A major challenge in regenerative medicine is to establish a cell-matrix technology able to facilitate the recovery of damaged heart tissues. Collagen, the main structural protein in connective tissues, is often chosen as the material to produce a cell supporting structure. However, material properties of collagen matrices matching that of the myocardium are obtained after a NHS/EDC treatment, resulting in a dramatic loss of cell adhesion. Our aim is to restore cell reactivity on collagen films by coupling synthetic ligands able to regulate cell behaviour. An inventive synthetic pathway for covalent linkage of such ligands to a collagen structure was developed, ensuring the interaction between cells and the material, thus directing cell growth and differentiation. Recent work in our lab has involved the synthesis of triple helical peptides (THPs) that mimic collagen binding sites. THPs possess a generic GXX’GEX’’ central pattern with binding properties surrounded by GPP triplets, maintaining the assembly in an active triple helical conformation. Amongst the identified sequences, GFOGER has drawn particular attention as one of the major binding site for collagen binding integrins (including α2β1 and α1β1) and was chosen as a model motif for collagen film coating. Besides synthesis optimisation using microwave chemistry, the crosslinking of THP strands was investigated in order to stabilize the triple helical structure. Moreover, a covalent linkage to permanently immobilize peptides on collagen is required to avoid elution. Diazirine, a photoreactive group, was thus grafted on the N-terminal side of crosslinked THPs. This enabled us to set up a protocol for coating THPs on collagen films upon long wavelength UV activation. First trials using recombinant proteins of the α2β1 integrin binding site showed significant increase in the attachment of the targeted receptor on collagen films coated with THPs. Binding, spreading and proliferation of cells on collagen decorated with THPs was also assessed using HT1080 and Rugli cell lines. Results showed significant enhancement in cell activity for peptide decorated collagen films in a α1β1 and α2β1 integrin dependent manner. The on-going work focuses on the chemical synthesis of new ligands for collagen binding cells, in order to control cell growth and differentiation by targeting specific receptors.

Development of collagen films coated with synthetic photoreactive peptides that support cardiovascular repair and regeneration

249th National Meeting (2015)

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