| 1. |
- Lau, Heather H. C., et al.
(author)
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The G51D SNCA mutation generates a slowly progressive alpha-synuclein strain in early-onset Parkinson's disease
- 2023
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In: Acta neuropathologica communications. - : BioMed Central (BMC). - 2051-5960. ; 11:1
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Journal article (peer-reviewed)abstract
- Unique strains of a-synuclein aggregates have been postulated to underlie the spectrum of clinical and pathological presentations seen across the synucleinopathies. Whereas multiple system atrophy (MSA) is associated with a predominance of oligodendroglial a-synuclein inclusions, a-synuclein aggregates in Parkinson's disease (PD) preferentially accumulate in neurons. The G51D mutation in the SNCA gene encoding a-synuclein causes an aggressive, early-onset form of PD that exhibits clinical and neuropathological traits reminiscent of both PD and MSA. To assess the strain characteristics of G51D PD a-synuclein aggregates, we performed propagation studies in M83 transgenic mice by intracerebrally inoculating patient brain extracts. The properties of the induced a-synuclein aggregates in the brains of injected mice were examined using immunohistochemistry, a conformational stability assay, and by performing a-synuclein seed amplification assays. Unlike MSA-injected mice, which developed a progressive motor phenotype, G51D PD-inoculated animals remained free of overt neurological illness for up to 18 months post-inoculation. However, a subclinical synucleinopathy was present in G51D PD-inoculated mice, characterized by the accumulation of a-synuclein aggregates in restricted regions of the brain. The induced a-synuclein aggregates in G51D PD-injected mice exhibited distinct properties in a seed amplification assay and were much more stable than those present in mice injected with MSA extract, which mirrored the differences observed between human MSA and G51D PD brain samples. These results suggest that the G51D SNCA mutation specifies the formation of a slowly propagating a-synuclein strain that more closely resembles a-synuclein aggregates associated with PD than MSA.
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| 2. |
- Walsh, Daniel J., et al.
(author)
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Anti-prion drugs do not improve survival in novel knock-in models of inherited prion disease
- 2024
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In: PLoS Pathogens. - : PUBLIC LIBRARY SCIENCE. - 1553-7366 .- 1553-7374. ; 20:4
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Journal article (peer-reviewed)abstract
- Prion diseases uniquely manifest in three distinct forms: inherited, sporadic, and infectious. Wild-type prions are responsible for the sporadic and infectious versions, while mutant prions cause inherited variants like fatal familial insomnia (FFI) and familial Creutzfeldt-Jakob disease (fCJD). Although some drugs can prolong prion incubation times up to four-fold in rodent models of infectious prion diseases, no effective treatments for FFI and fCJD have been found. In this study, we evaluated the efficacy of various anti-prion drugs on newly-developed knock-in mouse models for FFI and fCJD. These models express bank vole prion protein (PrP) with the pathogenic D178N and E200K mutations. We applied various drug regimens known to be highly effective against wild-type prions in vivo as well as a brain-penetrant compound that inhibits mutant PrPSc propagation in vitro. None of the regimens tested (Anle138b, IND24, Anle138b + IND24, cellulose ether, and PSCMA) significantly extended disease-free survival or prevented mutant PrPSc accumulation in either knock-in mouse model, despite their ability to induce strain adaptation of mutant prions. Our results show that anti-prion drugs originally developed to treat infectious prion diseases do not necessarily work for inherited prion diseases, and that the recombinant sPMCA is not a reliable platform for identifying compounds that target mutant prions. This work underscores the need to develop therapies and validate screening assays specifically for mutant prions, as well as anti-prion strategies that are not strain-dependent. We treated two mouse models of inherited prion disease with a variety of drug treatments, including several which have been previously shown to be highly effective against infectious prion diseases and another that biochemically inhibits the formation of mutant prion proteins in a test tube assay. Surprisingly none of the treatments improved lifespans in the either mouse model even though several treatments changed the distribution pattern of prion pathology in the brains of treated mice. Our results show that alternative strategies are needed to develop treatments for inherited prion diseases.
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