Hippocampal disruptions of synaptic and astrocyte metabolism are primary events of early amyloid pathology in the 5xFAD mouse model of Alzheimer’s disease

Jens V. Andersen, Niels H. Skotte, Sofie K. Christensen, Filip S. Polli, Mohammad Shabani, Kia H. Markussen, Henriette Haukedal, Emil W. Westi, Marta Diaz-delCastillo, Ramon C. Sun, Kristi A. Kohlmeier, Arne Schousboe, Matthew S. Gentry, Heikki Tanila, Kristine K. Freude, Blanca I. Aldana, Matthias Mann, Helle S. Waagepetersen

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Alzheimer’s disease (AD) is an unremitting neurodegenerative disorder characterized by cerebral amyloid-β (Aβ) accumulation and gradual decline in cognitive function. Changes in brain energy metabolism arise in the preclinical phase of AD, suggesting an important metabolic component of early AD pathology. Neurons and astrocytes function in close metabolic collaboration, which is essential for the recycling of neurotransmitters in the synapse. However, this crucial metabolic interplay during the early stages of AD development has not been sufficiently investigated. Here, we provide an integrative analysis of cellular metabolism during the early stages of Aβ accumulation in the cerebral cortex and hippocampus of the 5xFAD mouse model of AD. Our electrophysiological examination revealed an increase in spontaneous excitatory signaling in the 5xFAD hippocampus. This hyperactive neuronal phenotype coincided with decreased hippocampal tricarboxylic acid (TCA) cycle metabolism mapped by stable 13C isotope tracing. Particularly, reduced astrocyte TCA cycle activity and decreased glutamine synthesis led to hampered neuronal GABA synthesis in the 5xFAD hippocampus. In contrast, the cerebral cortex of 5xFAD mice displayed an elevated capacity for oxidative glucose metabolism, which may suggest a metabolic compensation in this brain region. We found limited changes when we explored the brain proteome and metabolome of the 5xFAD mice, supporting that the functional metabolic disturbances between neurons and astrocytes are early primary events in AD pathology. In addition, synaptic mitochondrial and glycolytic function was selectively impaired in the 5xFAD hippocampus, whereas non-synaptic mitochondrial function was maintained. These findings were supported by ultrastructural analyses demonstrating disruptions in mitochondrial morphology, particularly in the 5xFAD hippocampus. Collectively, our study reveals complex regional and cell-specific metabolic adaptations in the early stages of amyloid pathology, which may be fundamental for the progressing synaptic dysfunctions in AD.

Original languageEnglish
Article number954
JournalCell Death and Disease
Volume12
Issue number11
DOIs
StatePublished - Nov 2021

Bibliographical note

Funding Information:
The Scholarship of Peter & Emma Thomsen is gratefully acknowledged for personal financial support to J.V.A. The National Council of Research (Brazil) is acknowledged for the fellowship provided to F.S.P.

Funding Information:
This study was financially supported by Alzheimer-forskningsfonden (H.S.W. and K.F.), Grosserer L. F. Foghts Fond (J.V.A.), Augustinus Fonden (H.S.W.: 18-1624), the Lundbeck Foundation (J.V.A.: R333-2019-1244), Hørslev Fonden (H.S.W.: 203866), National Institutes of Health (M.S.G.: R35NS116824, R.C.S.: R01AG066653) and the Novo Nordisk Foundation (M.M.: NNF14CC0001 & NNF15CC0001, K.K.F.: NNF18OC0052369).

Publisher Copyright:
© 2021, The Author(s).

ASJC Scopus subject areas

  • Immunology
  • Cellular and Molecular Neuroscience
  • Cell Biology
  • Cancer Research

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