The contact of human macrophages with extracellular matrix proteins selectively induces expression of proinflammatory cytokines

The interaction of macrophages with proteins of the extracellular matrix (E CM) is important for the regulation of the immune and nonimmune functions d isplayed by these cells, Little, however, is known about the ability of dif ferent ECM proteins to transmit inflammatory signals into macrophages. Here we investigated the effect of the ECM proteins collagen type I, fibrin and fibronectin on the expression of the proinflammatory cytokines interleukin -1 beta (IL-1 beta) and IL-8 using RT-PCR, Northern and Western blot analys is and ELISA technique. It was found that collagen strongly induced IL-1 be ta and IL-8 expression in the macrophages. Fibronectin also stimulated cyto kine expression, however, the amounts of the specific mRNAs were significan tly lower compared to those induced by collagen. On the protein level IL-1 beta revealed a close correlation to the mRNA expression. In contrast, fibr in did not elicit any IL-1 beta and IL-8 response. These data show that dif ferent ECM proteins vary in their ability to induce proinflammatory cytokin e expression in human macrophages suggesting that the protein composition o f the ECM might be crucial in the initiation of inflammatory processes. Cop yright (C) 2000 S. Karger AG. Basel.