褐色脂肪组织在调控能量代谢中起重要作用。本课题组前期研究表明NAG-1转基因小鼠显著抵抗肥胖并提高脂肪燃烧和产热，预示NAG-1 可能是一个调节能量代谢和抑制肥胖的重要细胞因子。本项目拟采用BMP7为阳性对照，通过转染NAG-1脂质体或重组NAG-1蛋白来诱导脂肪前细胞3T3-L1与脂肪组织SVF细胞分化与褐化；分别从细胞形态变化、脂肪特异性基因/蛋白表达、线粒体生化合成、脂肪裂解和能量消耗等方面的研究来阐明NAG-1在调控脂肪分化、褐化以及能量代谢方面的作用；同时通过注射将NAG-1脂质体转染并诱导分化或褐化的3T3-L1或SVF 细胞到高脂饲料喂养的小鼠皮下组织来进一步研究NAG-1在调控褐色脂肪生成、能量消耗以及抵抗肥胖的作用与机制；用NAG-1基因敲除小鼠来验证NAG-1是一个新型褐色脂肪分化与能量代谢的重要调控因子。本研究将为利用褐色脂肪治疗肥胖及其引发的慢性疾病提供新靶向。

Brown adipose tissue plays an important role in thermogenesis and energy expenditure. Previously, we have shown that NAG-1 transgenic mice significantly inhibited obesity and improved thermogenesis and energy expenditure, suggesting NAG-1 might be an important factor to control energy expenditure and obesity. We will study brown fat differentiation and white fat browning to determine the regulatory effects of NAG-1 on energy expenditure. Using BMP-7 as positive control, pre-adipocyte 3T3-L1 and Stromal Vescular Factor (SVF) cells will be transfected with NAG-1 plasmid or treated with recombinant NAG-1 protein for the induction of brown adipocyte differentiation from 3T3-L1 or SVF cell browning. We will evaluate the effects of NAG-1 on brown adipocyte differentiation and/or white adipocyte browning through the observation of cell morphology change, measurement of the expression of key genes for brown and/or white adipose tissue, mitochondrial biogenesis, adipose lipolysis and energy expenditure. We will then inject the 3T3-L1 or SVF cells transfected with NAG-1 subcutaneously to high fat diet-fed mice to determine brown fat pad formation and energy expenditure in the mice. The NAG-1 knockout mice will be studied to determined whether depletion of NAG-1 could have an impact on brown and white adipose tissue formation and thus on weight and energy expenditure. Our study will provide new therapeutic target of using brown fat for the prevention obesity and related diseases.