Bulk_RNA_HepG2

Chronic liver disease is associated with metabolic dysregulation, liver failure and hepatocellular carcinoma. We analyzed somatic mutations from 1202 genomes across 32 liver samples, including normal controls, alcohol-related and non-alcoholic fatty liver disease. Five of 27 patients with liver disease carried hotspot driver mutations in FOXO1, the major transcription factor downstream of insulin signaling. FOXO1 mutations were independently acquired by up to 5 distinct clones within the same patient’s sample, and impaired insulin-mediated nuclear export of FOXO1. GPAM, which produces storage triacylglycerol from dietary calories, also had significant excess of mutations, similarly exhibiting convergent evolution within biopsies. Telomeres were shorter in diseased than normal liver, with attrition more pronounced in larger clones. Multiple independent acquisitions of drivers within one small liver sample imply that such mutations could affect hundreds of grams of tissue across the whole organ, potentially contributing to systemic metabolic dysfunction. The downstream consequences of the observed driver mutations will be assessed using RNA-Seq experiments in the HepG2 cell line.

慢性肝病与代谢失调、肝衰竭及肝细胞癌（hepatocellular carcinoma）密切相关。本研究对涵盖正常对照、酒精相关性及非酒精性脂肪性肝病（non-alcoholic fatty liver disease）的32份肝脏样本的1202个基因组的体细胞突变进行了分析。27例肝病患者中，有5例携带FOXO1热点驱动突变——FOXO1是胰岛素信号通路下游的核心转录因子（transcription factor）。FOXO1突变可由同一患者样本内至多5个不同的克隆独立获得，且会损害胰岛素介导的FOXO1核输出功能。负责将膳食热量合成为储存型三酰甘油的GPAM基因同样存在显著的突变富集，在活检样本中亦表现出趋同进化特征。病变肝脏的端粒较正常肝脏更短，且较大克隆的端粒损耗更为显著。在一小块肝脏样本中即可存在多起独立的驱动突变获取事件，这提示此类突变可能累及全器官内数百克的组织，或潜在参与全身性代谢功能紊乱的发生。本研究中观测到的驱动突变的下游效应，将通过在HepG2细胞系中开展的RNA测序（RNA-Seq）实验进行评估。