Hepatic stellate cell transdifferentiation involves genome-wide remodeling of the DNA methylation landscape.
Hepatic stellate cell transdifferentiation involves genome-wide remodeling of the DNA methylation landscape.
复制标题
肝星状细胞转差涉及DNA甲基化景观的全基因组重塑。
DOI：
10.1016/j.jhep.2015.11.024
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发表时间：
2016-03
影响因子：
25.7
通讯作者：
Mann J
中科院分区：
文献类型：
--
作者：
Page A;Paoli P;Moran Salvador E;White S;French J;Mann J
DNA甲基化是一种表观遗传标记，是转录抑制的既定调节因子，在肝纤维化中起着重要作用。目前，关于DNA甲基化如何控制肝星状细胞(HSC)的表型的知识很少，HSC是导致肝纤维化发生和发展的关键细胞类型。此外，最近发现DNA羟甲基化参与转录激活，其模式在人类疾病中经常改变。本研究的目的是探讨DNA甲基化/羟甲基化在肝纤维化中的作用。在一系列动物肝纤维化模型和人类肝病中，用狭缝印迹法检测5-MC和5-HMC的水平。用qRT-PCR和Western blotting检测Tet和DNMT酶的表达水平。用亚硫酸氢盐还原测序法检测静止和活体激活的大鼠肝星状细胞的5-MC和5-HMC模式。我们展示了伴随着肝纤维化和HSC转分化的5-MC和5-HMC及其调节酶的整体改变。利用RRBS，我们显示了静止和活体激活的大鼠HSC中甲基化模式改变的确切基因组位置。此外，我们还证明，DNMT3a表达的减少会导致活化的HSC中促纤维化表型的减弱。我们的数据表明DNA甲基化/羟甲基化是HSC激活从而导致纤维化的关键步骤。HSC激活过程中DNA甲基化的变化可能为支持纤维化发生的分子事件带来新的见解，并可能为疾病进展提供生物标记物以及潜在的新药靶点。
DNA methylation is an epigenetic mark that is an established regulator of transcriptional repression with an important role in liver fibrosis. Currently, there is very little knowledge available as to how DNA methylation controls the phenotype of hepatic stellate cell (HSC), the key cell type responsible for onset and progression of liver fibrosis. Moreover, recently discovered DNA hydroxymethylation is involved in transcriptional activation and its patterns are often altered in human diseases. The aim of this study is to investigate the role of DNA methylation/hydroxymethylation in liver fibrosis. Levels of 5-mC and 5-hmC were assessed by slot blot in a range of animal liver fibrosis models and human liver diseases. Expression levels of TET and DNMT enzymes were measured by qRT-PCR and western blotting. Reduced representation bisulfite sequencing method was used to examine 5-mC and 5-hmC patterns in quiescent and in vivo activated rat HSC. We demonstrate global alteration in 5-mC and 5-hmC and their regulatory enzymes that accompany liver fibrosis and HSC transdifferentiation. Using RRBS, we show exact genomic positions of changed methylation patterns in quiescent and in vivo activated rat HSC. In addition, we demonstrate that reduction in DNMT3a expression leads to attenuation of pro-fibrogenic phenotype in activated HSC. Our data suggest that DNA methylation/hydroxymethylation is a crucial step in HSC activation and therefore fibrogenesis. Changes in DNA methylation during HSC activation may bring new insights into the molecular events underpinning fibrogenesis and may provide biomarkers for disease progression as well as potential new drug targets.