Increased level of translatable collagenase mRNA in rabbit synovial fibroblasts treated with phorbol myristate acetate or crystals of monosodium urate monohydrate

Abstract

A model system for the rheumatoid synovium was developed in which monolayer cultures of rabbit synovial fibroblasts can be stimulated experimentally to produce large amounts of collagenase by treatment with phorbol myristate acetate or crystals of monosodium urate monohydrate. mRNA from these and untreated cells were translated in a wheat germ cell-free system. Collagenase was not present in the culture medium or in the in vitro translation products of mRNA from untreated cells but was present in both the medium and translation products of stimulated cells, as analyzed by gel electrophoresis and immunoprecipitation with monospecific antibody. Induction of collagenase was prevented by treatment of the cells with .alpha.-amanitin (2 .mu.g/ml), an inhibitor of mRNA synthesis. Induction of collagenase synthesis by phorbol myristate acetate or urate crystals is due to an increased level of translatable RNA.