Developmental genes, miRNAs and adipose tissue

项目摘要/摘要 这是NIH拨款DK082659的竞争性续订，标题为“发育基因、miRNAs和 脂肪组织“。肥胖正在以流行的比例增加，是发病的主要推动力。 2型糖尿病和代谢综合征。在过去的十年里，很明显，白人和 棕色脂肪是异质性的。因此，内脏水分的积累与胰岛素抵抗和 增加代谢性疾病的风险，而皮下积聚水分甚至可能具有保护作用。 这至少部分是由于脂肪细胞之间固有的，即细胞自主的功能差异。 这些仓库。事实上，我们和其他人最近的研究表明，有遗传和功能 单个储存库内白色脂肪细胞的异质性。利用生物信息学方法和单细胞 克隆，我们现在已经确定了至少三类白色脂肪细胞的谱系追踪标记。 除了以上这些之外。我们还发现，不同的脂肪库在miRNAs的表达上存在差异 在肥胖和衰老过程中，脂肪组织中的miRNAs和miRNA加工发生了变化。 此外，对miRNA处理酶的脂肪特异性敲除改变了WAT和BAT的发育， 全身糖和脂代谢，以及对压力的反应。在令人振奋的最近数据中，我们已经表明 脂肪组织是循环外体miRNAs的主要来源，这些miRNAs可以调节基因表达 在其他组织中，形成了一种新的脂肪与其他组织沟通的模式。这些数据导致了 两个相互关联的假设。首先，我们假设--除了将脂肪组织分类为 白色、棕色和米色脂肪-白色脂肪细胞本身在性质上是不同的，这 异质性决定了基因表达和脂肪细胞功能的差异。其次，这些不同 白色和棕色脂肪细胞的miRNA表达不同，这些miRNAs的子集是 以外切体的形式释放到循环中，在那里它们扮演着脂肪对其他 纸巾。下一批赠款的具体目标是：1)完成白色脂肪细胞的鉴定 使用新确定的谱系标记的异质性，并使用单细胞RNAseq进行扩展以定义 不同亚型的前脂肪细胞/脂肪细胞在代谢调节中的功能和作用不同。2) 继续探索脂肪组织来源的循环外体miRNAs在代谢中的作用 体外鉴定控制脂肪细胞miRNA外切体分泌的分子特征 体内鉴定脂肪和其他组织来源的循环外体miRNAs的方法。我们还将 检测脂肪营养不良和肥胖患者血清中的外体miRNAs，并评估 外体miRNAs调节其他组织中的基因表达。这些数据加在一起将加深我们的 了解脂肪器官的复杂性并阐明循环脂肪衍生的作用 外体miRNAs作为调节新陈代谢的新型脂肪因子。

Project Abstract/Summary This is a competitive renewal of NIH grant DK082659 entitled “Developmental Genes, miRNAs and Adipose Tissue”. Obesity is increasing at epidemic proportions and is a major driving force in the pathogenesis of type 2 diabetes and metabolic syndrome. Over the past decade it has become clear that both white and brown fat are heterogeneous. Thus, accumulation of visceral WAT is associated with insulin resistance and increased risk of metabolic disease, whereas accumulation of subcutaneous WAT may even be protective. This is due, at least in part, to intrinsic, i.e., cell-autonomous, functional differences between adipocytes in these depots. Indeed, recent studies by us and others have shown that there is genetic and functional heterogeneity of white adipocytes within a single depot. Using bioinformatics approaches and single cell cloning, we have now identified lineage tracing markers for at least three classes of white adipocytes in addition to those above. We have also found that different adipose depots differ in their expression of miRNAs and that there are alterations in miRNAs and miRNA processing in adipose tissue in obesity and aging. Furthermore, fat-specific knockout of the miRNA processing enzyme Dicer alters WAT and BAT development, systemic glucose and lipid metabolism, and response to stress. In exciting recent data, we have shown that adipose tissue is a major source of circulating exosomal miRNAs and that these can regulate gene expression in other tissues, forming a novel mode of adipose communication with other tissues. These data have led to two inter-related hypotheses. First, we hypothesize that - in addition to classification of adipose tissue into white, brown and beige fat - white adipocytes themselves are heterogeneous in nature and that this heterogeneity programs differences in mRNA expression and adipocyte function. Secondly, these different classes of white and brown adipocytes differ in their miRNA expression and that a subset of these miRNAs is released in exosomes into the circulation where they act as novel regulators of the effects of fat in other tissues. The specific aims for the next grant period are to: 1) Complete the characterization of white adipocyte heterogeneity using the newly identified lineage markers and expand this using single cell RNAseq to define different subtypes of preadipocyte/adipocytes which differ in function and role in metabolic regulation. 2) Continue to explore the role of adipose tissue derived circulating exosomal miRNAs in metabolism by identifying the molecular signature governing adipocyte miRNA exosomal secretion in vitro and developing an in vivo method for identification of fat- and other tissue-derived circulating exosomal miRNAs. We will also assess exosomal miRNAs in serum of humans with lipodystrophy and obesity and assess the ability of exosomal miRNAs to regulate gene expression in other tissues. Together these data will deepen our understanding of the complex nature of the adipose organ and elucidate the role of circulating adipose-derived exosomal miRNAs as novel adipokines in regulation of metabolism.