Adiponectin greatly stimulated the expression of matrix metalloproteinases (MMPs) in fibroblast-like synoviocytes (FLSs) as did IL-1beta. We wondered whether taurine chloramine (TauCl) inhibits the production of MMPs stimulated by adiponectin in the same pattern as by IL-1beta stimulation in vitro
Synovial cells from rheumatoid arthritis (RA) patients were treated with adiponectin or interleukin (IL)-1beta for 24 hr in the presence or absence of TauCl. The culture supernatant was collected and the levels of MMPs were measured by enzyme-linked immunosorbent assay (ELISA). The IkappaB signaling pathways stimulated by adiponectin were studied and the levels of NF-kappaB in the nuclei of the cells were analyzed by ELISA.
TauCl (600 microM) inhibited MMP-13, but not MMP-1, expression in IL-1beta-stimulated RA FLSs. However, TauCl at the same concentration significantly inhibited the production of both adiponectin-stimulated MMP-1 and MMP-13 expression. TauCl inhibited the degradation of IkappaB-alpha stimulated by adiponectin, but not by IL-1beta. Similarly, the level of NF-kappaB in the nucleus was increased by adiponectin stimulation and was inhibited by 600 microM TauCl. However, the levels of NF-kappaB increased by IL-1beta stimulation were not inhibited by 600 microM TauCl.
TauCl more effectively inhibited MMPs expression induced by adiponectin than that by IL-1beta in RA FLS, suggesting that TauCl plays an important role in down-regulating the expression of MMPs in arthritic joints.