01.31.07

Epigenetic Control of Regulatory T Cells

Posted in methylation, research articles at 12:55 am by Trevor

New research published this week in PLoS Biology shows the importance of epigenetic modifications in regulatory T cells.

Regulatory T cells play a pivotal role in the maintenance of self-tolerance within the immune system by preventing autoimmunity or excessive activation of the T cells that respond to pathogens (naïve and effector T cells). They differentiate within the thymus, but can also be de novo induced in the rest of the body. Mechanisms determining development of a stable regulatory T cell lineage are unknown. Our study provides evidence for a critical role of epigenetic modifications in the locus coding for the forkhead transcription factor Foxp3, which acts as a master switch controlling regulatory T cell development and function: An evolutionarily conserved region within the non-coding part of the gene contains CpG motifs, which are completely demethylated in regulatory T cells, but methylated in naïve and effector T cells, whereas we observed an inverse occurrence of acetylated histones, another epigenetic chromatin modification. Regulatory T cells induced in vitro—which, in contrast to natural regulatory T cells, do not display a stable regulatory T cell phenotype—display only incomplete DNA demethylation despite high Foxp3 expression. Our data suggest that expression of Foxp3 must be stabilized by epigenetic modification to result in a permanent suppressor cell lineage, a finding of significant importance for therapeutic applications involving induction or transfer of regulatory T cells and for the understanding of long-term cell lineage decisions.

Link