Critical Role of Glycogen Synthase Kinase-3β 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

doi:10.3389/fvets.2014.00010

Critical Role of Glycogen Synthase Kinase-3β in Regulating the Avian Heterophil Response to Salmonella enterica Serovar Enteritidis

Front Vet Sci. 2014 Nov 24:1:10. doi: 10.3389/fvets.2014.00010. eCollection 2014.

Authors

Michael H Kogut¹, Christina L Swaggerty¹, Hsin-I Chiang², Kenneth J Genovese¹, Haiqi He¹, Huaijun Zhou³, Ryan J Arsenault¹

Affiliations

¹ Southern Plains Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture , College Station, TX , USA.
² Department of Animal Sciences, National Chung Hsing University , Taichung , Taiwan.
³ Department of Animal Science, University of California Davis , Davis, CA , USA.

Abstract

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-κB 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, IκB, the IκB subunit IKK-β, and the NF-κB 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.

Keywords: Salmonella; chickens; glycogen synthase kinase-3ß; heterophils; innate immunity.