SKIN-DERIVED NEURAL PRECURSORS AS A NOVEL REGENERATIVE THERAPY FOR ALZHEIMER’S DISEASE

Abstract

Skin-derived neural precursors (SKNs) are a novel source of autologous stem cells with the potential to overcome current issues impeding cell replacement therapy in Alzheimer's disease. While their capability for proliferation and neuronal differentiation in vitro has been well-established, and their therapeutic potential to restore neuronal connectivity demonstrated in aged rats, the migratory characteristics of SKNs have yet to be characterised and is therefore the focus of this study. SKNs were generated from adult canine skin biopsies using our unique 2-step culture method. In vitro chemotaxis migration assays were performed using the IBIDI microfluidic device to identify growth factors regulating SKN migration. To investigate in vivo migration, fluorescently-labelled SKNs were transplanted into the aged rat hippocampus, followed by histological analysis at three time points (day 3, 10 and 70 post-transplantation) to track their displacement, maturation and integration over time. In vitro, SKNs exhibited random movements in the absence of chemoattractants, as indicated by p>0.05 in the Rayleigh test for chemotactic potential and lack of moving direction. Conversely, directed migration was induced by concentration gradients of growth factors BDNF (p<0.0001), IGF-1 (p=0.0015) and VEGF (p=0.0056). Calculating the Euclidean distance travelled by SKNs showed the greatest migratory potential occurred when exposed to BDNF (p<0.05) and VEGF (p<0.001). In vivo, transplanted SKNs migrated extensively over large distances by day 7 post-transplantation, with a predilection to the CA1 hippocampal subregion. This data demonstrates a strong migratory potential of SKNs. More importantly, despite their non-neural origin, SKNs respond to chemotactic factors known to be important for migration of endogenous hippocampal neural precursor cells, suggesting a similar migratory mechanism to hippocampal neurogenesis. This is supported by in vivo results demonstrating canine SKNs migrate extensively following transplantation, differentiating into mature neurons and populating all hippocampal subregions. Ongoing studies will identify other molecular regulators of migration and fully characterize the patter of migration in vivo.