Azar Fida, Courtet Kevin, Dekky Bassil, Bonnier Dominique, Dameron Olivier, Colige Alain, Legagneux Vincent, Théret Nathalie
University Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, Rennes, France.
University Rennes, CNRS, IRISA (Institut de recherche en informatique et système aléatoire, Rennes, France.
Liver Int. 2020 Aug;40(8):2021-2033. doi: 10.1111/liv.14476. Epub 2020 May 5.
BACKGROUND & AIMS: Activation of hepatic stellate cells (HSC) is a critical process involved in liver fibrosis. Several miRNAs are implicated in gene regulation during this process but their exact and respective contribution is still incompletely understood. Here we propose an integrative approach of miRNA-regulatory networks to predict new targets.
miRNA regulatory networks in activated HSCs were built using lists of validated miRNAs and the CyTargetLinker tool. The resulting graphs were filtered according to public transcriptomic data and the reduced graphs were analysed through GO annotation. A miRNA network regulating the expression of TIMP3 was further studied in human liver samples, isolated hepatic cells and mouse model of liver fibrosis.
Within the up-regulated miRNAs, we identified a subnetwork of five miRNAs (miR-21-5p, miR-222-3p, miR-221-3p miR-181b-5p and miR-17-5p) that target TIMP3. We demonstrated that TIMP3 expression is inversely associated with inflammatory activity and IL1-ß expression in vivo. We further showed that IL1-ß inhibits TIMP3 expression in HSC-derived LX-2 cells. Using data from The Cancer Genome Atlas (TCGA), we showed that, in hepatocellular carcinoma (HCC), TIMP3 expression is associated with survival (P < .001), while miR-221 (P < .05), miR-222 (P < .01) and miR-181b (P < .01) are markers for a poor prognosis.
Several miRNAs targeting TIMP3 are up-regulated in activated HSCs and down-regulation of TIMP3 expression is associated with inflammatory activity in liver fibrosis and poor prognosis in HCC. The regulatory network including specific miRNAs and TIMP3 is therefore central for the evolution of chronic liver disease.
肝星状细胞（HSC）的激活是肝纤维化过程中的一个关键环节。在此过程中，多种微小RNA（miRNA）参与基因调控，但其确切及各自的作用仍未完全明确。本文提出一种整合miRNA调控网络的方法来预测新靶点。
利用经过验证的miRNA列表和CyTargetLinker工具构建激活的HSC中的miRNA调控网络。根据公开的转录组数据对生成的图谱进行筛选，并通过基因本体（GO）注释对简化后的图谱进行分析。在人肝样本、分离的肝细胞和肝纤维化小鼠模型中，进一步研究调控金属蛋白酶组织抑制因子3（TIMP3）表达的miRNA网络。
在上调的miRNA中，我们鉴定出一个由5种miRNA（miR-21-5p、miR-222-3p、miR-221-3p、miR-181b-5p和miR-17-5p）组成的子网络，它们靶向TIMP3。我们证明，在体内TIMP3表达与炎症活性及白细胞介素1β（IL1-β）表达呈负相关。我们进一步表明，IL1-β抑制HSC来源的LX-2细胞中TIMP3的表达。利用来自癌症基因组图谱（TCGA）的数据，我们发现，在肝细胞癌（HCC）中，TIMP3表达与生存率相关（P <.001），而miR-221（P <.05）、miR-222（P <.01）和miR-181b（P <.01）是预后不良的标志物。
在激活的HSC中，几种靶向TIMP3的miRNA上调，TIMP3表达下调与肝纤维化中的炎症活性及HCC的不良预后相关。因此，包括特定miRNA和TIMP3的调控网络对慢性肝病的进展至关重要。
