Glutathione reductase is essential for host defense against bacterial infection (P1239)

Abstract

Abstract Glutathione reductase (Gsr) catalyzes the reduction of glutathione disulfide to glutathione. We have recently shown that Gsr is essential for host defense against Escherichia coli in a mouse model of sepsis. While we have demonstrated that Gsr is required for the oxidative burst and the development of NETs, the role of Gsr in other phagocytic functions remains unclear. It is also unclear whether Gsr-null mice exhibit host defense defects against Gram-positive bacteria. Here we characterized the effects of Gsr deficiency on the innate immune responses to group B Streptococcus and LPS. Like E. coli, group B Streptococcus also resulted in a substantially more robust cytokine response, a markedly higher morbidity and mortality, and greater bacterial burden in Gsr-null mice than in wildtype mice. Interestingly, Gsr-deficient mice did not exhibit a greater sensitivity to LPS than did wildtype mice. Analysis of Gsr-null neutrophils revealed an impaired phagocytosis. In response to thioglycollate stimulation, Gsr-null mice mobilized far fewer phagocytes, including neutrophils, macrophages, and eosinophils, into their peritoneal cavities than did wildtype mice. The defective phagocyte mobilization is associated with heavy oxidation and aggregation of ascitic proteins, particularly albumin. Our results indicate that the oxidative defense mechanism mediated by Gsr is required for an effective innate immune response against bacteria, likely by preventing phagocyte dysfunction due to oxidative damage.