title: IL-27 induces Th1 differentiation via p38 MAPK/T-bet- and intercellular adhesion molecule-1/LFA-1/ERK1/2-dependent pathways.
abstract: IL-27, a novel member of the IL-6/IL-12 family, activates both STAT1 and STAT3 through its receptor, which consists of WSX-1 and gp130 subunits, resulting in positive and negative regulations of immune responses. We recently demonstrated that IL-27 induces Th1 differentiation through ICAM-1/LFA-1 interaction in a STAT1-dependent, but T-bet-independent mechanism. In this study, we further investigated the molecular mechanisms by focusing on p38 MAPK and ERK1/2. IL-27-induced Th1 differentiation was partially inhibited by lack of T-bet expression or by blocking ICAM-1/LFA-1 interaction with anti-ICAM-1 and/or anti-LFA-1, and further inhibited by both. Similarly, the p38 MAPK inhibitor, SB203580, or the inhibitor of ERK1/2 phosphorylation, PD98059, partially suppressed IL-27-induced Th1 differentiation and the combined treatment completely suppressed it. p38 MAPK was then revealed to be located upstream of T-bet, and SB203580, but not PD98059, inhibited T-bet-dependent Th1 differentiation. In contrast, ERK1/2 was shown to be located downstream of ICAM-1/LFA-1, and PD98059, but not SB203580, inhibited ICAM-1/LFA-1-dependent Th1 differentiation. Furthermore, it was demonstrated that STAT1 is important for IL-27-induced activation of ERK1/2, but not p38 MAPK, and that IL-27 directly induces mRNA expression of growth arrest and DNA damage-inducible 45gamma, which is known to mediate activation of p38 MAPK. Finally, IL-12Rbeta2 expression was shown to be up-regulated by IL-27 in both T-bet- and ICAM-1/LFA-1-dependent mechanisms. Taken together, these results suggest that IL-27 induces Th1 differentiation via two distinct pathways, p38 MAPK/T-bet- and ICAM-1/LFA-1/ERK1/2-dependent pathways. This is in contrast to IL-12, which induces it via only p38 MAPK/T-bet-dependent pathway.
authors.affiliation: Intractable Immune System Disease Research Center, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Owaki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Asakawa
authors.forename: Fumio
authors.initials: F
authors.lastname: Fukai
authors.forename: Junichiro
authors.initials: J
authors.lastname: Mizuguchi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yoshimoto
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000276:immunology*; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000276:immunology / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology / Q000378:metabolism; D007378:Interleukins / Q000276:immunology* / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050794:STAT1 Transcription Factor / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology*; D020825:T-Box Domain Proteins / Q000276:immunology / Q000378:metabolism; D018417:Th1 Cells / Q000166:cytology* / Q000276:immunology; D048051:p38 Mitogen-Activated Protein Kinases / Q000276:immunology* / Q000378:metabolism; D000098815:T-bet Transcription Factor
chemical_list: D004791:Enzyme Inhibitors; C486767:Il27 protein, mouse; D007378:Interleukins; D016169:Lymphocyte Function-Associated Antigen-1; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; D018799:Intercellular Adhesion Molecule-1; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases