Mineralized tissues contain in their extracellular matrix a protein factor which has the capacity to induce chondrogenesis and osteogenesis in soft tissues that normally do not form cartilage or bone. Urist has called this factor BMP, the bone morphogenetic protein. Efforts to characterize this protein from bone have not been successful because of the small amount and highly interactive nature of BMP, and the complex composition of the bone. Moreover, the assay systems, involving in vivo implantation, have required large amounts of protein. We have approached this problem from two fresh perspectives: 1) an in vitro cell culture assay has been developed; 2) use has been made of the fact that dentin matrix has a higher BMP activity than bone matrix. In our initial studies we have demonstrated the presence of a factor in the rat dentin matrix which is chondrogenic in vitro and osteogenic in vivo, extracted and fractionated the noncollagenous proteins, located the fraction with fractionated the noncollagenous proteins, located the fraction with fractionated the noncollagenous proteins, located the fraction with fractionated the noncollagenous proteins, located the fraction with in vitro chondrogenic activity, and shown that nonmyogenic nionatal rat muscle fibroblasts have receptors for its uptake. We now propose to: 1) purify the CIA to homogeneity and obtain its amino aid sequence; 2) determine its in vivo activity; 3) prepare immunologic and nucleotide probes for its identification; 4) quantitate the receptor binding site and determine the nature of the receptor and the uptake process; 5) examine the role of growth factors and other regulatory agents on its activity in vitro; and 6) explore the use of CIA in vivo in bone defect repair. We believe that these studies can be of immense importance in bringing closer the application of chondrogenic and osteogenic agents to the repair of bone defects.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE008525-05
Application #
3222295
Study Section
Special Emphasis Panel (SRC)
Project Start
1987-09-01
Project End
1992-08-31
Budget Start
1991-09-01
Budget End
1992-08-31
Support Year
5
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Type
Schools of Dentistry
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
Tompkins, Kevin; Alvares, Keith; George, Anne et al. (2005) Two related low molecular mass polypeptide isoforms of amelogenin have distinct activities in mouse tooth germ differentiation in vitro. J Bone Miner Res 20:341-9
Veis, A (2003) Amelogenin gene splice products: potential signaling molecules. Cell Mol Life Sci 60:38-55
Veis, A; Tompkins, K; Alvares, K et al. (2000) Specific amelogenin gene splice products have signaling effects on cells in culture and in implants in vivo. J Biol Chem 275:41263-72
Nebgen, D R; Inoue, H; Sabsay, B et al. (1999) Identification of the chondrogenic-inducing activity from bovine dentin (bCIA) as a low-molecular-mass amelogenin polypeptide. J Dent Res 78:1484-94
Weiner, S; Veis, A; Beniash, E et al. (1999) Peritubular dentin formation: crystal organization and the macromolecular constituents in human teeth. J Struct Biol 126:27-41
Inoue, H; Nebgen, D; Veis, A (1995) Changes in phenotypic gene expression in rat mandibular condylar cartilage cells during long-term culture. J Bone Miner Res 10:1691-7
Amar, S; Sires, B; Sabsay, B et al. (1991) The isolation and partial characterization of a rat incisor dentin matrix polypeptide with in vitro chondrogenic activity. J Biol Chem 266:8609-18
Veis, A; Sires, B; Clohisy, J et al. (1990) Rat incisor dentine contains a factor which alters the phenotypic expression and stimulates chondrogenesis in fibroblast-like cells in vitro. Biomaterials 11:35-7
Veis, A; Sires, B; Clohisy, J (1989) A search for the osteogenic factor in dentin. Rat incisor dentin contains a factor stimulating rat muscle cells in vitro to incorporate sulfate into an altered proteoglycan. Connect Tissue Res 23:137-44