title: Inhibition of cholesterol recycling impairs cellular PrP(Sc) propagation.
abstract: The infectious agent in prion diseases consists of an aberrantly folded isoform of the cellular prion protein (PrP(c)), termed PrP(Sc), which accumulates in brains of affected individuals. Studies on prion-infected cultured cells indicate that cellular cholesterol homeostasis influences PrP(Sc) propagation. Here, we demonstrate that the cellular PrP(Sc) content decreases upon accumulation of cholesterol in late endosomes, as induced by NPC-1 knock-down or treatment with U18666A. PrP(c) trafficking, lipid raft association, and membrane turnover are not significantly altered by such treatments. Cellular PrP(Sc) formation is not impaired, suggesting that PrP(Sc) degradation is increased by intracellular cholesterol accumulation. Interestingly, PrP(Sc) propagation in U18666A-treated cells was partially restored by overexpression of rab 9, which causes redistribution of cholesterol and possibly of PrP(Sc) to the trans-Golgi network. Surprisingly, rab 9 overexpression itself reduced cellular PrP(Sc) content, indicating that PrP(Sc) production is highly sensitive to alterations in dynamics of vesicle trafficking.
authors.affiliation: Institute of Virology, Prion Research Group, Technische Universität München, Trogerstr. 30, 81675 Munich, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Gilch
authors.forename: Christian
authors.initials: C
authors.lastname: Bach
authors.forename: Gloria
authors.initials: G
authors.lastname: Lutzny
authors.forename: Ina
authors.initials: I
authors.lastname: Vorberg
authors.forename: Hermann M
authors.initials: HM
authors.lastname: Schätzl
mesh_terms: D000736:Androstenes / Q000494:pharmacology; D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology; D001921:Brain / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D000077296:Niemann-Pick C1 Protein; D018620:PrPSc Proteins / Q000235:genetics / Q000378:metabolism*; D017096:Prion Diseases / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D014162:Transfection; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D021601:trans-Golgi Network / Q000187:drug effects / Q000378:metabolism
chemical_list: D000736:Androstenes; D000924:Anticholesteremic Agents; D047908:Intracellular Signaling Peptides and Proteins; D000077296:Niemann-Pick C1 Protein; C106831:Npc1 protein, mouse; D018620:PrPSc Proteins; D011506:Proteins; D049452:Green Fluorescent Proteins; C006261:3-beta-(2-(diethylamino)ethoxy)androst-5-en-17-one; D002784:Cholesterol; C544263:rab9 protein, mouse; D020691:rab GTP-Binding Proteins