Exosomes and insulin action in metabolically healthy and unhealthy obesity

项目总结 胰岛素抵抗通常与肥胖有关，是导致 与肥胖相关的代谢性疾病(如非酒精性脂肪性肝病和2型糖尿病)。多数 当表现为糖耐量和胰岛素时 敏感度。然而，有一小部分人服从 过度肥胖的不良代谢影响。更好地了解导致经济衰退的机制 MHO和MUO患者代谢功能的差异可以提供重要的机制 对肥胖代谢异质性的洞察并可能确定新的治疗靶点 干预。 小的细胞外小泡(SEV，或外体)是由全身的细胞产生并输送 生物活性分子通过血液调节多个器官系统的代谢过程。研究项目： 小鼠发现，从脂肪组织释放的SEV调节胰岛素敏感性，并含有调节性 改变胰岛素信号的miRNAs和生物活性脂质。与这些发现一致的是，我们最近发现 肥胖和NAFLD患者的血浆和脂肪组织SEV抑制胰岛素信号转导 培养的肌管，这表明SEV也有助于调节人的胰岛素敏感性。 在这项建议中，我们将评估从血浆和 脂肪组织(AT)外植体培养取自三组受试者。我们将描述 基于肥胖和代谢健康的参与者：1)代谢健康的瘦肉(MHL，BMI 18.5-24.9 kg/m2 和正常胰岛素敏感性，定义为胰岛素抵抗的稳态模型评估(HOMA-IR)。 2)代谢健康肥胖(MHO，BMI 30.0-44.9 kg/m2和HOMA-IR；2)；3)代谢不健康 肥胖(MUO，BMI 30.0-44.9 kg/m2和HOMA-IR&GT；2.5)。我们假设：i)来自血浆和脂肪的SEV 与来自MUO患者的SEV相比，MUO患者的组织对胰岛素作用有不利影响 是MHL还是MHO；II)这些代谢差异与miRNA和MHO的SEV含量的差异有关 生物活性脂类；iii)MUO患者体重适度减轻10%会改变miRNA和脂质含量 血浆和脂肪组织SEV及其对胰岛素作用的影响。 将处理以下具体目标：1)确定从血浆和 MHL、MHO和MUO参与者的脂肪组织：I)胰岛素作用、基因表达和蛋白质谱 在体外和在小鼠体内的细胞；2)确定miRNA和生物活性脂谱的差异 从MHL、MHO和MUO组获得的脂肪组织SEV；以及3)确定10%的重量 MUO组丢失诱导的胰岛素敏感性增加将改变血浆和脂肪组织SEV miRNA 和脂类含量，改善血浆和脂肪组织SEV对胰岛素作用的不良影响 在体外和在小鼠体内。这些发现将为未来对人的研究提供基础 评估SEV作为预防和治疗高血压患者代谢并发症的治疗靶点的潜力 肥胖。

PROJECT SUMMARY Insulin resistance is commonly associated with obesity and is a major contributor to the development of obesity-related metabolic diseases, (e.g. nonalcoholic fatty liver disease [NAFLD] and type 2 diabetes). Most when characterized by glucose tolerance and insulin sensitivity. However, a subset of people with obesit adverse metabolic effects of excess adiposity. A better understanding of the mechanisms responsible for the differences in metabolic function between people with MHO and MUO can provide important mechanistic insights into the metabolic heterogeneity of obesity and possibly identify novel targets for therapeutic intervention. Small extracellular vesicles (sEVs, or exosomes) are produced by cells throughout the body and deliver bioactive molecules via the bloodstream to regulate metabolic processes in multiple organ systems. Studies in mice have found that sEVs released from adipose tissue modulate insulin sensitivity and contain regulatory miRNAs and bioactive lipids that alter insulin signaling. Consistent with these findings, we recently found that plasma and adipose tissue sEVs obtained from people with obesity and NAFLD impair insulin signaling in cultured myotubes, suggesting sEVs also contribute to the regulation of insulin sensitivity in people. In this proposal, we will evaluate the metabolic effects and cargo content of sEVs isolated from plasma and adipose tissue (AT) explant cultures obtained from three groups of participants. We will characterize participants based on adiposity and metabolic health: 1) metabolically healthy lean (MHL, BMI 18.5-24.9 kg/m2 and normal insulin sensitivity, defined as homeostatic model assessment of insulin resistance (HOMA-IR) <2); 2) metabolically healthy obese (MHO, BMI 30.0-44.9 kg/m2 and HOMA-IR<2); and 3) metabolically unhealthy obesity (MUO, BMI 30.0-44.9 kg/m2 and HOMA-IR>2.5). We posit that: i) sEVs from plasma and adipose tissue in people who are MUO have adverse effects on insulin action compared with sEVs from people who are MHL or MHO; ii) these metabolic differences are associated with differences in sEV content of miRNA and bioactive lipids; and iii) moderate 10% weight loss in people with MUO changes the miRNA and lipid content of plasma and adipose tissue sEVs and their effects on insulin action. The following specific aims will be addressed: 1) determine the effects of sEVs obtained from plasma and adipose tissue of MHL, MHO and MUO participants on: i) insulin action, gene expression and protein profile in cells vitro and in mice in vivo; 2) identify differences in miRNA and bioactive lipid profiles of plasma and adipose tissue sEVs obtained from MHL, MHO and MUO groups; and 3) determine whether a 10% weight loss-induced increase in insulin sensitivity in the MUO group will alter plasma and adipose tissue sEVs miRNA and lipid content and ameliorate the adverse effects of plasma and adipose tissue sEVs on insulin action in in vitro and in mice in vivo. These findings will provide the foundation for future studies in people designed to assess the potential of sEVs as a therapeutic target to prevent and treat the metabolic complications of obesity.