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

• 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
• 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

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.

项目摘要 肥胖是由脂肪质量升高引起的疾病，在过去的几十年中的患病率增加了。 超过30％的人口患有肥胖症，随着时间的流逝，这可能导致生活发生率增加 - 威胁性病理，包括II型糖尿病，心脏病和癌症。很多研究已经专门 寻找新的治疗方法，因为1）肥胖是高度多基因的，2）它们可以改善 症状而不是针对疾病来源。迫切需要确定肥胖中破坏的途径以发展 更好的治疗方法，更精确地处理特定病例的脂肪质量扩张来源。 我的实验室通过对全基因组进行脂肪质量调节的GPCR和 发现的FFAR4是一种结合ω-3脂肪酸的睫状GPCR 脂肪细胞（脂肪生成），而不是沉积在现有组织中的脂质，引起感染（肥大）。 这一发现对人类健康特别有用，因为即使掺杂和肥大都 导致体重增加，肥大最终更加有害，因为慢性炎症会导致 并发症，包括高血压和糖尿病。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大肥胖和下游病理。机制 FFAR4驱动脂肪形成尚未阐明。为此，杰克逊实验室表演了第一个 FFAR4-Pathway脂肪形成调节剂的全基因组CRISPR敲除屏幕使用前脂肪细胞 分化后在不同时间点收获。我们的实验室发现翻译计划因素eif4g1 和EIF4G2，高度同源蛋白，竞争相同的核糖体结合位点驱动转录本 招募对FFAR4：EIF4G2下游的脂肪形成有相反的影响是强抑制剂 EIF4G1是脂肪生成的强大驱动因素之一。我将测试我的中心假设 从依赖EIF4G2到EIF4G1依赖性翻译（通过EIF4G2的降解和EIF4G1的激活）， FFAR4引起的营地信号的下游，通过转换为翻译来驱动命运变化 专门促进脂肪形成的转录本。我将使用3T3-L1前脂肪细胞和鼠标的组合 遗传模型可以在细胞和全身水平上获得对EIF4G1/2功能的机械洞察力。在AIM 1中，我 将确定体外前脂肪细胞分化中EIF4G1/2功能的机制。我会教分开 通过探测机制，跟踪其在脂肪形成中的动力学，EIF4G1和EIF4G2通过的途径， 确定它们是否需要/足以驱动脂肪形成，并确定它们每个的成绩单 调节。在AIM 2中，我将使用鼠标确定EIF4G1/2在体内脂肪膨胀和代谢中的作用 模型系统以查看EIF4G1和EIF4G2功能与多细胞系统的关系。总之，我 工作将为探索信号事件的网络铺平道路 纤毛和可能为瞄准肥胖单基因来源的治疗铺平道路。