The Role of eIF4G1 and eIF4G2 in Translational Control of Adipogenesis and Obesity

eIF4G1 和 eIF4G2 在脂肪生成和肥胖转化控制中的作用

基本信息

批准号：
10464460
负责人：
Rachel Elizabeth Turn
金额：
$ 6.72万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10464460
关键词：
3T3-L1 Cells Address Adipocytes Adipose tissue Adult BODIPY Binding Binding Sites Biological Biological Assay Biological Models Cell Proliferation Cell physiology Cells Chronic Cilia Clustered Regularly Interspaced Short Palindromic Repeats Complex Cues Cyclic AMP Data Degenerative polyarthritis Deposition Development Diabetes Mellitus Disease Event Failure Fatty Acids Fatty acid glycerol esters Future G-Protein-Coupled Receptors Gene Targeting Generations Genes Genetic Models Genetic Transcription Goals Harvest Health Heart Diseases Histology Homologous Protein Hormones Human Hypertension Hypertrophy In Vitro Incidence Inflammation Inflammatory Insulin Insulin Resistance Kinetics Knock-out Knockout Mice Lead Life Ligands Link Lipids Maintenance Malignant Neoplasms Mammals Mediating Mesenchymal Stem Cells Messenger RNA Metabolic Metabolic Diseases Metabolism Modification Morbid Obesity Non-Insulin-Dependent Diabetes Mellitus Obese Mice Obesity Omega-3 Fatty Acids Pancreatitis Parkinson Disease Pathology Pathway interactions Patients Peptide Initiation Factors Population Prevalence Process Proteins Regulation Ribosomes Risk Role Signal Transduction Sorting - Cell Movement Source Stains Supplementation Surface Symptoms System Techniques Testing Therapeutic Time Tissues Training Transcript Translation Initiation Translations Triglycerides United States Weight Gain Work adipocyte differentiation base chemokine cytokine fatty liver disease genome wide screen genome-wide in vivo inhibitor insight lipid biosynthesis mouse genetics mouse model neurotransmission novel predictive test prevent programs receptor recruit reduce symptoms screening targeted treatment therapeutic development therapeutic target vision development

项目摘要

PROJECT SUMMARY Obesity, a disease caused by elevated fat mass, has increased in prevalence over the past few decades. Over 30% of the population suffers from obesity, and over time it can lead to increased incidence of life- threatening pathologies, including Type II Diabetes, heart disease, and cancer. Much study has been devoted to finding new treatments, which remain ineffective because 1) obesity is highly polygenic, and 2) they ameliorate symptoms rather than target the disease source. It is urgent to identify pathways disrupted in obesity to develop better therapeutics that more precisely treat the case-specific source of fat mass expansion. My lab contributed to this effort by performing a genome-wide screen for fat mass-regulating GPCRs and discovered FFAR4, a ciliary GPCR that binds ω-3 fatty acids to promote preadipocyte differentiation into new adipocytes (adipogenesis) instead of depositing lipids in existing tissue, causing inflammation (hypertrophy). This discovery is especially useful to human health because even though adipogenesis and hypertrophy both cause weight gain, hypertrophy is ultimately much more pernicious because the chronic inflammation leads to complications, including hypertension and diabetes. Therefore, understanding how FFAR4 drives preadipocyte differentiation may help us circumvent hypertrophic obesity and downstream pathology. The mechanism by which FFAR4 drives adipogenesis has yet to be elucidated. To do so, the Jackson lab performed the first genome-wide CRISPR knockout screen for FFAR4-pathway adipogenesis regulators using preadipocytes harvested at different time points post-differentiation. Our lab discovered that translation initiation factors eIF4G1 and eIF4G2, highly homologous proteins that compete for the same ribosomal binding site to drive transcript recruitment, have opposite effects on adipogenesis downstream of FFAR4: eIF4G2 was the strongest inhibitor and eIF4G1 was one of the strongest drivers of adipogenesis. I will test my central hypothesis that the switch from eIF4G2-dependent to eIF4G1-dependent translation (by degradation of eIF4G2 and activation of eIF4G1), downstream of FFAR4-induced cAMP signaling, drives fate change through converting to the translation of transcripts that specifically promote adipogenesis. I will use a combination of 3T3-L1 preadipocytes and mouse genetic models to gain mechanistic insight into eIF4G1/2 functions on a cellular and systemic level. In Aim 1, I will determine the mechanism of eIF4G1/2 function in preadipocyte differentiation in vitro. I will tease apart the pathway(s) through which eIF4G1 and eIF4G2 act by probing mechanism, tracking their kinetics in adipogenesis, determining if they are necessary/sufficient to drive adipogenesis, and identifying the transcripts they each regulate. In Aim 2, I will determine the role of eIF4G1/2 in fat expansion and metabolism in vivo using mouse model systems to see how eIF4G1 and eIF4G2 function relates to multicellular systems. Taken together, my work will pave the way for exploring the network of signaling events that drive adipogenesis downstream of the cilium and may pave the way for therapeutics targeting monogenic sources of obesity.

项目概要肥胖是一种由脂肪量增加引起的疾病，在过去几十年中患病率有所增加。超过 30% 的人口患有肥胖症，随着时间的推移，它会导致生活中的发病率增加—— 威胁性疾病，包括 II 型糖尿病、心脏病和癌症。寻找新的治疗方法，但这些治疗方法仍然无效，因为 1) 肥胖是高度多基因的，2) 它们可以改善肥胖迫切需要找出肥胖中被破坏的途径，而不是针对疾病的根源。更好的治疗方法可以更精确地治疗特定病例的脂肪量扩张来源。我的实验室通过对脂肪量调节 GPCR 进行全基因组筛选，为这项工作做出了贡献发现了 FFAR4，一种纤毛 GPCR，可结合 ω-3 脂肪酸，促进前脂肪细胞分化为新脂肪细胞脂肪细胞（脂肪生成）而不是在现有组织中沉积脂质，从而引起炎症（肥大）。这一发现对人类健康特别有用，因为尽管脂肪生成和肥大都导致体重增加，肥大最终危害更大，因为慢性炎症会导致因此，了解 FFAR4 如何驱动前脂肪细胞。分化可能有助于我们规避肥厚性肥胖和下游病理机制。哪种 FFAR4 驱动脂肪生成尚待阐明。为此，杰克逊实验室进行了首次研究。使用前脂肪细胞对 FFAR4 途径脂肪生成调节因子进行全基因组 CRISPR 敲除筛选我们的实验室发现翻译起始因子 eIF4G1 在分化后的不同时间点收获。和 eIF4G2，高度同源的蛋白质，竞争相同的核糖体结合位点来驱动转录募集，对 FFAR4 下游的脂肪生成产生相反的影响：eIF4G2 是最强的抑制剂 eIF4G1 是脂肪生成最强大的驱动因素之一，我将检验我的中心假设：这种开关。从 eIF4G2 依赖性翻译到 eIF4G1 依赖性翻译（通过 eIF4G2 降解和 eIF4G1 激活）， FFAR4 诱导的 cAMP 信号下游，通过转化为翻译来驱动命运改变我将使用 3T3-L1 前脂肪细胞和小鼠的组合来特异性促进脂肪生成。遗传模型，以深入了解 eIF4G1/2 在细胞和系统水平上的功能。将确定 eIF4G1/2 在体外前脂肪细胞分化中的功能机制。 eIF4G1 和 eIF4G2 通过探测机制起作用的途径，跟踪它们在脂肪生成中的动力学，确定它们是否有必要/足以驱动脂肪生成，并识别它们各自的转录本在目标 2 中，我将使用小鼠确定 eIF4G1/2 在体内脂肪膨胀和代谢中的作用。模型系统以了解 eIF4G1 和 eIF4G2 功能如何与多细胞系统相关。这项工作将为探索驱动下游脂肪生成的信号事件网络铺平道路。纤毛，可能为针对单基因肥胖源的治疗铺平道路。