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Lloyd D, Talmage D, Shannon Weickert C, Karl T. Reduced type III neuregulin 1 expression does not modulate the behavioural sensitivity of mice to acute Δ 9 -tetrahydrocannabinol (D 9 -THC). Pharmacol Biochem Behav 2018; 170:64-70. [DOI: 10.1016/j.pbb.2018.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/12/2018] [Accepted: 05/07/2018] [Indexed: 12/15/2022]
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Olaya JC, Heusner CL, Matsumoto M, Sinclair D, Kondo MA, Karl T, Shannon Weickert C. Overexpression of Neuregulin 1 Type III Confers Hippocampal mRNA Alterations and Schizophrenia-Like Behaviors in Mice. Schizophr Bull 2018; 44:865-875. [PMID: 28981869 PMCID: PMC6007747 DOI: 10.1093/schbul/sbx122] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Neuregulin 1 (NRG1) is a schizophrenia candidate gene whose protein product is involved in neuronal migration, survival, and synaptic plasticity via production of specific isoforms. Importantly, NRG1 type III (NRG1 III) mRNA is increased in humans inheriting a schizophrenia risk haplotype for the NRG1 gene (HapICE), and NRG1 protein levels can be elevated in schizophrenia. The nature by which NRG1 type III overexpression results in schizophrenia-like behavior and brain pathology remains unclear, therefore we constructed a transgenic mouse with Nrg1 III overexpression in forebrain neurons (CamKII kinase+). Here, we demonstrate construct validity for this mouse model, as juvenile and adult Nrg1 III transgenic mice exhibit an overexpression of Nrg1 III mRNA and Nrg1 protein in multiple brain regions. Furthermore, Nrg1 III transgenic mice have face validity as they exhibit schizophrenia-relevant behavioral phenotypes including deficits in social preference, impaired fear-associated memory, and reduced prepulse inhibition. Additionally, microarray assay of hippocampal mRNA uncovered transcriptional alterations downstream of Nrg1 III overexpression, including changes in serotonin receptor 2C and angiotensin-converting enzyme. Transgenic mice did not exhibit other schizophrenia-relevant behaviors including hyperactivity, social withdrawal, or an increased vulnerability to the effects of MK-801 malate. Our results indicate that this novel Nrg1 III mouse is valid for modeling potential pathological mechanisms of some schizophrenia-like behaviors, for determining what other neurobiological changes may be downstream of elevated NRG1 III levels and for preclinically testing therapeutic strategies that may be specifically efficacious in patients with the NRG1 (HapICE) risk genotype.
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Affiliation(s)
- Juan C Olaya
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, NSW, Australia,School of Psychiatry, University of New South Wales, Sydney, Australia
| | | | | | - Duncan Sinclair
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, NSW, Australia,School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Mari A Kondo
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, NSW, Australia,School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Tim Karl
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, NSW, Australia,School of Medicine, Western Sydney University, Campbelltown, Australia
| | - Cynthia Shannon Weickert
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, NSW, Australia,School of Psychiatry, University of New South Wales, Sydney, Australia,To whom correspondence should be addressed; Neuroscience Research Australia, Barker Street, Randwick, NSW 2031, Australia; tel: +61-2-9399-1117, fax: +61-2-9399-1005, e-mail:
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Chesworth R, Long LE, Weickert CS, Karl T. The Endocannabinoid System across Postnatal Development in Transmembrane Domain Neuregulin 1 Mutant Mice. Front Psychiatry 2018; 9:11. [PMID: 29467679 PMCID: PMC5808294 DOI: 10.3389/fpsyt.2018.00011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 01/15/2018] [Indexed: 12/18/2022] Open
Abstract
The use of cannabis is a well-established component risk factor for schizophrenia, particularly in adolescent individuals with genetic predisposition for the disorder. Alterations to the endocannabinoid system have been found in the prefrontal cortex of patients with schizophrenia. Thus, we assessed whether molecular alterations exist in the endocannabinoid signalling pathway during brain development in a mouse model for the schizophrenia risk gene neuregulin 1 (Nrg1). We analysed transcripts encoding key molecules of the endocannabinoid system in heterozygous transmembrane domain Nrg1 mutant mice (Nrg1 TM HET), which is known to have increased sensitivity to cannabis exposure. Tissue from the prelimbic cortex and hippocampus of male and female Nrg1 TM HET mice and wild type-like littermates was collected at postnatal days (PNDs) 7, 10, 14, 21, 28, 35, 49, and 161. Quantitative polymerase chain reaction was conducted to assess mRNA levels of cannabinoid receptor 1 (CB1R) and enzymes for the synthesis and breakdown of the endocannabinoid 2-arachidonoylglycerol [i.e., diacylglycerol lipase alpha (DAGLα), monoglyceride lipase (MGLL), and α/β-hydrolase domain-containing 6 (ABHD6)]. No sex differences were found for any transcripts in either brain region; thus, male and female data were pooled. Hippocampal and cortical mRNA expression of DAGLα, MGLL, and ABHD6 increased until PND 21-35 and then decreased and stabilised for the rest of postnatal development. Hippocampal CB1R mRNA expression increased until PND 21 and decreased after this age. Expression levels of these endocannabinoid markers did not differ in Nrg1 TM HET compared to control mice at any time point. Here, we demonstrate dynamic changes in the developmental trajectory of several key endocannabinoid system transcripts in the mouse brain, which may correspond with periods of endocannabinoid system maturation. Nrg1 TM HET mutation did not alter the developmental trajectory of the endocannabinoid markers assessed, suggesting that other mechanisms may be responsible for the exaggerated cannabinoid susceptibility in these mice.
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Affiliation(s)
- Rose Chesworth
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Leonora E Long
- Schizophrenia Research Institute, Sydney, NSW, Australia.,Neuroscience Research Australia, Randwick, NSW, Australia
| | - Cynthia Shannon Weickert
- Schizophrenia Research Institute, Sydney, NSW, Australia.,Neuroscience Research Australia, Randwick, NSW, Australia.,School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - Tim Karl
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia.,Schizophrenia Research Institute, Sydney, NSW, Australia.,Neuroscience Research Australia, Randwick, NSW, Australia
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Clarke DJ, Stuart J, McGregor IS, Arnold JC. Endocannabinoid dysregulation in cognitive and stress-related brain regions in the Nrg1 mouse model of schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2017; 72:9-15. [PMID: 27521758 DOI: 10.1016/j.pnpbp.2016.08.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/09/2016] [Accepted: 08/09/2016] [Indexed: 02/06/2023]
Abstract
The endocannabinoid system is dysregulated in schizophrenia. Mice with heterozygous deletion of neuregulin 1 (Nrg1 HET mice) provide a well-characterised animal model of schizophrenia, and display enhanced sensitivity to stress and cannabinoids during adolescence. However, no study has yet determined whether these mice have altered brain endocannabinoid concentrations. Nrg1 application to hippocampal slices decreased 2-arachidonoylglycerol (2-AG) signalling and disrupted long-term depression, a form of synaptic plasticity critical to spatial learning. Therefore we specifically aimed to examine whether Nrg1 HET mice exhibit increased 2-AG concentrations and disruption of spatial learning. As chronic stress influences brain endocannabinoids, we also sought to examine whether Nrg1 deficiency moderates adolescent stress-induced alterations in brain endocannabinoids. Adolescent Nrg1 HET and wild-type (WT) mice were submitted to chronic restraint stress and brain endocannabinoid concentrations were analysed. A separate cohort of WT and Nrg1 HET mice was also assessed for spatial learning performance in the Morris Water Maze. Partial genetic deletion of Nrg1 increased anandamide concentrations in the amygdala and decreased 2-AG concentrations in the hypothalamus. Further, Nrg1 HET mice exhibited increased 2-AG concentrations in the hippocampus and impaired spatial learning performance. Chronic adolescent stress increased anandamide concentrations in the amygdala, however, Nrg1 disruption did not influence this stress-induced change. These results demonstrate for the first time in vivo interplay between Nrg1 and endocannabinoids in the brain. Our results demonstrate that aberrant Nrg1 and endocannabinoid signalling may cooperate in the hippocampus to impair cognition, and that Nrg1 deficiency alters endocannabinoid signalling in brain stress circuitry.
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Affiliation(s)
- David J Clarke
- Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, Australia; Brain and Mind Centre, University of Sydney, Sydney, Australia
| | - Jordyn Stuart
- Lambert Initiative of Cannabinoid Therapeutics, University of Sydney, Sydney, Australia
| | - Iain S McGregor
- Lambert Initiative of Cannabinoid Therapeutics, University of Sydney, Sydney, Australia
| | - Jonathon C Arnold
- Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, Australia; Brain and Mind Centre, University of Sydney, Sydney, Australia; Lambert Initiative of Cannabinoid Therapeutics, University of Sydney, Sydney, Australia.
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Sex differences in animal models of schizophrenia shed light on the underlying pathophysiology. Neurosci Biobehav Rev 2016; 67:41-56. [DOI: 10.1016/j.neubiorev.2015.10.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/28/2015] [Accepted: 10/26/2015] [Indexed: 12/20/2022]
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Long LE, Anderson P, Frank E, Shaw A, Liu S, Huang XF, Pinault D, Karl T, O’Brien TJ, Shannon Weickert C, Jones NC. Neuregulin 1 expression and electrophysiological abnormalities in the Neuregulin 1 transmembrane domain heterozygous mutant mouse. PLoS One 2015; 10:e0124114. [PMID: 25992564 PMCID: PMC4437646 DOI: 10.1371/journal.pone.0124114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 03/10/2015] [Indexed: 01/29/2023] Open
Abstract
Background The Neuregulin 1 transmembrane domain heterozygous mutant (Nrg1 TM HET) mouse is used to investigate the role of Nrg1 in brain function and schizophrenia-like behavioural phenotypes. However, the molecular alterations in brain Nrg1 expression that underpin the behavioural observations have been assumed, but not directly determined. Here we comprehensively characterise mRNA Nrg1 transcripts throughout development of the Nrg1 TM HET mouse. In addition, we investigate the regulation of high-frequency (gamma) electrophysiological oscillations in this mutant mouse to associate molecular changes in Nrg1 with a schizophrenia-relevant neurophysiological profile. Methods Using exonic probes spanning the cysteine-rich, epidermal growth factor (EGF)-like, transmembrane and intracellular domain encoding regions of Nrg1, mRNA levels were measured using qPCR in hippocampus and frontal cortex from male and female Nrg1 TM HET and wild type-like (WT) mice throughout development. We also performed electrophysiological recordings in adult mice and analysed gamma oscillatory at baseline, in responses to auditory stimuli and to ketamine. Results In both hippocampus and cortex, Nrg1 TM HET mice show significantly reduced expression of the exon encoding the transmembrane domain of Nrg1 compared with WT, but unaltered mRNA expression encoding the extracellular bioactive EGF-like and the cysteine-rich (type III) domains, and development-specific and region-specific reductions in the mRNA encoding the intracellular domain. Hippocampal Nrg1 protein expression was not altered, but NMDA receptor NR2B subunit phosphorylation was lower in Nrg1 TM HET mice. We identified elevated ongoing and reduced sensory-evoked gamma power in Nrg1 TM HET mice. Interpretation We found no evidence to support the claim that the Nrg1 TM HET mouse represents a simple haploinsufficient model. Further research is required to explore the possibility that mutation results in a gain of Nrg1 function.
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Affiliation(s)
- Leonora E. Long
- Schizophrenia Research Institute, Sydney, New South Wales, Australia
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Paul Anderson
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Elisabeth Frank
- Schizophrenia Research Institute, Sydney, New South Wales, Australia
- University of Wollongong, Wollongong, New South Wales, Australia
| | - Alex Shaw
- Schizophrenia Research Institute, Sydney, New South Wales, Australia
- Neuroscience Research Australia, Randwick, New South Wales, Australia
| | - Shijie Liu
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Xu-Feng Huang
- Schizophrenia Research Institute, Sydney, New South Wales, Australia
- University of Wollongong, Wollongong, New South Wales, Australia
| | - Didier Pinault
- INSERM U1114, psychopathologie cognitive et physiopathologie de la schizophrénie, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
| | - Tim Karl
- Schizophrenia Research Institute, Sydney, New South Wales, Australia
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Terence J. O’Brien
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Cynthia Shannon Weickert
- Schizophrenia Research Institute, Sydney, New South Wales, Australia
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail: (CSW); (NCJ)
| | - Nigel C. Jones
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
- * E-mail: (CSW); (NCJ)
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Suárez-Pinilla P, Roíz-Santiañez R, Mata I, Ortiz-García de la Foz V, Brambilla P, Fañanas L, Valle-San Román N, Crespo-Facorro B. Progressive Structural Brain Changes and NRG1 Gene Variants in First-Episode Nonaffective Psychosis. Neuropsychobiology 2015; 71:103-111. [PMID: 25871612 DOI: 10.1159/000370075] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 11/11/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND Structural brain abnormalities are already present during the early phases of psychosis, but factors underlying brain volume changes are still not well understood. The neuregulin 1 gene (NRG1), influencing neurodevelopment and neuroplasticity, has been associated with schizophrenia. Our aim was to examine whether variations in the NRG1 gene (SNP8NRG221132, SNP8NRG6221533 and SNP8NRG243177 polymorphisms) influence longitudinal changes in the brain during a first episode of psychosis (FEP). METHODS A 3-year follow-up magnetic resonance imaging (MRI) study was performed. Fifty-nine minimally medicated patients who were experiencing FEP and 14 healthy control individuals underwent genotyping and structural brain MRI at baseline and at 1- and 3-year follow-up. A comparison of brain volumes, gray matter, white matter (WM), lateral ventricles (LV), cortical cerebrospinal fluid, and thalamus and caudate was made between the groups according to their genotype. RESULTS In patients, the SNP8NRG6221533 risk C allele was significantly associated with increased LV volume across time. C allele carriers had significantly less WM compared with subjects homozygous for the T allele after the follow-up. No other significant differences were observed among subgroups. No significant changes according to the genotypes were found in healthy individuals. CONCLUSION Our findings suggest that variations of neurodevelopment-related genes, such as the NRG1 gene, can contribute to brain abnormalities described in early phases of schizophrenia and progressive changes during the initial years of the illness. To our knowledge, it is the first time that a relation between NRG1 polymorphisms and longitudinal brain changes is reported. © 2015 S. Karger AG, Basel.
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Affiliation(s)
- Paula Suárez-Pinilla
- Department of Psychiatry, University Hospital Marqués de Valdecilla, School of Medicine, University of Cantabria, Santander, Spain
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Chohan TW, Boucher AA, Spencer JR, Kassem MS, Hamdi AA, Karl T, Fok SY, Bennett MR, Arnold JC. Partial genetic deletion of neuregulin 1 modulates the effects of stress on sensorimotor gating, dendritic morphology, and HPA axis activity in adolescent mice. Schizophr Bull 2014; 40:1272-84. [PMID: 24442851 PMCID: PMC4193694 DOI: 10.1093/schbul/sbt193] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Stress has been linked to the pathogenesis of schizophrenia. Genetic variation in neuregulin 1 (NRG1) increases the risk of developing schizophrenia and may help predict which high-risk individuals will transition to psychosis. NRG1 also modulates sensorimotor gating, a schizophrenia endophenotype. We used an animal model to demonstrate that partial genetic deletion of Nrg1 interacts with stress to promote neurobehavioral deficits of relevance to schizophrenia. Nrg1 heterozygous (HET) mice displayed greater acute stress-induced anxiety-related behavior than wild-type (WT) mice. Repeated stress in adolescence disrupted the normal development of higher prepulse inhibition of startle selectively in Nrg1 HET mice but not in WT mice. Further, repeated stress increased dendritic spine density in pyramidal neurons of the medial prefrontal cortex (mPFC) selectively in Nrg1 HET mice. Partial genetic deletion of Nrg1 also modulated the adaptive response of the hypothalamic-pituitary-adrenal axis to repeated stress, with Nrg1 HET displaying a reduced repeated stress-induced level of plasma corticosterone than WT mice. Our results demonstrate that Nrg1 confers vulnerability to repeated stress-induced sensorimotor gating deficits, dendritic spine growth in the mPFC, and an abberant endocrine response in adolescence.
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Affiliation(s)
- Tariq W. Chohan
- The Brain and Mind Research Institute, University of Sydney, Sydney, NSW 2006, Australia;,Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, NSW 2006, Australia
| | - Aurelie A. Boucher
- The Brain and Mind Research Institute, University of Sydney, Sydney, NSW 2006, Australia
| | - Jarrah R. Spencer
- The Brain and Mind Research Institute, University of Sydney, Sydney, NSW 2006, Australia;,Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, NSW 2006, Australia
| | - Mustafa S. Kassem
- The Brain and Mind Research Institute, University of Sydney, Sydney, NSW 2006, Australia
| | - Areeg A. Hamdi
- Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, NSW 2006, Australia
| | - Tim Karl
- Neuroscience Research Australia, Randwick, NSW 2031, Australia
| | - Sandra Y. Fok
- The Brain and Mind Research Institute, University of Sydney, Sydney, NSW 2006, Australia
| | - Maxwell R. Bennett
- The Brain and Mind Research Institute, University of Sydney, Sydney, NSW 2006, Australia
| | - Jonathon C. Arnold
- The Brain and Mind Research Institute, University of Sydney, Sydney, NSW 2006, Australia;,Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, NSW 2006, Australia;,*To whom correspondence should be addressed; The Brain and Mind Research Institute, University of Sydney, 94-100 Mallett Street, Sydney, Australia; tel: +61-2-9351-0812, e-mail:
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Deng C, Dean B. Mapping the pathophysiology of schizophrenia: interactions between multiple cellular pathways. Front Cell Neurosci 2013; 7:238. [PMID: 24348332 PMCID: PMC3842583 DOI: 10.3389/fncel.2013.00238] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 11/13/2013] [Indexed: 11/16/2022] Open
Affiliation(s)
- Chao Deng
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute Wollongong, NSW, Australia ; Centre for Translational Neuroscience, School of Medicine, University of Wollongong Wollongong, NSW, Australia ; Schizophrenia Research Institute Sydney, NSW, Australia
| | - Brian Dean
- Molecular Psychiatry Laboratory, Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia ; Department of Psychiatry, The University of Melbourne Parkville, VIC, Australia
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Burrows EL, Hannan AJ. Decanalization mediating gene-environment interactions in schizophrenia and other psychiatric disorders with neurodevelopmental etiology. Front Behav Neurosci 2013; 7:157. [PMID: 24312026 PMCID: PMC3826253 DOI: 10.3389/fnbeh.2013.00157] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 10/21/2013] [Indexed: 11/13/2022] Open
Affiliation(s)
- Emma L. Burrows
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
| | - Anthony J. Hannan
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, ParkvilleVIC, Australia
- Department of Anatomy and Neuroscience, The University of Melbourne, ParkvilleVIC, Australia
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Karl T. Neuregulin 1: a prime candidate for research into gene-environment interactions in schizophrenia? Insights from genetic rodent models. Front Behav Neurosci 2013; 7:106. [PMID: 23966917 PMCID: PMC3744031 DOI: 10.3389/fnbeh.2013.00106] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/29/2013] [Indexed: 11/13/2022] Open
Abstract
Schizophrenia is a multi-factorial disease characterized by a high heritability and environmental risk factors. In recent years, an increasing number of researchers worldwide have started investigating the “two-hit hypothesis” of schizophrenia predicting that genetic and environmental risk factors (GxE) interactively cause the development of the disorder. This work is starting to produce valuable new animal models and reveal novel insights into the pathophysiology of schizophrenia. This mini review will focus on recent advancements in the field made by challenging mutant and transgenic rodent models for the schizophrenia candidate gene neuregulin 1 (NRG1) with particular environmental factors. It will outline results obtained from mouse and rat models for various Nrg1 isoforms/isoform types (e.g., transmembrane domain Nrg1, Type II Nrg1), which have been exposed to different forms of stress (acute versus chronic, restraint versus social) and housing conditions (standard laboratory versus minimally enriched housing). These studies suggest Nrg1 as a prime candidate for GxE interactions in schizophrenia rodent models and that the use of rodent models will enable a better understanding of GxE interactions and the underlying mechanisms.
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Affiliation(s)
- Tim Karl
- Neuroscience Research Australia Randwick, NSW, Australia ; Schizophrenia Research Institute Darlinghurst, NSW, Australia ; School of Medical Sciences, University of New South Wales NSW, Australia
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Kannan G, Sawa A, Pletnikov MV. Mouse models of gene-environment interactions in schizophrenia. Neurobiol Dis 2013; 57:5-11. [PMID: 23748077 DOI: 10.1016/j.nbd.2013.05.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/10/2013] [Accepted: 05/20/2013] [Indexed: 01/20/2023] Open
Abstract
Gene-environment interactions (GEIs) likely play significant roles in the pathogenesis of schizophrenia and underlie differences in pathological, behavioral, and clinical presentations of the disease. Findings from epidemiology and psychiatric genetics have assisted in the generation of animal models of GEI relevant to schizophrenia. These models may provide a foundation for elucidating the molecular, cellular, and circuitry mechanisms that mediate GEI in schizophrenia. Here we critically review current mouse models of GEI related to schizophrenia, describe directions for their improvement, and propose endophenotypes to provide a more tangible basis for molecular studies of pathways of GEI and facilitate the identification of novel therapeutic targets.
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Affiliation(s)
- Geetha Kannan
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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