title: Glycogen synthase kinase-3β indirectly facilitates interferon-γ-induced nuclear factor-κB activation and nitric oxide biosynthesis.
abstract: Either glycogen synthase kinase (GSK)-3β or nuclear factor (NF)-κB regulates interferon (IFN)-γ-induced nitric oxide (NO) biosynthesis; however, the inter-regulation between GSK-3β and NF-κB is unknown. We have previously shown that IFN-γ-activated GSK-3β negatively regulates Src homology-2 domain-containing phosphatase (SHP) 2 to facilitate Janus kinase (Jak) 2-signal transducer and activator of transcription (STAT) 1 activation. Because Jaks-IFN-inducible dsRNA-activated serine-threonine protein kinase (PKR) axis signaling is essential for IFN-γ-activation of NF-κB, in this study we investigate the potential mechanism for GSK-3β-facilitated NF-κB activation in IFN-γ-stimulated RAW264.7 murine macrophages. Pharmacological inhibitors of GSK-3β or NF-κB signaling, such as the inhibitor of κB (IκB) kinase β (IKKβ) and IκBα, inhibited IFN-γ-induced inducible NO synthase (iNOS) and thus NO biosynthesis. Inhibiting GSK-3β decreased IFN-γ-induced NF-κB phosphorylation (Ser536) and activation. The upstream regulators for GSK-3β activation, including okadaic acid-sensitive protein phosphatase and proline-rich tyrosine kinase 2, were also important for IFN-γ-induced IκBα phosphorylation (Ser32) and degradation. Under IFN-γ stimulation, Jak2-PKR axis signaling induced IκBα inactivation as well as iNOS/NO biosynthesis. It is notable that inhibiting GSK-3β caused SHP2-mediated dephosphorylation of PKR (Thr446), IKKβ (Ser180), and NF-κB (Ser536). Taken together, we provide the first evidence to demonstrate that GSK-3β indirectly facilitates IFN-γ-induced NF-κB activation by inhibiting SHP2, in turn activating the PKR-IKKβ-IκBα axis signaling pathway.
authors.affiliation: Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Jui-In
authors.initials: JI
authors.lastname: Kai
authors.forename: Wei-Ching
authors.initials: WC
authors.lastname: Huang
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Tsai
authors.forename: Wen-Teng
authors.initials: WT
authors.lastname: Chang
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Chen
authors.forename: Chiou-Feng
authors.initials: CF
authors.lastname: Lin
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D024202:Electrophoretic Mobility Shift Assay; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D007211:Indoles / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D010091:Oximes / Q000494:pharmacology; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects; D013844:Thiazoles / Q000494:pharmacology; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: C483321:6-bromoindirubin-3'-oxime; D007211:Indoles; D016328:NF-kappa B; D010091:Oximes; D013844:Thiazoles; D009569:Nitric Oxide; D007371:Interferon-gamma; C479831:N-(4-methoxybenzyl)-N'-(5-nitro-1,3-thiazol-2-yl)urea; D014508:Urea; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3