Regulation of the inducible cyclo-oxygenase pathway in human cultured airway epithelial (A549) cells by nitric oxide (original) (raw)

1 In airway epithelium, nitric oxide (NO) is synthesized in the setting of in¯ammation by inducible nitric oxide synthase (iNOS). Although the role of epithelial derived NO in the regulation of human airways is unknown, prostaglandin E 2 (PGE 2 ) is recognised as an important inhibitory mediator in human airways. Cyclo-oxygenase (COX) is the rate limiting enzyme in the production of prostanoids and since in¯ammatory pathways enhance the expression of an inducible COX (COX-2), both COX-2 and iNOS may be co-expressed in response to an in¯ammatory stimulus. Although regulation of the COX-2 pathway by NO has been demonstrated in animal models, its potential importance in human airway epithelium has not been investigated.