Three novel acetylation sites in the Foxp3 transcription factor regulate the suppressive activity of regulatory T cells.

Publication Type:

Featured

Source:

Journal of immunology (Baltimore, Md. : 1950), Volume 188, Issue 6, p.2712-21 (2012)

Keywords:

Acetylationdigestive disease, digestive deseases Adoptive Transferdigestive disease, digestive deseases Amino Acid Sequencedigestive disease, digestive deseases Animalsdigestive disease, digestive deseases Blotting, Westerndigestive disease, digestive deseases Cell Differentiationdigestive disease, digestive deseases Forkhead Transcription Factorsdigestive disease, digestive deseases Humansdigestive disease, digestive deseases Immune Tolerancedigestive disease, digestive deseases Immunoprecipitationdigestive disease, digestive deseases Jurkat Cellsdigestive disease, digestive deseases Mass Spectrometrydigestive disease, digestive deseases Micedigestive disease, digestive deseases Molecular Sequence Datadigestive disease, digestive deseases Reverse Transcriptase Polymerase Chain Reactiondigestive disease, digestive deseases RNA, Messengerdigestive disease, digestive deseases T-Lymphocytes, Regulatorydigestive disease, digestive deseases Transfection

Abstract:

The Foxp3 transcription factor is the master regulator of regulatory T cell (Treg) differentiation and function. Its activity is regulated by reversible acetylation. Using mass spectrometry of immunoprecipitated proteins, we identify three novel acetylation sites in murine Foxp3 (K31, K262, and K267) and the corresponding sites in human FOXP3 proteins. Newly raised modification-specific Abs against acetylated K31 and K267 confirm acetylation of these residues in murine Tregs. Mutant Foxp3 proteins carrying arginine substitutions at the three acetylation sites (3KR) accumulate in T cells to higher levels than wild-type Foxp3 and exert better suppressive activity in coculture experiments. Acetylation and stability of wild-type, but not mutant, Foxp3 is enhanced when cells are treated with Ex-527, an inhibitor of the NAD(+)-dependent deacetylase SIRT1. Treatment with Ex-527 promotes Foxp3 expression during induced Treg differentiation, enhances Foxp3 levels in natural Tregs, and prevents loss of Foxp3 expression in adoptively transferred Tregs in mice. Our data identify SIRT1 as a negative regulator of Treg function via deacetylation of three novel target sites in Foxp3. SIRT1 inhibitors strengthen the suppressive activity of Tregs and may be useful in enhancing Treg-based therapeutic approaches to autoimmune diseases or graft rejections.