Dual specificity protein phosphatase 3 and tumor necrosis factor-α as prognostic biomarkers and their regulation by tripterygium glycosides in rheumatoid arthritis

Abstract

Objective To investigate the prognostic value of dual specificity protein phosphatase 3(DUSP3) and tumor necrosis factor-α(TNF-α) and how tripterygium glycosides(TG) regulate DUSP3 and TNF-α expression in patients with rheumatoid arthritis(RA). Methods A total of 67 patients with RA receiving treatment with TG tablets in our hospital between March, 2016 and January, 2018 and 67 healthy volunteers were enrolled in this study. The expression of DUSP3 and TNF-α in the peripheral blood mononuclear cells(PBMCs) of the participants was detected using real-time PCR(RT-PCR), and the results were analyzed using the receiver operating curve(ROC). In U937 cells stimulated with lipopolysaccharide(LPS), the effects of TG on the expressions of DUSP3, TNF-α and their upstream and downstream pathways were investigated using RT-PCR, Western blotting and chromatin immunoprecipitation(ChIP). Results Compared with the healthy volunteers, the RA patients showed significantly reduced DUSP3 expression and increased TNF-α expression in the PBMCs(P < 0.05), whose areas under the curve(AUC) were 0.948 and 0.908, respectively. Treatment with TG tablets resulted in significantly decreased 28-joint Disease Activity score(DAS28), erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP), increased expression of DUSP3 and decreased TNF-α expression in the RA patients(P < 0.05). Significant differences were found in the expression of DUSP3 and TNF-α between the RA patients who responded to the treatment and the non-responding patients(with bone erosion, P < 0.05). ROC analysis showed that the AUC of DUSP3 and TNF-α was 0.821 and 0.747, respectively, for predicting the patients' response to TG treatment(defined by the changes in DAS28). In LPS-stimulated U937 cells, the changes in DUSP3 or TNF-α expression did not affect the expression of one another. The rescue experiments demonstrated that nuclear factor-κB(NF-κB) mediated the inhibitory effect of TG on TNF-α expression. ChIP experiments confirmed that TG suppressed the conjugation of HDAC1 with DUSP3 promoter; Western blotting showed that TG inhibited LPS-induced up-regulation of HDAC1 and down-regulation of DUSP3. Conclusion TG tablet produces good therapeutic effect on RA by reducing the expression of TNF-α and relieving the inhibition on DUSP3. DUSP3 and TNF-α can serve as prognostic biomarkers for RA patients receiving treatment with TG tablets.

Keywords

• tripterygium glycosides
• rheumatoid arthritis
• prognostic factors
• dual specificity protein phosphatase 3
• tumor necrosis factor-α