Exosomes and insulin action in metabolically healthy and unhealthy obesity

项目摘要 胰岛素抵抗通常与肥胖相关，并且是导致肥胖的主要因素。 肥胖相关的代谢性疾病（如非酒精性脂肪肝[NAFLD]和2型糖尿病）。最 当以葡萄糖耐量和胰岛素为特征时 灵敏度然而，有一小部分肥胖症患者 过度肥胖对新陈代谢的不利影响。更好地了解造成这些问题的机制， MHO和MUO患者之间代谢功能的差异可以提供重要的机制 深入了解肥胖症的代谢异质性，并可能确定新的治疗靶点， 干预 小的细胞外囊泡（sEV或外来体）由全身的细胞产生，并递送给 生物活性分子通过血流调节多器官系统的代谢过程。研究 小鼠已经发现，从脂肪组织释放的sEV调节胰岛素敏感性，并含有调节胰岛素敏感性的基因。 miRNAs和生物活性脂质改变胰岛素信号。与这些发现一致，我们最近发现， 从患有肥胖和NAFLD的人获得的血浆和脂肪组织sEV损害胰岛素信号传导， 这表明sEV也有助于调节人的胰岛素敏感性。 在本提案中，我们将评估从血浆中分离的sEV的代谢作用和货物含量， 从三组参与者获得的脂肪组织（AT）外植体培养物。我们将描述 基于肥胖和代谢健康的参与者：1）代谢健康的瘦型（MHL，BMI 18.5-24.9 kg/m2 胰岛素敏感性正常，定义为胰岛素抵抗的稳态模型评估（HOMA-IR）<2）; 2)代谢健康的肥胖（MHO，BMI 30.0- 44.9kg/m2和HOMA-IR<2）;和3）代谢不健康的 肥胖（MUO，BMI 30.0- 44.9kg/m2和HOMA-IR>2.5）。我们证明：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或MHO; ii）这些代谢差异与miRNA的sEV含量的差异相关， iii）MUO患者体重减轻10%，改变了微RNA和脂质的含量， 血浆和脂肪组织sEV及其对胰岛素作用的影响。 1）确定从血浆获得的sEV的作用， MHL、MHO和MUO参与者的脂肪组织的胰岛素作用、基因表达和蛋白质谱： 细胞体外和小鼠体内; 2）鉴定血浆中miRNA和生物活性脂质谱的差异， 从MHL、MHO和MUO组获得的脂肪组织sEV;和3）确定10%重量的sEV是否 MUO组中胰岛素敏感性的丧失诱导的增加将改变血浆和脂肪组织sEVs miRNA 和脂质含量，并改善血浆和脂肪组织sEV对胰岛素作用的不良影响， 体外和小鼠体内。这些发现将为未来的研究提供基础， 评估sEV作为治疗靶点预防和治疗代谢并发症的潜力。 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.