Self-assembling chimeric protein for the construction of biodegradable hydrogels capable of interaction with integrins expressed on neural stem/progenitor cells.

The poor survival of neural stem/progenitor cells following transplantation into the brain is the major problem limiting the effect of cell-based therapy for Parkinson's disease. To overcome this problem, we are involved in designing keratin-based hydrogels that serve as physical barriers to prevent the infiltration of inflammatory cells. Another feature of the hydrogels is to contain a polypeptide that promotes integrin-mediated cell adhesion. To construct such hydrogels, a chimeric protein consisting of an alpha-helical polypeptide and a globular domain derived from laminin was synthesized by means of recombinant DNA technology and coassembled with extracted keratins that form hydrogels through intermolecular coiled-coil association of alpha-helical segments. It was found that neurosphere-forming cells specifically adhered to the keratin-based composite hydrogel and actively proliferated at a high survival rate. These results suggested that the composite hydrogel provides microenvironments suitable for the survival and proliferation of neural progenitor cells.