Functional aspects of SREBP1c in intact skeletal muscle

描述（由申请人提供）：MacLean博士在肌肉生理学，脂质代谢和骨骼肌基因表达调控方面受过培训。该建议包括教学培训、研究技能发展和指导研究项目，这将促进他发展成为一名独立的学术科学家。本研究计划重点研究腺病毒基因传递的体内模型对骨骼肌脂质代谢的调节。在肝脏、乳腺和脂肪组织中，有证据表明，甾醇反应元件结合蛋白（SREBPs），一个转录因子家族，介导胆固醇、甘油三酯和碳水化合物代谢相关基因表达的营养调节。一种特殊的异构体，SREBP1c，被认为与调节基因表达的方式有关，从而促进促进脂质积累的酶谱。由于这种与脂质积累的联系，人们假设SREBP1c的失调可能导致代谢综合征组织中常见的脂质异常。SREBP1c也在骨骼肌中表达，但其在骨骼肌中的调节和功能尚未阐明。该指导研究项目的工作将进一步描述一种新的体内方法来研究骨骼肌中的基因功能，并利用它来检测该组织中SREBP1c的基因靶点和生理作用。首先，腺病毒基因传递到骨骼肌的模型将在转导的即时性和持续时间、转导效果的滴度要求以及伴随的免疫反应的时间过程方面进行表征。其次，包含SREBP1c显性阳性或显性抑制形式表达盒的腺病毒载体将与模型一起使用，以鉴定对SREBP1c调控敏感的基因。第三，将与模型一起使用相同的腺病毒载体来检测SREBP1c对肌肉脂质代谢的影响。更好地了解骨骼肌中表达的基因的功能和相互作用可能会导致肌肉相关疾病的新治疗策略。该奖项将提供：1)将新技术应用于他的研究项目的手段；2)与成熟、成功的调查人员进行互动的正式计划；3)在一个良好的研究环境中，他有机会成熟自己的研究、教学和管理技能。

DESCRIPTION (provided by applicant): Dr. MacLean has trained in the areas of muscle physiology, lipid metabolism, and the regulation of gene expression in skeletal muscle. This proposal includes didactic training, research skill development, and a mentored research project, that will foster his development into an independent academic scientist. The research plan is focused on studying the regulation of skeletal muscle lipid metabolism in an in vivo model of adenoviral gene delivery. In the liver, mammary, and adipose tissue, there is evidence to suggest that sterol response element binding proteins (SREBPs), a family of transcription factors, mediate the nutritional regulation of the expression of genes involved in cholesterol, triglycerides, and carbohydrate metabolism. One particular isoform, SREBP1c, has been implicated in regulating gene expression in such a manner as to promote an enzymatic profile that would promote the accumulation of lipids. Because of this link to lipid accumulation, it has been hypothesized that the dysregulation of SREBP1c may be contributing to the lipid abnormalities commonly found with tissues in the metabolic syndrome. SREBP1c is also expressed in skeletal muscle, but its regulation and function in this tissue have not been elucidated. The work in the mentored research project will further characterize a novel in vivo approach to study gene function in skeletal muscle and employ it to examine the gene targets and physiological effects of SREBP1c in this tissue. First, a model of adenoviral gene delivery to skeletal muscle will be characterized with respect to the immediacy and duration of transduction, the titer requirements for transduction efficacy, and the time course of the accompanying immune response. Second, adenoviral vectors containing expression cassettes for the dominant positive or dominant inhibitory forms of SREBP1c will be used with the model to identify the genes that are sensitive to SREBP1c regulation. Third, the same adenoviral vectors will be used with the model to examine the effects of SREBP1c on muscle lipid metabolism. Having a better understanding of the function and interaction of genes expressed in skeletal muscle may lead to novel therapeutic strategies of muscle-related diseases. This award will provide: 1) the means to apply new techniques to his research program; 2) a formal plan for interaction with well-established, successful investigators; and 3) an opportunity for him to mature his research, teaching, and administrative skills, in an excellent research environment.