title: Ovocalyxin-36 is an effector protein modulating the production of proinflammatory mediators.
abstract: Sepsis is a systemic inflammatory response syndrome during infection. Therapeutic agents are essential to protect the host from sepsis. Ovocalyxin-36 (OCX-36) is a chicken eggshell membrane protein and shares protein sequence and gene organization homology with bactericidal permeability-increasing protein (BPI), lipopolysaccharide-binding protein (LBP) and palate, lung and nasal epithelium clone (PLUNC) proteins that play a major role in innate immune protection. We recently reported that OCX-36 binds to both lipopolysaccharide (LPS) and lipoteichoic acid (LTA) (Cordeiro et al., 2013, PLoS ONE 8, e84112), which is an important activity to neutralize endotoxins and non-endotoxin pyrogens during an inflammatory response. Here we investigated the immune modulating effects of OCX-36 and enzymatically digested OCX-36 (dOCX-36) in vitro and in a mouse model of endotoxemia. OCX-36 alone dose-dependently induced both TNF-α and nitric oxide (NO) production by RAW 264.7 macrophage cells, and this immunostimulatory effect was reduced by enzymatic digestion. In the presence of LPS, dOCX-36 was more effective than intact OCX-36 at reducing LPS-induced secretion of TNF-α from RAW 264.7 cells, but did not reduce NO production. In contrast, OCX-36 increased LPS-induced NO production, both in the presence and absence of FBS, PCR array analysis confirmed that OCX-36 and dOCX-36 differentially regulated genes involved in innate immunity, and dOCX-36 down-regulated the expression of genes involved in LPS signaling and inflammatory responses. In vivo, dOCX-36 was more effective at reducing LPS-induced inflammatory symptoms and inhibiting the local production of pro-inflammatory mediators in the small intestine. These results suggest that OCX-36 and OCX-36 derived peptides may differentially modulate innate immune responses, and support our hypothesis that OCX-36 derived peptides have potential therapeutic applications in sepsis.
authors.affiliation: Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Kovacs-Nolan
authors.affiliation: Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5.
authors.forename: Cristianne
authors.initials: C
authors.lastname: Cordeiro
authors.affiliation: Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
authors.forename: Denise
authors.initials: D
authors.lastname: Young
authors.affiliation: Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Mine
authors.affiliation: Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5. Electronic address: mhincke@uottawa.ca.
authors.forename: Maxwell
authors.initials: M
authors.lastname: Hincke
mesh_terms: D000818:Animals; D002460:Cell Line; D004527:Egg Proteins / Q000494:pharmacology*; D007249:Inflammation / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D016133:Polymerase Chain Reaction; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D004527:Egg Proteins; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide
keywords: Gene expression; Innate immunity; Lipopolysaccharide; Ovocalyxin-36