Effects of transforming growth factor beta on the production of prostaglandin E and caseinase activity of unstimulated and interleukin 1-stimulated human articular chondrocytes in culture

Transforming growth factor beta (TGF beta) has previously been shown tohave actions on chondrocytes and cartilage both in vitro and in vivo whichsuggest a role in connective tissue repair. In particular, some of itsactions have been shown to be antagonistic to those of interleukin 1(IL-1). In this study, the effects of TGF beta on prostaglandin E (PGE)production and caseinase activity, in the presence and absence of IL-1, inhuman articular chondrocytes were investigated. TGF beta 1 and TGF beta 2were shown to modulate IL-1 beta-stimulated PGE production and caseinaseactivity. Both TGF beta 1 and beta 2 inhibited IL-1 beta-stimulated PGEproduction in the absence of serum and augmented it in the presence ofserum. TGF beta 1 and TGF beta 2 inhibited IL-1-stimulated caseinaseactivity with and without serum. In general, the TGF beta s had little orno effect on basal PGE or caseinase levels. TGF beta s may be importantmodulators of chondrocyte metabolism, their effects on PGE production maydepend on cytokine interactions; furthermore, their effects on caseinaseactivity may help prevent cartilage breakdown.