Inhibition of P53-related apoptosis had no effect on PrPSc accumulation and prion disease incubation time

Results from several laboratories indicate that apoptosis via the P53 pathway is involved in prion disease pathogenesis. Prion diseases, among them scrapie and BSE, are a group of fatal neurodegenerative disorders associated with the conversion of PrPC to PrPSc, its conformational abnormal isoform. In this work, we tested whether an established anti-apoptotic reagent, PFT, which has been shown in different systems to inhibit P53 activity, can delay the outbreak of prion disease in infected animals. Our findings indicate that although PFT efficiently reduced caspase 3 expression in brains from scrapie sick hamsters, as well as inhibited PrPSc accumulation in cell culture, it had no effect on disease incubation time or PrPSc accumulation in vivo. We conclude that the P53 dependent apoptosis may not be an obligatory mechanism for prion disease-induced cell death.