title: Engineering integrin-specific surfaces with a triple-helical collagen-mimetic peptide.
abstract: Integrin-mediated cell adhesion to extracellular matrix proteins anchors cells and triggers signals that direct cell function. The integrin alpha(2)beta(1) recognizes the glycine-phenylalanine-hydroxyproline-glycine-glutamate-arginine (GFOGER) motif in residues 502-507 of the alpha(1)(I) chain of type I collagen. Integrin recognition is entirely dependent on the triple-helical conformation of the ligand similar to that of native collagen. This study focuses on engineering alpha(2)beta(1)-specific bioadhesive surfaces by immobilizing a triple-helical collagen-mimetic peptide incorporating the GFOGER binding sequence onto model nonadhesive substrates. Circular dichroism spectroscopy verified that this peptide adopts a stable triple-helical conformation in solution. Passively adsorbed GFOGER-peptide exhibited dose-dependent HT1080 cell adhesion and spreading comparable to that observed on type I collagen. Subsequent antibody blocking conditions verified the involvement of integrin alpha(2)beta(1) in these adhesion events. Focal adhesion formation was observed by immunofluorescent staining for alpha(2)beta(1) and vinculin on MC3T3-E1 cells. Model functionalized surfaces then were engineered using three complementary peptide-tethering schemes. These peptide-functionalized substrates supported alpha(2)beta(1)-mediated cell adhesion and focal adhesion assembly. Our results suggest that this peptide is active in an immobilized conformation and may be applied as a surface modification agent to promote alpha(2)beta(1)-specific cell adhesion. Engineering surfaces that specifically target certain integrin-ligand interactions and signaling cascades provides a biomolecular strategy for optimizing cellular responses in biomaterials and tissue engineering applications.
authors.affiliation: Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, Georgia 30332-0363, USA.
authors.forename: Catherine D
authors.initials: CD
authors.lastname: Reyes
authors.forename: Andrés J
authors.initials: AJ
authors.lastname: García
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001360:Avidin; D001665:Binding Sites; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D002021:Buffers; D002448:Cell Adhesion; D002460:Cell Line; D002942:Circular Dichroism; D003094:Collagen / Q000737:chemistry*; D022001:Focal Adhesions; D006801:Humans; D038982:Integrin alpha2beta1 / Q000378:metabolism*; D008422:Materials Testing; D051379:Mice; D018716:Molecular Mimicry; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D000906:Antibodies; D001672:Biocompatible Materials; D002021:Buffers; D038982:Integrin alpha2beta1; D009842:Oligopeptides; D001360:Avidin; D003094:Collagen