Paeoniflorin-6′-O-benzene sulfonate down-regulates CXCR4-Gβγ-PI3K/AKT mediated migration in fibroblast-like synoviocytes of rheumatoid arthritis by inhibiting GRK2 translocation

Objective: This study aims to explore the effect of paeoniflorin-6'-O-benzene sulfonate (CP-25) on the migration of fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) and the mechanism focused on CXCR4-G beta gamma-PI3K/AKT signaling. Methods: Human synovial tissues were collected from RA and osteoarthritis (OA) patients. Immunohistochemistry (IHC) and Western blot were used to detect the protein expression of CXCR4, GRK2, G beta gamma, PI3K, p-PI3K, AKT and p-AKT. Transwell was adopted to analyse the migration of fibroblast-like synoviocytes (FLS). Co-immunoprecipitation (Co-IP) and laser scanning confocal microscopy (LSCM) were used to detect the combination of GRK2 and G beta gamma, the combination of PI3K and G beta gamma. Results: The expression level of CXCR4, GRK2, G beta gamma, p-p85 and p-AKT were increased in RA synovial tissue according to the results of IHC and Western blot. In vitro, the migration of FLS was increased after stimulation of CXCL12, inhibition of G beta gamma suppressed the migration and phosphorylation of p85 and AKT induced by CXCL12 in FLS, and CP-25 had the same effect as inhibition of G beta gamma. The membrane expression of GRK2, G beta gamma, PI3K and the combination of GRK2 and Guy, the combination of PI3K and G beta gamma in FLS were increased after the stimulation of CXCL12, and CP-25 had an ability in reducing the membrane expression and the combination of these proteins. Conclusion: Excessive migration of FLS in RA was associated with over-activation of PI3K/AKT signaling, and the activity of G beta gamma was involved in the over-activation of PI3K/AKT. CP-25 down-regulated CXCR4-G beta gamma-PI3K/AKT signals by inhibiting GRK2-G beta gamma complex membrane translocation. (C) 2020 Elsevier Inc. All rights reserved.