title: The reelin and GAD67 promoters are activated by epigenetic drugs that facilitate the disruption of local repressor complexes.
abstract: The epigenetic down-regulation of genes is emerging as a possible underlying mechanism of the GABAergic neuron dysfunction in schizophrenia. For example, evidence has been presented to show that the promoters associated with reelin and GAD67 are down-regulated as a consequence of DNA methyltransferase (DNMT)-mediated hypermethylation. Using neuronal progenitor cells to study this regulation, we have previously demonstrated that DNMT inhibitors coordinately increase reelin and GAD67 mRNAs. Here, we report that another group of epigenetic drugs, histone deacetylase (HDAC) inhibitors, activate these two genes with dose and time dependence comparable with that of DNMT inhibitors. In parallel, both groups of drugs decrease DNMT1, DNMT3A, and DNMT3B protein levels and reduce DNMT enzyme activity. Furthermore, induction of the reelin and GAD67 mRNAs is accompanied by the dissociation of repressor complexes containing all three DNMTs, MeCP2, and HDAC1 from the corresponding promoters and by increased local histone acetylation. Our data imply that drug-induced promoter demethylation is relevant for maximal activation of reelin and GAD67 transcription. The results suggest that HDAC and DNMT inhibitors activate reelin and GAD67 expression through similar mechanisms. Both classes of drugs attenuate, directly or indirectly, the enzymatic and transcriptional repressor activities of DNMTs and HDACs. These data provide a mechanistic rationale for the use of epigenetic drugs, individually or in combination, as a potential novel therapeutic strategy to alleviate deficits associated with schizophrenia.
authors.affiliation: Department of Psychiatry, The Psychiatric Institute, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: Marija
authors.initials: M
authors.lastname: Kundakovic
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Alessandro
authors.initials: A
authors.lastname: Guidotti
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Grayson
mesh_terms: D001549:Benzamides / Q000494:pharmacology; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003596:Cytosine / Q000502:physiology; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000502:physiology; D000090205:DNA Methyltransferase 3A; D004317:Doxorubicin; D044127:Epigenesis, Genetic; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism*; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D051783:Methyl-CpG-Binding Protein 2 / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects* / Q000235:genetics; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger; D000091042:Reelin Protein; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D000097584:DNA Methyltransferase 3B
chemical_list: D001549:Benzamides; D015816:Cell Adhesion Molecules, Neuronal; D003596:Cytosine; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D004317:Doxorubicin; D016326:Extracellular Matrix Proteins; D005968:Glutamate Decarboxylase; D056572:Histone Deacetylase Inhibitors; D051783:Methyl-CpG-Binding Protein 2; D009419:Nerve Tissue Proteins; D011725:Pyridines; D012333:RNA, Messenger; D000091042:Reelin Protein; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D000097584:DNA Methyltransferase 3B; C411744:DMAP1 protein, human; C000717967:DNMT3A protein, human; C118739:entinostat; C000619380:DNMT1 protein, human; C000717127:RELN protein, human; C402565:glutamate decarboxylase 1