Children's Health Research Institute, London, Ontario, Canada ; Children's Health Research Institute, Department of Paediatrics, London, Ontario, Canada.
Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, United States of America.
PLoS One. 2014 Jan 21;9(1):e84182. doi: 10.1371/journal.pone.0084182. eCollection 2014.
Gene expression is affected by modifications to histone core proteins within chromatin. Changes in these modifications, or epigenetic reprogramming, can dictate cell fate and promote susceptibility to disease. The goal of this study was to determine the extent of epigenetic reprogramming in response to chronic stress that occurs following ablation of MIST1 (Mist1(-/-) ), which is repressed in pancreatic disease. Chromatin immunoprecipitation for trimethylation of lysine residue 4 on histone 3 (H3K4Me3) in purified acinar cells from wild type and Mist1(-/-) mice was followed by Next Generation sequencing (ChIP-seq) or ChIP-qPCR. H3K4Me3-enriched genes were assessed for expression by qRT-PCR in pancreatic tissue before and after induction of cerulein-induced pancreatitis. While most of H3K4Me3-enrichment is restricted to transcriptional start sites, >25% of enrichment sites are found within, downstream or between annotated genes. Less than 10% of these sites were altered in Mist1(-/-) acini, with most changes in H3K4Me3 enrichment not reflecting altered gene expression. Ingenuity Pathway Analysis of genes differentially-enriched for H3K4Me3 revealed an association with pancreatitis and pancreatic ductal adenocarcinoma in Mist1(-/-) tissue. Most of these genes were not differentially expressed but several were readily induced by acute experimental pancreatitis, with significantly increased expression in Mist1(-/-) tissue relative to wild type mice. We suggest that the chronic cell stress observed in the absence of MIST1 results in epigenetic reprogramming of genes involved in promoting pancreatitis to a poised state, thereby increasing the sensitivity to events that promote disease.
基因表达受染色质中核心组蛋白的修饰影响。这些修饰的变化,或表观遗传重编程,可以决定细胞命运并促进疾病易感性。本研究的目的是确定在 MIST1 缺失(Mist1(-/-))后发生的慢性应激反应中表观遗传重编程的程度,MIST1 在胰腺疾病中受到抑制。从野生型和 Mist1(-/-) 小鼠的纯化腺泡细胞中进行组蛋白 3 赖氨酸残基 4 三甲基化(H3K4Me3)的染色质免疫沉淀,然后进行下一代测序(ChIP-seq)或 ChIP-qPCR。通过 qRT-PCR 在诱导 Cerulein 诱导的胰腺炎前后评估胰腺组织中 H3K4Me3 富集基因的表达。虽然大多数 H3K4Me3 富集都局限于转录起始位点,但 >25%的富集位点位于注释基因内部、下游或之间。在 Mist1(-/-) 腺泡中,不到 10%的这些位点发生改变,大多数 H3K4Me3 富集的变化并不反映基因表达的改变。对 H3K4Me3 差异富集基因进行的 Ingenuity 通路分析显示,它们与 Mist1(-/-) 组织中的胰腺炎和胰腺导管腺癌有关。大多数这些基因的表达没有差异,但有几个基因很容易被急性实验性胰腺炎诱导,并且在 Mist1(-/-) 组织中的表达明显高于野生型小鼠。我们认为,在缺乏 MIST1 的情况下观察到的慢性细胞应激导致参与促进胰腺炎的基因发生表观遗传重编程,从而增加了对促进疾病的事件的敏感性。