We propose to study the role and distribution of osteonectin, the major noncollagenous protein in bone, by analyzing: (1) osteonectin's location during bone mineralization in organ culture (20 day fetal rat calvaria) by immunofluorescence; (2) osteonectin's and bone -carboxyglutamic acid-containing proteins (BGP) role in mineralization in organ culture with antibody neutralization techniques; (3) osteonectin's relationship with other extracellular matrix proteins (ECM) (type 1 collagen, BGP and fibronectin) in organ culture; (4) osteonectin's effect on osteoblast adhesion, morphology and phenotype expression in cell culture (rat osteosarcoma-derived osteoblastic cell line ROS 17/2.8). Additionally we plan to study by radioimmunoassay the modulation of osteoblastic osteonectin production; (5) during bone mineralization in organ culture, and (6) by hormones which influence bone turnover; parathyroid hormone, 1,25(OH) 2D3 and glucocorticoids, and (7) on collagen, fibronectin and osteonectin coated substrates in cell culture. A mineralizing organ culture of fetal rat calvaria which we have developed will be further characterized by quantitating collagen production and by studying collagen organization by polarized light microscopy.
Our aim i s to determine the distribution and role of ECM components, in particular osteonectin, in relation to osteoblast growth and differentiation in organ culture where the original bone architecture is maintained. Knowledge of the relationship of specific ECM components with each other, their effect on osteoblast phenotype and their modulation by hormones will lead to a better understanding of the function of ECM proteins in bone. Our eventual goal is to learn how to manipulate ECM components to promote normal bone growth and remodeling in vivo for the successful osseointegration of implants, in diseases such as osteoporosis, and traumatic injuries to bone.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29AR038636-05
Application #
3456812
Study Section
General Medicine B Study Section (GMB)
Project Start
1988-04-01
Project End
1994-03-31
Budget Start
1992-04-01
Budget End
1994-03-31
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Connecticut
Department
Type
Schools of Medicine
DUNS #
City
Farmington
State
CT
Country
United States
Zip Code
06030
Gohel, A R; Hand, A R; Gronowicz, G A (1995) Immunogold localization of beta 1-integrin in bone: effect of glucocorticoids and insulin-like growth factor I on integrins and osteocyte formation. J Histochem Cytochem 43:1085-96
Gronowicz, G A; McCarthy, M B (1995) Glucocorticoids inhibit the attachment of osteoblasts to bone extracellular matrix proteins and decrease beta 1-integrin levels. Endocrinology 136:598-608
Doherty, W J; DeRome, M E; McCarthy, M B et al. (1995) The effect of glucocorticoids on osteoblast function. The effect of corticosterone on osteoblast expression of beta 1 integrins. J Bone Joint Surg Am 77:396-404
Rosenthal, A K; Ryan, L M (1994) Probenecid inhibits transforming growth factor-beta 1 induced pyrophosphate elaboration by chondrocytes. J Rheumatol 21:896-900
Gronowicz, G A; Derome, M E (1994) Synthetic peptide containing Arg-Gly-Asp inhibits bone formation and resorption in a mineralizing organ culture system of fetal rat parietal bones. J Bone Miner Res 9:193-201
Gronowicz, G; Hadjimichael, J; Richards, D et al. (1992) Correlation between tumor necrosis factor-alpha (TNF-alpha)-induced cytoskeletal changes and human collagenase gene induction. J Periodontal Res 27:562-8
Gronowicz, G A; DeRome, M E; McCarthy, M B (1991) Glucocorticoids inhibit fibronectin synthesis and messenger ribonucleic acid levels in cultured fetal rat parietal bones. Endocrinology 128:1107-14
Gronowicz, G; Woodiel, F N; McCarthy, M B et al. (1989) In vitro mineralization of fetal rat parietal bones in defined serum-free medium: effect of beta-glycerol phosphate. J Bone Miner Res 4:313-24