Stimulated by Retinoic Acid (STra6) in Energy Homeostasis

描述(由申请人提供)： 本申请旨在促进申请者的培训和职业发展，其目标是成为一名独立调查员。拟议的研究为申请者提供了广泛的细胞生物学和生物化学技术，使申请者能够发展糖尿病研究方面的专业知识。职业发展计划包括一个具有潜在临床应用的引人注目的研究项目，实验室技术培训，以及教学科学研讨会。2型糖尿病的特征是肌肉、肝脏和脂肪组织等组织的胰岛素作用受损。长期目标是确定胰岛素抵抗和糖尿病的发病机制。视黄醇结合蛋白4(RBP4)在啮齿动物和患有肥胖和胰岛素抵抗的人类中升高。在啮齿动物体内注射纯化的RBP4会导致胰岛素抵抗、糖耐量异常和骨骼肌胰岛素信号转导受损。新近发现STRA6(受维甲酸刺激)是RBP4的高亲和力受体。这笔赠款将利用细胞培养研究、原始组织外植体和活体模型来检验RBP4导致胰岛素抵抗的假设，部分原因是它与STRA6在脂肪组织和骨骼肌等组织中的相互作用。在具体目标#1中，将在培养的心肌细胞中确定RBP4-STRA6相互作用在葡萄糖代谢和胰岛素信号转导中的重要性，申请者将研究RBP4-STRA6途径改变葡萄糖稳态的机制。目的#2将确定STRA6是否介导了RBP4诱导的骨骼肌胰岛素抵抗。这将通过测定骨骼肌特异的STRA6基因敲除小鼠的葡萄糖稳态，以及通过测量分离肌肉中的葡萄糖摄取和胰岛素信号来实现。目的#3将确定脂肪组织中RBP4-STRA6的相互作用是否会改变全身的血糖稳态和肥胖的发展。将在接受STRA6反义寡核苷酸治疗的小鼠和脂肪组织STRA6基因敲除小鼠中研究葡萄糖代谢、胰岛素敏感性、身体组成和能量消耗。由于STRA6介导了细胞对视黄醇的摄取，因此将测定血清和组织中视黄醇和维甲酸的水平。 公共卫生相关性：拟议的实验将有助于更好地理解胰岛素抵抗和2型糖尿病的发病机制。治疗胰岛素抵抗的新靶点可以设计成针对维甲酸-RBP4-STRA6通路。

DESCRIPTION (provided by applicant): This application is designed to facilitate the training and career development of the applicant, whose goal is to be an independent investigator. The proposed studies provide the applicant with a wide range of cell biology and biochemistry techniques to allow the applicant to develop expertise in diabetes research. The career development plan includes a compelling research project with potential clinical applications, laboratory technique training, and didactic scientific seminars. Type 2 diabetes is characterized by impaired insulin action in tissues such as muscle, liver, and adipose tissue. The long term objective is to determine the mechanisms involved in the pathogenesis of insulin resistance and diabetes. Retinol binding protein 4 (RBP4) is elevated in rodents and humans with obesity and insulin resistance. Injection of purified RBP4 in rodents causes insulin resistance, glucose intolerance, and impaired insulin signaling in skeletal muscle. STRA6 (Stimulated by retinoic acid) was recently identified as a high affinity receptor for RBP4. This grant will test the hypothesis that RBP4 causes insulin resistance in part through its interactions with STRA6 in tissues such as adipose tissue and skeletal muscle utilizing cell culture studies, primary tissue explants, and in vivo models. In specific aim #1, the importance of RBP4-STRA6 interactions in glucose metabolism and insulin signaling will be determined in cultured myocytes, and the applicant will investigate the mechanisms by which the RBP4-STRA6 pathway alters glucose homeostasis. Aim #2 will determine if STRA6 mediates RBP4-induced insulin resistance in skeletal muscle. This will be accomplished by determining glucose homeostasis in the skeletal muscle specific STRA6 knockout mouse and by measuring glucose uptake and insulin signaling in isolated muscle. Aim #3 will determine if RBP4-STRA6 interactions in adipose tissue alter whole body glucose homeostasis and the development of obesity. Glucose metabolism, insulin sensitivity, body composition, and energy expenditure will be studied in mice treated with STRA6 antisense oligonucleotides and in the adipose tissue STRA6 knockout mouse. Since STRA6 mediates the cellular uptake of retinol, serum and tissue levels of retinoids such as retinol and retinoic acid will be determined. PUBLIC HEALTH RELEVANCE: The proposed experiments will lead to a better understanding of mechanisms involved in the pathogenesis of insulin resistance and type 2 diabetes. New therapeutic targets to treat insulin resistance could be designed to target the retinoid-RBP4-STRA6 pathway.