The major thrust of this research proposal is to examine the role of energy metabolism in the initiation of mineralization of the epiphyseal growth cartilage. We will test the hypothesis that a change in energy metabolism results in phosphate and calcium fluxes leading to mineral deposition. Utilizing innovative high resolution image processing techniques we will generate metabolic maps of the growth cartilage and relate cell redox, adenine nucleotide levels and oxygen tension, at the cytochromes, to maturation and calcification of the cartilage. These maps will permit us to explore the influence of the vascular canals of the growth cartilage on chondrocyte metabolism and the development of mineralization. We will also relate energy status of the cells to their mineral content. We will use cell cultures to determine how calcium and phosphate ions and vitamin D control the redox status of chondrocytes. For this purpose, culture systems will be used in which we can monitor matrix vesicle biogenesis and chondrogenesis; these functions will be related to energy metabolism of the cells, vesicle formation and mineralization. Another goal of the proposal is to ascertain whether changes in redox and energy charge lead to changes in membrane lipids; we will measure membrane lipids and the generation of inositol phosphates by the growth cartilage can cells in culture and examine their influence on cell calcium transport. Finally, we will also determine how energy metabolism modulates membrane permeability and potential. This will be achieved using dyes to probe plasma and mitochondrial membranes. Further, we will measure cytosolic calcium concentrations and relate ion flux to membrane potential, cell redox, energy metabolism and mineralization.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR034411-06
Application #
3156845
Study Section
General Medicine B Study Section (GMB)
Project Start
1984-07-01
Project End
1992-12-31
Budget Start
1990-01-01
Budget End
1990-12-31
Support Year
6
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Type
Schools of Dentistry
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Iwamoto, M; Yagami, K; Shapiro, I M et al. (1994) Retinoic acid is a major regulator of chondrocyte maturation and matrix mineralization. Microsc Res Tech 28:483-91
Haselgrove, J C; Shapiro, I M; Silverton, S F (1993) Computer modeling of the oxygen supply and demand of cells of the avian growth cartilage. Am J Physiol 265:C497-506
Iwamoto, M; Shapiro, I M; Yagami, K et al. (1993) Retinoic acid induces rapid mineralization and expression of mineralization-related genes in chondrocytes. Exp Cell Res 207:413-20
Kim, J K; Haselgrove, J C; Shapiro, I M (1993) Measurement of metabolic events in the avian epiphyseal growth cartilage using a bioluminescence technique. J Histochem Cytochem 41:693-702
Chung, C H; Golub, E E; Forbes, E et al. (1992) Mechanism of action of beta-glycerophosphate on bone cell mineralization. Calcif Tissue Int 51:305-11
Funanage, V L; Carango, P; Shapiro, I M et al. (1992) Creatine kinase activity is required for mineral deposition and matrix synthesis in endochondral growth cartilage. Bone Miner 17:228-36
Shapiro, I M; Debolt, K; Funanage, V L et al. (1992) Developmental regulation of creatine kinase activity in cells of the epiphyseal growth cartilage. J Bone Miner Res 7:493-500
Pacifici, M; Golden, E B; Adams, S L et al. (1991) Cell hypertrophy and type X collagen synthesis in cultured articular chondrocytes. Exp Cell Res 192:266-70
Shapiro, I M; Leboy, P S; Tokuoka, T et al. (1991) Ascorbic acid regulates multiple metabolic activities of cartilage cells. Am J Clin Nutr 54:1209S-1213S
Matsumoto, H; Silverton, S F; Debolt, K et al. (1991) Superoxide dismutase and catalase activities in the growth cartilage: relationship between oxidoreductase activity and chondrocyte maturation. J Bone Miner Res 6:569-74

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