Open AccessThe oxido‐reductase enzyme glutathione peroxidase 4 ( GPX4 ) governs S almonella T yphimurium‐induced neutrophil transepithelial migration
Author(s) -
Agbor Terence A.,
Demma Zachary,
Mrsny Randall J.,
Castillo Antonio,
Boll Erik J.,
McCormick Beth A.
Publication year - 2014
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/cmi.12290
Subject(s) - gpx4 , biology , proinflammatory cytokine , secretion , phospholipid hydroperoxide glutathione peroxidase , microbiology and biotechnology , glutathione peroxidase , glutathione , inflammation , biochemistry , enzyme , immunology
Summary Neutrophil (polymorphonuclear leucocytes; PMN ) transmigration across mucosal surfaces contributes to dysfunction of epithelial barrier properties, a characteristic underlying many mucosal inflammatory diseases. Using S almonella enterica serovar T yphimurium ( S . T yphimurium) as a prototypic proinflammatory insult, we have previously reported that the eicosanoid hepoxilin A 3 ( HXA 3 ), an endogenous product of 12‐lipoxygenase (12‐ LOX ) activity, is secreted from the apical surface of the intestinal epithelium to establish a chemotactic gradient that guides PMN across the epithelial surface. Since little is known regarding the molecular mechanisms that regulate 12‐ LOX during S . T yphimurium infection, we investigated this pathway. We found that expression of phospholipid glutathione peroxidase ( GPX4 ), which is known to have an inhibitory effect on 12‐ LOX activity, is significantly decreased at both the mRNA and protein level during infection with S . Typhimurium. Moreover, employing intestinal epithelial cell monolayers expressing siRNA against GPX4 mRNA , S . T yphimurium‐induced PMN migration was significantly increased compared with the non‐specific siRNA control cells. Conversely, in cells engineered to overexpress GPX4 , S . T yphimurium‐induced PMN migration was significantly decreased, which is consistent with the finding that partial depletion of GPX4 by RNAi resulted in a significant increase in HXA 3 secretion during S . T yphimurium infection. Mechanistically, although we found S almonella entry not to be required for the induced decrease in GPX4 , the secreted effector, SipA , which is known to induce epithelial responses leading to stimulation of HXA 3 , governed the decrease in GPX4 in a process that does not lead to an overall increase in the levels of ROS . Taken together, these results suggest that S . T yphimurium induces apical secretion of HXA 3 by decreasing the expression of phospholipid GPX , which in turn leads to an increase in 12‐ LOX activity, and hence HXA 3 synthesis.