Chimeric Peptides of Statherin and Osteopontin That Bind Hydroxyapatite and Mediate Cell Adhesion

Abstract

Extracellular matrix proteins play key roles in controlling the activities of osteoblasts and osteoclasts in bone remodeling. These bone-specific extracellular matrix proteins contain amino acid sequences that mediate cell adhesion, and many of the bone-specific matrix proteins also contain acidic domains that interact with the mineral surface and may orient the signaling domains. Here we report a fusion peptide design that is based on this natural approach for the display of signaling peptide sequences at biomineral surfaces. Salivary statherin contains a 15-amino acid hydroxyapatite binding domain (N15) that is loosely helical in solution. To test whether N15 can serve to orient active peptide sequences on hydroxyapatite, the RGD and flanking residues from osteopontin were fused to the C terminus. The fusion peptides bound tightly to hydroxyapatite, and the N15-PGRGDS peptide mediated the dose-dependent adhesion of Mo␣ v melanoma cells when immobilized on the hydroxyapatite surface. Experiments with an integrin-sorted Mo␣ v subpopulation demonstrated that the ␣ v ␤ 3 integrin was the primary receptor target for the fusion peptide. Solid state NMR experiments showed that the RGD portion of the hydrated fusion peptide is highly dynamic on the hydroxyapatite surface. This fusion peptide framework may thus provide a straightforward design for immobilizing bioactive sequences on hydroxyapatite for biomaterials, tissue engineering, and vaccine applications.

Elastomeric Osteoconductive Synthetic Scaffolds with Acquired Osteoinductivity Expedite the Repair of Critical Femoral Defects in Rats

“…2 Despite its high mineral content, this structural composite can withstand repetitive functional-compressive loads with excellent shape recovery under physiological conditions. 2 As a result of the high surface area of the nHA component and its intrinsic affinity for proteins and small molecule therapeutics, 3,4 FlexBone is also a suitable vehicle for delivering growth factors and antibiotics in a sustained and localized manner in vitro (Supplementary Fig. S1; Supplementary Data are available online at www.liebertonline.com/ten).…”

Modular Peptide Growth Factors for Substrate‐Mediated Stem Cell Differentiation

“…OCN, BSP) by engineering synthetic modular peptide molecules that bind to synthetic HA, yet remain capable of affecting cell adhesion. [2] This modular design approach has been used to promote cell adhesion to HA materials, which are now used in a wide range of common clinical orthopedic applications. However, previous studies have not yet extended this type of modular design strategy in order to non-covalently immobilize growth factors, which are capable of actively regulating stem cell phenotype.…”

Salivary Statherin Peptide-Binding Epitopes of Commensal and Potentially Infectious Actinomyces spp. Delineated by a Hybrid Peptide Construct

“…Recently a statherin-based hybrid fusion construct employing the high level of affinity of statherin for hydroxyapatite was found useful for leukocyte binding to peptides bearing the RGD epitope (10). The 15 N-terminal amino acids of statherin, including the two phosphoserines in positions 2 and 3, were fused to a test domain via a proline residue, which (through its conformational restraints) confers optimal presentation of the test epitope away from the hydroxyapatite surface.…”