title: Convergence of the mammalian target of rapamycin complex 1- and glycogen synthase kinase 3-β-signaling pathways regulates the innate inflammatory response.
abstract: The PI3K pathway and its regulation of mammalian target of rapamycin complex 1 (mTORC1) and glycogen synthase kinase 3 (GSK3) play pivotal roles in controlling inflammation. In this article, we show that mTORC1 and GSK3-β converge and that the capacity of mTORC1 to affect the inflammatory response is due to the inactivation of GSK3-β. Inhibition of mTORC1 attenuated GSK3 phosphorylation and increased its kinase activity. Immunoprecipitation and in vitro kinase assays demonstrated that GSK3-β associated with a downstream target of mTORC1, p85S6K, and phosphorylated GSK3-β. Inhibition of S6K1 abrogated the phosphorylation of GSK3-β while increasing and decreasing the levels of IL-12 and IL-10, respectively, in LPS-stimulated monocytes. In contrast, the direct inhibition of GSK3 attenuated the capacity of S6K1 inhibition to influence the levels of IL-10 and IL-12 produced by LPS-stimulated cells. At the transcriptional level, mTORC1 inhibition reduced the DNA binding of CREB and this effect was reversed by GSK3 inhibition. As a result, mTORC1 inhibition increased the levels of NF-κB p65 associated with CREB-binding protein. Inhibition of NF-κB p65 attenuated rapamycin's ability to influence the levels of pro- or anti-inflammatory cytokine production in monocytes stimulated with LPS. These studies identify the molecular mechanism by which mTORC1 affects GSK3 and show that mTORC1 inhibition regulates pro- and anti-inflammatory cytokine production via its capacity to inactivate GSK3.
authors.affiliation: Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY 40202, USA. hhwang01@louisville.edu
authors.forename: Huizhi
authors.initials: H
authors.lastname: Wang
authors.forename: Jonathan
authors.initials: J
authors.lastname: Brown
authors.forename: Zhen
authors.initials: Z
authors.lastname: Gu
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Garcia
authors.forename: Ruqiang
authors.initials: R
authors.lastname: Liang
authors.forename: Pascale
authors.initials: P
authors.lastname: Alard
authors.forename: Eléonore
authors.initials: E
authors.lastname: Beurel
authors.forename: Richard S
authors.initials: RS
authors.lastname: Jope
authors.forename: Terrance
authors.initials: T
authors.lastname: Greenway
authors.forename: Michael
authors.initials: M
authors.lastname: Martin
mesh_terms: D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D002469:Cell Separation; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D015870:Gene Expression; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000276:immunology; D038362:Glycogen Synthase Kinase 3 / Q000276:immunology* / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D047468:Immunoprecipitation; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D000076222:Mechanistic Target of Rapamycin Complex 1; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D046912:Multiprotein Complexes; D011506:Proteins / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology*; D058570:TOR Serine-Threonine Kinases
chemical_list: D016207:Cytokines; D046912:Multiprotein Complexes; D011506:Proteins; D000071679:Glycogen Synthase Kinase 3 beta; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; D038362:Glycogen Synthase Kinase 3