Axon degeneration: context defines distinct pathways

Curr Opin Neurobiol. 2016 Aug;39:108-15. doi: 10.1016/j.conb.2016.05.002. Epub 2016 May 16.

Abstract

Axon degeneration is an essential part of development, plasticity, and injury response and has been primarily studied in mammalian models in three contexts: 1) Axotomy-induced Wallerian degeneration, 2) Apoptosis-induced axon degeneration (axon apoptosis), and 3) Axon pruning. These three contexts dictate engagement of distinct pathways for axon degeneration. Recent advances have identified the importance of SARM1, NMNATs, NAD+ depletion, and MAPK signaling in axotomy-induced Wallerian degeneration. Interestingly, apoptosis-induced axon degeneration and axon pruning have many shared mechanisms both in signaling (e.g. DLK, JNKs, GSK3α/β) and execution (e.g. Puma, Bax, caspase-9, caspase-3). However, the specific mechanisms by which caspases are activated during apoptosis versus pruning appear distinct, with apoptosis requiring Apaf-1 but not caspase-6 while pruning requires caspase-6 but not Apaf-1.

Publication types

  • Review

MeSH terms

  • Animals
  • Apoptosis / physiology
  • Axons / enzymology
  • Axons / metabolism*
  • Caspases / metabolism
  • Wallerian Degeneration / physiopathology

Substances

  • Caspases