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Loss of Mbd2 protects mice against high fat diet-induced obesity and insulin resistance
by regulating the homeostasis of energy storage and expenditure
Jia Cheng,1,2,# Jia Song,1,# Xiaoyu He,1 Meng Zhang,1 Shuang Hu,1 Shu Zhang,1 Qilin Yu,1
Ping Yang,1 Fei Xiong,1 Dao Wen Wang,2 Jianfeng Zhou,3 Qin Ning,4 Zhishui Chen, 1 Decio L
Eizirik,5 Zhiguang Zhou,6 Chunxia Zhao, 2,* and Cong Yi Wang1,*
1The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of
Education, Key Laboratory of Organ Transplantation, Ministry of Health, 2The Institute of
Hypertension and Department of Internal Medicine, 3Department of Hematology,
4Department of Infectious Disease, Tongji Hospital, Tongji Medical College, Huazhong
University of Science and Technology, 1095 Jiefang Ave., Wuhan, 430030, China;
5Laboratory of Experimental Medicine, Universite Libre de Bruxelles, Route de Lennik 808,
CP 618, B 1070, Brussels, Belgium;
6Diabetes Center, the Second Xiangya Hospital, Institute of Metabolism and Endocrinology,
Central South University, Changsha, 410011, China.
# These authors contributed equally to this work.
*All correspondence should be addressed to Drs. Cong Yi Wang ([email protected]) or Chunxia Zhao ([email protected]).
Running title: MBD2 regulates High fat diet induced obesity and insulin resistance
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Diabetes Publish Ahead of Print, published online August 23, 2016 Page 3 of 117 Diabetes
Abstract
Previous studies including ours demonstrated that MBD2 acts as reader to decipher DNA
methylome encoded information. We thus in the present report employed Mbd2 / mice as a
model to dissect the impact of high fat diet (HFD) on DNA methylome relevant to the
pathoetiology of obesity. It was interestingly noted that mice deficient in Mbd2 were
protected from HFD induced obesity and insulin resistance. Mechanistic study revealed that
HFD rendered epididymal adipose tissues to undergo a DNA methylation turnover as
evidenced by the changes of methylation levels and patterns. Specifically, HFD was noted
with higher potency to induce DNA hypomethylation in genes relevant to energy storage than
that in genes associated with energy expenditure. As a result, arrays of genes were subjected
to expression changes, which led to an altered homeostasis for energy storage and expenditure
in favor of obesity development. Loss of Mbd2 resulted in impaired implementation of above
DNA methylation changes associated with altered energy homeostasis, which then protected
mice from HFD induced obesity and insulin resistance. Those data would provide novel
insight into the understanding of the pathoetiology underlying obesity with potential for
developing effective therapies against obesity in clinical settings.
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The ongoing obesity epidemic and its associated complications of chronic diseases such as type 2 diabetes, dyslipidemia, non alcoholic fatty liver disease (NAFLD) and hypertension, exert formidable challenges and burden to human health (1). Obesity is caused by a complex interplay between genetic and environmental factors. It is believed that environmental factors interact with susceptible genes to modulate the risk for obesity, which may also happen through direct chemical modifications of the genome by so called DNA methylation.
Although high fat diet (HFD), as a highly influential environmental factor, has long been employed to induce obesity and insulin resistance, its impact on epigenetic modifications of the genome, especially in the adipose genome, is yet to be fully elucidated. Evidence shows that short term of high fat overfeeding impacts genome wide DNA methylation patterns in human skeletal muscle (2). A global study of DNA methylation in human adipose tissue also characterized changes for the epigenetic patterns in response to long term exercise, potentially affecting adipocyte metabolism (3). Given that DNA methylation acts as a
“footprint” to record gene