Genomic and genetic determinants of the susceptibility to non-alcoholic fatty liver disease (NAFLD) and NAFLD-related liver cancer

研究表观基因组和基因组因素如何影响人类非酒精性脂肪性肝病（NAFLD）易感性的分子基础，使用人类NAFLD样本是可取的，但往往不切实际。相比之下，使用类似人类NAFLD发展的相关动物模型可能会大大克服人类研究的许多局限性，并为与NAFLD易感性和严重程度相关的病原学因素的分子后果提供重要线索。该机构间协议（IAA）将调查NAFLD相关肝损伤（包括非酒精性脂肪性肝炎（NASH），一种进行性NAFLD）的分子变化程度，以协助确定假定的分子标记物和/或靶标。我们假设：(a)个体表观基因组肝脏表型的状态是预先决定NAFLD易感性的一个基本因素；(b)评估遗传异质性小鼠群体的表观基因组肝脏表型将有助于确定NAFLD的分子易感性。为了验证这一假设，我们计划在协作杂交（CC）小鼠（一种遗传多样化的小鼠种群）中使用一种完善的饮食（“西方饮食”）诱导的NASH模型。我们将在遗传多样性的小鼠群体中确定对NAFLD相关肝损伤表现出最大易感性的个体小鼠，并确定表观遗传改变在NAFLD发病机制中的作用。我们还计划研究与NASH和NASH相关HCC发展相关的关键分子机制。为了实现这一目标，我们将给雄性和雌性CC小鼠品系（2只敏感和2只耐药）喂食长时间（60周）的高脂肪饮食，以研究与nash源性HCC发展相关的潜在病理生理过程。我们期望能够确定潜在的分子机制，并确定与NAFLD差异敏感性及其进展相关的途径，以推进NASH和NASH-纤维化阶段。这些研究将利用下一代测序、染色质免疫沉淀与DNA微阵列方法（Chip-on-chip）和定量RT-PCR来评估治疗和对照小鼠血浆、白细胞和肝脏中蛋白编码和非编码rna，特别是microrna的全基因组级表观基因组变化和表达。粪便微生物群与脂肪肝易感性的关系也正在进行分析。

Investigating the molecular basis of how epigenomic and genomic factors influence susceptibility to Nonalcoholic fatty liver disease (NAFLD) in humans using human NAFLD samples is desirable but frequently impractical. In contrast, using relevant animal models that resemble human NAFLD development may substantially overcome the many limitations of human studies and provide important clues regarding the molecular consequences of etiological factors linked to NAFLD susceptibility and severity. This Inter-Agency Agreement (IAA) will investigate the extent of molecular changes indicative of NAFLD-associated liver injury (including nonalcoholic steatohepatitis (NASH), a progressive form of NAFLD) to assist in identifying putative molecular markers and/or targets. We hypothesize that (a) the status of individual epigenomic hepatic phenotypes is a fundamental factor that predetermines susceptibility to NAFLD; and (b) an evaluation of epigenomic hepatic phenotypes in a genetically heterogeneous mouse population will assist in identifying molecular susceptibility to NAFLD. To test the hypothesis, we plan to use a well-established dietary- (“Western Diet”) induced model of NASH in Collaborative Cross (CC) mice, a genetically diverse population of mice. We will identify individual mice exhibiting the greatest susceptibility to NAFLD-associated liver injury in the genetically diverse population of mice and define the role of epigenetic alterations in the pathogenesis of NAFLD. We also plan to investigate the key molecular mechanisms associated with the development of NASH and NASH-associated HCC. To achieve this goal, we will feed male and female CC mouse strains (2 sensitive and 2 resistant) a high-fat diet for a prolonged time (60 weeks) to investigate the underlying pathophysiological processes associated with the development of NASH-derived HCC. We anticipate being able to define the underlying molecular mechanisms and identify pathways associated with differential sensitivity to NAFLD and its progression to advance NASH and NASH-fibrosis stages. These studies will utilize next generation sequencing, chromatin immunoprecipitation with DNA microarray methodology (Chip-on-chip) and quantitative RT-PCR to assess whole genome-scale epigenomic changes and expression of protein-coding and non-coding RNAs, especially microRNAs, in plasma, white blood cells, and livers of treated and control mice. Analysis of the relationship between fecal microbiota and fatty liver susceptibility is also being conducted.