Article

Maternal care and DNA methylation of a glutamic acid decarboxylase 1 promoter in rat hippocampus.

Sackler Program for Epigenetics and Developmental Psychobiology at McGill University, Douglas Mental Health University Institute, McGill University, Montreal, Quebec H4H 1R3, Canada.
Journal of Neuroscience (impact factor: 7.11). 09/2010; 30(39):13130-7. DOI:10.1523/JNEUROSCI.1039-10.2010 pp.13130-7
Source: PubMed

ABSTRACT Parenting and the early environment influence the risk for various psychopathologies. Studies in the rat suggest that variations in maternal care stably influence DNA methylation, gene expression, and neural function in the offspring. Maternal care affects neural development, including the GABAergic system, the function of which is linked to the pathophysiology of diseases including schizophrenia and depression. Postmortem studies of human schizophrenic brains have revealed decreased forebrain expression of glutamic acid decarboxylase 1 (GAD1) accompanied by increased methylation of a GAD1 promoter. We examined whether maternal care affects GAD1 promoter methylation in the hippocampus of adult male offspring of high and low pup licking/grooming (high-LG and low-LG) mothers. Compared with the offspring of low-LG mothers, those reared by high-LG dams showed enhanced hippocampal GAD1 mRNA expression, decreased cytosine methylation, and increased histone 3-lysine 9 acetylation (H3K9ac) of the GAD1 promoter. DNA methyltransferase 1 expression was significantly higher in the offspring of low- compared with high-LG mothers. Pup LG increases hippocampal serotonin (5-HT) and nerve growth factor-inducible factor A (NGFI-A) expression. Chromatin immunoprecipitation assays revealed enhanced NGFI-A association with and H3K9ac of the GAD1 promoter in the hippocampus of high-LG pups after a nursing bout. Treatment of hippocampal neuronal cultures with either 5-HT or an NGFI-A expression plasmid significantly increased GAD1 mRNA levels. The effect of 5-HT was blocked by a short interfering RNA targeting NGFI-A. These results suggest that maternal care influences the development of the GABA system by altering GAD1 promoter methylation levels through the maternally induced activation of NGFI-A and its association with the GAD1 promoter.

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Keywords

altering GAD1 promoter methylation levels
 
Chromatin immunoprecipitation assays
 
cytosine methylation
 
environment influence
 
GABA system
 
GABAergic system
 
GAD1 mRNA levels
 
GAD1 promoter methylation
 
glutamic acid decarboxylase 1
 
high-LG mothers
 
high-LG pups
 
hippocampal GAD1 mRNA expression
 
hippocampal neuronal cultures
 
human schizophrenic brains
 
low pup licking/grooming
 
low-LG mothers
 
maternal care influences
 
maternal care stably influence DNA methylation
 
nursing bout
 
various psychopathologies