Dissociation of recombinant prion autocatalysis from infectivity

Noble, Geoffrey P.; Supattapone, Surachai

doi:10.1080/19336896.2015.1123843

Cited by 2 publications

(2 citation statements)

References 30 publications

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“…In the future, our system can be used to assay the neurotoxicity of various PrP Sc ‐like forms generated by in vitro conversion reactions. As some of these species are infectious, while others are not , the results obtained will allow analysis of the structural relationship between the toxic and infectious properties of misfolded PrP. Thus far, all of our toxicity studies have been carried out with the RML strain of scrapie prions.…”

Section: A Novel Neuronal Culture System To Study Prion Neurotoxicitymentioning

confidence: 99%

Prion neurotoxicity

2019

Brain Pathology

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Although the mechanisms underlying prion propagation and infectivity are now well established, the processes accounting for prion toxicity and pathogenesis have remained mysterious. These processes are of enormous clinical relevance as they hold the key to identification of new molecular targets for therapeutic intervention. In this review, we will discuss two broad areas of investigation relevant to understanding prion neurotoxicity. The first is the use of in vitro experimental systems that model key events in prion pathogenesis. In this context, we will describe a hippocampal neuronal culture system we developed that reproduces the earliest pathological alterations in synaptic morphology and function in response to PrP Sc . This system has allowed us to define a core synaptotoxic signaling pathway involving the activation of NMDA and AMPA receptors, stimulation of p38 MAPK phosphorylation and collapse of the actin cytoskeleton in dendritic spines. The second area concerns a striking and unexpected phenomenon in which certain structural manipulations of the PrP C molecule itself, including introduction of N-terminal deletion mutations or binding of antibodies to C-terminal epitopes, unleash powerful toxic effects in cultured cells and transgenic mice. We will describe our studies of this phenomenon, which led to the recognition that it is related to the induction of large, abnormal ionic currents by the structurally altered PrP molecules. Our results suggest a model in which the flexible N-terminal domain of PrP C serves as a toxic effector which is regulated by intramolecular interactions with the globular C-terminal domain. Taken together, these two areas of study have provided important clues to underlying cellular and molecular mechanisms of prion neurotoxicity. Nevertheless, much remains to be done on this next frontier of prion science.

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Section: A Novel Neuronal Culture System To Study Prion Neurotoxicitymentioning

confidence: 99%

Prion neurotoxicity

2019

Brain Pathology

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“…One potential explanation is the inherent differences in the PMCA and RT-QuIC assays used in the experiments. Investigations of the amyloid products produced by PMCA sonication have described a diverse population of conformers, including small oligomers, which may be more infectious than large aggregates (32,52). Examinations of RT-QuIC products have demonstrated amyloid fibrils; however, full characterization of the sizes and types of fibrils remains to be done (35,53,54).…”

Section: Figmentioning

confidence: 99%

Endogenous Brain Lipids Inhibit Prion Amyloid Formation In Vitro

Hoover

Davenport

Henderson

et al. 2017

J Virol

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The normal cellular prion protein (PrP C ) resides in detergent-resistant outer membrane lipid rafts in which conversion to the pathogenic misfolded form is believed to occur. Once misfolding occurs, the pathogenic isoform polymerizes into highly stable amyloid fibrils. In vitro assays have demonstrated an intimate association between prion conversion and lipids, specifically phosphatidylethanolamine, which is a critical cofactor in the formation of synthetic infectious prions. In the current work, we demonstrate an alternative inhibitory function of lipids in the prion conversion process as assessed in vitro by real-time quaking-induced conversion (RTQuIC). Using an alcohol-based extraction technique, we removed the lipid content from chronic wasting disease (CWD)-infected white-tailed deer brain homogenates and found that lipid extraction enabled RT-QuIC detection of CWD prions in a 2-log 10 -greater concentration of brain sample. Conversely, addition of brain-derived lipid extracts to CWD prion brain or lymph node samples inhibited amyloid formation in a dose-dependent manner. Subsequent lipid analysis demonstrated that this inhibitory function was restricted to the polar lipid fraction in brain. We further investigated three phospholipids commonly found in lipid membranes, phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol, and found all three similarly inhibited RT-QuIC. These results demonstrating polar-lipid, and specifically phospholipid, inhibition of prion-seeded amyloid formation highlight the diverse roles lipid constituents may play in the prion conversion process. IMPORTANCE Prion conversion is likely influenced by lipid interactions, given the location of normal prion protein (PrP C ) in lipid rafts and lipid cofactors generating infectious prions in in vitro models. Here, we use real-time quaking-induced conversion (RT-QuIC) to demonstrate that endogenous brain polar lipids can inhibit prionseeded amyloid formation, suggesting that prion conversion is guided by an environment of proconversion and anticonversion lipids. These experiments also highlight the applicability of RT-QuIC to identify potential therapeutic inhibitors of prion conversion.

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Dissociation of recombinant prion autocatalysis from infectivity

Cited by 2 publications

References 30 publications

Prion neurotoxicity

Prion neurotoxicity

Endogenous Brain Lipids Inhibit Prion Amyloid Formation In Vitro

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