Molecular Mechanisms of TRIB1 Regulation of Hepatic Metabolism

TRIB1调节肝脏代谢的分子机制

• 批准号: 10660520
• 负责人: Robert Clayton Bauer
• 金额: $ 62.66万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10660520
• 关键词: 8q24; Address; Animal Model; Animals; Binding; Biological Assay; Biological Markers; Biology; CEBPA gene; Cardiometabolic Disease; Cell Line; Cholesterol; Complex; Consent; Coronary Arteriosclerosis; Cryoelectron Microscopy; DNA; Data; Data Set; Dyslipidemias; Enrollment; Enzymes; Family member; Fatty Liver; Gene Expression; Genes; Genetic; Genetically Modified Animals; Genome; Glycosylated hemoglobin A; Goals; Health; Hepatic; Hepatocyte; High Density Lipoprotein Cholesterol; Human; Human Genetics; Human Genome; In Vitro; Individual; Knock-out; Knowledge; LDL Cholesterol Lipoproteins; Ligation; Link; Lipids; Liver; Measurement; Mediating; Metabolic; Metabolic Diseases; Metabolic syndrome; Modeling; Molecular; Molecular Conformation; Mus; Mutation; Myeloid Cells; Pakistan; Participant; Pathway interactions; Phenotype; Physiology; Plasma; Population; Pre-Clinical Model; Process; Proteins; Proteomics; Regulation; Resources; Role; Safety; Specificity; Structure; Testing; Therapeutic; Thick; Treatment Efficacy; Triglycerides; Ubiquitin; Ubiquitination; Ultrasonography; Untranslated RNA; Variant; Very low density lipoprotein; Western World; Work; adiponectin; biobank; cardiometabolism; chronic liver disease; exome sequencing; experimental study; factor C; genetic association; genetic manipulation; genome resource; genome wide association study; genomic locus; hepatoma cell; human disease; in vivo; insight; lipid biosynthesis; lipid metabolism; liver function; liver metabolism; loss of function; metabolic phenotype; mortality; mouse model; mutant; non-alcoholic fatty liver disease; novel; overexpression; pleiotropism; preclinical study; somatic cell gene editing; structural biology; therapeutic evaluation; trait; transcription factor; transcriptome sequencing; translational potential; translational study; ubiquitin-protein ligase

PROJECT SUMMARY The 8q24 genomic locus, containing the gene Tribbles pseudokinase 1 (TRIB1) has been repeatedly linked via human genome-wide association study with multiple cardiometabolic parameters. This includes plasma total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, coronary artery disease (CAD), circulating liver enzymes and non-alcoholic fatty liver disease (NAFLD), circulating adiponectin, and HbA1c. This constellation of genetic associations is unique in the genome, and suggests that TRIB1 is a critical regulator of human metabolic health. Many of these traits are governed by hepatic metabolism, and knockout and overexpression studies in mouse livers have demonstrated that Trib1 is a critical regulator of hepatic lipid metabolism. Despite the genetic evidence supporting a role for this gene in human disease and early observations underscoring the importance of hepatic Trib1, mechanistic studies of this gene have lagged. Prior work in myeloid cells has established a model of TRIB1 function wherein it promotes the ubiquitination and degradation of the transcription factor C/EBPα, but the mechanisms governing this function have not been explored in hepatocytes. Additionally, while previous work demonstrated that hepatic overexpression of Trib1 reduces plasma lipids in mice, this therapeutic paradigm has not been tested in preclinical models of cardiometabolic disease. Finally, the direction of effect of TRIB1 in humans remains unknown, hampering the translational and therapeutic potential of this gene and related pathways. We present here preliminary data demonstrating that hepatic TRIB1 does promote COP1-dependent ubiquitination of the transcription factor C/EBPα, and this process requires a novel interaction with a different pseudokinase, STK40. Additionally, we have established multiple in vivo animal models to test the therapeutic potential of increased hepatic Trib1 activity in animal models of metabolic disease. Finally, we have utilized whole exome sequencing in a highly novel consanguineous population to identify predicted loss- of-function (pLoF) variants in TRIB1 that can help determine its function in humans. This experimental plan aims to address the above outlined knowledge gaps through accomplishment of the following specific aims: 1) To determine how hepatic TRIB1-mediated ubiquitination of target proteins is regulated by STK40; 2) To determine the therapeutic benefit of Trib1 overexpression in animal models of CAD and NAFLD, and the requirement for C/EBPα for such benefits; and 3) To determine the direction of effect and therapeutic potential for TRIB1 through the identification and metabolic phenotyping of subjects harboring TRIB1 pLoF variants. Completion of these aims will not only elucidate novel biology surrounding E3 ligases, pseudokinases, and the therapeutic potential of TRIB1, but also further our understanding of the mechanistic underpinnings of the myriad genetic associations with the TRIB1 gene in humans. Our ultimate goal is an in depth understanding of the functions of hepatic TRIB1 with the hope that this can inform therapeutic strategies targeting dyslipidemia and resultant CAD, steatosis and NAFLD, and metabolic syndrome in humans.

项目总结 含有TRIB1基因的8q24基因组基因座已通过 人类全基因组与多种心脏代谢参数的相关性研究。这包括血浆总数 胆固醇、低密度脂蛋白、高密度脂蛋白、甘油三酯、冠心病、循环肝脏 酶与非酒精性脂肪性肝病(NAFLD)、循环脂联素和糖化血红蛋白。这个星座 在基因组中是独一无二的，这表明TRIB1是人类 新陈代谢健康。这些特征中的许多是由肝脏代谢、基因敲除和过度表达决定的 对小鼠肝脏的研究表明，Trib1是肝脏脂代谢的关键调节因子。尽管 支持该基因在人类疾病中的作用的遗传学证据和早期观察强调 肝脏Trib1的重要性，对该基因的机制研究一直滞后。之前在髓系细胞方面的工作已经 建立了TRIB1促进转录泛素化和降解的功能模型 因子C/EBPα，但在肝细胞中调控这一功能的机制尚未被探索。另外， 虽然先前的工作表明，肝脏过表达Trib1可以降低小鼠的血脂，但这 治疗模式尚未在心脏代谢性疾病的临床前模型中进行测试。最后，方向是 TRIB1在人类中的作用尚不清楚，阻碍了它的翻译和治疗潜力 基因及其相关途径。我们在此提供的初步数据表明，肝脏TRIB1确实促进 依赖于COP1的转录因子C/eBPα的泛素化，这个过程需要一种新的相互作用 用一种不同的假激酶STK40。此外，我们还建立了多个活体动物模型来测试 代谢性疾病动物模型中肝脏Trib1活性升高的治疗潜力。最后，我们 已经在一个高度新颖的近亲群体中利用整个外显子组测序来识别预测的丢失- TRIB1中的非功能(PLoF)变体，可以帮助确定其在人类中的功能。这项试验计划旨在 通过实现以下具体目标来解决上述知识差距：1) 确定STK40如何调节肝脏TRIB1介导的靶蛋白泛素化；2)确定 Trib1在冠心病和非酒精性脂肪肝动物模型中的治疗效益及对 C/EBPα用于此类益处；以及3)确定TRIB1的作用方向和治疗潜力 携带TRIB1 pLoF变异体的受试者的鉴定和代谢表型。完成这些工作 AIMS不仅将阐明围绕E3连接酶、假激酶和治疗潜力的新生物学 也进一步加深了我们对无数遗传关联的机制基础的理解 在人类身上携带TRIB1基因。我们的最终目标是深入了解肝脏TRIB1的功能 希望这能为针对血脂异常和由此导致的CAD、脂肪变性和 非酒精性脂肪肝和人类的代谢综合征。