title: KDEL-tagged anti-prion intrabodies impair PrP lysosomal degradation and inhibit scrapie infectivity.
abstract: Transmissible spongiform encephalopathy or prion diseases are fatal neurodegenerative disorders characterized by the conversion of the cellular prion protein (PrPC) into the infectious scrapie isoform (PrPSc). We have recently demonstrated that anti-prion intrabodies targeted to the lumen of the endoplasmic reticulum provide a simple and effective means to inhibit the transport of PrPC to the cell surface. Here, we report that they completely block the traffic of mature full-length PrPC molecules, impair prion lysosomal degradation, and interfere with the early phase of scrapie formation. Since anti-prion intrabodies efficiently block PrPSc accumulation in vitro, we investigated whether they could also antagonize scrapie infectivity in vivo. We found that mice intracerebrally injected with KDEL-8H4-NGF-differentiated PC12 cells infected with scrapie neither develop scrapie clinical signs nor brain damage. Furthermore, no protease-resistant PrPSc is detectable in brains of inoculated animals. These results indicate that anti-prion intrabody strategy may be effective against prion infection.
authors.affiliation: Department of Neuroscience and Laboratory of Clinical Biochemistry, University of Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Vetrugno
authors.forename: Alessio
authors.initials: A
authors.lastname: Cardinale
authors.forename: Ilaria
authors.initials: I
authors.lastname: Filesi
authors.forename: Sonia
authors.initials: S
authors.lastname: Mattei
authors.forename: Man-Sun
authors.initials: MS
authors.lastname: Sy
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pocchiari
authors.forename: Silvia
authors.initials: S
authors.lastname: Biocca
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology*; D007424:Intracellular Fluid / Q000276:immunology; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D009842:Oligopeptides / Q000378:metabolism*; D016716:PC12 Cells; D018621:PrPC Proteins / Q000378:metabolism*; D018620:PrPSc Proteins / Q000472:pathogenicity*; D011328:Prions / Q000276:immunology*; D021382:Protein Sorting Signals; D051381:Rats; D012608:Scrapie / Q000635:transmission*
chemical_list: D000906:Antibodies; D009842:Oligopeptides; D018621:PrPC Proteins; D018620:PrPSc Proteins; D011328:Prions; D021382:Protein Sorting Signals; C073762:lysyl-aspartyl-glutamyl-leucine