In psychosis, cortical interneurons overexpress DNA-methyltransferase 1

Marin Veldic, Alessandro Guidotti, Ekrem Maloku, John M. Davis, Erminio Costa

Research output: Contribution to journalArticlepeer-review

220 Scopus citations


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 GAD 67 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.

Original languageEnglish (US)
Pages (from-to)2152-2157
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number6
StatePublished - Feb 8 2005


  • Antipsychotics
  • Bipolar disorder
  • Glutamic acid decarboxylase
  • Schizophrenia
  • Valproate

ASJC Scopus subject areas

  • General


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