While animal prion diseases are a threat to human health, their zoonotic potential is generally inefficient because of interspecies prion transmission barriers. New animal models are required to provide an understanding of these prion transmission barriers and to assess the zoonotic potential of animal prion diseases. To address this goal, we generated Drosophila transgenic for human or nonhuman primate prion protein (PrP) and determined their susceptibility to known pathogenic prion diseases, namely varient Creutzfeldt-Jakob disease (vCJD) and classical bovine spongiform encephalopathy (BSE), and that with unknown pathogenic potential, namely chronic wasting disease (CWD).
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2023
Pollution by heavy metals is a threat to public health because of the adverse effects on multiple organ systems including the brain. Here, we used the African giant rat (AGR) as a novel sentinel host to assess the effect of heavy metal accumulation and consequential neuropathology upon the brain. For this study, AGR were collected from distinct geographical regions of Nigeria: the rain forest region of south-west Nigeria (Ibadan), the central north of Nigeria (Abuja), and in oil-polluted areas of south Nigeria (Port-Harcourt).
View Article and Find Full Text PDFA defining characteristic of mammalian prions is their capacity for self-sustained propagation. Theoretical considerations and experimental evidence suggest that prion propagation is modulated by cell-autonomous and non-autonomous modifiers. Using a novel quantitative phospholipase protection assay (QUIPPER) for high-throughput prion measurements, we performed an arrayed genome-wide RNA interference (RNAi) screen aimed at detecting cellular host-factors that can modify prion propagation.
View Article and Find Full Text PDFThe metazoan Hsp70 disaggregase protects neurons from proteotoxicity that arises from the accumulation of misfolded protein aggregates. Hsp70 and its co-chaperones disassemble and extract polypeptides from protein aggregates for refolding or degradation. The effectiveness of the chaperone system decreases with age and leads to accumulation rather than removal of neurotoxic protein aggregates.
View Article and Find Full Text PDFPrion diseases are fatal neurodegenerative conditions of humans and various vertebrate species that are transmissible between individuals of the same or different species. A novel infectious moiety referred to as a prion is considered responsible for transmission of these conditions. Prion replication is believed to be the cause of the neurotoxicity that arises during prion disease pathogenesis.
View Article and Find Full Text PDFPrions are transmissible protein pathogens most reliably detected by a bioassay in a suitable host, typically mice. However, the mouse bioassay is slow and cumbersome, and relatively insensitive to low titers of prion infectivity. Prions can be detected biochemically in vitro by the protein misfolding cyclic amplification (PMCA) technique, which amplifies disease-associated prion protein but does not detect bona fide prion infectivity.
View Article and Find Full Text PDFPrion diseases are fatal transmissible neurodegenerative conditions of humans and animals that arise through neurotoxicity induced by PrP misfolding. The cellular and molecular mechanisms of prion-induced neurotoxicity remain undefined. Understanding these processes will underpin therapeutic and control strategies for human and animal prion diseases, respectively.
View Article and Find Full Text PDFAtypical/Nor98 scrapie (AS) is a prion disease of small ruminants. Currently there are no efficient measures to control this form of prion disease, and, importantly, the zoonotic potential and the risk that AS might represent for other farmed animal species remains largely unknown. In this study, we investigated the capacity of AS to propagate in bovine PrP transgenic mice.
View Article and Find Full Text PDFThe aggregation of the prion protein (PrP) plays a key role in the development of prion diseases. In the past decade, a similar process has been associated with other proteins, such as Aβ, tau, and α-synuclein, which participate in other neurodegenerative diseases. It is increasingly recognized that the small oligomeric species of aggregates can play an important role in the development of prion diseases.
View Article and Find Full Text PDFPrions are believed to propagate when an assembly of prion protein (PrP) enters a cell and replicates to produce two or more fibrils, leading to an exponential increase in PrP aggregate number with time. However, the molecular basis of this process has not yet been established in detail. Here, we use single-aggregate imaging to study fibril fragmentation and elongation of individual murine PrP aggregates from seeded aggregation in vitro.
View Article and Find Full Text PDFMammalian prions propagate by template-directed misfolding and aggregation of normal cellular prion related protein PrPC as it converts into disease-associated conformers collectively referred to as PrPSc. Mammalian species may be permissive for prion disease because these hosts have co-evolved specific co-factors that assist PrPC conformational change and prion propagation. We have tested this hypothesis by examining whether faithful prion propagation occurs in the normally PrPC-null invertebrate host Drosophila melanogaster.
View Article and Find Full Text PDFPrion diseases are fatal neurodegenerative conditions of humans and vertebrate species. The transmissible prion agent is a novel infectious particle composed principally of PrP , an abnormal isomer of the normal host protein PrP . The only reliable method to detect mammalian prion infectivity is by bioassay, invariably in a vertebrate host.
View Article and Find Full Text PDFInherited human prion diseases, such as fatal familial insomnia (FFI) and familial Creutzfeldt-Jakob disease (fCJD), are associated with autosomal dominant mutations in the human prion protein gene and accumulation of PrP, an abnormal isomer of the normal host protein PrP, in the brain of affected individuals. PrP is the principal component of the transmissible neurotoxic prion agent. It is important to identify molecular pathways and cellular processes that regulate prion formation and prion-induced neurotoxicity.
View Article and Find Full Text PDFIn pursuit of a tractable bioassay to assess blood prion infectivity, we have generated prion protein (PrP) transgenic Drosophila, which show a neurotoxic phenotype in adulthood after exposure to exogenous prions at the larval stage. Here, we determined the sensitivity of ovine PrP transgenic Drosophila to ovine prion infectivity by exposure of these flies to a dilution series of scrapie-infected sheep brain homogenate. Ovine PrP transgenic Drosophila showed a significant neurotoxic response to dilutions of 10 to 10 of the original scrapie-infected sheep brain homogenate.
View Article and Find Full Text PDFProtein misfolding neurodegenerative diseases arise through neurotoxicity induced by aggregation of host proteins. These conditions include Alzheimer's disease, Huntington's disease, Parkinson's disease, motor neuron disease, tauopathies and prion diseases. Collectively, these conditions are a challenge to society because of the increasing aged population and through the real threat to human food security by animal prion diseases.
View Article and Find Full Text PDFPolymorphisms in ovine PrP at amino acid residues 141 and 154 are associated with susceptibility to ovine prion disease: Leu141Arg154 with classical scrapie and Phe141Arg154 and Leu141His154 with atypical scrapie. Classical scrapie is naturally transmissible between sheep, whereas this may not be the case with atypical scrapie. Critical amino acid residues will determine the range or stability of structural changes within the ovine prion protein or its functional interaction with potential cofactors, during conversion of PrPC to PrPSc in these different forms of scrapie disease.
View Article and Find Full Text PDFPrion diseases are fatal transmissible neurodegenerative diseases of various mammalian species. Central to these conditions is the conversion of the normal host prion protein PrP(C) into the abnormal prion conformer PrP(Sc). Mature PrP(C) is attached to the plasma membrane by a glycosylphosphatidylinositol anchor, whereas during biosynthesis and metabolism cytosolic and secreted forms of the protein may arise.
View Article and Find Full Text PDFPrion diseases are characterized by a conformational change in the normal host protein PrPC. While the majority of mature PrPC is tethered to the plasma membrane by a glycosylphosphatidylinositol anchor, topological variants of this protein can arise during its biosynthesis. Here we have generated Drosophila transgenic for cytosolic ovine PrP in order to investigate its toxic potential in flies in the absence or presence of exogenous ovine prions.
View Article and Find Full Text PDFNanopores can be used to detect and analyze single molecules in solution. We have used glass nanopores made by laser-assisted capillary-pulling, as a high-throughput and low cost method, to detect a range of label-free proteins: lysozyme, avidin, IgG, β-lactoglobulin, ovalbumin, bovine serum albumin (BSA), and β-galactosidase in solution. Furthermore, we show for the first time solid state nanopore measurements of mammalian prion protein, which in its abnormal form is associated with transmissible spongiform encephalopathies.
View Article and Find Full Text PDFDrosophila have emerged as a model system to study mammalian neurodegenerative diseases. In the present study we have generated Drosophila transgenic for ovine PrP (prion protein) to begin to establish an invertebrate model of ovine prion disease. We generated Drosophila transgenic for polymorphic variants of ovine PrP by PhiC31 site-specific germ-line transformation under expression control by the bi-partite GAL4/UAS (upstream activating sequence) system.
View Article and Find Full Text PDFPrion diseases are fatal transmissible neurodegenerative diseases of humans and various vertebrate species. In their natural hosts these conditions are characterised by prolonged incubation times prior to the onset of clinical signs of terminal disease. Accordingly, tractable models of mammalian prion disease are required in order to better understand the mechanisms of prion replication and prion-induced neurotoxicity.
View Article and Find Full Text PDFOvine prion strains have typically been identified by their transmission properties, which include incubation time and lesion profile, in wild type mice. The existence of scrapie isolates that do not propagate in wild type mice, defined here as "poor" transmitters, are problematic for conventional prion strain typing studies as no incubation time or neuropathology can be recorded. This may arise because of the presence of an ovine prion strain within the original inoculum that does not normally cross the species barrier into wild type mice or the presence of a low dose of an infectious ovine prion strain that does.
View Article and Find Full Text PDFThe infectious agent associated with prion diseases such as ovine scrapie shows strain diversity. Ovine prion strains have typically been identified by their transmission properties in wild-type mice. However, strain typing of ovine scrapie isolates in wild-type mice may not reveal properties of the infectious prion agent as they exist in the original host.
View Article and Find Full Text PDFThe normal cellular form of the prion protein PrP(C) is a glycosylphosphatidylinositol-linked cell-surface glycoprotein expressed primarily by cells of the nervous and immune systems. There is evidence to suggest that PrP(C) is involved in cell signalling and cellular homeostasis. We have investigated the immune composition of peripheral lymphoid tissue in PrP-/-, wild-type, tg19 and tga20 strains of mice, which express 0, 1-, 3-5- and 4-7-fold higher levels of PrP(C), respectively, relative to wild-type mice.
View Article and Find Full Text PDF