DOI: 10.2337/db07-0040
Cideb regulates diet-induced obesity, liver steatosis and insulin sensitivity by controlling lipogenesis and fatty acid oxidation
1Department of Biology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Correspondence: li-peng{at}mail.tsinghua.edu.cn
Key Words: Cideb obesity insulin sensitivity liver steatosis fatty acid oxidation lipogenesis SREBP1c ACC2 Our previous study suggests that Cidea, a member of Cide family proteins that share sequence homology with the DNA fragmentation factor and expressed at high levels in brown adipose tissue, plays an important role in the development of obesity. Cideb, another member of Cide family protein, is highly expressed in the liver. Objective:We would like to understand the physiological role of Cideb in the regulation of energy expenditure and lipid metabolism. Research design and Method:We generated Cideb-null mice by homologues recombination and then fed both wild type and Cideb-null mice with high-fat diet (58% fat). We then characterized the animals' adiposity index, food intake, whole body metabolic rate, liver morphology, rate of fatty acid synthesis and oxidation, insulin sensitivity and gene expression profile. Result:Cideb-null mice had lower levels of plasma triglycerides, free fatty acids, and are resistant to high-fat diet-induced obesity and live steatosis. In addition, Cideb mutant mice displayed significantly increased insulin sensitivity and enhanced rate of whole body metabolism and hepatic fatty acid oxidation. More importantly, Cideb-null mice showed decreased lipogenesis and reduced expression levels of acetyl-CoA carboxylase, fatty acid synthase and stearol-CoA desaturase. We further demonstrated that expression levels of sterol response element binding protein 1c (SREBP1c) was significantly decreased in Cideb deficient mice. Conclusion:Our data demonstrated that Cideb is a novel important regulator in lipid metabolism in the liver. Cideb may represent a new therapeutic target for the treatment of obesity, diabetes and liver steatosis.
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