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Urb M, Niinep K, Matsalu T, Kipper K, Herodes K, Zharkovsky A, Timmusk T, Anier K, Kalda A. The role of DNA methyltransferase activity in cocaine treatment and withdrawal in the nucleus accumbens of mice. Addict Biol 2020; 25:e12720. [PMID: 30730091 DOI: 10.1111/adb.12720] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/07/2018] [Accepted: 01/08/2019] [Indexed: 01/02/2023]
Abstract
An increasing number of reports have provided crucial evidence that epigenetic modifications, such as DNA methylation, may be involved in initiating and establishing psychostimulant-induced stable changes at the cellular level by coordinating the expression of gene networks, which then manifests as long-term behavioral changes. In this study, we evaluated the enzyme activity of DNA methyltransferases (DNMTs) after cocaine treatment and during withdrawal. Furthermore, we studied how genetic or pharmacological inhibition of DNMTs in mouse nucleus accumbens (NAc) affects the induction and expression of cocaine-induced behavioral sensitization. Our results showed that after silencing Dnmt3a in the NAc during the induction phase of cocaine-induced sensitization, overall DNMT activity decreases, correlating negatively with behavioral sensitization. Reduced Dnmt3a mRNA during this phase was the largest contributing factor for decreased DNMT activity. Cocaine withdrawal and a challenge dose increased DNMT activity in the NAc, which was associated with the expression of behavioral sensitization. Long-term selective Dnmt3a transcription silencing in the NAc did not alter DNMT activity or the expression of cocaine-induced behavioral sensitization. However, bilateral intra-NAc injection of a non-specific inhibitor of DNMT (RG108) during withdrawal from cocaine decreased DNMT activity in the NAc and had a small effect on the expression of cocaine-induced behavioral sensitization. Thus, cocaine treatment and withdrawal is associated with biphasic changes in DNMT activity in the NAc, and the expression of behavioral sensitization decreases with non-selective inhibition of DNMT but not with selective silencing of Dnmt3a.
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Affiliation(s)
- Mari Urb
- Department of PharmacologyInstitute of Biomedicine and Translational Medicine, University of Tartu Estonia
| | - Kerly Niinep
- Department of PharmacologyInstitute of Biomedicine and Translational Medicine, University of Tartu Estonia
| | - Terje Matsalu
- Department of PharmacologyInstitute of Biomedicine and Translational Medicine, University of Tartu Estonia
| | - Karin Kipper
- Institute of Chemistry, University of Tartu Estonia
| | - Koit Herodes
- Institute of Chemistry, University of Tartu Estonia
| | - Alexander Zharkovsky
- Department of PharmacologyInstitute of Biomedicine and Translational Medicine, University of Tartu Estonia
| | - Tõnis Timmusk
- Institute of Chemistry and Biotechnology, Tallinn University of Technology Estonia
| | - Kaili Anier
- Department of PharmacologyInstitute of Biomedicine and Translational Medicine, University of Tartu Estonia
| | - Anti Kalda
- Department of PharmacologyInstitute of Biomedicine and Translational Medicine, University of Tartu Estonia
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Urb M, Anier K, Matsalu T, Aonurm-Helm A, Tasa G, Koppel I, Zharkovsky A, Timmusk T, Kalda A. Glucocorticoid Receptor Stimulation Resulting from Early Life Stress Affects Expression of DNA Methyltransferases in Rat Prefrontal Cortex. J Mol Neurosci 2019; 68:99-110. [PMID: 30852742 DOI: 10.1007/s12031-019-01286-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 02/25/2019] [Indexed: 12/14/2022]
Abstract
Early life stress initiates long-term neurobiological changes that affect stress resilience and increased susceptibility to psychopathology. Maternal separation (MS) is used to cause early life stress and it induces profound neurochemical and behavioral changes that last until adulthood. The molecular pathways of how MS affects the regulation of DNA methyltransferases (Dnmt) in brain have not been entirely characterized. We evaluated MS effects on Dnmt1, Dnmt3a and Dnmt3b expression, DNMT enzyme activity and glucocorticoid receptor (GR) recruitment to different Dnmt loci in the prefrontal cortex (PFC) of Wistar rats. We found increased plasma corticosterone levels after MS that were associated with induced Dnmt expression and enzyme activity in rat PFC at post-natal day 15 (PND15). Chromatin immunoprecipitation showed increased binding of GR at the Dnmt3b promoter after MS, suggesting that genomic signaling of GR is an important regulatory mechanism for the induced Dnmt3b expression and DNMT activity. Although GR also binds to Dnmt3a promoter and a putative regulatory region in intron 3 in rat PFC, its expression after maternal separation may be influenced by other mechanisms. Therefore, GR could be a link between early life stress experience and long-term gene expression changes induced by aberrant DNA methylation.
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Affiliation(s)
- Mari Urb
- Department of Pharmacology, Institute of Biomedicine and Translational Medicine, University of Tartu, 19 Ravila Street, 50411, Tartu, Estonia
| | - Kaili Anier
- Department of Pharmacology, Institute of Biomedicine and Translational Medicine, University of Tartu, 19 Ravila Street, 50411, Tartu, Estonia
| | - Terje Matsalu
- Department of Pharmacology, Institute of Biomedicine and Translational Medicine, University of Tartu, 19 Ravila Street, 50411, Tartu, Estonia
| | - Anu Aonurm-Helm
- Department of Pharmacology, Institute of Biomedicine and Translational Medicine, University of Tartu, 19 Ravila Street, 50411, Tartu, Estonia
| | - Gunnar Tasa
- Department of Human Biology and Genetics, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Indrek Koppel
- Institute of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia.,Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Alexander Zharkovsky
- Department of Pharmacology, Institute of Biomedicine and Translational Medicine, University of Tartu, 19 Ravila Street, 50411, Tartu, Estonia
| | - Tõnis Timmusk
- Institute of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Anti Kalda
- Department of Pharmacology, Institute of Biomedicine and Translational Medicine, University of Tartu, 19 Ravila Street, 50411, Tartu, Estonia.
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Urb M, Anier K, Matsalu T, Aonurm-Helm A, Timmusk T. Corticosterone induces DNA methyltransferases expression in rat cortical neurons. SpringerPlus 2015. [PMCID: PMC4796310 DOI: 10.1186/2193-1801-4-s1-p50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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