To evaluate the modulation of RhoA/Rho kinase (ROCK) signaling pathway, a small Rho GTPase that is considered as an important modulator in inflammatory responses, on Toll-like receptor-2 mediated chemokine secretion in fibroblast-like synoviocytes (FLS) from rheumatoid arthritis (RA) patients.
The RhoA activity was measured by a pull-down assay. And the ROCK activity was assessed by Western blot. The secretion of chemokines was measured by ELISA (enzyme-linked immunosorbent assay). MTT test was used to detect the cellular viability.
The stimulation of peptidoglycan (PG, 5 mg/L) increased the levels of IL-8 (interleukin-8), RANTES (regulated upon activation normal T cell expressed & secreted) and MCP-2 (monocyte chemotactic protein-2) and boosted the activities of RhoA and ROCK versus the unstimulated RA FLS. And these effects of PG were suppressed by anti-TLR-2 monoclonal antibody. Inhibition of RhoA and ROCK with a specific inhibitor inhibited the secretion of IL-8, RANTES and MCP-2 in PG-induced RA FLS.
The present study provides novel evidence that the RhoA/ROCK signal pathway modulates the TLR-2-mediated secretion of chemokines in RA FLS. It suggests that the inhibition of RhoA/ROCK may be a new therapeutic approach for RA.