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Tang L, Li J, Luo H, Bao M, Xiang J, Chen Y, Wang Y. The association of 5HT2A and 5HTTLPR polymorphisms with Alzheimer’s disease susceptibility: a meta-analysis with 6945 subjects. Oncotarget 2018; 9:15077-15089. [PMID: 29599928 PMCID: PMC5871099 DOI: 10.18632/oncotarget.23611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/15/2017] [Indexed: 11/25/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease. Relationships of 5HT2A and 5HTTLPR polymorphisms and AD risk have been widely investigated previously, whereas results derived from these studies were inconclusive and controversial. The aim of this study was to investigate the association of the 5-HT2A and 5HTTLPR polymorphisms and AD using a meta-analysis of existing literatures. Studies were collected using PubMed, Web of Science, the Cochrane Library databases, Chinese National Knowledge Infrastructure (CNKI) and Embase. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess associations. As a result, a total of 7 publications for 5-HT2A T102C and 16 publications for 5HTTLPR (L/S) comprised 3255 cases and 3690 controls fulfilled the inclusion criteria. Significant association was covered between allelic and recessive models of 5-HT2A T102C and AD (allelic model: p = 0.003, OR [95% CI] = 1.23 [1.07, 1.40]; recessive model: p = 0.03, OR [95% CI] = 1.28 [1.02, 1.59]). Subsequently, we conducted subgroup analysis for 5-HT2A T102C polymorphism based on ethnicities and APOE ε4, and identified a significantly increased risk for the allelic and dominant models of 5-HT2A T102C and AD in Asian subgroup (allelic model: p = 0.002, OR [95% CI] = 1.42 [1.14, 1.78]; dominant model: p = 0.02, OR [95% CI] = 1.60 [1.09, 2.35]) and subgroup without APOE ε4 (allelic model: p = 0.02, OR [95% CI] = 1.44 [1.05, 1.99]; dominant model: p = 0.0008, OR [95% CI] = 2.49 [1.46, 4.25]). Nevertheless, the pooled analyses suggested no significant association between allelic, dominant, and recessive models of 5HTTLPR (L/S) and AD (p > 0.05). In conclusion, our meta-analysis demonstrates that 5HT2A C10T, but not 5HTTLPR (L/S), might increase risk for AD.
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Affiliation(s)
- Liang Tang
- Department of Human Anatomy, Histology and Embryology, Institute of Neuroscience, Changsha Medical University, Changsha, PR China
- School of Basic Medical Science, Changsha Medical University, Changsha, PR China
| | - Jianming Li
- Department of Human Anatomy, Histology and Embryology, Institute of Neuroscience, Changsha Medical University, Changsha, PR China
- Department of Neurology, Xiang-Ya Hospital, Central South University, Changsha City, Hunan Province, PR China
| | - Huaiqing Luo
- Department of Human Anatomy, Histology and Embryology, Institute of Neuroscience, Changsha Medical University, Changsha, PR China
- School of Basic Medical Science, Changsha Medical University, Changsha, PR China
| | - Meihua Bao
- Department of Human Anatomy, Histology and Embryology, Institute of Neuroscience, Changsha Medical University, Changsha, PR China
- School of Basic Medical Science, Changsha Medical University, Changsha, PR China
| | - Ju Xiang
- Department of Human Anatomy, Histology and Embryology, Institute of Neuroscience, Changsha Medical University, Changsha, PR China
- School of Basic Medical Science, Changsha Medical University, Changsha, PR China
| | - Yiwei Chen
- Department of Human Anatomy, Histology and Embryology, Institute of Neuroscience, Changsha Medical University, Changsha, PR China
- School of Basic Medical Science, Changsha Medical University, Changsha, PR China
| | - Yan Wang
- Department of Human Anatomy, Histology and Embryology, Institute of Neuroscience, Changsha Medical University, Changsha, PR China
- School of Basic Medical Science, Changsha Medical University, Changsha, PR China
- Experiment Center for Function, Changsha Medical University, Changsha, PR China
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Yamazaki K, Yoshino Y, Mori T, Okita M, Yoshida T, Mori Y, Ozaki Y, Sao T, Iga JI, Ueno SI. Association Study and Meta-Analysis of Polymorphisms, Methylation Profiles, and Peripheral mRNA Expression of the Serotonin Transporter Gene in Patients with Alzheimer's Disease. Dement Geriatr Cogn Disord 2018; 41:334-47. [PMID: 27414430 DOI: 10.1159/000447324] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/01/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIM The aim of this study was to elucidate the relationship between Alzheimer's disease (AD) and the serotonin transporter gene (SLC6A4). METHODS AD subjects (n = 43) and controls (n = 47) were recruited and evaluated. In leukocytes, we evaluated two polymorphisms in SLC6A4, the serotonin transporter length polymorphic region (5-HTT-LPR) and rs25531, as well as methylation rates of the SLC6A4 promoter region and the SLC6A4 mRNA expression level. We also performed a meta-analysis to examine the relationship between the frequency of the L allele and the risk of AD. RESULTS The distributions of 5-HTT-LPR and rs25531 polymorphisms in AD subjects were not different from those of controls. Although the methylation rates in AD subjects were not significantly different from those of controls, the expression level in AD subjects was significantly higher than in controls. Additionally, the expression level in AD subjects was significantly correlated with apathy. Meta-analysis revealed that the L/L genotype significantly reduced the risk of AD, but only in the Caucasian population. CONCLUSION Higher SLC6A4 mRNA expression in leukocytes in AD was associated with apathy regardless of SLC6A4 genotypes and methylation rates of the promoter region. The L/L genotype may reduce the risk of AD in the Caucasian population.
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Affiliation(s)
- Kiyohiro Yamazaki
- Department of Neuropsychiatry, Molecules and Function, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Japan
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Abstract
Emerging research implicates a consistent reciprocal relationship between late-life anxiety and cognition. Understanding this relationship may clarify pathophysiological substrates of cognitive impairment and why co-occurring anxiety and cognitive impairment relates to poorer treatment prognosis for both conditions. This article critically reviews evidence of more prevalent anxiety in cognitively impaired older adults, elevated anxiety related to poorer cognitive performance, and more severe anxiety symptoms predicting future cognitive decline. It considers pathophysiologic mediators and moderators, and the influence of comorbid depression or medical illness in anxiety. Identified directions for future research includes use of in-depth anxiety assessment comparing normal and mild cognitively impaired older adults and use of challenging neuropsychological tests to determine if specific cognitive domains suffer in anxious older adults.
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Affiliation(s)
- Sherry A Beaudreau
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Veterans Affairs Palo Alto Health Care System, Clinical Center (MIRECC), Palo Alto, CA 94304, USA.
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Forero DA, Arboleda G, Yunis JJ, Pardo R, Arboleda H. Association study of polymorphisms in LRP1, tau and 5-HTT genes and Alzheimer’s disease in a sample of Colombian patients. J Neural Transm (Vienna) 2005; 113:1253-62. [PMID: 16362633 DOI: 10.1007/s00702-005-0388-z] [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] [Received: 04/13/2005] [Accepted: 09/10/2005] [Indexed: 10/25/2022]
Abstract
Analysis of genetic susceptibility factors for Alzheimer's disease (AD) in populations with different genetic and environmental background may be useful to understand AD etiology. There are few genetic association studies of AD in Latin America. In the present work, we analyzed polymorphisms in 3 candidate genes; the LDL receptor related protein-1, the microtubule-associated protein Tau and the serotonin transporter genes in a sample of 106 Colombian AD patients and 97 control subjects. We did not find a significant allelic or genotypic association with any of the three polymorphisms analyzed using different statistical analysis, including a neural network model or different sample stratifications. To date, APOE polymorphisms are the only genetic risk factors identified for AD in the Colombian population. It may be factible that future combination of high-throughput genotyping platforms and multivariate analysis models may lead to the identification of other genetic susceptibility factors for AD in the Colombian population.
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Affiliation(s)
- D A Forero
- Grupo de Neurociencias, Facultad de Medicina e Instituto de Genética, Universidad Nacional de Colombia, Bogotá, Colombia
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Nishimura AL, Guindalini C, Oliveira JRM, Nitrini R, Bahia VS, de Brito-Marques PR, Otto PA, Zatz M. Monoamine oxidase a polymorphism in Brazilian patients: risk factor for late-onset Alzheimer's disease? J Mol Neurosci 2005; 27:213-7. [PMID: 16186632 DOI: 10.1385/jmn:27:2:213] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Accepted: 03/30/2005] [Indexed: 11/11/2022]
Abstract
Different studies have attempted to find polymorphisms involved in the serotonergic pathway that could be involved in mood disorders and late-onset Alzheimer's disease (LOAD) symptoms. Here, we compared the frequency of two polymorphisms: monoamine oxidase A (MAOA) and serotonin transporter in LOAD patients versus controls. No evidence of association was observed when these polymorphisms were compared separately; however, the combination of the MAOA allele 1+the short allele of 5-HTTLPR+ApoE-epsilon4 was significantly more frequent in patients than in controls. It reinforces the hypothesis that different genes acting together might play a role in AD susceptibility. Based on these data, we suggest replicating these studies in larger samples of LOAD patients belonging to different ethnic groups.
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Affiliation(s)
- Agnes L Nishimura
- Human Genome Research Center, Biology Department, Institute of Biosciences, São Paulo University (IBUSP), São Paulo, Brazil
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Ha TM, Cho DM, Park SW, Joo MJ, Lee BJ, Kong BG, Kim JM, Yoon JS, Kim YH. Evaluating associations between 5-HTTLPR polymorphism and Alzheimer's disease for Korean patients. Dement Geriatr Cogn Disord 2005; 20:31-4. [PMID: 15832033 DOI: 10.1159/000085071] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/08/2004] [Indexed: 11/19/2022] Open
Abstract
There has been growing evidence that the serotonin (5-HT) system is important in the regulation of memory and thus might be associated with Alzheimer's disease (AD), while research results on this issue have been inconsistent. The 5-HT system has also been suggested to be responsible for a significant portion of the behavioural aspects of AD. This study aimed to investigate the associations of the 5-HT transporter gene linked polymorphic region (5-HTTLPR) polymorphism with AD and delusional/aggressive symptoms of AD in Korean samples of 65 patients and 43 controls. The 5-HTTLPR polymorphism was neither associated with AD nor with delusional/aggressive symptoms of AD. It was suggested that phenotypic expression of the 5-HTTLPR polymorphism might be varied according to ethnic differences.
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Affiliation(s)
- Tae Min Ha
- Department of Neuropsychiatry, School of Medicine, Busan, and Woosan Medical Foundation, Hyung Ju Hospital, Yangsan, Republic of Korea
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Manuck SB, Flory JD, Ferrell RE, Muldoon MF. Socio-economic status covaries with central nervous system serotonergic responsivity as a function of allelic variation in the serotonin transporter gene-linked polymorphic region. Psychoneuroendocrinology 2004; 29:651-68. [PMID: 15041087 DOI: 10.1016/s0306-4530(03)00094-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2002] [Accepted: 05/05/2003] [Indexed: 11/21/2022]
Abstract
It was reported recently that exposure to an adverse rearing environment lowers central nervous system (CNS) serotonergic activity in a nonhuman primate (rhesus monkeys), but only among animals having the shorter variant of a functional, biallelic repeat polymorphism in the regulatory region of the serotonin transporter (5-HTT) gene. Because repeat variants of the same core sequence affect transcriptional efficiency of the 5-HTT gene in humans, we examined whether biallelic variation in the 5-HTT gene-linked polymorphic region (5-HTTLPR) acts analogously to modulate a previously described association between socio-economic status (SES) and CNS serotonergic function. The 5-HTTLPR was genotyped in 139 adult men and women (n = 75 and 64) who were administered a standard neuroendocrine challenge to assess central serotonergic responsivity (plasma prolactin (PRL) response to the serotonin releasing agent, fenfluramine). Socio-economic status was estimated from reported income and years of education. Hierarchical linear regression showed serotonergic responsivity to be predicted by the interaction of 5-HTTLPR genotype and SES (p = 0.018). Individuals of lower income and less education had lower peak PRL concentrations following administration of fenfluramine than did subjects ranking higher on these dimensions, but only among persons possessing at least one 5-HTTLPR short allele. Within genotype, SES covaried moderately with the PRL response to fenfluramine among subjects who were homozygous for the short allele (r18 = 0.50, p < 0.03). A similar association was present at lesser magnitude in heterozygotes (r70 = 0.24, p < 0.05) and absent among subjects homozygous for the long allele (r45 = -0.04, n.s.). Findings were comparable for men and women and persisted on re-analysis restricted to persons without current Axis I psychopathology. We conclude that allelic variation at 5-HTTLPR moderates the influence of social position on CNS serotonergic responsivity.
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Affiliation(s)
- Stephen B Manuck
- Behavioral Physiology Laboratory, Department of Psychology, University of Pittsburgh, 506 EH, 4015 O'Hara Street, Pittsburgh, PA 15260, USA.
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Rocchi A, Micheli D, Ceravolo R, Manca ML, Tognoni G, Siciliano G, Murri L. Serotoninergic Polymorphisms (5-HTTLPR and 5-HT2A): Association Studies with Psychosis in Alzheimer Disease. ACTA ACUST UNITED AC 2003; 7:309-14. [PMID: 15000807 DOI: 10.1089/109065703322783662] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Patients with Alzheimer disease (AD) often exhibit psychotic symptoms associated with cognitive impairment. A few association studies have been carried out to determine if the serotonin transporter and receptor genes are potential risk factors for AD and/or associated psychopathology. The aim of this study was to investigate the association of a serotonin transporter gene-linked polymorphic region (5-HTTLPR) and the 5-HT2A receptor T102C polymorphism with the risk of developing dementia and/or psychotic symptoms in a group of sporadic AD patients from Italy. No significant differences in the distribution of allele and genotype frequencies of 5-HTTLPR and 5-HT2A T102C were found between patient and control groups. However, a significant association between the C102/C102 5-HT2A genotype and psychotic symptoms (p < 0.001) was observed. Our data strongly confirm results from previous studies suggesting that the C102 allele of the 5-HT2A receptor is associated with the occurrence of psychotic symptoms in AD. On the contrary, the serotonin transporter does not appear to be a major susceptibility factor in the pathophysiology of the disease.
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Affiliation(s)
- A Rocchi
- Department of Neuroscience - Neurological Clinics, University of Pisa, Pisa, Italy
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Rocchi A, Pellegrini S, Siciliano G, Murri L. Causative and susceptibility genes for Alzheimer's disease: a review. Brain Res Bull 2003; 61:1-24. [PMID: 12788204 DOI: 10.1016/s0361-9230(03)00067-4] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common type of dementia in the elderly population. Three genes have been identified as responsible for the rare early-onset familial form of the disease: the amyloid precursor protein (APP) gene, the presenilin 1 (PSEN1) gene and the presenilin 2 (PSEN2) gene. Mutations in these genes, however, account for less than 5% of the total number of AD cases. The remaining 95% of AD patients are mostly sporadic late-onset cases, with a complex aetiology due to interactions between environmental conditions and genetic features of the individual. In this paper, we review the most important genes supposed to be involved in the pathogenesis of AD, known as susceptibility genes, in an attempt to provide a comprehensive picture of what is known about the genetic mechanisms underlying the onset and progression of AD. Hypotheses about the role of each gene in the pathogenic pathway are discussed, taking into account the functions and molecular features, if known, of the coded protein. A major susceptibility gene, the apolipoprotein E (APOE) gene, found to be associated with sporadic late-onset AD cases and the only one, whose role in AD has been confirmed in numerous studies, will be included in a specific chapter. As the results reported by association studies are conflicting, we conclude that a better understanding of the complex aetiology that underlies AD may be achieved likely through a multidisciplinary approach that combines clinical and neurophysiological characterization of AD subtypes and in vivo functional brain imaging studies with molecular investigations of genetic components.
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Affiliation(s)
- A Rocchi
- Department of Neurosciences, Neurological Clinics, University of Pisa Medical School, Via Roma 67, 56126 Pisa, Italy
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