title: Enhanced integrin mediated signaling and cell cycle progression on fibronectin mimetic peptide amphiphile monolayers.
abstract: In recent years, a variety of biomimetic constructs have emerged which mimic the bioactive sequences found in the natural extracellular matrix (ECM) proteins such as fibronectin (FN) that promote cell adhesion as well as proliferation on artificially functionalized interfaces. Much interest lies in investigating the ability of the ECM mimetic materials in regulating a number of vital cell functions including differentiation, gene expression, migration, and proliferation. A peptide amphiphile PR_b containing both the cell adhesive GRGDSP and synergistic PHSRN peptide sequences was developed in our group that was shown to support enhanced cell proliferation and ECM FN secretion as compared to GRGDSP and FN functionalized interfaces. In this study, we have investigated the binding affinity of the PR_b peptide ligand with the FN cell surface receptor, the α(5)β(1) integrin. We compared PR_b functionalized surfaces with FN and BSA coated surfaces and GRGDSP functionalized surfaces in terms of promoting intracellular signaling cascades that are essential for enhanced cellular activity. Specifically, we studied the phosphorylation of focal adhesion kinase (FAK) at tyrosine residues Y397 and Y576 and the formation of cyclin D1, both of which are intracellular markers of integrin mediated attachment of cells, signaling pathways, and progression of cell cycle. FAK and cyclin D1 encourage enhanced cell proliferation, differentiation, and gene expression. Our results show that the PR_b peptide ligand has a specific and strong binding affinity for the α(5)β(1) integrin with a dissociation constant of 76.3 ± 6.3 nM. The PR_b peptide ligands supported enhanced FAK phosphorylation activity and increased cyclin D1 formation as compared to the widely used GRGDSP ligand, the native protein FN (positive control), and BSA nonadhesive surfaces (negative control). These results encourage the use of the FN mimetic PR_b peptide in functionalizing biomaterials for potential tissue engineering and therapeutic applications.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States.
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Shroff
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Pearce
authors.forename: Efrosini
authors.initials: E
authors.lastname: Kokkoli
mesh_terms: D000595:Amino Acid Sequence; D040761:Biomimetic Materials; D032701:Biomimetics; D002453:Cell Cycle; D019938:Cyclin D1 / Q000378:metabolism; D005353:Fibronectins / Q000737:chemistry* / Q000378:metabolism*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism
chemical_list: C530104:CCND1 protein, human; D005353:Fibronectins; D039081:Integrin alpha5beta1; D009842:Oligopeptides; D010446:Peptide Fragments; D010455:Peptides; C495978:prolyl-histidyl-seryl-arginyl-asparagine; D019938:Cyclin D1; D012710:Serum Albumin, Bovine; D014443:Tyrosine; C058161:glycyl-arginyl-glycyl-aspartyl-seryl-proline; D051416:Focal Adhesion Protein-Tyrosine Kinases