title: A novel upstream enhancer of FOXP3, sensitive to methylation-induced silencing, exhibits dysregulated methylation in rheumatoid arthritis Treg cells.
abstract: Treg-cell function is compromised in rheumatoid arthritis (RA). As the master regulator of Treg cells, FOXP3 controls development and suppressive function. Stable Treg-cell FOXP3 expression is epigenetically regulated; constitutive expression requires a demethylated Treg-specific demethylated region. Here, we hypothesised that methylation of the FOXP3 locus is altered in Treg cells of established RA patients. Methylation analysis of key regulatory regions in the FOXP3 locus was performed on Treg cells from RA patients and healthy controls. The FOXP3 Treg-specific demethylated region and proximal promoter displayed comparable methylation profiles in RA and healthy-donor Treg cells. We identified a novel differentially methylated region (DMR) upstream of the FOXP3 promoter, with enhancer activity sensitive to methylation-induced silencing. In RA Treg cells we observed significantly reduced DMR methylation and lower DNA methyltransferase (DNMT1/3A) expression compared with healthy Treg cells. Furthermore, DMR methylation negatively correlated with FOXP3 mRNA expression, and Treg cells isolated from rheumatoid factor negative RA patients were found to express significantly higher levels of FOXP3 than Treg cells from RhF-positive patients, with an associated decrease in DMR methylation. In conclusion, the novel DMR is involved in the regulation of Treg-cell FOXP3 expression, but this regulation is lost post-transcriptionally in RA Treg cells.
authors.affiliation: Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom.
authors.forename: Alan
authors.initials: A
authors.lastname: Kennedy
authors.forename: Emily M
authors.initials: EM
authors.lastname: Schmidt
authors.forename: Adam P
authors.initials: AP
authors.lastname: Cribbs
authors.forename: Henry
authors.initials: H
authors.lastname: Penn
authors.forename: Parisa
authors.initials: P
authors.lastname: Amjadi
authors.forename: Khaja
authors.initials: K
authors.lastname: Syed
authors.forename: Jordan E
authors.initials: JE
authors.lastname: Read
authors.forename: Patricia
authors.initials: P
authors.lastname: Green
authors.forename: Bernard
authors.initials: B
authors.lastname: Gregory
authors.forename: Fionula M
authors.initials: FM
authors.lastname: Brennan
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000276:immunology*; D019175:DNA Methylation / Q000235:genetics / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000235:genetics* / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors
keywords: DNA methylation; Foxp3; Regulatory T cells; Rheumatoid arthritis