A single day of 5-azacytidine exposure during development induces neurodegeneration in neonatal mice and neurobehavioral deficits in adult mice

Physiol Behav. 2016 Dec 1;167:16-27. doi: 10.1016/j.physbeh.2016.08.036. Epub 2016 Sep 1.

Abstract

The present study was undertaken to evaluate the immediate and long-term effects of a single-day exposure to 5-Azacytidine (5-AzaC), a DNA methyltransferase inhibitor, on neurobehavioral abnormalities in mice. Our findings suggest that the 5-AzaC treatment significantly inhibited DNA methylation, impaired extracellular signal-regulated kinase (ERK1/2) activation and reduced expression of the activity-regulated cytoskeleton-associated protein (Arc). These events lead to the activation of caspase-3 (a marker for neurodegeneration) in several brain regions, including the hippocampus and cortex, two brain areas that are essential for memory formation and memory storage, respectively. 5-AzaC treatment of P7 mice induced significant deficits in spatial memory, social recognition, and object memory in adult mice and deficits in long-term potentiation (LTP) in adult hippocampal slices. Together, these data demonstrate that the inhibition of DNA methylation by 5-AzaC treatment in P7 mice causes neurodegeneration and impairs ERK1/2 activation and Arc protein expression in neonatal mice and induces behavioral abnormalities in adult mice. DNA methylation-mediated mechanisms appear to be necessary for the proper maturation of synaptic circuits during development, and disruption of this process by 5-AzaC could lead to abnormal cognitive function.

Keywords: DNA methylation; Developing brain; Epigenetics; Methyltransferase; Neuronal loss; Synaptic plasticity.

Publication types

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

MeSH terms

  • Animals
  • Animals, Newborn
  • Azacitidine / toxicity*
  • Brain / drug effects
  • Brain / metabolism
  • Brain Diseases / chemically induced*
  • DNA Methylation / drug effects
  • DNA Methylation / genetics
  • Disease Models, Animal
  • Enzyme Inhibitors / toxicity*
  • Female
  • Gene Expression Regulation, Developmental / drug effects
  • Gene Expression Regulation, Developmental / genetics
  • Hippocampus / cytology
  • Hippocampus / drug effects
  • Long-Term Potentiation / drug effects
  • Long-Term Potentiation / genetics
  • Male
  • Maze Learning / drug effects
  • Memory Disorders / etiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neurodegenerative Diseases / chemically induced*
  • Neurodegenerative Diseases / pathology
  • Phosphopyruvate Hydratase / metabolism
  • Receptor, Cannabinoid, CB1 / deficiency
  • Receptor, Cannabinoid, CB1 / genetics
  • Signal Transduction / drug effects
  • Social Behavior

Substances

  • Enzyme Inhibitors
  • Receptor, Cannabinoid, CB1
  • Phosphopyruvate Hydratase
  • Azacitidine