Hypersecretion of mucin in response to inflammatory mediators by guinea pig tracheal epithelial cells in vitro is blocked by inhibition of nitric oxide synthase.
Primary cultures of guinea pig tracheal epithelial cells in air/liquid interface were exposed to one of four agents associated with airway inflammation: the peptide histamine (100 microM), the lipid mediator platelet-activating factor (1 microM), the cytokine tumor necrosis factor-alpha (15 ng/ml; specific activity 2.86 x 10(7) U/mg), or enzymatically generated reactive oxygen species (purine [500 microM]+xanthine oxidase [20 mU/ml]). Effects of each of these substances on release of mucin by guinea pig tracheal epithelial (GPTE) cells were measured using a monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA). Each secretagogue significantly enhanced release of mucin, but the stimulatory effect of each was inhibited by pre-(+)co-incubation of the cells with the competitive inhibitor of nitric oxide synthase, NG-monomethyl-L-arginine (L-NMA), but not by NG-monomethyl-D-arginine (D-NMA), the inactive stereoisomer that does not inhibit nitric oxide synthase. Neither L-NMA nor D-NMA affected mucin secretion by themselves. The results suggest that each of these inflammation-associated mediators provokes airway epithelial mucin secretion via a mechanism involving intracellular production of nitric oxide (NO) as a critical signaling molecule.
Adler
K B
KB
Department of Anatomy, Physiological Sciences and Radiology, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.
Fischer
B M
BM
Li
H
H
Choe
N H
NH
Wright
D T
DT
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D018836:Inflammation Mediators / Q000494:pharmacology*; D009077:Mucins / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D010972:Platelet Activating Factor / Q000187:drug effects; D012636:Secretory Rate / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism; D014132:Trachea / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019323:omega-N-Methylarginine
D004791:Enzyme Inhibitors; D018836:Inflammation Mediators; D009077:Mucins; D010972:Platelet Activating Factor; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D019323:omega-N-Methylarginine; D006632:Histamine; D001120:Arginine; D019001:Nitric Oxide Synthase