Current evidence suggests that interleukin-1 (IL-1) stimulates production of gingival fibroblast neutral proteinases (e.g., collagenase, proteoglycanase and plasminogen activator) and thereby, has been linked to gingival soft tissue destruction associated with periodontitis. The intracellular biochemical events that link IL-1 gingival fibroblast receptor activation t neutral proteinase production are poorly understood. Recent studies from this laboratory with synovial cells and gingival fibroblasts in culture have provided new information regarding the molecular events associated with the IL-1 induction of cellular proteinases. These studies serve as the basis for the long term objective of the present proposal of defining the intracellular biochemical mechanisms associated with IL-1 activation of gingival fibroblasts. This application proposes experiments designed to shed light on the molecular mechanism(s) by which IL-1 stimulation of gingival fibroblasts are coupled to the biochemical events leading to neural proteinase production.
The specific aims of the proposal are to determine the role of cAMP production, inositol phosphate production, diacylglycerol production, arachidonic acid production, calcium mobilization and protein kinase C activation in IL-1 induced neutral proteinase production. We will use: 1) human recombinant IL-1, 2) primary gingival fibroblast cultures derived from periodontal tissue obtained from patients undergoing periodontal surgery, 3) recombinant DNA neutral proteinase probes and 4) other well established biochemical procedures (e.g., arachidonic acid/diacylglycerol/inositol phosphate measurements, fluorescence spectroscopy measurements of Ca2+ mobilization, radioimmune determinations of cAMP, measurement of protein kinase C and neutral proteinase activity) that are currently performed routinely in this laboratory. These experiments should provide detailed biochemical information on the signal transduction system associated with IL-1 activation of neutral proteinase genes in gingival fibroblasts and thus help further elucidate the molecular basis of gingival soft tissue destruction associated with periodontitis. Consequently, an important therapeutic implication of the present proposal is that blockers of these IL-1 induced biochemical events could be useful clinically as a future treatment of periodontitis.
