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Albert PR, Le François B, Vahid-Ansari F. Genetic, epigenetic and posttranscriptional mechanisms for treatment of major depression: the 5-HT1A receptor gene as a paradigm. J Psychiatry Neurosci 2019; 44:164-176. [PMID: 30807072 PMCID: PMC6488484 DOI: 10.1503/jpn.180209] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/10/2018] [Accepted: 12/21/2018] [Indexed: 02/07/2023] Open
Abstract
Major depression and anxiety are highly prevalent and involve chronic dysregulation of serotonin, but they remain poorly understood. Here, we review novel transcriptional (genetic, epigenetic) and posttranscriptional (microRNA, alternative splicing) mechanisms implicated in mental illness, focusing on a key serotonin-related regulator, the serotonin 1A (5-HT1A) receptor. Functional single-nucleotide polymorphisms and stress-induced DNA methylation of the 5-HT1A promoter converge to differentially alter pre- and postsynaptic 5-HT1A receptor expression associated with major depression and reduced therapeutic response to serotonergic antidepressants. Major depression is also associated with altered levels of splice factors and microRNA, posttranscriptional mechanisms that regulate RNA stability. The human 5-HT1A 3′-untranslated region is alternatively spliced, removing microRNA sites and increasing 5-HT1A expression, which is reduced in major depression and may be genotype-dependent. Thus, the 5-HT1A receptor gene illustrates the convergence of genetic, epigenetic and posttranscriptional mechanisms in gene expression, neurodevelopment and neuroplasticity, and major depression. Understanding gene regulatory mechanisms could enhance the detection, categorization and personalized treatment of major depression.
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Affiliation(s)
- Paul R. Albert
- From the Department of Neuroscience, Ottawa Hospital Research Institute, UOttawa Brain and Mind Research Institute, Ottawa, Ont., Canada
| | - Brice Le François
- From the Department of Neuroscience, Ottawa Hospital Research Institute, UOttawa Brain and Mind Research Institute, Ottawa, Ont., Canada
| | - Faranak Vahid-Ansari
- From the Department of Neuroscience, Ottawa Hospital Research Institute, UOttawa Brain and Mind Research Institute, Ottawa, Ont., Canada
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Plans L, Barrot C, Nieto E, Rios J, Schulze TG, Papiol S, Mitjans M, Vieta E, Benabarre A. Association between completed suicide and bipolar disorder: A systematic review of the literature. J Affect Disord 2019; 242:111-122. [PMID: 30173059 DOI: 10.1016/j.jad.2018.08.054] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/25/2018] [Accepted: 08/12/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Completed suicide is a major cause of death in bipolar disorder (BD) patients. OBJECTIVE The aim of this paper is to provide an overall review of the existing literature of completed suicide in BD patients, including clinical and genetic data DATA SOURCES: We performed a systematic review of English and non-English articles published on MEDLINE/PubMed, PsycInfo and Cochrane database (1970-2017). Additional studies were identified by contacting clinical experts, searching bibliographies, major textbooks and website of World Health Organization. Initially we did a broad search for the association of bipolar disorder and suicide and we were narrowing the search in terms included "bipolar disorder" and "completed suicide". STUDY SELECTION Inclusion criteria were articles about completed suicide in patients with BD. Articles exclusively focusing on suicide attempts and suicidal behaviour have been excluded. We used PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) consensus for drafting this systematic review. RESULTS The initial search generated 2806 articles and a total of 61 meeting our inclusion criteria. We reviewed epidemiological data, genetic factors, risk factors and treatment of completed suicide in BD. Suicide rates in BD vary between studies but our analyses show that they are approximately 20-30-fold greater than in general population. The highest risk of successful suicide was observed in BD-II subjects. The heritability of completed suicide is about 40% and some genes related to major neurotransmitter systems have been associated with suicide. Lithium is the only treatment that has shown anti-suicide potential. LIMITATIONS The most important limitation of the present review is the limited existing literature on completed suicide in BD. CONCLUSIONS BD patients are at high risk for suicide. It is possible to identify some factors related to completed suicide, such as early onset, family history of suicide among first-degree relatives, previous attempted suicides, comorbidities and treatment. However it is necessary to promote research on this serious health problem.
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Affiliation(s)
- L Plans
- Mental Health Division of Althaia, Xarxa Assistencial Universitària de Manresa, Catalonia, Spain
| | - C Barrot
- Forensic Genetic Laboratori, University of Barcelona, Catalonia, Spain
| | - E Nieto
- Mental Health Division of Althaia, Xarxa Assistencial Universitària de Manresa, Catalonia, Spain
| | - J Rios
- Universitat Autònoma de Barcelona, Laboratório de Bioestatística e Epidemiologia, Barcelona, Spain; Hospital Clínic, IDIBAPS, Bioestadística y Plataforma de Gestión de Datos, Barcelona, Spain
| | - T G Schulze
- Institute of Psychiatric Phenomics and Genomics (IPPG), University Hospital, Ludwig Maximilian University, Munich, Germany
| | - S Papiol
- Institute of Psychiatric Phenomics and Genomics (IPPG), University Hospital, Ludwig Maximilian University, Munich, Germany; Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilian University, Munich, Germany
| | - M Mitjans
- Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - E Vieta
- Bipolar Disorder Program, Hospital Clinic, University of Barcelona, IDIBAPS, CIBERSAM, Barcelona, Catalonia, Spain.
| | - A Benabarre
- Bipolar Disorder Program, Hospital Clinic, University of Barcelona, IDIBAPS, CIBERSAM, Barcelona, Catalonia, Spain
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Alizadeh N, Nosrat N, Jahani Z, Ahmadiani A, Asadi S, Shams J. Association of HTR1A gene polymorphisms with obsessive-compulsive disorder and its treatment response: the influence of sex and clinical characteristics. Int J Neurosci 2018; 129:264-272. [PMID: 30232922 DOI: 10.1080/00207454.2018.1526799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE There have been controversial results in the literature on the association between HTR1A polymorphisms (rs10042486, C-1019G, and Gly272Asp) and obsessive-compulsive disorder (OCD). Here, the plausibility for such genetic and pharmacogenetic association was investigated by assessing a sample of Iranian OCD patients. METHOD OCD patients had fulfilled the criteria for DSM-IV-TR with Y-BOCS scores higher than 9. A total of 207 controls and 205 patients' blood samples were genotyped by means of PCR-RFLP. RESULTS The results showed that there was no association between these three SNPs and the treatment response. The distribution of rs10042486 genotypes was significantly different in the patients compared to the controls. The association analyses of the C-1019G showed significant differences in the genotypic frequency of the patients with or without a positive family history of psychiatric disorders. Similar differences in female patients were also observed. We found that the age of onset also associates with the C-1019G polymorphism but only in the female patients. No association of Gly272Asp polymorphism and OCD was observed in this study. CONCLUSION We concluded that among the HTR1A polymorphisms, only the association of rs10042486 CT genotype and OCD was statistically significant. The association of C-1019G with OCD by considering the age of onset and family history was just significant in the female patients. No significant association between the studied HTR1A SNPs with treatment response was observed. Acquiring both positive and negative pharmacogenetic outcomes in each population helps to select the appropriate medication for a particular patient with fewer side effects.
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Affiliation(s)
- Niyousha Alizadeh
- a Neuroscience Research Center , Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Nasim Nosrat
- a Neuroscience Research Center , Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Zohreh Jahani
- a Neuroscience Research Center , Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Abolhassan Ahmadiani
- a Neuroscience Research Center , Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Sareh Asadi
- b NeuroBiology Research Center , Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Jamal Shams
- c Behavioral Sciences Research Center , Shahid Beheshti University of Medical Sciences , Tehran , Iran
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Philippe TJ, Vahid-Ansari F, Donaldson ZR, Le François B, Zahrai A, Turcotte-Cardin V, Daigle M, James J, Hen R, Merali Z, Albert PR. Loss of MeCP2 in adult 5-HT neurons induces 5-HT1A autoreceptors, with opposite sex-dependent anxiety and depression phenotypes. Sci Rep 2018; 8:5788. [PMID: 29636529 PMCID: PMC5893553 DOI: 10.1038/s41598-018-24167-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/27/2018] [Indexed: 12/11/2022] Open
Abstract
The 5-HT1A autoreceptor mediates feedback inhibition of serotonin (5-HT) neurons, and is implicated in major depression. The human 5-HT1A gene (HTR1A) rs6295 risk allele prevents Deaf1 binding to HTR1A, resulting in increased 5-HT1A autoreceptor transcription. Since chronic stress alters HTR1A methylation and expression, we addressed whether recruitment of methyl-binding protein MeCP2 may alter Deaf1 regulation at the HTR1A locus. We show that MeCP2 enhances Deaf1 binding to its HTR1A site and co-immunoprecipitates with Deaf1 in cells and brain tissue. Chromatin immunoprecipitation assays showed Deaf1-dependent recruitment of MeCP2 to the mouse HTR1A promoter, and MeCP2 modulated human and mouse HTR1A gene transcription in a Deaf1-dependent fashion, enhancing Deaf1-induced repression at the Deaf1 site. To address the role of MeCP2 in HTR1A regulation in vivo, mice with conditional knockout of MeCP2 in adult 5-HT neurons (MeCP2 cKO) were generated. These mice exhibited increased 5-HT1A autoreceptor levels and function, consistent with MeCP2 enhancement of Deaf1 repression in 5-HT neurons. Interestingly, female MeCP2-cKO mice displayed reduced anxiety, while males showed increased anxiety and reduced depression-like behaviors. These data uncover a novel role for MeCP2 in 5-HT neurons to repress HTR1A expression and drive adult anxiety- and depression-like behaviors in a sex-specific manner.
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Affiliation(s)
- Tristan J Philippe
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | - Faranak Vahid-Ansari
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | - Zoe R Donaldson
- Department of Molecular, Cellular, and Developmental Biology and Department of Psychology & Neuroscience, University of Colorado Boulder, Boulder, CO, USA
| | - Brice Le François
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | - Amin Zahrai
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | - Valérie Turcotte-Cardin
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | - Mireille Daigle
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | - Jonathan James
- The Royal's Institute of Mental Health, affiliated with the University of Ottawa, Ottawa, ON, Canada
| | - René Hen
- New York State Psychiatric Institute, Columbia University Medical Center and Research Foundation for Mental Hygiene, New York, NY, USA.,Department of Psychiatry, Columbia University, New York, NY, USA
| | - Zul Merali
- The Royal's Institute of Mental Health, affiliated with the University of Ottawa, Ottawa, ON, Canada
| | - Paul R Albert
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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McLaughlin PJ, Jagielo-Miller JE, Plyler ES, Schutte KK, Vemuri VK, Makriyannis A. Differential effects of cannabinoid CB1 inverse agonists and antagonists on impulsivity in male Sprague Dawley rats: identification of a possibly clinically relevant vulnerability involving the serotonin 5HT 1A receptor. Psychopharmacology (Berl) 2017; 234:1029-1043. [PMID: 28144708 DOI: 10.1007/s00213-017-4548-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/21/2017] [Indexed: 12/18/2022]
Abstract
RATIONALE Cannabinoid CB1 inverse agonists hold therapeutic promise as appetite suppressants but have produced suicidal behaviors among a small subpopulation in clinical trials. Anatomical and pharmacological evidence implicate the 5HT1A serotonin receptor in suicide in humans and impulsivity in humans and animals. OBJECTIVE The objective of the study is to assess whether 5HT1A blockade is necessary for CB1 ligands to produce impulsivity. METHODS Sprague Dawley rats were administered the CB1 inverse agonist AM 251, the CB1 antagonist AM 6527, or the peripherally restricted antagonist AM 6545, with or without pretreatment with the 5HT1A antagonist WAY 100,635 (WAY) on the paced fixed consecutive number (FCN) task, which measures choice to terminate a chain of responses prematurely. As FCN is sensitive to changes in time perception, which have been demonstrated with CB1 blockade, a novel variable consecutive number task with discriminative stimulus (VCN-S D ) was also performed and proposed to be less sensitive to changes in timing. RESULTS Pretreatment with WAY enabled mild but significant reductions in FCN accuracy for AM 251 and AM 6527. No effects were found for AM 6545. On the VCN-S D task, substantial impairments were found for the combination of WAY and AM 251. CONCLUSIONS AM 251, but not the antagonists AM 6527 or AM 6545, produced impulsivity only following systemic 5HT1A blockade. Although preliminary, the results may indicate that disrupted serotonin signaling produces a vulnerability to undesirable effects of CB1 inverse agonists, which is not evident in the general population. Furthermore, neutral CB1 antagonists do not produce this effect and therefore may have greater safety.
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Affiliation(s)
- Peter J McLaughlin
- Department of Psychology, Edinboro University of Pennsylvania, 210 East Normal Street, Edinboro, PA, 16444, USA.
| | - Julia E Jagielo-Miller
- Department of Psychology, Edinboro University of Pennsylvania, 210 East Normal Street, Edinboro, PA, 16444, USA.,Department of Psychology, University of Kentucky, Lexington, KY, 40506, USA
| | - Emily S Plyler
- Department of Psychology, Edinboro University of Pennsylvania, 210 East Normal Street, Edinboro, PA, 16444, USA.,Department of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - Kerry K Schutte
- Department of Psychology, Edinboro University of Pennsylvania, 210 East Normal Street, Edinboro, PA, 16444, USA.,Department of Counseling, Psychology, and Special Education, Duquesne University, 600 Forbes Avenue, G8B Canevin Hall, Pittsburgh, PA, 15282, USA
| | - V Kiran Vemuri
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA
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Mirkovic B, Laurent C, Podlipski MA, Frebourg T, Cohen D, Gerardin P. Genetic Association Studies of Suicidal Behavior: A Review of the Past 10 Years, Progress, Limitations, and Future Directions. Front Psychiatry 2016; 7:158. [PMID: 27721799 PMCID: PMC5034008 DOI: 10.3389/fpsyt.2016.00158] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/31/2016] [Indexed: 12/21/2022] Open
Abstract
Suicidal behaviors (SBs), which range from suicidal ideation to suicide attempts and completed suicide, represent a fatal dimension of mental ill-health. The involvement of genetic risk factors in SB is supported by family, twin, and adoption studies. The aim of this paper is to review recent genetic association studies in SBs including (i) case-control studies, (ii) family-based association studies, and (iii) genome-wide association studies (GWAS). Various studies on genetic associations have tended to suggest that a number of genes [e.g., tryptophan hydroxylase, serotonin receptors and transporters, or brain-derived neurotrophic factors (BDNFs)] are linked to SBs, but these findings are not consistently supported by the results obtained. Although the candidate-gene approach is useful, it is hampered by the present state of knowledge concerning the pathophysiology of diseases. Interpretations of GWAS results are mostly hindered by a lack of annotation describing the functions of most variation throughout the genome. Association studies have addressed a wide range of single-nucleotide polymorphisms in numerous genes. We have included 104 such studies, of which 10 are family-based association studies and 11 are GWAS. Numerous meta-analyses of case-control studies have shown significant associations of SB with variants in the serotonin transporter gene (5-HTT or SLC6A4) and the tryptophan hydroxylase 1 gene (TPH1), but others report contradictory results. The gene encoding BDNF and its receptor (NTRK2) are also promising candidates. Only two of the GWAS showed any significant associations. Several pathways are mentioned in an attempt to understand the lack of reproducibility and the disappointing results. Consequently, we review and discuss here the following aspects: (i) sample characteristics and confounding factors; (ii) statistical limits; (iii) gene-gene interactions; (iv) gene, environment, and by time interactions; and (v) technological and theoretical limits.
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Affiliation(s)
- Bojan Mirkovic
- Department of Child and Adolescent Psychiatry, CHU Charles Nicolle, Rouen, France; INSERM Unit U1079, Genetics of Cancer and Neurogenetics, University of Rouen, Rouen, France; Department of Child and Adolescent Psychiatry, Hôpital Pitié-Salpêtrière, Paris, France
| | - Claudine Laurent
- Department of Child and Adolescent Psychiatry, Hôpital Pitié-Salpêtrière, Paris, France; ICM - Brain and Spine Institute, Hôpital Pitié-Salpêtrière - University Pierre and Marie Curie, Paris, France
| | | | - Thierry Frebourg
- INSERM Unit U1079, Genetics of Cancer and Neurogenetics, University of Rouen, Rouen, France; Department of Genetics, CHU Charles Nicolle, Rouen, France
| | - David Cohen
- Department of Child and Adolescent Psychiatry, Hôpital Pitié-Salpêtrière, Paris, France; UMR 7222, Institute for Intelligent Systems and Robotics, University Pierre and Marie Curie, Paris, France
| | - Priscille Gerardin
- Department of Child and Adolescent Psychiatry, CHU Charles Nicolle, Rouen, France; Laboratoire Psy-NCA-EA-4700, University of Rouen, Rouen, France
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Rahn KA, Cao YJ, Hendrix CW, Kaplin AI. The role of 5-HT1A receptors in mediating acute negative effects of antidepressants: implications in pediatric depression. Transl Psychiatry 2015; 5:e563. [PMID: 25942044 PMCID: PMC4471288 DOI: 10.1038/tp.2015.57] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 01/20/2015] [Accepted: 02/10/2015] [Indexed: 01/20/2023] Open
Abstract
Acute antidepressant exposure elevates the frequency of impulsive behavior and suicidal thoughts in children and adolescents with major depressive disorder (MDD). Long-term antidepressant treatment, however, is beneficial for pediatric MDD, so it is necessary to explore novel treatments that prevent the potentially dangerous consequences of acute antidepressant initiation. In the present study, a treatment strategy designed to reverse the acute negative behavioral effects of antidepressants was tested in rodents. Co-administration of the 5-HT1A receptor (5-HT1AR) antagonist WAY-100635 reversed the negative effects of acute fluoxetine, a serotonin reuptake inhibitor, but not reboxetine, a norepinephrine reuptake inhibitor, supporting the involvement of 5-HT1AR in mediating the negative consequences of acute selective serotonin reuptake inhibitor (SSRI) treatment. No 5-HT1AR antagonists are currently approved for use in pediatric populations, so alternative strategies should be explored. One such strategy was suggested based on the hypothesis that the rate of 5-HT1AR activation and the subsequent inhibition of serotonergic neuron activity caused by acute SSRI administration is proportional to the loading rate of an antidepressant. Existing pharmacological data were examined, and significant correlations were observed between the half-life of antidepressants and the rate of suicide-related events (SREs). Specifically, antidepressants with longer half-lives have lower rates of SREs. On the basis of these data, novel dosing strategies were developed for five antidepressants to mimic the pharmacological profile of the antidepressant with the longest half-life, fluoxetine. These dosing strategies could be used to decrease the rate of SREs associated with acute antidepressant treatment in pediatric MDD until an improved pharmacological treatment is developed.
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Affiliation(s)
- K A Rahn
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, MD, USA,Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Y-J Cao
- Division of Clinical Pharmacology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - C W Hendrix
- Division of Clinical Pharmacology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - A I Kaplin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, MD, USA,Department of Neurology, Johns Hopkins University, Baltimore, MD, USA,Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, 600 North Wolfe Street, Meyer 1-121, Baltimore 21287, MD, USA. E-mail:
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González-Castro TB, Tovilla-Zárate CA, Juárez-Rojop I, Pool García S, Genis A, Nicolini H, López Narváez L. Association of 5HTR1A gene variants with suicidal behavior: case-control study and updated meta-analysis. J Psychiatr Res 2013; 47:1665-72. [PMID: 23911056 DOI: 10.1016/j.jpsychires.2013.04.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 04/06/2013] [Accepted: 04/11/2013] [Indexed: 11/17/2022]
Abstract
INTRODUCTION The gene encoding the serotonin 1A receptor (5HTR1A) has been a candidate gene associated with suicidal behavior in case-control and meta-analysis studies. We carried out a meta-analysis and a case-control study on the 5HTR1A gene to examine the association of this gene with suicidal behavior. METHODS We performed a systematic search in electronic databases to study meta-analytically the association of 5HTR1A gene with suicidal behavior; we found 9 published genetic association studies concerning the rs6295 polymorphism. To get a comprehensive knowledge of this association we conducted a case-control study on the following polymorphisms: rs1423691, rs6295, and rs878567 in a Mexican population; the sample was composed of 152 suicide attempters and 264 healthy subjects. RESULTS The meta-analysis revealed that the rs6295 polymorphism is not associated with suicidal behavior. Similarly, no significant association for polymorphisms rs6295 and rs878567 was found in the case-control study. The polymorphism rs1423691 was excluded of the association analysis because cases and control groups were in Hardy-Weinberg disequilibrium. CONCLUSION The meta-analysis of functional rs6295 polymorphisms produced no association. Likewise, the analysis in our case-control study in a Mexican population resulted in lack of association of polymorphisms rs6295 and rs878567 with suicidal behavior. However, further studies assessing different populations, as well as larger samples are necessary to obtain conclusive outcomes.
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Serotonergic genes and suicide: a systematic review. Eur Neuropsychopharmacol 2013; 23:1125-42. [PMID: 23742855 DOI: 10.1016/j.euroneuro.2013.03.013] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 02/12/2013] [Accepted: 03/24/2013] [Indexed: 12/12/2022]
Abstract
Suicide is one of the leading causes of death in the world. Its aetiology is complex and diverse, however, epidemiological studies show that suicidal behavior is partly heritable. Neurobiological evidence implicates serotonergic dysfunction in suicidality, stimulating genetic research to focus on genes related to the serotonergic system. In this paper, we review evidence from studies examining the association between various serotonergic genes (Tryptophan Hydroxylase genes: TPH1; TPH2, Serotonin Transporter gene: 5-HTTLPR in SLC6A4, Serotonin Receptor genes: HTR1A, HTR2A, HTR1B, HTR2C and Monoamine Oxidase A gene: MAOA) and suicidal behavior. The data show associations between variation on the TPH1 gene and 5-HTTLPR gene and violent suicidal behavior in Caucasian populations, with the least inconsistencies. Results are mixed for the TPH2 gene and serotonin receptor genes, but for some genes, studies that include haplotypic analyses or that examine a larger coding region of the genes tend to provide more reliable results. Findings on endophenotypes of suicidality, such as aggression and impulsivity traits, show positive associations for the TPH1, HTR2A, and MAOA genes, but need further replication, since negative associations are also occasionally reported. Since genes can only partially explain suicidal risk, several studies during the past decade have tried to incorporate environmental factors in the susceptibility model. Studies to date show that variation on the 5-HTTLPR, MAOA and HTR2A gene can interact with stressful life events to increase risk for suicidal behavior. Limitations of case-control studies are discussed and future considerations are put forward with regard to endophenotypic measurements and gene-environment interactions.
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