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Identification of intraneuronal amyloid beta oligomers in locus coeruleus neurons of Alzheimer’s patients and their potential impact on inhibitory neurotransmitter receptors and neuronal excitability

Research output: Contribution to journalArticlepeer-review

  • Louise Kelly
  • Mohsen Seifi
  • Roulin Ma
  • Scott J. Mitchell
  • Uwe Rudolph
  • Kirsten L. Viola
  • William L. Klein
  • Jeremy J. Lambert
  • Professor Jerome Swinny
Aims: Amyloid β oligomers (AβO) are potent modulators of Alzheimer’s pathology, yet their impact on one of the earliest brain regions to exhibit signs of the condition, the locus coeruleus (LC), remains to be determined. Of particular importance is whether AβO impact the spontaneous excitability of LC neurons. This parameter determines brain‐wide noradrenaline (NA) release, and thus NA‐mediated brain functions, including cognition, emotion and immune function, which are all compromised in Alzheimer’s. Therefore, the aim of the study was to determine the expression profile of AβO in the LC of Alzheimer’s patients and to probe their potential impact on the molecular and functional correlates of LC excitability, using a mouse model of increased Aβ production (APP‐PSEN1).

Methods and Results: Immunohistochemistry and confocal microscopy, using AβO‐specific antibodies, confirmed LC AβO expression both intraneuronally and extracellularly in both Alzheimer’s and APP‐PSEN1 samples. Patch clamp electrophysiology recordings revealed that APP‐PSEN1 LC neuronal hyperexcitability accompanied this AβO expression profile, arising from a diminished inhibitory effect of GABA, due to impaired expression and function of the GABA‐A receptor (GABAAR) α3 subunit. This altered LC α3‐GABAAR expression profile overlapped with AβO expression in samples from both APP‐PSEN1 mice and Alzheimer’s patients. Finally, strychnine‐sensitive glycine receptors (GlyRs) remained resilient to Aβ‐induced changes and their activation reversed LC hyperexcitability.

Conclusions: The data suggest a close association between AβO and α3‐GABAARs in the LC of Alzheimer’s patients, and their potential to dysregulate LC activity, thereby contributing to the spectrum of pathology of the LC‐NA system in this condition.
Original languageEnglish
Article number0
JournalNeuropathology and Applied Neurobiology
Volume0
Early online date20 Dec 2020
DOIs
Publication statusEarly online - 20 Dec 2020

Documents

  • nan.12674

    Rights statement: This is the peer reviewed version of the following article: Kelly, L., Seifi, M., Ma, R., Mitchell, S.J., Rudolph, U., Viola, K.L., Klein, W.L., Lambert, J.J. and Swinny, J.D. (2021), Identification of intraneuronal amyloid beta oligomers in locus coeruleus neurons of Alzheimer’s patients and their potential impact on inhibitory neurotransmitter receptors and neuronal excitability. Neuropathol Appl Neurobiol. Ahead of print, which has been published in final form at https://doi.org/10.1111/nan.12674. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

    Accepted author manuscript (Post-print), 63.8 MB, PDF document

    Due to publisher’s copyright restrictions, this document is not freely available to download from this website until: 20/12/21

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