Mechanism of Gdf3 action to limit insulin sensitivity in obesity

Gdf3 限制肥胖胰岛素敏感性的机制

• 批准号: 10457422
• 负责人: ALEXANDER BANKS
• 金额: $ 63.8万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10457422
• 关键词: Acute; Address; Adipocytes; Adipose tissue; Affect; Affinity; Alanine; Antidiabetic Drugs; Biochemical; Blood Glucose; Body Temperature; Body Weight decreased; CRISPR screen; CRISPR/Cas technology; Cardiovascular Diseases; Cells; Clinical; Death Rate; Development; Diabetes Mellitus; Diabetic mouse; Down-Regulation; Ectopic Expression; Energy Metabolism; Fatty acid glycerol esters; Future; Gene Expression; Genetic; Genetic Transcription; Glucose; Glycosylated hemoglobin A; Goals; Health; High Fat Diet; Immune system; Impairment; In Vitro; Indirect Calorimetry; Insulin Resistance; Investigation; Knock-in; Knock-out; Knockout Mice; Ligands; Link; LoxP-flanked allele; Malignant Neoplasms; Measurement; Mediating; Mediator of activation protein; Metabolic; Metabolism; Methods; Modality; Modeling; Molecular Target; Monitor; Morbidity - disease rate; Mouse Strains; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nuclear Hormone Receptors; Nutrient; Obesity; PPAR gamma; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Pharmacology; Phosphorylation; Population; Process; Proteins; Reporter; Role; Serine; Signal Transduction; Signaling Molecule; Stroke; System; Technology; Testing; Thermogenesis; Thiazolidinediones; Thinness; Tissues; Weight Gain; Work; blood glucose regulation; bone fragility; comorbidity; design; diabetic patient; energy balance; experimental study; feeding; gain of function; genome-wide; glucose monitor; glucose uptake; growth differentiation factor 3; improved; inhibitor; innovation; insulin sensitivity; large datasets; lipid biosynthesis; loss of function; metabolic rate; mortality; mouse model; novel therapeutics; prevent; programs; receptor; response; side effect; small hairpin RNA; therapeutic evaluation; therapeutic target; tool; transcription factor; wireless

Project Summary The thiazolidinediones (TZDs) are powerful anti-diabetic drugs whose use in treating type 2 diabetes is limited by adverse side effects. The goal of this proposal is a biochemical investigation into the mechanism that separates the positive metabolic effects of TZDs to lower glucose from their well-characterized negative side effects. PPARγ, a molecular target of the TZDs, regulates systemic insulin sensitivity by promoting formation of new adipocytes. However, we show that the TZDs have a second biochemical function on PPARγ, to block phosphorylation of serine 273 (pS273). We find that phosphorylation of PPARγ at serine 273 promotes insulin resistance without affecting adipogenesis. Reversing this phosphorylation with pharmacological or genetic inhibition is sufficient to promote insulin sensitivity and increase thermogenic responses to cold. We propose that one of the main mechanisms by which phosphorylation of PPARγ at serine 273 promotes insulin resistance is through increased expression of growth differentiation factor 3 (Gdf3). Gdf3 is a secreted protein in the TGF- /BMP superfamily and a negative regulator of BMP signaling. In adipose tissue, BMP proteins contribute to insulin sensitivity and thermogenesis. We therefore propose that elevated levels of Gdf3 in obesity are the cause of insulin resistance mediated by PPARγ S273 phosphorylation. Indeed, we show that ectopic expression of Gdf3 is sufficient to cause insulin resistance in lean mice. In this proposal we examine the contribution of Gdf3 to the pathogenesis of obesity and insulin resistance. We predict that blocking Gdf3 levels or activity will restore whole-body insulin sensitivity and promote thermogenesis. We will interrogate the role of Gdf3 on glucose homeostasis and obesity using both acute gain-of-function and loss-of-function models. We will utilize innovative new wireless continuous glucose monitoring technology concurrently with indirect calorimetry to achieve high- precision measurements of insulin resistance, energy balance, and circulating nutrient availability. We will determine whether Gdf3 is the mechanism linking PPARγ S273 phosphorylation and insulin resistance. We will also determine whether Gdf3 requires BMP signaling through SMAD1/5/8 proteins. Finally, we will perform an unbiased investigation into the pathways required for Gdf3 signaling using a genome-wide CRISPR/Cas9 knockout screen. This hypothesis suggests a new therapeutic modality which harnesses a specific beneficial aspect of TZD treatment which is independent of TZD-associated side effects. The results from this proposal will definitively determine if Gdf3 is a suitable target for promoting metabolic health.

项目摘要 噻唑烷二酮（TZD）是强大的抗糖尿病药物，用于治疗2型糖尿病的使用受到限制 通过不利的副作用。该提案的目的是对这种机制的生化研究 将TZD的阳性代谢作用与良好的负面负面降低葡萄糖的阳性代谢作用 效果。 PPARγ是TZDS的分子靶标，通过促进形成的形成来调节全身胰岛素敏感性 新的脂肪细胞。但是，我们表明TZD在PPARγ上具有第二个生化功能，以阻止 丝氨酸273（PS273）的磷酸化。我们发现丝氨酸273上PPARγ的磷酸化促进了胰岛素 耐药性而不会影响脂肪形成。用药理学或遗传来逆转这种磷酸化 抑制足以促进胰岛素敏感性并增加对冷的热反应。我们提出了这一点 丝氨酸273促进胰岛素抵抗的PPARγ的光谱化的主要机制之一是 通过增加生长分化因子3的表达（GDF3）。 GDF3是TGF-的分泌蛋白 /BMP超家族和BMP信号的负调节剂。在脂肪组织中，BMP蛋白有助于 胰岛素敏感性和热发生。因此，我们建议肥胖症中GDF3水平升高是原因 由PPARγS273磷酸化介导的胰岛素抵抗。确实，我们证明了对 GDF3足以在瘦小小鼠中引起胰岛素耐药性。在此提案中，我们研究了GDF3的贡献 肥胖和胰岛素抵抗的发病机理。我们预测阻止GDF3级别或活动将恢复 全身胰岛素敏感性并促进生热。我们将询问GDF3在葡萄糖上的作用 使用急性功能获得和功能丧失模型，体内平衡和肥胖。我们将利用创新 新的无线连续葡萄糖监测技术以及间接量热法，以实现高 胰岛素抵抗，能量平衡和循环营养物的可用性的精确测量。我们将 确定GDF3是否是连接PPARγS273磷酸化和胰岛素抵抗的机制。我们将 还要确定GDF3是否需要通过SMAD1/5/8蛋白质信号传导。最后，我们将执行 使用全基因组CRISPR/CAS9对GDF3信号传导所需的途径进行公正的研究 淘汰赛屏幕。该假设提出了一种新的热模式，可以利用特定的有益 与TZD相关的副作用无关的TZD处理方面。该提议的结果将 明确确定GDF3是否是促进代谢健康的合适靶标。