title: Amyloid-β Oligomers Interact with Neurexin and Diminish Neurexin-mediated Excitatory Presynaptic Organization.
abstract: Alzheimer's disease (AD) is characterized by excessive production and deposition of amyloid-beta (Aβ) proteins as well as synapse dysfunction and loss. While soluble Aβ oligomers (AβOs) have deleterious effects on synapse function and reduce synapse number, the underlying molecular mechanisms are not well understood. Here we screened synaptic organizer proteins for cell-surface interaction with AβOs and identified a novel interaction between neurexins (NRXs) and AβOs. AβOs bind to NRXs via the N-terminal histidine-rich domain (HRD) of β-NRX1/2/3 and alternatively-spliced inserts at splicing site 4 of NRX1/2. In artificial synapse-formation assays, AβOs diminish excitatory presynaptic differentiation induced by NRX-interacting proteins including neuroligin1/2 (NLG1/2) and the leucine-rich repeat transmembrane protein LRRTM2. Although AβOs do not interfere with the binding of NRX1β to NLG1 or LRRTM2, time-lapse imaging revealed that AβO treatment reduces surface expression of NRX1β on axons and that this reduction depends on the NRX1β HRD. In transgenic mice expressing mutated human amyloid precursor protein, synaptic expression of β-NRXs, but not α-NRXs, decreases. Thus our data indicate that AβOs interact with NRXs and that this interaction inhibits NRX-mediated presynaptic differentiation by reducing surface expression of axonal β-NRXs, providing molecular and mechanistic insights into how AβOs lead to synaptic pathology in AD.
authors.affiliation: Synapse Development and Plasticity Research Unit, Institut de recherches cliniques de Montréal, Montréal, Québec, H2W 1R7, Canada.|Integrated Program in Neuroscience, McGill University, Montréal, Québec, H3A 2B4, Canada.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Synapse Development and Plasticity Research Unit, Institut de recherches cliniques de Montréal, Montréal, Québec, H2W 1R7, Canada.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tanabe
authors.affiliation: Synapse Development and Plasticity Research Unit, Institut de recherches cliniques de Montréal, Montréal, Québec, H2W 1R7, Canada.|Integrated Program in Neuroscience, McGill University, Montréal, Québec, H3A 2B4, Canada.
authors.forename: Alfred Kihoon
authors.initials: AK
authors.lastname: Lee
authors.affiliation: Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, Québec, H3A 2B4, Canada.
authors.forename: Edith
authors.initials: E
authors.lastname: Hamel
authors.affiliation: Synapse Development and Plasticity Research Unit, Institut de recherches cliniques de Montréal, Montréal, Québec, H2W 1R7, Canada.|Department of Medicine, Université de Montréal, Montréal, Québec, Canada, H3T 1J4; Division of Experimental Medicine, McGill University, Montréal, Québec, H3A 0G4, Canada.
authors.forename: Hideto
authors.initials: H
authors.lastname: Takahashi
mesh_terms: D017398:Alternative Splicing; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001369:Axons / Q000378:metabolism; D019556:COS Cells; D015816:Cell Adhesion Molecules, Neuronal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004195:Disease Models, Animal; D015870:Gene Expression; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017729:Presynaptic Terminals / Q000502:physiology*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D055366:Synaptic Potentials
chemical_list: D016229:Amyloid beta-Peptides; D015816:Cell Adhesion Molecules, Neuronal; C561320:LRRTM2 protein, human; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins