Prolyl hydroxylase inhibitors delay neuronal cell death caused by trophic factor deprivation

J Neurochem. 2007 Dec;103(5):1897-906. doi: 10.1111/j.1471-4159.2007.04873.x. Epub 2007 Aug 30.

Abstract

Nerve growth factor (NGF) serves a critical survival-promoting function for developing sympathetic neurons. Following removal of NGF, sympathetic neurons undergo apoptosis characterized by the activation of c-Jun N-terminal kinases (JNKs), up-regulation of BH3-only proteins including BcL-2-interacting mediator of cell death (BIM)(EL), release of cytochrome c from mitochondria, and activation of caspases. Here we show that two small-molecule prolyl hydroxylase inhibitors frequently used to activate hypoxia-inducible factor (HIF) - ethyl 3,4-dihydroxybenzoic acid (DHB) and dimethyloxalylglycine (DMOG) - can inhibit apoptosis caused by trophic factor deprivation. Both DHB and DMOG blocked the release of cytochrome c from mitochondria after NGF withdrawal, whereas only DHB blocked c-Jun up-regulation and phosphorylation. DHB, but not DMOG, also attenuated the induction of BIM(EL) in NGF-deprived neurons, suggesting a possible mechanism whereby DHB could inhibit cytochrome c release. DMOG, on the other hand, was substantially more effective at stabilizing HIF-2alpha and inducing expression of the HIF target gene hexokinase 2 than was DHB. Thus, while HIF prolyl hydroxylase inhibitors can delay cell death in NGF-deprived neurons, they do so through distinct mechanisms that, at least in the case of DHB, are partly independent of HIF stabilization.

Publication types

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

MeSH terms

  • Amino Acids, Dicarboxylic / pharmacology*
  • Animals
  • Animals, Newborn
  • Cell Death / drug effects
  • Cells, Cultured
  • Cytochromes c / metabolism
  • Embryo, Mammalian
  • Enzyme Inhibitors / pharmacology*
  • Gene Expression Regulation / drug effects
  • Hydroxybenzoates / pharmacology*
  • Mitochondria / drug effects
  • Nerve Growth Factor / deficiency*
  • Neurons / drug effects*
  • Procollagen-Proline Dioxygenase / antagonists & inhibitors
  • Proto-Oncogene Proteins c-jun / metabolism
  • Rats
  • Superior Cervical Ganglion / cytology

Substances

  • Amino Acids, Dicarboxylic
  • Enzyme Inhibitors
  • Hydroxybenzoates
  • Proto-Oncogene Proteins c-jun
  • ethyl protocatechuate
  • Cytochromes c
  • Nerve Growth Factor
  • Procollagen-Proline Dioxygenase
  • oxalylglycine