15-Deoxy-delta(12,14)-prostaglandin J2 (15d-PGJ2) is an agonist for peroxisome proliferator-activated receptor-gamma (PPAR-gamma), which plays an important role in various biological processes including inflammatory responses. We have addressed the effect of 15d-PGJ2 on the expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) in a cell line derived from human bronchial epithelial cells (BEAS-2B). Besides being a hematopoietic growth factor, GM-CSF activates mature leukocytes and is involved in regulation of inflammatory responses. Cultures of BEAS-2B were stimulated with interleukin-1beta (IL-1beta), and the expressions of GM-CSF mRNA and protein were analyzed by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. IL-1beta stimulated the expression of GM-CSF in BEAS-2B cells in concentration- and time-dependent manners. When the cells were pretreated with 15d-PGJ2 for 1 hour, the IL-1beta-induced GM-CSF expression was inhibited in a concentration-dependent manner (2-50 microM). Ciglitazone, another agonist of PPAR-gamma, did not affect the IL-1beta-induced GM-CSF expression in BEAS-2B cells. A PPAR-gamma antagonist, bisphenol A diglycide ether (BADGE), did not reverse the inhibitory effects of 15d-PGJ2 on GM-CSF expression. 15d-PGJ2 regulates GM-CSF expression in the bronchial epithelium, which may be mediated through a mechanism unrelated to PPAR-gamma.