Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.1.1.37 (DNA methyltransferase)
 4,983 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A recent report suggests that the down-regulation of reelin and glutamic acid decarboxylase (GAD(67)) mRNAs represents 2 of the more consistent findings thus far described in post-mortem material from schizophrenia (SZ) patients [reviewed in. Neurochemical markers for schizophrenia, bipolar disorder amd major depression in postmortem brains. Biol Psychiatry 57, 252-260]. To study mechanisms responsible for this down-regulation, we have analyzed the promoter of the human reelin gene. Collectively, our studies suggest that SZ is characterized by a gamma-amino butyric acid (GABA)-ergic neuron pathology presumably mediated by promoter hypermethylation facilitated by the over-expression of the methylating enzyme DNA methyltransferase (Dnmt) 1. Using transient expression assays, promoter deletions and co-transfection assays with various transcription factors, we have shown a clear synergistic action that is a critical component of the mechanism of the trans-activation process. Equally important is the observation that the reelin promoter is more heavily methylated in brain regions in patients diagnosed with SZ as compared to non-psychiatric control subjects [Grayson, D. R., Jia, X., Chen, Y., Sharma, R. P., Mitchell, C. P., & Guidotti, A., et al. (2005). Reelin promoter hypermethylation in schizophrenia. Proc Natl Acad Sci U S A 102, 9341-9346]. The combination of studies in cell lines and in animal models of SZ, coupled with data obtained from post-mortem human material provides compelling evidence that aberrant methylation may be part of a core dysfunction in this psychiatric disease. More interestingly, the hypermethylation concept provides a coherent mechanism that establishes a plausible link between the epigenetic misregulation of multiple genes that are affected in SZ and that collectively contribute to the associated symptomatology.
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PMID:The human reelin gene: transcription factors (+), repressors (-) and the methylation switch (+/-) in schizophrenia. 1657 35

Aberrant transcriptional regulation may be one of the key components of the pathophysiology of mood disorders. DNA methylation generally acts as an epigenetic gene silencing mechanism and is catalyzed by a group of enzymes known as DNA methyltransferases (DNMTs). Several lines of evidence have suggested aberrant DNA methylation in patients with neuropsychiatric disorders and in animal models for psychiatric disorders. However, the involvement of DNMTs in the pathophysiology of mood disorders is not completely understood. In this study, we aimed to determine whether there are alterations in the expression of DNMTs mRNA in mood disorder patients. We used quantitative real-time PCR to measure the mRNA expression of four DNMT isoforms in the peripheral white blood cells of major depressive disorder (MDD) and bipolar disorder (BPD) patients during a depressive and a remissive episode. We found that the levels of DNMT1 mRNA were significantly decreased in a depressive but not in a remissive state of MDD and BPD. In addition, the levels of DNMT3B mRNA in MDD were significantly increased in a depressive but not in a remissive state. Thus, our data suggest that the altered expression of DNMTs is state dependent and that the aberrant epigenetic gene regulations caused by the altered expression of DNMT1 and DNMT3B may be associated with the pathophysiology of mood disorders.
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PMID:State-dependent changes in the expression of DNA methyltransferases in mood disorder patients. 2159 22

Recent human and animal studies suggest that epigenetic mechanisms mediate the impact of environment on development of mental disorders. Therefore, we hypothesized that polymorphisms in epigenetic-regulatory genes impact stress-induced emotional changes. A multi-step, multi-sample gene-environment interaction analysis was conducted to test whether 31 single nucleotide polymorphisms (SNPs) in epigenetic-regulatory genes, i.e. three DNA methyltransferase genes DNMT1, DNMT3A, DNMT3B, and methylenetetrahydrofolate reductase (MTHFR), moderate emotional responses to stressful and pleasant stimuli in daily life as measured by Experience Sampling Methodology (ESM). In the first step, main and interactive effects were tested in a sample of 112 healthy individuals. Significant associations in this discovery sample were then investigated in a population-based sample of 434 individuals for replication. SNPs showing significant effects in both the discovery and replication samples were subsequently tested in three other samples of: (i) 85 unaffected siblings of patients with psychosis, (ii) 110 patients with psychotic disorders, and iii) 126 patients with a history of major depressive disorder. Multilevel linear regression analyses showed no significant association between SNPs and negative affect or positive affect. No SNPs moderated the effect of pleasant stimuli on positive affect. Three SNPs of DNMT3A (rs11683424, rs1465764, rs1465825) and 1 SNP of MTHFR (rs1801131) moderated the effect of stressful events on negative affect. Only rs11683424 of DNMT3A showed consistent directions of effect in the majority of the 5 samples. These data provide the first evidence that emotional responses to daily life stressors may be moderated by genetic variation in the genes involved in the epigenetic machinery.
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PMID:Epigenetic genes and emotional reactivity to daily life events: a multi-step gene-environment interaction study. 2496 10

Stress in early life has been appointed as an important phenomenon in the onset of depression and poor response to treatment with classical antidepressants. Furthermore, childhood trauma triggers epigenetic changes, which are associated with the pathophysiology of major depressive disorder (MDD). Treatment with atypical antipsychotics such as quetiapine, exerts therapeutic effect for MDD patients and induces epigenetic changes. This study aimed to analyze the effect of chronic treatment with quetiapine (20mg/kg) on depressive-like behavior of rats submitted to maternal deprivation (MD), as well as the activity of histone acetylation by the enzymes histone acetyl transferases (HAT) and deacetylases (HDAC) and DNA methylation, through DNA methyltransferase enzyme (DNMT) in the prefrontal cortex (PFC), nucleus accumbens (NAc) and hippocampus. Maternally deprived rats had a depressive-like behavior in the forced swimming test and an increase in the HDAC and DNMT activities in the hippocampus and NAc. Treatment with quetiapine reversed depressive-like behavior and reduced the DNMT activity in the hippocampus. This is the first study to show the antidepressant-like effect of quetiapine in animals subjected to MD and a protective effect by quetiapine in reducing epigenetic changes induced by stress in early life. These results reinforce an important role of quetiapine as therapy for MDD.
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PMID:Quetiapine treatment reverses depressive-like behavior and reduces DNA methyltransferase activity induced by maternal deprivation. 2791 54