J. Fraley (Sacramento, US)
UC Davis Health Orthopaedic SurgeryPresenter Of 1 Presentation
P054 - Cartilage Oligomeric Matrix Protein C-terminus Peptides Bind TGFb-superfamily Growth Factors
Abstract
Purpose
BMP-2 and TGF-β1 belong to the TGFβ-superfamily of growth factors and are important for bone and cartilage development, respectively. Both growth factors are not freely diffusive, but bound to extracellular matrix (ECM) components that present these growth factor to cell surface receptors. Cartilage oligomeric matrix protein (COMP) is a major non-collagenous ECM protein found in bone and cartilage. We previously reported that COMP directly binds BMP-2 and TGF-β1 and enhanced their activity in osteogenesis and chondrogenesis, respectively. Here, we identified critical amino acid residues, residing in two separate regions within the C-terminus of COMP that are important for BMP-2 and TGF-β1 interactions.
Methods and Materials
28 nested peptides (15 aa in length) within the C-terminal domain of COMP were synthesized and tested for their abilities to interfere with the binding of full-length COMP to immobilized BMP-2 or TGF-β1 in a competitive ELISA assay. We identified two peptides, representing sequences YAGFIFGYQDSSSFY (aa 596-611), and CFSQENIIWANLRYR (aa 726-741) that interfere with COMP binding to BMP-2 and TGF-β1 (Fig 1A). Adjacent overlapping peptides did not interfere, which narrowed critical residues to the inner five of each peptide.
Results
These two interfering peptides mapped to two distinct sites within the COMP C-terminal domain (Fig. 1B). Next, we tested different alanine scanning point mutants of each peptide in a competitive ELISA to identify individual residue(s) involved in BMP-2/TGF-b1 binding. Results showed that three residues (aa FGQ, FGQ, and GQD) within the first peptide were indispensable for BMP-2 binding, while four residues within the second peptide are partially responsible for binding interference (Fig 1C, D).
Conclusion
Further testing is required to confirm direct binding of these two interfering peptides to BMP-2/TGF-β1, and their effects on osteogenic and chondrogenic activities. These two interfering peptides have the potential to be developed as hybrid molecular carriers for BMP-2 and TGF-β1 in tissue engineering.
Presenter Of 1 Presentation
P054 - Cartilage Oligomeric Matrix Protein C-terminus Peptides Bind TGFb-superfamily Growth Factors
Abstract
Purpose
BMP-2 and TGF-β1 belong to the TGFβ-superfamily of growth factors and are important for bone and cartilage development, respectively. Both growth factors are not freely diffusive, but bound to extracellular matrix (ECM) components that present these growth factor to cell surface receptors. Cartilage oligomeric matrix protein (COMP) is a major non-collagenous ECM protein found in bone and cartilage. We previously reported that COMP directly binds BMP-2 and TGF-β1 and enhanced their activity in osteogenesis and chondrogenesis, respectively. Here, we identified critical amino acid residues, residing in two separate regions within the C-terminus of COMP that are important for BMP-2 and TGF-β1 interactions.
Methods and Materials
28 nested peptides (15 aa in length) within the C-terminal domain of COMP were synthesized and tested for their abilities to interfere with the binding of full-length COMP to immobilized BMP-2 or TGF-β1 in a competitive ELISA assay. We identified two peptides, representing sequences YAGFIFGYQDSSSFY (aa 596-611), and CFSQENIIWANLRYR (aa 726-741) that interfere with COMP binding to BMP-2 and TGF-β1 (Fig 1A). Adjacent overlapping peptides did not interfere, which narrowed critical residues to the inner five of each peptide.
Results
These two interfering peptides mapped to two distinct sites within the COMP C-terminal domain (Fig. 1B). Next, we tested different alanine scanning point mutants of each peptide in a competitive ELISA to identify individual residue(s) involved in BMP-2/TGF-b1 binding. Results showed that three residues (aa FGQ, FGQ, and GQD) within the first peptide were indispensable for BMP-2 binding, while four residues within the second peptide are partially responsible for binding interference (Fig 1C, D).
Conclusion
Further testing is required to confirm direct binding of these two interfering peptides to BMP-2/TGF-β1, and their effects on osteogenic and chondrogenic activities. These two interfering peptides have the potential to be developed as hybrid molecular carriers for BMP-2 and TGF-β1 in tissue engineering.