title: DNA methylation and histone deacetylation regulating insulin sensitivity due to chronic cold exposure.
abstract: In this study, we investigated the causal relationship between chronic cold exposure and insulin resistance and the mechanisms of how DNA methylation and histone deacetylation regulate cold-reduced insulin resistance. 46 adult male mice from postnatal day 90-180 were randomly assigned to control group and cold-exposure group. Mice in cold-exposure group were placed at temperature from -1 to 4 °C for 30 days to mimic chronic cold environment. Then, fasting blood glucose, blood insulin level and insulin resistance index were measured with enzymatic methods. Immunofluorescent labeling was carried out to visualize the insulin receptor substrate 2 (IRS2), Obese receptor (Ob-R, a leptin receptor), voltage-dependent anion channel protein 1 (VDAC1), cytochrome C (cytC), 5-methylcytosine (5-mC) positive cells in hippocampal CA1 area. Furthermore, the expressions of some proteins mentioned above were detected with Western blot. The results showed: ① Chronic cold exposure could reduce the insulin resistance index (P < 0.01) and increase the number of IRS2 positive cells and Ob-R positive cells in hippocampus (P < 0.01). ② The expressions of mitochondrial energy-relative proteins, VDAC1 and cytC, were higher in cold-exposure group than in control group with both immunohistochemical staining and Western blot (P < 0.01). ③ Chronic cold exposure increased DNA methylation and histone deacetylation in the pyramidal cells of CA1 area and led to an increase in the expression of histone deacetylase 1 (HDAC1) and DNA methylation relative enzymes (P < 0.01). In conclusion, chronic cold exposure can improve insulin sensitivity, with the involvement of DNA methylation, histone deacetylation and the regulation of mitochondrial energy metabolism. These epigenetic modifications probably form the basic mechanism of cold-reduced insulin resistance.
authors.affiliation: Institute of Neurobiology, College of Life Science, Henan University, Kaifeng 475004, PR China; College of Nursing, Henan University, Kaifeng, 475004, Henan Province, PR China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Neurobiology, College of Life Science, Henan University, Kaifeng 475004, PR China.
authors.forename: Lai
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Neurobiology, College of Life Science, Henan University, Kaifeng 475004, PR China.
authors.forename: Yizheng
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Institute of Neurobiology, College of Life Science, Henan University, Kaifeng 475004, PR China.
authors.forename: Ruiping
authors.initials: R
authors.lastname: Li
authors.affiliation: Institute of Neurobiology, College of Life Science, Henan University, Kaifeng 475004, PR China. Electronic address: jinbo_deng@henu.edu.cn.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Deng
authors.affiliation: College of Nursing, Henan University, Kaifeng, 475004, Henan Province, PR China. Electronic address: dengjiexin@yahoo.com.
authors.forename: Jiexin
authors.initials: J
authors.lastname: Deng
mesh_terms: D044503:5-Methylcytosine / Q000378:metabolism; D000107:Acetylation; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D003080:Cold Temperature; D045304:Cytochromes c / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics*; D004734:Energy Metabolism / Q000502:physiology*; D044127:Epigenesis, Genetic; D006657:Histones / Q000378:metabolism*; D007328:Insulin / Q000097:blood / Q000378:metabolism; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D054411:Receptors, Leptin / Q000378:metabolism; D050995:Voltage-Dependent Anion Channel 1 / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D006657:Histones; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D054411:Receptors, Leptin; C494763:Vdac1 protein, mouse; D044503:5-Methylcytosine; D045304:Cytochromes c; D050995:Voltage-Dependent Anion Channel 1
keywords: Chronic cold exposure; DNA methylation; Histone deacetylation; Insulin resistance; Mitochondrion