Cell death after spinal cord injury is exacerbated by rapid TNFα-induced trafficking of GluR2-lacking AMPARs to the plasma membrane

Adam R. Ferguson, Randolph N. Christensen, John C. Gensel, Brandon A. Miller, Fang Sun, Eric C. Beattie, Jacqueline C. Bresnahan, Michael S. Beattie

Research output: Contribution to journalArticlepeer-review

157 Scopus citations

Abstract

Glutamate, the major excitatory neurotransmitter in the CNS, is implicated in both normal neurotransmission and excitotoxicity. Numerous in vitro findings indicate that the ionotropic glutamate receptor, AMPAR, can rapidly traffic from intracellular stores to the plasma membrane, altering neuronal excitability. These receptor trafficking events are thought to be involved in CNS plasticity as well as learning and memory. AMPAR trafficking has recently been shown to be regulated by glial release of the proinflammatory cytokine tumor necrosis factor α (TNFα) in vitro. This has potential relevance to several CNS disorders, because many pathological states have a neuroinflammatory component involving TNFα. However, TNFα-induced trafficking of AMPARs has only been explored in primary or slice cultures and has not been demonstrated in preclinical models of CNS damage. Here, we use confocal and image analysis techniques to demonstrate that spinal cord injury (SCI) induces trafficking of AMPARs to the neuronal membrane. We then show that this effect is mimicked by nanoinjections of TNFα, which produces specific trafficking of GluR2-lacking receptors which enhance excitotoxicity. To determine if TNFα-induced trafficking affects neuronal cell death, we sequestered TNFα after SCI using a soluble TNFα receptor, and significantly reduced both AMPAR trafficking and neuronal excitotoxicity in the injury penumbra. The data provide the first evidence linking rapid TNFα-induced AMPAR trafficking to early excitotoxic secondary injury after CNS trauma in vivo, and demonstrate a novel way in which pathological states hijack mechanisms involved in normal synaptic plasticity to produce cell death.

Original languageEnglish (US)
Pages (from-to)11391-11400
Number of pages10
JournalJournal of Neuroscience
Volume28
Issue number44
DOIs
StatePublished - Oct 29 2008

Keywords

  • Excitotoxicity
  • Glia-neuron interactions
  • Inflammation
  • Neural-immune interaction
  • Neuroinflammation
  • Plasticity
  • Trauma

ASJC Scopus subject areas

  • Neuroscience(all)

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