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Acta Neuropathol Commun. 2018 Apr 3;6(1):26. doi: 10.1186/s40478-018-0529-x.

Prion-like propagation of β-amyloid aggregates in the absence of APP overexpression.

Author information

1
Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Tower, Rm. 4KD481, 60 Leonard Ave, Toronto, ON, M5T 2S8, Canada.
2
Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
3
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
4
Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Krembil Discovery Tower, Rm. 4KD481, 60 Leonard Ave, Toronto, ON, M5T 2S8, Canada. joel.watts@utoronto.ca.
5
Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada. joel.watts@utoronto.ca.

Abstract

The amyloid cascade hypothesis posits that the initiating event in Alzheimer's disease (AD) is the aggregation and deposition of the β-amyloid (Aβ) peptide, which is a proteolytic cleavage product of the amyloid precursor protein (APP). Mounting evidence suggests that the formation and spread of prion-like Aβ aggregates during AD may contribute to disease progression. Inoculation of transgenic mice that overexpress APP with pre-formed Aβ aggregates results in the prion-like induction of cerebral Aβ deposition. To determine whether Aβ deposition can also be induced when physiological APP levels are present in the brain, we inoculated AppNL-F mice, a knock-in model of AD that avoids potential artifacts associated with APP overexpression, with Aβ aggregates derived from the brains of AD patients or transgenic mice. In all cases, induced Aβ deposition was apparent in the corpus callosum, olfactory bulb, and meningeal blood vessels of inoculated mice at 130-150 days post-inoculation, whereas uninoculated and buffer-inoculated animals exhibited minimal or no Aβ deposits at these ages. Interestingly, despite being predominantly composed of protease-resistant Aβ42 aggregates, the induced parenchymal Aβ deposits were largely diffuse and were unreactive to an amyloid-binding dye. These results demonstrate that APP overexpression is not a prerequisite for the prion-like induction of cerebral Aβ deposition. Accordingly, spreading of Aβ deposition may contribute to disease progression in AD patients.

KEYWORDS:

Amyloid; Amyloid precursor protein; Aβ; Cerebral amyloid angiopathy; Knock-in mice; Prion-like transmission; Propagation

PMID:
29615128
PMCID:
PMC5883524
DOI:
10.1186/s40478-018-0529-x
[Indexed for MEDLINE]
Free PMC Article

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