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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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Uezato A, Jitoku D, Shimazu D, Yamamoto N, Kurumaji A, Iwayama Y, Toyota T, Yoshikawa T, Haroutunian V, Bentea E, Meller J, Sullivan CR, Meador-Woodruff JH, McCullumsmith RE, Nishikawa T. Differential genetic associations and expression of PAPST1/SLC35B2 in bipolar disorder and schizophrenia. J Neural Transm (Vienna) 2022; 129:913-924. [PMID: 35501530 DOI: 10.1007/s00702-022-02503-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 04/12/2022] [Indexed: 11/27/2022]
Abstract
Lithium's inhibitory effect on enzymes involved in sulfation process, such as inhibition of 3'(2')-phosphoadenosine 5'-phosphate (PAP) phosphatase, is a possible mechanism of its therapeutic effect for bipolar disorder (BD). 3'-Phosphoadenosine 5'-phosphosulfate (PAPS) is translocated from cytosol to Golgi lumen by PAPS transporter 1 (PAPST1/SLC35B2), where it acts as a sulfa donor. Since SLC35B2 was previously recognized as a molecule that facilitates the release of D-serine, a co-agonist of N-methyl-D-aspartate type glutamate receptor, altered function of SLC35B2 might be associated with the pathophysiology of BD and schizophrenia (SCZ). We performed genetic association analyses of the SLC35B2 gene using Japanese cohorts with 366 BD cases and 370 controls and 2012 SCZ cases and 2170 controls. We then investigated expression of SLC35B2 mRNA in postmortem brains by QPCR using a Caucasian cohort with 33 BD and 34 SCZ cases and 34 controls and by in situ hybridization using a Caucasian cohort with 37 SCZ and 29 controls. We found significant associations between three SNPs (rs575034, rs1875324, and rs3832441) and BD, and significantly reduced SLC35B2 mRNA expression in postmortem dorsolateral prefrontal cortex (DLPFC) of BD. Moreover, we observed normalized SLC35B2 mRNA expression in BD subgroups who were medicated with lithium. While there was a significant association of SLC35B2 with SCZ (SNP rs2233437), its expression was not changed in SCZ. These findings indicate that SLC35B2 might be differentially involved in the pathophysiology of BD and SCZ by influencing the sulfation process and/or glutamate system in the central nervous system.
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Affiliation(s)
- Akihito Uezato
- School of Health and Welfare, International University of Health and Welfare, Tochigi, Japan
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Daisuke Jitoku
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Dai Shimazu
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
- Musashishinjo-Kokorono Clinic, Kanagawa, Japan
| | - Naoki Yamamoto
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
- Center for Basic Medical Research, and School of Pharmaceutical Sciences, International University of Health and Welfare, Tochigi, Japan
| | - Akeo Kurumaji
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
- Shimousa-Nakayama Mental Clinic, Chiba, Japan
| | - Yoshimi Iwayama
- Laboratory for Molecular Psychiatry, RIKEN Center for Brain Science, Saitama, Japan
- Laboratory for Bioinformatics Research, RIKEN Center for Biosystems Dynamics Research, Hyogo, Japan
| | - Tomoko Toyota
- Laboratory for Molecular Psychiatry, RIKEN Center for Brain Science, Saitama, Japan
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, Saitama, Japan
| | - Takeo Yoshikawa
- Laboratory for Molecular Psychiatry, RIKEN Center for Brain Science, Saitama, Japan
- Office of the Center Director, RIKEN Center for Brain Science, Saitama, Japan
| | - Vahram Haroutunian
- Department of Psychiatry and Neuroscience, The Icahn School of Medicine at Mount Sinai, Bronx, NY, USA
| | - Eduard Bentea
- Neurosciences TA Biology, UCB BioPharma SPRL, Braine-l'Alleud, Belgium
| | - Jarek Meller
- Departments of Environmental Health, Electrical Engineering and Computing Systems and Biomedical Informatics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | - James H Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Alabama, USA
| | - Robert E McCullumsmith
- Department of Neuroscience, University of Toledo, Toledo, OH, USA
- Promedica, Toledo, OH, USA
| | - Toru Nishikawa
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
- Department of Pharmacology, Faculty of Medicine, and Pharmacological Research Center, Showa University, 1-5-8, Shinagawa-ku, Tokyo, 142-8555, Japan.
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Transcriptomic and Proteomic Analysis of CRISPR/Cas9-Mediated ARC-Knockout HEK293 Cells. Int J Mol Sci 2022; 23:ijms23094498. [PMID: 35562887 PMCID: PMC9101110 DOI: 10.3390/ijms23094498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/15/2022] [Accepted: 04/17/2022] [Indexed: 02/04/2023] Open
Abstract
Arc/Arg3.1 (activity-regulated cytoskeletal-associated protein (ARC)) is a critical regulator of long-term synaptic plasticity and is involved in the pathophysiology of schizophrenia. The functions and mechanisms of human ARC action are poorly understood and worthy of further investigation. To investigate the function of the ARC gene in vitro, we generated an ARC-knockout (KO) HEK293 cell line via CRISPR/Cas9-mediated gene editing and conducted RNA sequencing and label-free LC-MS/MS analysis to identify the differentially expressed genes and proteins in isogenic ARC-KO HEK293 cells. Furthermore, we used bioluminescence resonance energy transfer (BRET) assays to detect interactions between the ARC protein and differentially expressed proteins. Genetic deletion of ARC disturbed multiple genes involved in the extracellular matrix and synaptic membrane. Seven proteins (HSPA1A, ENO1, VCP, HMGCS1, ALDH1B1, FSCN1, and HINT2) were found to be differentially expressed between ARC-KO cells and ARC wild-type cells. BRET assay results showed that ARC interacted with PSD95 and HSPA1A. Overall, we found that ARC regulates the differential expression of genes involved in the extracellular matrix, synaptic membrane, and heat shock protein family. The transcriptomic and proteomic profiles of ARC-KO HEK293 cells presented here provide new evidence for the mechanisms underlying the effects of ARC and molecular pathways involved in schizophrenia pathophysiology.
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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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Identification of ultra-rare missense mutations associated with familial schizophrenia by whole-exome sequencing. Schizophr Res 2021; 235:60-62. [PMID: 34325211 DOI: 10.1016/j.schres.2021.07.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/14/2021] [Accepted: 07/19/2021] [Indexed: 11/21/2022]
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Abstract
The notion of immunological pathways playing a role in the etiology of a subset of psychotic disorders has received increased interest in the last decades. One of the findings that has spiked interest herein, is an apparent link between autoimmune diseases and psychotic disorders. This is supported by genetic findings associating immune-related genetic markers with schizophrenia and clinical studies finding increased levels of inflammatory markers in patients with psychosis. Several large-scale epidemiologic studies have found positive associations between autoimmune diseases and psychosis. Particularly, autoimmune diseases as multiple sclerosis and lupus are known to have higher frequencies of neuropsychiatric symptoms, including psychosis, compared to healthy controls. Cross sectional studies have found higher prevalence of psychiatric diagnoses among those with autoimmune diseases, and longitudinal studies have shown bidirectional associations between several autoimmune diseases and increased risks associated with schizophrenia. Moreover, a family history of autoimmune diseases has been shown to be associated with an increased risk of psychotic disorders and vice versa. In this review we will summarize the epidemiologic evidence on associations between autoimmune diseases and psychosis. Possible mechanisms accountable for the association will be discussed, amongst others the probable role of shared genetic risk factors, the impact of infections on both autoimmunity and the development of psychotic disorders, and the potential role of the microbiome. We discuss the findings on and influence of autoantibodies and dysregulation of T- and B-cells in both disease categories, and why further research hereon is needed. In addition to the potential importance of autoimmunity in etiological mechanisms of psychotic disorders, the association also brings important attention to somatic comorbidity in patients with psychotic disorders.
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Affiliation(s)
- Rose Jeppesen
- Mental Health Centre Copenhagen, Gentofte Hospital, Copenhagen University Hospital, Hellerup, Denmark
| | - Michael Eriksen Benros
- Mental Health Centre Copenhagen, Gentofte Hospital, Copenhagen University Hospital, Hellerup, Denmark
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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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Felger JC. Imaging the Role of Inflammation in Mood and Anxiety-related Disorders. Curr Neuropharmacol 2018; 16:533-558. [PMID: 29173175 PMCID: PMC5997866 DOI: 10.2174/1570159x15666171123201142] [Citation(s) in RCA: 244] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/23/2017] [Accepted: 11/21/2017] [Indexed: 02/08/2023] Open
Abstract
Background Studies investigating the impact of a variety of inflammatory stimuli on the brain and behavior have reported evidence that inflammation and release of inflammatory cytokines affect circuitry relevant to both reward and threat sensitivity to contribute to behavioral change. Of relevance to mood and anxiety-related disorders, biomarkers of inflammation such as inflammatory cytokines and acute-phase proteins are reliably elevated in a significant proportion of patients with major depressive disorder (MDD), bipolar disorder, anxiety disorders and post-traumatic stress disorder (PTSD). Methods This review summarized clinical and translational work demonstrating the impact of peripheral inflammation on brain regions and neurotransmitter systems relevant to both reward and threat sensitivity, with a focus on neuroimaging studies involving administration of inflammatory stimuli. Recent translation of these findings to further understand the role of inflammation in mood and anxiety-related disorders is also discussed. Results Inflammation was consistently found to affect basal ganglia and cortical reward and motor circuits to drive reduced motivation and motor activity, as well as anxiety-related brain regions including amygdala, insula and anterior cingulate cortex, which may result from cytokine effects on monoamines and glutamate. Similar relationships between inflammation and altered neurocircuitry have been observed in MDD patients with increased peripheral inflammatory markers, and such work is on the horizon for anxiety disorders and PTSD. Conclusion Neuroimaging effects of inflammation on reward and threat circuitry may be used as biomarkers of inflammation for future development of novel therapeutic strategies to better treat mood and anxiety-related disorders in patients with high inflammation.
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Affiliation(s)
- Jennifer C Felger
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States.,Winship Cancer Institute, Emory University, Atlanta, GA, United States
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Al‐Diwani AAJ, Pollak TA, Irani SR, Lennox BR. Psychosis: an autoimmune disease? Immunology 2017; 152:388-401. [PMID: 28704576 PMCID: PMC5629440 DOI: 10.1111/imm.12795] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/03/2017] [Accepted: 07/05/2017] [Indexed: 12/22/2022] Open
Abstract
Psychotic disorders are common and disabling. Overlaps in clinical course in addition to epidemiological and genetic associations raise the possibility that autoimmune mechanisms may underlie some psychoses, potentially offering novel therapeutic approaches. Several immune loci including the major histocompatibility complex and B-cell markers CD19 and CD20 achieve genome-wide significance in schizophrenia. Emerging evidence suggests a potential role via neurodevelopment in addition to classical immune pathways. Additionally, lymphocyte biology is increasingly investigated. Some reports note raised peripheral CD19+ and reduced CD3+ lymphocyte counts, with altered CD4 : CD8 ratios in acute psychosis. Also, post-mortem studies have found CD3+ and CD20+ lymphocyte infiltration in brain regions that are of functional relevance to psychosis. More specifically, the recent paradigm of neuronal surface antibody-mediated (NSAb) central nervous system disease provides an antigen-specific model linking adaptive autoimmunity to psychopathology. NSAbs bind extracellular epitopes of signalling molecules that are classically implicated in psychosis such as NMDA and GABA receptors. This interaction may cause circuit dysfunction leading to psychosis among other neurological features in patients with autoimmune encephalitis. The detection of these cases is crucial as autoimmune encephalitis is ameliorated by commonly available immunotherapies. Meanwhile, the prevalence and relevance of these antibodies in people with isolated psychotic disorders is an area of emerging scientific and clinical interest. Collaborative efforts to achieve larger sample sizes, comparison of assay platforms, and placebo-controlled randomized clinical trials are now needed to establish an autoimmune contribution to psychosis.
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Affiliation(s)
- Adam A. J. Al‐Diwani
- Department of PsychiatryWarneford HospitalUniversity of OxfordOxfordUK
- Autoimmune Neurology GroupNuffield Department of Clinical NeurosciencesJohn Radcliffe HospitalUniversity of OxfordOxfordUK
| | - Thomas A. Pollak
- Department of Psychosis StudiesInstitute of Psychiatry, Psychology and NeuroscienceKing's Health PartnersLondonUK
| | - Sarosh R. Irani
- Autoimmune Neurology GroupNuffield Department of Clinical NeurosciencesJohn Radcliffe HospitalUniversity of OxfordOxfordUK
| | - Belinda R. Lennox
- Department of PsychiatryWarneford HospitalUniversity of OxfordOxfordUK
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Attempts to replicate genetic associations with schizophrenia in a cohort from north India. NPJ SCHIZOPHRENIA 2017; 3:28. [PMID: 28855605 PMCID: PMC5577284 DOI: 10.1038/s41537-017-0030-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/18/2017] [Accepted: 07/24/2017] [Indexed: 12/22/2022]
Abstract
Schizophrenia is a chronic, severe, heritable disorder. Genome-wide association studies, conducted predominantly among Caucasians, have indicated > 100 risk alleles, with most significant SNPs on chromosome 6. There is growing interest as to whether these risk alleles are relevant in other ethnic groups as well. Neither an Indian genome-wide association studies nor a systematic replication of GWAS findings from other populations are reported. Thus, we analyzed 32 SNPs, including those associated in the Caucasian ancestry GWAS and other candidate gene studies, in a north Indian schizophrenia cohort (n = 1009 patients; n = 1029 controls) using a Sequenom mass array. Cognitive functioning was also assessed using the Hindi version of the Penn Computerized Neuropsychological Battery in a subset of the sample. MICB (rs6916394) a previously noted Caucasian candidate, was associated with schizophrenia at the p = 0.02 level. One SNP, rs2064430, AHI1 (6q23.3, SZ Gene database SNP) was associated at the p = 0.04 level. Other candidates had even less significance with rs6932590, intergenic (p = 0.07); rs3130615, MICB (p = 0.08); rs6916921, NFKBIL1 (p = 0.08) and rs9273012, HLA-DQA1 (p = 0.06) and haplotypic associations (p = 0.01-0.05) of 6p SNPs were detected. Of note, nominally significant associations with cognitive variables were identified, after covarying for age and diagnostic status. SNPs with p < 0.01 were: rs3130375, with working memory (p = 0.007); rs377763, with sensorimotor (p = 0.004); rs6916921, NFKBIL1 with emotion (p = 0.01). This relative lack of significant positive associations is likely influenced by the sample size and/or differences in the genetic architecture of schizophrenia across populations, encouraging population specific studies to identify shared and unique genetic risk factors for schizophrenia. POPULATION GENETICS CAUCASIANS AND INDIANS EXHIBIT GENETIC DISJUNCTION IN SCHIZOPHRENIA: A tenuous link between schizophrenia's genetic basis in Caucasians and Indians calls for more comprehensive research on the latter. Large-scale analyses of the human genome have identified over a hundred genetic variations associated with schizophrenia; however, these have focused largely on European and North American populations. Researchers led by the University of Delhi's BK Thelma, and Smita Deshpande of the Dr. Ram Manohar Lohia Hospital, India, selected 32 gene variations from past studies to look for similar associations in Indians. Many assays met limited success, though the team found significant correlations between certain variations and specific cognitive hallmarks of schizophrenia. Aside from differences in genetic architecture, the lack of adequate and comparable genetic data on schizophrenia in Indians may contribute to this apparent difference to schizophrenia in Caucasian patients. This shows a clear need for more schizophrenia genetic studies in India.
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Del Grande C, Galli L, Schiavi E, Dell'Osso L, Bruschi F. Is Toxoplasma gondii a Trigger of Bipolar Disorder? Pathogens 2017; 6:pathogens6010003. [PMID: 28075410 PMCID: PMC5371891 DOI: 10.3390/pathogens6010003] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/16/2016] [Accepted: 01/04/2017] [Indexed: 11/16/2022] Open
Abstract
Toxoplasma gondii, a ubiquitous intracellular parasite, has a strong tropism for the brain tissue, where it forms intracellular cysts within the neurons and glial cells, establishing a chronic infection. Although latent toxoplasmosis is generally assumed to be asymptomatic in immunocompetent individuals, it is now clear that it can induce behavioral manipulations in mice and infected humans. Moreover, a strong relation has emerged in recent years between toxoplasmosis and psychiatric disorders. The link between T. gondii and schizophrenia has been the most widely documented; however, a significant association with bipolar disorder (BD) and suicidal/aggressive behaviors has also been detected. T. gondii may play a role in the etiopathogenesis of psychiatric disorders affecting neurotransmitters, especially dopamine, that are implicated in the emergence of psychosis and behavioral Toxoplasma-induced abnormalities, and inducing brain inflammation by the direct stimulation of inflammatory cytokines in the central nervous system. Besides this, there is increasing evidence for a prominent role of immune dysregulation in psychosis and BD. The aim of this review is to describe recent evidence suggesting a link between Toxoplasma gondii and BD, focusing on the interaction between immune responses and this infectious agent in the etiopathogenesis of psychiatric symptoms.
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Affiliation(s)
- Claudia Del Grande
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa, Via Roma 67, 56127 Pisa, Italy.
| | - Luca Galli
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
| | - Elisa Schiavi
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa, Via Roma 67, 56127 Pisa, Italy.
| | - Liliana Dell'Osso
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa, Via Roma 67, 56127 Pisa, Italy.
| | - Fabrizio Bruschi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
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Felger JC, Treadway MT. Inflammation Effects on Motivation and Motor Activity: Role of Dopamine. Neuropsychopharmacology 2017; 42:216-241. [PMID: 27480574 PMCID: PMC5143486 DOI: 10.1038/npp.2016.143] [Citation(s) in RCA: 244] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 07/13/2016] [Accepted: 07/27/2016] [Indexed: 01/18/2023]
Abstract
Motivational and motor deficits are common in patients with depression and other psychiatric disorders, and are related to symptoms of anhedonia and motor retardation. These deficits in motivation and motor function are associated with alterations in corticostriatal neurocircuitry, which may reflect abnormalities in mesolimbic and mesostriatal dopamine (DA). One pathophysiologic pathway that may drive changes in DAergic corticostriatal circuitry is inflammation. Biomarkers of inflammation such as inflammatory cytokines and acute-phase proteins are reliably elevated in a significant proportion of psychiatric patients. A variety of inflammatory stimuli have been found to preferentially target basal ganglia function to lead to impaired motivation and motor activity. Findings have included inflammation-associated reductions in ventral striatal neural responses to reward anticipation, decreased DA and DA metabolites in cerebrospinal fluid, and decreased availability, and release of striatal DA, all of which correlated with symptoms of reduced motivation and/or motor retardation. Importantly, inflammation-associated symptoms are often difficult to treat, and evidence suggests that inflammation may decrease DA synthesis and availability, thus circumventing the efficacy of standard pharmacotherapies. This review will highlight the impact of administration of inflammatory stimuli on the brain in relation to motivation and motor function. Recent data demonstrating similar relationships between increased inflammation and altered DAergic corticostriatal circuitry and behavior in patients with major depressive disorder will also be presented. Finally, we will discuss the mechanisms by which inflammation affects DA neurotransmission and relevance to novel therapeutic strategies to treat reduced motivation and motor symptoms in patients with high inflammation.
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Affiliation(s)
- Jennifer C Felger
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
- Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Michael T Treadway
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
- Winship Cancer Institute, Emory University, Atlanta, GA, USA
- Department of Psychology, Emory University, Atlanta, GA, USA
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HLA Class I and II alleles, heterozygosity and HLA-KIR interactions are associated with rates of genital HSV shedding and lesions. Genes Immun 2016; 17:412-418. [PMID: 27853144 PMCID: PMC5133162 DOI: 10.1038/gene.2016.42] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 10/10/2016] [Accepted: 10/17/2016] [Indexed: 01/02/2023]
Abstract
Variation at HLA and KIR loci is associated with the severity of viral infections. To assess associations of genital HSV-2 infection with human HLA and KIR genetic loci, we measured the frequencies of genital HSV DNA detection and of genital lesions in HSV-2 seropositive persons. We followed 267 HSV-2 seropositive persons who collected daily genital swabs and recorded lesions for ≥30 days. All persons were laboratory- documented as HIV-seronegative, and all were Caucasian by self-report. HSV detection rate and lesion frequency were compared by genotype using Poisson regression. Overall, HSV was detected on 19.1% of days and lesions on 11.6% of days. The presence of HLA-A*01 was directly associated with HSV detection frequency while the presence of HLA-C*12 was inversely associated with HSV detection frequency. The presence of HLA-A*01 was directly associated with lesion rate, while HLA-A*26, -C*01 and -DQB1*0106 were associated with decreased lesions. We observed an interaction between the absence of both 2DS4del and HLA-Bw4 and higher lesion rate. Heterozygosity of HLA was also associated with reduced lesion frequency. Immune control of genital HSV infection relies on multiple interacting immunogenetic elements, including epistatic interactions between HLA and KIR.
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Trépanier MO, Hopperton KE, Mizrahi R, Mechawar N, Bazinet RP. Postmortem evidence of cerebral inflammation in schizophrenia: a systematic review. Mol Psychiatry 2016; 21:1009-26. [PMID: 27271499 PMCID: PMC4960446 DOI: 10.1038/mp.2016.90] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/29/2016] [Accepted: 04/20/2016] [Indexed: 12/13/2022]
Abstract
Schizophrenia is a psychiatric disorder which has a lifetime prevalence of ~1%. Multiple candidate mechanisms have been proposed in the pathogenesis of schizophrenia. One such mechanism is the involvement of neuroinflammation. Clinical studies, including neuroimaging, peripheral biomarkers and randomized control trials, have suggested the presence of neuroinflammation in schizophrenia. Many studies have also measured markers of neuroinflammation in postmortem brain samples from schizophrenia patients. The objective of this study was to conduct a systematic search of the literature on neuroinflammation in postmortem brains of schizophrenia patients indexed in MEDLINE, Embase and PsycINFO. Databases were searched up until 20th March 2016 for articles published on postmortem brains in schizophrenia evaluating microglia, astrocytes, glia, cytokines, the arachidonic cascade, substance P and other markers of neuroinflammation. Two independent reviewers extracted the data. Out of 5385 articles yielded by the search, 119 articles were identified that measured neuroinflammatory markers in schizophrenic postmortem brains. Glial fibrillary acidic protein expression was elevated, lower or unchanged in 6, 6 and 21 studies, respectively, and similar results were obtained for glial cell densities. On the other hand, microglial markers were increased, lower or unchanged in schizophrenia in 11, 3 and 8 studies, respectively. Results were variable across all other markers, but SERPINA3 and IFITM were consistently increased in 4 and 5 studies, respectively. Despite the variability, some studies evaluating neuroinflammation in postmortem brains in schizophrenia suggest an increase in microglial activity and other markers such as SERPINA3 and IFITM. Variability across studies is partially explained by multiple factors including brain region evaluated, source of the brain, diagnosis, age at time of death, age of onset and the presence of suicide victims in the cohort.
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Affiliation(s)
- M O Trépanier
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - K E Hopperton
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - R Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - N Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Montreal, QC, Canada
- Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - R P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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16
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Sutterland AL, Fond G, Kuin A, Koeter MWJ, Lutter R, van Gool T, Yolken R, Szoke A, Leboyer M, de Haan L. Beyond the association. Toxoplasma gondii in schizophrenia, bipolar disorder, and addiction: systematic review and meta-analysis. Acta Psychiatr Scand 2015; 132:161-79. [PMID: 25877655 DOI: 10.1111/acps.12423] [Citation(s) in RCA: 286] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/17/2015] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To perform a meta-analysis on studies reporting prevalence of Toxoplasma gondii (T. gondii) infection in any psychiatric disorder compared with healthy controls. Our secondary objective was to analyze factors possibly moderating heterogeneity. METHOD A systematic search was performed to identify studies into T. gondii infection for all major psychiatric disorders versus healthy controls. Methodological quality, publication bias, and possible moderators were assessed. RESULTS A total of 2866 citations were retrieved and 50 studies finally included. Significant odds ratios (ORs) with IgG antibodies were found in schizophrenia (OR 1.81, P < 0.00001), bipolar disorder (OR 1.52, P = 0.02), obsessive-compulsive disorder (OR 3.4, P < 0.001), and addiction (OR 1.91, P < 0.00001), but not for major depression (OR 1.21, P = 0.28). Exploration of the association between T. gondii and schizophrenia yielded a significant effect of seropositivity before onset and serointensity, but not IgM antibodies or gender. The amplitude of the OR was influenced by region and general seroprevalence. Moderators together accounted for 56% of the observed variance in study effects. After controlling for publication bias, the adjusted OR (1.43) in schizophrenia remained significant. CONCLUSION These findings suggest that T. gondii infection is associated with several psychiatric disorders and that in schizophrenia reactivation of latent T. gondii infection may occur.
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Affiliation(s)
- A L Sutterland
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - G Fond
- AP-HP, DHU Pe-PSY, Pôle de Psychiatrie et d'addictologie des Hôpitaux Universitaires H Mondor, INSERM U955, Eq 15 Psychiatrie Translationnelle, Université Paris Est-Créteil, Créteil, France.,Fondation Fondamental, Créteil, France
| | - A Kuin
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - M W J Koeter
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - R Lutter
- Departments of Experimental Immunology and Respiratory Medicine, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - T van Gool
- Department of Parasitology, Academic Medical Centre (AMC), Amsterdam, the Netherlands
| | - R Yolken
- Stanley Neurovirology Laboratory, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - A Szoke
- AP-HP, DHU Pe-PSY, Pôle de Psychiatrie et d'addictologie des Hôpitaux Universitaires H Mondor, INSERM U955, Eq 15 Psychiatrie Translationnelle, Université Paris Est-Créteil, Créteil, France.,Fondation Fondamental, Créteil, France
| | - M Leboyer
- AP-HP, DHU Pe-PSY, Pôle de Psychiatrie et d'addictologie des Hôpitaux Universitaires H Mondor, INSERM U955, Eq 15 Psychiatrie Translationnelle, Université Paris Est-Créteil, Créteil, France.,Fondation Fondamental, Créteil, France
| | - L de Haan
- Department of Psychiatry, Academic Medical Centre (AMC), Amsterdam, the Netherlands
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17
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Fine-mapping butyrophilin family genes revealed several polymorphisms influencing viral genotype selection in hepatitis C infection. Genes Immun 2015; 16:297-300. [PMID: 25928882 DOI: 10.1038/gene.2015.14] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 02/20/2015] [Accepted: 02/23/2015] [Indexed: 12/15/2022]
Abstract
Host-viral genetic interaction has a key role in hepatitis C infection (HCV) and maybe in the viral selection. In a preliminary GWAS analysis, we identified BTN3A2 rs9104 to be associated with HCV genotype 1. Therefore, our aim was to determine the influence of BTN family on the selection of HCV genotype. We performed a fine-mapping analysis of BTN gene region in a cohort of chronic HCV infection (N=841), validating significant results in another independent chronic HCV infection cohort (N=637), according to selection of viral genotype. BTN3A2 rs9104, BTN3A2 rs733528, BTN2A1 rs6929846, BTN2A1 rs7763910 and BTN3A3 rs13220495 were associated with viral genotype selection. Interestingly, BTN3A2 rs9104 GG genotype was closely related to genotype 1 infection (80.7% (394/488) compared with genotype 3 infection (53.5% (23/43); P=0.0001) in patients harboring IL28B-CT/TT genotype, although this effect was not observed in IL28B-CC genotype. Similarly, BTN3A3 rs13220495 CC genotype was linked to genotype 3 infection (100% (32/32)) compared to genotype 1 (87.3% (137/157); P=0.028) in patients harboring IL28B-CC genotype, but did not in IL28B-CT/TT genotype. Genetic variants in the butyrophilin family genes may alter susceptibility to infection, selecting HCV genotype and influencing disease progression. BTN3A2 rs9104 was strongly associated with genotype 1 infection and the haplotype BTN3A3 rs13220495 CC+IL28B genotype CC was universal in patients with hepatitis C genotype 3a.
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18
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Pollak TA, McCormack R, Peakman M, Nicholson TR, David AS. Prevalence of anti-N-methyl-D-aspartate (NMDA) receptor [corrected] antibodies in patients with schizophrenia and related psychoses: a systematic review and meta-analysis. Psychol Med 2014; 44:2475-2487. [PMID: 24330811 DOI: 10.1017/s003329171300295x] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an autoimmune condition caused by immunoglobulin (Ig)G antibodies directed against the NR1 subunit of the NMDA glutamate receptor. Approximately 65% of cases present with psychiatric symptoms, particularly psychosis. It remains to be established whether anti-NMDA receptor antibodies can cause a 'purely' psychotic illness without overt neurological symptoms. METHOD We conducted a systematic literature search to establish what proportion of patients with schizophrenia and related psychoses have antibodies directed against the NMDA receptor. Studies were included if (a) subjects had a diagnosis of schizophrenia, schizophrenia spectrum disorder or first-episode psychosis (FEP) using standard criteria, (b) serum was analysed for the presence of anti-NMDA receptor antibodies; and (c) the purpose of the study was to look for the presence of anti-NMDA receptor antibodies in patients with a primary psychiatric diagnosis without clinical signs of encephalitis. RESULTS Seven studies were included, comprising 1441 patients, of whom 115 [7.98%, 95% confidence interval (CI) 6.69-9.50] were anti-NMDA receptor antibody positive. Of these, 21 (1.46%, 95% CI 0.94-2.23) patients were positive for antibodies of the IgG subclass. Prevalence rates were greater in cases than controls only for IgG antibodies; other subclasses are of less certain aetiological relevance. There was significant heterogeneity in terms of patient characteristics and the antibody assay used. CONCLUSIONS A minority of patients with psychosis are anti-NMDA receptor antibody positive. It remains to be established whether this subset of patients differs from antibody-negative patients in terms of underlying pathology and response to antipsychotic treatment, and whether immunomodulatory treatments are effective in alleviating psychotic symptoms in this group.
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Affiliation(s)
- T A Pollak
- National Institute for Health Research (NIHR) Biomedical Research Centre, South London and Maudsley NHS FoundationTrust and Institute of Psychiatry, King's College London,UK
| | - R McCormack
- National Institute for Health Research (NIHR) Biomedical Research Centre, South London and Maudsley NHS FoundationTrust and Institute of Psychiatry, King's College London,UK
| | - M Peakman
- Department of Immunobiology,King's College London,UK
| | - T R Nicholson
- Section of Cognitive Neuropsychiatry, Department of Psychosis Studies,Institute of Psychiatry, King's College London,UK
| | - A S David
- Section of Cognitive Neuropsychiatry, Department of Psychosis Studies,Institute of Psychiatry, King's College London,UK
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Dickerson F, Stallings C, Origoni A, Vaughan C, Katsafanas E, Khushalani S, Yolken R. Antibodies to Toxoplasma gondii in individuals with mania. Bipolar Disord 2014; 16:129-36. [PMID: 24102676 DOI: 10.1111/bdi.12123] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Accepted: 07/02/2013] [Indexed: 01/01/2023]
Abstract
OBJECTIVES Increased rates of infection with Toxoplasma gondii have been found in individuals with schizophrenia as compared to control groups but this issue has not been studied in mania. METHODS We measured immunoglobulin G (IgG) and IgM class antibodies to T. gondii in 57 individuals with mania who were assessed at up to three time-points. We also measured these antibodies in 743 individuals in other psychiatric groups and in 314 non-psychiatric controls. T. gondii antibody levels were compared among groups by multivariate analyses. IgG class and IgM class antibodies to cytomegalovirus were also measured in the same samples. T. gondii antibody levels were also compared over time in the mania group. RESULTS The mania group had a significantly elevated level of IgM antibodies to T. gondii as compared to the control individuals without a psychiatric diagnosis [odds ratio (OR) = 2.33, p < 0.04 at hospital admission; and OR = 2.32, p < 0.02 at study entry during the hospital stay]. Elevated IgM class antibodies to T. gondii were not found in individuals with the other psychiatric diagnoses. We also did not find an increased level of IgG class antibodies to T. gondii or IgG or IgM class antibodies to CMV in the individuals with mania. Within the mania group, there was a significant difference between the prevalences of increased levels of T. gondii IgM at the baseline and the follow-up time-point (t = 2.97, p < 0.003). CONCLUSIONS Infection with T. gondii may confer risk for mania.
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Affiliation(s)
- Faith Dickerson
- Stanley Research Program, Sheppard Pratt Health System, Baltimore, MD, USA
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Horváth S, Mirnics K. Immune system disturbances in schizophrenia. Biol Psychiatry 2014; 75:316-23. [PMID: 23890736 PMCID: PMC3841236 DOI: 10.1016/j.biopsych.2013.06.010] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/06/2013] [Accepted: 06/19/2013] [Indexed: 12/12/2022]
Abstract
Epidemiological, genetic, transcriptome, postmortem, peripheral biomarker, and therapeutic studies of schizophrenia all point to a dysregulation of both innate and adaptive immune systems in the disease, and it is likely that these immune changes actively contribute to disease symptoms. Gene expression disturbances in the brain of subjects with schizophrenia show complex, region-specific changes with consistently replicated and potentially interdependent induction of serpin peptidase inhibitor, clade A member 3 (SERPINA3) and interferon inducible transmembrane protein (IFITM) family transcripts in the prefrontal cortex. Recent data suggest that IFITM3 expression is a critical mediator of maternal immune activation. Because the IFITM gene family is primarily expressed in the endothelial cells and meninges, and because the meninges play a critical role in interneuron development, we suggest that these two non-neuronal cell populations might play an important role in the disease pathophysiology. Finally, we propose that IFITM3 in particular might be a novel, appealing, knowledge-based drug target for treatment of schizophrenia.
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Affiliation(s)
- Szatmár Horváth
- Department of Psychiatry, Vanderbilt University, Nashville, TN 37232, USA,Department of Psychiatry, University of Szeged, 6725 Szeged, Hungary
| | - Károly Mirnics
- Department of Psychiatry, Vanderbilt University, Nashville, Tennessee; Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee; Department of Psychiatry, University of Szeged, 6725 Szeged, Hungary.
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Kodavali CV, Watson AM, Prasad KM, Celik C, Mansour H, Yolken RH, Nimgaonkar VL. HLA associations in schizophrenia: are we re-discovering the wheel? Am J Med Genet B Neuropsychiatr Genet 2014; 165B:19-27. [PMID: 24142843 DOI: 10.1002/ajmg.b.32195] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 08/02/2013] [Indexed: 01/18/2023]
Abstract
Associations between human leukocyte antigen (HLA) polymorphisms on chromosome 6p and schizophrenia (SZ) risk have been evaluated for over five decades. Numerous case-control studies from the candidate gene era analyzed moderately sized samples and reported nominally significant associations with several loci in the HLA region (sample sizes, n = 100-400). The risk conferred by individual alleles was modest (odds ratios < 2.0). The basis for the associations could not be determined, though connections with known immune and auto-immune abnormalities in SZ were postulated. Interest in the HLA associations has re-emerged following several recent genome-wide association studies (GWAS); which utilized 10- to 100-fold larger samples and also identified associations on the short arm of chromosome 6. Unlike the earlier candidate gene studies, the associations are statistically significant following correction for multiple comparisons. Like the earlier studies; they have modest effect sizes, raising questions about their utility in risk prediction or pathogenesis research. In this review, we summarize the GWAS and reflect on possible bases for the associations. Suggestions for future research are discussed. We favor, in particular; efforts to evaluate local population sub-structure as well as further evaluation of immune-related variables in future studies.
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Affiliation(s)
- Chowdari V Kodavali
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, Pittsburgh, Pennsylvania
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