Follistatin promotes browning and influences energy metabolism

描述（由申请人提供）：肥胖是一个主要的健康问题，在全世界以流行病的速度蔓延，没有任何减轻的迹象。肥胖症的发展通常与胰岛素抵抗和糖尿病有关，是由于能量摄入超过支出。棕色脂肪组织（BAT）具有燃烧多余热量的独特能力，并促进甘油三酯清除和葡萄糖处置。以前，我们确定卵泡抑素（Fst）作为睾酮的直接靶点，调节骨骼肌质量并抑制转化生长因子-β（TGF-β）信号传导。基于我们的初步发现，我们假设Fst通过调节Mst/TGF-β /BMP/Myf 5/PRDM 16信号通路促进整体产热程序并改善肥胖和代谢紊乱症状。我们将测试我们的假设与以下具体目标-目标1：我们将证明在棕色脂肪分化和产热程序在体外和体内的调节Fst的重要作用。目标二：我们将确定Fst调节整体产热程序的分子机制，目标3：我们将产生脂联素或UCP 1调节元件控制下表达Fst的小鼠，并将其代谢参数和对高脂饮食的反应与对照同窝仔进行比较。我们将在基础和β-肾上腺素受体激动剂（CL 316，248）刺激条件下，使用体外和体内模型，确定内源性和外源性Fst对关键产热标志物的蛋白质和基因表达谱以及总体细胞生物能量学的影响。将通过Affytron基因表达和定量蛋白质印迹分析来分析Myf 5/PRDM 16、Mst/pSmad 2/3/BMP/考克斯2、胰岛素受体和AMPK/PGC-1α信号通路在体外模型中以及在脂联素-Fst和UCP 1-Fst转基因小鼠中的参与。小鼠前脂肪细胞和MEF培养物中Fst、Myf 5和Smad 3的表达水平将被siRNA抑制，并测定其产热能力。我们将使用脂联素（Adipoq）和UCP 1特异性启动子产生Fst转基因小鼠，并在基础和β-肾上腺素受体激动剂（CL 316，248）刺激条件下测试高脂饮食对其身体组成（Micro CT）、能量消耗（间接量热分析）、胰岛素敏感性和葡萄糖耐量的影响。将通过ELISA法分析血清Fst、脂联素和血脂水平。评价Fst在其调节整个产热过程中的关键作用将为治疗肥胖和相关代谢疾病的新型治疗药物设计提供理论基础。

DESCRIPTION (provided by applicant): Obesity is a major health problem spreading at an epidemic pace throughout the world without any sign of abatement. Development of obesity, which is often associated with insulin resistance and diabetes, results from an excess of energy intake over expenditure. Brown adipose tissues (BAT) have the unique ability to burn excess calories, and facilitate triglyceride clearance and glucose disposal. Previously, we identified Follistatin (Fst) as a direct target of testosterone that regulates skeletal muscle mass and inhibits transforming growth factor-β (TGF-β) signaling. Based on our preliminary findings, we hypothesize that Fst promotes overall thermogenic program and improves symptoms of obesity and metabolic disorder by regulating overall Mst/TGF-β /BMP/Myf5/PRDM16- signaling pathways. We will test our hypothesis with the following Specific Aims- Aim 1: We will demonstrate the essential role of Fst during brown fat differentiation and the regulation of thermogenic program in vitro and in vivo. Aim 2: We will determine the molecular mechanisms by which Fst regulates the overall thermogenic program and Aim 3: We will generate mice expressing Fst under the control of adiponectin or UCP1 regulatory elements, and compare their metabolic parameters and response to high fat chow diet with control littermates. We will determine the effect of endogenous and exogenous Fst on protein and gene expression profiles of key thermogenic markers, and overall cellular bioenergetics using both in vitro and in vivo models under basal and β-adrenoceptor agonist (CL316,248) stimulated conditions. Involvement of Myf5/PRDM16, Mst/pSmad2/3/BMP/COX 2, insulin receptor and AMPK/PGC-1α signaling pathway in in vitro models as well as in adiponectin-Fst and UCP1-Fst transgenic mice will be analyzed by Affymetrix gene expression and quantitative western blot analysis. Expression levels of Fst, Myf5 and Smad3 in mouse preadipocytes and MEF cultures will be inhibited by siRNAs and their thermogenic capabilities will be determined. We will generate Fst-transgenic mice using adiponectin (Adipoq) and UCP1-specific promoters, and test the effect of high fat diet on their body composition (Micro CT), energy expenditure (indirect calorimetric analysis), insulin sensitivity and glucose tolerance under both basal and β-adrenoceptor agonist (CL 316,248) stimulated conditions. Serum levels of Fst, adiponectin and lipid profiles will be analyzed by ELISA. Evaluating the critical role of Fst during its regulation of overall thermogenic process will provide rationale for novel therapeutic drug design for the treatment of obesity and related metabolic diseases.