Small-Molecule-Modified Surfaces Engage Cells through the αvβ3 Integrin

Integrins play myriad and vital roles in development and disease. They connect a cell with its surroundings and transmit chemical and mechanical signals across the plasma membrane to the cell's interior. Dissecting their roles in cell's interior. Dissecting their roles in cell behaviour is complicated by their overlapping ligand specificity and shared down stream signaling components. In principle, immobilized synthetic peptides can mimic extracellular matrix proteins by supporting integrin mediated adhesion, but most short peptide sequences lack selectivity for one integrin over others. In contrast, synthetic integrin antogonists can be highly selective. We hypothesized that this selectivity could be exploited if antagonists, when immobilized, could support cellular adhesion and activate signaling by engaging specific cell surface integrins. To investigate this possibility, we designed a bifunctional (RGD) based peptidomimetic for surface presentation. Our conjugate combines a high affinity integrin ligand with a biotin moiety; the former engages the alpha(v)beta(3) integrin, and the latter allows for presentation on streptavidin-coated surfaces. surfaces decorated with this ligand promote both cellular adhesion and integrin activation. Moreover, the selectivity of these surfaces for the alpha(v)beta(3) integrin can be exploited to capture a subset of cells from a mixed population. We anticipate that surfaces displaying highly selective small molecules ligands can reveal the contributions of specific integrin heterodimers to cell adhesion and signaling.