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James LM, Charonis SA, Georgopoulos AP. Schizophrenia, Human Leukocyte Antigen (HLA), and Herpes Viruses: Immunogenetic Associations at the Population Level. Neurosci Insights 2023; 18:26331055231166411. [PMID: 37077512 PMCID: PMC10108429 DOI: 10.1177/26331055231166411] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 03/13/2023] [Indexed: 04/21/2023] Open
Abstract
Several factors have been implicated in schizophrenia (SZ), including human herpes viruses (HHV) and the adaptive immunity Human Leukocyte Antigen (HLA) genes. Here we investigated these issues in 2 complementary ways. In one analysis, we evaluated SZ-HLA and HHV-HLA associations at the level of a single allele by computing (a) a SZ-HLA protection/susceptibility (P/S) score based on the covariance between SZ and 127 HLA allele prevalences in 14 European countries, (b) estimating in silico HHV-HLA best binding affinities for the 9 HHV strains, and (c) evaluating the dependence of P/S score on HHV-HLA binding affinities. These analyses yielded (a) a set of 127 SZ-HLA P/S scores, varying by >200× (maximum/minimum), which could not be accounted for by chance, (b) a set of 127 alleles × 9 HHV best-estimated affinities, varying by >600×, and (c) a set of correlations between SZ-HLA P/S scores and HHV-HLA binding which indicated a prominent role of HHV1. In a subsequent analysis, we extended these findings to the individual person by taking into account the fact that every individual carries 12 HLA alleles and computed (a) the average SZ-HLA P/S scores of 12 randomly chosen alleles (2 per gene), an indicator of HLA-based SZ P/S for an individual, and (b) the average of the corresponding HHV estimated affinities for those alleles, an indicator of overall effectiveness of HHV-HLA binding. We found (a) that HLA protection for SZ was significantly more prominent than susceptibility, and (b) that protective SZ-HLA scores were associated with higher HHV-HLA binding affinities, indicating that HLA binding and subsequent elimination of several HHV strains may confer protection against schizophrenia.
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Affiliation(s)
- Lisa M James
- The HLA Research Group, Department of Veterans Affairs Health Care System, Brain Sciences Center, Minneapolis, MN, USA
- Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN, USA
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN, USA
- Lisa M James, Brain Sciences Center (11B), Minneapolis VAHCS, One Veterans Drive, Minneapolis, MN 55417, USA.
| | - Spyros A Charonis
- The HLA Research Group, Department of Veterans Affairs Health Care System, Brain Sciences Center, Minneapolis, MN, USA
- Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Apostolos P Georgopoulos
- The HLA Research Group, Department of Veterans Affairs Health Care System, Brain Sciences Center, Minneapolis, MN, USA
- Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN, USA
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN, USA
- Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, USA
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2
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Gene-Environment Interactions in Schizophrenia: A Literature Review. Genes (Basel) 2021; 12:genes12121850. [PMID: 34946799 PMCID: PMC8702084 DOI: 10.3390/genes12121850] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/17/2021] [Accepted: 11/22/2021] [Indexed: 12/12/2022] Open
Abstract
Schizophrenia is a devastating mental illness with a strong genetic component that is the subject of extensive research. Despite the high heritability, it is well recognized that non-genetic factors such as certain infections, cannabis use, psychosocial stress, childhood adversity, urban environment, and immigrant status also play a role. Whenever genetic and non-genetic factors co-exist, interaction between the two is likely. This means that certain exposures would only be of consequence given a specific genetic makeup. Here, we provide a brief review of studies reporting evidence of such interactions, exploring genes and variants that moderate the effect of the environment to increase risk of developing psychosis. Discovering these interactions is crucial to our understanding of the pathogenesis of complex disorders. It can help in identifying individuals at high risk, in developing individualized treatments and prevention plans, and can influence clinical management.
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Anti-cyomegalovirus antibodies in schizophrenia and related disorders: A systematic review and meta-analysis. Schizophr Res 2021; 228:322-323. [PMID: 33497907 DOI: 10.1016/j.schres.2020.12.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/22/2020] [Accepted: 12/30/2020] [Indexed: 11/20/2022]
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Le TT, Dawkins BA, McKinney BA. Nearest-neighbor Projected-Distance Regression (NPDR) for detecting network interactions with adjustments for multiple tests and confounding. Bioinformatics 2020; 36:2770-2777. [PMID: 31930389 DOI: 10.1093/bioinformatics/btaa024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/24/2019] [Accepted: 01/08/2020] [Indexed: 12/13/2022] Open
Abstract
SUMMARY Machine learning feature selection methods are needed to detect complex interaction-network effects in complicated modeling scenarios in high-dimensional data, such as GWAS, gene expression, eQTL and structural/functional neuroimage studies for case-control or continuous outcomes. In addition, many machine learning methods have limited ability to address the issues of controlling false discoveries and adjusting for covariates. To address these challenges, we develop a new feature selection technique called Nearest-neighbor Projected-Distance Regression (NPDR) that calculates the importance of each predictor using generalized linear model regression of distances between nearest-neighbor pairs projected onto the predictor dimension. NPDR captures the underlying interaction structure of data using nearest-neighbors in high dimensions, handles both dichotomous and continuous outcomes and predictor data types, statistically corrects for covariates, and permits statistical inference and penalized regression. We use realistic simulations with interactions and other effects to show that NPDR has better precision-recall than standard Relief-based feature selection and random forest importance, with the additional benefit of covariate adjustment and multiple testing correction. Using RNA-Seq data from a study of major depressive disorder (MDD), we show that NPDR with covariate adjustment removes spurious associations due to confounding. We apply NPDR to eQTL data to identify potentially interacting variants that regulate transcripts associated with MDD and demonstrate NPDR's utility for GWAS and continuous outcomes. AVAILABILITY AND IMPLEMENTATION Available at: https://insilico.github.io/npdr/. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Trang T Le
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Brett A McKinney
- Department of Mathematics.,Tandy School of Computer Science, University of Tulsa, Tulsa, OK 74104, USA
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Kirkpatrick B, Gürbüz Oflezer Ö, Delice Arslan M, Hack G, Fernandez-Egea E. An Early Developmental Marker of Deficit versus Nondeficit Schizophrenia. Schizophr Bull 2019; 45:1331-1335. [PMID: 31423529 PMCID: PMC6811833 DOI: 10.1093/schbul/sbz024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
People with schizophrenia and primary negative symptoms (deficit schizophrenia) differ from those without such symptoms (nondeficit schizophrenia) on risk factors, course of illness, other signs and symptoms, treatment response, and biological correlates. These differences suggest that the 2 groups may also have developmental differences. A previous study found that people with schizophrenia have a wider palate than comparison subjects. We tested the hypothesis that those with deficit and nondeficit schizophrenia would differ on palate width. A dentist made blinded measurements of palate shape in deficit (N = 21) and nondeficit (N = 25) patients and control subjects (N = 127), matched for age and gender. The deficit group had significantly wider palates than either nondeficit or control subjects (respective means [standard deviation] 37.5 [3.9], 33.7 [3.1], and 34.0 [2.9]; P < .001 for both deficit/nondeficit and deficit/control comparisons, respective effect sizes 1.08 and 1.01). The nondeficit/control difference in width was not significant (P = .83), and there were no significant group differences in length or depth. The power to detect a nondeficit/control difference in width equal in size to that of the deficit/control difference in width (3.5 mm) was 0.99 and 0.92 for a 2.0-mm difference. This difference in palate width may reflect a divergence in development between deficit and nondeficit patients that occurs by the early second trimester and is consistent with the hypothesis that deficit schizophrenia is a separate disease within the syndrome of schizophrenia.
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Affiliation(s)
- Brian Kirkpatrick
- Department of Psychiatry and Behavioral Sciences, University of Nevada, Reno School of Medicine, Reno, Nevada,To whom correspondence should be addressed; tel: 775-682-8455, fax: 775-784-1428, e-mail:
| | - Özlem Gürbüz Oflezer
- Department of Prosthetic Dentistry, Ministry of Health, Istanbul Bahcelievler Oral and Dental Hospital, Istanbul, Turkey
| | - Mehtap Delice Arslan
- Department of Psychiatry, Bakirkoy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Istanbul, Turkey
| | - Gary Hack
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, Maryland
| | - Emilio Fernandez-Egea
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK,Department of Psychiatry and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK,Centro de Investigación Biomédica en Red, Área de Salud Mental (CIBERSAM), Barcelona, Spain
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Severance EG, Yolken RH. Deciphering microbiome and neuroactive immune gene interactions in schizophrenia. Neurobiol Dis 2018; 135:104331. [PMID: 30471416 DOI: 10.1016/j.nbd.2018.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/29/2018] [Accepted: 11/19/2018] [Indexed: 02/07/2023] Open
Abstract
The body's microbiome represents an actively regulated network of novel mechanisms that potentially underlie the etiology and pathophysiology of a wide range of diseases. For complex brain disorders such as schizophrenia, understanding the cellular and molecular pathways that intersect the bidirectional gut-brain axis is anticipated to lead to new methods of treatment. The means by which the microbiome might differ across neuropsychiatric and neurological disorders are not known. Brain disorders as diverse as schizophrenia, major depression, Parkinson's disease and multiple sclerosis appear to share a common pathology of an imbalanced community of commensal microbiota, often measured in terms of a leaky gut phenotype accompanied by low level systemic inflammation. While environmental factors associated with these disease states might contribute to intestinal pathologies, products from a perturbed microbiome may also directly promote specific signs, symptoms and etiologies of individual disorders. We hypothesize that in schizophrenia, it is the putatively unique susceptibility related to genes that modulate the immune system and the gut-brain pleiotropy of these genes which leads to a particularly neuropathological response when challenged by a microbiome in dysbiosis. Consequences from exposure to this dysbiosis may occur during pre- or post-natal time periods and thus may interfere with normal neurodevelopment in those who are genetically predisposed. Here, we review the evidence from the literature which supports the idea that the intersection of the microbiome and immune gene susceptibility in schizophrenia is relevant etiologically and for disease progression. Figuring prominently at both ends of the gut-brain axis and at points in between are proteins encoded by genes found in the major histocompatibility complex (MHC), including select MHC as well as non-MHC complement pathway genes.
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Affiliation(s)
- Emily G Severance
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
| | - Robert H Yolken
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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8
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Nimgaonkar VL, Prasad KM, Chowdari KV, Severance EG, Yolken RH. The complement system: a gateway to gene-environment interactions in schizophrenia pathogenesis. Mol Psychiatry 2017; 22:1554-1561. [PMID: 28761078 PMCID: PMC5656502 DOI: 10.1038/mp.2017.151] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 02/08/2023]
Abstract
The pathogenesis of schizophrenia is considered to be multi-factorial, with likely gene-environment interactions (GEI). Genetic and environmental risk factors are being identified with increasing frequency, yet their very number vastly increases the scope of possible GEI, making it difficult to identify them with certainty. Accumulating evidence suggests a dysregulated complement pathway among the pathogenic processes of schizophrenia. The complement pathway mediates innate and acquired immunity, and its activation drives the removal of damaged cells, autoantigens and environmentally derived antigens. Abnormalities in complement functions occur in many infectious and autoimmune disorders that have been linked to schizophrenia. Many older reports indicate altered serum complement activity in schizophrenia, though the data are inconclusive. Compellingly, recent genome-wide association studies suggest repeat polymorphisms incorporating the complement 4A (C4A) and 4B (C4B) genes as risk factors for schizophrenia. The C4A/C4B genetic associations have re-ignited interest not only in inflammation-related models for schizophrenia pathogenesis, but also in neurodevelopmental theories, because rodent models indicate a role for complement proteins in synaptic pruning and neurodevelopment. Thus, the complement system could be used as one of the 'staging posts' for a variety of focused studies of schizophrenia pathogenesis. They include GEI studies of the C4A/C4B repeat polymorphisms in relation to inflammation-related or infectious processes, animal model studies and tests of hypotheses linked to autoimmune diseases that can co-segregate with schizophrenia. If they can be replicated, such studies would vastly improve our understanding of pathogenic processes in schizophrenia through GEI analyses and open new avenues for therapy.
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Affiliation(s)
- Vishwajit L. Nimgaonkar
- Department of Psychiatry, University of Pittsburgh, School of Medicine, Pittsburgh, PA
- Department of Human Genetics, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA
| | - Konasale M. Prasad
- Department of Psychiatry, University of Pittsburgh, School of Medicine, Pittsburgh, PA
| | - Kodavali V. Chowdari
- Department of Psychiatry, University of Pittsburgh, School of Medicine, Pittsburgh, PA
| | - Emily G. Severance
- Stanley Division of Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Robert H. Yolken
- Stanley Division of Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Md
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Ayhan Y, McFarland R, Pletnikov MV. Animal models of gene-environment interaction in schizophrenia: A dimensional perspective. Prog Neurobiol 2015; 136:1-27. [PMID: 26510407 DOI: 10.1016/j.pneurobio.2015.10.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 09/07/2015] [Accepted: 10/22/2015] [Indexed: 12/12/2022]
Abstract
Schizophrenia has long been considered as a disorder with multifactorial origins. Recent discoveries have advanced our understanding of the genetic architecture of the disease. However, even with the increase of identified risk variants, heritability estimates suggest an important contribution of non-genetic factors. Various environmental risk factors have been proposed to play a role in the etiopathogenesis of schizophrenia. These include season of birth, maternal infections, obstetric complications, adverse events at early childhood, and drug abuse. Despite the progress in identification of genetic and environmental risk factors, we still have a limited understanding of the mechanisms whereby gene-environment interactions (G × E) operate in schizophrenia and psychoses at large. In this review we provide a critical analysis of current animal models of G × E relevant to psychotic disorders and propose that dimensional perspective will advance our understanding of the complex mechanisms of these disorders.
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Affiliation(s)
- Yavuz Ayhan
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA; Hacettepe University Faculty of Medicine, Department of Psychiatry, Turkey
| | - Ross McFarland
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, USA
| | - Mikhail V Pletnikov
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA; Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, USA; Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, USA; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, USA.
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Cytomegalovirus Antibody Elevation in Bipolar Disorder: Relation to Elevated Mood States. Neural Plast 2015; 2015:939780. [PMID: 26075105 PMCID: PMC4444593 DOI: 10.1155/2015/939780] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/23/2014] [Indexed: 11/18/2022] Open
Abstract
The neurobiology of mood states is complicated by exposure to everyday stressors (e.g., psychosocial, ubiquitous environmental infections like CMV), each fluctuating between latency and reactivation. CMV reactivation induces proinflammatory cytokines (e.g., TNF-α) associated with induction of neurotoxic metabolites and the presence of mood states in bipolar disorder (BD). Whether CMV reactivation is associated with bipolar diagnoses (trait) or specific mood states is unclear. We investigated 139 BD type I and 99 healthy controls to determine if concentrations of IgG antibodies to Herpesviridae (e.g., CMV, HSV-1, and HSV-2) were associated with BD-I diagnosis and specific mood states. We found higher CMV antibody concentration in BD-I than in healthy controls (T234 = 3.1, Puncorr = 0.002; Pcorr = 0.006) but no difference in HSV-1 (P > 0.10) or HSV-2 (P > 0.10). Compared to euthymic BD-I volunteers, CMV IgG was higher in BD-I volunteers with elevated moods (P < 0.03) but not different in depressed moods (P > 0.10). While relationships presented between BD-I diagnosis, mood states, and CMV antibodies are encouraging, they are limited by the study's cross sectional nature. Nevertheless, further testing is warranted to replicate findings and determine whether reactivation of CMV infection exacerbates elevated mood states in BD-I.
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11
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Børglum AD, Demontis D, Grove J, Pallesen J, Hollegaard MV, Pedersen CB, Hedemand A, Mattheisen M, Uitterlinden A, Nyegaard M, Ørntoft T, Wiuf C, Didriksen M, Nordentoft M, Nöthen MM, Rietschel M, Ophoff RA, Cichon S, Yolken RH, Hougaard DM, Mortensen PB, Mors O. Genome-wide study of association and interaction with maternal cytomegalovirus infection suggests new schizophrenia loci. Mol Psychiatry 2014; 19:325-33. [PMID: 23358160 PMCID: PMC3932405 DOI: 10.1038/mp.2013.2] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 11/22/2012] [Accepted: 12/14/2012] [Indexed: 12/13/2022]
Abstract
Genetic and environmental components as well as their interaction contribute to the risk of schizophrenia, making it highly relevant to include environmental factors in genetic studies of schizophrenia. This study comprises genome-wide association (GWA) and follow-up analyses of all individuals born in Denmark since 1981 and diagnosed with schizophrenia as well as controls from the same birth cohort. Furthermore, we present the first genome-wide interaction survey of single nucleotide polymorphisms (SNPs) and maternal cytomegalovirus (CMV) infection. The GWA analysis included 888 cases and 882 controls, and the follow-up investigation of the top GWA results was performed in independent Danish (1396 cases and 1803 controls) and German-Dutch (1169 cases, 3714 controls) samples. The SNPs most strongly associated in the single-marker analysis of the combined Danish samples were rs4757144 in ARNTL (P=3.78 × 10(-6)) and rs8057927 in CDH13 (P=1.39 × 10(-5)). Both genes have previously been linked to schizophrenia or other psychiatric disorders. The strongest associated SNP in the combined analysis, including Danish and German-Dutch samples, was rs12922317 in RUNDC2A (P=9.04 × 10(-7)). A region-based analysis summarizing independent signals in segments of 100 kb identified a new region-based genome-wide significant locus overlapping the gene ZEB1 (P=7.0 × 10(-7)). This signal was replicated in the follow-up analysis (P=2.3 × 10(-2)). Significant interaction with maternal CMV infection was found for rs7902091 (P(SNP × CMV)=7.3 × 10(-7)) in CTNNA3, a gene not previously implicated in schizophrenia, stressing the importance of including environmental factors in genetic studies.
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Affiliation(s)
- A D Børglum
- Department of Biomedicine and Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- Centre for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
| | - D Demontis
- Department of Biomedicine and Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
| | - J Grove
- Department of Biomedicine and Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
- Bioinformatics Research Centre, Aarhus University, Aarhus, Denmark
| | - J Pallesen
- Department of Biomedicine and Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
| | - M V Hollegaard
- Section of Neonatal Screening and Hormones, Statens Serum Institute, Copenhagen, Denmark
| | - C B Pedersen
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
- National Centre for Register-based Research, Aarhus University, Aarhus, Denmark
| | - A Hedemand
- Department of Biomedicine and Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
| | - M Mattheisen
- Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany
- Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA
- Institute for Genomic Mathematics, University of Bonn, Bonn, Germany
| | - GROUP investigators
- Department of Biomedicine and Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- Centre for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
- Bioinformatics Research Centre, Aarhus University, Aarhus, Denmark
- Section of Neonatal Screening and Hormones, Statens Serum Institute, Copenhagen, Denmark
- National Centre for Register-based Research, Aarhus University, Aarhus, Denmark
- Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany
- Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA
- Institute for Genomic Mathematics, University of Bonn, Bonn, Germany
- For a full list of members, see Appendix
- Department of Internal Medicine, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
- Department of Molecular Medicine, Aarhus University Hospital, Skejby, Denmark
- Department of Mathematical Science, University of Copenhagen, Copenhagen, Denmark
- Synaptic transmission, H. Lundbeck A/S, Valby, Denmark
- Psychiatric Centre Copenhagen, Copenhagen University Hospital, Copenhagen, Denmark
- Institute of Human Genetics, University of Bonn, Bonn, Germany
- German Center for Neurodegenerative Disorders (DZNE), Bonn, Germany
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Manheim, Germany
- Department of Medical Genetics and Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
- Institute of Neuroscience and Medicine (INM-1), Research Center Juelich, Juelich, Germany
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A Uitterlinden
- Department of Internal Medicine, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
| | - M Nyegaard
- Department of Biomedicine and Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
| | - T Ørntoft
- Department of Molecular Medicine, Aarhus University Hospital, Skejby, Denmark
| | - C Wiuf
- Bioinformatics Research Centre, Aarhus University, Aarhus, Denmark
- Department of Mathematical Science, University of Copenhagen, Copenhagen, Denmark
| | - M Didriksen
- Synaptic transmission, H. Lundbeck A/S, Valby, Denmark
| | - M Nordentoft
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
- Psychiatric Centre Copenhagen, Copenhagen University Hospital, Copenhagen, Denmark
| | - M M Nöthen
- Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany
- Institute of Human Genetics, University of Bonn, Bonn, Germany
- German Center for Neurodegenerative Disorders (DZNE), Bonn, Germany
| | - M Rietschel
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Manheim, Germany
| | - R A Ophoff
- Department of Medical Genetics and Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - S Cichon
- Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany
- Institute of Human Genetics, University of Bonn, Bonn, Germany
- Institute of Neuroscience and Medicine (INM-1), Research Center Juelich, Juelich, Germany
| | - R H Yolken
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - D M Hougaard
- Section of Neonatal Screening and Hormones, Statens Serum Institute, Copenhagen, Denmark
| | - P B Mortensen
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
- National Centre for Register-based Research, Aarhus University, Aarhus, Denmark
| | - O Mors
- Centre for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Denmark
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Debnath M, Cannon DM, Venkatasubramanian G. Variation in the major histocompatibility complex [MHC] gene family in schizophrenia: associations and functional implications. Prog Neuropsychopharmacol Biol Psychiatry 2013; 42:49-62. [PMID: 22813842 DOI: 10.1016/j.pnpbp.2012.07.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 06/23/2012] [Accepted: 07/09/2012] [Indexed: 02/06/2023]
Abstract
Schizophrenia is a chronic debilitating neuropsychiatric disorder with a complex genetic contribution. Although multiple genetic, immunological and environmental factors are known to contribute to schizophrenia susceptibility, the underlying neurobiological mechanism(s) is yet to be established. The immune system dysfunction theory of schizophrenia is experiencing a period of renewal due to a growth in evidence implicating components of the immune system in brain function and human behavior. Current evidence indicates that certain immune molecules such as Major Histocompatibility Complex (MHC) and cytokines, the key regulators of immunity and inflammation are directly involved in the neurobiological processes related to neurodevelopment, neuronal plasticity, learning, memory and behavior. However, the strongest support in favor of the immune hypothesis has recently emerged from on-going genome wide association studies advocating MHC region variants as major determinants of one's risk for developing schizophrenia. Further identification of the interacting partners and receptors of MHC molecules in the brain and their role in down-stream signaling pathways of neurotransmission have implicated these molecules as potential schizophrenia risk factors. More recently, combined brain imaging and genetic studies have revealed a relationship between genetic variations within the MHC region and neuromorphometric changes during schizophrenia. Furthermore, MHC molecules play a significant role in the immune-infective and neurodevelopmental pathogenetic pathways, currently hypothesized to contribute to the pathophysiology of schizophrenia. Herein, we review the immunological, genetic and expression studies assessing the role of the MHC in conferring risk for developing schizophrenia, we summarize and discuss the possible mechanisms involved, making note of the challenges to, and future directions of, immunogenetic research in schizophrenia.
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Affiliation(s)
- Monojit Debnath
- Department of Human Genetics, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore-560029, India.
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Bamne M, Wood J, Chowdari K, Watson AM, Celik C, Mansour H, Klei L, Gur RC, Bradford LD, Calkins ME, Santos AB, Edwards N, Kwentus J, McEvoy JP, Allen TB, Savage RM, Nasrallah HA, Gur RE, Perry RT, Go RC, Devlin B, Yolken R, Nimgaonkar VL. Evaluation of HLA polymorphisms in relation to schizophrenia risk and infectious exposure. Schizophr Bull 2012; 38:1149-54. [PMID: 22966150 PMCID: PMC3494045 DOI: 10.1093/schbul/sbs087] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Genome-wide association studies (GWAS) implicate single nucleotide polymorphisms (SNPs) on chromosome 6p21.3-22.1, the human leukocyte antigen (HLA) region, as common risk factors for schizophrenia (SZ). Other studies implicate viral and protozoan exposure. Our study tests chromosome 6p SNPs for effects on SZ risk with and without exposure. METHOD GWAS-significant SNPs and ancestry-informative marker SNPs were analyzed among African American patients with SZ (n = 604) and controls (n = 404). Exposure to herpes simplex virus, type 1 (HSV-1), cytomegalovirus (CMV), and Toxoplasma gondii (TOX) was assayed using specific antibody assays. RESULTS Five SNPs were nominally associated with SZ, adjusted for population admixture (P < .05, uncorrected for multiple comparisons). These SNPs were next analyzed in relation to infectious exposure. Multivariate analysis indicated significant association between rs3130297 genotype and HSV-1 exposure; the associated allele was different from the SZ risk allele. CONCLUSIONS We propose a model for the genesis of SZ incorporating genomic variation in the HLA region and neurotropic viral exposure for testing in additional, independent African American samples.
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Affiliation(s)
- Mikhil Bamne
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic,Pittsburgh, PA
| | - Joel Wood
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic,Pittsburgh, PA
| | - Kodavali Chowdari
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic,Pittsburgh, PA
| | - Annie M. Watson
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic,Pittsburgh, PA
| | - Cemil Celik
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, Pittsburgh, PA and Department of Psychiatry, GATA School of Medicine, Etlik-Ankara, Turkey
| | - Hader Mansour
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic,Pittsburgh, PA
| | - Lambertus Klei
- Computational Genetics Program, Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Ruben C. Gur
- Department of Psychiatry, Neuropsychiatry Section, University of Pennsylvania, Philadelphia, PA and Philadelphia Veteran’s Affairs Medical Center, Philadelphia, PA
| | | | - Monica E. Calkins
- Department of Psychiatry, Neuropsychiatry Section, University of Pennsylvania, Philadelphia, PA
| | - Alberto B. Santos
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina,Charleston, SC
| | - Neil Edwards
- Department of Psychiatry, University of Tennessee, College of Medicine, Memphis, TN
| | - Joseph Kwentus
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS
| | - Joseph P. McEvoy
- Duke University Medical Center-John Umstead Hospital, Butler, NC
| | - Trina B. Allen
- Duke University Medical Center-John Umstead Hospital, Butler, NC
| | - Robert M. Savage
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL
| | - Henry A. Nasrallah
- Department of Psychiatry and Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Raquel E. Gur
- Department of Psychiatry, Neuropsychiatry Section, University of Pennsylvania, Philadelphia, PA
| | - Rodney T. Perry
- University of Alabama at Birmingham, Epidemiology and International Health, Birmingham, AL
| | - Rodney C.P. Go
- Department of Epidemiology and International Health, University of Alabama at Birmingham, Birmingham, AL
| | - Bernie Devlin
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, Pittsburgh, PA and Department of Human Genetics, Graduate School of Public Health Pittsburgh, University of Pittsburgh, Pittsburgh, PA
| | - Robert Yolken
- Johns Hopkins University Medical Center, Stanley Division of Developmental Neurovirology, Baltimore, MD
| | - Vishwajit L. Nimgaonkar
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, Pittsburgh, PA and Department of Human Genetics, Graduate School of Public Health Pittsburgh, University of Pittsburgh, Pittsburgh, PA;,To whom correspondence should be addressed; tel: 1-412-246-6353, fax: 1-412-246-6350, e-mail:
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Blomström A, Karlsson H, Wicks S, Yang S, Yolken RH, Dalman C. Maternal antibodies to infectious agents and risk for non-affective psychoses in the offspring--a matched case-control study. Schizophr Res 2012; 140:25-30. [PMID: 22819777 DOI: 10.1016/j.schres.2012.06.035] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 06/14/2012] [Accepted: 06/25/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND An increasing number of studies suggest that certain maternal infections are associated with non-affective psychoses in the offspring. Here we investigated if maternal exposure to Toxoplasma gondii, cytomegalovirus (CMV), herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) prior to delivery was associated with future diagnosis of schizophrenia or other non-affective psychoses in the offspring. METHODS This case-control study included 198 individuals born in Sweden 1975-85, diagnosed with schizophrenia (ICD-10, F20) and other non-affective psychoses (ICD-10, F21-29) as in- or outpatients, and 524 matched controls. Specific immunoglobulin G (IgG) levels in archived neonatal dried blood samples from these individuals were determined by immunoassays. Reference levels were determined by prevalences among pregnant women in Sweden 1975-85. Odds ratios (OR) for schizophrenia and other non-affective psychoses were calculated, considering maternal and gestational factors as covariates. RESULTS Levels of IgG directed at T. gondii corresponding to maternal exposure was associated with subsequent schizophrenia (OR=2.1, 95% CI 1.0-4.5) as were levels of IgG directed at CMV (OR=2.2, 95% CI 1.0-5.1) but not at HSV-1 or -2. There were even stronger associations with higher levels of T. gondii or CMV antibodies. There were no associations between any of the infectious agents and other non-affective psychoses. CONCLUSIONS This study supports findings of maternal exposure to T. gondii and schizophrenia risk in offspring, and extends the risk to also include maternal exposure to CMV. Future studies should confirm the association with CMV exposure and identify mechanisms underlying these associations.
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Affiliation(s)
- Asa Blomström
- Division of Public Health Epidemiology, Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.
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15
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Is DNA methylation responsible for immune system dysfunction in schizophrenia? Med Hypotheses 2011; 77:573-9. [DOI: 10.1016/j.mehy.2011.06.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 06/14/2011] [Accepted: 06/15/2011] [Indexed: 01/17/2023]
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Perron H, Lang A. The human endogenous retrovirus link between genes and environment in multiple sclerosis and in multifactorial diseases associating neuroinflammation. Clin Rev Allergy Immunol 2010; 39:51-61. [PMID: 19697163 DOI: 10.1007/s12016-009-8170-x] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Endogenous retroviruses represent about 8% of the human genome and belong to the superfamily of transposable and retrotransposable genetic elements. Altogether, these mobile genetic elements and their numerous inactivated "junk" sequences represent nearly one half of the human DNA. Nonetheless, a significant part of this "non-conventional" genome has retained potential activity. Epigenetic control is notably involved in silencing most of these genetic elements but certain environmental factors such as viruses are known to dysregulate their expression in susceptible cells. More particularly, embryonal cells with limited gene methylation are most susceptible to uncontrolled activation of these mobile genetic elements by, e.g., viral infections. In particular, certain viruses transactivate promoters from endogenous retroviral family type W (HERV-W). HERV-W RNA was first isolated in circulating viral particles (Multiple Sclerosis-associated RetroViral element, MSRV) that have been associated with the evolution and prognosis of multiple sclerosis. HERV-W elements encode a powerful immunopathogenic envelope protein (ENV) that activates a pro-inflammatory and autoimmune cascade through interaction with Toll-like receptor 4 on immune cells. This ENV protein has repeatedly been detected in MS brain lesions and may be involved in other diseases. Epigenetic factors controlling HERV-W ENV protein expression then reveal critical. This review addresses the gene-environment epigenetic interface of such HERV-W elements and its potential involvement in disease.
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Affiliation(s)
- Hervé Perron
- GeNeuro, 18, Chemin des Aulx, 1228, Plan-Les Ouates, Geneva, Switzerland.
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17
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Mortensen PB, Pedersen CB, Hougaard DM, Nørgaard-Petersen B, Mors O, Børglum AD, Yolken RH. A Danish National Birth Cohort study of maternal HSV-2 antibodies as a risk factor for schizophrenia in their offspring. Schizophr Res 2010; 122:257-63. [PMID: 20598509 DOI: 10.1016/j.schres.2010.06.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 05/26/2010] [Accepted: 06/13/2010] [Indexed: 11/24/2022]
Abstract
BACKGROUND Several studies have implicated early infections, including maternal infection with herpes simplex virus 2 (HSV-2), as an environmental risk factor for schizophrenia. METHODS A case-control study nested within the national Danish birth cohort constituted by the PKU Biobank covering all children born in Denmark since 1981. 602 cases of schizophrenia (ICD-10 F20) were ascertained in the Danish Psychiatric Central Register, covering all in- and out-patient contacts in Denmark, and 602 controls were matched individually on gender, exact date of birth and living in Denmark on the date the case became a case. Incidence rate ratio for schizophrenia was estimated using conditional logistic regression. Main exposure was HSV-2 IgG antibody levels. Confounders and potential interacting factors included family history of mental illness, place of birth and gestational age at time of birth. RESULTS Elevated levels of maternal HSV-2 IgG were associated with schizophrenia risk (IRR 1.56; 95% CI 1.17-2.07, p=0.002). This association was not confounded by a maternal or sibling history of psychiatric illness, place of birth, parental age, gestational age, or immigrant status of the parents. However, adjustment for paternal psychiatric history reduced risk slightly (IRR 1.43; 95% CI 1.06-1.92, p=0.02). CONCLUSIONS The study replicates an association between maternal HSV-2 IgG levels and schizophrenia risk. Since the confounding by familial risk factors is confined to paternal mental illnesses not belonging to the schizophrenia spectrum, we hypothesize that this confounding may be partly due to other risk factors, e.g., other sexually transmitted infections, rather than reflecting variations in genetic liability to develop schizophrenia.
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Affiliation(s)
- Preben B Mortensen
- National Centre for Register-based Research, Faculty of Social Sciences, University of Aarhus, Taasingegade 1, DK-8000 Aarhus C, Denmark.
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Animal models of virus-induced neurobehavioral sequelae: recent advances, methodological issues, and future prospects. Interdiscip Perspect Infect Dis 2010; 2010:380456. [PMID: 20490350 PMCID: PMC2872755 DOI: 10.1155/2010/380456] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2009] [Revised: 11/14/2009] [Accepted: 03/09/2010] [Indexed: 01/18/2023] Open
Abstract
Converging lines of clinical and epidemiological evidence suggest that viral infections in early developmental stages may be a causal factor in neuropsychiatric disorders such as schizophrenia, bipolar disorder, and autism-spectrum disorders. This etiological link, however, remains controversial in view of the lack of consistent and reproducible associations between viruses and mental illness. Animal models of virus-induced neurobehavioral disturbances afford powerful tools to test etiological hypotheses and explore pathophysiological mechanisms. Prenatal or neonatal inoculations of neurotropic agents (such as herpes-, influenza-, and retroviruses) in rodents result in a broad spectrum of long-term alterations reminiscent of psychiatric abnormalities. Nevertheless, the complexity of these sequelae often poses methodological and interpretational challenges and thwarts their characterization. The recent conceptual advancements in psychiatric nosology and behavioral science may help determine new heuristic criteria to enhance the translational value of these models. A particularly critical issue is the identification of intermediate phenotypes, defined as quantifiable factors representing single neurochemical, neuropsychological, or neuroanatomical aspects of a diagnostic category. In this paper, we examine how the employment of these novel concepts may lead to new methodological refinements in the study of virus-induced neurobehavioral sequelae through animal models.
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Prasad KM, Bamne MN, Shirts BH, Goradia D, Mannali V, Pancholi KM, Xue B, McClain L, Yolken RH, Keshavan MS, Nimgaonkar VL. Grey matter changes associated with host genetic variation and exposure to Herpes Simplex Virus 1 (HSV1) in first episode schizophrenia. Schizophr Res 2010; 118:232-9. [PMID: 20138739 PMCID: PMC2856756 DOI: 10.1016/j.schres.2010.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 12/31/2009] [Accepted: 01/04/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND We previously reported reduced prefrontal cortex (PFC) grey matter volume among first episode, antipsychotic-naïve schizophrenia subjects (SZ) exposed to HSV1 but not among healthy subjects (HS) (Prasad et al., 2007). Independently, rs1051788, an exonic polymorphism of the MHC Class I polypeptide-related sequence B (MICB) gene was associated with HSV1 seropositivity, as well as SZ risk. In this study, we examined whether PFC grey matter changes associated with HSV1 exposure varied against the background of MICB genotypes. METHODS We examined Caucasian individuals from the sample we studied in our previous report (Prasad et al., 2007) (SZ, n=21 and HS, n=19). Whole brain voxelwise analysis of structural MRI scans was conducted using Statistical Parametric Mapping, ver 5 (SPM5). The impact of rs1051788 variation and HSV1 seropositivity on grey matter volumes was examined using regression models on the combined sample of cases and controls, and then within each diagnostic group. RESULTS In the combined sample of cases and controls, we observed the main effects of HSV1 seropositivity and genotypes, and a significant joint effect of HSV1 seropositivity and genotype mainly in the PFC. The joint effect was more prominent among cases than among controls. DISCUSSION Our observations suggest that rs1051788 and HSV1 seropositivity are associated individually and jointly with reduced PFC grey matter volume. The patterns of these associations differ by diagnostic status, and these factors explain only a "small" portion of the variance in the grey matter volume reductions.
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Affiliation(s)
- Konasale M Prasad
- University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States.
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Candidate genes and their interactions with other genetic/environmental risk factors in the etiology of schizophrenia. Brain Res Bull 2009; 83:86-92. [PMID: 19729054 DOI: 10.1016/j.brainresbull.2009.08.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 08/04/2009] [Accepted: 08/25/2009] [Indexed: 11/21/2022]
Abstract
Identification of causative factors for common, chronic disorders is a major focus of current human health science research. These disorders are likely to be caused by multiple etiological agents. Available evidence also suggests that interactions between the risk factors may explain some of their pathogenic effects. While progress in genomics and allied biological research has brought forth powerful analytic techniques, the predicted complexity poses daunting analytic challenges. The search for pathogenesis of schizophrenia shares most of these challenges. We have reviewed the analytic and logistic problems associated with the search for pathogenesis. Evidence for pathogenic interactions is presented for selected diseases and for schizophrenia. We end by suggesting 'recursive analyses' as a potential design to address these challenges. This scheme involves initial focused searches for interactions motivated by available evidence, typically involving identified individual risk factors, such as candidate gene variants. Putative interactions are tested rigorously for replication and for biological plausibility. Support for the interactions from statistical and functional analyses motivates a progressively larger array of interactants that are evaluated recursively. The risk explained by the interactions is assessed concurrently and further elaborate searches may be guided by the results of such analyses. By way of example, we summarize our ongoing analyses of dopaminergic polymorphisms, as well as infectious etiological factors in schizophrenia genesis.
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Olgiati P, Mandelli L, Lorenzi C, Marino E, Adele P, Ferrari B, De Ronchi D, Serretti A. Schizophrenia: genetics, prevention and rehabilitation. Acta Neuropsychiatr 2009; 21:109-20. [PMID: 26953749 DOI: 10.1111/j.1601-5215.2009.00360.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Genetic factors are largely implicated in predisposing to schizophrenia. Environmental factors contribute to the onset of the disorder in individuals at increased genetic risk. Cognitive deficits have emerged as endophenotypes and potential therapeutic targets for schizophrenia because of their association with functional outcome. The aims of this review were to analyse the joint effect of genetic and environmental (G×E) factors on liability to schizophrenia and to investigate relationships between genes and cognitive endophenotypes focusing on practical applications for prevention and rehabilitation. METHODS Medline search of relevant studies published between 1990 and 2008. RESULTS In schizophrenia, examples of G×E interaction include the catechol-O-methyl transferase (COMT) (Val158Met) polymorphism, which was found to moderate the onset of psychotic manifestations in response to stress and to increase the risk for psychosis related to cannabis use, and neurodevelopmental genes such as AKT1 (serine-threonine kinase), brain-derived neurotrophic factor (BDNF), DTNBP1 (dysbindin) and GRM3 (metabotropic glutamate receptor 3), which were associated with development of schizophrenia in adulthood after exposure to perinatal obstetric complications. Neurocognitive deficits are recognised as core features of schizophrenia that facilitate the onset of the disorder and have a great impact on functional outcome. Neurocognitive deficits are also endophenotypes that have been linked to a variety of genes [COMT, neuregulin (NRG1), BDNF, Disrupted-In-Schizophrenia 1 (DISC1) and dysbindin] conferring susceptibility to schizophrenia. Recently, it has emerged that cognitive improvement during rehabilitation therapy was under control of COMT (Val158Met) polymorphism. CONCLUSION This review could indicate a pivotal role of psychiatric genetics in prevention and rehabilitation of schizophrenic psychoses.
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Affiliation(s)
- Paolo Olgiati
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Laura Mandelli
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Cristina Lorenzi
- 2Department of Psychiatry, Istituto Scientifico San Raffaele, Vita-Salute University, Milan, Italy
| | - Elena Marino
- 2Department of Psychiatry, Istituto Scientifico San Raffaele, Vita-Salute University, Milan, Italy
| | - Pirovano Adele
- 2Department of Psychiatry, Istituto Scientifico San Raffaele, Vita-Salute University, Milan, Italy
| | - Barbara Ferrari
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Diana De Ronchi
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
| | - Alessandro Serretti
- 1Department of Psychiatry, Institute of Psychiatry, Bologna University, Italy
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Perron H, Mekaoui L, Bernard C, Veas F, Stefas I, Leboyer M. Endogenous retrovirus type W GAG and envelope protein antigenemia in serum of schizophrenic patients. Biol Psychiatry 2008; 64:1019-23. [PMID: 18760403 DOI: 10.1016/j.biopsych.2008.06.028] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 06/23/2008] [Accepted: 06/29/2008] [Indexed: 02/06/2023]
Abstract
BACKGROUND Recent and independent molecular studies have shown an association between human endogenous retroviruses type "W" family (HERV-W) and schizophrenia, mostly by polymerase chain reaction studies, but none has yet addressed specific antigen detection in living patients. METHODS Forty-nine schizophrenic patients and an equivalent number of healthy control subjects were included in the present exploratory study. The HERV-W GAG and envelope (ENV) proteins were quantified in the serum with a dedicated immunoassay set-up with specific monoclonal antibodies to either antigen. RESULTS In schizophrenic patients, positive antigenemia for ENV was found in 23 of 49 (47%) and for GAG in 24 of 49 (49%). Only 1 of 30 (3%) for ENV and 2 of 49 (4%) for GAG were positive in blood donors (p < .01 for ENV; p < .001 for GAG). Interestingly, bioclinical data analyses revealed significant correlation between GAG or ENV antigenemia (a protein causing dysimmune inflammatory effects) and C-reactive protein (CRP) levels (a systemic inflammation biomarker). CONCLUSIONS Frequently elevated CRP has previously been described in schizophrenic patients and has been shown to match with an evolution toward cognitive deficit and neuronal loss. Elsewhere viruses such as influenza, long-associated with risk for schizophrenia through perinatal infections, have been shown to activate HERV-W elements in human cells. We therefore discuss a relationship between environment factors long-associated with early risk, genetic factors represented by this endogenous family, the production of its pro-inflammatory ENV protein and known "inflammation-mediated" neurotoxicity, as a possible hypothesis for a pathogenic cascade in association with HERV-W. Our present results thus confirm that HERV-W studies have opened a novel avenue of research in schizophrenia.
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Shirts BH, Kim JJ, Reich S, Dickerson FB, Yolken RH, Devlin B, Nimgaonkar VL. Polymorphisms in MICB are associated with human herpes virus seropositivity and schizophrenia risk. Schizophr Res 2007; 94:342-53. [PMID: 17561376 DOI: 10.1016/j.schres.2007.04.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 12/22/2006] [Accepted: 04/24/2007] [Indexed: 01/29/2023]
Abstract
Viral infection may be a risk factor for schizophrenia and has been associated with decreased cognitive functioning in patients. We report associations of SNPs at MICB (MHC class I polypeptide-related sequence B, chromosome 6p21) with cytomegalovirus and herpes simplex virus 1 seropositivity. We previously found associations with schizophrenia on chromosome 6p21 among patients seropositive for cytomegalovirus (CMV) and herpes simplex virus 1 (HSV1). To localize the associations further, we genotyped 26 SNPs spanning 100 kb in a sample of 236 Caucasian schizophrenia patients and 240 controls. Based on suggestive associations, we selected five SNPs at MICB to assay among two additional Caucasian samples that had been serotyped for CMV and HSV1: a case-control sample recruited in Baltimore (n=272 cases, 108 controls), and a case-parent trio sample recruited in Pittsburgh (n=221). Among Baltimore control individuals there were significant associations with antibody status for infectious agents: rs1051788 with HSV1 seropositivity (p=0.006) and rs2523651 with cytomegalovirus seropositivity (p=0.001). The former association was also detectable among the parents of cases recruited in Pittsburgh (p=0.024). Neither viral association was noted among the schizophrenia cases. With respect to schizophrenia risk, significant transmission distortion was noted at rs1051788 and rs1055569 among the case-parent trios regardless of antibody status (p=0.014 and 0.036 respectively). A similar trend for association with schizophrenia liability at rs1051788 in the Baltimore sample did not attain statistical significance. There are a number of explanations for the associations, including chance variation, as well as gene-virus interactions. Further replicate studies are warranted, as are functional studies of these polymorphisms.
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Affiliation(s)
- Brian H Shirts
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, 3811 O'Hara Street, Pittsburgh, Pennsylvania 15213, USA
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