The long term objective of the project is to understand the bone matrix collagen assembly, specifically the role of type V collagen in bone matrix. There is a growing body of evidence indicating that collagen- collagen interactions may play an important role in controlling fiber diameter and also in providing fibril network with reinforcement, thereby specifying the mechanical properties of different tissues. Although a lot of information has been gathered on type V collagen, its function in bone or other tissues remains poorly understood. Three approaches will be explored for understanding the role of type V collagen in bone matrix. The first will be to determine the potential of type V collagen to copolymerize with type 1 collagen by analysis of the nature of intermolecular cross-linking in bone type V collagen. Secondly, to determine the role of the retained extension peptides on the tissue form of type V collagen, and thirdly to assess the mode of type V collagen degradation. All the intermolecular cross-linking sites in bone type V collagen involving sodium borohydride reducible cross-links and also those involving the mature 3-hydroxypyridinolines will be determined. The reducible cross-links in type V collagen will be determined after reacting the collagen with tritiated sodium borohydride to label the cross-linking bonds. Cross-linked peptides involving 3-hydroxypyridinium residues in type V collagen will be followed by their fluorescence, purified and subjected to protein microsequencing analysis. The role of the extension peptides retained on the tissue form of type V collagen will be assessed by generating the extension peptides from the alpha chains by bacterial collagenase digestion and then producing monospecific antibodies against the extension peptides. The generated antibodies will then be used to examine the role of these extension peptides in bone collagen fibrils. The mode of type V collagen degradation by type V collagenase will be determined by incubating native type V collagen with type V collagenase. The initial sites of attack within the type V collagen will be determined by aminoterminal sequence analysis of the generated fragments. Understanding the bone matrix collagen assembly may help to explain how increased ratio of type V to type I collagen in osteogenesis imperfecta patients may impair structural integrity of the bone tissue and contribute to mechanical weakness.

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 #
5R29AR042720-05
Application #
2736512
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1994-03-01
Project End
2000-02-29
Budget Start
1998-03-01
Budget End
2000-02-29
Support Year
5
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Orthopedics
Type
Schools of Medicine
DUNS #
053785812
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Balk, M L; Bray, J; Day, C et al. (1997) Effect of rhBMP-2 on the osteogenic potential of bone marrow stromal cells from an osteogenesis imperfecta mouse (oim). Bone 21:7-15
Sagarriga Visconti, C; Kavalkovich, K; Wu, J et al. (1996) Biochemical analysis of collagens at the ligament-bone interface reveals presence of cartilage-specific collagens. Arch Biochem Biophys 328:135-42
Niyibizi, C; Sagarrigo Visconti, C; Gibson, G et al. (1996) Identification and immunolocalization of type X collagen at the ligament-bone interface. Biochem Biophys Res Commun 222:584-9
Niyibizi, C; Visconti, C S; Kavalkovich, K et al. (1995) Collagens in an adult bovine medial collateral ligament: immunofluorescence localization by confocal microscopy reveals that type XIV collagen predominates at the ligament-bone junction. Matrix Biol 14:743-51
Niyibizi, C; Chan, R; Wu, J J et al. (1994) A 92 kDa gelatinase (MMP-9) cleavage site in native type V collagen. Biochem Biophys Res Commun 202:328-33