DIFFERENTIATION DEPENDENCY OF EICOSANOID ENZYME EXPRESSION IN HUMAN TRACHEOBRONCHIAL CELLS

The expression of 15-lipoxygenase (15-LO) and prostaglandin H synthase -2 (PGHS-2) was studied in retinoic acid (RA) sufficient and RA-defici ent normal human tracheobronchial epithelial (NHTBE) cell cultures. In the absence of RA, in which the cultures became squamous metaplastic, neither 15-LO nor PGHS-2 were expressed. In RA-sufficient cultures, w hich differentiated into a mucociliary epithelium, both enzymes were e xpressed: PGHS-2 during early phases and 15-LO during late stages of d ifferentiation. Depending on the stage of differentiation, the RA-suff icient cultures produced PGE, and in the presence of exogenous linolei c acid (LA) 13-HODE. Experiments are underway to examine the effects o f inflammatory cytokines on eicosanoid metabolism and the role these m etabolites play in airway diseases. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.