Development of a unique epigenetic signature during in vivo Th17 differentiation

Abstract

Activated naive CD4+ T cells are highly plastic cells that can differentiate into various T helper (Th) cell fates characterized by the expression of effector cytokines like IFN-γ (Th1), IL-4 (Th2) or IL-17A (Th17). Although previous studies have demonstrated that epigenetic mechanisms including DNA demethylation can stabilize effector cytokine expression, a comprehensive analysis of the changes in the DNA methylation pattern during differentiation of naive T cells into Th cell subsets is lacking. Hence, we here performed a genome-wide methylome analysis of ex vivo isolated naive CD4+ T cells, Th1 and Th17 cells. We could demonstrate that naive CD4+ T cells share more demethylated regions with Th17 cells when compared to Th1 cells, and that overall Th17 cells display the highest number of demethylated regions, findings which are in line with the previously reported plasticity of Th17 cells. We could identify seven regions located in Il17a, Zfp362, Ccr6, Acsbg1, Dpp4, Rora and Dclk1 showing pronounced demethylation selectively in ex vivo isolated Th17 cells when compared to other ex vivo isolated Th cell subsets and in vitro generated Th17 cells, suggesting that this unique epigenetic signature allows identifying and functionally characterizing in vivo generated Th17 cells.

De novo DNA methylation by DNA methyltransferase 3a controls early effector CD8 + T-cell fate decisions following activation

“…1F). Meanwhile, the endogenous host CD8 + gp [33][34][35][36][37][38][39][40][41] -specific T cells in recipient DNMT3a KO mice showed the consistent increase in the CD127 + KLRG1 − memory precursor cells and decrease in the CD127 − KLRG1 + terminal effector cell population seen in the absence of WT P14 adoptive transfer (Fig. 1F).…”

“…Mice were infected with virus and immunodominant CD8 + T-cell responses were assessed by MHC I viral epitope-tetramer staining: H-2K b -restricted Ova 257-264 , H-2D b -restricted influenza nucleoprotein [366][367][368][369][370][371][372][373][374] , and H-2D brestricted LCMV gp [33][34][35][36][37][38][39][40][41] . At the peak of the CD8 + T-cell response to each type of infection (VacOva = day 7, influenza and LCMV = day 10), no significant differences in the absolute numbers of CD8 + -tetramer + cells were noted between WT and DNMT3a KO mice ( Fig.…”

“…1E). Conversely, when WT P14 TCR-Tg cells (specific to LCMV gp [33][34][35][36][37][38][39][40][41] ) were transferred into a WT or DNTM3a KO host, the P14 effector/memory precursor balance developed normally (Fig. 1F).…”

“…LCMV-infected WT and DNMT3a KO mice were assessed for their CD8 + T-cell memory response 60 d after infection. Indeed, DNMT3a KO mice had increased numbers of gp [33][34][35][36][37][38][39][40][41] -specific CD8 + T cells compared with WT mice as assessed by tetramer staining ( Fig. 2A) and cytokine secretion (Fig.…”

Vitamin C Facilitates Demethylation of the Foxp3 Enhancer in a Tet-Dependent Manner

“…1C), suggesting that vitamin C works in a dosedependent manner, and its effect reaches a plateau in 10 mg/ml. To exclude the possibility that vitamin C works nonspecifically, like 5-azacytidine (23), we checked the methylation status of other Treg signature genes such as Tnfrsf18 (Gitr), Ctla4, Ikzf4 (Eos), Cd25 (14), and Il17a (a negative control) (47). We found that vitamin C works specifically in the Foxp3 CNS2 region (Fig.…”