title: A conventional protein kinase C inhibitor targeting IRF-3-dependent genes differentially regulates IL-12 family members.
abstract: Protein kinase C (PKC) isoforms play a critical role in the regulation of innate immune responses. We have previously demonstrated that conventional PKC (cPKC) α is involved in interferon regulatory factor 3 (IRF-3) activation and IFN-β synthesis. Herein, we investigated the role of cPKCs in the regulation of IL-12 family members expression mediated by the Toll-like receptor 3 (TLR3) and TLR4. First, inhibition of cPKCs activity in human DCs by a cPKC-specific inhibitor, Gö6976 downregulated the expression of IL-12p70 and IL-27p28 but not IL-12/IL-23p40, IL-23, IL-27EBI3 induced by LPS or poly(I:C). Furthermore, reporter gene assays in RAW 264.7 macrophages showed that cPKCs regulate IL-12p35 and IL-27p28 promoter activities since Gö6976 repressed LPS and poly(I:C)-mediated transcriptional activities of IL-12p35 and IL-27p28. In contrast, no effect was observed with IL-12/IL-23p40 and IL-23p19 reporter constructs. These results prompted us to study the role of IRF-3 on IL-23 expression. Bone marrow-derived DC (BMDCs) from IRF-3(-/-) mice produced comparable levels of IL-23 induced by both LPS and poly(I:C) as compared to wild type BMDCs, indicating that IRF-3 is not involved in IL-23 production. Finally, BMDCs from PKCα(-/-) mice displayed a reduced synthesis of IL-27 induced by poly(I:C). Collectively, these data identify cPKCs as critical components that control IRF-3-dependent IL-12p35 and IL-27p28 gene expression downstream of TLR3 and TLR4.
authors.affiliation: Institute for Medical Immunology, Université Libre de Bruxelles (ULB), Charleroi, Belgium.
authors.forename: Jolyn
authors.initials: J
authors.lastname: Johnson
authors.forename: Céline
authors.initials: C
authors.lastname: Molle
authors.forename: Ezra
authors.initials: E
authors.lastname: Aksoy
authors.forename: Michel
authors.initials: M
authors.lastname: Goldman
authors.forename: Stanislas
authors.initials: S
authors.lastname: Goriely
authors.forename: Fabienne
authors.initials: F
authors.lastname: Willems
mesh_terms: D000818:Animals; D002227:Carbazoles / Q000494:pharmacology; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D005786:Gene Expression Regulation; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism*; D018664:Interleukin-12 / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D020381:Interleukin-17 / Q000096:biosynthesis / Q000235:genetics; D053759:Interleukin-23 / Q000096:biosynthesis / Q000235:genetics; D007378:Interleukins / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology; D051379:Mice; D008822:Mice, Transgenic; D011070:Poly I-C / Q000276:immunology; D016133:Polymerase Chain Reaction; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D051196:Toll-Like Receptor 3 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D002227:Carbazoles; C486767:Il27 protein, mouse; D050838:Interferon Regulatory Factor-3; D020381:Interleukin-17; D053759:Interleukin-23; D007378:Interleukins; D008070:Lipopolysaccharides; D051196:Toll-Like Receptor 3; D051197:Toll-Like Receptor 4; C081021:Go 6976; D018664:Interleukin-12; D011493:Protein Kinase C; D011070:Poly I-C