Toll-like receptor–mediated cytokine production is differentially regulated by glycogen synthase kinase 3

Abstract

The cellular mechanisms that directly regulate the inflammatory response after Toll-like receptor (TLR) stimulation are unresolved at present. Here we report that glycogen synthase kinase 3 (GSK3) differentially regulates TLR-mediated production of pro-and anti-inflammatory cytokines. Stimulation of monocytes or peripheral blood mononuclear cells with TLR2, TLR4, TLR5 or TLR9 agonists induced substantial increases in interleukin 10 production while suppressing the release of proinflammatory cytokines after GSK3 inhibition. GSK3 regulated the inflammatory response by differentially affecting the nuclear amounts of transcription factors NF-κB subunit p65 and CREB interacting with the coactivator CBP. Administration of a GSK3 inhibitor potently suppressed the proinflammatory response in mice receiving lipopolysaccharide and mediated protection from endotoxin shock. These findings demonstrate a regulatory function for GSK3 in modulating the inflammatory response.The ability of the innate immune system to recognize and respond to microbial components has been largely attributed to the family of type I transmembrane receptors called Toll-like receptors (TLRs) 1,2 . TLRs are expressed mainly on antigen-presenting cells such as monocytes-macrophages and dendritic cells and show an ability to discriminate among distinct molecular patterns associated with microbial components. Recognition of microbial products by TLRs leads to a variety of signal transduction pathways that regulate the nature, magnitude and duration of the inflammatory response 3 . Although the production of proinflammatory cytokines is important for mediating the initial host defense against invading pathogens 4 , an inability to regulate the nature or duration of the host's inflammatory response can be detrimental, as in chronic inflammatory diseases. The underlying cellular mechanisms that directly control pro-versus anti-inflammatory cytokine production after TLR stimulation are unresolved, but studies have shown the TLR signaling pathway can activate phosphatidylinositol 3-OH kinase (PI(3)K) 5 to limit production of tumor necrosis factor (TNF) and interleukin 12 (IL-12) 6-8 . Moreover, TLR2-induced activation of the PI(3)K pathway enhances IL-10 production, whereas IL-12 production is reduced 9 . Those studies suggested critical involvement of the PI(3)K pathway in differentially controlling pro-and antiinflammatory cytokine production, but it is unclear at present if this pathway is limited to TLR2 signaling and how production of other inflammatory mediators induced by other TLR ligands is affected. Here we have characterized how intracellular TLR signaling affected 'downstream' effector molecules of the PI(3)K pathway to determine if a central effector molecule is responsible for mediating the ability of this pathway to differentially dictate the host's inflammatory response. Inhibition of glycogen synthase kinase 3 (GSK3), the constitutively active downstream kinase of the PI(3)K pathway, mediated the ability of this pathway to selectively...

Novel anti-inflammatory agent 3-[(dodecylthiocarbonyl)-methyl]-glutarimide ameliorates murine models of inflammatory bowel disease

“…An earlier study by Takeiri phosphorylation-mediated GSK-3β inactivation resulted in anti-inflammatory reactions [34,35], we believe that GSK-3β suppression in macrophages is a likely mechanism of DTCM-G-mediated inhibition of inflammatory colon injury. Indeed, inhibiting GSK-3β via phosphoinositide 3-kinase knockdown prevented self-induced colitis [36].…”

The Role of Glycogen Synthase Kinase 3-β in Immunity and Cell Cycle: Implications in Esophageal Cancer

“…However, as pointed out with IL-12, it is still unclear if elevated IL-1 levels are contributing to EC disease severity or are merely a sign of disease progression since it has been demonstrated that IL-1 has potent anti-tumor effects. Our studies (Martin et al 2005;Rehani et al 2009) identified the ability of GSK3b activation to enhance production of IL1b and suppress its antagonist IL-1Ra level indicating that GSK3 activation suppresses tumor progression through its ability to enhance IL-1 production (Fig. 2).…”

“…Our lab and others have demonstrated that GSK3b activity enhances the production of TNF in different cell types (Agarwal et al 2013;Martin et al 2005), which potentially makes GSK3-mediated regulation of TNF a factor in EC development (Fig. 2).…”

“…Collectively, these studies have demonstrated the protumorigenesis effect of IL-6 and inhibition of GSK3b has been established as a strong IL-6 suppressor in different cell types (Grzesiak et al 2005;Martin et al 2005). GSK3 inhibition might be an important therapeutic approach, at least in terms of IL-6, to suppress the progression of EC by diminishing the levels of IL-6 either in tumor tissue or serum.…”

“…1). Phosphorylation of GSK3 can be mediated by Akt (Martin et al 2005), P70S6K (Peyrollier et al 2000), P90RSK (Saito et al Fig. 1 Regulation of GSK3 and its substrates specificity.…”