title: Folate supplementation modifies CCAAT/enhancer-binding protein α methylation to mediate differentiation of preadipocytes in chickens.
abstract: Folate, an essential vitamin participating in 1-carbon metabolism leading to a methyl donor function, is a key factor inducing epigenetic changes. This study sought to determine if folate influences the methylation level of cytosine-guanine (CpG) islands in the promoters of critical adipogenic genes in chickens, and how this might affect gene expression and differentiation of preadipocytes in vitro. Preadipocytes were treated with 0 to 16 mg/L of folate during the induction of differentiation, and cell proliferation and lipid accumulation were assessed. The folate supplementation resulted in enhanced cell proliferation and decreased content of lipid per adipocyte at d 6 of differentiation. The effects of folate on relative expression of genes critical for adipocyte differentiation and 1-carbon metabolism were measured by quantitative reverse-transcription PCR. Folate caused a dose-dependent decrease in transcript abundance of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα) gene expression, and the downstream enzyme fatty acid synthase; in contrast, expression of DNA (cytosine-5)-methyltransferase and methylenetetrahydrofolate reductase was obviously upregulated at d 6 of differentiation (P < 0.05). The DNA methylation was examined with the bisulfite sequencing PCR method. Overall CpG methylation in the C/EBPα gene promoter region was 21.8% lower (P < 0.05) and the gene's expression was 2.7-fold higher in the absence of folate, compared with cells treated with 16 mg/L of folate, whereas methylation of the PPARγ promoter was not affected. Overall, the results show that folate increased the proliferation of adipocytes but reduced per-cell lipid accumulation, thereby influencing differentiation; it increased expression of genes involved in 1-carbon metabolism resulting in greater methylation of the C/EBPα promoter during differentiation and decreased that gene's expression, perhaps accounting for decreased expression of PPARγ.
authors.affiliation: Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. ChinaState Key Laboratory of Animal Nutrition, Beijing 100193, P.R. China.
authors.forename: Xiaoqiong
authors.initials: X
authors.lastname: Yu
authors.affiliation: Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. ChinaState Key Laboratory of Animal Nutrition, Beijing 100193, P.R. China.
authors.forename: Ranran
authors.initials: R
authors.lastname: Liu
authors.affiliation: Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. ChinaState Key Laboratory of Animal Nutrition, Beijing 100193, P.R. China.
authors.forename: Guiping
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. ChinaState Key Laboratory of Animal Nutrition, Beijing 100193, P.R. China.
authors.forename: Maiqing
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. ChinaState Key Laboratory of Animal Nutrition, Beijing 100193, P.R. China.
authors.forename: Jilan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. ChinaState Key Laboratory of Animal Nutrition, Beijing 100193, P.R. China wenjie@caas.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Wen
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000187:drug effects*; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D030161:Avian Proteins / Q000235:genetics* / Q000378:metabolism; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D002645:Chickens / Q000235:genetics / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements / Q000032:analysis; D054890:Fatty Acid Synthase, Type I / Q000235:genetics / Q000378:metabolism; D005260:Female; D005492:Folic Acid / Q000494:pharmacology*; D008745:Methylation; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D030161:Avian Proteins; D022763:CCAAT-Enhancer-Binding Protein-alpha; D047495:PPAR gamma; D005492:Folic Acid; D054890:Fatty Acid Synthase, Type I
keywords: DNA methylation; adipocyte; chicken; folate; mRNA expression