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Perić M, Bečeheli I, Čičin-Šain L, Desoye G, Štefulj J. Serotonin system in the human placenta - the knowns and unknowns. Front Endocrinol (Lausanne) 2022; 13:1061317. [PMID: 36531448 PMCID: PMC9751904 DOI: 10.3389/fendo.2022.1061317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 11/10/2022] [Indexed: 12/02/2022] Open
Abstract
The biogenic monoamine serotonin (5-hydroxytryptamine, 5-HT) is a chemical messenger widely distributed in the brain and various other organs. Its homeostasis is maintained by the coordinated activity of a variety of proteins, including enzymes of serotonin metabolism, transmembrane transporters of serotonin, and serotonin receptors. The serotonin system has been identified also in the placenta in rodent models as a key component of placental physiology. However, serotonin pathways in the human placenta are far from well understood. Their alterations may have long-lasting consequences for the fetus that can manifest later in life. In this review, we summarize information on the location of the components of the serotonin system in the human placenta, their regulation, function, and alterations in pathological pregnancies. We highlight current controversies and discuss important topics for future research.
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Affiliation(s)
- Maja Perić
- Laboratory of Neurochemistry and Molecular Neurobiology, Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ivona Bečeheli
- Laboratory of Neurochemistry and Molecular Neurobiology, Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Lipa Čičin-Šain
- Laboratory of Neurochemistry and Molecular Neurobiology, Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Gernot Desoye
- Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria
| | - Jasminka Štefulj
- Laboratory of Neurochemistry and Molecular Neurobiology, Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
- *Correspondence: Jasminka Štefulj,
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2
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Manzella C, Singhal M, Ackerman M, Alrefai WA, Saksena S, Dudeja PK, Gill RK. Serotonin transporter untranslated regions influence mRNA abundance and protein expression. GENE REPORTS 2020; 18. [PMID: 34113740 DOI: 10.1016/j.genrep.2019.100513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The serotonin transporter (SERT, SLC6A4) is a Na+-dependent transporter that regulates the availability of serotonin (5-HT, 5-hydroxytryptamine), a key neurotransmitter and hormone in the brain and the intestine. The human SERT gene consists of two alternate promoters that drive expression of an identical SERT protein. However, there are different mRNA transcript variants derived from these two promoters that differ in their 5' untranslated region (5'UTR), which is the region of the mRNA upstream from the protein-coding region. Two of these transcripts contain exon-1a and are abundant in neuronal tissue, whereas the third transcript contains exon-1c and is abundant in the intestine. The 3'UTR is nearly identical among the transcripts. Current studies tested the hypothesis that the UTRs of SERT influence its expression in intestinal epithelial cells (IECs) by controlling mRNA or protein levels. The SERT UTRs were cloned into luciferase reporter plasmids and luciferase mRNA and activity were measured following transient transfection of the UTR constructs into the model IEC Caco-2. Luciferase activity and mRNA abundance were higher than the empty vector for two of the three 5'UTR variants. Calculation of translation index (luciferase activity divided by the relative luciferase mRNA level) revealed that the exon-1a containing 5'UTRs had enhanced translation when compared to the exon-1c containing 5'UTR which exhibited a low translation efficiency. Compared to the empty vector, the SERT 3'UTR markedly decreased luciferase activity. In silico analysis of the SERT 3'UTR revealed many conserved potential miRNA binding sites that may be responsible for this decrease. In conclusion, we have shown that the UTRs of SERT regulate mRNA abundance and protein expression. Delineating the molecular basis by which the UTRs of SERT influence its expression will lead to an increased understanding of post-transcriptional regulation of SERT in GI disorders associated with altered 5-HT availability.
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Affiliation(s)
- Christopher Manzella
- Department of Physiology & Biophysics, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Megha Singhal
- Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Max Ackerman
- University of Illinois at Chicago, College of Liberal Arts and Sciences, United States of America
| | - Waddah A Alrefai
- Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, IL, United States of America.,Jesse Brown VA Medical Center, Chicago, IL, United States of America
| | - Seema Saksena
- Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, IL, United States of America.,Jesse Brown VA Medical Center, Chicago, IL, United States of America
| | - Pradeep K Dudeja
- Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, IL, United States of America.,Jesse Brown VA Medical Center, Chicago, IL, United States of America
| | - Ravinder K Gill
- Division of Gastroenterology & Hepatology, University of Illinois at Chicago, Chicago, IL, United States of America.,Jesse Brown VA Medical Center, Chicago, IL, United States of America
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Araos P, Vidal R, O'Shea E, Pedraz M, García-Marchena N, Serrano A, Suárez J, Castilla-Ortega E, Ruiz JJ, Campos-Cloute R, Santín LJ, Rodríguez de Fonseca F, Pavón FJ, Colado MI. Serotonin is the main tryptophan metabolite associated with psychiatric comorbidity in abstinent cocaine-addicted patients. Sci Rep 2019; 9:16842. [PMID: 31727978 PMCID: PMC6856167 DOI: 10.1038/s41598-019-53312-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 10/26/2019] [Indexed: 11/09/2022] Open
Abstract
The lack of effective treatments and a high rate of relapse in cocaine addiction constitute a major health problem. The present study was conducted to examine the expression of tryptophan-derived metabolites in the context of cocaine addiction and psychiatric comorbidity, which is common in addicted subjects. Abstinent patients with cocaine use disorder (CUD) and control subjects were recruited for a cross-sectional study. Participants were assessed with a semi-structured diagnostic interview (PRISM) based on DSM-IV-TR for substance and mental disorders. Plasma concentrations of tryptophan metabolites and their association with relevant CUD-related variables and psychiatric comorbidity were explored. We observed decreased plasma kynurenic acid concentrations in the cocaine group, however no associations between CUD-related variables and tryptophan-derived metabolites were found. In contrast, 5-HT concentrations were increased in CUD-patients and the diagnosis of different psychiatric disorders in the cocaine group was related to higher plasma 5-HT concentrations compared with non-comorbid patients. Therefore, while changes in plasma kynurenic acid concentrations appear to be directly associated with lifetime CUD, changes in 5-HT concentrations are associated with psychiatric comorbidity. These results emphasize the need to find potential biomarkers for a better stratification of cocaine-addicted patients in order to develop therapeutic approaches to prevent cocaine relapse.
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Affiliation(s)
- Pedro Araos
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain.,Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento. Facultad de Psicología, Universidad de Málaga (UMA), Málaga, Spain
| | - Rebeca Vidal
- Departamento Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Esther O'Shea
- Departamento Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - María Pedraz
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain
| | - Nuria García-Marchena
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain
| | - Antonia Serrano
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain
| | - Juan Suárez
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain
| | - Estela Castilla-Ortega
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain.,Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento. Facultad de Psicología, Universidad de Málaga (UMA), Málaga, Spain
| | | | | | - Luis J Santín
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento. Facultad de Psicología, Universidad de Málaga (UMA), Málaga, Spain
| | - Fernando Rodríguez de Fonseca
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain
| | - Francisco Javier Pavón
- Unidad Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Málaga, Spain.
| | - María Isabel Colado
- Departamento Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
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Latorre E, Mesonero JE, Harries LW. Alternative splicing in serotonergic system: Implications in neuropsychiatric disorders. J Psychopharmacol 2019; 33:1352-1363. [PMID: 31210090 DOI: 10.1177/0269881119856546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND The serotonergic system is a key component of physiological brain function and is essential for proper neurological activity. Numerous neuropsychiatric disorders are associated with deregulation of the serotonergic system. Accordingly, many pharmacological treatments are focused on modulation of this system. While providing a promising line of therapeutic moderation, these approaches may be complicated due to the presence of alternative splicing events for key genes in this pathway. Alternative splicing is a co-transcriptional process by which different mRNA transcripts can be produced from the same gene. These different isoforms may have diverse activities and functions, and their relative balance is often critical for the maintenance of homeostasis. Alternative splicing greatly increases the production of proteins, augmenting cell plasticity, and provides an important control point for regulation of gene expression. AIM The objective of this narrative review is to discuss the potential impact of alternative splicing of different components of the serotonergic system and speculate on their involvement in several neuropsychiatric disorders. CONCLUSIONS The specific role of each isoform in disease and their relative activities in the signalling pathways involved are yet to be determined. We need to gain a better understanding of the basis of alternative isoforms of the serotonergic system in order to fully understand their impact and be able to develop new effective pharmacological isoform-specific targets.
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Affiliation(s)
- Eva Latorre
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
- Instituto Agroalimentario de Aragón - IA2 (Universidad de Zaragoza - CITA), Zaragoza, Spain
| | - Jose Emilio Mesonero
- Instituto Agroalimentario de Aragón - IA2 (Universidad de Zaragoza - CITA), Zaragoza, Spain
- Departamento Farmacología y Fisiología, Facultad de Veterinaria, Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Universidad de Zaragoza, Zaragoza, Spain
| | - Lorna W Harries
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, UK
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Shajib MS, Baranov A, Khan WI. Diverse Effects of Gut-Derived Serotonin in Intestinal Inflammation. ACS Chem Neurosci 2017; 8:920-931. [PMID: 28288510 DOI: 10.1021/acschemneuro.6b00414] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The gut is the largest producer of serotonin or 5-hydroxytryptamine (5-HT) in the human body, and 5-HT has been recognized as an important signaling molecule in the gut for decades. There are two distinct sources of enteric 5-HT. Mucosal 5-HT is predominantly produced by enterochromaffin (EC) cells of the gastrointestinal (GI) tract, and neuronal 5-HT in the gut is produced by serotonergic neurons of the enteric nervous system (ENS). The quantity of mucosal 5-HT produced vastly eclipses the amount of neuronal 5-HT in the gut. Though it is difficult to separate the functions of neuronal and mucosal 5-HT, in the normal gut both types of enteric 5-HT work synergistically playing a prominent role in the maintenance of GI functions. In inflammatory conditions of the gut, like inflammatory bowel disease (IBD) recent studies have revealed new diverse functions of enteric 5-HT. Mucosal 5-HT plays an important role in the production of pro-inflammatory mediators from immune cells, and neuronal 5-HT provides neuroprotection in the ENS. Based on searches for terms such as "5-HT", "EC cell", "ENS", and "inflammation" in pubmed.gov as well as by utilizing pertinent reviews, the current review aims to provide an update on the role of enteric 5-HT and its immune mediators in the context of intestinal inflammation.
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Affiliation(s)
- Md. Sharif Shajib
- Farncombe Family Digestive Health Research Institute, Hamilton, Ontario L8S
4K1, Canada
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Adriana Baranov
- Farncombe Family Digestive Health Research Institute, Hamilton, Ontario L8S
4K1, Canada
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Waliul I. Khan
- Farncombe Family Digestive Health Research Institute, Hamilton, Ontario L8S
4K1, Canada
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario L8S 4K1, Canada
- Hamilton
Regional Laboratory Medicine Program, Hamilton Health Sciences, Hamilton, Ontario L8N 3Z5, Canada
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Iurescia S, Seripa D, Rinaldi M. Looking Beyond the 5-HTTLPR Polymorphism: Genetic and Epigenetic Layers of Regulation Affecting the Serotonin Transporter Gene Expression. Mol Neurobiol 2016; 54:8386-8403. [DOI: 10.1007/s12035-016-0304-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 11/16/2016] [Indexed: 01/01/2023]
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7
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Manoharan A, Rajkumar RP, Shewade DG, Sundaram R, Muthuramalingam A, Paul A. Evaluation of interleukin-6 and serotonin as biomarkers to predict response to fluoxetine. Hum Psychopharmacol 2016; 31:178-84. [PMID: 27018372 DOI: 10.1002/hup.2525] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/26/2015] [Accepted: 01/31/2016] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Only 30% of major depressive disorder (MDD) patients achieve complete remission with a serotonergic antidepressant (selective serotonin reuptake inhibitor). We investigated the potential of serotonin (5-HT) and interleukin-6 (IL-6) to serve as functional biomarkers of fluoxetine response. METHODS Serum IL-6 and 5-HT were measured in 73 MDD patients (39 responders and 34 non-responders) pre- and 6 weeks post-treatment and in 44 normal controls with ELISA. Fluoxetine and norfluoxetine were measured using LC MS/MS. RESULTS IL-6 levels were significantly higher in MDD patients when compared with controls (p < 0.01), and 5-HT levels were significantly lower in non-responders compared with controls (p = 0.0131). Pre- and post-treatment levels of both biomarkers individually and in combination did not significantly differ between responders and non-responders. Area under the receiver operating characteristics curve for the biomarkers was 0.5. Significant correlation was seen between the percentage change in IL-6 and percentage change in Hamilton Rating Scale for Depression score in responders. Fluoxetine and norfluoxetine concentrations were not significantly different in responders and non-responders, and there was no correlation between fluoxetine concentrations and percentage reduction in 5-HT from week 0 to 6. CONCLUSION 5-HT and IL-6 may not serve as useful markers of response to fluoxetine because of inconsistent results across different studies. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Aarthi Manoharan
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Ravi Philip Rajkumar
- Department of Psychiatry, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Deepak Gopal Shewade
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Rajan Sundaram
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Avin Muthuramalingam
- Department of Psychiatry, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Abialbon Paul
- Department of Clinical Pharmacology, Apollo Hospitals Enterprise Limited, Madurai, India
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8
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Yang J, Li MD. Association and interaction analyses of 5-HT3 receptor and serotonin transporter genes with alcohol, cocaine, and nicotine dependence using the SAGE data. Hum Genet 2014; 133:905-18. [PMID: 24590108 PMCID: PMC4055533 DOI: 10.1007/s00439-014-1431-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 02/16/2014] [Indexed: 12/29/2022]
Abstract
Previous studies have implicated genes encoding the 5-HT3AB receptors (HTR3A and HTR3B) and the serotonin transporter (SLC6A4), both independently and interactively, in alcohol (AD), cocaine (CD), and nicotine dependence (ND). However, whether these genetic effects also exist in subjects with comorbidities remains largely unknown. We used 1,136 African-American (AA) and 2,428 European-American (EA) subjects from the Study of Addiction: Genetics and Environment (SAGE) to determine associations between 88 genotyped or imputed variants within HTR3A, HTR3B, and SLC6A4 and three types of addictions, which were measured by DSM-IV diagnoses of AD, CD, and ND and the Fagerström Test for Nicotine Dependence (FTND), an independent measure of ND commonly used in tobacco research. Individual SNP-based association analysis revealed a significant association of rs2066713 in SLC6A4 with FTND in AA (β = -1.39; P = 1.6E - 04). Haplotype-based association analysis found one major haplotype formed by SNPs rs3891484 and rs3758987 in HTR3B that was significantly associated with AD in the AA sample, and another major haplotype T-T-G, formed by SNPs rs7118530, rs12221649, and rs2085421 in HTR3A, which showed significant association with FTND in the EA sample. Considering the biologic roles of the three genes and their functional relations, we used the GPU-based Generalized Multifactor Dimensionality Reduction (GMDR-GPU) program to test SNP-by-SNP interactions within the three genes and discovered two- to five-variant models that have significant impacts on AD, CD, ND, or FTND. Interestingly, most of the SNPs included in the genetic interaction model(s) for each addictive phenotype are either overlapped or in high linkage disequilibrium for both AA and EA samples, suggesting these detected variants in HTR3A, HTR3B, and SLC6A4 are interactively contributing to etiology of the three addictive phenotypes examined in this study.
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Affiliation(s)
- Jiekun Yang
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, 450 Ray C. Hunt Drive, Charlottesville, VA, 22903, USA
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9
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Abstract
Serotonin (5-HT) has been recognized for decades as an important signalling molecule in the gut, but it is still revealing its secrets. Novel gastrointestinal functions of 5-HT continue to be discovered, as well as distant actions of gut-derived 5-HT, and we are learning how 5-HT signalling is altered in gastrointestinal disorders. Conventional functions of 5-HT involving intrinsic reflexes include stimulation of propulsive and segmentation motility patterns, epithelial secretion and vasodilation. Activation of extrinsic vagal and spinal afferent fibres results in slowed gastric emptying, pancreatic secretion, satiation, pain and discomfort, as well as nausea and vomiting. Within the gut, 5-HT also exerts nonconventional actions such as promoting inflammation and serving as a trophic factor to promote the development and maintenance of neurons and interstitial cells of Cajal. Platelet 5-HT, originating in the gut, promotes haemostasis, influences bone development and serves many other functions. 5-HT3 receptor antagonists and 5-HT4 receptor agonists have been used to treat functional disorders with diarrhoea or constipation, respectively, and the synthetic enzyme tryptophan hydroxylase has also been targeted. Emerging evidence suggests that exploiting epithelial targets with nonabsorbable serotonergic agents could provide safe and effective therapies. We provide an overview of these serotonergic actions and treatment strategies.
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Ushijima K, Koyanagi S, Sato Y, Ogata T, Matsunaga N, Fujimura A, Ohdo S. Role of Activating Transcription Factor-4 in 24-Hour Rhythm of Serotonin Transporter Expression in the Mouse Midbrain. Mol Pharmacol 2012; 82:264-70. [DOI: 10.1124/mol.112.079079] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Vijayendran M, Beach SRH, Plume JM, Brody GH, Philibert RA. Effects of genotype and child abuse on DNA methylation and gene expression at the serotonin transporter. Front Psychiatry 2012; 3:55. [PMID: 22707942 PMCID: PMC3374463 DOI: 10.3389/fpsyt.2012.00055] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 05/18/2012] [Indexed: 11/13/2022] Open
Abstract
Altered regulation of the serotonin transporter (SLC6A4) is hypothesized to be a key event in many forms of neuropsychiatric illness, yet our understanding of the molecular mechanisms through which changes in gene function could lead to illness remains incomplete. In prior studies, we and others have demonstrated that methylation of CpG residues in the promoter associated CpG island alters SLC6A4 gene expression, that the extent of that DNA methylation in child abuse is genotype dependent, and that adverse childhood experiences such as child sex abuse are related to methylation. However, we have not examined whether these effects are splice variant specific, whether the association of methylation to gene expression varies as a function of genotype, and whether methylation in other SLC6A4 gene regions are more likely candidates for GxE effects. In the current investigation we measured methylation in lymphoblast DNA from 158 female subjects in the Iowa Adoption Studies at 16 CpG residues spread across the SLC6A4 locus, and analyzed their relationship to gene expression for two SLC6A4 splice variants. Methylation of two CpG residues in the shore of the CpG island (cg22584138 and cg05951817), a location immediately upstream from exon 1A, predicted gene expression for the splice variant containing Exon 1A + 1B. Methylation at two residues in the CpG island itself (cg 25769822 and cg05016953) was associated with total SLC6A4 expression. Examination of these four CpG residues indicated that methylation of cg22584138 was influenced by both genotype and sex abuse, whereas methylation of cg05016953 was influenced only by sex abuse history. Factors influencing methylation at other CpG dinucleotide pairs were not identified. We conclude that methylation effects on transcription may vary as a function of underlying gene motif and splice variant, and that the shore of CpG islands, upstream of TSS, may be of particular interest in examining environmental effects on methylation.
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Margoob MA, Mushtaq D. Serotonin transporter gene polymorphism and psychiatric disorders: is there a link? Indian J Psychiatry 2011; 53:289-99. [PMID: 22303036 PMCID: PMC3267339 DOI: 10.4103/0019-5545.91901] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Though still in infancy, the field of psychiatric genetics holds great potential to contribute to the development of new diagnostic and therapeutic options to treat these disorders. Among a large number of existing neurotransmitter systems, the serotonin system dysfunction has been implicated in many psychiatric disorders and therapeutic efficacy of many drugs is also thought to be based on modulation of serotonin. Serotonin transporter gene polymorphism is one of the most extensively studied polymorphisms in psychiatric behavioral genetics. In this article, we review the status of evidence for association between the serotonin gene polymorphism and some common mental disorders like affective disorders, post-traumatic stress disorder, obsessive-compulsive disorder, suicide, autism, and other anxiety and personality disorders. Going beyond traditional association studies, gene-environment interaction, currently gaining momentum, is also discussed in the review. While the existing information of psychiatric genetics is inadequate for putting into practice genetic testing in the diagnostic work-up of the psychiatric patient, if consistent in future research attempts, such results can be of great help to improve the clinical care of a vast majority of patients suffering from such disorders.
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Affiliation(s)
- Mushtaq A Margoob
- Department of Psychiatry, Institute of Mental Health and Neurosciences-Kashmir, Kashmir, India.
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Shumay E, Fowler JS, Volkow ND. Genomic features of the human dopamine transporter gene and its potential epigenetic States: implications for phenotypic diversity. PLoS One 2010; 5:e11067. [PMID: 20548783 PMCID: PMC2883569 DOI: 10.1371/journal.pone.0011067] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 05/18/2010] [Indexed: 02/06/2023] Open
Abstract
Human dopamine transporter gene (DAT1 or SLC6A3) has been associated with various brain-related diseases and behavioral traits and, as such, has been investigated intensely in experimental- and clinical-settings. However, the abundance of research data has not clarified the biological mechanism of DAT regulation; similarly, studies of DAT genotype-phenotype associations yielded inconsistent results. Hence, our understanding of the control of the DAT protein product is incomplete; having this knowledge is critical, since DAT plays the major role in the brain's dopaminergic circuitry. Accordingly, we reevaluated the genomic attributes of the SLC6A3 gene that might confer sensitivity to regulation, hypothesizing that its unique genomic characteristics might facilitate highly dynamic, region-specific DAT expression, so enabling multiple regulatory modes. Our comprehensive bioinformatic analyzes revealed very distinctive genomic characteristics of the SLC6A3, including high inter-individual variability of its sequence (897 SNPs, about 90 repeats and several CNVs spell out all abbreviations in abstract) and pronounced sensitivity to regulation by epigenetic mechanisms, as evident from the GC-bias composition (0.55) of the SLC6A3, and numerous intragenic CpG islands (27 CGIs). We propose that this unique combination of the genomic features and the regulatory attributes enables the differential expression of the DAT1 gene and fulfills seemingly contradictory demands to its regulation; that is, robustness of region-specific expression and functional dynamics.
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Affiliation(s)
- Elena Shumay
- Brookhaven National Laboratory, Medical Department, Upton, New York, United States of America
- * E-mail: (ES); (JSF); (NDV)
| | - Joanna S. Fowler
- Brookhaven National Laboratory, Medical Department, Upton, New York, United States of America
- * E-mail: (ES); (JSF); (NDV)
| | - Nora D. Volkow
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (ES); (JSF); (NDV)
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14
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Sugden K, Tichopad A, Khan N, Craig IW, D'Souza UM. Genes within the serotonergic system are differentially expressed in human brain. BMC Neurosci 2009; 10:50. [PMID: 19445671 PMCID: PMC2697991 DOI: 10.1186/1471-2202-10-50] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 05/15/2009] [Indexed: 01/06/2023] Open
Abstract
Background Serotonin is an important neurotransmitter with wide-ranging functions throughout the central nervous system. There is strong evidence to suggest that regulation of serotonergic gene expression might be related to genetic variability, and several studies have focused on understanding the functional effects of specific polymorphisms within these genes on expression levels. However, the combination of genotype together with gender and brain region could have an overall effect on gene expression. In this study, we report expression patterns of five serotonergic genes (TPH1, TPH2, 5-HT2A, 5-HT2C, 5-HTT) in seven different human post-mortem brain regions (superior frontal gyrus, superior temporal gyrus, striatum, cerebellum, hippocampus, midbrain and thalamus) using TaqMan™ real-time quantitative PCR. In addition, the effect of genotype and gender on their expression levels was determined. Results The data revealed that mRNA from the five genes investigated was detected in all brain regions and showed an overall significant difference in expression levels. Furthermore, the expression of 5-HT2C, 5-HT2A and TPH2 was found to be significantly different between the various brain regions. However, neither gender nor genotype showed significant effects on the expression levels of any of the genes assayed. Interestingly, TPH1 and TPH2 were expressed in all brain regions similarly except for within the striatum and cerebellum, where TPH1 was expressed at a significantly higher level than TPH2. Conclusion The effect of brain region has a greater influence on serotonergic gene expression than either genotype or gender. These data add to the growing body of evidence that effects of functional polymorphisms on gene expression in vitro are not observed ex vivo, and provide information that will aid in the design of expression studies of the serotonergic gene system within human post-mortem brain.
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Affiliation(s)
- Karen Sugden
- MRC Social, Genetic and Developmental Psychiatry (SGDP) Centre, Institute of Psychiatry, King's College London, UK.
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15
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Linden DR, White SL, Brooks EM, Mawe GM. Novel promoter and alternate transcription start site of the human serotonin reuptake transporter in intestinal mucosa. Neurogastroenterol Motil 2009; 21:534-41, e10-1. [PMID: 19222758 PMCID: PMC2722877 DOI: 10.1111/j.1365-2982.2008.01247.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Selective serotonin-reuptake inhibitors are therapies for psychological and bowel disorders, but produce adverse effects in the non-targeted system. To determine whether human serotonin-selective reuptake transporter (SERT) transcripts in the intestine are different from the brain, rapid amplification of cDNA ends, primer extension and RT-PCR assays were used to evaluate SERT transcripts from each region. Potential SLC6A4 gene promoter constructs were evaluated with a secreted alkaline phosphatase reporter assay. A novel transcript of the human SLC6A4 gene was discovered that predominates in the intestine, and differs from previous transcripts in the 5'-untranslated region. The distinct transcriptional start site and alternate promoter suggest that gastrointestinal SERT can be differentially regulated from brain SERT, may explain why the polymorphism in the previously identified promoter is associated with affective disorders, but not associated with gastrointestinal dysfunction, and suggest the intriguing possibility of the development of site-specific therapeutics for SERT regulation in the treatment of multiple disorders.
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Affiliation(s)
- D R Linden
- Department of Anatomy and Neurobiology, The University of Vermont College of Medicine, Burlington, VT 05405, USA
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16
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Bischoff SC, Mailer R, Pabst O, Weier G, Sedlik W, Li Z, Chen JJ, Murphy DL, Gershon MD. Role of serotonin in intestinal inflammation: knockout of serotonin reuptake transporter exacerbates 2,4,6-trinitrobenzene sulfonic acid colitis in mice. Am J Physiol Gastrointest Liver Physiol 2009; 296:G685-95. [PMID: 19095763 DOI: 10.1152/ajpgi.90685.2008] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Serotonin (5-HT) regulates peristaltic and secretory reflexes in the gut. The serotonin reuptake transporter (SERT; SLC6A4), which inactivates 5-HT, is expressed in the intestinal mucosa and the enteric nervous system. Stool water content is increased and colonic motility is irregular in mice with a targeted deletion of SERT. We tested the hypotheses that 5-HT plays a role in regulating intestinal inflammation and that the potentiation of serotonergic signaling that results from SERT deletion is proinflammatory. Rectal installation of 2,4,6-trinitrobenzene sulfonic acid (TNBS) was used to induce an immune-mediated colitis, which was compared in SERT knockout mice and littermate controls. Intestinal myeloperoxidase and histamine levels were significantly increased, whereas the survival rate and state of health were significantly decreased in TNBS-treated mice that lacked SERT. Deletion of SERT thus increases the severity of TNBS colitis. These data suggest that 5-HT and its SERT-mediated termination play roles in intestinal immune/inflammatory responses in mice.
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Affiliation(s)
- Stephan C Bischoff
- Department of Nutritional Medicine and Immunology, University of Hohenheim, D-70593 Stuttgart, Germany.
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17
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Colucci R, Blandizzi C, Bellini M, Ghisu N, Tonini M, Del Tacca M. The genetics of the serotonin transporter and irritable bowel syndrome. Trends Mol Med 2008; 14:295-304. [PMID: 18550438 DOI: 10.1016/j.molmed.2008.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 04/15/2008] [Accepted: 05/07/2008] [Indexed: 12/12/2022]
Abstract
Serotonin transporter (SERT) mediates the intracellular reuptake of released serotonin, thus regulating its biological functions. Abnormalities in serotonin reuptake can alter enteric serotonergic signalling, leading to sensory, motor and secretory gut dysfunctions, which contribute to the pathophysiology of irritable bowel syndrome (IBS). This relationship has fostered the use of selective serotonin reuptake inhibitors (SSRIs) in the treatment of IBS. Current data on the efficacy of SSRIs in IBS, association of the SERT gene promoter polymorphism 5-HTTLPR with IBS and the expression pattern of SERT in the intestinal mucosa of IBS patients are conflicting. Recent molecular studies have raised critical questions about multiple SERT mRNA transcripts in the human gut, the role of polymorphic SERT promoter in the regulation of enteric SERT expression and the ability of 5-HTTLPR to affect human SERT gene transcription. The present review highlights recent advances in SERT genetics, discusses their implications for potential therapeutic applications of SSRIs in IBS and presents original suggestions for future investigations.
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Affiliation(s)
- Rocchina Colucci
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa, Via Roma 55, I-56126, Pisa, Italy
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18
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Murphy DL, Lesch KP. Targeting the murine serotonin transporter: insights into human neurobiology. Nat Rev Neurosci 2008; 9:85-96. [DOI: 10.1038/nrn2284] [Citation(s) in RCA: 344] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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19
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O'Reilly KC, Trent S, Bailey SJ, Lane MA. 13-cis-Retinoic acid alters intracellular serotonin, increases 5-HT1A receptor, and serotonin reuptake transporter levels in vitro. Exp Biol Med (Maywood) 2007; 232:1195-203. [PMID: 17895527 DOI: 10.3181/0703-rm-83] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In addition to their established role in nervous system development, vitamin A and related retinoids are emerging as regulators of adult brain function. Accutane (13-cis-retinoic acid, isotretinoin) treatment has been reported to increase depression in humans. Recently, we showed that chronic administration of 13-cis-retinoic acid (13-cis-RA) to adolescent male mice increased depression-related behaviors. Here, we have examined whether 13-cis-RA regulates components involved in serotonergic neurotransmission in vitro. We used the RN46A-B14 cell line, derived from rat embryonic raphe nuclei. This cell line synthesizes serotonin (5-hydroxytryptamine, 5-HT) and expresses the 5-HT(1A) receptor and the serotonin reuptake transporter (SERT). Cells were treated with 0, 2.5, or 10 microM 13-cis-RA for 48 or 96 hrs, and the levels of 5-HT; its metabolite, 5-hydroxyindoleacetic acid (5HIAA); 5-HT(1A) receptor; and SERT were determined. Treatment with 13-cis-RA for 96 hrs increased the intracellular levels of 5-HT and tended to increase intra-cellular 5HIAA levels. Furthermore, 48 hrs of treatment with 2.5 and 10 microM 13-cis-RA significantly increased 5-HT(1A) protein to 168.5 +/- 20.0% and 148.7 +/- 2.2% of control respectively. SERT protein levels were significantly increased to 142.5 +/- 11.1% and 119.2 +/- 3.6% of control by 48 hrs of treatment with 2.5 and 10 microM of 13-cis-RA respectively. Increases in both 5-HT(1A) receptor and SERT proteins may lead to decreased serotonin availability at synapses. Such an effect of 13-cis-RA could contribute to the increased depression-related behaviors we have shown in mice.
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Affiliation(s)
- Kally C O'Reilly
- Institute of Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
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20
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Van Kerkhoven LAS, Laheij RJF, Jansen JBMJ. Meta-analysis: a functional polymorphism in the gene encoding for activity of the serotonin transporter protein is not associated with the irritable bowel syndrome. Aliment Pharmacol Ther 2007; 26:979-86. [PMID: 17877505 DOI: 10.1111/j.1365-2036.2007.03453.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Serotonin is associated with symptoms of the irritable bowel syndrome, its action is terminated by the serotonin transporter protein. AIM To assess the association between a functional polymorphism in the gene encoding for activity of the serotonin transporter protein and the irritable bowel syndrome. METHODS Meta-analysis of studies identified through a Medline, PubMed and Web of Science search, describing the prevalence of a polymorphism in the serotonin transporter gene creating long and short alleles. RESULTS Eight eligible studies described a total of 1034 patients with the irritable bowel syndrome, and 1377 healthy controls. Presence of the short allele is not associated with an increased risk for the irritable bowel syndrome: OR 1.0; 95% CI: 0.7-1.4 for homozygous subjects, and OR 1.0; 95% CI: 0.8-1.2 for homozygous subjects and heterozygotes together. Although Caucasians and Asians had diverging genotypic frequencies, no association with the shot allele and irritable bowel syndrome was observed in subgroups: Asians OR 1.2; 95% CI: 0.9-1.6 and OR 1.1; 95% CI: 0.2-5.9; Caucasians OR 0.9; 95% CI: 0.5-1.7 and OR 0.9; 95% CI: 0.7-1.2, respectively, for homozygous subjects alone and for homozygous subjects and heterozygotes together. CONCLUSION A genetic polymorphism in the gene encoding for activity of the serotonin transporter protein is not associated with the irritable bowel.
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Affiliation(s)
- L A S Van Kerkhoven
- Department of Gastroenterology and Hepatology, Radboud University, Nijmegen Medical Center, Nijmegen, The Netherlands.
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21
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Lim JE, Papp A, Pinsonneault J, Sadée W, Saffen D. Allelic expression of serotonin transporter (SERT) mRNA in human pons: lack of correlation with the polymorphism SERTLPR. Mol Psychiatry 2006; 11:649-62. [PMID: 16432527 DOI: 10.1038/sj.mp.4001797] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An insertion/deletion polymorphism in the SERT linked promoter region (SERTLPR), previously reported to regulate mRNA expression in vitro, has been associated with mental disorders and response to psychotropic drugs. Contradictory evidence, however, has raised questions about the role of SERTLPR in regulating mRNA expression in vivo. We have used analysis of allelic expression imbalance (AEI) of SERT mRNA to assess quantitatively the contribution of SERTLPR to mRNA expression in human post-mortem pons tissue sections containing serotonergic neurons of the dorsal and median raphe nuclei. Any difference in the expression of one allele over the other indicates the presence of cis-acting elements that differentially affect transcription and/or mRNA processing and turnover. Using a marker SNP in the 3' untranslated region of SERT mRNA, statistically significant differences in allelic mRNA levels were detected in nine out of 29 samples heterozygous for the marker SNP. While the allelic expression differences were relatively small (15-25%), they could nevertheless be physiologically relevant. Although previous results had suggested that the long form of SERTLPR yields higher mRNA levels than the short form, we did not observe a correlation between SERTLPR and allelic expression ratios. Also in contrast to previous results, we found no correlation between SERTLPR and allelic expression ratios or SERT mRNA levels in B-lymphocytes. This study demonstrates that regulation of SERT mRNA is independent of SERTLPR, but could be associated with polymorphisms in partial linkage disequilibrium with SERTLPR.
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Affiliation(s)
- J-E Lim
- Department of Pharmacology, College of Medicine and Public Health, The Ohio State University, Columbus, 43210, USA
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22
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Lesch KP, Mössner R. Inactivation of 5HT transport in mice: modeling altered 5HT homeostasis implicated in emotional dysfunction, affective disorders, and somatic syndromes. Handb Exp Pharmacol 2006:417-56. [PMID: 16722245 DOI: 10.1007/3-540-29784-7_18] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Animal models have not only become an essential tool for investigating the neurobiological function of genes that are involved in the etiopathogenesis of human behavioral and psychiatric disorders but are also fundamental in the development novel therapeutic strategies. As an example, inactivation of the serotonin (5HT) transporter (5Htt, Slc6a4) gene in mice expanded our view of adaptive 5HT uptake regulation and maintenance of 5HT homeostasis in the developing human brain and molecular processes underlying anxiety-related traits, as well as affective spectrum disorders including depression. 5Htt-deficient mice have been employed as a model complementary to direct studies of genetically complex traits and disorders, with important findings in biochemical, morphological, behavioral, and pharmacological areas. Based on growing evidence for a critical role of the 5HTT in the integration of synaptic connections in the rodent, nonhuman primate, and human brain during critical periods of development and adult life, more in-depth knowledge of the molecular mechanisms implicated in these fine-tuning processes is currently evolving. Moreover, demonstration of a joint influence of the 5HTT variation and environmental sources during early brain development advanced our understanding of the mechanism of genexgene and genexenvironment interactions in the developmental neurobiology of anxiety and depression. Lastly, imaging techniques, which become increasingly elaborate in displaying the genomic influence on brain system activation in response to environmental cues, have provided the means to bridge the gap between small effects of 5HTT variation and complex behavior, as well as psychopathological dimensions. The combination of elaborate genetic, epigenetic, imaging, and behavioral analyses will continue to generate new insight into 5HTT's role as a master control gene of emotion regulation.
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Affiliation(s)
- K P Lesch
- Molecular and Clinical Psychobiology, Department of Psychiatry and Psychotherapy, University of Würzburg, Füchsleinstr. 15, 97080 Würzburg, Germany.
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23
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Prasad HC, Zhu CB, McCauley JL, Samuvel DJ, Ramamoorthy S, Shelton RC, Hewlett WA, Sutcliffe JS, Blakely RD. Human serotonin transporter variants display altered sensitivity to protein kinase G and p38 mitogen-activated protein kinase. Proc Natl Acad Sci U S A 2005; 102:11545-50. [PMID: 16055563 PMCID: PMC1183547 DOI: 10.1073/pnas.0501432102] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Accepted: 06/08/2005] [Indexed: 12/31/2022] Open
Abstract
Human serotonin [5-hydroxytryptamine (5-HT)] transporters (hSERT, 5HTT, and SLC6A4) inactivate 5-HT after release and are prominent targets for therapeutic intervention in mood, anxiety, and obsessive-compulsive disorders. Multiple hSERT coding variants have been identified, although to date no comprehensive functional analysis of these variants has been reported. We transfected hSERT or 10 hSERT coding variants and examined total and surface protein expression, antagonist recognition, and transporter modulation by posttranslational, regulatory pathways. Two variants, Pro339Leu and Ile425Val, demonstrated significant changes in surface expression supporting alterations in 5-HT transport capacity (V(max)). Regardless of basal transport activity, all SERT variants displayed a capacity for rapid, phorbol ester-triggered down-regulation. Remarkably, five variants (Thr4Ala, Gly56Ala, Glu215Lys, Lys605Asn, and Pro612Ser) demonstrated no capacity for 5-HT uptake stimulation after acute protein kinase G (PKG)/p38 mitogen-activated protein kinase (MAPK) activation. Epstein-Barr virus (EBV)-transformed lymphocytes natively expressing the most common of these variants (Gly56Ala) exhibited a similar loss of 5-HT uptake stimulation by PKG/p38 MAPK activators. HeLa cells transfected with the Gly56Ala variant demonstrated elevated basal phosphorylation and, unlike hSERT, could not be further phosphorylated after 8-bromo cGMP (8BrcGMP) treatments. These studies reveal cellular phenotypes associated with naturally occurring human SERT coding variants and suggest that altered transporter regulation by means of PKG/p38 MAPK-linked pathways may influence risk for disorders attributed to compromised 5-HT signaling.
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Affiliation(s)
- Harish C Prasad
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, USA
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Lesch KP, Gutknecht L. Pharmacogenetics of the serotonin transporter. Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:1062-73. [PMID: 15951088 DOI: 10.1016/j.pnpbp.2005.03.012] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2005] [Indexed: 11/22/2022]
Abstract
Response to psychopharmacologic drugs is genetically complex, results from an interplay of multiple genomic variations with environmental influences, and depends on the structure or functional expression of gene products, which are direct drug targets or indirectly modify the development and synaptic plasticity of neural networks critically involved in their effects. During brain development, the serotonin (5HT) system, which is commonly targeted by antidepressant, anxiolytic, and antipsychotic drugs, controls neuronal specification, differentiation, and phenotype maintenance. While formation and integration of these neural networks is dependent on the action of multiple proteins, converging lines of evidence indicate that genetically controlled variability in the expression of the 5HT transporter (5HTT) is critical to the development and plasticity of distinct neurocircuits. The most promising finding to date indicate an association between the response time as well as overall response to serotonin reuptake inhibitors (SSRIs) and a common polymorphism (5HTTLPR) within the transcriptional control region of the 5HTT gene (SLC6A4) in patients with depressive disorders. The formation and maturation of serotonergic and associated systems, in turn, are influencing the efficacy of serotonergic compounds in a variety of psychiatric conditions. Based on the notion that complex gene x gene and gene x environment interactions in the regulation of brain plasticity are presumed to contribute to individual differences in psychopharmacologic drug response, the concept of developmental psychopharmacogenetics is emerging.
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Affiliation(s)
- Klaus Peter Lesch
- Molecular and Clinical Psychobiology, Department of Psychiatry and Psychotherapy, University of Wuerzburg, Fuechsleinstr. 15, 97080 Wuerzburg, Germany.
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Reyes-Haro D, García-Alcocer G, Miledi R, García-Colunga J. Uptake of serotonin by adult rat corpus callosum is partially reduced by common antidepressants. J Neurosci Res 2003; 74:97-102. [PMID: 13130511 DOI: 10.1002/jnr.10724] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The corpus callosum (CC) is the main white matter tract involved in interhemispheric brain communication. We establish that uptake of [3H]5-hydroxytryptamine (5-HT) in CC is partially inhibited by some antidepressants. Slices of the adult rat CC had a high-affinity uptake of 5-HT. About 80% of this uptake was Na+ dependent, with a Michaelis-Menten constant, Km, of 420 +/- 80 nM and a rate of 5-HT uptake, Vmax, of 9.5 +/- 0.8 pmol/mg protein/min. The 5-HT uptake was reduced approximately 60% at pH 5 compared with that at pH 7. Fluoxetine (Prozac) inhibited only 43% of 5-HT uptake in a concentration-dependent manner, with an affinity constant, Ki, of 44.7 +/- 10.0 nM. We also studied the effects of other monoamine uptake inhibitors, all at 10 microM, and found that zimelidine, imipramine, and clomipramine inhibited 5-HT uptake in the CC by approximately 30-40%. The fluoxetine-insensitive 5-HT uptake was not altered by high concentrations of dopamine plus norepinephrine. The present data show that Na(+)-dependent 5-HT uptake occurs in the CC and optic nerve and that this uptake is partially sensitive to antidepressants and probably mediated by the serotonin transporter, which may be relevant during depression.
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Affiliation(s)
- Daniel Reyes-Haro
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Juriquilla, Querétaro, México
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