Role of extracellular vesicles in the regulation of immunometabolism in obesity

项目摘要 肥胖症在世界范围内的流行已经达到了大流行的程度。肥胖有很强的炎症性 基础，这与2型糖尿病(T2D)和非酒精性疾病的发展有关 脂肪肝(NASH)。然而，肥胖引发异常炎症的机制并非如此。 清楚地定义了。在这项研究中，我们的目的是证明在肥胖中，mTOR途径增强了 促炎症细胞外小泡(EVS)的生物发生和分泌 来自肝细胞的细胞外RNA(ExRNAs)，以及这些肝细胞来源的EV(H-EV)导致 反常炎症。 EV包括外切体(30-150 nm)和微泡(100-1000 nm)，可从多种类型的细胞中释放出来 进入细胞外空间，并分布在体液中。这些电动汽车被邻近的或 并随后调节受体细胞的功能。使用新的计算方法9，我们 已发现调节EV生物发生的基因的人类遗传变异与 代谢综合征，特别是T2D。青春期肥胖患者EVS分析 减肥手术表明，血清EV浓度与新陈代谢改善呈负相关 在胰岛素敏感性和术后炎症方面，具有独特的EVS的exRNA图谱。此外，我们最新的 已建立的允许在体内监测特定细胞类型衍生EVS的小鼠模型表明，在 对于肥胖，H-EV的行为就像巨噬细胞识别的病原体，并引发炎症。从机械上讲， 我们发现，在肝细胞中，胰岛素-mTOR途径促进EVS的分泌，而胰岛素-mTOR途径可促进EVS的分泌。 刺激的EV在激活巨噬细胞方面具有更强的促炎作用。我们还发现，一个 RNA沉默机制的组成部分是促炎EVS的介体，是 EV诱导巨噬细胞活化。这些初步数据表明，混合动力电动汽车发挥着独特和关键的作用， 这让我们假设，在高胰岛素血症的发展过程中，肝细胞分泌 病理性EV携带独特的exRNA，可被受体巨噬细胞感知，促进 反常炎症。 这项建议中的研究将：(1)定义赋予H- EVS，(2)确定巨噬细胞中RNA沉默机制作为促炎介质的作用 EVS，以及(3)评估EVS在肥胖患者免疫代谢中的作用。 通过利用我们的新型小鼠模型和获取人类样本，我们的系统方法 将展示新的机制，关于H-EVS的致病性如何参与 高胰岛素血症和肥胖症的炎症进展。

Project Summary The worldwide prevalence of obesity has reached pandemic proportions. Obesity has strong inflammatory underpinnings, which are associated with the development of type 2 diabetes (T2D) and non-alcoholic steatohepatitis (NASH). However, the mechanisms by which obesity provokes aberrant inflammation are not clearly defined. In this study, we aim to demonstrate that in obesity, the mTOR pathway enhances the biogenesis and secretion of pro-inflammatory extracellular vesicles (EVs) carrying a distinct set of extracellular RNAs (exRNAs) from hepatocytes and that these hepatocyte-derived EVs (H-EVs) cause the aberrant inflammation. EVs, including exosomes (30–150 nm) and microvesicles (100–1000 nm), are released from many cell types into the extracellular space and are distributed in body fluids. These EVs are taken up by neighboring or distant cells and subsequently modulate functions of recipient cells. Using novel computational methods9, we identified strong associations between human genetic variations of genes regulating EV biogenesis and metabolic syndrome, particularly T2D. Our analyses of EVs from adolescent obese patients undergoing bariatric surgery have shown that serum EV concentration is inversely correlated to metabolic improvements in insulin sensitivity and inflammation post-surgery, with unique EVs’ exRNA profiles. Further, our newly established mouse model that permits monitoring of specific cell type-derived EVs in vivo indicates that in obesity, H-EVs behave like a pathogen recognized by macrophages and induce inflammation. Mechanistically, we found that in hepatocytes, the insulin-mTOR pathway enhances secretion of EVs and that insulin- stimulated EVs are more pro-inflammatory in activating macrophages. We have also discovered that a component of the RNA silencing machinery is a mediator of the pro-inflammatory EVs and is required for the EV-induced macrophage activation. These preliminary data suggest unique and pivotal roles for H-EVs, leading us to hypothesize that during the development of hyperinsulinemia, hepatocytes secrete pathologic EVs carrying unique exRNAs which are sensed by recipient macrophages, promoting aberrant inflammation. Studies in this proposal will: (1) define the molecular pathway that confers the proinflammatory trait to the H- EVs, (2) determine the role of RNA silencing machinery in macrophages as a mediator of pro-inflammatory EVs, and (3) evaluate the role of EVs in immunometabolism in human obese patients. By utilizing our novel mouse models coupled with access to human samples, our systematical approaches will demonstrate novel mechanisms concerning how the pathogenicity of H-EVs is involved in the development of inflammation in hyperinsulinemia and obesity.