In vivo study on the survival of neural stem cells transplanted into the rat brain with a collagen hydrogel that incorporates laminin-derived polypeptides.

Poor viability of cells transplanted into the brain has been the critical problem associated with stem cell-based therapy for Parkinson's disease. To overcome this problem, a collagen hydrogel incorporating an integrin-binding protein complex was prepared and used as a carrier for neural stem cells. The protein complex consisted of two polypeptides containing the G3 domain of a laminin α1 chain and the C-terminal oligopeptide of a laminin γ1 chain. These polypeptides were fused with α-helical segments which spontaneously formed a coiled-coil heterodimer and with the collagen-binding peptide that facilitated the binding of the heterodimer to collagen networks. In this study, neural stem cells stably expressing the enhanced green fluorescent protein (EGFP) were suspended in the hydrogel and transplanted into the striatum of healthy rats. The viability of transplanted cells was evaluated by histological analysis and quantitative reverse-transcriptase polymerase chain reaction for EGFP mRNA present in the tissue explants. Our results showed that the collagen hydrogel incorporating the integrin-binding protein complex serves to improve the viability of neural stem cells (NSCs) in the early stage after transplantation into the striatum.