All-Trans Retinoic Acid Induces CD4+CD25+FOXP3+ Regulatory T Cells by Increasing FOXP3 Demethylation in Systemic Sclerosis CD4+ T Cells

Figure 3

DNA methylation levels at the FOXP3 promoter in SSc CD4+ T cells. The average methylation level of the FOXP3 gene promoter sequence was cloned and sequenced as described in Materials and Methods. (a) The bar graph shows the mean DNA methylation status of the FOXP3 promoter in different groups. (b) The broken line shows the mean methylation status of 8 CG pairs in the promoter region of FOXP3 within 10 sequenced clones in different groups. The DNA methylation status of the FOXP3 promoter region was significantly decreased in SSc CD4+ T cells with the stimulation of the ATRA alone group or the ATRA and TGF-β combined group compared with negative controls (). The mean methylation level was not obviously different in the TGF-β alone group (). Moreover, no significant changes in the promoter methylation level of FOXP3 were observed in the ATRA alone group compared with the ATRA and TGF-β combined group. (). Data are presented as the mean ± SD and are representative of at least 3 independent experiments.

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