Glucocorticoid receptor and heat shock protein 90 in peripheral blood mononuclear cells from asthmatics

Objective To investigate the expression of glucocorticoid receptor (GR) and heat shock protein 90 (HSP90) mRNA in peripheral blood mononuclear cells ( PBMCs) from steroid-sensitive (SS), steroid-dependent (SD) and steroid-resi stant (SR) asthmatics patients, and to evaluate the role of GR and HSP90 in the pathogenesis of SR. Methods Reverse transcription-polymerase chain reaction ( RT-PCR) was used to determine the expressions of GR and HSP90 mRNA in PBMC stimulated with I L-2 and/or IL-4 from 10 normal volunteers, 10 SS, 5 SD and 6 SR patients. Results The expressions of GR and HSP90 mRNA were the highest in PBMC from SR patients (0.730 +/- 0.171 and 1.122 +/- 0.165, respectively) compared wi th the normals ( P < 0.05). The second was from SS patients (0.359 +/- 0.35 0 and 0.885 +/- 0.250, respectively). The lowest was from the SD patients ( 0.017 +/- 0.008 and 0.078 +/- 0.039, respectively). The ratio of HSP90/GR i n SR was significantly lower than that in the others, and it suggested that the expression of HSP90 mRNA was not sufficient in this group of patients. When PBMC from SS, SD and SR was incubated with IL-2 or IL-4 alone, no cha nges in GR and HSP90 mRNA expression were observed. While incubated with co mbination of IL-2 and IL-4, a significantly higher expression of GR mRNA wa s observed in all asthmatics, and a significantly higher expression of HSP9 0 mRNA was observed only in SS and SD patients. Conclusion The lowering of HSP90/GR ratio may be one of the causes of SR. I L-2 and IL-4 may play roles in the imbalance of HSP90/GR.