title: Vitamin C Facilitates Demethylation of the Foxp3 Enhancer in a Tet-Dependent Manner.
abstract: Demethylation of CpG motifs in the Foxp3 intronic element, conserved noncoding sequence 2 (CNS2), is indispensable for the stable expression of Foxp3 in regulatory T cells (Tregs). In this study, we found that vitamin C induces CNS2 demethylation in Tregs in a ten-eleven-translocation 2 (Tet2)-dependent manner. The CpG motifs of CNS2 in Tregs generated in vitro by TGF-β (iTregs), which were methylated originally, became demethylated after vitamin C treatment. The conversion of 5-methylcytosin into 5-hydroxymethylcytosin was more efficient, and the methyl group from the CpG motifs of Foxp3 CNS2 was erased rapidly in iTregs treated with vitamin C. The effect of vitamin C disappeared in Tet2(-/-) iTregs. Furthermore, CNS2 in peripheral Tregs in vivo, which were demethylated originally, became methylated after treatment with a sodium-dependent vitamin C transporter inhibitor, sulfinpyrazone. Finally, CNS2 demethylation in thymic Tregs was also impaired in Tet2(-/-) mice, but not in wild type mice, when they were treated with sulfinpyrazone. Collectively, vitamin C was required for the CNS2 demethylation mediated by Tet proteins, which was essential for Foxp3 expression. Our findings indicate that environmental factors, such as nutrients, could bring about changes in immune homeostasis through epigenetic mechanisms.
authors.affiliation: Department of Pathology, Hallym University College of Medicine, Chuncheon, Gangwon-Do 200-702, Korea.
authors.forename: Varun
authors.initials: V
authors.lastname: Sasidharan Nair
authors.affiliation: Department of Pathology, Hallym University College of Medicine, Chuncheon, Gangwon-Do 200-702, Korea.
authors.forename: Mi Hye
authors.initials: MH
authors.lastname: Song
authors.affiliation: Department of Pathology, Hallym University College of Medicine, Chuncheon, Gangwon-Do 200-702, Korea kwonik@hallym.ac.kr.
authors.forename: Kwon Ik
authors.initials: KI
authors.lastname: Oh
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002469:Cell Separation; D018899:CpG Islands / Q000235:genetics / Q000276:immunology; D019175:DNA Methylation / Q000187:drug effects*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000276:immunology; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000276:immunology; D047468:Immunoprecipitation; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000276:immunology*; D014162:Transfection
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; C062255:Tet DNA polymerase; D004259:DNA-Directed DNA Polymerase; D001205:Ascorbic Acid