J. Neurochem. (2010) 114, 362–373.
The normal cellular form of prion protein (PrPC) has been shown to exhibit a diverse range of biological activities. Several recent studies highlighted potential involvement of PrPC in embryogenesis or in regulating stem cell self-renewal and proliferation. In the current study, we employed human embryonic stem cells (hESCs) for assessing the potential role of prion protein in early human development. Here, we showed that treatment of hESCs with full-length recombinant PrP folded into an α-helical conformation similar to that of PrPC delayed the spontaneous differentiation of hESCs and helped to maintain their high proliferation activity during spontaneous differentiation. Considering that administration of α-rPrP was also found to down-regulate the expression of endogenous PrPC, the effects of α-rPrP were likely to be indirect, i.e. executed by endogenous PrPC. Together with previous observations, these work support the hypothesis that PrPC is involved in regulating self-renewal/differentiation status of stem cells including hESCs.