IL-1 MODIFIES SYSTEM A TRANSPORT ACTIVITY IN HUMAN RHEUMATOID SYNOVIAL-CELLS

Given the importance of interleukin-1 in both rheumatic diseases and t he modulation of cell metabolic activities, we studied the action of t his cytokine on the neutral amino acid transport A system on rheumatoi d synovial cells. In these cells IL-1 (1ng/ml) induced amino transport stimulation from 5 min to 5 h. This effect was obtained only after a starvation period. No concentration-related effect was found for IL-1- stimulated MeAIB uptake, and the IL-1-mediated MeAIB uptake stimulatio n is independent of protein synthesis. Neosynthesis or post-translatio nal maturation of protein transport is a prerequisite for obtaining th is effect. In conclusion, rheumatoid synovial cells exhibit a higher s ensitivity for IL-1 than osteoarthritic ones, probably related to thei r intense metabolic activity. (C) 1997 Academic Press Limited.