title: Prion protein interaction with soil humic substances: environmental implications.
abstract: Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative disorders caused by prions. Animal TSE include scrapie in sheep and goats, and chronic wasting disease (CWD) in cervids. Effective management of scrapie in many parts of the world, and of CWD in North American deer population is complicated by the persistence of prions in the environment. After shedding from diseased animals, prions persist in soil, withstanding biotic and abiotic degradation. As soil is a complex, multi-component system of both mineral and organic components, it is important to understand which soil compounds may interact with prions and thus contribute to disease transmission. Several studies have investigated the role of different soil minerals in prion adsorption and infectivity; we focused our attention on the interaction of soil organic components, the humic substances (HS), with recombinant prion protein (recPrP) material. We evaluated the kinetics of recPrP adsorption, providing a structural and biochemical characterization of chemical adducts using different experimental approaches. Here we show that HS act as potent anti-prion agents in prion infected neuronal cells and in the amyloid seeding assays: HS adsorb both recPrP and prions, thus sequestering them from the prion replication process. We interpreted our findings as highly relevant from an environmental point of view, as the adsorption of prions in HS may affect their availability and consequently hinder the environmental transmission of prion diseases in ruminants.
authors.affiliation: Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Giachin
authors.affiliation: Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
authors.forename: Joanna
authors.initials: J
authors.lastname: Narkiewicz
authors.affiliation: Life Science Department, University of Trieste, Trieste, Italy.
authors.forename: Denis
authors.initials: D
authors.lastname: Scaini
authors.affiliation: Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
authors.forename: Ai Tran
authors.initials: AT
authors.lastname: Ngoc
authors.affiliation: Consiglio per la Ricerca e Sperimentazione in Agricoltura (CRA), Gorizia, Italy.
authors.forename: Alja
authors.initials: A
authors.lastname: Margon
authors.affiliation: Consiglio per la Ricerca e Sperimentazione in Agricoltura (CRA), Gorizia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Sequi
authors.affiliation: Consiglio per la Ricerca e Sperimentazione in Agricoltura (CRA), Gorizia, Italy.
authors.forename: Liviana
authors.initials: L
authors.lastname: Leita
authors.affiliation: Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Legname
mesh_terms: D000327:Adsorption; D000818:Animals; D002478:Cells, Cultured; D006812:Humic Substances; D051379:Mice; D011328:Prions / Q000737:chemistry*
chemical_list: D006812:Humic Substances; D011328:Prions