Korean J Asthma Allergy Clin Immunol.  2008 Dec;28(4):292-297.

Effects of Co-treatment with Dexamethasone and Troglitazone on Transcription and Secretion of IL-8 in the A549 Airway Epithelial Cells

Abstract

BACKGROUND: Glucocorticoid is a widely used anti-inflammatory agent in a variety of diseases. Recently, peroxisome proliferator activated receptor gamma (PPAR gamma) ligand has been shown to exert a potential anti-inflammatory activity, mainly through their ability to down- regulate pro-inflammatory gene expressions.
Objective
This study was designed to evaluate the effects of co-treatment with dexamethasone and troglitazone (a ligand of PPAR gamma) on IL-8 transcription and secretion. METHOD: Steroid and troglitazone-induced transactivation was measured by using pGRE luciferase reporter gene in the A549 cell line. Steroid-induced transrepression was measured by using stable A549 IgG-NF kappa B luciferase cell line, which contained the minimal IL-8 promoter region. RESULT: Co-treatment with dexamethasone and troglitazone showed no additional increase of transactivation activity compared to dexamethasone single treatment. Suppressions of the transcriptional activity in the IL-8 promotor and IL-8 secretion showed no difference in the co-treatment with dexamethasone and troglitazone compared to those in dexamethasone single treatment.
CONCLUSION
Our results suggest that co-treatment with PPAR gamma ligand and steroid may not have an additive anti- inflammatory activity at least in the airway epithelial cell.

MeSH Terms

Cell Line
Chromans
Dexamethasone
Epithelial Cells
Genes, Reporter
Interleukin-8
Luciferases
Peroxisome Proliferator-Activated Receptors
PPAR gamma
Promoter Regions, Genetic
Thiazolidinediones
Transcriptional Activation
Chromans
Dexamethasone
Interleukin-8
Luciferases
PPAR gamma
Peroxisome Proliferator-Activated Receptors
Thiazolidinediones