Regulation of the NFAT pathway discriminates CD4+CD25+ regulatory T cells from CD4+CD25- helper T cells.
CD4(+)CD25(+) regulatory T cells (Tregs) are potent modulators of immune responses. The transcriptional program distinguishing Tregs from the CD4(+)CD25(-) Th cells is unclear. NFAT, a key transcription factor, is reported to interact with forkhead box p3, allowing inhibitory and activating signals in T cells. In the current study, we hypothesize that distinctive NFAT regulation in Tregs as compared with Th cells, may contribute to specific functions of these cells. Tregs express basal levels of cytoplasmic NFATc1 and NFATc2. In contrast to Th cells, anti-CD3-mediated T cell activation did not induce nuclear translocation of NFATc1 or NFATc2 in Tregs. This effect was associated with altered regulation for NFAT in Tregs that included reduced calcium flux, diminished calcineurin activation, and increased activity of glycogen synthase kinase-3beta, a negative regulatory kinase for NFAT in Tregs relative to Th cells. These data suggested that NFAT inhibition in Th cells may induce regulatory function. Indeed, pharmacologically mediated NFAT inhibition induced Th cells to function as Tregs, an effect that was mediated by induction of membrane-bound TGF-beta on Th cells. Collectively, these data suggest that maintaining NFAT at basal levels is a part of the transcriptional program required for Tregs.
Sumpter
Tina L
TL
Department of Microbiology and Immunology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
Payne
Kyle K
KK
Wilkes
David S
DS
D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology*; D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000502:physiology; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D038362:Glycogen Synthase Kinase 3 / Q000502:physiology; D000071679:Glycogen Synthase Kinase 3 beta; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology*; D008213:Lymphocyte Activation; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D051379:Mice; D050778:NFATC Transcription Factors / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000502:physiology
D015703:Antigens, CD; D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit; D050778:NFATC Transcription Factors; C494005:Nfatc1 protein, mouse; C494007:Nfatc2 protein, mouse; D016212:Transforming Growth Factor beta; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3; D048670:MAP Kinase Kinase 4; D019703:Calcineurin; D002118:Calcium