title: FOXP3 demethylation as a means of identifying quantitative defects in regulatory T cells in acute coronary syndrome.
abstract: OBJECTIVE
  The contribution of regulatory T cells (Tregs) to the pathogenesis of acute coronary syndrome (ACS) remains poorly understood. One core obstacle is the lack of Treg-specific markers. A highly conserved CpG enriched element in forkhead box P3 intron 1 (FOXP3 i l) is unmethylated only in Tregs, and measuring the unmethylation of FOXP3 i l can be used to identify the role of Tregs in clinical diseases. This study investigated whether analyzing the demethylation status of FOXP3 i 1 is a more reliable means than using Treg-specific surface markers in ACS.
  
  
  RESULTS
  We evaluated circulating Tregs percentages on different levels including cell frequencies (CD4(+)CD25(hi)FOXP3(+)Tregs and CD4(+)CD25(hi)CD45(+)naïve Tregs) or FOXP3 mRNA, FOXP3 i 1 demethylation status and related cytokine secretion in 89 patients with ACS and 35 controls. FOXP3 i 1 demethylation assay showed that the amount of Tregs in ACS patients was significantly reduced than that in controls (p = 0.0005). However, flow cytometry analysis did not identify any reduction of CD4(+)CD25(hi)FOXP3(+)Tregs in ACS patients. Notably, younger patients had higher percentage of CD4(+)CD25(hi)FOXP3(+)Tregs but decreased percentage of CD4(+)CD25(hi)CD45(+)naïve Tregs than either controls or older patients. Furthermore, a DNA hypomethylation agent increased the amount of CD4(+)CD25(hi)FOXP3(+)Tregs and Tregs related cytokine IL-10 and suppressed the production of pro-inflammatory cytokine interferon-γ by inducing FOXP3 i 1 demethylation in vitro.
  
  
  CONCLUSIONS
  A quantitative defect of Tregs, suggestive of decreased peripheral tolerance, could be a potential hallmark of ACS disease. Targeting FOXP3 i l demethylation might elevate the inhibitory activity of Tregs in ACS.
authors.affiliation: Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. lvcaixia@126.com
authors.forename: Cai-Xia
authors.initials: CX
authors.lastname: Lü
authors.forename: Ren-De
authors.initials: RD
authors.lastname: Xu
authors.forename: Ming
authors.initials: M
authors.lastname: Cao
authors.forename: Guan
authors.initials: G
authors.lastname: Wang
authors.forename: Feng-Qin
authors.initials: FQ
authors.lastname: Yan
authors.forename: Sha-Sha
authors.initials: SS
authors.lastname: Shang
authors.forename: Xiao-Fen
authors.initials: XF
authors.lastname: Wu
authors.forename: Lei
authors.initials: L
authors.lastname: Ruan
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Quan
authors.forename: Cun-Tai
authors.initials: CT
authors.lastname: Zhang
mesh_terms: D054058:Acute Coronary Syndrome / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism*; D000328:Adult; D000368:Aged; D050197:Atherosclerosis / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D015415:Biomarkers / Q000378:metabolism; D015704:CD4 Antigens / Q000378:metabolism; D002478:Cells, Cultured; D008078:Cholesterol, LDL / Q000097:blood; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors; D000077209:Decitabine; D015536:Down-Regulation / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology* / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000097:blood; D016753:Interleukin-10 / Q000097:blood; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008297:Male; D008745:Methylation / Q000187:drug effects; D008875:Middle Aged; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000097:blood; D019210:Troponin I / Q000097:blood; D015854:Up-Regulation / Q000276:immunology
chemical_list: D015415:Biomarkers; D015704:CD4 Antigens; D008078:Cholesterol, LDL; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508609:IL10 protein, human; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D053773:Transforming Growth Factor beta1; D019210:Troponin I; D016753:Interleukin-10; D000077209:Decitabine; D007371:Interferon-gamma; D015254:DNA Modification Methylases; D001374:Azacitidine