ABSTRACT
Objective To investigate the mRNA level of glucocorticoid receptor α (GRα) and heat shock protein 90 (HSP90) in peripheral blood mononuclear cells (PBMCs) and the plasma protein level of macrophage migration inhibitory factor (MIF) in patients with systemic lupus erythematosus (SLE) and to analyze their association with glucocorticoid (GC) resistance.Methods One hundred and six patients with SLE and thirty-eight healthy controls were enrolled in this study.Transcription levels of GRα and HSP90 were determined by real-time polymerase chain reaction.Enzyme-linked immunosorbent assay was used to detect the protein level of plasma MIF.The association between these parameters and GC resistance was analyzed by Spearman correlation analysis.The multivariate logistic regression model was used to analyze the risk factors for GC resistance.Results The mRNA level of GRα and HSP90 in GC resistance group was significantly lower than that in GC sensitive group [10.18(3.12,17.20) vs 16.83(12.01,24.18), P =0.001;18.46(14.77,26.45) vs 25.84 (17.97,35.90), P =0.005].MIF protein level in GC resistance group was significantly higher than that in GC sensitive group [(23.21 ±7.98) μg/L vs (18.34 ±6.29)μg/L;P =0.013].The mRNA level of HSP90 in the high MIF group was significantly lower than that in the low MIF group [23.67 (13.84,28.32) vs 26.64 (23.61,47.16);P =0.001], as well as HSP90/GRαratio(P =0.008).Additionally, the plasma protein level of MIF was negatively correlated with HSP90 (r =-0.275, P =0.004) and HSP90/GRα ratio(r =-0.341, P ＜ 0.001).SLE activity index score in GC resistance group was significantly higher than that in GC sensitive group [(12.23 ±2.86) μg./L vs (9.63 ± 3.48) μg/L;P =0.003].Logistic regression model indicated that disease activity was an independent risk factor for GC resistance (OR =17.481, 95％ CI 1.747-174.903, P =0.015).Conclusions Our preliminary findings suggest that low mRNA level of GRα and HSP90 and high protein level of MIF are associated with GC resistance.Elevated MIF level in SLE patients may play an important role in the development of GC resistance through down-regulating HSP90 and destabilizing the balance of HSP90/ Grα.Disease activity is the risk factor for GC resistance, which might be the viable evidence of therapy response.
ABSTRACT
Objective To analyze the differences with the expression of glucocorticoids receptor isoforms ( GRα, GRβ, GRγand GR-P ) and cytokines [ IL-6, macrophage migration inhibitory factor (MIF), IFN-γand IL-10] between patients with systemic lupus erythematosus (SLE) and rheumatoid ar-thritis ( RA) , and to further understand their correlations with disease activities.Methods Fifty-five pa-tients with SLE, forty-nine patients with RA and thirty-eight healthy subjects were recruited in this study. All patients were steroid-naive.The expression of GRα, GRβ, GRγ, and GR-P in peripheral blood mononu-clear cells at transcript levels were determined by real-time PCR.Enzyme-linked immunosorbent assay was used to detect the expression of IL-6, MIF, IFN-γand IL-10 in serum samples.Results The percentages of GRαin all subjects were the highest among four isoforms of GR, followed by GR-P, GRγand GRβ.Com-pared with healthy subjects, patients with SLE or RA showed significantly decreased expression of GRα( P<0.05), but increased expression of GR-P (P<0.05).The percentages of GR-P in patients with RA were higher than those in patients with SLE (P<0.05).The expression of GRαwas negatively correlated with SLE disease activity index (SLEDAI) and disease activity score 28 (DAS28).SLE or RA patients with high disease activity showed lower expression of GRαthan those with low disease activity.The levels of IL-6, IFN-γand MIF in patients with SLE or RA were significantly higher than those in healthy subjects ( P<0.05).A negative correlation was observed between the expression of IL-6 and GRαin patients with SLE (P<0.05).The expression of IFN-γwas negatively correlated with GRαin patients with RA (P<0.05). Conclusion There were significant differences with the expression of GR isoforms among patients with SLE, patients with RA and healthy subjects, indicating the change of internal environment in patients might be in-volved in GR alternative splicing.GRαwas the predominant isoform and was negatively correlated with dis-ease activities.Oversecretion of cytokines resulted in a decreased expression of GRα.This study would be useful for the diagnosis of the disease status and for monitoring clinical treatment.