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He Q, Li R, Zhong N, Ma J, Nie F, Zhang R. The role and molecular mechanisms of the early growth response 3 gene in schizophrenia. Am J Med Genet B Neuropsychiatr Genet 2024; 195:e32969. [PMID: 38327141 DOI: 10.1002/ajmg.b.32969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 01/15/2024] [Accepted: 01/22/2024] [Indexed: 02/09/2024]
Abstract
Schizophrenia is a chronic, debilitating mental illness caused by both genetic and environmental factors. Genetic factors play a major role in schizophrenia development. Early growth response 3 (EGR3) is a member of the EGR family, which is associated with schizophrenia. Accumulating studies have investigated the relationship between EGR3 and schizophrenia. However, the role of EGR3 in schizophrenia pathogenesis remains unclear. In the present review, we focus on the progress of research related to the role of EGR3 in schizophrenia, including association studies between EGR3 and schizophrenia, abnormal gene expressional analysis of EGR3 in schizophrenia, biological function studies of EGR3 in schizophrenia, the molecular regulatory mechanism of EGR3 and schizophrenia susceptibility candidate genes, and possible role of EGR3 in the immune system function in schizophrenia. In summary, EGR3 is a schizophrenia risk candidate factor and has comprehensive regulatory roles in schizophrenia pathogenesis. Further studies investigating the molecular mechanisms of EGR3 in schizophrenia are warranted for understanding the pathophysiology of this disorder as well as the development of new therapeutic strategies for the treatment and control of this disorder.
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Affiliation(s)
- Qi He
- School of Basic Medicine, Shaanxi Key Laboratory of Acupuncture and Medicine, Shannxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Ruochun Li
- Department of Medical Technology, Guiyang Healthcare Vocational University, Guiyang, Guizhou, China
| | - Nannan Zhong
- Department of Medical Technology, Guiyang Healthcare Vocational University, Guiyang, Guizhou, China
| | - Jie Ma
- Department of Electron Microscope, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Fayi Nie
- School of Basic Medicine, Shaanxi Key Laboratory of Acupuncture and Medicine, Shannxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Rui Zhang
- Department of Medical Technology, Guiyang Healthcare Vocational University, Guiyang, Guizhou, China
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2
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Identification of activity-induced Egr3-dependent genes reveals genes associated with DNA damage response and schizophrenia. Transl Psychiatry 2022; 12:320. [PMID: 35941129 PMCID: PMC9360026 DOI: 10.1038/s41398-022-02069-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/05/2022] [Accepted: 07/12/2022] [Indexed: 11/23/2022] Open
Abstract
Bioinformatics and network studies have identified the immediate early gene transcription factor early growth response 3 (EGR3) as a master regulator of genes differentially expressed in the brains of patients with neuropsychiatric illnesses ranging from schizophrenia and bipolar disorder to Alzheimer's disease. However, few studies have identified and validated Egr3-dependent genes in the mammalian brain. We have previously shown that Egr3 is required for stress-responsive behavior, memory, and hippocampal long-term depression in mice. To identify Egr3-dependent genes that may regulate these processes, we conducted an expression microarray on hippocampi from wildtype (WT) and Egr3-/- mice following electroconvulsive seizure (ECS), a stimulus that induces maximal expression of immediate early genes including Egr3. We identified 69 genes that were differentially expressed between WT and Egr3-/- mice one hour following ECS. Bioinformatic analyses showed that many of these are altered in, or associated with, schizophrenia, including Mef2c and Calb2. Enrichr pathway analysis revealed the GADD45 (growth arrest and DNA-damage-inducible) family (Gadd45b, Gadd45g) as a leading group of differentially expressed genes. Together with differentially expressed genes in the AP-1 transcription factor family genes (Fos, Fosb), and the centromere organization protein Cenpa, these results revealed that Egr3 is required for activity-dependent expression of genes involved in the DNA damage response. Our findings show that EGR3 is critical for the expression of genes that are mis-expressed in schizophrenia and reveal a novel requirement for EGR3 in the expression of genes involved in activity-induced DNA damage response.
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3
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Acute sleep deprivation upregulates serotonin 2A receptors in the frontal cortex of mice via the immediate early gene Egr3. Mol Psychiatry 2022; 27:1599-1610. [PMID: 35001075 PMCID: PMC9210263 DOI: 10.1038/s41380-021-01390-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/27/2021] [Accepted: 11/12/2021] [Indexed: 01/07/2023]
Abstract
Serotonin 2A receptors (5-HT2ARs) mediate the hallucinogenic effects of psychedelic drugs and are a key target of the leading class of medications used to treat psychotic disorders. These findings suggest that dysfunction of 5-HT2ARs may contribute to the symptoms of schizophrenia, a mental illness characterized by perceptual and cognitive disturbances. Indeed, numerous studies have found that 5-HT2ARs are reduced in the brains of individuals with schizophrenia. However, the mechanisms that regulate 5-HT2AR expression remain poorly understood. Here, we show that a physiologic environmental stimulus, sleep deprivation, significantly upregulates 5-HT2AR levels in the mouse frontal cortex in as little as 6-8 h (for mRNA and protein, respectively). This induction requires the activity-dependent immediate early gene transcription factor early growth response 3 (Egr3) as it does not occur in Egr3 deficient (-/-) mice. Using chromatin immunoprecipitation, we show that EGR3 protein binds to the promoter of Htr2a, the gene that encodes the 5-HT2AR, in the frontal cortex in vivo, and drives expression of in vitro reporter constructs via two EGR3 binding sites in the Htr2a promoter. These results suggest that EGR3 directly regulates Htr2a expression, and 5-HT2AR levels, in the frontal cortex in response to physiologic stimuli. Analysis of publicly available post-mortem gene expression data revealed that both EGR3 and HTR2A mRNA are reduced in the prefrontal cortex of schizophrenia patients compared to controls. Together these findings suggest a mechanism by which environmental stimuli alter levels of a brain receptor that may mediate the symptoms, and treatment, of mental illness.
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4
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Nie F, Zhang Q, Ma J, Wang P, Gu R, Han J, Zhang R. Schizophrenia risk candidate EGR3 is a novel transcriptional regulator of RELN and regulates neurite outgrowth via the Reelin signal pathway in vitro. J Neurochem 2020; 157:1745-1758. [PMID: 33113163 DOI: 10.1111/jnc.15225] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/06/2020] [Accepted: 10/15/2020] [Indexed: 01/09/2023]
Abstract
Schizophrenia is a severe psychiatric disorder with a strong hereditary component that affects approximately 1% of the world's population. The disease is most likely caused by the altered expression of a number of genes that function at the level of biological pathways or gene networks. Transcription factors (TF) are indispensable regulators of gene expression. EGR3 is a TF associated with schizophrenia. In the current study, DNA microarray and ingenuity pathway analyses (IPA) demonstrated that EGR3 regulates Reelin signaling pathway in SH-SY5Y cells. ChIP and luciferase reporter studies confirmed that EGR3 directly binds to the promoter region of RELN thereby activating RELN expression. The expression of both EGR3 and RELN was decreased during neuronal differentiation induced by retinoic acid (RA) in SH-SY5Y cells, and EGR3 over-expression reduced neurite outgrowth which could be partially reversed by the knockdown of RELN. The expression levels of EGR3 and RELN in peripheral blood of subjects with schizophrenia were found to be down-regulated (compared with healthy controls), and were positively correlated. Furthermore, data mining from public databases revealed that the expression levels of EGR3 and RELN were presented a positive correlation in post-mortem brain tissue of subjects with schizophrenia. Taken together, this study suggests that EGR3 is a novel TF of the RELN gene and regulates neurite outgrowth via the Reelin signaling pathway. Our findings contribute to the understanding of the regulatory role of EGR3 in the pathophysiology and molecular mechanisms of schizophrenia, and potentially to the development of new therapies and diagnostic biomarkers for the disorder.
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Affiliation(s)
- Fayi Nie
- School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Qiaoxia Zhang
- School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Jie Ma
- School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.,Medical Research Center, Xi'an No. 3 Hospital, Xi'an, Shaanxi, China
| | - Pengjie Wang
- School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Ruiying Gu
- School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Jing Han
- School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Rui Zhang
- Translational Medicine Center, Hong Hui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
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Dondé C, Brunelin J, Mondino M, Cellard C, Rolland B, Haesebaert F. The effects of acute nicotine administration on cognitive and early sensory processes in schizophrenia: a systematic review. Neurosci Biobehav Rev 2020; 118:121-133. [PMID: 32739422 DOI: 10.1016/j.neubiorev.2020.07.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 06/18/2020] [Accepted: 07/25/2020] [Indexed: 12/01/2022]
Abstract
Nicotine use, which is mostly done through smoking tobacco, is among the most burdensome comorbidities of schizophrenia. However, the ways in which nicotine affects the cognitive and early sensory alterations found in this illness are still debated. After conducting a systematic literature search, 29 studies were selected. These studies involve individuals with schizophrenia who underwent cognitive and/or early sensory function assessments after acute nicotine administration and include 560 schizophrenia subjects and 346 non-schizophrenia controls. The findings highlight that a single dose of nicotine can improve a range of cognitive functions in schizophrenia subjects, such as attention, working memory, and executive functions, with attention being the most responsive domain. In addition, nicotine can modulate early detection of changes in the sensory environment at both the auditory and visual levels. Nevertheless, effects vary strongly depending on the type of neuropsychological assessment and nicotine intake conditions used in each study. The current findings suggest the need to consider a potential decrease of cognitive and early sensory performance when patients with schizophrenia quit smoking.
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Affiliation(s)
- Clément Dondé
- Univ. Grenoble Alpes, F-38000 Grenoble, France; Psychiatry Department, CHU Grenoble Alpes, F-38000 Grenoble, France.
| | - Jérôme Brunelin
- INSERM, U1028, CNRS, UMR5292, Lyon Neuroscience Research Center, Psychiatric Disorders: from Resistance to Response Team, Lyon, F-69000, France; University Lyon 1, Villeurbanne, F-69000, France; Centre Hospitalier Le Vinatier, Bron, France.
| | - Marine Mondino
- INSERM, U1028, CNRS, UMR5292, Lyon Neuroscience Research Center, Psychiatric Disorders: from Resistance to Response Team, Lyon, F-69000, France; University Lyon 1, Villeurbanne, F-69000, France; Centre Hospitalier Le Vinatier, Bron, France.
| | | | - Benjamin Rolland
- INSERM, U1028, CNRS, UMR5292, Lyon Neuroscience Research Center, Psychiatric Disorders: from Resistance to Response Team, Lyon, F-69000, France; University Lyon 1, Villeurbanne, F-69000, France; Centre Hospitalier Le Vinatier, Bron, France.
| | - Frédéric Haesebaert
- INSERM, U1028, CNRS, UMR5292, Lyon Neuroscience Research Center, Psychiatric Disorders: from Resistance to Response Team, Lyon, F-69000, France; University Lyon 1, Villeurbanne, F-69000, France; Centre Hospitalier Le Vinatier, Bron, France.
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6
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Delorme TC, Srivastava LK, Cermakian N. Are Circadian Disturbances a Core Pathophysiological Component of Schizophrenia? J Biol Rhythms 2020; 35:325-339. [DOI: 10.1177/0748730420929448] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Schizophrenia is a multifactorial disorder caused by a combination of genetic variations and exposure to environmental insults. Sleep and circadian rhythm disturbances are a prominent and ubiquitous feature of many psychiatric disorders, including schizophrenia. There is growing interest in uncovering the mechanistic link between schizophrenia and circadian rhythms, which may directly affect disorder outcomes. In this review, we explore the interaction between schizophrenia and circadian rhythms from 2 complementary angles. First, we review evidence that sleep and circadian rhythm disturbances constitute a fundamental component of schizophrenia, as supported by both human studies and animal models with genetic mutations related to schizophrenia. Second, we discuss the idea that circadian rhythm disruption interacts with existing risk factors for schizophrenia to promote schizophrenia-relevant behavioral and neurobiological abnormalities. Understanding the mechanistic link between schizophrenia and circadian rhythms will have implications for mitigating risk to the disorder and informing the development of circadian-based therapies.
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Affiliation(s)
- Tara C. Delorme
- Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
- Douglas Mental Health University Institute, Montréal, Québec, Canada
| | - Lalit K. Srivastava
- Douglas Mental Health University Institute, Montréal, Québec, Canada
- Department of Psychiatry, McGill University, Montréal, Québec, Canada
| | - Nicolas Cermakian
- Douglas Mental Health University Institute, Montréal, Québec, Canada
- Department of Psychiatry, McGill University, Montréal, Québec, Canada
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7
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Liu L, Wen Y, Ning Y, Li P, Cheng B, Cheng S, Zhang L, Ma M, Qi X, Liang C, Yang T, Chen X, Tan L, Shen H, Tian Q, Deng HW, Ma X, Zhang F, Zhu F. A trans-ethnic two-stage polygenetic scoring analysis detects genetic correlation between osteoporosis and schizophrenia. Clin Transl Med 2020; 9:21. [PMID: 32107650 PMCID: PMC7046891 DOI: 10.1186/s40169-020-00272-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 02/17/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUNDS To explore the genetic correlation between schizophrenia (SCZ) and osteoporosis (OP). DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS We conducted a trans-ethnic two-stage genetic correlation analysis of OP and SCZ, totally invoking 2286 Caucasia subjects in discovery stage and 4124 Chinese subjects in replication stage. The bone mineral density (BMD) and bone area values of ulna & radius, hip and spine were measured using Hologic 4500W dual energy X-ray absorptiometry machine. SCZ was diagnosed according to DSM-IV criteria. For the genome-wide association study (GWAS) of Caucasian OP, Chinese OP and Chinese SCZ, SNP genotyping was performed using Affymetrix SNP 6.0 array. For the GWAS of Caucasian SCZ, SNP genotyping was conducted using the Affymetrix 5.0 array, Affymetrix 6.0 array and Illumina 550 K array. Polygenetic risk scoring (PRS) analysis was conducted by PRSice software. Also, Linkage disequilibrium score regression (LD Score regression) analysis was performed to evaluate the genetic correlation between OP and SCZ. Multi-trait analysis of GWAS (MTAG) was performed to detect novel candidate genes for osteoporosis and SCZ. RESULTS In the Caucasia discovery samples, significant genetic correlations were observed for ulna & radius BMD vs. SCZ (P value = 0.010), ulna & radius area vs. SCZ (P value = 0.031). In the Chinese replication samples, we observed significant correlation for ulna & radius area vs. SCZ (P value = 0.019). In addition, LD Score regression also identified significant genetic correlations between SCZ and bone phenotypes in Caucasian and Chinese sample respectively. MTAG analysis identified several novel candidate genes, such as CTNNA2 (MTAG P value = 2.24 × 10-6) for SCZ and FADS2 (MTAG P value = 2.66 × 10-7) for osteoporosis. CONCLUSIONS Our study results support the overlapped genetic basis for osteoporosis and SCZ, and provide novel clues for elucidating the biological mechanism of increased osteoporosis risk in SCZ patients.
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Affiliation(s)
- Li Liu
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Yan Wen
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Yujie Ning
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Ping Li
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Bolun Cheng
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Shiqiang Cheng
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Lu Zhang
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Mei Ma
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Xin Qi
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Chujun Liang
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China
| | - Tielin Yang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, People's Republic of China
| | - Xiangding Chen
- Laboratory of Molecular and Statistical Genetics, College of Life Sciences, Hunan Normal University, Changsha, People's Republic of China
| | - Lijun Tan
- Laboratory of Molecular and Statistical Genetics, College of Life Sciences, Hunan Normal University, Changsha, People's Republic of China
| | - Hui Shen
- Center for Bioinformatics and Genomics, Department of Global Biostatistics and Data Science, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Qing Tian
- Center for Bioinformatics and Genomics, Department of Global Biostatistics and Data Science, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Hong-Wen Deng
- Center for Bioinformatics and Genomics, Department of Global Biostatistics and Data Science, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Xiancang Ma
- Department of Psychiatry, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Feng Zhang
- School of Public Health, Xi'an Jiaotong University Health Science Center, Yanta West Road 76, Xi'an, 710061, People's Republic of China.
| | - Feng Zhu
- Center for Translational Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, No. 277 Yanta West Road, Xi'an, 710061, People's Republic of China.
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Gene Regulatory Network of Dorsolateral Prefrontal Cortex: a Master Regulator Analysis of Major Psychiatric Disorders. Mol Neurobiol 2019; 57:1305-1316. [PMID: 31728928 DOI: 10.1007/s12035-019-01815-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/11/2019] [Indexed: 10/25/2022]
Abstract
Despite the strong genetic component of psychiatric disorders, traditional genetic studies have failed to find individual genes of large effect size. Thus, alternative methods, using bioinformatics, have been proposed to solve these biological puzzles. Of these, here we employ systems biology-based approaches to identify potential master regulators (MRs) of bipolar disorder (BD), schizophrenia (SZ), and major depressive disorder (MDD), their association with biological processes and their capacity to differentiate disorders' phenotypes. High-throughput gene expression data was used to reconstruct standard human dorsolateral prefrontal cortex regulatory transcriptional network, which was then queried for regulatory units and MRs associated with the psychiatric disorders of interest. Furthermore, the activity status (active or repressed) of MR candidates was obtained and used in cluster analysis to characterize disease phenotypes. Finally, we explored the biological processes modulated by the MRs using functional enrichment analysis. Thirty-one, thirty-four, and fifteen MR candidates were identified in BD, SZ, and MDD, respectively. The activity state of these MRs grouped the illnesses in three clusters: MDD only, mostly BD, and a third one with BD and SZ. While BD and SZ share several biological processes related to ion transport and homeostasis, synapse, and immune function, SZ showed peculiar enrichment of processes related to cytoskeleton and neuronal structure. Meanwhile, MDD presented mostly processes related to glial development and fatty acid metabolism. Our findings suggest notable differences in functional enrichment between MDD and BD/SZ. Furthermore, similarities between BD and SZ may impose particular challenges in attempts to discriminate these pathologies based solely on their transcriptional profiles. Nevertheless, we believe that systems-oriented approaches are promising strategies to unravel the pathophysiology peculiarities underlying mental illnesses and reveal therapeutic targets.
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9
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Postmortem transcriptional profiling reveals widespread increase in inflammation in schizophrenia: a comparison of prefrontal cortex, striatum, and hippocampus among matched tetrads of controls with subjects diagnosed with schizophrenia, bipolar or major depressive disorder. Transl Psychiatry 2019; 9:151. [PMID: 31123247 PMCID: PMC6533277 DOI: 10.1038/s41398-019-0492-8] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 05/03/2019] [Indexed: 11/30/2022] Open
Abstract
Psychiatric disorders such as schizophrenia (SCZ), bipolar disorder (BD), and major depressive disorder (MDD) arise from complex interactions between genetic and environmental factors. Common genetic variants associated with multiple psychiatric disorders suggest that shared genetic architecture could contribute to divergent clinical syndromes. To evaluate shared transcriptional alterations across connected brain regions, Affymetrix microarrays were used to profile postmortem dorsolateral prefrontal cortex (DLPFC), hippocampus, and associative striatum from 19 well-matched tetrads of subjects with SCZ, BD, MDD, or unaffected controls. SCZ subjects showed a substantial burden of differentially expressed genes across all examined brain regions with the greatest effects in hippocampus, whereas BD and MDD showed less robust alterations. Pathway analysis of transcriptional profiles compared across diagnoses demonstrated commonly enriched pathways between all three disorders in hippocampus, significant overlap between SCZ and BD in DLPFC, but no significant overlap of enriched pathways between disorders in striatum. SCZ samples showed increased expression of transcripts associated with inflammation across all brain regions examined, which was not evident in BD or MDD, or in rat brain following chronic dosing with antipsychotic drugs. Several markers of inflammation were confirmed by RT-PCR in hippocampus, including S100A8/9, IL-6, MAFF, APOLD1, IFITM3, and BAG3. A cytokine ELISA panel showed significant increases in IL-2 and IL-12p70 protein content in hippocampal tissue collected from same SCZ subjects when compared to matched control subjects. These data suggest an overlapping subset of dysregulated pathways across psychiatric disorders; however, a widespread increase in inflammation appears to be a specific feature of the SCZ brain and is not likely to be attributable to chronic antipsychotic drug treatment.
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10
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Maple AM, Rowe RK, Lifshitz J, Fernandez F, Gallitano AL. Influence of Schizophrenia-Associated Gene Egr3 on Sleep Behavior and Circadian Rhythms in Mice. J Biol Rhythms 2018; 33:662-670. [PMID: 30318979 DOI: 10.1177/0748730418803802] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Up to 80% of people meeting DSM-IV definitions for schizophrenia will exhibit difficulties with sleep, along with a breakdown in circadian entrainment and rhythmicity. The changes to the sleep and circadian systems in this population are thought to be interdependent, as evidenced by the frequent use of the combined term "sleep and circadian rhythm disruption" or "SCRD" to describe their occurrence. To understand links between sleep and circadian problems in the schizophrenia population, we analyzed the duration and rhythmicity of sleep behavior in mice lacking function of the immediate early gene early growth response 3 ( Egr3). EGR3 has been associated with schizophrenia risk in humans, and Egr3-deficient (-/-) mice display various features of schizophrenia that are responsive to antipsychotic treatment. While Egr3-/- mice slept less than their wildtype (WT) littermates, they showed no evidence of circadian disorganization; in fact, circadian rhythms of activity were more robust in these mice compared with WT, as measured by time series analysis and the relative amplitude index of Van Someren's suite of non-parametric circadian rhythm analyses. Differences in circadian robustness were maintained when the animals were transferred to several weeks of housing under constant darkness or constant light. Together, our results suggest that Egr3-/- mice retain control over the circadian timekeeping of sleep and wake, while showing impaired sleep. The findings are compatible with those from a surprising array of mouse models of schizophrenia and raise the possibility that SCRD may be 2 separate disorders in the schizophrenia population requiring different treatment strategies.
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Affiliation(s)
- Amanda M Maple
- Department of Basic Medical Sciences, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona
| | - Rachel K Rowe
- Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona.,Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona.,Phoenix Veteran Affairs Health Care System, Phoenix, Arizona
| | - Jonathan Lifshitz
- Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona.,Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona.,Phoenix Veteran Affairs Health Care System, Phoenix, Arizona.,Interdisciplinary Graduate Program in Neuroscience, Arizona State University, Tempe, Arizona
| | - Fabian Fernandez
- Departments of Psychology and Neurology, BIO5 Institute, and The Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, Arizona
| | - Amelia L Gallitano
- Department of Basic Medical Sciences, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona.,Interdisciplinary Graduate Program in Neuroscience, Arizona State University, Tempe, Arizona
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11
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Identifying the genetic risk factors for treatment response to lurasidone by genome-wide association study: A meta-analysis of samples from three independent clinical trials. Schizophr Res 2018; 199:203-213. [PMID: 29730043 DOI: 10.1016/j.schres.2018.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/22/2018] [Accepted: 04/03/2018] [Indexed: 01/05/2023]
Abstract
A genome-wide association study (GWAS) of response of schizophrenia patients to the atypical antipsychotic drug, lurasidone, based on two double-blind registration trials, identified SNPs from four classes of genes as predictors of efficacy, but none were genome wide significant (GWS). After inclusion of data from a third lurasidone trial, meta-analysis identified a GWS marker and other findings consistent with our first study. The primary end-point was change in Total Positive and Negative Syndrome Scale (PANSS) between baseline and last observation carried forward. rs4736253, a genetic locus near KCNK9, encoding the K2P9.1 potassium channel, with a role in cognition and neurodevelopment, was the top marker in patients of European ancestry (EUR) (n = 264), reaching GWS (p = 4.78 × 10-8). rs10180106 (p = 4.92 × 10-7), located at an intron region of CTNNA2, a SCZ risk gene important for dendritic spine stabilization, was one of other best response markers for EUR patients. SNPs at STXBP5L (rs511841, p = 2.63 × 10-7) were the top markers for patients of African ancestry (n = 158). The association between PTPRD, NRG1, and MAGI1 previously reported to be related to response to lurasidone in the first two trials, showed a trend of significant association in the third trial. None of these genetic loci showed significant associations with clinical response in the corresponding placebo groups (n = 107 for EUR; n = 58 for AFR). This meta-analysis yielded the first GWAS-based GWS biomarker for lurasidone response and additional support for the conclusion that genes related to synaptic biology and/or risk for SCZ are the strongest predictors of response to lurasidone in schizophrenia patients.
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12
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Grønli J, Schmidt MA, Wisor JP. State-Dependent Modulation of Visual Evoked Potentials in a Rodent Genetic Model of Electroencephalographic Instability. Front Syst Neurosci 2018; 12:36. [PMID: 30158860 PMCID: PMC6104170 DOI: 10.3389/fnsys.2018.00036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/17/2018] [Indexed: 12/29/2022] Open
Abstract
Despite normal sleep timing and duration, Egr3-deficient (Egr3−/−) mice exhibit electroencephalographic (EEG) characteristics of reduced arousal, including elevated slow wave (1–4 Hz) activity during wakefulness. Here we show that these mice exhibit state-dependent instability in the EEG. Intermittent surges in EEG power were found in Egr3−/− mice during wakefulness and rapid eye movement sleep, most prominently in the beta (15–35 Hz) range compared to wild type (Egr3+/+) mice. Such surges did not coincide with sleep onset, as the surges were not associated with cessation of electromyographic tone. Cortical processing of sensory information by visual evoked responses (VEP) were found to vary as a function of vigilance state, being of higher magnitude during slow wave sleep (SWS) than wakefulness and rapid eye movement sleep. VEP responses were significantly larger during quiet wakefulness than active wakefulness, in both Egr3−/− mice and Egr3+/+ mice. EEG synchronization in the beta range, previously linked to the accumulation of sleep need over time, predicted VEP magnitude. Egr3−/− mice not only displayed elevated beta activity, but in quiet wake, this elevated beta activity coincides with an elevated evoked response similar to that of animals in SWS. These data confirm that (a) VEPs vary as a function of vigilance state, and (b) beta activity in the EEG is a predictor of state-dependent modulation of visual information processing. The phenotype of Egr3−/− mice indicates that Egr3 is a genetic regulator of these phenomena.
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Affiliation(s)
- Janne Grønli
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - Michelle A Schmidt
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States.,Sleep and Performance Research Center, Washington State University, Spokane, WA, United States
| | - Jonathan P Wisor
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, United States.,Sleep and Performance Research Center, Washington State University, Spokane, WA, United States
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Meyers KT, Marballi KK, Brunwasser SJ, Renda B, Charbel M, Marrone DF, Gallitano AL. The Immediate Early Gene Egr3 Is Required for Hippocampal Induction of Bdnf by Electroconvulsive Stimulation. Front Behav Neurosci 2018; 12:92. [PMID: 29867393 PMCID: PMC5958205 DOI: 10.3389/fnbeh.2018.00092] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 04/23/2018] [Indexed: 01/19/2023] Open
Abstract
Early growth response 3 (Egr3) is an immediate early gene (IEG) that is regulated downstream of a cascade of genes associated with risk for psychiatric disorders, and dysfunction of Egr3 itself has been implicated in schizophrenia, bipolar disorder, and depression. As an activity-dependent transcription factor, EGR3 is poised to regulate the neuronal expression of target genes in response to environmental events. In the current study, we sought to identify a downstream target of EGR3 with the goal of further elucidating genes in this biological pathway relevant for psychiatric illness risk. We used electroconvulsive stimulation (ECS) to induce high-level expression of IEGs in the brain, and conducted expression microarray to identify genes differentially regulated in the hippocampus of Egr3-deficient (-/-) mice compared to their wildtype (WT) littermates. Our results replicated previous work showing that ECS induces high-level expression of the brain-derived neurotrophic factor (Bdnf) in the hippocampus of WT mice. However, we found that this induction is absent in Egr3-/- mice. Quantitative real-time PCR (qRT-PCR) validated the microarray results (performed in males) and replicated the findings in two separate cohorts of female mice. Follow-up studies of activity-dependent Bdnf exons demonstrated that ECS-induced expression of both exons IV and VI requires Egr3. In situ hybridization demonstrated high-level cellular expression of Bdnf in the hippocampal dentate gyrus following ECS in WT, but not Egr3-/-, mice. Bdnf promoter analysis revealed eight putative EGR3 binding sites in the Bdnf promoter, suggesting a mechanism through which EGR3 may directly regulate Bdnf gene expression. These findings do not appear to result from a defect in the development of hippocampal neurons in Egr3-/- mice, as cell counts in tissue sections stained with anti-NeuN antibodies, a neuron-specific marker, did not differ between Egr3-/- and WT mice. In addition, Sholl analysis and counts of dendritic spines in golgi-stained hippocampal sections revealed no difference in dendritic morphology or synaptic spine density in Egr3-/-, compared to WT, mice. These findings indicate that Egr3 is required for ECS-induced expression of Bdnf in the hippocampus and suggest that Bdnf may be a downstream gene in our previously identified biologically pathway for psychiatric illness susceptibility.
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Affiliation(s)
- Kimberly T Meyers
- Department of Basic Medical Sciences, College of Medicine Phoenix, University of Arizona, Phoenix, AZ, United States.,Interdisciplinary Graduate Program in Neuroscience, Arizona State University, Tempe, AZ, United States
| | - Ketan K Marballi
- Department of Basic Medical Sciences, College of Medicine Phoenix, University of Arizona, Phoenix, AZ, United States
| | - Samuel J Brunwasser
- Department of Basic Medical Sciences, College of Medicine Phoenix, University of Arizona, Phoenix, AZ, United States.,Medical Scientist Training Program, School of Medicine, Washington University in St. Louis, St. Louis, MO, United States
| | - Briana Renda
- Department of Psychology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Milad Charbel
- Department of Basic Medical Sciences, College of Medicine Phoenix, University of Arizona, Phoenix, AZ, United States.,Barrett, The Honors college, Arizona State University, Tempe, AZ, United States
| | - Diano F Marrone
- Department of Psychology, Wilfrid Laurier University, Waterloo, ON, Canada.,Evelyn F. McKnight Brain Institute, The University of Arizona, Tucson, AZ, United States
| | - Amelia L Gallitano
- Department of Basic Medical Sciences, College of Medicine Phoenix, University of Arizona, Phoenix, AZ, United States
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15
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Marballi KK, Gallitano AL. Immediate Early Genes Anchor a Biological Pathway of Proteins Required for Memory Formation, Long-Term Depression and Risk for Schizophrenia. Front Behav Neurosci 2018; 12:23. [PMID: 29520222 PMCID: PMC5827560 DOI: 10.3389/fnbeh.2018.00023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/29/2018] [Indexed: 01/02/2023] Open
Abstract
While the causes of myriad medical and infectious illnesses have been identified, the etiologies of neuropsychiatric illnesses remain elusive. This is due to two major obstacles. First, the risk for neuropsychiatric disorders, such as schizophrenia, is determined by both genetic and environmental factors. Second, numerous genes influence susceptibility for these illnesses. Genome-wide association studies have identified at least 108 genomic loci for schizophrenia, and more are expected to be published shortly. In addition, numerous biological processes contribute to the neuropathology underlying schizophrenia. These include immune dysfunction, synaptic and myelination deficits, vascular abnormalities, growth factor disruption, and N-methyl-D-aspartate receptor (NMDAR) hypofunction. However, the field of psychiatric genetics lacks a unifying model to explain how environment may interact with numerous genes to influence these various biological processes and cause schizophrenia. Here we describe a biological cascade of proteins that are activated in response to environmental stimuli such as stress, a schizophrenia risk factor. The central proteins in this pathway are critical mediators of memory formation and a particular form of hippocampal synaptic plasticity, long-term depression (LTD). Each of these proteins is also implicated in schizophrenia risk. In fact, the pathway includes four genes that map to the 108 loci associated with schizophrenia: GRIN2A, nuclear factor of activated T-cells (NFATc3), early growth response 1 (EGR1) and NGFI-A Binding Protein 2 (NAB2); each of which contains the "Index single nucleotide polymorphism (SNP)" (most SNP) at its respective locus. Environmental stimuli activate this biological pathway in neurons, resulting in induction of EGR immediate early genes: EGR1, EGR3 and NAB2. We hypothesize that dysfunction in any of the genes in this pathway disrupts the normal activation of Egrs in response to stress. This may result in insufficient electrophysiologic, immunologic, and neuroprotective, processes that these genes normally mediate. Continued adverse environmental experiences, over time, may thereby result in neuropathology that gives rise to the symptoms of schizophrenia. By combining multiple genes associated with schizophrenia susceptibility, in a functional cascade triggered by neuronal activity, the proposed biological pathway provides an explanation for both the polygenic and environmental influences that determine the complex etiology of this mental illness.
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Affiliation(s)
- Ketan K. Marballi
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, United States
| | - Amelia L. Gallitano
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, United States
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Pfaffenseller B, Kapczinski F, Gallitano AL, Klamt F. EGR3 Immediate Early Gene and the Brain-Derived Neurotrophic Factor in Bipolar Disorder. Front Behav Neurosci 2018; 12:15. [PMID: 29459824 PMCID: PMC5807664 DOI: 10.3389/fnbeh.2018.00015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 01/17/2018] [Indexed: 01/09/2023] Open
Abstract
Bipolar disorder (BD) is a severe psychiatric illness with a consistent genetic influence, involving complex interactions between numerous genes and environmental factors. Immediate early genes (IEGs) are activated in the brain in response to environmental stimuli, such as stress. The potential to translate environmental stimuli into long-term changes in brain has led to increased interest in a potential role for these genes influencing risk for psychiatric disorders. Our recent finding using network-based approach has shown that the regulatory unit of early growth response gene 3 (EGR3) of IEGs family was robustly repressed in postmortem prefrontal cortex of BD patients. As a central transcription factor, EGR3 regulates an array of target genes that mediate critical neurobiological processes such as synaptic plasticity, memory and cognition. Considering that EGR3 expression is induced by brain-derived neurotrophic factor (BDNF) that has been consistently related to BD pathophysiology, we suggest a link between BDNF and EGR3 and their potential role in BD. A growing body of data from our group and others has shown that peripheral BDNF levels are reduced during mood episodes and also with illness progression. In this same vein, BDNF has been proposed as an important growth factor in the impaired cellular resilience related to BD. Taken together with the fact that EGR3 regulates the expression of the neurotrophin receptor p75NTR and may also indirectly induce BDNF expression, here we propose a feed-forward gene regulatory network involving EGR3 and BDNF and its potential role in BD.
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Affiliation(s)
- Bianca Pfaffenseller
- Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Flavio Kapczinski
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, ON, Canada
| | - Amelia L Gallitano
- Department of Basic Medical Sciences, College of Medicine, University of Arizona, Phoenix, AZ, United States
| | - Fábio Klamt
- Laboratory of Cellular Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Association of NKAPL, TSPAN18, and MPC2 gene variants with schizophrenia based on new data and a meta-analysis in Han Chinese. Acta Neuropsychiatr 2017; 29:87-94. [PMID: 27460766 DOI: 10.1017/neu.2016.36] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Schizophrenia (SZ) is suggested to be a complex polygenetic disorder with high heritability. Genome-wide association studies have found that the rs1635, rs11038167, and rs10489202 polymorphisms are associated with SZ in Han Chinese. However, results of validation studies are inconsistent. This study aimed to test the association between the NKAPL rs1635, TSPAN18 rs11038167, and MPC2 rs10489202 polymorphisms and SZ in a Chinese population. METHODS This study contained 700 unrelated SZ patients (300 Zhuang and 400 Han) and 700 gender- and age-matched controls (300 Zhuang and 400 Han). The polymorphisms in TSPAN18 (rs11038167), NKAPL (rs1635), and MPC2 (rs10489202) were genotyped using the Sequenom MassARRAY method. Statistical analyses were performed with PLINK program and SPSS l6.0 for Windows. STATA11.1 was used for meta-analysis. RESULTS No statistically significant difference was found in different allele and genotype frequencies of rs1635, rs11038167, and rs10489202 between SZ cases and controls of Zhuang and Han ethnicities and the total samples (all p>0.05). Further meta-analysis suggested that single-nucleotide polymorphism rs10489202 was significantly associated with SZ in a Han Chinese population (p OR=0.002). CONCLUSIONS Our case-control study failed to validate the significant association of NKAPL rs1635, TSPAN18 rs11038167, and MPC2 rs10489202 polymorphisms with SZ susceptibility in the southern Zhuang or Han Chinese population. However, meta-analysis showed a significant association between MPC2 variant rs10489202 and SZ susceptibility in Han Chinese.
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18
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Abstract
Epidemiological studies and mouse models suggest that maternal immune activation, induced clinically through prenatal exposure to one of several infectious diseases, is a risk factor in the development of schizophrenia. This is supported by the strong genetic association established by genome wide association studies (GWAS) between the human leukocyte antigen (HLA) locus and schizophrenia. HLA proteins (also known in mice as the major histocompatibility complex; MHC) are mediators of the T-lymphocyte responses, and genetic variability is well-established as a risk factor for autoimmune diseases and susceptibility to infectious diseases. Taken together, the findings strongly suggest that schizophrenia risk in a subgroup of patients is caused by an infectious disease, and/or an autoimmune phenomenon. However, this view may be overly simplistic. First, MHC proteins have a non-immune effect on synaptogenesis by modulating synaptic pruning by microglia and other mechanisms, suggesting that genetic variability could be compromising this physiological process. Second, some GWAS signals in the HLA locus map near non-HLA genes, such as the histone gene cluster. On the other hand, recent GWAS data show association signals near B-lymphocyte enhancers, which lend support for an infectious disease etiology. Thus, although the genetic findings implicating the HLA locus are very robust, how genetic variability in this region leads to schizophrenia remains to be elucidated.
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Affiliation(s)
- Ryan Mokhtari
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York, USA
| | - Herbert M Lachman
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York, USA; Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York, USA; Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York, USA; Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York, USA
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Mladinov M, Sedmak G, Fuller HR, Babić Leko M, Mayer D, Kirincich J, Štajduhar A, Borovečki F, Hof PR, Šimić G. Gene expression profiling of the dorsolateral and medial orbitofrontal cortex in schizophrenia. Transl Neurosci 2016; 7:139-150. [PMID: 28123834 PMCID: PMC5234522 DOI: 10.1515/tnsci-2016-0021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/05/2016] [Indexed: 12/29/2022] Open
Abstract
Schizophrenia is a complex polygenic disorder of unknown etiology. Over 3,000 candidate genes associated with schizophrenia have been reported, most of which being mentioned only once. Alterations in cognitive processing - working memory, metacognition and mentalization - represent a core feature of schizophrenia, which indicates the involvement of the prefrontal cortex in the pathophysiology of this disorder. Hence we compared the gene expression in postmortem tissue from the left and right dorsolateral prefrontal cortex (DLPFC, Brodmann's area 46), and the medial part of the orbitofrontal cortex (MOFC, Brodmann's area 11/12), in six patients with schizophrenia and six control brains. Although in the past decade several studies performed transcriptome profiling in schizophrenia, this is the first study to investigate both hemispheres, providing new knowledge about possible brain asymmetry at the level of gene expression and its relation to schizophrenia. We found that in the left hemisphere, twelve genes from the DLPFC and eight genes from the MOFC were differentially expressed in patients with schizophrenia compared to controls. In the right hemisphere there was only one gene differentially expressed in the MOFC. We reproduce the involvement of previously reported genes TARDBP and HNRNPC in the pathogenesis of schizophrenia, and report seven novel genes: SART1, KAT7, C1D, NPM1, EVI2A, XGY2, and TTTY15. As the differentially expressed genes only partially overlap with previous studies that analyzed other brain regions, our findings indicate the importance of considering prefrontal cortical regions, especially those in the left hemisphere, for obtaining disease-relevant insights.
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Affiliation(s)
- Mihovil Mladinov
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia; Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Goran Sedmak
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Heidi R Fuller
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK and Institute for Science and Technology in Medicine, Keele University, Staffordshire, ST5 5BG, United Kingdom of Great Britain and Northern Ireland
| | - Mirjana Babić Leko
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Davor Mayer
- Department of Forensic Medicine, University of Zagreb Medical School, Zagreb, Croatia
| | - Jason Kirincich
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Andrija Štajduhar
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Fran Borovečki
- Department of Neurology, University Clinical Hospital Zagreb, Zagreb, Croatia
| | - Patrick R Hof
- Fishberg Department of Neuroscience, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Goran Šimić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
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Abstract
The etiology and pathophysiology of schizophrenia and related mental disorders such as bipolar disorder and major depression remain largely unclear. Recent advances in mRNA profiling techniques made it possible to perform genome-wide gene expression analysis in a hypothesis-free manner. It was thought that this large-scale data mining approach would reveal unknown molecular cascades involved in mental disorders. Contrary to this initial expectation, however, DNA microarray results in psychiatric fields have been notoriously discordant. Here the authors review the findings of DNA microarray analysis, focusing on systematic gene expression changes in schizophrenia, as well as alterations in the expression of specific genes, that have been reported and replicated. The authors also address the probable causes for the discordance among studies, possible ways to solve the problem, and their preferred approach for data interpretation.
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Affiliation(s)
- Kazuya Iwamoto
- Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Saitama, Japan.
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21
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Freund RK, Graw S, Choo KS, Stevens KE, Leonard S, Dell'Acqua ML. Genetic knockout of the α7 nicotinic acetylcholine receptor gene alters hippocampal long-term potentiation in a background strain-dependent manner. Neurosci Lett 2016; 627:1-6. [PMID: 27233215 DOI: 10.1016/j.neulet.2016.05.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/18/2016] [Accepted: 05/21/2016] [Indexed: 12/01/2022]
Abstract
Reduced α7 nicotinic acetylcholine receptor (nAChR) function is linked to impaired hippocampal-dependent sensory processing and learning and memory in schizophrenia. While knockout of the Chrna7 gene encoding the α7nAChR on a C57/Bl6 background results in changes in cognitive measures, prior studies found little impact on hippocampal synaptic plasticity in these mice. However, schizophrenia is a multi-genic disorder where complex interactions between specific genetic mutations and overall genetic background may play a prominent role in determining phenotypic penetrance. Thus, we compared the consequences of knocking out the α7nAChR on synaptic plasticity in C57/Bl6 and C3H mice, which differ in their basal α7nAChR expression levels. Homozygous α7 deletion in C3H mice, which normally express higher α7nAChR levels, resulted in impaired long-term potentiation (LTP) at hippocampal CA1 synapses, while C3H α7 heterozygous mice maintained robust LTP. In contrast, homozygous α7 deletion in C57 mice, which normally express lower α7nAChR levels, did not alter LTP, as had been previously reported for this strain. Thus, the threshold of Chrna7 expression required for LTP may be different in the two strains. Measurements of auditory gating, a hippocampal-dependent behavioral paradigm used to identify schizophrenia-associated sensory processing deficits, was abnormal in C3H α7 knockout mice confirming that auditory gating also requires α7nAChR expression. Our studies highlight the importance of genetic background on the regulation of synaptic plasticity and could be relevant for understanding genetic and cognitive heterogeneity in human studies of α7nAChR dysfunction in mental disorders.
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Affiliation(s)
- Ronald K Freund
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Sharon Graw
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kevin S Choo
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Karen E Stevens
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Medical Research Service, Veterans Affairs Medical Center, Denver, CO, USA
| | - Sherry Leonard
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Medical Research Service, Veterans Affairs Medical Center, Denver, CO, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Wu JQ, Green MJ, Gardiner EJ, Tooney PA, Scott RJ, Carr VJ, Cairns MJ. Altered neural signaling and immune pathways in peripheral blood mononuclear cells of schizophrenia patients with cognitive impairment: A transcriptome analysis. Brain Behav Immun 2016; 53:194-206. [PMID: 26697997 DOI: 10.1016/j.bbi.2015.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/26/2015] [Accepted: 12/13/2015] [Indexed: 12/20/2022] Open
Abstract
Cognitive deficits are a core feature of schizophrenia and contribute significantly to functional disability. We investigated the molecular pathways associated with schizophrenia (SZ; n=47) cases representing both 'cognitive deficit' (CD; n=22) and 'cognitively spared' (CS; n=25) subtypes of schizophrenia (based on latent class analysis of 9 cognitive performance indicators), compared with 49 healthy controls displaying 'normal' cognition. This was accomplished using gene-set analysis of transcriptome data derived from peripheral blood mononuclear cells (PBMCs). We detected 27 significantly altered pathways (19 pathways up-regulated and 8 down-regulated) in the combined SZ group and a further 6 pathways up-regulated in the CS group and 5 altered pathways (4 down-regulated and 1 up-regulated) in the CD group. The transcriptome profiling in SZ and cognitive subtypes were characterized by the up-regulated pathways involved in immune dysfunction (e.g., antigen presentation in SZ), energy metabolism (e.g., oxidative phosphorylation), and down-regulation of the pathways involved in neuronal signaling (e.g., WNT in SZ/CD and ERBB in SZ). When we looked for pathways that differentiated the two cognitive subtypes we found that the WNT signaling was significantly down-regulated (FDR<0.05) in the CD group in accordance with the combined SZ cohort, whereas it was unaffected in the CS group. This suggested suppression of WNT signaling was a defining feature of cognitive decline in schizophrenia. The WNT pathway plays a role in both the development/function of the central nervous system and peripheral tissues, therefore its alteration in PBMCs may be indicative of an important genomic axis relevant to cognition in the neuropathology of schizophrenia.
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Affiliation(s)
- Jing Qin Wu
- School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Schizophrenia Research Institute, Sydney, Australia; Centre for Translational Neuroscience and Mental Health, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia
| | - Melissa J Green
- Schizophrenia Research Institute, Sydney, Australia; School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - Erin J Gardiner
- School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Schizophrenia Research Institute, Sydney, Australia; Centre for Translational Neuroscience and Mental Health, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia
| | - Paul A Tooney
- School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Schizophrenia Research Institute, Sydney, Australia
| | - Rodney J Scott
- School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Schizophrenia Research Institute, Sydney, Australia; Centre for Translational Neuroscience and Mental Health, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia
| | - Vaughan J Carr
- Schizophrenia Research Institute, Sydney, Australia; School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - Murray J Cairns
- School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Schizophrenia Research Institute, Sydney, Australia; Centre for Translational Neuroscience and Mental Health, Hunter Medical Research Institute, Newcastle, NSW 2305, Australia.
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Association of SNPs in EGR3 and ARC with Schizophrenia Supports a Biological Pathway for Schizophrenia Risk. PLoS One 2015; 10:e0135076. [PMID: 26474411 PMCID: PMC4608790 DOI: 10.1371/journal.pone.0135076] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/17/2015] [Indexed: 02/07/2023] Open
Abstract
We have previously hypothesized a biological pathway of activity-dependent synaptic plasticity proteins that addresses the dual genetic and environmental contributions to schizophrenia. Accordingly, variations in the immediate early gene EGR3, and its target ARC, should influence schizophrenia susceptibility. We used a pooled Next-Generation Sequencing approach to identify variants across these genes in U.S. populations of European (EU) and African (AA) descent. Three EGR3 and one ARC SNP were selected and genotyped for validation, and three SNPs were tested for association in a replication cohort. In the EU group of 386 schizophrenia cases and 150 controls EGR3 SNP rs1877670 and ARC SNP rs35900184 showed significant associations (p = 0.0078 and p = 0.0275, respectively). In the AA group of 185 cases and 50 controls, only the ARC SNP revealed significant association (p = 0.0448). The ARC SNP did not show association in the Han Chinese (CH) population. However, combining the EU, AA, and CH groups revealed a highly significant association of ARC SNP rs35900184 (p = 2.353 x 10−7; OR [95% CI] = 1.54 [1.310–1.820]). These findings support previously reported associations between EGR3 and schizophrenia. Moreover, this is the first report associating an ARC SNP with schizophrenia and supports recent large-scale GWAS findings implicating the ARC complex in schizophrenia risk. These results support the need for further investigation of the proposed pathway of environmentally responsive, synaptic plasticity-related, schizophrenia genes.
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Sinkus ML, Graw S, Freedman R, Ross RG, Lester HA, Leonard S. The human CHRNA7 and CHRFAM7A genes: A review of the genetics, regulation, and function. Neuropharmacology 2015; 96:274-88. [PMID: 25701707 PMCID: PMC4486515 DOI: 10.1016/j.neuropharm.2015.02.006] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 02/04/2015] [Accepted: 02/06/2015] [Indexed: 01/16/2023]
Abstract
The human α7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) is ubiquitously expressed in both the central nervous system and in the periphery. CHRNA7 is genetically linked to multiple disorders with cognitive deficits, including schizophrenia, bipolar disorder, ADHD, epilepsy, Alzheimer's disease, and Rett syndrome. The regulation of CHRNA7 is complex; more than a dozen mechanisms are known, one of which is a partial duplication of the parent gene. Exons 5-10 of CHRNA7 on chromosome 15 were duplicated and inserted 1.6 Mb upstream of CHRNA7, interrupting an earlier partial duplication of two other genes. The chimeric CHRFAM7A gene product, dupα7, assembles with α7 subunits, resulting in a dominant negative regulation of function. The duplication is human specific, occurring neither in primates nor in rodents. The duplicated α7 sequence in exons 5-10 of CHRFAM7A is almost identical to CHRNA7, and thus is not completely queried in high throughput genetic studies (GWAS). Further, pre-clinical animal models of the α7nAChR utilized in drug development research do not have CHRFAM7A (dupα7) and cannot fully model human drug responses. The wide expression of CHRNA7, its multiple functions and modes of regulation present challenges for study of this gene in disease. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.
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Affiliation(s)
- Melissa L Sinkus
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA.
| | - Sharon Graw
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA.
| | - Robert Freedman
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA; Veterans Affairs Medical Research Center, Denver, CO 80262, USA.
| | - Randal G Ross
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA.
| | - Henry A Lester
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Sherry Leonard
- Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA; Veterans Affairs Medical Research Center, Denver, CO 80262, USA.
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Maple AM, Zhao X, Elizalde DI, McBride AK, Gallitano AL. Htr2a Expression Responds Rapidly to Environmental Stimuli in an Egr3-Dependent Manner. ACS Chem Neurosci 2015; 6:1137-42. [PMID: 25857407 DOI: 10.1021/acschemneuro.5b00031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Pharmacologic and genetic findings have implicated the serotonin 2A receptor (5-HT2AR) in the etiology of schizophrenia. Recent studies have shown reduced 5-HT2AR levels in schizophrenia patients, yet the cause of this difference is unknown. Environmental factors, such as stress, also influence schizophrenia risk, yet little is known about how environment may affect this receptor. To determine if acute stress alters 5-HT2AR expression, we examined the effect of sleep deprivation on cortical Htr2a mRNA in mice. We found that 6 h of sleep deprivation induces a twofold increase in Htr2a mRNA, a more rapid effect than has been previously reported. This effect requires the immediate early gene early growth response 3 (Egr3), as sleep deprivation failed to induce Htr2a expression in Egr3-/- mice. These findings provide a functional link between two schizophrenia candidate genes and an explanation of how environment may influence a genetic predisposition for schizophrenia.
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Affiliation(s)
- Amanda M. Maple
- Department of Basic
Medical Sciences, University of Arizona College of Medicine, 425 N. Fifth St., Phoenix, Arizona 85004, United States
| | - Xiuli Zhao
- Department of Basic
Medical Sciences, University of Arizona College of Medicine, 425 N. Fifth St., Phoenix, Arizona 85004, United States
- Interdisciplinary Neuroscience Program, Arizona State University, PO Box 874601, Tempe, Arizona 85287, United States
| | - Diana I. Elizalde
- Department of Basic
Medical Sciences, University of Arizona College of Medicine, 425 N. Fifth St., Phoenix, Arizona 85004, United States
| | - Andrew K. McBride
- Department of Basic
Medical Sciences, University of Arizona College of Medicine, 425 N. Fifth St., Phoenix, Arizona 85004, United States
| | - Amelia L. Gallitano
- Department of Basic
Medical Sciences, University of Arizona College of Medicine, 425 N. Fifth St., Phoenix, Arizona 85004, United States
- Interdisciplinary Neuroscience Program, Arizona State University, PO Box 874601, Tempe, Arizona 85287, United States
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Ma G, Song T, Chen M, Fu Y, Xu Y, Ma E, Wang W, Du J, Huang M. Hippocampal and thalamic neuronal metabolism in a putative rat model of schizophrenia. Neural Regen Res 2014; 8:2415-23. [PMID: 25206551 PMCID: PMC4146111 DOI: 10.3969/j.issn.1673-5374.2013.26.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/01/2013] [Indexed: 12/17/2022] Open
Abstract
The transcription factor early growth response protein 3 (EGR3) is involved in schizophrenia. We developed a putative rat model of schizophrenia by transfecting lentiviral particles carrying the Egr3 gene into bilateral hippocampal dentate gyrus. We assessed spatial working memory using the Morris water maze test, and neuronal metabolite levels in bilateral hippocampus and thalamus were determined by 3.0 T proton magnetic resonance spectroscopy. Choline content was significantly greater in the hippocampus after transfection, while N-acetylaspartate and the ratio of N-acetylaspartate to creatine/phosphocreatine in the thalamus were lower than in controls. This study is the first to report evaluation of brain metabolites using 3.0 T proton magnetic resonance spectroscopy in rats transfected with Egr3, and reveals metabolic abnormalities in the hippocampus and thalamus in this putative model of schizophrenia.
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Affiliation(s)
- Guolin Ma
- Department of Radiology, China-Japan Friendship Hospital, Beijing 100029, China
| | - Tianbin Song
- Department of Radiology, Beijing Shunyi Hospital, Beijing 101300, China
| | - Min Chen
- Department of Radiology, Beijing Hospital Affiliated to the Ministry of Public Health, Beijing 100730, China
| | - Yuan Fu
- Department of Radiology, Beijing Hospital Affiliated to the Ministry of Public Health, Beijing 100730, China
| | - Yong Xu
- Department of Mental Health, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China
| | - Ensen Ma
- Department of Radiology, China-Japan Friendship Hospital, Beijing 100029, China
| | - Wu Wang
- Department of Radiology, China-Japan Friendship Hospital, Beijing 100029, China
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA 92103-8226, USA
| | - Mingxiong Huang
- Radiology Imaging Laboratory, Department of Radiology, University of California, San Diego, CA 92121, USA
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Identification of novel loci for bipolar I disorder in a multi-stage genome-wide association study. Prog Neuropsychopharmacol Biol Psychiatry 2014; 51:58-64. [PMID: 24444492 DOI: 10.1016/j.pnpbp.2014.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/06/2014] [Accepted: 01/07/2014] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Identification of genetic variants that influence bipolar I disorder (BPD-I) through genome-wide association (GWA) studies is limited in Asian populations. The current study aimed to identify novel common variants for BPD-I in an ethnically homogeneous Taiwanese sample using a multi-stage GWA study design. METHOD At the discovery stage, 200 BPD-I patients and 200 controls that combined to form 16 pools were genotyped with 1 million markers. Utilizing a newly developed rank-based method, top-ranked markers were selected. After validation with individual genotyping, a fine-mapping association study was conducted to identify associated loci using 240 patients and 240 controls. At the last stage, independent samples were collected (351 cases and 341 controls) for replication. RESULTS Among the top-ranked markers from the discovery stage, eight genes and 15 individual SNPs were evaluated in the fine-mapping stage. At this stage, rs7619173, which is not in a gene coding region, showed the most significant association (P = 2 ∗ 10(-5)) with BPD-I. Four genes had empirical P-values<0.05, including KCNH7 (P = 0.0047), MYST4 (P = 0.0047), NRXN3 (P = 0.0095), and SEMA3D (P = 0.037). For markers genotyped in replication samples, rs7619173 exhibited a significant association (P(combined) = 2 ∗ 10(-4)) after multiple testing correction, while markers rs11001178 (MYST4) and rs2217887 (NRXN3) showed weak associations (P(combined) = 0.02) with BPD-I. CONCLUSION A multi-stage GWA design has the potential to uncover the underlying pathogenesis of a complex trait. Findings in the present study highlight three loci that warrant further investigation for bipolar.
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Wolock S, Yates A, Petrill SA, Bohland JW, Blair C, Li N, Machiraju R, Huang K, Bartlett CW. Gene × smoking interactions on human brain gene expression: finding common mechanisms in adolescents and adults. J Child Psychol Psychiatry 2013; 54:1109-19. [PMID: 23909413 PMCID: PMC3809890 DOI: 10.1111/jcpp.12119] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/04/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND Numerous studies have examined gene × environment interactions (G × E) in cognitive and behavioral domains. However, these studies have been limited in that they have not been able to directly assess differential patterns of gene expression in the human brain. Here, we assessed G × E interactions using two publically available datasets to assess if DNA variation is associated with post-mortem brain gene expression changes based on smoking behavior, a biobehavioral construct that is part of a complex system of genetic and environmental influences. METHODS We conducted an expression quantitative trait locus (eQTL) study on two independent human brain gene expression datasets assessing G × E for selected psychiatric genes and smoking status. We employed linear regression to model the significance of the Gene × Smoking interaction term, followed by meta-analysis across datasets. RESULTS Overall, we observed that the effect of DNA variation on gene expression is moderated by smoking status. Expression of 16 genes was significantly associated with single nucleotide polymorphisms that demonstrated G × E effects. The strongest finding (p = 1.9 × 10⁻¹¹) was neurexin 3-alpha (NRXN3), a synaptic cell-cell adhesion molecule involved in maintenance of neural connections (such as the maintenance of smoking behavior). Other significant G × E associations include four glutamate genes. CONCLUSIONS This is one of the first studies to demonstrate G × E effects within the human brain. In particular, this study implicated NRXN3 in the maintenance of smoking. The effect of smoking on NRXN3 expression and downstream behavior is different based upon SNP genotype, indicating that DNA profiles based on SNPs could be useful in understanding the effects of smoking behaviors. These results suggest that better measurement of psychiatric conditions, and the environment in post-mortem brain studies may yield an important avenue for understanding the biological mechanisms of G × E interactions in psychiatry.
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Affiliation(s)
- Samuel Wolock
- Battelle Center for Mathematical Medicine, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Andrew Yates
- Department of Biomedical Informatics, The Ohio State University College of Medicine, Columbus, OH, USA
| | | | - Jason W. Bohland
- Department of Health Sciences, Boston University, Boston, MA, USA
| | - Clancy Blair
- Department of Applied Psychology, New York University, New York, NY, USA
| | - Ning Li
- Battelle Center for Mathematical Medicine, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Raghu Machiraju
- Department of Biomedical Informatics, The Ohio State University College of Medicine, Columbus, OH, USA
,Department of Computer Science and Engineering, The Ohio State University, Columbus, OH, USA
| | - Kun Huang
- Department of Biomedical Informatics, The Ohio State University College of Medicine, Columbus, OH, USA
,Department of Computer Science and Engineering, The Ohio State University, Columbus, OH, USA
,The CCC Biomedical Informatics Shared Resource, The Ohio State University Columbus, OH, USA
| | - Christopher W. Bartlett
- Battelle Center for Mathematical Medicine, Nationwide Children’s Hospital, Columbus, OH, USA
,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
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Expression of immune genes on chromosome 6p21.3-22.1 in schizophrenia. Brain Behav Immun 2013; 32:51-62. [PMID: 23395714 PMCID: PMC3686871 DOI: 10.1016/j.bbi.2013.01.087] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 01/14/2013] [Accepted: 01/30/2013] [Indexed: 11/24/2022] Open
Abstract
Schizophrenia is a common mental illness with a large genetic component. Three genome-wide association studies have implicated the major histocompatibility complex gene region on chromosome 6p21.3-22.1 in schizophrenia. In addition, nicotine, which is commonly abused in schizophrenia, affects the expression of central nervous system immune genes. Messenger RNA levels for genes in the 6p21.3-22.1 region were measured in human postmortem hippocampus of 89 subjects. The effects of schizophrenia diagnosis, smoking and systemic inflammatory illness were compared. Cell-specific expression patterns for the class I major histocompatibility complex gene HLA-A were explored utilizing in situ hybridization. Expression of five genes was altered in schizophrenic subjects. Messenger RNA levels for the class I major histocompatibility complex antigen HLA-B were increased in schizophrenic nonsmokers, while levels for smokers were indistinguishable from those of controls. β2 microglobulin, HLA-A and Notch4 were all expressed in a pattern where inflammatory illness was associated with increased expression in controls but not in subjects with schizophrenia. Schizophrenia was also associated with increased expression of Butyrophilin 2A2. HLA-A was expressed in glutamatergic and GABAergic neurons in the dentate gyrus, hilus, and the stratum pyramidale of the CA1-CA4 regions of the hippocampus, but not in astrocytes. In conclusion, the expression of genes from the major histocompatibility complex region of chromosome 6 with likely roles in synaptic development is altered in schizophrenia. There were also significant interactions between schizophrenia diagnosis and both inflammatory illness and smoking.
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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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31
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Abstract
Schizophrenia is a severe neuropsychiatric disorder without adequate current treatment. Recent theories of schizophrenia focus on disturbances of glutamatergic neurotransmission particularly at N-methyl-D-aspartate (NMDA)-type glutamate receptors. NMDA receptors are regulated in vivo by the amino acids glycine and D-serine. Glycine levels, in turn, are regulated by glycine type I (GlyT1) transporters, which serve to maintain low subsaturating glycine levels in the vicinity of the NMDA receptor. A proposed approach to treatment of schizophrenia, therefore, is inhibition of GlyT1-mediated transport. Over the past decade, several well tolerated, high affinity GlyT1 inhibitors have been developed and shown to potentiate NMDA receptor-mediated neurotransmission in animal models relevant to schizophrenia. In addition, clinical trials have been conducted with sarcosine (N-methylglycine), a naturally occurring GlyT1 inhibitor, and with the high affinity compound RG1678. Although definitive trials remain ongoing, encouraging results to date have been reported.
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Affiliation(s)
- Daniel C Javitt
- Nathan S Kline Institute for Psychiatric Research, Columbia University, Orangeburg, NY 10962, USA.
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32
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Williams AA, Ingram WM, Levine S, Resnik J, Kamel CM, Lish JR, Elizalde DI, Janowski SA, Shoker J, Kozlenkov A, González-Maeso J, Gallitano AL. Reduced levels of serotonin 2A receptors underlie resistance of Egr3-deficient mice to locomotor suppression by clozapine. Neuropsychopharmacology 2012; 37:2285-98. [PMID: 22692564 PMCID: PMC3422493 DOI: 10.1038/npp.2012.81] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/06/2012] [Accepted: 04/26/2012] [Indexed: 02/06/2023]
Abstract
The immediate-early gene early growth response 3 (Egr3) is associated with schizophrenia and expressed at reduced levels in postmortem patients' brains. We have previously reported that Egr3-deficient (Egr3(-/-)) mice display reduced sensitivity to the sedating effects of clozapine compared with wild-type (WT) littermates, paralleling the heightened tolerance of schizophrenia patients to antipsychotic side effects. In this study, we have used a pharmacological dissection approach to identify a neurotransmitter receptor defect in Egr3(-/-) mice that may mediate their resistance to the locomotor suppressive effects of clozapine. We report that this response is specific to second-generation antipsychotic agents (SGAs), as first-generation medications suppress the locomotor activity of Egr3(-/-) and WT mice to a similar degree. Further, in contrast to the leading theory that sedation by clozapine results from anti-histaminergic effects, we show that H1 histamine receptors are not responsible for this effect in C57BL/6 mice. Instead, selective serotonin 2A receptor (5HT(2A)R) antagonists ketanserin and MDL-11939 replicate the effect of SGAs, repressing the activity in WT mice at a dosage that fails to suppress the activity of Egr3(-/-) mice. Radioligand binding revealed nearly 70% reduction in 5HT(2A)R expression in the prefrontal cortex of Egr3(-/-) mice compared with controls. Egr3(-/-) mice also exhibit a decreased head-twitch response to 5HT(2A)R agonist 1-(2,5-dimethoxy 4-iodophenyl)-2-amino propane (DOI). These findings provide a mechanism to explain the reduced sensitivity of Egr3(-/-) mice to the locomotor suppressive effects of SGAs, and suggest that 5HT(2A)Rs may also contribute to the sedating properties of these medications in humans. Moreover, as the deficit in cortical 5HT(2A)R in Egr3(-/-) mice aligns with numerous studies reporting decreased 5HT(2A)R levels in the brains of schizophrenia patients, and the gene encoding the 5HT(2A)R is itself a leading schizophrenia candidate gene, these findings suggest a potential mechanism by which putative dysfunction in EGR3 in humans may influence risk for schizophrenia.
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Affiliation(s)
| | - Wendy M Ingram
- Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley, CA, USA
| | - Sarah Levine
- University of Arizona College of Medicine—Tucson, Tucson, AZ, USA
| | - Jack Resnik
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Christy M Kamel
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - James R Lish
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Diana I Elizalde
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Scott A Janowski
- University of Arizona College of Medicine—Tucson, Tucson, AZ, USA
| | - Joseph Shoker
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Alexey Kozlenkov
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
| | - Javier González-Maeso
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Amelia L Gallitano
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
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Family-based association study of early growth response gene 3 with child bipolar I disorder. J Affect Disord 2012; 138:387-96. [PMID: 22370066 PMCID: PMC3349283 DOI: 10.1016/j.jad.2012.01.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 01/04/2012] [Indexed: 01/02/2023]
Abstract
BACKGROUND The risk for relapse of child bipolar I disorder (BP-I) is highly correlated with environmental factors. Immediate early genes of the early growth response (EGR) gene family are activated at high levels in the brain in response to environmental events, including stress, and mediate numerous neurobiological processes that have been associated with mental illness risk. The objective of this study is to evaluate whether single nucleotide polymorphisms (SNPs) in EGR genes are associated with the risk to develop child bipolar I disorder. METHODS To investigate whether EGR genes may influence susceptibility to child bipolar I disorder (BP-I), we used Family Based Association Tests to examine whether SNPs in each of the EGR genes were associated with illness in 49 families. RESULTS Two SNPs in EGR3 displayed nominally significant associations with child BP-I (p=0.027 and p=0.028); though neither was statistically significant following correction for multiple comparisons. Haplotype association analysis indicated that these SNPs are in linkage disequilibrium (LD). None of the SNPs tested in EGR1, EGR2, or EGR4 was associated with child BP-I. LIMITATIONS This study was limited by small sample size, which resulted in it being underpowered to detect a significant association after correction for multiple comparisons. CONCLUSIONS Our study revealed a preliminary finding suggesting that EGR3, a gene that translates environmental stimuli into long-term changes in the brain, warrants further investigation for association with risk for child BP-I disorder in a larger sample. Such studies may help reveal mechanisms by which environment can interact with genetic predisposition to influence this severe mental illness.
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Catts VS, Weickert CS. Gene expression analysis implicates a death receptor pathway in schizophrenia pathology. PLoS One 2012; 7:e35511. [PMID: 22545112 PMCID: PMC3335850 DOI: 10.1371/journal.pone.0035511] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 03/16/2012] [Indexed: 12/22/2022] Open
Abstract
An increase in apoptotic events may underlie neuropathology in schizophrenia. By data-mining approaches, we identified significant expression changes in death receptor signaling pathways in the dorsolateral prefrontal cortex (DLPFC) of patients with schizophrenia, particularly implicating the Tumor Necrosis Factor Superfamily member 6 (FAS) receptor and the Tumor Necrosis Factor [ligand] Superfamily member 13 (TNFSF13) in schizophrenia. We sought to confirm and replicate in an independent tissue collection the noted mRNA changes with quantitative real-time RT-PCR. To test for regional and diagnostic specificity, tissue from orbital frontal cortex (OFC) was examined and a bipolar disorder group included. In schizophrenia, we confirmed and replicated significantly increased expression of TNFSF13 mRNA in the DLPFC. Also, a significantly larger proportion of subjects in the schizophrenia group had elevated FAS receptor expression in the DLPFC relative to unaffected controls. These changes were not observed in the bipolar disorder group. In the OFC, there were no significant differences in TNFSF13 or FAS receptor mRNA expression. Decreases in BH3 interacting domain death agonist (BID) mRNA transcript levels were found in the schizophrenia and bipolar disorder groups affecting both the DLPFC and the OFC. We tested if TNFSF13 mRNA expression correlated with neuronal mRNAs in the DLPFC, and found significant negative correlations with interneuron markers, parvalbumin and somatostatin, and a positive correlation with PPP1R9B (spinophilin), but not DLG4 (PSD-95). The expression of TNFSF13 mRNA in DLPFC correlated negatively with tissue pH, but decreasing pH in cultured cells did not cause increased TNFSF13 mRNA nor did exogenous TNFSF13 decrease pH. We concluded that increased TNFSF13 expression may be one of several cell-death cytokine abnormalities that contribute to the observed brain pathology in schizophrenia, and while increased TNFSF13 may be associated with lower brain pH, the change is not necessarily causally related to brain pH.
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Affiliation(s)
- Vibeke Sørensen Catts
- Schizophrenia Research Laboratory, Schizophrenia Research Institute, Sydney, New South Wales, Australia.
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35
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Stephens SH, Franks A, Berger R, Palionyte M, Fingerlin TE, Wagner B, Logel J, Olincy A, Ross RG, Freedman R, Leonard S. Multiple genes in the 15q13-q14 chromosomal region are associated with schizophrenia. Psychiatr Genet 2012; 22:1-14. [PMID: 21970977 PMCID: PMC3878876 DOI: 10.1097/ypg.0b013e32834c0c33] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The chromosomal region, 15q13-q14, including the α7 nicotinic acetylcholine receptor gene, CHRNA7, is a replicated region for schizophrenia. This study fine-mapped genes at 15q13-q14 to determine whether the association is unique to CHRNA7. METHODS Family-based and case-control association studies were performed on Caucasian-non-Hispanic and African-American individuals from 120 families as well as 468 individual patients with schizophrenia and 144 well-characterized controls. Single-nucleotide polymorphism (SNP) markers were genotyped, and association analyses carried out for the outcomes of schizophrenia, smoking, and smoking in schizophrenia. RESULTS Three genes were associated with schizophrenia in both ethnic populations: TRPM1, KLF13, and RYR3. Two SNPs in CHRNA7 were associated with schizophrenia in African-Americans, and a second SNP in CHRNA7 was significant for an association with smoking and smoking in schizophrenia in Caucasians. CONCLUSION Results of these studies support association of the 15q13-q14 region with schizophrenia. The broad positive association suggests that more than one 15q gene may be contributing to the disorder, either in combination or through a regulatory mechanism.
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Affiliation(s)
- Sarah H. Stephens
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
| | - Alexis Franks
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
| | - Ralph Berger
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
| | - Milda Palionyte
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
| | - Tasha E. Fingerlin
- Preventive Medicine and Biometrics, University of Colorado Denver, Denver, Colorado, USA
| | - Brandie Wagner
- Preventive Medicine and Biometrics, University of Colorado Denver, Denver, Colorado, USA
| | - Judith Logel
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
| | - Ann Olincy
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
| | - Randal G. Ross
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
| | - Robert Freedman
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
- Veterans Affairs Medical Research Center, Denver, Colorado, USA
| | - Sherry Leonard
- Department of Psychiatry, University of Colorado Denver, Denver, Colorado, USA
- Veterans Affairs Medical Research Center, Denver, Colorado, USA
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Zhang R, Lu S, Meng L, Min Z, Tian J, Valenzuela RK, Guo T, Tian L, Zhao W, Ma J. Genetic evidence for the association between the early growth response 3 (EGR3) gene and schizophrenia. PLoS One 2012; 7:e30237. [PMID: 22276163 PMCID: PMC3262808 DOI: 10.1371/journal.pone.0030237] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 12/16/2011] [Indexed: 01/26/2023] Open
Abstract
Recently, two genome scan meta-analysis studies have found strong evidence for the association of loci on chromosome 8p with schizophrenia. The early growth response 3 (EGR3) gene located in chromosome 8p21.3 was also found to be involved in the etiology of schizophrenia. However, subsequent studies failed to replicate this finding. To investigate the genetic role of EGR3 in Chinese patients, we genotyped four SNPs (average interval ∼2.3 kb) in the chromosome region of EGR3 in 470 Chinese schizophrenia patients and 480 healthy control subjects. The SNP rs35201266 (located in intron 1 of EGR3) showed significant differences between cases and controls in both genotype frequency distribution (P = 0.016) and allele frequency distribution (P = 0.009). Analysis of the haplotype rs35201266-rs3750192 provided significant evidence for association with schizophrenia (P = 0.0012); a significant difference was found for the common haplotype AG (P = 0.0005). Furthermore, significant associations were also found in several other two-, and three-SNP tests of haplotype analyses. The meta-analysis revealed a statistically significant association between rs35201266 and schizophrenia (P = 0.0001). In summary, our study supports the association of EGR3 with schizophrenia in our Han Chinese sample, and further functional exploration of the EGR3 gene will contribute to the molecular basis for the complex network underlying schizophrenia pathogenesis.
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Affiliation(s)
- Rui Zhang
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Shemin Lu
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Liesu Meng
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Zixin Min
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Juan Tian
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Robert K. Valenzuela
- Arizona Health Science Center, University of Arizona, Tucson, Arizona, United States of America
| | - Tingwei Guo
- Albert Einstein College of Medicine, New York, New York, United States of America
| | - Lifang Tian
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Wenxiang Zhao
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Jie Ma
- Department of Genetics and Molecular Biology, and Department of Epidemiology and Health Statistics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
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Kano SI, Nwulia E, Niwa M, Chen Y, Sawa A, Cascella N. Altered MHC class I expression in dorsolateral prefrontal cortex of nonsmoker patients with schizophrenia. Neurosci Res 2011; 71:289-93. [DOI: 10.1016/j.neures.2011.07.1818] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/28/2011] [Accepted: 07/11/2011] [Indexed: 10/17/2022]
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Araud T, Graw S, Berger R, Lee M, Neveu E, Bertrand D, Leonard S. The chimeric gene CHRFAM7A, a partial duplication of the CHRNA7 gene, is a dominant negative regulator of α7*nAChR function. Biochem Pharmacol 2011; 82:904-14. [PMID: 21718690 PMCID: PMC3162115 DOI: 10.1016/j.bcp.2011.06.018] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 06/10/2011] [Accepted: 06/13/2011] [Indexed: 12/11/2022]
Abstract
The human α7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) is a candidate gene for schizophrenia and an important drug target for cognitive deficits in the disorder. Activation of the α7*nAChR, results in opening of the channel and entry of mono- and divalent cations, including Ca(2+), that presynaptically participates to neurotransmitter release and postsynaptically to down-stream changes in gene expression. Schizophrenic patients have low levels of α7*nAChR, as measured by binding of the ligand [(125)I]-α-bungarotoxin (I-BTX). The structure of the gene, CHRNA7, is complex. During evolution, CHRNA7 was partially duplicated as a chimeric gene (CHRFAM7A), which is expressed in the human brain and elsewhere in the body. The association between a 2bp deletion in CHRFAM7A and schizophrenia suggested that this duplicate gene might contribute to cognitive impairment. To examine the putative contribution of CHRFAM7A on receptor function, co-expression of α7 and the duplicate genes was carried out in cell lines and Xenopus oocytes. Expression of the duplicate alone yielded protein expression but no functional receptor and co-expression with α7 caused a significant reduction of the amplitude of the ACh-evoked currents. Reduced current amplitude was not correlated with a reduction of I-BTX binding, suggesting the presence of non-functional (ACh-silent) receptors. This hypothesis is supported by a larger increase of the ACh-evoked current by the allosteric modulator 1-(5-chloro-2,4-dimethoxy-phenyl)-3-(5-methyl-isoxazol-3-yl)-urea (PNU-120596) in cells expressing the duplicate than in the control. These results suggest that CHRFAM7A acts as a dominant negative modulator of CHRNA7 function and is critical for receptor regulation in humans.
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Affiliation(s)
- Tanguy Araud
- Department of Neurosciences Medical Faculty, University of Geneva, Geneva, Switzerland.
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Sodhi MS, Simmons M, McCullumsmith R, Haroutunian V, Meador-Woodruff JH. Glutamatergic gene expression is specifically reduced in thalamocortical projecting relay neurons in schizophrenia. Biol Psychiatry 2011; 70:646-54. [PMID: 21549355 PMCID: PMC3176961 DOI: 10.1016/j.biopsych.2011.02.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 01/28/2011] [Accepted: 02/22/2011] [Indexed: 11/28/2022]
Abstract
BACKGROUND Impairment of glutamate neurons that relay sensory and cognitive information from the medial dorsal thalamus to the dorsolateral prefrontal cortex and other cortical regions may contribute to the pathophysiology of schizophrenia. In this study, we have assessed the cell-specific expression of glutamatergic transcripts in the medial dorsal thalamus. METHODS We used laser capture microdissection to harvest two populations of medial dorsal thalamic cells, one enriched with glutamatergic relay neurons and the other with gamma-aminobutyric acidergic neurons and astroglia, from postmortem brains of subjects with schizophrenia (n = 14) and a comparison group (n = 20). Quantitative polymerase chain reaction of extracted RNA was used to assay gene expression in the different cell populations. RESULTS The transcripts encoding the ionotropic glutamate receptor subunits NR2D, GluR3, GluR6, GluR7, and the intracellular proteins GRIP1 and SynGAP1 were significantly decreased in relay neurons but not in the mixed glial and interneuron population in schizophrenia. CONCLUSIONS Our data suggest that reduced ionotropic glutamatergic expression occurs selectively in neurons, which give rise to the cortical projections of the medial dorsal thalamus in schizophrenia, rather than in thalamic cells that function locally. Our findings indicate that glutamatergic innervation is dysfunctional in the circuitry between the medial dorsal thalamus and cortex.
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Affiliation(s)
- Monsheel S. Sodhi
- Dept. Psychiatry and Behavioral Neurobiology, UAB, 1720 7 Avenue Sth. Birmingham, Alabama 35294-0019, USA,Dept. Pharmacy Practice and Center for Pharmaceutical Biotechnology, College of Pharmacy, 900 S Ashland Ave, Chicago, Illinois 60607-4067, USA,Correspondence should be addressed to: Monsheel Sodhi Ph.D., 900 S. Ashland Ave. Chicago IL 60607-4067, USA, Tel: +1-312-355-5949, Fax: +1-312-413-9303,
| | - Micah Simmons
- Dept. Psychiatry and Behavioral Neurobiology, UAB, 1720 7 Avenue Sth. Birmingham, Alabama 35294-0019, USA
| | - Robert McCullumsmith
- Dept. Psychiatry and Behavioral Neurobiology, UAB, 1720 7 Avenue Sth. Birmingham, Alabama 35294-0019, USA
| | - Vahram Haroutunian
- Dept. Psychiatry, The Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, New York 10029-6574, USA
| | - James H. Meador-Woodruff
- Dept. Psychiatry and Behavioral Neurobiology, UAB, 1720 7 Avenue Sth. Birmingham, Alabama 35294-0019, USA
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Wonodi I, Stine OC, Sathyasaikumar KV, Roberts RC, Mitchell BD, Hong LE, Kajii Y, Thaker GK, Schwarcz R. Downregulated kynurenine 3-monooxygenase gene expression and enzyme activity in schizophrenia and genetic association with schizophrenia endophenotypes. ACTA ACUST UNITED AC 2011; 68:665-74. [PMID: 21727251 DOI: 10.1001/archgenpsychiatry.2011.71] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Kynurenic acid, a metabolite of the kynurenine pathway of tryptophan degradation, is an antagonist at N-methyl-d-aspartate and α7 nicotinic acetylcholine receptors and modulates glutamate, dopamine, and acetylcholine signaling. Cortical kynurenic acid concentrations are elevated in the brain and cerebrospinal fluid of schizophrenia patients. The proximal cause may be an impairment of kynurenine 3-monooxygenase (KMO), a rate-limiting enzyme at the branching point of the kynurenine pathway. OBJECTIVES To examine KMO messenger RNA expression and KMO enzyme activity in postmortem tissue from the frontal eye field (FEF; Brodmann area 6) obtained from schizophrenia individuals compared with healthy control individuals and to explore the relationship between KMO single-nucleotide polymorphisms and schizophrenia oculomotor endophenotypes. DESIGN Case-control postmortem and clinical study. SETTING Maryland Brain Collection, outpatient clinics. PARTICIPANTS Postmortem specimens from schizophrenia patients (n = 32) and control donors (n = 32) and a clinical sample of schizophrenia patients (n = 248) and healthy controls (n = 228). MAIN OUTCOME MEASURES Comparison of quantitative KMO messenger RNA expression and KMO enzyme activity in postmortem FEF tissue between schizophrenia patients and controls and association of KMO single-nucleotide polymorphisms with messenger RNA expression in postmortem FEF and schizophrenia and oculomotor endophenotypes (ie, smooth pursuit eye movements and oculomotor delayed response). RESULTS In postmortem tissue, we found a significant and correlated reduction in KMO gene expression and KMO enzyme activity in the FEF in schizophrenia patients. In the clinical sample, KMO rs2275163 was not associated with a diagnosis of schizophrenia but showed modest effects on predictive pursuit and visuospatial working memory endophenotypes. CONCLUSION Our results provide converging lines of evidence implicating reduced KMO activity in the etiopathophysiology of schizophrenia and related neurocognitive deficits.
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Affiliation(s)
- Ikwunga Wonodi
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228.
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Lin CY, Sawa A, Jaaro-Peled H. Better understanding of mechanisms of schizophrenia and bipolar disorder: from human gene expression profiles to mouse models. Neurobiol Dis 2011; 45:48-56. [PMID: 21914480 DOI: 10.1016/j.nbd.2011.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/22/2011] [Accepted: 08/26/2011] [Indexed: 01/01/2023] Open
Abstract
The molecular mechanisms of major mental illnesses, such as schizophrenia and bipolar disorder, are unclear. To address this fundamental question, many groups have studied molecular expression profiles in postmortem brains and other tissues from patients compared with those from normal controls. Development of unbiased high-throughput approaches, such as microarray, RNA-seq, and proteomics, have supported and facilitated this endeavor. In addition to genes directly involved in neuron/glia signaling, especially those encoding for synaptic proteins, genes for metabolic cascades are differentially expressed in the brains of patients with schizophrenia and bipolar disorder, compared with those from normal controls in DNA microarray studies. Here we propose the importance and usefulness of genetic mouse models in which such differentially expressed molecules are modulated. These animal models allow us to dissect the mechanisms of how such molecular changes in patient brains may play a role in neuronal circuitries and overall behavioral phenotypes. We also point out that models in which the metabolic genes are modified are obviously untested from mental illness viewpoints, suggesting the potential to re-address these models with behavioral assays and neurochemical assessments.
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Affiliation(s)
- Chi-Ying Lin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Knott VJ, Millar AM, McIntosh JF, Shah DK, Fisher DJ, Blais CM, Ilivitsky V, Horn E. Separate and combined effects of low dose ketamine and nicotine on behavioural and neural correlates of sustained attention. Biol Psychol 2011; 88:83-93. [PMID: 21742012 DOI: 10.1016/j.biopsycho.2011.06.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 06/21/2011] [Accepted: 06/24/2011] [Indexed: 01/08/2023]
Abstract
Given the cognitive-promoting properties of the nicotinic acetylcholinergic receptor (nAChR) agonist, nicotine, the increased prevalence of smoke-inhaled nicotine in schizophrenia has been interpreted as an attempt to self-correct cognitive deficits, which have been particularly pronounced in the attentional domain. As glutamatergic abnormalities have been implicated in these attentional deficiencies, this study attempted to shed light on the separate and interactive roles of the N-methyl-d-aspartate receptor (NMDAR) and nAChR systems in the modulation of attention by investigating, in healthy volunteers, the separate and combined effects of nicotine and the NMDAR antagonist ketamine on neural and behavioural responses in a sustained attention task. In a randomized, double-blind, placebo controlled study, performance and the P300 event-related brain potential (ERP) in a visual information processing (RVIP) task were examined in 20 smokers and 20 non-smokers (both male and female). Assessment involved intravenous injection of a low subperceptual bolus dose (.04mg/kg) of ketamine or placebo, which was accompanied by acute treatment with nicotine (4mg) or placebo gum. Nicotine-enhanced attentional processing was most evident in nonsmokers, with both performance accuracy and P300 amplitude measures. Ketamine's detrimental effects on these behavioural and electrophysiologic measures were negatively moderated by acute nicotine, the synergistic effects being expressed differently in smokers and nonsmokers. These findings support the view that acute alterations and individual differences in nAChR function can moderate even subtle glutamatergic-driven cognitive deficiencies in schizophrenia and can be important therapeutic targets for treating cognitive impairments in schizophrenia.
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Affiliation(s)
- Verner J Knott
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.
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Sequeira PA, Martin MV, Vawter MP. The first decade and beyond of transcriptional profiling in schizophrenia. Neurobiol Dis 2011; 45:23-36. [PMID: 21396449 DOI: 10.1016/j.nbd.2011.03.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 02/28/2011] [Accepted: 03/02/2011] [Indexed: 01/19/2023] Open
Abstract
Gene expression changes in brains of individuals with schizophrenia (SZ) have been hypothesized to reflect possible pathways related to pathophysiology and/or medication. Other factors having robust effects on gene expression profiling in brain and possibly influence the schizophrenia transcriptome such as age and pH are examined. Pathways of curated gene expression or gene correlation networks reported in SZ (white matter, apoptosis, neurogenesis, synaptic plasticity, glutamatergic and GABAergic neurotransmission, immune and stress-response, mitochondrial, and neurodevelopment) are not unique to SZ and have been associated with other psychiatric disorders. Suggestions going forward to improve the next decade of profiling: consider multiple brain regions that are carefully dissected, release large datasets from multiple brain regions in controls to better understand neurocircuitry, integrate genetics and gene expression, measure expression variants on genome wide level, peripheral biomarker studies, and analyze the transcriptome across a developmental series of brains. Gene expression, while an important feature of the genomic landscape, requires further systems biology to advance from control brains to a more precise definition of the schizophrenia interactome.
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Affiliation(s)
- P Adolfo Sequeira
- Functional Genomics Laboratory, Department of Psychiatry and Human Behavior, School of Medicine, University of California, Irvine, Irvine, CA 92697-4260, USA
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Udawela M, Scarr E, Hannan AJ, Thomas EA, Dean B. Phospholipase C beta 1 expression in the dorsolateral prefrontal cortex from patients with schizophrenia at different stages of illness. Aust N Z J Psychiatry 2011; 45:140-7. [PMID: 21091263 DOI: 10.3109/00048674.2010.533364] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Our recent microarray study detected decreases in the expression of phospholipase C beta 1 mRNA in the dorsolateral prefrontal cortex from subjects with schizophrenia at different stages of illness. Thus we aimed to validate and extend these findings. METHOD We measured levels of mRNA and protein for phospholipase C beta 1 variant a and b using real-time PCR and western blot analysis, respectively, in the dorsolateral prefrontal cortex from subjects with schizophrenia, who had a short (< 7 years) or long (> 22 years) duration of illness. RESULTS Compared to age/sex matched controls, levels of phospholipase C beta 1 variant a and b mRNAs were decreased (-33% and -50%, respectively) in short duration schizophrenia. By contrast, only variant a mRNA was decreased (-24%) in long duration schizophrenia. There was no significant difference in the protein levels of either phospholipase C beta 1 variant in schizophrenia, irrespective of duration of illness (variant a; P = 0.84, variant b; P = 0.73). CONCLUSION Our data confirm that phospholipase C beta 1 transcript levels are decreased in the dorsolateral prefrontal cortex from subjects with schizophrenia. However, the changes in levels of mRNA do not translate into a change at the level of protein. It is possible protein expression is regulated independently of mRNA and it remains to be determined whether there is a functional consequence of this change in mRNA relating to the pathophysiology of schizophrenia.
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Affiliation(s)
- Madhara Udawela
- Rebecca L. Cooper Research Laboratories, Mental Health Research Institute, Parkville, Victoria, Australia.
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Wang J, Cui W, Wei J, Sun D, Gutala R, Gu J, Li MD. Genome-wide expression analysis reveals diverse effects of acute nicotine exposure on neuronal function-related genes and pathways. Front Psychiatry 2011; 2:5. [PMID: 21556275 PMCID: PMC3089989 DOI: 10.3389/fpsyt.2011.00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 02/16/2011] [Indexed: 12/04/2022] Open
Abstract
Previous human and animal studies demonstrate that acute nicotine exposure has complicated influences on the function of the nervous system, which may lead to long-lasting effects on the behavior and physiology of the subject. To determine the genes and pathways that might account for long-term changes after acute nicotine exposure, a pathway-focused oligoarray specifically designed for drug addiction research was used to assess acute nicotine effect on gene expression in the neuron-like SH-SY5Y cells. Our results showed that 295 genes involved in various biological functions were differentially regulated by 1 h of nicotine treatment. Among these genes, the expression changes of 221 were blocked by mecamylamine, indicating that the majority of nicotine-modulated genes were altered through the nicotinic acetylcholine receptors (nAChRs)-mediated signaling process. We further identified 14 biochemical pathways enriched among the nicotine-modulated genes, among which were those involved in neural development/synaptic plasticity, neuronal survival/death, immune response, or cellular metabolism. In the genes significantly regulated by nicotine but blocked by mecamylamine, 13 enriched pathways were detected. Nine of these pathways were shared with those enriched in the genes regulated by nicotine, including neuronal function-related pathways such as glucocorticoid receptor signaling, p38 MAPK signaling, PI3K/AKT signaling, and PTEN signaling, implying that nAChRs play important roles in the regulation of these biological processes. Together, our results not only provide insights into the mechanism underlying the acute response of neuronal cells to nicotine but also provide clues to how acute nicotine exposure exerts long-term effects on the nervous system.
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Affiliation(s)
- Ju Wang
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia Charlottesville, VA, USA
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Kim SH, Song JY, Joo EJ, Lee KY, Ahn YM, Kim YS. EGR3 as a potential susceptibility gene for schizophrenia in Korea. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:1355-60. [PMID: 20687139 DOI: 10.1002/ajmg.b.31115] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Early growth response (EGR) genes play critical roles in signal transduction in the brain, which is involved in neuronal activation, brain development, and synaptic plasticity. EGR genes, including EGR2, EGR3, and EGR4, showed significant association with schizophrenia in Japanese schizophrenic pedigrees. In particular, EGR3, which resides at the chromosomal location 8p21.3, was suggested to be a potential susceptibility gene in schizophrenia based on a study of Japanese cases. However, this requires further replication with an independent sample set. We investigated the association of the EGR3 and EGR2 genes, which were suggested as potential susceptibility genes for schizophrenia supported by both genetic association and postmortem brain expression studies, with schizophrenia in Korean patients. Along with 350 healthy individuals, 244 schizophrenic patients were analyzed. Among the four examined single-nucleotide polymorphisms (SNPs) of EGR3 (rs1008949, rs7009708, rs35201266, and rs3750192), SNP rs35201266 in intron 1 of the EGR3 gene showed a significant association with schizophrenia (P = 0.0008, χ(2) = 11.156, OR = 1.493), which withstands multiple testing correction. In addition, the "T-G-C-G" haplotype of EGR3 was under-represented in the patients with schizophrenia (P = 0.0073, χ(2) = 7.188, OR = 0.697). However, an association between the SNPs of EGR2 (rs2295814 and rs2297488) and schizophrenia was not found. These findings are consistent with the previous genetic association of the EGR3 gene in Japanese cohorts, which is the first replication concerning the association of EGR3 with schizophrenia in an independent cohort. Taken together, EGR3 could be suggested as a compelling susceptibility gene in schizophrenia.
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Affiliation(s)
- Se Hyun Kim
- Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, Seoul, Republic of Korea
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Guo AY, Sun J, Jia P, Zhao Z. A novel microRNA and transcription factor mediated regulatory network in schizophrenia. BMC SYSTEMS BIOLOGY 2010; 4:10. [PMID: 20156358 PMCID: PMC2834616 DOI: 10.1186/1752-0509-4-10] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 02/15/2010] [Indexed: 01/02/2023]
Abstract
Background Schizophrenia is a complex brain disorder with molecular mechanisms that have yet to be elucidated. Previous studies have suggested that changes in gene expression may play an important role in the etiology of schizophrenia, and that microRNAs (miRNAs) and transcription factors (TFs) are primary regulators of this gene expression. So far, several miRNA-TF mediated regulatory modules have been verified. We hypothesized that miRNAs and TFs might play combinatory regulatory roles for schizophrenia genes and, thus, explored miRNA-TF regulatory networks in schizophrenia. Results We identified 32 feed-forward loops (FFLs) among our compiled schizophrenia-related miRNAs, TFs and genes. Our evaluation revealed that these observed FFLs were significantly enriched in schizophrenia genes. By converging the FFLs and mutual feedback loops, we constructed a novel miRNA-TF regulatory network for schizophrenia. Our analysis revealed EGR3 and hsa-miR-195 were core regulators in this regulatory network. We next proposed a model highlighting EGR3 and miRNAs involved in signaling pathways and regulatory networks in the nervous system. Finally, we suggested several single nucleotide polymorphisms (SNPs) located on miRNAs, their target sites, and TFBSs, which may have an effect in schizophrenia gene regulation. Conclusions This study provides many insights on the regulatory mechanisms of genes involved in schizophrenia. It represents the first investigation of a miRNA-TF regulatory network for a complex disease, as demonstrated in schizophrenia.
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Affiliation(s)
- An-Yuan Guo
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN, USA
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Bloch B, Reshef A, Cohen T, Tafla A, Gathas S, Israel S, Gritsenko I, Kremer I, Ebstein RP. Preliminary effects of bupropion and the promoter region (HTTLPR) serotonin transporter (SLC6A4) polymorphism on smoking behavior in schizophrenia. Psychiatry Res 2010; 175:38-42. [PMID: 19995670 DOI: 10.1016/j.psychres.2008.12.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2007] [Revised: 12/14/2008] [Accepted: 12/30/2008] [Indexed: 11/25/2022]
Abstract
In the current study, we investigated how individual variants in the serotonin promoter gene, previously associated with smoking cessation and linked to anxiety-related personality traits, were associated with individual differences in responsiveness to bupropion and cognitive behavioral therapy (CBT) in a clinical population. We hypothesize that subjects with the long allele may be less responsive to treatment. Altogether 61 schizophrenic patients (46 M, 15 F) on stable neuroleptic medication were initially enrolled in a smoking reduction program (prospective, double-blind, placebo-controlled) including cognitive behavioral therapy plus placebo or CBT plus bupropion. Additionally, subjects were genotyped for a polymorphism in the serotonin transporter (SLC6A4). Thirty-two subjects (23 M, 9 F) completed a 14-week course of treatment. While both groups of subjects demonstrated significant reductions in smoking behavior due to CBT, subjects receiving bupropion did not show significant differences in smoking behavior when compared to placebo. In addition, analysis by SPSS repeated measures multivariate showed a significant sex by SLC6A4 genotype interaction on the number of cigarettes smoked. Only male subjects with at least one short promoter region allele (short/short and short/long combined) showed a reduction in cigarette consumption as a result of treatment. This study provides preliminary evidence of how polymorphisms in the serotonin transporter can be informative in predicting individual responses to smoking reduction therapy.
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Affiliation(s)
- Boaz Bloch
- Psychiatry Department, HaEmek Hospital, Afula, Israel
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Analysis of gene expression in two large schizophrenia cohorts identifies multiple changes associated with nerve terminal function. Mol Psychiatry 2009; 14:1083-94. [PMID: 19255580 DOI: 10.1038/mp.2009.18] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Schizophrenia is a severe psychiatric disorder with a world-wide prevalence of 1%. The pathophysiology of the illness is not understood, but is thought to have a strong genetic component with some environmental influences on aetiology. To gain further insight into disease mechanism, we used microarray technology to determine the expression of over 30 000 mRNA transcripts in post-mortem tissue from a brain region associated with the pathophysiology of the disease (Brodmann area 10: anterior prefrontal cortex) in 28 schizophrenic and 23 control patients. We then compared our study (Charing Cross Hospital prospective collection) with that of an independent prefrontal cortex dataset from the Harvard Brain Bank. We report the first direct comparison between two independent studies. A total of 51 gene expression changes have been identified that are common between the schizophrenia cohorts, and 49 show the same direction of disease-associated regulation. In particular, changes were observed in gene sets associated with synaptic vesicle recycling, transmitter release and cytoskeletal dynamics. This strongly suggests multiple, small but synergistic changes in gene expression that affect nerve terminal function.
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Mexal S, Berger R, Logel J, Ross RG, Freedman R, Leonard S. Differential regulation of alpha7 nicotinic receptor gene (CHRNA7) expression in schizophrenic smokers. J Mol Neurosci 2009; 40:185-95. [PMID: 19680823 DOI: 10.1007/s12031-009-9233-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 07/20/2009] [Indexed: 01/16/2023]
Abstract
The alpha7 neuronal nicotinic receptor gene (CHRNA7) has been implicated in the pathophysiology of schizophrenia by genetic and pharmacological studies. Expression of the alpha7* receptor, as measured by [(125)I]alpha-bungarotoxin autoradiography, is decreased in postmortem brain of schizophrenic subjects compared to non-mentally ill controls. Most schizophrenic patients are heavy smokers, with high levels of serum cotinine. Smoking changes the expression of multiple genes and differentially regulates gene expression in schizophrenic hippocampus. We examined the effects of smoking on CHRNA7 expression in the same tissue and find that smoking differentially regulates expression of both mRNA and protein for this gene. CHRNA7 mRNA and protein levels are significantly lower in schizophrenic nonsmokers compared to control nonsmokers and are brought to control levels in schizophrenic smokers. Sufficient protein but low surface expression of the alpha7* receptor, seen in the autoradiographic studies, suggests aberrant assembly or trafficking of the receptor.
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