Regulation of metabolism and diabetes mellitus by tristetraprolin

三四脯氨酸对代谢和糖尿病的调节

• 批准号: 8835820
• 负责人: Konrad Teodor Sawicki
• 金额: $ 3.6万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-05 至 2018-09-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8835820
• 关键词: 3' Untranslated Regions; Affect; Age; Arthritis; Binding; Biological Process; Birth; Blood Glucose; C57BL/6 Mouse; Cachexia; Clinical Research; Country; Development; Diabetes Mellitus; Diet; Disease Progression; Down-Regulation; Environment; Enzymes; Fatty Acids; Fatty acid glycerol esters; Gene Expression; Glucose; Goals; Hepatic; Hepatocyte; Histology; Homeostasis; Homologous Gene; Human; Indium; Inflammation; Inflammatory; Insulin; Insulin Resistance; Investigation; Iron; Knock-out; Knockout Mice; Knowledge; Lead; Link; Lipids; Liver; Measures; Mediating; Messenger RNA; Metabolic; Metabolic Pathway; Metabolic syndrome; Metabolism; Molecular; Morbidity - disease rate; Mus; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Oxygen Consumption; PPAR alpha; Patients; Peroxisome Proliferator-Activated Receptors; Phenotype; Play; Population; Prevalence; Process; Protein Binding; Proteins; Pyruvate; RNA Sequences; Regulation; Role; Severities; Syndrome; TIS11 protein; TNF gene; TNFRSF1A gene; Testing; Tumor Necrosis Factor Receptor; Tumor Necrosis Factor-alpha; United States; Up-Regulation; Yeasts; Zinc Fingers; blood glucose regulation; diabetes mellitus therapy; diabetic; fatty acid metabolism; fatty acid oxidation; feeding; glucose metabolism; glucose production; glucose uptake; in vivo; insulin sensitivity; lipid metabolism; liver metabolism; mortality; novel; novel therapeutics; oxidation; protective effect; public health relevance; pyruvate dehydrogenase kinase 4; receptor; research study; response; treatment strategy; uptake

DESCRIPTION (provided by applicant): Diabetes mellitus (DM) is a major cause of morbidity and mortality in the developed world, but the molecular mechanisms that lead to the development of DM are not well understood. Tristetraprolin (TTP) is a tandem zinc finger protein that binds to AU-rich elements in the 3'-untranslated region (3'-UTR) of target mRNA molecules, and promotes their degradation. TTP has been extensively studied in the field of inflammation, where it has been shown to bind to and degrade tumor necrosis factor ? (TNF??) mRNA. Our recent results suggest that TTP mRNA and protein levels are reduced in diabetic murine livers, and that TTP knockdown (KD) in hepatocytes increases the mRNA levels of peroxisome proliferator-activated receptor alpha (PPAR??), a major regulator of lipid metabolism, and pyruvate dehydrogenase kinase 4 (PDK4), a negative regulator of glucose utilization. Because TTP KO mice develop a lethal inflammatory phenotype shortly after birth due to elevated circulating levels of TNF??, we have obtained mice with simultaneous systemic knockout (KO) of TTP and TNF?? receptors (TNFR1/2) which lack TTP-dependent inflammation. My central hypothesis is that TTP mediates its effects on hepatic lipid metabolism and glucose utilization by modulating the levels of PPAR?? and PDK4, respectively, and that TTP protects against the development of DM through its metabolic effects. In Aim 1, I hypothesize that TTP KD mediates changes in lipid homeostasis through up regulation of PPAR??. I will isolate primary hepatocytes from mice with or without TTP deletion and determine the effects of TTP on lipid metabolism by measuring changes in lipid uptake, lipid content, beta- oxidation activity, and metabolic gene expression by RNA sequencing. All experiments will be repeated in the setting of TTP KO/PPAR?? KD. I will also determine whether TTP directly regulates PPAR?? by performing deletion studies of the 3'-UTR AREs within PPAR??. In Aim 2, I hypothesize that TTP KD mediates changes in glucose homeostasis through up regulation of PDK4. I will isolate primary hepatocytes from mice with or without TTP deletion and determine the effects of TTP on glucose metabolism by measuring changes in glucose uptake, glucose production, glucose oxidation, and gluconeogenic/glycolytic gene expression by RNA sequencing. All experiments will be repeated in the setting of TTP KO/PDK4 KD. I will also determine whether TTP directly regulates PDK4 by performing deletion studies of the 3'-UTR AREs within PDK4. Finally, in Aim 3, I hypothesize that TTP mediates protective effects against the development of type II diabetes mellitus. I will subject TTP/TNFR1/2 KO and TNFR1/2 KO (control) mice to high-fat diet and assess the progression of diabetes in these mice in terms of blood glucose and insulin levels. These lines of investigation promise to advance our knowledge of the role of TTP in diabetes, and may potentially lead to the development of novel diabetic therapies.

描述（由申请人提供）：糖尿病（DM）是发达国家发病和死亡的主要原因，但导致 DM 发展的分子机制尚不清楚。 Tristetraprolin (TTP) 是一种串联锌指蛋白，可与靶 mRNA 分子 3'-非翻译区 (3'-UTR) 中富含 AU 的元件结合，并促进其降解。 TTP 在炎症领域得到了广泛的研究，已被证明可以结合并降解肿瘤坏死因子？ (TNF??) mRNA。我们最近的研究结果表明，糖尿病小鼠肝脏中的 TTP mRNA 和蛋白质水平降低，肝细胞中的 TTP 敲低 (KD) 增加了过氧化物酶体增殖物激活受体 α (PPAR??)（脂质代谢的主要调节因子）和丙酮酸脱氢酶激酶 4 (PDK4)（脂质代谢的负调节因子）的 mRNA 水平。 葡萄糖利用率。由于 TTP KO 小鼠在出生后不久由于 TNFα 循环水平升高而形成致命的炎症表型，因此我们获得了 TTP 和 TNFα 同时全身性敲除 (KO) 的小鼠。受体 (TNFR1/2)，缺乏 TTP 依赖性炎症。我的中心假设是 TTP 通过调节 PPAR 水平来介导其对肝脏脂质代谢和葡萄糖利用的影响？和 PDK4，TTP 通过其代谢作用防止 DM 的发展。在目标 1 中，我假设 TTP KD 通过上调 PPAR?? 介导脂质稳态的变化。我将从有或没有 TTP 缺失的小鼠中分离原代肝细胞，并通过 RNA 测序测量脂质摄取、脂质含量、β-氧化活性和代谢基因表达的变化来确定 TTP 对脂质代谢的影响。所有实验将在TTP KO/PPAR的设置下重复？ KD。我还会确定TTP是否直接调节PPAR？？通过对 PPAR?? 内的 3'-UTR ARE 进行删除研究。在目标 2 中，我假设 TTP KD 通过上调 PDK4 介导葡萄糖稳态的变化。我将从有或没有 TTP 缺失的小鼠中分离原代肝细胞，并通过 RNA 测序测量葡萄糖摄取、葡萄糖产生、葡萄糖氧化和糖异生/糖酵解基因表达的变化，确定 TTP 对葡萄糖代谢的影响。所有实验将在 TTP KO/PDK4 KD 的设置中重复。我还将通过对 PDK4 内的 3'-UTR ARE 进行删除研究来确定 TTP 是否直接调节 PDK4。最后，在目标 3 中，我假设 TTP 介导对 II 型糖尿病发展的保护作用。我将使 TTP/TNFR1/2 KO 和 TNFR1/2 KO（对照）小鼠接受高脂肪饮食，并根据血糖和胰岛素水平评估这些小鼠的糖尿病进展情况。这些研究方向有望增进我们对 TTP 在糖尿病中作用的认识，并可能导致新型糖尿病疗法的开发。