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Critical Role of Glycogen Synthase Kinase-β in Regulating the Avian Heterophil Response to Salmonella enterica Serovar Enteritidis
- Michael H. Kogut, Christina L. Swaggerty, Hsin-I Chiang, Kenneth J. Genovese, Haiqi He, Huaijun Zhou, Ryan J. Arsenault
- Frontiers in Veterinary Science 2014 v.1 no.10 pp. -
- Salmonella Enteritidis, anti-inflammatory activity, antibodies, bacteria, bacterial infections, chickens, enzyme activity, enzyme-linked immunosorbent assay, gene expression, gene expression regulation, glycogen (starch) synthase, heterophils, immune response, interleukin-10, interleukin-6, lithium chloride, phosphorylation, signal transduction, tau-protein kinase, transcription factor NF-kappa B
- A microarray-assisted gene expression screen of chicken heterophils revealed glycogen synthase kinase-3β (GSK-3β), a multifunctional Ser/Thr kinase, to be consistently upregulated 30–180 min following stimulation with Salmonella enterica serovar Enteritidis (S. Enteritidis). The present study was designed to delineate the role of GSK-3β in regulating the innate function of chicken heterophils in response to S. Enteritidis exposure. Using a specific GSK-3β ELISA assay, 30 min after infection with S. Enteritidis, heterophils had a significant decrease (p ≤ 0.05) in total GSK-3β, but a significant increase (p ≤ 0.05) in phosphorylated GSK-3β (Ser9). By 60 min post-infection, there was no difference in the amount of phosphorylated GSK-3β (Ser9) in either the uninfected and infected heterophils. S. Enteritidis interaction with heterophils alters GSK-3β activity by stimulating phosphorylation at Ser9 and that peaks by 30 min post-infection. Further, inhibition of GSK3β with lithium chloride resulted in a significant decrease (p ≤ 0.05) in NF-kβ activation and expression of IL-6, but induces a significant increase (p ≤ 0.05) in the expression of the anti-inflammatory cytokine, IL-10. Using a phospho-specific antibody array confirmed the phosphorylation of GSK-3β (Ser9) as well as the phosphorylation of the downstream cytokine-activated intracellular signaling pathway involved in stimulating immune responses, IkB, the IkB subunit IKK-β, and the NF-kB subunits p105, p65, and c-Rel. Our data revealed that the phosphorylation of GSK-3β (Ser9) is responsible for inducing and controlling an innate response to the bacteria. Our findings suggest that the repression of GSK-3 activity is beneficial to the host cell and may act as a target for treatment in controlling intestinal colonization in chickens. Further experiments will define the in vivo modulation of GSK-3 as a potential alternative to antibiotics in salmonella and other intestinal bacterial infections.