RESUMO
Prion diseases such as Creutzfeldt-Jakob disease (CJD) are incurable and rapidly fatal neurodegenerative diseases. Because prion protein (PrP) is necessary for prion replication but dispensable for the host, we developed the PrP-FRET-enabled high throughput assay (PrP-FEHTA) to screen for compounds that decrease PrP expression. We screened a collection of drugs approved for human use and identified astemizole and tacrolimus, which reduced cell-surface PrP and inhibited prion replication in neuroblastoma cells. Tacrolimus reduced total cellular PrP levels by a nontranscriptional mechanism. Astemizole stimulated autophagy, a hitherto unreported mode of action for this pharmacophore. Astemizole, but not tacrolimus, prolonged the survival time of prion-infected mice. Astemizole is used in humans to treat seasonal allergic rhinitis in a chronic setting. Given the absence of any treatment option for CJD patients and the favorable drug characteristics of astemizole, including its ability to cross the blood-brain barrier, it may be considered as therapy for CJD patients and for prophylactic use in familial prion diseases. Importantly, our results validate PrP-FEHTA as a method to identify antiprion compounds and, more generally, FEHTA as a unique drug discovery platform.
Assuntos
Astemizol/farmacologia , Autofagia/efeitos dos fármacos , Descoberta de Drogas/métodos , Avaliação Pré-Clínica de Medicamentos/métodos , Doenças Priônicas/tratamento farmacológico , Príons/metabolismo , Tacrolimo/farmacologia , Animais , Astemizol/uso terapêutico , Western Blotting , Linhagem Celular Tumoral , Transferência Ressonante de Energia de Fluorescência/métodos , Ensaios de Triagem em Larga Escala/métodos , Humanos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Prion strain identification has been hitherto achieved using time-consuming incubation time determinations in one or more mouse lines and elaborate neuropathological assessment. In the present work, we make a detailed study of the properties of PrP-overproducing Tga20 mice. We show that in these mice the four prion strains examined are rapidly and faithfully amplified and can subsequently be discriminated by a cell-based procedure, the Cell Panel Assay.