Chronic excitotoxin-induced axon degeneration in a compartmented neuronal culture model
journal contributionposted on 2023-05-17, 14:32 authored by Katherine SouthamKatherine Southam, Anna KingAnna King, Catherine BlizzardCatherine Blizzard, James VickersJames Vickers, Tracey DicksonTracey Dickson
Glutamate excitotoxicity is a major pathogenic process implicated in many neurodegenerative conditions, including AD (Alzheimer's disease) and following traumatic brain injury. Occurring predominantly from over-stimulation of ionotropic glutamate receptors located along dendrites, excitotoxic axonal degeneration may also occur in white matter tracts. Recent identification of axonal glutamate receptor subunits within axonal nanocomplexes raises the possibility of direct excitotoxic effects on axons. Individual neuronal responses to excitotoxicity are highly dependent on the complement of glutamate receptors expressed by the cell, and the localization of the functional receptors. To enable isolation of distal axons and targeted excitotoxicity, murine cortical neuron cultures were prepared in compartmented microfluidic devices, such that distal axons were isolated from neuronal cell bodies. Within the compartmented culture system, cortical neurons developed to relative maturity at 11 DIV (days in vitro) as demonstrated by the formation of dendritic spines and clustering of the presynaptic protein synaptophysin. The isolated distal axons retained growth cone structures in the absence of synaptic targets, and expressed glutamate receptor subunits. Glutamate treatment (100 ìM) to the cell body chamber resulted in widespread degeneration within this chamber and degeneration of distal axons in the other chamber. Glutamate application to the distal axon chamber triggered a lesser degree of axonal degeneration without degenerative changes in the untreated somal chamber. These data indicate that in addition to current mechanisms of indirect axonal excitotoxicity, the distal axon may be a primary target for excitotoxicity in neurodegenerative conditions.
Publication titleASN Neuro
Department/SchoolMenzies Institute for Medical Research
PublisherPortland Press Ltd.
Place of publication12 Roger St, London, WC1N 2JU, UK
Rights statementLicenced under Creative Commons Attribution Non-Commercial Licence (http://creativecommons.org/licenses/by-nc/2.5/ Copyright 2012 the authors.