ADSF/resistin function in adipocyte differentiation

ADSF/抵抗素在脂肪细胞分化中的功能

• 批准号: 7250242
• 负责人: Hei Sook Sul
• 金额: $ 30.92万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7250242
• 关键词: 1-Phosphatidylinositol 3-Kinase; 2,4-thiazolidinedione; 3T3-L1 Cells; Adipocytes; Adipose tissue; Affinity; Affinity Chromatography; Animals; Antidiabetic Drugs; Attenuated; Binding; Biochemical Genetics; Cell Surface Proteins; Cysteine; Development; Diet; Dominant-Negative Mutation; Fasting; Feedback; Fluorescence-Activated Cell Sorting; Genes; Genetic; Goals; Human; In Vitro; Insulin; Insulin Resistance; Label; Liver; Mediating; Membrane; Messenger RNA; Mitogen-Activated Protein Kinases; Molecular; Names; Non-Insulin-Dependent Diabetes Mellitus; Obese Mice; Obesity; Pathway interactions; Phosphoinositide-3-Kinase, Catalytic, Gamma Polypeptide; Preparation; Process; Protein Overexpression; Research; Signal Pathway; Signal Transduction; Signaling Molecule; Staging; Thiazolidinediones; Time; Transfection; Transgenic Mice; Transgenic Organisms; adipocyte differentiation; expression cloning; improved; in vivo; inhibitor/antagonist; insulin sensitivity; lipid biosynthesis; mouse model; receptor; resistin; sensor

DESCRIPTION (provided by applicant): ADSF/resistin is an adipocyte specific cysteine-rich secretory factor. ADSF is not expressed in preadipocytes but its expression increases late during adipocyte differentiation of 3T3-L1 and primary preadipocytes in culture. We found that addition of ADSF inhibits adipocyte differentiation in vitro. ADSF expression is undetectable in adipose tissue of fasted animals, but increases drastically upon refeeding. ADSF mRNA level is lower in genetic or diet-induced obesity mouse models. We, therefore, hypothesize that ADSF may be a sensor for energy status of animals and function as a feedback regulator of adipogenesis. At the same time, ADSF has been identified as a TZD suppressible gene that may be responsible for insulin resistance and was named resistin. We generated transgenic mice over expressing ADSF fused to human IgGgamma, heavy chain Fc region (hFc). We found that by binding to ADSF, ADSF-hFc functions in a dominant negative manner to attenuate ADSF inhibition of adipocyte differentiation in vitro. Furthermore, the ADSF-hFc overexpressing transgenic mice are obese but show improved insulin sensitivity. The goal of this research is to elucidate the molecular mechanisms underlying the antiadipogenic action of ADSF. We will determine the specific stages of adipocyte differentiation and mode of ADSF action. We will also elucidate downstream signaling of ADSF by examining signaling pathways shown to be critical for adipocyte differentiation, using various inhibitors and dominant negative or constitutively active molecules. Next, we will identify/clone the ADSF receptor that mediates ADSF inhibition of adipogenesis. First, we will demonstrate specific high affinity binding of ADSF to a cell surface protein. We will then clone the putative ADSF receptor via mammalian expression cloning by retrovirally expressing cDNAs and fluorescence activated cell sorting. Lastly, we will examine ADSF function in vivo by generating and examining ADSF-hFc and ADSF overexpressing transgenic mice. This research is directed toward understanding adipocyte differentiation, a critical process that contributes to the development of excess adipose mass and obesity. It is important to elucidate the mechanisms of ADSF function in order to develop strategies for controlling adipogenesis as well as treating type 2 diabetes by modifying ADSF action.

描述（由申请人提供）：ADSF/抵抗素是脂肪细胞特异性富含半胱氨酸的分泌因子。 ADSF在前脂肪细胞中未表达，但其表达在培养物中3T3-L1和原发性脂肪细胞的脂肪细胞分化过程中增加。我们发现，ADSF的添加在体外抑制脂肪细胞分化。在禁食动物的脂肪组织中，ADSF的表达是无法检测的，但在重新培养后会大大增加。 ADSF mRNA水平在遗传或饮食诱导的肥胖小鼠模型中较低。因此，我们假设ADSF可能是动物能量状态的传感器，并且起作用的反馈调节剂。同时，ADSF被确定为可能导致胰岛素耐药性并被命名为抵抗蛋白的TZD抑制基因。我们通过表达与人Igggamma（HFC）的人Igggamma（HFC）的ADSF生成了转基因小鼠。我们发现，通过与ADSF结合，ADSF-HFC以主要的负面方式功能减弱了ADSF在体外抑制脂肪细胞分化的抑制作用。此外，ADSF-HFC过表达的转基因小鼠肥胖，但表现出改善的胰岛素敏感性。 这项研究的目的是阐明ADSF的抗二脂作用的分子机制。我们将确定脂肪细胞分化和ADSF作用模式的特定阶段。我们还将使用各种抑制剂和主动性活性分子来检查对脂肪细胞分化至关重要的信号传导途径，从而阐明ADSF的下游信号传导。接下来，我们将识别/克隆介导ADSF抑制脂肪形成的ADSF受体。首先，我们将展示ADSF与细胞表面蛋白的特定高亲和力结合。然后，我们将通过逆转录病毒表达cDNA和荧光激活的细胞分选通过哺乳动物表达克隆来克隆推定的ADSF受体。最后，我们将通过生成和检查ADSF-HFC和ADSF过表达的转基因小鼠来检查体内ADSF功能。这项研究旨在理解脂肪细胞分化，这是一个关键过程，有助于发展过量的脂肪质量和肥胖。重要的是要阐明ADSF功能的机制，以制定控制脂肪形成以及通过修改ADSF作用来治疗2型糖尿病的策略。