Differential effects of the PI3K/AKT pathway on antler stem cells for generation and regeneration of antlers in vitro.

Understanding the role of the PI3K/AKT pathway in regulating basic antler stem cell parameters and angiogenesis may provide an insight into the mechanisms underlying mammalian appendage development. The present study took multiple approaches in vitro to investigate the effects of the PI3K/AKT pathway on antler stem cells. By addition of LY294002, proliferation rate of the antlerogenic periosteum (AP) cells was decreased significantly (p<0.01), while the proliferation rate of the pedicle periosteum (PP) cells decreased to a lesser extent; the cytoskeleton of the AP cells was essentially collapsed; and the PP cells significantly shrunken. By addition of LY294002 or KU-0063794, formation of networking tubular structures from HUVECs in the AP or PP cell conditioned medium was significantly inhibited; whereas, expression level of VEGF-B mRNA in the AP or PP cells was decreased by the former, and increased by the latter significantly. Therefore, the results suggest that the PI3K/AKT pathway is involved in proliferation and differentiation of the AP and the PP cells, and plays a more important role in the former than in the latter.