(579d) Modulating Endothelial Cell Response to Crosslinked Artificial Extracellular Matrix Proteins

A family of artificial extracellular matrix (aECM) proteins was designed for soft-tissue engineering applications. These proteins consist of i) elastin-based structural repeats to confer mechanical properties, ii) fibronectin cell-binding domains to promote cell adhesion, and iii) lysine residues that serve as crosslinking sites. Previous work established that cell-binding domain choice and context (i.e. amino acid choice more than 14 residues away from the cell-binding domain sequence) can be used to alter cell adhesion and spreading response to aECM proteins. This study demonstrates that ligand density of crosslinked aECM films provides another tool for controlling cell response.

We previously showed that cells adhere specifically to both the RGD and CS5 cell-binding sequences in adsorbed aECM proteins. This work focuses on aECM-RGD, a variant that contains the RGD sequence, and aECM-RDG, a negative control protein that contains a scrambled cell-binding domain. Covalent attachment of poly(ethylene glycol) (PEG) to crosslinked aECM substrates decreased nonspecific cell adhesion to aECM-RDG-PEG but did not preclude sequence-specific adhesion of endothelial cells to aECM-RGD-PEG. To alter cellular responses, ligand density was varied by mixing aECM-RGD and aECM-RDG prior to crosslinking. Increasing the RGD density resulted in more robust adhesion and spreading responses but did not affect cell motility rates. Control of cell-binding domain density in aECM proteins can thus be used to modulate cell adhesion and spreading, and will serve as an important design tool as these materials are developed further for use in surgery, tissue engineering and regenerative medicine.