title: Calcium/calmodulin-dependent protein kinase II regulates IL-10 production by human T lymphocytes: a distinct target in the calcium dependent pathway.
abstract: Calcium (Ca2+) plays an essential role in lymphocyte activation and differentiation by affecting signaling pathways leading to cytokine production. Among the enzymes responding to calcium increase, Ca2+/calmodulin-dependent protein kinase II (CaMKII) has been involved in anergy with a still poorly characterized role. IL-10 produced by different T lymphocyte subpopulations is critical mediator of tolerance. We tested the hypothesis that CaMKII may be involved in IL-10 production. We report that CaMKII upregulates IL-10 production by primary human T lymphocytes stimulated through the antigen receptor or bypassing that. Overexpression of constitutively active mutant forms of Calcineurin or CaMKII specifically increase IL-10 protein product and IL-10 mRNA accumulation in T lymphocytes. By cotransfecting constitutively active CaMKII with luciferase reporter plasmids carrying specific fragments or the whole IL-10 promoter, we show that CaMKII specifically activates IL-10 promoter activity, whereas it inhibits IL-2 and IL-4 promoter. This effect is mediated by the first 500 bp fragment, which contains binding sites for Myocyte Enhancer Factor-2 (MEF2). A constitutively active mutant of CaMKII activated a luciferase reporter plasmid under the control of MEF2, when cotransfected in T lymphocytes stimulated by Ionomycin and PMA, whereas its inhibitor KN-62 inhibited MEF2 binding in cell lysates of the same cells. Moreover, overexpression of MEF2 enhanced by 2.5-fold IL-10 promoter activity. Our data for the first time suggest a distinct role of CaMKII in the induction of anergy in T lymphocytes, by differential regulation of IL-10 and IL-2 gene transcription suggest MEF2 as a molecular target which can integrate different calcium signals.
authors.affiliation: Department of Microbiology, School of Medicine, University of Patras, Asclepiou Street, 26500 Patras, Greece.
authors.forename: Stavroula
authors.initials: S
authors.lastname: Boubali
authors.forename: Kassiani
authors.initials: K
authors.lastname: Liopeta
authors.forename: Laura
authors.initials: L
authors.lastname: Virgilio
authors.forename: George
authors.initials: G
authors.lastname: Thyphronitis
authors.forename: George
authors.initials: G
authors.lastname: Mavrothalassitis
authors.forename: George
authors.initials: G
authors.lastname: Dimitracopoulos
authors.forename: Fotini
authors.initials: F
authors.lastname: Paliogianni
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D001483:Base Sequence; D019703:Calcineurin / Q000378:metabolism; D065095:Calcineurin Inhibitors; D020013:Calcium Signaling; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000235:genetics; D026161:MADS Domain Proteins / Q000235:genetics; D064326:MEF2 Transcription Factors; D018006:Myogenic Regulatory Factors / Q000235:genetics; D011401:Promoter Regions, Genetic; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D065095:Calcineurin Inhibitors; C508609:IL10 protein, human; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; C578043:MEF2D protein, human; D018006:Myogenic Regulatory Factors; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D016753:Interleukin-10; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D019703:Calcineurin