title: In psychosis, cortical interneurons overexpress DNA-methyltransferase 1.
abstract: Cortical DNA-methyltransferase 1 (DNMT1) is preferentially expressed in interneurons secreting GABA where it very likely contributes to promoter CpG island hypermethylation, thus causing a down-regulation of promoter functions. To consolidate and expand on previous findings that, in the cortex of schizophrenia (SZ) brains, glutamic acid decarboxylase 67 (GAD67) expression is down-regulated whereas that of DNMT1 is up-regulated, we studied both parameters in Brodmann's area (BA) 9 from the McLean 66 Cohort Collection (Harvard Brain Tissue Resource Center, Belmont, MA). In BA9 of SZ and bipolar disorder patients with psychosis, DNMT1 mRNA and protein expression preferentially increases in layer I, II, and IV interneurons, and this increase is paralleled by a decreased number of GAD67 mRNA-positive neurons. The increase in DNMT1 and the decrease in GAD67-expressing neurons were unrelated to postmortem interval, pH, RNA quality, or to the presence, dose, or duration of antipsychotic (APS) medication, with the exception of a subgroup of SZ patients treated with a combination of valproate and APS in which the expression of DNMT1 failed to change. The DNMT1 increase and the GAD67 decrease in BA9 interneurons are significant features of SZ and bipolar disorder with psychosis. Interestingly, the DNMT1 increase failed to occur when patients with psychosis received a combination of valproate and APS treatment but not APS monotherapy.
authors.affiliation: Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois, 1601 West Taylor Street, Chicago, IL 60612, USA.
authors.forename: Marin
authors.initials: M
authors.lastname: Veldic
authors.forename: Alessandro
authors.initials: A
authors.lastname: Guidotti
authors.forename: Ekrem
authors.initials: E
authors.lastname: Maloku
authors.forename: John M
authors.initials: JM
authors.lastname: Davis
authors.forename: Erminio
authors.initials: E
authors.lastname: Costa
mesh_terms: D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000627:therapeutic use; D015415:Biomarkers; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000166:cytology* / Q000201:enzymology*; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D018682:GABA Agents / Q000627:therapeutic use; D005786:Gene Expression Regulation; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D007395:Interneurons / Q000166:cytology / Q000201:enzymology*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D011618:Psychotic Disorders / Q000188:drug therapy / Q000201:enzymology*; D000091042:Reelin Protein; D012559:Schizophrenia / Q000188:drug therapy / Q000201:enzymology*; D012697:Serine Endopeptidases; D014635:Valproic Acid / Q000627:therapeutic use
chemical_list: D014150:Antipsychotic Agents; D015415:Biomarkers; D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D018682:GABA Agents; D007527:Isoenzymes; D009419:Nerve Tissue Proteins; D000091042:Reelin Protein; D014635:Valproic Acid; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; D012697:Serine Endopeptidases; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1