Activation of c-Jun and ATF-2 in primate motor cranial nerve nuclei is not associated with apoptosis following axotomy

Geoffrey P. Colby, Alexander L. Coon, E. Sander Connolly, Richard T. Ambron

Research output: Contribution to journalArticlepeer-review

Abstract

Nerve transection induces complex changes in gene regulation and expression that can have profound phenotypic effects on the fate of axotomized neurons. The transcription factors c-Jun and ATF-2 (activating transcription factor-2) are components of a regulatory network that mediates survival, regeneration, and apoptosis following axotomy in rodents. The activation and function of c-Jun and ATF-2 after nerve injury have not been examined in primates. Using a novel model of cranial nerve injury in baboons, we have examined the temporality of c-Jun activation (phosphorylation) in cranial nerve (CN) III and CN VI neurons and ATF-2 activation in CN VI neurons at 2, 4, and 9 days post-injury by immunohistochemistry. Furthermore, we have addressed whether the activation of these factors is associated with apoptosis by the TUNEL assay. We report that activated c-Jun is present in CN III and CN VI neurons ipsilateral to axotomy at 2, 4, and 9 days post-injury, but not in neurons contralateral to injury. Additionally, CN VI neurons ipsilateral to injury at 4 and 9 days contain activated ATF-2. Furthermore, no evidence of TUNEL reactivity was observed in either nucleus, regardless of laterality, at any of the examined time points. These findings suggest that activation of both c-Jun and ATF-2 does not mediate apoptosis in axotomized primate CN III and CN VI neurons at time points up to 9 days. This report serves as a basic inquiry into the neuronal response to cranial nerve injury in primates.

Original languageEnglish (US)
Pages (from-to)57-65
Number of pages9
JournalExperimental Neurology
Volume194
Issue number1
DOIs
StatePublished - Jul 1 2005

Keywords

  • ATF-2
  • Abducens
  • Apoptosis
  • Axotomy
  • Cranial nerve
  • Oculomotor
  • Primate
  • c-Jun

ASJC Scopus subject areas

  • Neurology
  • Developmental Neuroscience

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