Adipocyte dysfunction: modulation of weight loss associated miR

代谢综合征（MetS）的患病率不断增加，是一个主要的公共卫生负担。其潜在机制涉及肥胖相关的代谢应激脂肪细胞和脂肪组织中促炎巨噬细胞的积累。促炎性巨噬细胞与脂肪细胞的相互作用导致脂肪组织功能障碍，并促进局部胰岛素抵抗、脂质溢出和全身性低度炎症，目前生活方式诱导的减肥被认为是改善代谢综合征、预防代谢综合征患者2型糖尿病和心血管疾病的有效疗法。然而，关于促进代谢综合征患者脂肪细胞功能障碍可逆性的分子途径的信息充其量也是稀缺的。脂肪细胞和脂肪组织巨噬细胞通过改变细胞特异性基因表达对体重减轻做出反应，这是由microRNA（miR）调节的。因此，调节脂肪和巨噬细胞特异性miR表达可能代表改善MetS个体脂肪组织功能障碍的分子靶点。为了鉴定与体重减轻相关的miR，我们分析了MetS个体皮下脂肪组织中的mRNA和miR表达。74名年龄在45至55岁之间的非吸烟、非糖尿病男性，根据国际糖尿病联盟指南的定义患有MetS，随机分配至6个月远程监测生活方式诱导的减肥干预组或对照组。这项研究的第一个结果已经由我们在2016年发表（Scientific Reports，Nature Publishing Group）。通过配对分析，我们确定了7种在生活方式诱导的体重减轻后受到不同调节的miR。目标预测分析显示，两种特定的miR在不同调节的基因中具有潜在的结合位点，这些基因可以主要通过脂质代谢和巨噬细胞活性的功能进行聚类。我们现在的目标是利用这些数据，以确定所确定的体重减轻相关的miR的调节是否调节脂肪细胞在脂肪形成、ROS产生、胰岛素敏感性、巨噬细胞分化、巨噬细胞活化和脂肪细胞-巨噬细胞相互作用方面的功能。由于小鼠直系同源物仅存在于已鉴定的miR的一个子集中，并且由于MetS和生活方式诱导的基因表达的病理生理机制方面的物种差异是非常可能的，因此我们将使用人类体外模型分析已鉴定的miR在脂肪细胞和巨噬细胞上的功能。通过这种方法，我们希望确定改善肥胖相关脂肪细胞功能障碍的新途径。将研究以下目标：目标1a：HSA-miR-548 y对脂肪细胞VLDL摄取的影响目标1b：HSA-miR-548 y对巨噬细胞分化和活化的影响目标2：已鉴定的miR对脂肪细胞分化、ROS产生和胰岛素敏感性的影响目标3：鉴定的miR对脂肪细胞-巨噬细胞相互作用的影响

Increasing prevalence of the metabolic syndrome (MetS) represents a major public health burden. The underlying mechanism involves obesity associated metabolically stressed adipocytes and accumulation of proinflammatory macrophages in adipose tissue. Interaction between proinflammatory macrophages and lipid laden adipocytes is suggested to contribute to adipose tissue dysfunction and to promote local insulin resistance, lipid spillover and systemic low-grade inflammation.So far, lifestyle-induced weight loss is regarded as efficient therapy to ameliorate MetS and to prevent type 2 diabetes and CVD in individuals with MetS. However, information about the molecular pathways that promote reversibility of adipocyte dysfunction in patients with MetS is scarce at best. Adipocytes and adipose tissue macrophages react to weight loss by alterations of cell specific gene expression, which is regulated by microRNA´s (miR). Hence, modulation of adipose and macrophage specific miR expression may represent a molecular target to improve adipose tissue dysfunction in individuals with MetS. To identify weight loss associated miR, we analyzed mRNA and miR expression in subcutaneous adipose tissue of individuals with MetS. 74 non-smoking, non-diabetic men aged between 45 and 55 years with MetS as defined by the International Diabetes Federation guidelines were randomized to a 6 months tele-monitored lifestyle-induced weight loss intervention group or to a control arm. First results of this study were already published by us in 2016 (Scientific Reports, Nature Publishing Group). By paired analysis we identified 7 miR that were differently regulated following lifestyle-induced weight loss. Target prediction analysis revealed that two specific miR have potential binding sites in differently regulated genes that can be predominantly clustered by function for lipid metabolism and for macrophage activity. We now aim to exploit these data to ascertain whether modulation of the identified weight loss associated miR regulate adipocyte function in regard to adipogenesis, ROS production, insulin sensitivity, macrophage differentiation, macrophage activation and adipocyte-macrophage interaction. As mouse orthologues exist only for a subset of identified miR and as species differences in regard to the pathophysiological mechanisms underlying MetS and lifestyle induced gene expression are highly likely, we will analyze the function of identified miR on adipocytes and macrophages using human in vitro models. With this approach we hope to identify new pathways ameliorating obesity related adipocyte dysfunction.The following goals will be investigated:Goal 1a: Impact of HSA-miR-548y on adipocyte VLDL uptakeGoal 1b: Impact of HSA-miR-548y on macrophage differentiation and activation Goal 2: Impact of identified miR on adipocyte differentiation, ROS production and insulin sensitivityGoal 3: Impact of identified miR on adipocyte-macrophage interaction