Differential roles of Aβ processing in hypoxia-induced axonal damage.

Abstract

Axonopathy is a common and early phase in neurodegenerative and traumatic CNS diseases. Recent work suggests that amyloid β (Aβ) produced from amyloid precursor protein (APP) may be a critical downstream mediator of CNS axonopathy in CNS diseases, particularly those associated with hypoxia. We critically tested this hypothesis in an adult retinal explant system that preserves the three-dimensional organization of the retina while permitting direct imaging of two cardinal features of early-stage axonopathy: axonal structural integrity and axonal transport capacity. Using this system, we found via pharmacological inhibition and genetic deletion of APP that production of Aβ is a necessary step in structural compromise of retinal ganglion cell (RGC) axons induced by the disease-relevant stressor hypoxia. However, identical blockade of Aβ production was not sufficient to protect axons from associated hypoxia-induced reduction in axonal transport. Thus, Aβ mediates distinct facets of hypoxia-induced axonopathy and may represent a functionally selective pharmacological target for therapies directed against early-stage axonopathy in CNS diseases.

Authors

Christianson, Melissa G; Lo, Donald;

Keywords

  • Amyloid beta-Peptides/ metabolism
  • Amyloid beta-Protein Precursor/ deficiency
  • Amyloid beta-Protein Precursor/ genetics
  • Animals
  • Axons/ pathology
  • Cholera Toxin/ metabolism
  • Hypoxia/ metabolism
  • Hypoxia/ pathology
  • Imaging, Three-Dimensional
  • In Vitro Techniques
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Organ Culture Techniques
  • Peptide Fragments/ metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Retina/ cytology
  • Retinal Ganglion Cells/ cytology
  • Transfection
  • tau Proteins/ metabolism

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