1. Functional spreading of hyperexcitability induced by human and synthetic intracellular Aβ oligomers
- Author
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Eduardo J Fernández-Pérez, Christian Peters, Urmi Sengupta, María Paz Espinoza, Luis G. Aguayo, Jerome Epsztein, Nicolas O Riffo-Lepe, Romain Bourboulou, Braulio Muñoz, Caroline Filippi, Rakez Kayed, Denisse Bascuñán, Peter James Morgan, Universidad de Concepción - University of Concepcion [Chile], Institut de Neurobiologie de la Méditerranée [Aix-Marseille Université] (INMED - INSERM U1249), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM), George and Cynthia Mitchell Center for Neurodegenerative diseases, The University of Texas Medical Branch (UTMB), University of Texas Medical Branch at Galveston, Universidad de Concepción [Chile], and Institut National de la Santé et de la Recherche Médicale (INSERM)-Aix Marseille Université (AMU)
- Subjects
chemistry.chemical_compound ,chemistry ,nervous system ,In vivo ,Retrograde signaling ,Biophysics ,[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] ,AMPA receptor ,Hippocampal formation ,Beta (finance) ,Ex vivo ,Intracellular ,Nitric oxide - Abstract
BackgroundIntracellular amyloid-beta oligomers (iAβo) accumulation and neuronal hyperexcitability are two crucial events at early stages of Alzheimer’s disease (AD). However, to date, no mechanism linking them has been reported.MethodsHere, the effects of human AD brain-derived (h-iAβo) and synthetic (iAβo) peptides on synaptic currents and action potential (AP) firing were investigated in hippocampal neurons in vitro, ex vivo and in vivo.ResultsStarting from 500 pM, iAβo rapidly increased the frequency of synaptic currents and higher concentrations potentiated the AMPA receptor-mediated current. Both effects were PKC-dependent. Parallel recordings of synaptic currents and nitric oxide (NO)-related fluorescence changes indicated that the increased frequency, related to pre-synaptic release, was dependent on a NO-mediated retrograde signaling. Moreover, increased synchronization in NO production was also observed in neurons neighboring those dialyzed with iAβo, indicating that iAβo can increase network excitability at a distance. Current-clamp recordings suggested that iAβo increased neuronal excitability via AMPA-driven synaptic activity without altering membrane intrinsic properties.ConclusionThese results strongly indicate that iAβo causes functional spreading of hyperexcitability through a synaptic-driven mechanism and offer an important neuropathological significance to intracellular species in the initial stages of AD, which include brain hyperexcitability and seizures.
- Published
- 2020