Korean J Asthma Allergy Clin Immunol.  2005 Jun;25(2):123-129.

Effect of GRbeta Over-expression on Steroid-induced Suppression of IL-8 Synthesis and Secretion

Abstract

BACKGROUND
There are few reports about the effect of GRbeta on glucocorticoid-induced suppression of inflammatory cytokines, and GRbeta as a dominant negative inhibitor of GRalpha signaling is still uncertain.
OBJECTIVE
We investigated the functional role of GRbeta expression in glucocorticoid-induced suppression of IL-8 synthesis and secretion. METHOD: Expression of mRNA and secretion of IL-8 were measured by RT-PCR and ELISA, respectively, in the A549 lung epithelial cell lines. Suppression of IL-8 production induced by glucocorticoid was compared with or without pCMV GRbeta over-expression. RESULT: Expression of mRNA and secretion of IL-8 were not affected with overexpression of GRbeta. GRbeta had some suppressive effects on IL-8 production, but was not significant. CONCLUSION: This study suggests that GRbeta do not act as a dominant negative inhibitor of GRalpha in the steroid-induced suppression of IL-8 in the airway epithelial cell, and that GRbeta expression may not be the major cause of steroid resistance.

MeSH Terms

Cytokines
Enzyme-Linked Immunosorbent Assay
Epithelial Cells
Interleukin-8*
Lung
RNA, Messenger
Cytokines
Interleukin-8
RNA, Messenger