通讯作者：
Meng, Fanyin
中科院分区：
文献类型：
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作者：
McDaniel, Kelly;Huang, Li;Meng, Fanyin
let-7/Lin 28轴与各种人类疾病和癌症发展中称为microRNA的关键细胞调节基因的调节相关。本研究评价了let-7/Lin 28轴在酒精性肝损伤中调节肝星状细胞间充质表型的作用。Weidentified乙醇喂养显著下调小鼠肝脏中let-7家族的几个成员，包括let-7a和let-7 b。同样，用脂多糖（LPS）和转化生长因子-β（TGF-β）处理人肝星状细胞（HSC）显著降低let-7a和let-7 b的表达。相反，let-7a和let-7 b的过表达抑制了LPS和TGF-β诱导的培养的人HSC的成肌纤维细胞活化，如被抑制的ACTA 2（α-肌动蛋白2）、COL 1A 1（胶原1A 1）、TIMP 1（TIMP金属肽酶抑制剂1）和FN 1（纤连蛋白1）所证明的;这支持了HSC活化受let-7控制的观点。生物信息学、双荧光素酶报告基因检测和Western blot分析的结合表明，Lin 28 B和高迁移率族AT-钩（HMGA 2）是let-7a和let-7 b的直接靶点。此外，Lin 28 B缺陷增加了let-7a/let-7 b的表达，并降低了酒精性肝损伤小鼠的HSC活化和肝纤维化。通过激光捕获显微切割从模型中分离的肝星状细胞中验证了Lin 28 B对let-7的反馈调节。let-7/Lin 28轴作为HSC活化的重要调节因子以及其上游调节剂和下游靶点的鉴定将为改变microRNA表达参与酒精性肝纤维化的发病机制和人类酒精性肝病的新治疗方法提供见解。
The let-7/Lin28 axis is associated with the regulation of key cellular regulatory genes known as microRNAs in various human disorders and cancer development. This study evaluated the role of the let-7/Lin28 axis in regulating a mesenchymal phenotype of hepatic stellate cells in alcoholic liver injury. Weidentified that ethanol feeding significantly down-regulated several members of the let-7 family in mouse liver, including let-7a and let-7b. Similarly, the treatment of human hepatic stellate cells (HSCs) with lipopolysaccharide (LPS) and transforming growth factor-beta (TGF-beta) significantly decreased the expressions of let-7a and let-7b. Conversely, overexpression of let-7a and let-7b suppressed the myofibroblastic activation of cultured human HSCs induced by LPS and TGF-beta, as evidenced by repressed ACTA2 (alpha-actin 2), COL1A1 (collagen 1A1), TIMP1 (TIMP metallopeptidase inhibitor 1), and FN1 (fibronectin 1); this supports the notion that HSC activation is controlled by let-7. A combination of bioinformatics, dual-luciferase reporter assay, and Western blot analysis revealed that Lin28B and highmobility group AT-hook (HMGA2) were the direct targets of let-7a and let-7b. Furthermore, Lin28B deficiency increased the expression of let-7a/let-7b as well as reduced HSC activation and liver fibrosis in mice with alcoholic liver injury. This feedback regulation of let-7 by Lin28B is verified in hepatic stellate cells isolated by laser capture microdissection from the model. The identification of the let-7/Lin28 axis as an important regulator of HSC activation as well as its upstream modulators and down-stream targets will provide insights into the involvement of altered microRNA expression in contributing to the pathogenesis of alcoholic liver fibrosis and novel therapeutic approaches for human alcoholic liver diseases.