1
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Flynn LT, Gao WJ. DNA methylation and the opposing NMDAR dysfunction in schizophrenia and major depression disorders: a converging model for the therapeutic effects of psychedelic compounds in the treatment of psychiatric illness. Mol Psychiatry 2023; 28:4553-4567. [PMID: 37679470 PMCID: PMC11034997 DOI: 10.1038/s41380-023-02235-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 08/17/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023]
Abstract
Psychedelic compounds are being increasingly explored as a potential therapeutic option for treating several psychiatric conditions, despite relatively little being known about their mechanism of action. One such possible mechanism, DNA methylation, is a process of epigenetic regulation that changes gene expression via chemical modification of nitrogenous bases. DNA methylation has been implicated in the pathophysiology of several psychiatric conditions, including schizophrenia (SZ) and major depressive disorder (MDD). In this review, we propose alterations to DNA methylation as a converging model for the therapeutic effects of psychedelic compounds, highlighting the N-methyl D-aspartate receptor (NMDAR), a crucial mediator of synaptic plasticity with known dysfunction in both diseases, as an example and anchoring point. We review the established evidence relating aberrant DNA methylation to NMDAR dysfunction in SZ and MDD and provide a model asserting that psychedelic substances may act through an epigenetic mechanism to provide therapeutic effects in the context of these disorders.
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Affiliation(s)
- L Taylor Flynn
- Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
- MD/PhD program, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Wen-Jun Gao
- Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA.
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2
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Global DNA methylation changes in adults with attention deficit-hyperactivity disorder and its comorbidity with bipolar disorder: links with polygenic scores. Mol Psychiatry 2022; 27:2485-2491. [PMID: 35256746 DOI: 10.1038/s41380-022-01493-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/05/2022] [Accepted: 02/14/2022] [Indexed: 11/09/2022]
Abstract
Genetic and environmental factors contribute to the etiology of Attention Deficit-Hyperactivity Disorder (ADHD). In this sense, the study of epigenetic mechanisms could contribute to the understanding of the disorder's neurobiology. Global DNA methylation (GMe) evaluated through 5-methylcytosine levels could be a promising epigenetic biomarker to capture long-lasting biological effects in response to environmental and hormonal changes. We conducted the first assessment of GMe levels in subjects with ADHD (n = 394) and its main comorbidities in comparison to populational controls (n = 390). Furthermore, given the high genetic contribution to ADHD (heritability of 80%), polygenic risk scores (PRS) were calculated to verify the genetic contribution to GMe levels in ADHD and the comorbidities associated with GMe levels. The GMe levels observed in patients were lower than controls (P = 1.1e-8), with women being significantly less globally methylated than men (P = 0.002). Regarding comorbidities, the presence of bipolar disorder (BD) among patients with ADHD was associated with higher methylation levels compared to patients with ADHD without BD (P = 0.031). The results did not change when pharmacological treatment was accounted for in the analyses. The ADHD and BD most predictive PRSs were negatively (P = 0.0064) and positively (P = 0.0042) correlated with GMe, respectively. This study is the first to report an association between GMe, ADHD, and its comorbidity with BD and associations between PRSs for specific psychiatric disorders and GMe. Our findings add to previous evidence that GMe may be a relevant piece in the psychiatric disorders' etiological landscape.
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3
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Francisco RD, Fernando V, Norma E, Madai ME, Marcelo B. Glial changes in schizophrenia: Genetic and epigenetic approach. Indian J Psychiatry 2022; 64:3-12. [PMID: 35400734 PMCID: PMC8992743 DOI: 10.4103/indianjpsychiatry.indianjpsychiatry_104_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 10/24/2021] [Accepted: 12/23/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Schizophrenia (SCZ) is a severe mental illness that affects one percent of the population, affecting how people think, feel, and behave. Evidence suggests glial cell alteration and some researchers have found genetic risk loci and epigenetic marks that may regulate glia-related genes implicated in SCZ. AIM The aim of this study is to identify genetic and epigenetic changes that have been reported in glial cells or glial-associated genes in SCZ. MATERIALS AND METHODS We searched the articles from PubMed, PubMed Central, Medline, Medscape, and Embase databases up to December 2020 to identify relevant peer-reviewed articles in English. The titles and abstracts were screened to eliminate irrelevant citations. RESULTS Twenty-four original articles were included in the review. Studies were categorized into the following four thematic via: (1) oligodendrocytes, (2) microglia, (3) astrocytes, and (4) perspectives. CONCLUSION This study is the first of its kind to review research on genetic variants and epigenetic modifications associated with glia-related genes implicated in SCZ. Epigenetic evidence is considerably less than genetic evidence in this field. Understanding the pathways of some risk genes and their genetic and epigenetic regulation allows us to understand and find potential targets for future interventions in this mental illness.
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Affiliation(s)
- Ramos Daniel Francisco
- Faculty of Chemical Sciences, Juarez University of the State of Durango, Durango, Mexico
| | - Vazquez Fernando
- Faculty of Chemical Sciences, Juarez University of the State of Durango, Durango, Mexico.,Research Unit, General Hospital 450, Durango, Mexico
| | - Estrada Norma
- Faculty of Chemical Sciences, Juarez University of the State of Durango, Durango, Mexico
| | - Méndez Edna Madai
- Scientific Research Institute, Juarez University of the State of Durango, Durango, Mexico
| | - Barraza Marcelo
- Faculty of Chemical Sciences, Juarez University of the State of Durango, Durango, Mexico
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4
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Srivastava A, Dada O, Qian J, Al-Chalabi N, Fatemi AB, Gerretsen P, Graff A, De Luca V. Epigenetics of Schizophrenia. Psychiatry Res 2021; 305:114218. [PMID: 34638051 DOI: 10.1016/j.psychres.2021.114218] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/07/2021] [Accepted: 09/20/2021] [Indexed: 12/31/2022]
Abstract
Schizophrenia (SCZ) is a chronic psychotic disorder that contributes significantly to disability, affecting behavior, thought, and cognition. It has long been known that there is a heritable component to schizophrenia; studies in both the pre-genomic and post-genomic era, however, have failed to elucidate fully the genetic basis for this complex disease. Epigenetic processes - broadly, those which contribute to changes in gene expression without altering the genetic code itself - may help to understand better the mechanisms leading to development of SCZ. The objective of this review is to synthesize current knowledge of the epigenetic mechanisms involved in schizophrenia. Specifically, DNA methylation studies in both peripheral and post-mortem brain samples in SCZ are reviewed, as are epigenetic mechanisms including histone modification. The promising role of non-coding RNA including micro-RNA (miRNA) and its role as a potential diagnostic and therapeutic biomarker is outlined, as are epigenetic age acceleration and telomere shortening. Finally, we discuss limitations in current knowledge and propose future research directions.
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Affiliation(s)
| | | | | | | | | | | | - Ariel Graff
- Department of Psychiatry, University of Toronto
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5
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Magwai T, Shangase KB, Oginga FO, Chiliza B, Mpofana T, Xulu KR. DNA Methylation and Schizophrenia: Current Literature and Future Perspective. Cells 2021; 10:2890. [PMID: 34831111 PMCID: PMC8616184 DOI: 10.3390/cells10112890] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/09/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Schizophrenia is a neuropsychiatric disorder characterized by dissociation of thoughts, idea, identity, and emotions. It has no central pathophysiological mechanism and precise diagnostic markers. Despite its high heritability, there are also environmental factors implicated in the development of schizophrenia. Epigenetic factors are thought to mediate the effects of environmental factors in the development of the disorder. Epigenetic modifications like DNA methylation are a risk factor for schizophrenia. Targeted gene approach studies attempted to find candidate gene methylation, but the results are contradictory. Genome-wide methylation studies are insufficient in literature and the available data do not cover different populations like the African populations. The current genome-wide studies have limitations related to the sample and methods used. Studies are required to control for these limitations. Integration of DNA methylation, gene expression, and their effects are important in the understanding of the development of schizophrenia and search for biomarkers. There are currently no precise and functional biomarkers for the disorder. Several epigenetic markers have been reported to be common in functional and peripheral tissue. This makes the peripheral tissue epigenetic changes a surrogate of functional tissue, suggesting common epigenetic alteration can be used as biomarkers of schizophrenia in peripheral tissue.
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Affiliation(s)
- Thabo Magwai
- Department of Physiology, School of Laboratory Medicine and Medical Sciences, University of Kwa-Zulu Natal, Durban 4001, South Africa; (K.B.S.); (F.O.O.); (T.M.)
- National Health Laboratory Service, Department of Chemical Pathology, University of Kwa-Zulu Natal, Durban 4085, South Africa
| | - Khanyiso Bright Shangase
- Department of Physiology, School of Laboratory Medicine and Medical Sciences, University of Kwa-Zulu Natal, Durban 4001, South Africa; (K.B.S.); (F.O.O.); (T.M.)
| | - Fredrick Otieno Oginga
- Department of Physiology, School of Laboratory Medicine and Medical Sciences, University of Kwa-Zulu Natal, Durban 4001, South Africa; (K.B.S.); (F.O.O.); (T.M.)
| | - Bonginkosi Chiliza
- Department of Psychiatry, Nelson R Mandela School of Medicine, University of Kwa-Zulu Natal, Durban 4001, South Africa;
| | - Thabisile Mpofana
- Department of Physiology, School of Laboratory Medicine and Medical Sciences, University of Kwa-Zulu Natal, Durban 4001, South Africa; (K.B.S.); (F.O.O.); (T.M.)
| | - Khethelo Richman Xulu
- Department of Physiology, School of Laboratory Medicine and Medical Sciences, University of Kwa-Zulu Natal, Durban 4001, South Africa; (K.B.S.); (F.O.O.); (T.M.)
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6
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Fernandes SB, Grova N, Roth S, Duca RC, Godderis L, Guebels P, Mériaux SB, Lumley AI, Bouillaud-Kremarik P, Ernens I, Devaux Y, Schroeder H, Turner JD. N 6-Methyladenine in Eukaryotic DNA: Tissue Distribution, Early Embryo Development, and Neuronal Toxicity. Front Genet 2021; 12:657171. [PMID: 34108991 PMCID: PMC8181416 DOI: 10.3389/fgene.2021.657171] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/12/2021] [Indexed: 01/09/2023] Open
Abstract
DNA methylation is one of the most important epigenetic modifications and is closely related with several biological processes such as regulation of gene transcription and the development of non-malignant diseases. The prevailing dogma states that DNA methylation in eukaryotes occurs essentially through 5-methylcytosine (5mC) but recently adenine methylation was also found to be present in eukaryotes. In mouse embryonic stem cells, 6-methyladenine (6mA) was associated with the repression and silencing of genes, particularly in the X-chromosome, known to play an important role in cell fate determination. Here, we have demonstrated that 6mA is a ubiquitous eukaryotic epigenetic modification that is put in place during epigenetically sensitive periods such as embryogenesis and fetal development. In somatic cells there are clear tissue specificity in 6mA levels, with the highest 6mA levels being observed in the brain. In zebrafish, during the first 120 h of embryo development, from a single pluripotent cell to an almost fully formed individual, 6mA levels steadily increase. An identical pattern was observed over embryonic days 7–21 in the mouse. Furthermore, exposure to a neurotoxic environmental pollutant during the same early life period may led to a decrease in the levels of this modification in female rats. The identification of the periods during which 6mA epigenetic marks are put in place increases our understanding of this mammalian epigenetic modification, and raises the possibility that it may be associated with developmental processes.
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Affiliation(s)
- Sara B Fernandes
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg.,Faculty of Science, Technology and Medicine, University of Luxembourg, Belval, Luxembourg
| | - Nathalie Grova
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg.,Calbinotox, EA7488, Faculty of Science and Technology, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Sarah Roth
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Radu Corneliu Duca
- Unit Environmental Hygiene and Human Biological Monitoring, Department of Health Protection, National Health Laboratory (LNS), Dudelange, Luxembourg.,Centre for Environment and Health, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium
| | - Lode Godderis
- Centre for Environment and Health, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium.,IDEWE, External Service for Prevention and Protection at Work, Heverlee, Belgium
| | - Pauline Guebels
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Sophie B Mériaux
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Andrew I Lumley
- Cardiovascular Research Unit, Department of Public Health, Luxembourg Institute of Health, Strassen, Luxembourg
| | | | - Isabelle Ernens
- Cardiovascular Research Unit, Department of Public Health, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Yvan Devaux
- Cardiovascular Research Unit, Department of Public Health, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Henri Schroeder
- Calbinotox, EA7488, Faculty of Science and Technology, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Jonathan D Turner
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
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7
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Imamura A, Morimoto Y, Ono S, Kurotaki N, Kanegae S, Yamamoto N, Kinoshita H, Tsujita T, Okazaki Y, Ozawa H. Genetic and environmental factors of schizophrenia and autism spectrum disorder: insights from twin studies. J Neural Transm (Vienna) 2020; 127:1501-1515. [PMID: 32285255 PMCID: PMC7578126 DOI: 10.1007/s00702-020-02188-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/05/2020] [Indexed: 02/06/2023]
Abstract
Twin studies of psychiatric disorders such as schizophrenia and autism spectrum disorder have employed epidemiological approaches that determine heritability by comparing the concordance rate between monozygotic twins (MZs) and dizygotic twins. The basis for these studies is that MZs share 100% of their genetic information. Recently, biological studies based on molecular methods are now being increasingly applied to examine the differences between MZs discordance for psychiatric disorders to unravel their possible causes. Although recent advances in next-generation sequencing have increased the accuracy of this line of research, there has been greater emphasis placed on epigenetic changes versus DNA sequence changes as the probable cause of discordant psychiatric disorders in MZs. Since the epigenetic status differs in each tissue type, in addition to the DNA from the peripheral blood, studies using DNA from nerve cells induced from postmortem brains or induced pluripotent stem cells are being carried out. Although it was originally thought that epigenetic changes occurred as a result of environmental factors, and thus were not transmittable, it is now known that such changes might possibly be transmitted between generations. Therefore, the potential possible effects of intestinal flora inside the body are currently being investigated as a cause of discordance in MZs. As a result, twin studies of psychiatric disorders are greatly contributing to the elucidation of genetic and environmental factors in the etiology of psychiatric conditions.
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Affiliation(s)
- Akira Imamura
- Child and Adolescent Psychiatry Community Partnership Unit, Nagasaki University Hospital, Nagasaki, Japan.
| | - Yoshiro Morimoto
- Unit of Translation Medicine, Department of Neuropsychiatry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Department of Human Genetics, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Shinji Ono
- Department of Human Genetics, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Naohiro Kurotaki
- Department of Clinical Psychiatry, Graduate School of Medicine, Kagawa University, Kita-gun, Japan
| | - Shinji Kanegae
- Child and Adolescent Psychiatry Community Partnership Unit, Nagasaki University Hospital, Nagasaki, Japan
| | - Naoki Yamamoto
- Child and Adolescent Psychiatry Community Partnership Unit, Nagasaki University Hospital, Nagasaki, Japan
- Unit of Translation Medicine, Department of Neuropsychiatry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Hirohisa Kinoshita
- Unit of Translation Medicine, Department of Neuropsychiatry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | | | - Yuji Okazaki
- Koseikai Michinoo Hospital, Nagasaki, Japan
- Tokyo Metropolitan Matsuzawa Hospital, Tokyo, Japan
| | - Hiroki Ozawa
- Child and Adolescent Psychiatry Community Partnership Unit, Nagasaki University Hospital, Nagasaki, Japan
- Unit of Translation Medicine, Department of Neuropsychiatry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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8
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Epigenomic Dysregulation in Schizophrenia: In Search of Disease Etiology and Biomarkers. Cells 2020; 9:cells9081837. [PMID: 32764320 PMCID: PMC7463953 DOI: 10.3390/cells9081837] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/27/2020] [Accepted: 07/31/2020] [Indexed: 12/13/2022] Open
Abstract
Schizophrenia is a severe psychiatric disorder with a complex array of signs and symptoms that causes very significant disability in young people. While schizophrenia has a strong genetic component, with heritability around 80%, there is also a very significant range of environmental exposures and stressors that have been implicated in disease development and neuropathology, such as maternal immune infection, obstetric complications, childhood trauma and cannabis exposure. It is postulated that epigenetic factors, as well as regulatory non-coding RNAs, mediate the effects of these environmental stressors. In this review, we explore the most well-known epigenetic marks, including DNA methylation and histone modification, along with emerging RNA mediators of epigenomic state, including miRNAs and lncRNAs, and discuss their collective potential for involvement in the pathophysiology of schizophrenia implicated through the postmortem analysis of brain tissue. Given that peripheral tissues, such as blood, saliva, and olfactory epithelium have the same genetic composition and are exposed to many of the same environmental exposures, we also examine some studies supporting the application of peripheral tissues for epigenomic biomarker discovery in schizophrenia. Finally, we provide some perspective on how these biomarkers may be utilized to capture a signature of past events that informs future treatment.
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9
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Burghardt KJ, Khoury AS, Msallaty Z, Yi Z, Seyoum B. Antipsychotic Medications and DNA Methylation in Schizophrenia and Bipolar Disorder: A Systematic Review. Pharmacotherapy 2020; 40:331-342. [PMID: 32058614 DOI: 10.1002/phar.2375] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The pharmacoepigenetics of antipsychotic treatment in severe mental illness is a growing area of research that aims to understand the interface between antipsychotic treatment and genetic regulation. Pharmacoepigenetics may some day assist in identifying treatment response mechanisms or become one of the components in the implementation of precision medicine. To understand the current evidence regarding the effects of antipsychotics on DNA methylation a systematic review with qualitative synthesis was performed through Pubmed, Embase and Psychinfo from earliest data to June 2019. Studies were included if they analyzed DNA methylation in an antipsychotic-treated population of patients with schizophrenia or bipolar disorder. Data extraction occurred via a standardized format and study quality was assessed. Twenty-nine studies were identified for inclusion. Study design, antipsychotic type, sample source, and methods of DNA methylation measurement varied across all studies. Eighteen studies analyzed methylation in patients with schizophrenia, four studies in patients with bipolar disorder, and seven studies in a combined sample of schizophrenia and bipolar disorder. Twenty-two studies used observational samples whereas the remainder used prospectively treated samples. Six studies assessed global methylation, five assessed epigenome-wide, and 15 performed a candidate epigenetic study. Two studies analyzed both global and gene-specific methylation, whereas one study performed a simultaneous epigenome-wide and gene-specific study. Only three genes were analyzed in more than one gene-specific study and the findings were discordant. The state of the pharmacoepigenetic literature on antipsychotic use is still in its early stages and uniform reporting of methylation site information is needed. Future work should concentrate on using prospective sampling with appropriate control groups and begin to replicate many of the novel associations that have been reported.
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Affiliation(s)
- Kyle J Burghardt
- Wayne State University Eugene Applebaum College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Audrey S Khoury
- Wayne State University Eugene Applebaum College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Zaher Msallaty
- Wayne State University Eugene Applebaum College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Zhengping Yi
- Wayne State University Eugene Applebaum College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Berhane Seyoum
- Wayne State University School of Medicine, Detroit, Michigan
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10
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Twin studies of brain structure and cognition in schizophrenia. Neurosci Biobehav Rev 2019; 109:103-113. [PMID: 31843545 DOI: 10.1016/j.neubiorev.2019.12.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 11/20/2022]
Abstract
Twin studies in schizophrenia have been crucial in establishing estimates for the heritability and thus providing evidence for a genetic component in this disorder. Recent years have seen the application of the twin study paradigm to both putative intermediate phenotypes and biomarkers of disease as well as a diversification of its use in schizophrenia research. This review addressed studies of brain structure (T1 morphometry) and cognition in schizophrenia using twin study designs. We review major findings such as the overlap of genetic variance between schizophrenia and cognition as a model for the emergence of psychopathology. The use of novel hybrid models integrating molecular genetic risk markers, as well as the use of twin studies in epigenetics might prove to significantly enhance schizophrenia research in the post-GWAS era.
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11
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Alfimova MV, Kondratiev NV, Golov AK, Golimbet VE. Methylation of the Reelin Gene Promoter in Peripheral Blood and Its Relationship with the Cognitive Function of Schizophrenia Patients. Mol Biol 2018. [DOI: 10.1134/s0026893318050023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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12
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Liu C, Jiao C, Wang K, Yuan N. DNA Methylation and Psychiatric Disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 157:175-232. [PMID: 29933950 DOI: 10.1016/bs.pmbts.2018.01.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
DNA methylation has been an important area of research in the study of molecular mechanism to psychiatric disorders. Recent evidence has suggested that abnormalities in global methylation, methylation of genes, and pathways could play a role in the etiology of many forms of mental illness. In this article, we review the mechanisms of DNA methylation, including the genetic and environmental factors affecting methylation changes. We report and discuss major findings regarding DNA methylation in psychiatric patients, both within the context of global methylation studies and gene-specific methylation studies. Finally, we discuss issues surrounding data quality improvement, the limitations of current methylation analysis methods, and the possibility of using DNA methylation-based treatment for psychiatric disorders in the future.
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Affiliation(s)
- Chunyu Liu
- University of Illinois, Chicago, IL, United States; School of Life Science, Central South University, Changsha, China.
| | - Chuan Jiao
- School of Life Science, Central South University, Changsha, China
| | - Kangli Wang
- School of Life Science, Central South University, Changsha, China
| | - Ning Yuan
- Hunan Brain Hospital, Changsha, China
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13
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Ovenden ES, McGregor NW, Emsley RA, Warnich L. DNA methylation and antipsychotic treatment mechanisms in schizophrenia: Progress and future directions. Prog Neuropsychopharmacol Biol Psychiatry 2018; 81:38-49. [PMID: 29017764 DOI: 10.1016/j.pnpbp.2017.10.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/01/2017] [Accepted: 10/04/2017] [Indexed: 12/15/2022]
Abstract
Antipsychotic response in schizophrenia is a complex, multifactorial trait influenced by pharmacogenetic factors. With genetic studies thus far providing little biological insight or clinical utility, the field of pharmacoepigenomics has emerged to tackle the so-called "missing heritability" of drug response in disease. Research on psychiatric disorders has only recently started to assess the link between epigenetic alterations and treatment outcomes. DNA methylation, the best characterised epigenetic mechanism to date, is discussed here in the context of schizophrenia and antipsychotic treatment outcomes. The majority of published studies have assessed the influence of antipsychotics on methylation levels in specific neurotransmitter-associated candidate genes or at the genome-wide level. While these studies illustrate the epigenetic modifications associated with antipsychotics, very few have assessed clinical outcomes and the potential of differential DNA methylation profiles as predictors of antipsychotic response. Results from other psychiatric disorder studies, such as depression and bipolar disorder, provide insight into what may be achieved by schizophrenia pharmacoepigenomics. Other aspects that should be addressed in future research include methodological challenges, such as tissue specificity, and the influence of genetic variation on differential methylation patterns.
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Affiliation(s)
- Ellen S Ovenden
- Department of Genetics, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Nathaniel W McGregor
- Department of Genetics, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Robin A Emsley
- Department of Psychiatry, Stellenbosch University, Tygerberg 7505, South Africa
| | - Louise Warnich
- Department of Genetics, Stellenbosch University, Stellenbosch 7600, South Africa.
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14
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Abstract
Schizophrenia is a highly heritable psychiatric condition that displays a complex phenotype. A multitude of genetic susceptibility loci have now been identified, but these fail to explain the high heritability estimates of schizophrenia. In addition, epidemiologically relevant environmental risk factors for schizophrenia may lead to permanent changes in brain function. In conjunction with genetic liability, these environmental risk factors-likely through epigenetic mechanisms-may give rise to schizophrenia, a clinical syndrome characterized by florid psychotic symptoms and moderate to severe cognitive impairment. These pathophysiological features point to the involvement of epigenetic processes. Recently, a wave of studies examining aberrant DNA modifications in schizophrenia was published. This chapter aims to comprehensively review the current findings, from both candidate gene studies and genome-wide approaches, on DNA methylation changes in schizophrenia.
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15
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Alfimova MV, Kondratiev NV, Golimbet VE. Results and promises of genetics of cognitive impairment in schizophrenia: epigenetic approaches. Zh Nevrol Psikhiatr Im S S Korsakova 2017. [DOI: 10.17116/jnevro201711721130-135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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16
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Fisher PA, Beauchamp KG, Roos LE, Noll LK, Flannery J, Delker BC. The Neurobiology of Intervention and Prevention in Early Adversity. Annu Rev Clin Psychol 2016; 12:331-57. [DOI: 10.1146/annurev-clinpsy-032814-112855] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Philip A. Fisher
- Department of Psychology, University of Oregon, Eugene, Oregon 97403;
| | - Kate G. Beauchamp
- Department of Psychology, University of Oregon, Eugene, Oregon 97403;
| | - Leslie E. Roos
- Department of Psychology, University of Oregon, Eugene, Oregon 97403;
| | - Laura K. Noll
- Department of Psychology, University of Oregon, Eugene, Oregon 97403;
| | - Jessica Flannery
- Department of Psychology, University of Oregon, Eugene, Oregon 97403;
| | - Brianna C. Delker
- Department of Psychology, University of Oregon, Eugene, Oregon 97403;
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Teroganova N, Girshkin L, Suter CM, Green MJ. DNA methylation in peripheral tissue of schizophrenia and bipolar disorder: a systematic review. BMC Genet 2016; 17:27. [PMID: 26809779 PMCID: PMC4727379 DOI: 10.1186/s12863-016-0332-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/13/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Increasing evidence suggests the involvement of epigenetic processes in the development of schizophrenia and bipolar disorder, and recent reviews have focused on findings in post-mortem brain tissue. A systematic review was conducted to synthesise and evaluate the quality of available evidence for epigenetic modifications (specifically DNA methylation) in peripheral blood and saliva samples of schizophrenia and bipolar disorder patients in comparison to healthy controls. METHODS Original research articles using humans were identified using electronic databases. There were 33 included studies for which data were extracted and graded in duplicate on 22 items of the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement, to assess methodological precision and quality of reporting. RESULTS There were 15 genome-wide and 18 exclusive candidate gene loci investigations for DNA methylation studies. A number of common genes were identified as differentially methylated in schizophrenia/bipolar disorder, which were related to reelin, brain-derived neurotrophic factor, dopamine (including the catechol-O-methyltransferase gene), serotonin and glutamate, despite inconsistent findings of hyper-, hypo-, or lack of methylation at these and other loci. The mean STROBE score of 59% suggested moderate quality of available evidence; however, wide methodological variability contributed to a lack of consistency in the way methylation levels were quantified, such that meta-analysis of the results was not possible. CONCLUSIONS Moderate quality of available evidence shows some convergence of differential methylation at some common genetic loci in schizophrenia and bipolar disorder, despite wide variation in methodology and reporting across studies. Improvement in the clarity of reporting clinical and other potential confounds would be useful in future studies of epigenetic processes in the context of exposure to environmental and other risk factors.
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Affiliation(s)
- Nina Teroganova
- School of Psychiatry, University of New South Wales, Randwick, NSW, Australia.
- Schizophrenia Research Institute, 405 Liverpool St, Darlinghurst, NSW, 2010, Australia.
| | - Leah Girshkin
- School of Psychiatry, University of New South Wales, Randwick, NSW, Australia.
- Schizophrenia Research Institute, 405 Liverpool St, Darlinghurst, NSW, 2010, Australia.
| | - Catherine M Suter
- Molecular Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia.
| | - Melissa J Green
- School of Psychiatry, University of New South Wales, Randwick, NSW, Australia.
- Schizophrenia Research Institute, 405 Liverpool St, Darlinghurst, NSW, 2010, Australia.
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.
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Misiak B, Szmida E, Karpiński P, Loska O, Sąsiadek MM, Frydecka D. Lower LINE-1 methylation in first-episode schizophrenia patients with the history of childhood trauma. Epigenomics 2015. [DOI: 10.2217/epi.15.68] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aim: We investigated methylation of DNA repetitive sequences (LINE-1 and BAGE) in peripheral blood leukocytes from first-episode schizophrenia (FES) patients and healthy controls (HCs) with respect to childhood adversities. Materials & methods: Patients were divided into two subgroups based on the history of childhood trauma – FES(+) and FES(-) subjects. The majority of HCs had a negative history of childhood trauma – HCs(-) subjects. Results: FES(+) patients had significantly lower LINE-1 methylation in comparison with FES(-) patients or HC(-) subjects. Emotional abuse and total trauma score predicted lower LINE-1 methylation in FES patients, while general trauma score was associated with lower BAGE methylation in HCs. Conclusion: Childhood adversities might be associated with global DNA hypomethylation in adult FES patients.
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Affiliation(s)
- Błażej Misiak
- Department of Psychiatry, Wroclaw Medical University, 10 Pasteur Street, 50-367 Wroclaw, Poland
- Department of Genetics, Wroclaw Medical University, 1 Marcinkowski Street, 50-368 Wroclaw, Poland
| | - Elżbieta Szmida
- Department of Genetics, Wroclaw Medical University, 1 Marcinkowski Street, 50-368 Wroclaw, Poland
| | - Paweł Karpiński
- Department of Genetics, Wroclaw Medical University, 1 Marcinkowski Street, 50-368 Wroclaw, Poland
| | - Olga Loska
- Department of Professional Training in Clinical Chemistry, Wroclaw Medical University, 211A Borowska Street, 50-566 Wroclaw, Poland
| | - Maria M Sąsiadek
- Department of Genetics, Wroclaw Medical University, 1 Marcinkowski Street, 50-368 Wroclaw, Poland
| | - Dorota Frydecka
- Department of Psychiatry, Wroclaw Medical University, 10 Pasteur Street, 50-367 Wroclaw, Poland
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da Silva VAM, Dantas MDS, Silva LADC, Carneiro JG, Schamber-Reis BLF. Testosterone Depletion Induces Demethylation of Murine Reelin Promoter CpG Dinucleotides: A Preliminary Study. BIOMED RESEARCH INTERNATIONAL 2015; 2015:286369. [PMID: 26526966 PMCID: PMC4615860 DOI: 10.1155/2015/286369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/10/2015] [Indexed: 01/17/2023]
Abstract
Schizophrenia (SZ) is a debilitating mental disorder characterized by psychotic events, abnormal social behavior, false beliefs, and auditory hallucinations. Hypermethylation of the promoter region of reelin (RELN), a gene involved in regulation of neuronal positioning during telencephalic development, is strongly associated with low protein expression in several cortical structures and promoter hypermethylation in brain from postmortem SZ subjects. Recent experimental data suggests that testosterone is able to promote RELN demethylation, although no direct evidence of hormonal influence on reelin promoter methylation was obtained. We investigated if reduced levels of plasma testosterone in adult male mice lead to Reln promoter demethylation. Animals were administered with flutamide, an antiandrogenic compound, and reelin promoter methylation was assessed using methylationspecific PCR using bisulfite DNA from cerebellum. We found that flutamide was able to significantly lower plasma testosterone when compared to control mice, and treatment did not influence animal survival and body weight. We also show that low plasma testosterone was associated with demethylation of a cytosine residue located at -860 in reelin promoter region. These preliminary data suggest that androgenic hormones can influence cerebral reelin demethylation. To our knowledge, this is the first experimental approach directly linking testosterone depletion and RELN promoter methylation.
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Affiliation(s)
- Victor Augusto Moraes da Silva
- Department of Medical Genetics, School of Medical Sciences, CESED/FCM, Avenida Senador Argemiro De Figueiredo 1901, Itararé, 58411-020 Campina Grande, PB, Brazil
| | - Marília de Souza Dantas
- Department of Medical Genetics, School of Medical Sciences, CESED/FCM, Avenida Senador Argemiro De Figueiredo 1901, Itararé, 58411-020 Campina Grande, PB, Brazil
| | - Leonardo Agostinho de Castro Silva
- Department of Medical Genetics, School of Medical Sciences, CESED/FCM, Avenida Senador Argemiro De Figueiredo 1901, Itararé, 58411-020 Campina Grande, PB, Brazil
| | - Juliana Garcia Carneiro
- Department of Medical Genetics, School of Medical Sciences, CESED/FCM, Avenida Senador Argemiro De Figueiredo 1901, Itararé, 58411-020 Campina Grande, PB, Brazil
| | - Bruno Luiz Fonseca Schamber-Reis
- Department of Medical Genetics, School of Medical Sciences, CESED/FCM, Avenida Senador Argemiro De Figueiredo 1901, Itararé, 58411-020 Campina Grande, PB, Brazil
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Castellani CA, Melka MG, Diehl EJ, Laufer BI, O'Reilly RL, Singh SM. DNA methylation in psychosis: insights into etiology and treatment. Epigenomics 2015; 7:67-74. [PMID: 25687467 DOI: 10.2217/epi.14.66] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Evidence for involvement of DNA methylation in psychosis forms the focus of this perspective. Of interest are results from two independent sets of experiments including rats treated with antipsychotic drugs and monozygotic twins discordant for schizophrenia. The results show that DNA methylation is increased in rats treated with antipsychotic drugs, reflecting the global effect of the drugs. Some of these changes are also seen in affected schizophrenic twins that were treated with antipsychotics. The genes and pathways identified in the unrelated experiments are relevant to neurodevelopment and psychiatric disorders. The common cause is hypothesized to be aberrations resulting from medication use. However, this needs to be established by future studies that address the origin of methylation changes in psychosis.
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Melka MG, Castellani CA, O'Reilly R, Singh SM. Insights into the origin of DNA methylation differences between monozygotic twins discordant for schizophrenia. J Mol Psychiatry 2015; 3:7. [PMID: 26137221 PMCID: PMC4487197 DOI: 10.1186/s40303-015-0013-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 06/15/2015] [Indexed: 12/22/2022] Open
Abstract
Background DNA methylation differences between monozygotic twins discordant for schizophrenia have been previously reported. However, the origin of methylation differences between monozygotic twins discordant for schizophrenia is not clear. The findings here argue that all DNA methylation differences may not necessarily represent the cause of the disease; rather some may result from the effect of antipsychotics. Methods Methylation differences in rat brain regions and also in two pairs of unrelated monozygotic twins discordant for schizophrenia have been studied using genome-wide DNA methylation arrays at Arraystar Inc. (Rockville, Maryland, USA). The identified gene promoters showing significant alterations to DNA methylation were then further characterized using ingenuity pathway analysis (Ingenuity System Inc, CA, USA). Results Pathway analysis of the most significant gene promoter hyper/hypomethylation revealed a significant enrichment of DNA methylation changes in biological networks and pathways directly relevant to neural development and psychiatric disorders. These included HIPPO signaling (p = 3.93E-03) and MAPK signaling (p = 4.27E-03) pathways involving hypermethylated genes in schizophrenia-affected patients as compared to their unaffected co-twins. Also, a number of significant pathways and networks involving genes with hypomethylated gene promoters have been identified. These included CREB signaling in neurons (p = 1.53E-02), Dopamine-DARPP32 feedback in cAMP signaling (p = 7.43E-03) and Ephrin receptors (p = 1.13E-02). Further, there was significant enrichment for pathways involved in nervous system development and function (p = 1.71E-03-4.28E-02). Conclusion The findings highlight the significance of antipsychotic drugs on DNA methylation in schizophrenia patients. The unique pathways affected by DNA methylation in the two pairs of monozygotic twins suggest that patient-specific pathways are responsible for the disease; suggesting that patient-specific treatment strategies may be necessary in treating the disorder. The study reflects the need for developing personalized medicine approaches that take into consideration epigenetic variations between patients. Electronic supplementary material The online version of this article (doi:10.1186/s40303-015-0013-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Melkaye G Melka
- Molecular Genetics Unit, Western Science Centre, Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7 Canada
| | - Christina A Castellani
- Molecular Genetics Unit, Western Science Centre, Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7 Canada
| | - Richard O'Reilly
- Department of Psychiatry, The University of Western Ontario, London, Ontario N6A 5B7 Canada
| | - Shiva M Singh
- Molecular Genetics Unit, Western Science Centre, Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7 Canada
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Guidotti A, Grayson DR. DNA methylation and demethylation as targets for antipsychotic therapy. DIALOGUES IN CLINICAL NEUROSCIENCE 2015. [PMID: 25364290 PMCID: PMC4214182 DOI: 10.31887/dcns.2014.16.3/aguidotti] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Schizophrenia (SZ) and bipolar disorder (BPD) patients show a downregulation of GAD67, reelin (RELN), brain-derived neurotrophic factor (BDNF), and other genes expressed in telencephalic GABAergic and glutamatergic neurons. This downregulation is associated with the enrichment of 5-methylcytosine and 5-hydroxymethylcytosine proximally at gene regulatory domains at the respective genes. A pharmacological strategy to reduce promoter hypermethylation and to induce a more permissive chromatin conformation is to administer drugs, such as the histone deacetylase (HDAC) inhibitor valproate (VPA), that facilitate chromatin remodeling. Studies in mouse models of SZ indicate that clozapine induces DNA demethylation at relevant promoters, and that this action is potentiated by VPA. By activating DNA demethylation, clozapine or its derivatives with VPA or other more potent and selective HDAC inhibitors may be a promising treatment strategy to correct the gene expression deficits detected in postmortem brain of SZ and BPD patients.
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Affiliation(s)
- Alessandro Guidotti
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Illinois, USA
| | - Dennis R Grayson
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Illinois, USA
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Backlund L, Wei YB, Martinsson L, Melas PA, Liu JJ, Mu N, Östenson CG, Ekström TJ, Schalling M, Lavebratt C. Mood Stabilizers and the Influence on Global Leukocyte DNA Methylation in Bipolar Disorder. MOLECULAR NEUROPSYCHIATRY 2015; 1:76-81. [PMID: 27602359 DOI: 10.1159/000430867] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/21/2015] [Indexed: 11/19/2022]
Abstract
Little is known about the relationship between treatments for bipolar disorder (BD), their therapeutic responses and the DNA methylation status. We investigated whether global DNA methylation levels differ between healthy controls and bipolar patients under different treatments. Global DNA methylation was measured in leukocyte DNA from bipolar patients under lithium monotherapy (n = 29) or combination therapy (n = 32) and from healthy controls (n = 26). Lithium response was assessed using the Alda scale. Lithium in monotherapy was associated with hypomethylation (F = 4.63, p = 0.036). Lithium + valproate showed a hypermethylated pattern compared to lithium alone (F = 7.27, p = 0.011). Lithium response was not associated with DNA methylation levels. These data suggest that the choice of treatment in BD may lead to different levels of global DNA methylation. However, further research is needed to understand its clinical significance.
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Affiliation(s)
- Lena Backlund
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Centre for Psychiatric Research and Education, Karolinska University Hospital, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Ya Bin Wei
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Lina Martinsson
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Philippe A Melas
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Jia Jia Liu
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden; School of Nursing, Shandong University, Jinan, China
| | - Ninni Mu
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Claes-Göran Östenson
- Endocrine and Diabetes Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Tomas J Ekström
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Martin Schalling
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Catharina Lavebratt
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
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Abdolmaleky HM, Zhou JR, Thiagalingam S. An update on the epigenetics of psychotic diseases and autism. Epigenomics 2015; 7:427-49. [DOI: 10.2217/epi.14.85] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The examination of potential roles of epigenetic alterations in the pathogenesis of psychotic diseases have become an essential alternative in recent years as genetic studies alone are yet to uncover major gene(s) for psychosis. Here, we describe the current state of knowledge from the gene-specific and genome-wide studies of postmortem brain and blood cells indicating that aberrant DNA methylation, histone modifications and dysregulation of micro-RNAs are linked to the pathogenesis of mental diseases. There is also strong evidence supporting that all classes of psychiatric drugs modulate diverse features of the epigenome. While comprehensive environmental and genetic/epigenetic studies are uncovering the origins, and the key genes/pathways affected in psychotic diseases, characterizing the epigenetic effects of psychiatric drugs may help to design novel therapies in psychiatry.
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Affiliation(s)
- Hamid Mostafavi Abdolmaleky
- Departments of Medicine (Biomedical Genetics Section), Genetics & Genomics, Boston University School of Medicine, Boston, MA 02118, USA
- Nutrition/Metabolism Laboratory at Beth Israel Deaconess Medical Center, Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Jin-Rong Zhou
- Nutrition/Metabolism Laboratory at Beth Israel Deaconess Medical Center, Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Sam Thiagalingam
- Departments of Medicine (Biomedical Genetics Section), Genetics & Genomics, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Pathology & Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
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25
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Shorter KR, Miller BH. Epigenetic mechanisms in schizophrenia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 118:1-7. [PMID: 25958205 DOI: 10.1016/j.pbiomolbio.2015.04.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 01/03/2023]
Abstract
Epigenetic modifications, including DNA methylation, histone modifications, and non-coding RNAs, have been implicated in a number of complex diseases. Schizophrenia and other major psychiatric and neurodevelopmental disorders are associated with abnormalities in multiple epigenetic mechanisms, resulting in altered gene expression during development and adulthood. Polymorphisms and copy number variants in schizophrenia risk genes contribute to the high heritability of the disease, but environmental factors that lead to epigenetic modifications may either reduce or exacerbate the expression of molecular and behavioral phenotypes associated with schizophrenia and related disorders. In the present paper, we will review the current understanding of molecular dysregulation in schizophrenia, including disruption of the dopamine, NMDA, and GABA signaling pathways, and discuss the role of epigenetic factors underlying disease pathology.
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Affiliation(s)
- Kimberly R Shorter
- McKnight Brain Institute and Departments of Psychiatry and Medicine, University of Florida College of Medicine, Gainesville, FL 32607, USA
| | - Brooke H Miller
- McKnight Brain Institute and Departments of Psychiatry and Medicine, University of Florida College of Medicine, Gainesville, FL 32607, USA.
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DNA methylation differences in monozygotic twin pairs discordant for schizophrenia identifies psychosis related genes and networks. BMC Med Genomics 2015; 8:17. [PMID: 25943100 PMCID: PMC4494167 DOI: 10.1186/s12920-015-0093-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 04/24/2015] [Indexed: 01/28/2023] Open
Abstract
Background Despite their singular origin, monozygotic twin pairs often display discordance for complex disorders including schizophrenia. It is a common (1%) and often familial disease with a discordance rate of ~50% in monozygotic twins. This high discordance is often explained by the role of yet unknown environmental, random, and epigenetic factors. The involvement of DNA methylation in this disease appears logical, but remains to be established. Methods We have used blood DNA from two pairs of monozygotic twins discordant for schizophrenia and their parents in order to assess genome-wide methylation using a NimbleGen Methylation Promoter Microarray. Results The genome-wide results show that differentially methylated regions (DMRs) exist between members representing discordant monozygotic twins. Some DMRs are shared with parent(s) and others appear to be de novo. We found twenty-seven genes affected by DMR changes that were shared in the affected member of two discordant monozygotic pairs from unrelated families. Interestingly, the genes affected by pair specific DMRs share specific networks. Specifically, this study has identified two networks; “cell death and survival” and a “cellular movement and immune cell trafficking”. These two networks and the genes affected have been previously implicated in the aetiology of schizophrenia. Conclusions The results are compatible with the suggestion that DNA methylation may contribute to the discordance of monozygotic twins for schizophrenia. Also, this may be accomplished by the direct effect of gene specific methylation changes on specific biological networks rather than individual genes. It supports the extensive genetic, epigenetic and phenotypic heterogeneity implicated in schizophrenia. Electronic supplementary material The online version of this article (doi:10.1186/s12920-015-0093-1) contains supplementary material, which is available to authorized users.
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Zong X, Hu M, Li Z, Cao H, Chen X, Tang J. DNA methylation in schizophrenia: progress and challenges. Sci Bull (Beijing) 2015. [DOI: 10.1007/s11434-014-0690-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Bosia M, Pigoni A, Cavallaro R. Genomics and epigenomics in novel schizophrenia drug discovery: translating animal models to clinical research and back. Expert Opin Drug Discov 2014; 10:125-39. [PMID: 25345474 DOI: 10.1517/17460441.2015.976552] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Schizophrenia is a major psychiatric disorder that afflicts about 1% of the world's population, falling into the top 10 medical disorders causing disability. Existing therapeutic strategies have had limited success; they have poor effects on core cognitive impairment and long-term disability. They are also burdened by relevant side effects. Although new antipsychotic medications have been launched in the past decades, there has been a general lack of significant innovation over the past 60 years. This lack of significant progress in the pharmacotherapy of schizophrenia is a reflection of the complexity and heterogeneity of its etiopathogenetic mechanisms. AREAS COVERED In this article, the authors briefly review genetic models of schizophrenia, focusing on examples of how new therapeutic strategies have been developed from them. They report on the evidence of epigenetic alterations in schizophrenia and their relevance to pharmacological studies. Further, they describe the implications of epigenetic mechanisms in the etiopathogenesis of the disease and the effects of current antipsychotic drugs on epigenetic processes. Finally, they provide their perspective of using epigenetic drugs for treating schizophrenia. EXPERT OPINION Current genetic and epigenetic studies are finally shedding light on the biomolecular mechanisms linked to the core pathogenetic alterations in schizophrenia, rather than just their symptoms. These advancements in the understanding of the physiopathology of schizophrenia provide exciting new perspectives for treatments. Indeed, the possibility of looking directly at the biomolecular level allows us to bypass the age-old issues of animal studies pertaining to their questionable validity as behavioral models.
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Affiliation(s)
- Marta Bosia
- IRCCS San Raffaele Scientific Institute, Department of Clinical Neurosciences , Via Stamira d'Ancona 20, 20127 Milano , Italy +390 226 433 218 ; +390 226 433 265 ;
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Brucato N, DeLisi LE, Fisher SE, Francks C. Hypomethylation of the paternally inherited LRRTM1 promoter linked to schizophrenia. Am J Med Genet B Neuropsychiatr Genet 2014; 165B:555-63. [PMID: 25111784 DOI: 10.1002/ajmg.b.32258] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 06/26/2014] [Indexed: 12/25/2022]
Abstract
Epigenetic effects on psychiatric traits remain relatively under-studied, and it remains unclear what the sizes of individual epigenetic effects may be, or how they vary between different clinical populations. The gene LRRTM1 (chromosome 2p12) has previously been linked and associated with schizophrenia in a parent-of-origin manner in a set of affected siblings (LOD = 4.72), indirectly suggesting a disruption of paternal imprinting at this locus in these families. From the same set of siblings that originally showed strong linkage at this locus, we analyzed 99 individuals using 454-bisulfite sequencing, from whole blood DNA, to measure the level of DNA methylation in the promoter region of LRRTM1. We also assessed seven additional loci that would be informative to compare. Paternal identity-by-descent sharing at LRRTM1, within sibling pairs, was linked to their similarity of methylation at the gene's promoter. Reduced methylation at the promoter showed a significant association with schizophrenia. Sibling pairs concordant for schizophrenia showed more similar methylation levels at the LRRTM1 promoter than diagnostically discordant pairs. The alleles of common SNPs spanning the locus did not explain this epigenetic linkage, which can therefore be considered as largely independent of DNA sequence variation and would not be detected in standard genetic association analysis. Our data suggest that hypomethylation at the LRRTM1 promoter, particularly of the paternally inherited allele, was a risk factor for the development of schizophrenia in this set of siblings affected with familial schizophrenia, and that had previously showed linkage at this locus in an affected-sib-pair context.
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Affiliation(s)
- Nicolas Brucato
- Language & Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
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Kinoshita M, Numata S, Tajima A, Ohi K, Hashimoto R, Shimodera S, Imoto I, Takeda M, Ohmori T. Aberrant DNA methylation of blood in schizophrenia by adjusting for estimated cellular proportions. Neuromolecular Med 2014; 16:697-703. [PMID: 25052007 DOI: 10.1007/s12017-014-8319-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 07/08/2014] [Indexed: 01/14/2023]
Abstract
DNA methylation, which is the transference of a methyl group to the 5'-carbon position of the cytosine in a CpG dinucleotide, is one of the major mechanisms of epigenetic modifications. A number of studies have demonstrated altered DNA methylation of peripheral blood cells in schizophrenia (SCZ) in previous studies. However, most of these studies have been limited to the analysis of the CpG sites in CpG islands in gene promoter regions, and cell-type proportions of peripheral leukocytes, which may be one of the potential confounding factors for DNA methylation, have not been adjusted in these studies. In this study, we performed a genome-wide DNA methylation profiling of the peripheral leukocytes from patients with SCZ and from non-psychiatric controls (N = 105; 63 SCZ and 42 control subjects) using a quantitative high-resolution DNA methylation microarray which covered across the whole gene region (485,764 CpG dinucleotides). In the DNA methylation data analysis, we first estimated the cell-type proportions of each sample with a published algorithm. Next, we performed a surrogate variable analysis to identify potential confounding factors in our microarray data. Finally, we conducted a multiple linear regression analysis in consideration of these factors, including estimated cell-type proportions, and identified aberrant DNA methylation in SCZ at 2,552 CpG loci at a 5% false discovery rate correction. Our results suggest that altered DNA methylation may be involved in the pathophysiology of SCZ, and cell heterogeneity adjustments may be necessary for DNA methylation analysis.
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Affiliation(s)
- Makoto Kinoshita
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-8-15, Kuramoto-cho, Tokushima, 770-8503, Japan,
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Bronfman ZZ, Ginsburg S, Jablonka E. Shaping the learning curve: epigenetic dynamics in neural plasticity. Front Integr Neurosci 2014; 8:55. [PMID: 25071483 PMCID: PMC4083220 DOI: 10.3389/fnint.2014.00055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 06/18/2014] [Indexed: 12/22/2022] Open
Abstract
A key characteristic of learning and neural plasticity is state-dependent acquisition dynamics reflected by the non-linear learning curve that links increase in learning with practice. Here we propose that the manner by which epigenetic states of individual cells change during learning contributes to the shape of the neural and behavioral learning curve. We base our suggestion on recent studies showing that epigenetic mechanisms such as DNA methylation, histone acetylation, and RNA-mediated gene regulation are intimately involved in the establishment and maintenance of long-term neural plasticity, reflecting specific learning-histories and influencing future learning. Our model, which is the first to suggest a dynamic molecular account of the shape of the learning curve, leads to several testable predictions regarding the link between epigenetic dynamics at the promoter, gene-network, and neural-network levels. This perspective opens up new avenues for therapeutic interventions in neurological pathologies.
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Affiliation(s)
- Zohar Z Bronfman
- The Cohn Institute for the History and Philosophy of Science and Ideas, Faculty of Humanities, Tel-Aviv University Tel-Aviv, Israel ; School of Psychology, Faculty of Social Science, Tel-Aviv University Tel-Aviv, Israel
| | - Simona Ginsburg
- Natural Science Department, The Open University of Israel Raanana, Israel
| | - Eva Jablonka
- The Cohn Institute for the History and Philosophy of Science and Ideas, Faculty of Humanities, Tel-Aviv University Tel-Aviv, Israel
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Gavin DP, Floreani C. Epigenetics of schizophrenia: an open and shut case. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 115:155-201. [PMID: 25131545 DOI: 10.1016/b978-0-12-801311-3.00005-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During the last decade and a half, there has been an explosion of data regarding epigenetic changes in schizophrenia. Most initial studies have suggested that schizophrenia is characterized by an overly restrictive chromatin state based on increases in transcription silencing histone modifications and DNA methylation at schizophrenia candidate gene promoters and increases in the expression of enzymes that catalyze their formation. However, recent studies indicate that the pathology is more complex. This complexity may greatly impact pharmacological approaches directed at targeting epigenetic abnormalities in schizophrenia. The current review explores epigenetic studies of schizophrenia and what this can tell us about the underlying pathophysiology. We hypothesize based on recent studies that it is also plausible that drugs that further restrict chromatin may be efficacious.
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Affiliation(s)
- David P Gavin
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA.
| | - Christina Floreani
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
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