NAD+ depletion is necessary and sufficient for poly(ADP-ribose) polymerase-1-mediated neuronal death

J Neurosci. 2010 Feb 24;30(8):2967-78. doi: 10.1523/JNEUROSCI.5552-09.2010.

Abstract

Poly(ADP-ribose)-1 (PARP-1) is a key mediator of cell death in excitotoxicity, ischemia, and oxidative stress. PARP-1 activation leads to cytosolic NAD(+) depletion and mitochondrial release of apoptosis-inducing factor (AIF), but the causal relationships between these two events have been difficult to resolve. Here, we examined this issue by using extracellular NAD(+) to restore neuronal NAD(+) levels after PARP-1 activation. Exogenous NAD(+) was found to enter neurons through P2X(7)-gated channels. Restoration of cytosolic NAD(+) by this means prevented the glycolytic inhibition, mitochondrial failure, AIF translocation, and neuron death that otherwise results from extensive PARP-1 activation. Bypassing the glycolytic inhibition with the metabolic substrates pyruvate, acetoacetate, or hydroxybutyrate also prevented mitochondrial failure and neuron death. Conversely, depletion of cytosolic NAD(+) with NAD(+) glycohydrolase produced a block in glycolysis inhibition, mitochondrial depolarization, AIF translocation, and neuron death, independent of PARP-1 activation. These results establish NAD(+) depletion as a causal event in PARP-1-mediated cell death and place NAD(+) depletion and glycolytic failure upstream of mitochondrial AIF release.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Apoptosis Inducing Factor / drug effects
  • Apoptosis Inducing Factor / metabolism
  • Cell Death / physiology
  • Cell Respiration / drug effects
  • Cell Respiration / physiology
  • Cells, Cultured
  • Energy Metabolism / drug effects
  • Energy Metabolism / physiology
  • Glycolysis / drug effects
  • Glycolysis / physiology
  • Mice
  • Mice, Knockout
  • Mitochondria / drug effects
  • Mitochondria / enzymology
  • Mitochondrial Diseases / drug therapy
  • Mitochondrial Diseases / enzymology
  • Mitochondrial Diseases / physiopathology
  • NAD / deficiency*
  • NAD / pharmacology
  • Nerve Degeneration / enzymology*
  • Nerve Degeneration / physiopathology*
  • Neurons / drug effects
  • Neurons / enzymology*
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases / genetics
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Protein Transport / drug effects
  • Protein Transport / physiology
  • Receptors, Purinergic P2 / drug effects
  • Receptors, Purinergic P2 / metabolism
  • Receptors, Purinergic P2X7

Substances

  • Apoptosis Inducing Factor
  • P2rx7 protein, mouse
  • Receptors, Purinergic P2
  • Receptors, Purinergic P2X7
  • NAD
  • Parp1 protein, mouse
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases