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

使用人类NAFLD样本调查表观基因组和基因组因素如何影响人类对非酒精性脂肪性肝病（NAFLD）的易感性的分子基础是可取的，但通常是不切实际的。相比之下，使用类似于人类NAFLD发展的相关动物模型可以基本上克服人类研究的许多局限性，并提供有关与NAFLD易感性和严重性相关的病因因素的分子后果的重要线索。本机构间协议（IAA）将研究指示NAFLD相关肝损伤（包括非酒精性脂肪性肝炎（NASH），NAFLD的一种进行性形式）的分子变化程度，以帮助确定推定的分子标志物和/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易感性的基本因素;（B）在遗传异质性小鼠群体中评价表观基因组肝脏表型将有助于鉴定NAFLD的分子易感性。为了检验该假设，我们计划在协作杂交（CC）小鼠（一种遗传多样性小鼠群体）中使用完善的饮食（“西方饮食”）诱导的NASH模型。我们将在遗传多样的小鼠群体中鉴定出对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，我们将长时间（60周）喂食雄性和雌性CC小鼠品系（2只敏感和2只抗性）高脂肪饮食，以研究与NASH衍生的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的不同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、染色质免疫沉淀和DNA微阵列方法（芯片上芯片）以及定量RT-PCR来评估处理和对照小鼠的血浆、白色血细胞和肝脏中的全基因组规模表观基因组变化以及蛋白质编码和非编码RNA（尤其是microRNA）的表达。粪便微生物群与脂肪肝易感性之间的关系也在进行分析。

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.