Mechanisms by which hepatocyte extracellular miRNAs mediate peripheral insulin sensitivity

肝细胞胞外 miRNA 介导外周胰岛素敏感性的机制

基本信息

批准号：
10209866
负责人：
Wei Ying
金额：
$ 39.47万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-01 至 2026-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10209866
关键词：
Adipocytes Adipose tissue Antidiabetic Drugs Beta Cell Blood Circulation Cells Development Diabetes Mellitus Endocrine Epidemic Exhibits Future Genes Hepatic Hepatocyte High Fat Diet Homeostasis Human Impairment In Vitro Inflammation Insulin Insulin Resistance Knock-out Lead Macrophage Activation Mediating Medical Metabolic Metabolic Diseases Metabolic syndrome Methods MicroRNAs Molecular Morbidity - disease rate Mus Muscle Fibers Non-Insulin-Dependent Diabetes Mellitus Obesity Pancreas Pathogenicity Patients Peripheral Play Prediabetes syndrome Regulation Role Skeletal Muscle System Therapeutic Thinness Thiouracil Tissues Transgenic Mice Transgenic Organisms Type 2 diabetic Work base diabetic patient diet-induced obesity disorder control driving force early-onset obesity experimental study extracellular extracellular vesicles feeding glycemic control impaired glucose tolerance improved in vivo insight insulin secretion insulin sensitivity insulin sensitizing drugs metabolic phenotype microRNA biomarkers mortality mouse model novel obese patients obesity development obesity treatment predictive marker prevent response vesicular release

项目摘要

Obesity-induced insulin resistance is the major determinant of metabolic syndrome, which precedes the development of Type 2 diabetes mellitus and is thus the driving force behind the emerging diabetes epidemic. Current anti-diabetic therapeutics are available, but are inadequate to control the disease in most patients and there is a large unmet medical need for better methods of treating diabetes to prevent morbidity and mortality. Our recent work has led to the discovery that obesity induces a dynamic change in secretion of hepatic extracellular vesicle (EV) miRNAs that exert profound impacts on insulin producing cells and peripheral insulin sensitivity. Depletion of hepatic extracellular miRNAs in the hepatocyte-specific Rab27KO mice resulted in impaired glucose tolerance and insulin sensitivity at the early onset of obesity. We further demonstrated that 4wks high-fat diet feeding (4wks-HFD)-induced hepatic EV miRNAs can reduce the insulin resistance of obese recipient mice. In addition, the 4wks-HFD EV treatment significantly enhanced the insulin secretion and proliferation of beta cells in vitro and in vivo. By contrast, prolonged obesity induced secretion of pathogenic hepatocyte EV miRNAs that blunted insulin sensitivity of lean recipient WT mice. Consistently, the mice without hepatic extracellular miRNAs by knockout of hepatic Rab27 showed a reduction in insulin resistance after 16 weeks HFD feeding. miRNA-free EVs derived from YBX1KO hepatocytes had minimal effects on the metabolic phenotypes of recipient mice, suggesting miRNAs as key cargoes within these EVs. Using a novel thiouracil tagging method, we identified that miR-3075-5p, a highly enriched miRNAs in 4wks-HFD EVs, can be efficiently incorporated into target cells and improves cellular insulin responses through repressing Fa2h expression. In addition, the miR-434-3p-Map2k6 regulatory axis plays a critical role in promoting proinflammatory activation of macrophages, which can subsequently exacerbate tissue inflammation and insulin resistance. These results lead to the conclusion that hepatic EV miRNAs are important endocrine molecules regulating functions of insulin-producing and -targeting cells in obesity. This proposal sees to build on this newly identified hepatic EV miRNAs regulatory system to reveal the underlying cellular and molecular mechanisms of obesity-induced insulin resistance. We will further determine the mechanisms by which hepatic EV miRNAs modulate functions of beta cell and insulin sensitizing cells in response to obesity. With the proposed experiments, we will develop miR-3075-5p as an insulin sensitizer molecule and explore the pathogenic effect of miR-434-3p in obesity. This therapeutic strategy could be used for the treatment of obese patients with insulin resistance pre-diabetic state. This would lead to improved glycemic control adding a new component in our therapeutic armamentarium for the treatment of this widespread metabolic disease. Finally, using the thiouracil tagging method, we will identify the hepatic extracellular miRNAs in circulation as biomarkers predicting the insulin resistance state in obesity.

肥胖引起的胰岛素抵抗是代谢综合征的主要决定因素，代谢综合征先于 2 型糖尿病的发展，因此是新出现的糖尿病流行背后的驱动力。目前的抗糖尿病疗法是可用的，但不足以控制大多数患者的疾病，并且对于治疗糖尿病以预防发病率和死亡率的更好方法存在巨大的未满足的医疗需求。我们最近的工作发现，肥胖会引起肝细胞外囊泡 (EV) miRNA 分泌的动态变化，从而对胰岛素生成细胞和外周胰岛素敏感性产生深远影响。肝细胞特异性 Rab27KO 小鼠肝细胞外 miRNA 的耗竭导致肥胖早期糖耐量和胰岛素敏感性受损。我们进一步证明，4周高脂饮食喂养（4wks-HFD）诱导的肝脏EV miRNA可以降低肥胖受体小鼠的胰岛素抵抗。此外，4 周 HFD EV 治疗显着增强了胰岛素水平体外和体内β细胞的分泌和增殖。相比之下，长期肥胖会诱导致病性肝细胞 EV miRNA 的分泌，从而削弱瘦受体 WT 小鼠的胰岛素敏感性。一致地，通过敲除肝脏 Rab27 而没有肝细胞外 miRNA 的小鼠在 HFD 喂养 16 周后表现出胰岛素抵抗的降低。来自 YBX1KO 肝细胞的不含 miRNA 的 EV 对受体小鼠的代谢表型影响极小，表明 miRNA 是这些 EV 中的关键货物。使用一种新的硫尿嘧啶标记方法，我们发现 miR-3075-5p（4wks-HFD EV 中高度富集的 miRNA）可以有效地整合到靶细胞中，并通过抑制 Fa2h 表达来改善细胞胰岛素反应。此外，miR-434-3p-Map2k6 调控轴在促进巨噬细胞的促炎症激活，从而随后加剧组织炎症炎症和胰岛素抵抗。这些结果得出这样的结论：肝脏 EV miRNA 是调节肥胖中胰岛素产生和靶向细胞功能的重要内分泌分子。该提案旨在以新发现的肝脏 EV miRNA 调节系统为基础，揭示肥胖引起的胰岛素抵抗的潜在细胞和分子机制。我们将进一步确定肝脏 EV miRNA 调节 β 细胞和胰岛素敏化细胞功能以应对肥胖的机制。通过所提出的实验，我们将开发 miR-3075-5p 作为胰岛素增敏剂分子，并探索 miR-434-3p 在肥胖中的致病作用。该治疗策略可用于治疗糖尿病前期胰岛素抵抗状态的肥胖患者。这将改善血糖控制，在我们的治疗设备中添加新的成分来治疗这种广泛的代谢疾病。最后，使用硫尿嘧啶标记方法，我们将鉴定循环中的肝细胞外 miRNA，作为预测肥胖胰岛素抵抗状态的生物标志物。