Apoptosome dependent caspase-3 activation pathway is non-redundant and necessary for apoptosis in sympathetic neurons

Cell Death Differ. 2007 Mar;14(3):625-33. doi: 10.1038/sj.cdd.4402024. Epub 2006 Aug 25.

Abstract

Although sympathetic neurons are a well-studied model for neuronal apoptosis, the role of the apoptosome in activating caspases in these neurons remains debated. We find that the ability of sympathetic neurons to undergo apoptosis in response to nerve growth factor (NGF) deprivation is completely dependent on having an intact apoptosome pathway. Genetic deletion of Apaf-1, caspase-9, or caspase-3 prevents apoptosis after NGF deprivation, and importantly, allows these neurons to recover and survive long-term following readdition of NGF. The inability of caspase-3 deficient sympathetic neurons to undergo apoptosis is particularly striking, as apoptosis in dermal fibroblasts and cortical neurons proceeds even in the absence of caspase-3. Our results show that in contrast to dermal fibroblasts and cortical neurons, sympathetic neurons express no detectable levels of caspase-7. The strict requirement for an intact apoptosome, coupled with a lack of effector caspase redundancy, provides sympathetic neurons with a markedly increased control over their apoptotic pathway.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis
  • Apoptosomes / metabolism*
  • Apoptotic Protease-Activating Factor 1 / genetics
  • Caspase 3 / genetics
  • Caspase 3 / metabolism*
  • Caspase 7 / metabolism
  • Caspase 9 / genetics
  • Cells, Cultured
  • Cerebral Cortex / cytology
  • Cerebral Cortex / metabolism
  • Dermis / cytology
  • Dermis / drug effects
  • Dermis / metabolism
  • Enzyme Activation
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Gene Expression Regulation, Enzymologic*
  • Mice
  • Mice, Knockout
  • Nerve Growth Factor / pharmacology
  • Neurons / drug effects
  • Neurons / enzymology
  • Neurons / physiology*
  • Signal Transduction*
  • Sympathetic Nervous System / cytology
  • Sympathetic Nervous System / drug effects
  • Sympathetic Nervous System / enzymology*
  • Sympathetic Nervous System / metabolism

Substances

  • Apoptosomes
  • Apoptotic Protease-Activating Factor 1
  • Nerve Growth Factor
  • Caspase 3
  • Caspase 7
  • Caspase 9