Epigenetically Mediated Pathogenic Effects of Phenanthrene on Regulatory T Cells

Figure 2

Phenanthrene exposure irreversibly impairs Treg function. (a) Isolated Treg from individual healthy donors (𝑛=5) were incubated with 300 nM Phe (black bars) or diluent (grey bars) for 0 to 7 days and analyzed for function using standard Treg suppression assays. (b) Teff proliferation was analyzed in Phe or diluent treated cultures of isolated Teff without Treg. To test the irreversibility of effects of Phe on Treg, Treg cultures were treated with Phe (c) or Phe+TGFβ (d) on day 0, followed by a wash and replacement with Phe-free media (+/−TGFβ) on either day 1 (24 h), 3, 4, or 7. CpG methylation of the FOXP3 locus (𝑛=13 CpG sites, 6 in promoter region, 7 in intronic region) (black bars), Treg phenotype (white bars), and Treg function (grey bars) of cultured Treg were assessed on day 7. ^∗𝑃<0.05; data represents mean +/− SD.

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