A caspase cascade regulating developmental axon degeneration. Academic Article uri icon

Overview

abstract

  • Axon degeneration initiated by trophic factor withdrawal shares many features with programmed cell death, but many prior studies discounted a role for caspases in this process, particularly Caspase-3. Recently, Caspase-6 was implicated based on pharmacological and knockdown evidence, and we report here that genetic deletion of Caspase-6 indeed provides partial protection from degeneration. However, we find at a biochemical level that Caspase-6 is activated effectively only by Caspase-3 but not other "upstream" caspases, prompting us to revisit the role of Caspase-3. In vitro, we show that genetic deletion of Caspase-3 is fully protective against sensory axon degeneration initiated by trophic factor withdrawal, but not injury-induced Wallerian degeneration, and we define a biochemical cascade from prosurvival Bcl2 family regulators to Caspase-9, then Caspase-3, and then Caspase-6. Only low levels of active Caspase-3 appear to be required, helping explain why its critical role has been obscured in prior studies. In vivo, Caspase-3 and Caspase-6-knockout mice show a delay in developmental pruning of retinocollicular axons, thereby implicating both Caspase-3 and Caspase-6 in axon degeneration that occurs as a part of normal development.

authors

  • Simon, David J.
  • Weimer, Robby M
  • McLaughlin, Todd
  • Kallop, Dara
  • Stanger, Karen
  • Yang, Jing
  • O'Leary, Dennis D M
  • Hannoush, Rami N
  • Tessier-Lavigne, Marc

publication date

  • December 5, 2012

Research

keywords

  • Axons
  • Caspase 3
  • Caspase 6
  • Nerve Degeneration
  • Superior Colliculi

Identity

PubMed Central ID

  • PMC3532512

Scopus Document Identifier

  • 84870481635

Digital Object Identifier (DOI)

  • 10.1523/JNEUROSCI.3012-12.2012

PubMed ID

  • 23223278

Additional Document Info

volume

  • 32

issue

  • 49