Research Project 1 - Hepatocellular Genetic Epidemiology of Fatty Liver Disease in Hispanics

项目总结 脂肪肝(FLD)是影响全球数百万人的重大公共卫生问题。两大 FLD的亚型包括酒精性FLD(AFLD)和非酒精性FLD(NAFLD)，尽管酒精的阈值 对细分的摄取是有争议的。FLD的定义是肝脏中过多的脂肪，可以导致更深层次的 脂肪性肝炎(SH)的一种疾病状态，其中肝脏炎症/损害可能反映在肝脏 纤维化症。自发性高血压可导致肝功能衰竭或肝细胞癌。主要的危险因素使个人容易患上 FLD的发生包括生物学因素(肥胖、胰岛素抵抗、2型糖尿病)人口统计学 特征(例如，性别、年龄和种族)、与行为和生活方式相关的变量(例如，酒精摄入量、 饮食行为和体力活动)以及其他环境因素(例如，肝炎等感染性因素 病毒、微生物组变异性、接触污染物/污染物/毒素)。拉美裔美国人受到了截然不同的影响 被世界上观察到的NAFLD患病率最高的NAFLD。 NAFLD的风险是由于遗传和环境因素及其相互作用的复杂组合，这些因素 大部分人的身份仍未确定。定量内表型(即与遗传相关的生物标志物 疾病风险)具有可加速发现与疾病相关的遗传致因因素的重要特性 并协助进行个人层面的风险评估。在这里，我们提出了一种新的深层细胞表型评估方法 诱导多能干细胞(IPSC)来源的肝细胞对实验性脂质过载攻击的反应 它模仿了饮食中的脂肪过量喂养。这项实验性的流行病学研究将使我们能够严格测试 用于基因与环境的相互作用(GEI)，以更好地了解NAFLD风险的病因/机制 并加强早期发现和阻止进展。具体地说，我们将识别新的IPSC衍生 墨西哥裔美国人中与NAFLD风险有关的肝细胞内表型，健康差异人群， 使用高吞吐量的多体方法。这项研究将使用现有的数据和900个细胞生物样本 我们的纵向墨西哥裔美国人家庭研究(MAFS)的参与者，他们已经被广泛表型 (包括肝脏核磁共振)和遗传学特征。我们的具体目标包括：1)发现新的肝细胞 全基因组RNA定量测序和功能评估对NAFLD风险的细胞内表型研究 在400名受试者中发现来自现有IPSCs的肝细胞；(2)发现多变量肝细胞 使用单细胞测序的转录一致性内表型；以及(3)确认最高 用另外500名MAFS受试者的MRI肝脏脂肪测量对NAFLD内表型进行排名 来自同一个家族。 非酒精性脂肪性肝病(NAFLD)是慢性肝病最常见的病因之一，它 对少数群体的影响是不同的，拉美裔是高危人群之一。通过识别 通过基因决定的细胞内表型，我们希望加快识别潜在的致病基因 在NAFLD风险和识别NAFLD遗传风险的非侵入性早期生物标记物方面。

PROJECT SUMMARY Fatty liver disease (FLD) is a major public health issue that affects millions of people worldwide. The two major subtypes of FLD include alcoholic FLD (AFLD) and nonalcoholic FLD (NAFLD) although the threshold of alcohol intake for subdivision is controversial. FLD is defined by excess fat in the liver and can lead to a more profound disease state of steatohepatitis (SH) in which there is liver inflammation/damage that may be reflected in hepatic fibrosis. SH can lead to liver failure or hepatocellular carcinoma. Major risk factors predisposing individuals to the development of FLD include biological factors (obesity, insulin resistance, type 2 diabetes) demographic characteristics (e.g., sex, age and ethnicity), behavioral and lifestyle-related variables (e.g., alcohol intake, dietary behavior and physical activity), and other environmental factors (e.g., infectious agents such as hepatitis viruses, microbiome variability, exposure to pollutants/contaminants/toxins). Hispanics are disparately impacted by NAFLD with the highest observed prevalence of NAFLD in the world. Risk for NAFLD is due to a complex mixture of genetic and environmental factors and their interactions that are still largely unidentified. Quantitative endophenotypes (i.e., biomarkers that are genetically correlated with disease risk) have important properties that can speed the discovery of disease-related genetic causal factors and aid in individual-level risk estimation. Here we propose a novel deep cellular phenotyping assessment of induced pluripotent stem cell (iPSC)-derived hepatocyte response to experimental lipid overload challenge, which mimics dietary lipid overfeeding. This experimental epidemiological study will allow us to rigorously test for genotype-by-environment interactions (GEI) to better understand the etiology/mechanisms of NAFLD risk and to enhance early detection and halt progression. Specifically, we will identify novel iPSC-derived hepatocellular endophenotypes involved in NAFLD risk in Mexican Americans, a health disparity population, using a high-throughput multiomic approach. The study will use existing data and cellular biosamples from 900 participants in our longitudinal Mexican American Family Study (MAFS), who have been extensively phenotyped (including liver MRI) and genetically characterized. Our specific aims include: 1) discovery of novel hepatocellular cellular endophenotypes for NAFLD risk by quantitative genome-wide RNA sequencing and functional evaluation of hepatocytes derived from existing iPSCs in 400 subjects; (2) discovery of multivariate hepatocellular transcriptional coherence endophenotypes using single-cell sequencing; and (3) confirmation of the highest ranking NAFLD endophenotypes using MRI-derived liver fat measures from an additional 500 MAFS subjects from the same families. Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease and it disparately affects minority populations, with Hispanics being one of the highest at-risk populations. By identifying genetically determined cellular endophenotypes, we hope to speed the identification of potential causal genes in NAFLD risk and for identifying non-invasive early biomarkers of genetic risk for NAFLD.