title: Nitric oxide reduces bacterial superantigen-immune cell activation and consequent epithelial abnormalities.
abstract: Inhibition of the inducible form of nitric oxide (NO) synthase prolonged the murine enteropathy evoked by the bacterial superantigen, Staphylococcus aureus enterotoxin B (SEB). We examined the ability of NO to alleviate SEB-induced epithelial dysfunction and immune cell activation. Human peripheral blood mononuclear cells (PBMC) were activated by SEB for 24 h +/- the NO donors, S-nitroso-N-acetylpenicillamine and spermine-NONOate. The conditioned medium (CM) was collected and applied to T84 epithelial monolayers, and permeability [i.e., transepithelial resistance (TER)] and stimulated ion transport (i.e., short-circuit current responses to carbachol and forskolin) were assessed 24 h later. Exposure to CM led to an approximately 40% drop in TER and hyporesponsiveness to both secretagogues. CM made in the presence of NO donors (10(-4) M) had no significant effect on epithelial barrier or ion transport parameters. NO donors alone had no effect on naive epithelia, and addition of the NO donors to previously made CM did not affect the ability of this CM to alter epithelial function. Moreover, the NO donors dose-dependently reduced SEB-evoked PBMC proliferation and cytokine production (i.e., interferon-gamma, tumor necrosis factor alpha) but did not affect viability. These findings suggest a beneficial role for NO in inflammation by reducing immune cell activation and thus ameliorating consequent physiological abnormalities, in this instance, perturbed epithelial permeability and active ion transport.
authors.affiliation: Intestinal Disease Research Programme, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Alisa
authors.initials: A
authors.lastname: Rachlis
authors.forename: James L
authors.initials: JL
authors.lastname: Watson
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Derek M
authors.initials: DM
authors.lastname: McKay
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology*; D002217:Carbachol / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects / Q000502:physiology; D005576:Colforsin / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004768:Enterotoxins / Q000276:immunology*; D004847:Epithelial Cells / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics; D007413:Intestinal Mucosa / Q000166:cytology; D017136:Ion Transport / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects*; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009589:Nitrogen Oxides; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D013096:Spermine / Q000031:analogs & derivatives* / Q000494:pharmacology; D018089:Superantigens / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D017077:Culture Media, Conditioned; D004768:Enterotoxins; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; C110881:S-nitro-N-acetylpenicillamine; D018089:Superantigens; D014409:Tumor Necrosis Factor-alpha; C091861:spermine nitric oxide complex; D005576:Colforsin; D013096:Spermine; D009569:Nitric Oxide; C031818:enterotoxin B, staphylococcal; D026423:S-Nitroso-N-Acetylpenicillamine; D007371:Interferon-gamma; D002217:Carbachol; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D010396:Penicillamine