title: 4-hydroxytamoxifen leads to PrPSc clearance by conveying both PrPC and PrPSc to lysosomes independently of autophagy.
abstract: Prion diseases are fatal neurodegenerative disorders involving the abnormal folding of a native cellular protein, named PrP(C), to a malconformed aggregation-prone state, enriched in beta sheet secondary structure, denoted PrP(Sc). Recently, autophagy has garnered considerable attention as a cellular process with the potential to counteract neurodegenerative diseases of protein aggregation such as Alzheimer's disease, Huntington's disease, and Parkinson's disease. Stimulation of autophagy by chemical compounds has also been shown to reduce PrP(Sc) in infected neuronal cells and prolong survival times in mouse models. Consistent with previous reports, we demonstrate that autophagic flux is increased in chronically infected cells. However, in contrast to recent findings we show that autophagy does not cause a reduction in scrapie burden. We report that in infected neuronal cells different compounds known to stimulate autophagy are ineffective in increasing autophagic flux and in reducing PrP(Sc). We further demonstrate that tamoxifen and its metabolite 4-hydroxytamoxifen lead to prion degradation in an autophagy-independent manner by diverting the trafficking of both PrP and cholesterol to lysosomes. Our data indicate that tamoxifen, a well-characterized, widely available pharmaceutical, may have applications in the therapy of prion diseases.
authors: Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, 25 rue du Docteur Roux, 75015 Paris, France.
authors: Ludovica
authors: L
authors: Marzo
authors: Zrinka
authors: Z
authors: Marijanovic
authors: Duncan
authors: D
authors: Browman
authors: Zeina
authors: Z
authors: Chamoun
authors: Anna
authors: A
authors: Caputo
authors: Chiara
authors: C
authors: Zurzolo
mesh_terms: D000818:Animals; D001343:Autophagy / Q000235:genetics; D000071193:Autophagy-Related Protein 7; D002460:Cell Line; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D018621:PrPC Proteins / Q000378:metabolism*; D018620:PrPSc Proteins / Q000378:metabolism*; D017096:Prion Diseases / Q000188:drug therapy* / Q000378:metabolism; D021381:Protein Transport; D059748:Proteolysis; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: C502661:Atg7 protein, mouse; D008869:Microtubule-Associated Proteins; D018621:PrPC Proteins; D018620:PrPSc Proteins; D034741:RNA, Small Interfering; D013629:Tamoxifen; C016601:afimoxifene; D000071193:Autophagy-Related Protein 7
keywords: Autophagy; Cholesterol; Lysosomal Degradation; OHT; PrPSc; TAM