title: Epigenetic modifications of GABAergic interneurons are associated with the schizophrenia-like phenotype induced by prenatal stress in mice.
abstract: Human studies suggest that a variety of prenatal stressors are related to high risk for cognitive and behavioral abnormalities associated with psychiatric illness (Markham and Koenig, 2011). Recently, a downregulation in the expression of GABAergic genes (i.e., glutamic acid decarboxylase 67 and reelin) associated with DNA methyltransferase (DNMT) overexpression in GABAergic neurons has been regarded as a characteristic phenotypic component of the neuropathology of psychotic disorders (Guidotti et al., 2011). Here, we characterized mice exposed to prenatal restraint stress (PRS) in order to study neurochemical and behavioral abnormalities related to development of schizophrenia in the adult. Offspring born from non-stressed mothers (control mice) showed high levels of DNMT1 and 3a mRNA expression in the frontal cortex at birth, but these levels progressively decreased at post-natal days (PND) 7, 14, and 60. Offspring born from stressed mothers (PRS mice) showed increased levels of DNMTs compared to controls at all time-points studied including at birth and at PND 60. Using GAD67-GFP transgenic mice, we established that, in both control and PRS mice, high levels of DNMT1 and 3a were preferentially expressed in GABAergic neurons of frontal cortex and hippocampus. Importantly, the overexpression of DNMT in GABAergic neurons was associated with a decrease in reelin and GAD67 expression in PRS mice in early and adult life. PRS mice also showed an increased binding of DNMT1 and MeCP2, and an increase in 5-methylcytosine and 5-hydroxymethylcytosine in specific CpG-rich regions of the reelin and GAD67 promoters. Thus, the epigenetic changes in PRS mice are similar to changes observed in the post-mortem brains of psychiatric patients. Behaviorally, adult PRS mice showed hyperactivity and deficits in social interaction, prepulse inhibition, and fear conditioning that were corrected by administration of valproic acid (a histone deacetylase inhibitor) or clozapine (an atypical antipsychotic with DNA-demethylation activity). Taken together, these data show that prenatal stress in mice induces abnormalities in the DNA methylation network and in behaviors indicative of a schizophrenia-like phenotype. Thus, PRS mice may be a valid model for the investigation of new drugs for schizophrenia treatment targeting DNA methylation. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
authors.affiliation: The Psychiatric Institute, Department of Psychiatry, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA. fmatrisciano@hotmail.com
authors.forename: Francesco
authors.initials: F
authors.lastname: Matrisciano
authors.forename: Patricia
authors.initials: P
authors.lastname: Tueting
authors.forename: Ishani
authors.initials: I
authors.lastname: Dalal
authors.forename: Bashkim
authors.initials: B
authors.lastname: Kadriu
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Grayson
authors.forename: John M
authors.initials: JM
authors.lastname: Davis
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Nicoletti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Guidotti
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism; D059330:GABAergic Neurons / Q000378:metabolism*; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism; D007395:Interneurons / Q000378:metabolism*; D051379:Mice; D009043:Motor Activity / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000091042:Reelin Protein; D012149:Restraint, Physical; D012559:Schizophrenia / Q000209:etiology / Q000235:genetics* / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D012919:Social Behavior; D013312:Stress, Physiological / Q000502:physiology*; D013315:Stress, Psychological / Q000150:complications / Q000235:genetics* / Q000378:metabolism
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D000091042:Reelin Protein; C491786:Dnmt2 protein, mouse; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; C000619381:Dnmt1 protein, mouse; C000717127:RELN protein, human; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1