Production of tissue inhibitor of metalloproteinases 3 is selectively enhanced by calcium pentosan polysulfate in human rheumatoid synovial fibroblasts

Objective To determine the effects of calcium pentosan polysulfate (CaPPS) on the production of matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMP), in cultures of rheumatoid synovial fibroblasts. Methods. The production of MMP-1, -2, -3, -7, -8, -9, and -13 and of TIMP-1 , -2, -3, and -4 in cultured rheumatoid synovial fibroblasts treated with 0 .1, 1, and 10 mu g/ml CaPPS in the presence and absence of 100 units/ml int erleukin-1 alpha (IL-1 alpha) was examined by a sandwich enzyme immunoassay system and/or immunoblotting. The messenger RNA (mRNA) expression of TIMP- 3 and membrane type 1 MMP was determined by Northern blotting, and the cell s expressing TIMP-3 gene in rheumatoid synovium were identified by in situ hybridization, The synthesis and secretion of TIMP-3 protein were monitored by pulse-chase experiments. TIMP-3 was immunolocalized in untreated or CaP PS-treated rheumatoid synovial fibroblasts and synovium using an avidin-bio tin-peroxidase complex method. Results. Treatment of cultured rheumatoid synovial fibroblasts with CaPPS r esulted in a dose-dependent increase in the production of TIMP-3 in both ce ll lysates and media from the treated cells. However, CaPPS did not affect the levels of the other MMPs or TIMPs examined. The production of TIMP-3 wa s further enhanced in the cells treated with both IL-1 alpha and CaPPS. Imm unohistochemistry confirmed the enhanced production of TIMP-3 by cells expo sed to CaPPS, The mRNA level of TIMP-3 increased 3.4-fold by treating rheum atoid synovial fibroblasts with IL-1 alpha, but CaPPS itself did not alter the expression levels in the IL-1 alpha-treated or -untreated cells. Pulse- chase studies demonstrated that translation for TIMP-3 protein was enhanced by CaPPS treatment, In situ hybridization and immunohistochemistry indicat ed that TIMP-3 was expressed mainly in the hyperplastic lining cells of rhe umatoid synovium, and that the production of this protein by these immunore active lining cells was significantly increased by treatment with CaPPS. Conclusion. The present study is the first to demonstrate that the new anti arthritic drug, CaPPS, selectively enhanced TIMP-3 production at the posttr anscription level in cultured rheumatoid synovial fibroblasts and in the li ning cells of rheumatoid synovium. By this mechanism, CaPPS may be able to modulate joint tissue destruction in rheumatoid arthritis.