title: IFN-beta production by TLR4-stimulated innate immune cells is negatively regulated by GSK3-beta.
abstract: TLR 4 stimulation of innate immune cells induces a MyD88-independent signaling pathway that leads to the production of IFN-beta. In this study, we demonstrate glycogen synthase kinase 3-beta (GSK3-beta) plays a fundamental role in this process. Suppression of GSK3-beta activity by either pharmacological inhibition, small interfering RNA-mediated gene silencing, or ectopic expression of a kinase-dead GSK3-beta mutant enhanced IFN-beta production by TLR4-stimulated macrophages. Conversely, ectopic expression of a constitutively active GSK3-beta mutant severely attenuated IFN-beta production. GSK3-beta was found to negatively control the cellular levels of the transcription factor c-Jun and its nuclear association with ATF-2. Small interfering RNA-mediated knockdown of c-Jun levels abrogated the ability of GSK3-beta inhibition to augment IFN-beta, demonstrating that the ability of GSK3 to control IFN-beta production was due to its ability to regulate c-Jun levels. The ability of GSK3 inhibition to control IFN-beta production was confirmed in vivo as mice treated with a GSK3 inhibitor exhibited enhanced systemic levels of IFN-beta upon LPS challenge. These findings identify a novel regulatory pathway controlling IFN-beta production by TLR4-stimulated innate immune cells.
authors.affiliation: Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY 40202, USA.
authors.forename: Huizhi
authors.initials: H
authors.lastname: Wang
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Garcia
authors.forename: Kunal
authors.initials: K
authors.lastname: Rehani
authors.forename: Caglar
authors.initials: C
authors.lastname: Cekic
authors.forename: Pascale
authors.initials: P
authors.lastname: Alard
authors.forename: Denis F
authors.initials: DF
authors.lastname: Kinane
authors.forename: Thomas
authors.initials: T
authors.lastname: Mitchell
authors.forename: Michael
authors.initials: M
authors.lastname: Martin
mesh_terms: D051698:Activating Transcription Factor 2 / Q000276:immunology / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D038362:Glycogen Synthase Kinase 3 / Q000276:immunology / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D016899:Interferon-beta / Q000096:biosynthesis* / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D053594:Myeloid Differentiation Factor 88 / Q000172:deficiency / Q000235:genetics; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051197:Toll-Like Receptor 4 / Q000276:immunology*
chemical_list: D051698:Activating Transcription Factor 2; C497106:Atf2 protein, mouse; D008070:Lipopolysaccharides; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016755:Proto-Oncogene Proteins c-jun; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D016899:Interferon-beta; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3