Perlecan is a large and complex protein composed of multiple modules whichhave growth-regulatory and cell adhesion among its properties. Thesestudies are designed to characterize the heparan sulfate proteoglycanHSPG perlecan in the synovium at the molecular, biochemical andimmunochemical levels and determine the gene expression and regulation ofperlecan in normal synovial cells and synovial cells derived fromrheumatoid arthritis RA and osteoarthritis OA The tissue-specificnature of synovial cell produced perlecan along with any differences inthe gene expression and biochemical characteristics ie size and sidechain composition of perlecan in synovium will be of fundamentalimportance to understanding the function of the synovium. A uniquefeature of this research proposal is that the synovium has been a tissueoverlooked in regard to this proteoglycan primarily due to the normal andexpected distribution of perlecan as part of the basement membrane. Without our recent cloning of the first human perlecan cDNA andsubsequent entire 145 kb cDNA, studies of perlecan mRNA using specifichuman perlecan probes were not possible. In preliminary studies, we haveidentified that synovial cells express perlecan and that there issignificantly less perlecan mRNA expressed in RA synovial cells incomparison to non-arthritic and OA derived synovial cells. Although thecomplex character of the perlecan core protein has been partly elucidatedwhere specific domains could be involved in important biological functionssuch as binding growth factors and prolonging their half-life, the preciserole perlecan occupies in the synovium is presently unknown. Proinflammatory cytokines, IL-1 and TNF-alpha as well as TGF-beta and FGFwill be examined in this proposal for their effects on perlecan genetranscription and biosynthesis. The existence of alternatively splicedperlecan transcripts in synovial cells will be investigated and theeffects of these cytokines on their expression determined. Since perlecanis one of the major components of the classic basement membrane and hadnot been identified in the synovium until these studies, its furthercharacterization in the synovium will provide new and importantinformation. Recent studies show there are shared structural featuresbetween synovium and basement membranes, therefore, it would seem likelythat many of the functions would also be in common. The presence andcharacter of perlecan in the synovium would be of basis importance to re- defining the structure and function of this specialized tissue. Therealized goals of this proposal will substantially add to ourunderstanding of the synovium in normal joint homeostasis and inarthritis-related pathology.

Arthritis; Basement Membrane; Bone Diseases; Fibroblast Growth Factor; Gene Expression; Genetic Transcription; Heparan Sulfate; Human Tissue; Interleukin; Muscle Disorders; Musculoskeletal System; Osteoarthritis; Protein Structure Function; Proteoglycan; Rheumatoid Arthritis; Skeletal Disease; Skin Diseases; Synovial Membrane; Transforming Growth Factor; Tumor Necrosis Factor Alpha