DNA methylation controls Foxp3 gene expression.
Compelling evidence suggests that Foxp3-expressing CD25(+)CD4(+) regulatory T cells (Treg) are generated within the thymus as a separate lineage. However, Foxp3(+)CD4(+) Treg can also be generated de novo in a TGF-beta-dependent process from naive T cells by TCR triggering. Recently, we have shown that naturally occurring, but not in vitro TGF-beta-induced Foxp3(+) Treg display stable Foxp3 expression that was associated with selective demethylation of an evolutionarily conserved element within the Foxp3 locus named TSDR (Treg-specific demethylated region). Here, we report that inhibition of DNA methylation by azacytidine, even in absence of exogenous TGF-beta, not only promoted de novo induction of Foxp3 expression during priming, but also conferred stability of Foxp3 expression upon restimulation. Most notably, such stable Foxp3 expression was found only for cells displaying enhanced TSDR demethylation. In contrast, in vitro TSDR methylation diminished its transcriptional activity. Foxp3(+) Treg generated in vivo by DEC-205-mediated targeting of agonist ligands to dendritic cells showed long-term survival in the absence of the inducing antigen and exhibited efficient TSDR demethylation. Together, our data suggest that TSDR is an important methylation-sensitive element regulating Foxp3 expression and demonstrate that epigenetic imprinting in this region is critical for establishment of a stable Treg lineage.
Polansky
Julia K
JK
Experimentelle Rheumatologie/Experimentelle Immunregulation, Charité Universitaetsmedizin Berlin, Berlin, Germany.
Kretschmer
Karsten
K
Freyer
Jennifer
J
Floess
Stefan
S
Garbe
Annette
A
Baron
Udo
U
Olek
Sven
S
Hamann
Alf
A
von Boehmer
Harald
H
Huehn
Jochen
J
D019264:Adoptive Transfer; D000818:Animals; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000637:transplantation; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; C499308:Rag2 protein, mouse; D011948:Receptors, Antigen, T-Cell; D016212:Transforming Growth Factor beta; D000077209:Decitabine; D010047:Ovalbumin; D001374:Azacitidine