To explore the pattern of cadherin-11 expression and its relationship with synovial inflammation in rheumatoid arthritis (RA), and study the regulatory effects of cytokines on cadherin-11 expression on RA fibroblast-like synoviocytes (RAFLS).
Synovium samples were obtained from 28 RA patients who were undergoing total knee replacement. After HE staining, synovitis score was determined according to Rooney's inflammation score system. The expression of cadherin-11 in RA synovium was semi-quantified by immunohistochemical staining, and its correlations with Rooney's inflammation score and systematic inflammatory markers were analyzed statistically. After induction with transforming growth factor β (TGF-β) or interleukin 17 (IL-17) at a series of concentrations, the expression of cadherin-11 on RAFLS was assessed by real time guantitative-PCR and Western blotting.
There was no significant difference in cadherin-11 expression in RA synovium among different levels of C-reactive protein. Cadherin-11 in the lining and sublining layers were positively correlated with D-dimer, synovial lining layer hyperplasia, proliferating blood vessels, perivascular infiltration of lymphocytes, focal aggregation of lymphocytes and diffuse infiltration of lymphocytes; cadherin-11 in the lining layer was negatively correlated with interstitial fibrosis. TGF-β or IL-17 stimulation could up-regulate cadherin-11 expression on RAFLS at mRNA and protein levels.
The over-expression of cadherin-11 in RA was correlated with synovial lining layer hyperplasia, proliferating blood vessels and infiltration of lymphocytes. Cadherin-11 expression on RAFLS could be induced by TGF-β and IL-17 induction.