IL-4 and prostaglandin E2 inhibit hypomethylation of the 5' regulatory region of IFN-gamma gene during differentiation of naive CD4+ T cells.
We have previously shown that prostaglandin E2 (PGE2) and IL-4 inhibit the priming of IFN-gamma-production during the differentiation of naive CD4+ T cells from human cord blood by different signal-transducing mechanisms. To compare and analyse the molecular mechanisms by which PGE2 and IL-4 inhibit the priming of IFN-gamma production, we investigated the effects of PGE2 and IL-4 on the methylation of the IFN-gamma gene during the in vitro differentiation of naive CD4+ T cells. In human naive CD4+ T cells, which produce primarily IL-2 and a little amount of IFN-gamma, the IFN-gamma gene was methylated. After stimulation via TCR, CD4+ T cells produced IFN-gamma and the CpG dinucleotide contained within the TATA proximal regulatory element of the IFN-gamma gene was partially hypomethylated. Both IL-4 and PGE2 inhibited the hypomethylation of this site and the acquisition of IFN-gamma-producing ability. In contrast to the SnaBI site in the TATA proximal regulatory element, the HpalI site in the first intron of the IFN-gamma gene of the CD4+ T cells from cord blood was completely methylated even after stimulation via TCR. 5-azacytidine restored the IFN-gamma-producing ability of these cells treated with IL-4 and PGE2. These findings suggest that, although the signal transduction that inhibits the priming of IFN-gamma-production is different for each reagent, the protection from hypomethylation of the regulatory region of the IFN-gamma gene is involved in the molecular mechanisms by which these reagents inhibit the priming of IFN-gamma-production during the differentiation of human naive CD4+ T cells.
Katamura
K
K
Department of Pediatrics, Faculty of Medicine, Kyoto University, Japan.
Fukui
T
T
Kiyomasu
T
T
Iio
J
J
Tai
G
G
Ueno
H
H
Heike
T
T
Mayumi
M
M
Furusho
K
K
D001374:Azacitidine / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D019175:DNA Methylation / Q000187:drug effects*; D015232:Dinoprostone / Q000494:pharmacology*; D005312:Fetal Blood / Q000166:cytology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics*; D015847:Interleukin-4 / Q000494:pharmacology*; D007438:Introns; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid
D016693:Receptors, Antigen, T-Cell, alpha-beta; D015847:Interleukin-4; D007371:Interferon-gamma; D015232:Dinoprostone; D001374:Azacitidine