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Arraes GC, Barreto FS, Vasconcelos GS, Lima CNDC, da Silva FER, Ribeiro WLC, de Sousa FCF, Furtado CLM, Macêdo DS. Long-term Environmental Enrichment Normalizes Schizophrenia-like Abnormalities and Promotes Hippocampal Slc6a4 Promoter Demethylation in Mice Submitted to a Two-hit Model. Neuroscience 2024; 551:205-216. [PMID: 38843988 DOI: 10.1016/j.neuroscience.2024.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/15/2024] [Accepted: 05/20/2024] [Indexed: 06/15/2024]
Abstract
Here, we explored the impact of prolonged environmental enrichment (EE) on behavioral, neurochemical, and epigenetic changes in the serotonin transporter gene in mice subjected to a two-hit schizophrenia model. The methodology involved administering the viral mimetic PolyI:C to neonatal Swiss mice as a first hit during postnatal days (PND) 5-7, or a sterile saline solution as a control. At PND21, mice were randomly assigned either to standard environment (SE) or EE housing conditions. Between PND35-44, the PolyI:C-treated group was submitted to various unpredictable stressors, constituting the second hit. Behavioral assessments were conducted on PND70, immediately after the final EE exposure. Following the completion of behavioral assessments, we evaluated the expression of proteins in the hippocampus that are indicative of microglial activation, such as Iba-1, as well as related to neurogenesis, including doublecortin (Dcx). We also performed methylation analysis on the serotonin transporter gene (Slc6a4) to investigate alterations in serotonin signaling. The findings revealed that EE for 50 days mitigated sensorimotor gating deficits and working memory impairments in two-hit mice and enhanced their locomotor and exploratory behaviors. EE also normalized the overexpression of hippocampal Iba-1 and increased the expression of hippocampal Dcx. Additionally, we observed hippocampal demethylation of the Slc6a4 gene in the EE-exposed two-hit group, indicating epigenetic reprogramming. These results contribute to the growing body of evidence supporting the protective effects of long-term EE in counteracting behavioral disruptions caused by the two-hit schizophrenia model, pointing to enhanced neurogenesis, diminished microglial activation, and epigenetic modifications of serotonergic pathways as underlying mechanisms.
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Affiliation(s)
- Greicy Coelho Arraes
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; Christus University Center (Unichristus-CE), Fortaleza, CE, Brazil
| | - Francisco Stefânio Barreto
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; Laboratory of Experimental Oncology, Postgraduate Program in Translational Medicine, Drug Research and Development Center, Federal University of Ceara, Fortaleza, Ceará, Brazil
| | - Germana Silva Vasconcelos
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Camila Nayane de Carvalho Lima
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; Translational Psychiatry Program, Louis A. Faillace, MD, Department of Psychiatry and Behavioral Sciences at McGovern Medical School, The University of Texas Health Science Center at Houston (UT Health), Houston, TX, USA.
| | - Francisco Eliclécio Rodrigues da Silva
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | | | - Francisca Cléa Florenço de Sousa
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil.
| | - Cristiana Libardi Miranda Furtado
- Laboratory of Experimental Oncology, Postgraduate Program in Translational Medicine, Drug Research and Development Center, Federal University of Ceara, Fortaleza, Ceará, Brazil; Graduate Program in Medical Sciences, Experimental Biology Center - NUBEX, University of Fortaleza, UNIFOR, Fortaleza, Ceará, Brazil
| | - Danielle S Macêdo
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; National Institute for Translational Medicine (INCT-TM. CNPq), Brazil.
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Li Y, Lu J, Zhang J, Gui W, Xie W. Molecular insights into enriched environments and behavioral improvements in autism: a systematic review and meta-analysis. Front Psychiatry 2024; 15:1328240. [PMID: 38362032 PMCID: PMC10867156 DOI: 10.3389/fpsyt.2024.1328240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 01/09/2024] [Indexed: 02/17/2024] Open
Abstract
Aims Autism is a multifaceted developmental disorder of the nervous system, that necessitates novel therapeutic approaches beyond traditional medications and psychosomatic therapy, such as appropriate sensory integration training. This systematic mapping review aims to synthesize existing knowledge on enriching environmental interventions as an alternative avenue for improving autism, guiding future research and practice. Method A comprehensive search using the terms ASD and Enriched Environment was conducted across PubMed, EMBASE, ISI, Cochrane, and OVID databases. Most of the literature included in this review was derived from animal model experiments, with a particular focus on assessing the effect of EE on autism-like behavior, along with related pathways and molecular mechanisms. Following extensive group discussion and screening, a total of 19 studies were included for analysis. Results Enriched environmental interventions exhibited the potential to induce both behavioral and biochemical changes, ameliorating autism-like behaviors in animal models. These improvements were attributed to the targeting of BDNF-related pathways, enhanced neurogenesis, and the regulation of glial inflammation. Conclusion This paper underscores the positive impact of enriched environmental interventions on autism through a review of existing literature. The findings contribute to a deeper understanding of the underlying brain mechanisms associated with this intervention.
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Affiliation(s)
- Yutong Li
- School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Jing Lu
- School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Jing Zhang
- Department of Sports Medicine, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Wenxin Gui
- School of Mental Health, Wenzhou Medical University, Wenzhou, China
| | - Weijie Xie
- School of Mental Health, Wenzhou Medical University, Wenzhou, China
- Clinical Research Center for Mental Disorders, Shanghai Pudong New Area Mental Health Center, Tongji University School of Medicine, Shanghai, China
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Nachtigall EG, de Freitas JDR, Marcondes LA, Furini CRG. Memory persistence induced by environmental enrichment is dependent on different brain structures. Physiol Behav 2023; 272:114375. [PMID: 37806510 DOI: 10.1016/j.physbeh.2023.114375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 09/24/2023] [Accepted: 10/05/2023] [Indexed: 10/10/2023]
Abstract
Environmental enrichment (EE) has been demonstrated to have a beneficial effect on different functions of the central nervous system in several mammal species, being used to improve behavior and cell damage in various neurological and psychiatric diseases. However, little has been investigated on the effect of EE in healthy animals, particularly regarding its impact on memory persistence and the brain structures involved. Therefore, here we verified in male Wistar rats that contextual fear conditioning (CFC) memory persistence, tested 28 days after the CFC training session, was facilitated by 5 weeks of exposure to EE, with no effect in groups tested 7 or 14 days after CFC training. However, a two-week exposure to EE did not affect memory persistence. Moreover, we investigated the role of specific brain regions in mediating the effect of EE on memory persistence. We conducted inactivation experiments using the GABAergic agonist Muscimol to target the basolateral amygdala (BLA), medial prefrontal cortex (mPFC), and CA1 region of the hippocampus (CA1). Inactivation of the BLA immediately and 12 h after CFC training impaired the effect of EE on memory persistence. Similarly, inactivation of the CA1 region and mPFC 12 h after training, but not immediately, also impaired the effect of EE on memory persistence. These results have important scientific implications as they shed new light on the effect of an enriched environment on memory persistence and the brain structures involved, thereby helping elucidate how an environment rich in experiences can modify the persistence of learned information.
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Affiliation(s)
- Eduarda G Nachtigall
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3rd floor, 90610-000, Porto Alegre, RS, Brazil
| | - Júlia D R de Freitas
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3rd floor, 90610-000, Porto Alegre, RS, Brazil
| | - Lucas Aschidamini Marcondes
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3rd floor, 90610-000, Porto Alegre, RS, Brazil
| | - Cristiane R G Furini
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3rd floor, 90610-000, Porto Alegre, RS, Brazil.
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Gattuso JJ, Wilson C, Hannan AJ, Renoir T. Acute administration of the NMDA receptor antagonists ketamine and MK-801 reveals dysregulation of glutamatergic signalling and sensorimotor gating in the Sapap3 knockout mouse model of compulsive-like behaviour. Neuropharmacology 2023; 239:109689. [PMID: 37597609 DOI: 10.1016/j.neuropharm.2023.109689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/30/2023] [Accepted: 08/15/2023] [Indexed: 08/21/2023]
Abstract
Obsessive-compulsive disorder (OCD) is characterised by excessive intrusive thoughts that may cause an individual to engage in compulsive behaviours. Frontline pharmacological treatments (i.e., selective serotonin reuptake inhibitors (SSRIs)) leave approximately 40% of patients refractory to treatment. To investigate the possibility of novel pharmacological therapies for OCD, as well as the potential mechanisms underlying its pathology, we used the Sapap3 knockout (KO) mouse model of OCD, which exhibits increased anxiety and compulsive grooming behaviours. Firstly, we investigated whether administration of the NMDA receptor (NMDAR) antagonist ketamine (30 mg/kg), would reduce anxiety and grooming behaviour in Sapap3 KO mice. Anxiety-like behaviour was measured via time spent in the light component of the light-dark box test. Grooming behaviour was recorded and scored in freely moving mice. In line with previous works conducted in older animals (i.e. typically between 6 and 9 months of age), we confirmed here that Sapap3 KO mice exhibit an anxious, compulsive grooming, hypolocomotive and reduced body weight phenotype even at a younger age (i.e., 2-3 months of age). However, we found that acute administration of ketamine did not cause a reduction in anxiety or grooming behaviour. We then investigated in vivo glutamatergic function via the administration of a different NMDAR antagonist, MK-801 (0.25 mg/kg), prior to locomotion and prepulse inhibition assays. We found evidence of altered functional NMDAR activity, as well as sexually dimorphic prepulse inhibition, a measure of sensorimotor gating, in Sapap3 KO mice. These results are suggestive of in vivo glutamatergic dysfunction and their functional consequences, enabling future research to further investigate novel treatments for OCD.
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Affiliation(s)
- James J Gattuso
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia
| | - Carey Wilson
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia.
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Alarcón TA, Presti-Silva SM, Simões APT, Ribeiro FM, Pires RGW. Molecular mechanisms underlying the neuroprotection of environmental enrichment in Parkinson's disease. Neural Regen Res 2023; 18:1450-1456. [PMID: 36571341 PMCID: PMC10075132 DOI: 10.4103/1673-5374.360264] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Parkinson's disease is the most common movement disorder, affecting about 1% of the population over the age of 60 years. Parkinson's disease is characterized clinically by resting tremor, bradykinesia, rigidity and postural instability, as a result of the progressive loss of nigrostriatal dopaminergic neurons. In addition to this neuronal cell loss, Parkinson's disease is characterized by the accumulation of intracellular protein aggregates, Lewy bodies and Lewy neurites, composed primarily of the protein α-synuclein. Although it was first described almost 200 years ago, there are no disease-modifying drugs to treat patients with Parkinson's disease. In addition to conventional therapies, non-pharmacological treatment strategies are under investigation in patients and animal models of neurodegenerative disorders. Among such strategies, environmental enrichment, comprising physical exercise, cognitive stimulus, and social interactions, has been assessed in preclinical models of Parkinson's disease. Environmental enrichment can cause structural and functional changes in the brain and promote neurogenesis and dendritic growth by modifying gene expression, enhancing the expression of neurotrophic factors and modulating neurotransmission. In this review article, we focus on the current knowledge about the molecular mechanisms underlying environmental enrichment neuroprotection in Parkinson's disease, highlighting its influence on the dopaminergic, cholinergic, glutamatergic and GABAergic systems, as well as the involvement of neurotrophic factors. We describe experimental pre-clinical data showing how environmental enrichment can act as a modulator in a neurochemical and behavioral context in different animal models of Parkinson's disease, highlighting the potential of environmental enrichment as an additional strategy in the management and prevention of this complex disease.
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Affiliation(s)
- Tamara Andrea Alarcón
- Department of Physiological Sciences; Laboratory of Molecular and Behavioral Neurobiology, Health Science Center, Universidade Federal do Espirito Santo, Vitoria, Brazil
| | - Sarah Martins Presti-Silva
- Laboratory of Molecular and Behavioral Neurobiology, Health Science Center, Universidade Federal do Espirito Santo, Vitoria; Department of Biochemistry and Immunology, Institute o Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, Belo Horizonte, Brazil
| | - Ana Paula Toniato Simões
- Department of Physiological Sciences; Laboratory of Molecular and Behavioral Neurobiology, Health Science Center, Universidade Federal do Espirito Santo, Vitoria, Brazil
| | - Fabiola Mara Ribeiro
- Department of Biochemistry and Immunology, Institute o Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, Belo Horizonte, Brazil
| | - Rita Gomes Wanderley Pires
- Department of Physiological Sciences; Laboratory of Molecular and Behavioral Neurobiology, Health Science Center, Universidade Federal do Espirito Santo, Vitoria, Brazil
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Durairaja A, Pandey S, Kahl E, Fendt M. Nasal administration of orexin A partially rescues dizocilpine-induced cognitive impairments in female C57BL/6J mice. Behav Brain Res 2023; 450:114491. [PMID: 37172740 DOI: 10.1016/j.bbr.2023.114491] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/15/2023]
Abstract
Sex difference has been reported in several behavioural endophenotypes of neuropsychiatric disorder in both rodents and humans. However, sex difference in cognitive symptoms associated with neuropsychiatric disorders has not been studied in detail. In this study, we induced cognitive impairment using the NMDA receptor antagonist, dizocilpine (MK-801), in male and female C57BL/6J mice and performed a visual discrimination task in an automated touchscreen system. We found that discrimination performance decreased with increased doses of MK-801 in both sexes. However, female mice showed stronger deficit in discrimination performance than the male mice especially after administration of low (0.01mg/kg) and high (0.15mg/kg) doses of MK-801. Furthermore, we tested if administration of orexin A, orexin-1 receptor antagonist SB-334867 or orexin-2 receptor antagonist EMPA rescued MK-801 (0.15mg/kg) induced cognitive impairment in visual discrimination. We found that nasal administration of orexin A partially rescued the cognitive impairment induced by MK-801 in females but not in males. Taken together, our data show that female C57BL/6J mice are more sensitive compared to males to some doses of MK-801 in discrimination learning task and that orexin A partially rescues this cognitive impairment in females.
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Affiliation(s)
- Archana Durairaja
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany.
| | - Samiksha Pandey
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany; Integrative Neuroscience Programme, Otto-von-Guericke University, Magdeburg, Germany
| | - Evelyn Kahl
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany; Center of Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany
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Malone SG, Shaykin JD, Stairs DJ, Bardo MT. Neurobehavioral effects of environmental enrichment and drug abuse vulnerability: An updated review. Pharmacol Biochem Behav 2022; 221:173471. [PMID: 36228739 DOI: 10.1016/j.pbb.2022.173471] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/16/2022] [Accepted: 10/05/2022] [Indexed: 12/14/2022]
Abstract
Environmental enrichment consisting of social peers and novel objects is known to alter neurobiological functioning and have an influence on the behavioral effects of drugs of abuse in preclinical rodent models. An earlier review from our laboratory (Stairs and Bardo, 2009) provided an overview of enrichment-specific changes in addiction-like behaviors and neurobiology. The current review updates the literature in this extensive field. Key findings from this updated review indicate that enrichment produces positive outcomes in drug abuse vulnerability beyond just psychostimulants. Additionally, recent studies indicate that enrichment activates key genes involved in cell proliferation and protein synthesis in nucleus accumbens and enhances growth factors in hippocampus and neurotransmitter signaling pathways in prefrontal cortex, amygdala, and hypothalamus. Remaining gaps in the literature and future directions for environmental enrichment and drug abuse research are identified.
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Affiliation(s)
- Samantha G Malone
- Department of Psychology, University of Kentucky, BBSRB, 741 S. Limestone, Lexington, KY, USA
| | - Jakob D Shaykin
- Department of Psychology, University of Kentucky, BBSRB, 741 S. Limestone, Lexington, KY, USA
| | - Dustin J Stairs
- Department of Psychological Science, Creighton University, Hixson-Lied Science Building, 2500 California Plaza, Omaha, NE, USA
| | - Michael T Bardo
- Department of Psychology, University of Kentucky, BBSRB, 741 S. Limestone, Lexington, KY, USA.
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Xu J, Li Y, Tian B, Liu H, Wu S, Wang W. The effects and mechanism of environmental enrichment on MK-801 induced cognitive impairment in rodents with schizophrenia. Front Cell Neurosci 2022; 16:1024649. [PMID: 36246525 PMCID: PMC9556631 DOI: 10.3389/fncel.2022.1024649] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 09/13/2022] [Indexed: 12/02/2022] Open
Abstract
Schizophrenia is a severe mental disorder characterized by positive, negative, and cognitive symptoms. Cognitive symptoms are a kind of symptoms with high incidence and great impact on patients. There is no effective treatment in clinical practice. N-methyl-d-aspartic acid (NMDA) receptor hypofunction may be an important cause of cognitive symptoms. MK-801 (also named Dizocilpine), a noncompetitive antagonist of NMDA receptor, is often used to construct a model of NMDA receptor dysfunction. In terms of treatment, environmental enrichment (EE) as an environmental intervention can effectively improve the symptoms of cognitive impairment in rodents. In this paper, we first briefly introduce the background of cognitive symptoms and EE in schizophrenia, and then investigate the manifestations of MK-801 induced cognitive impairment, the improvement of EE on these cognitive impairments based on the MK-801 induced schizophrenia rodent models, and the possible mechanism of EE in improving cognitive symptoms. This article reviews the literature in recent years, which provides an important reference for MK-801 to construct a cognitive symptom model of schizophrenia and the mechanism of EE in improving cognitive symptoms of schizophrenia.
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Dogra S, Conn PJ. Metabotropic glutamate receptors as emerging targets for the treatment of schizophrenia. Mol Pharmacol 2022; 101:275-285. [PMID: 35246479 PMCID: PMC9092465 DOI: 10.1124/molpharm.121.000460] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/22/2022] [Indexed: 11/22/2022] Open
Abstract
Accumulating evidence of glutamatergic abnormalities in the brains of schizophrenia patients has led to efforts to target various components of glutamatergic signaling as potential new approaches for schizophrenia. Exciting research suggests that metabotropic glutamate (mGlu) receptors could provide a fundamentally new approach for better symptomatic relief in schizophrenia patients. In preclinical studies, the mGlu5 receptor positive allosteric modulators (PAMs) have efficacy in animal models relevant for all symptom domains in schizophrenia. Interestingly, biased pure mGlu5 receptor PAMs that do not potentiate coupling of mGlu5 receptors to NMDA receptors lack neurotoxic effects associated with mGlu5 PAMs that enhance coupling to N-methyl-D-aspartate (NMDA) receptors or have allosteric agonist activity (ago-PAMs). This provides a better therapeutic profile for treating schizophrenia-like symptoms. Additionally, the mGlu1 receptor PAMs modulate dopamine release in the striatum, which may contribute to their antipsychotic-like effects. Besides group I mGlu (mGlu1 and mGlu5) receptors, agonists of mGlu2/3 receptor also induce robust antipsychotic-like and pro-cognitive effects in rodents and may be effective in treating symptoms of schizophrenia in a selective group of patients. Additionally, mGlu2/4 receptor heterodimers modulate glutamatergic neurotransmission in the prefrontal cortex at selective synapses activated in schizophrenia and, therefore, hold potential as novel antipsychotics. Excitingly, the mGlu3 receptor activation can enhance cognition in rodents suggesting that mGlu3 receptor agonist/PAM could provide a novel approach for the treatment of cognitive deficits in schizophrenia. Collectively, the development of mGlu receptor-specific ligands may provide an alternative approach to meet the clinical need for safer and efficacious therapeutics for schizophrenia. Significance Statement The currently available antipsychotic medications do not show significant efficacy for treating negative symptoms and cognitive deficits in schizophrenia. Emerging preclinical and clinical literature suggests that pharmacological targeting of metabotropic glutamate receptors could potentially provide an alternative approach for designing safer and efficacious therapeutics for treating schizophrenia.
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Zhu X, Grace AA. Use of prepubertal environment enrichment to prevent dopamine dysregulation in a neurodevelopmental rat model of schizophrenia risk. STAR Protoc 2022; 3:101215. [PMID: 35265862 PMCID: PMC8899041 DOI: 10.1016/j.xpro.2022.101215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Here, we present a protocol for delivering environmental enrichment (EE) in discrete postnatal windows to prevent long-term dopamine neuron dysfunctions in a neurodevelopmental rat model of schizophrenia risk. We describe generation of the schizophrenia model through prenatal treatment of rats with methylazoxymethanol acetate (the MAM model) and the saline-treated controls. We then detail the 10-day or 20-day EE paradigms applied on male rats at different ages. This protocol also includes preparation of control groups in regular environment (RE) cages for comparison. For complete details on the use and execution of this protocol, please refer to Zhu and Grace (2021). Protocol to deliver EE in postnatal windows of a rat model of schizophrenia risk Detailed description of supplies and procedures to construct EE boxes Details of animal loading/offloading, cage maintenance, and design of control groups Expected electrophysiological outcomes and troubleshooting of common pitfalls
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Dwir D, Cabungcal JH, Xin L, Giangreco B, Parietti E, Cleusix M, Jenni R, Klauser P, Conus P, Cuénod M, Steullet P, Do KQ. Timely N-Acetyl-Cysteine and Environmental Enrichment Rescue Oxidative Stress-Induced Parvalbumin Interneuron Impairments via MMP9/RAGE Pathway: A Translational Approach for Early Intervention in Psychosis. Schizophr Bull 2021; 47:1782-1794. [PMID: 34080015 PMCID: PMC8530393 DOI: 10.1093/schbul/sbab066] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Research in schizophrenia (SZ) emphasizes the need for new therapeutic approaches based on antioxidant/anti-inflammatory compounds and psycho-social therapy. A hallmark of SZ is a dysfunction of parvalbumin-expressing fast-spiking interneurons (PVI), which are essential for neuronal synchrony during sensory/cognitive processing. Oxidative stress and inflammation during early brain development, as observed in SZ, affect PVI maturation. We compared the efficacy of N-acetyl-cysteine (NAC) and/or environmental enrichment (EE) provided during juvenile and/or adolescent periods in rescuing PVI impairments induced by an additional oxidative insult during childhood in a transgenic mouse model with gluthation deficit (Gclm KO), relevant for SZ. We tested whether this rescue was promoted by the inhibition of MMP9/RAGE mechanism, both in the mouse model and in early psychosis (EP) patients, enrolled in a double-blind, randomized, placebo-controlled clinical trial of NAC supplementation for 6 months. We show that a sequential combination of NAC+EE applied after an early-life oxidative insult recovers integrity and function of PVI network in adult Gclm KO, via the inhibition of MMP9/RAGE. Six-month NAC treatment in EP patients reduces plasma sRAGE in association with increased prefrontal GABA, improvement of cognition and clinical symptoms, suggesting similar neuroprotective mechanisms. The sequential combination of NAC+EE reverses long-lasting effects of an early oxidative insult on PVI/perineuronal net (PNN) through the inhibition of MMP9/RAGE mechanism. In analogy, patients vulnerable to early-life insults could benefit from a combined pharmacological and psycho-social therapy.
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Affiliation(s)
- Daniella Dwir
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Jan-Harry Cabungcal
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Lijing Xin
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Basilio Giangreco
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Enea Parietti
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Martine Cleusix
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
- Service of General Psychiatry, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Raoul Jenni
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
- Service of General Psychiatry, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Paul Klauser
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
- Service of General Psychiatry, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Philippe Conus
- Service of General Psychiatry, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Michel Cuénod
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Pascal Steullet
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Kim Q Do
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
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Clipperton-Allen AE, Zhang A, Cohen OS, Page DT. Environmental Enrichment Rescues Social Behavioral Deficits and Synaptic Abnormalities in Pten Haploinsufficient Mice. Genes (Basel) 2021; 12:1366. [PMID: 34573348 PMCID: PMC8468545 DOI: 10.3390/genes12091366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/20/2021] [Accepted: 08/26/2021] [Indexed: 01/16/2023] Open
Abstract
Pten germline haploinsufficient (Pten+/-) mice, which model macrocephaly/autism syndrome, show social and repetitive behavior deficits, early brain overgrowth, and cortical-subcortical hyperconnectivity. Previous work indicated that altered neuronal connectivity may be a substrate for behavioral deficits. We hypothesized that exposing Pten+/- mice to environmental enrichment after brain overgrowth has occurred may facilitate adaptation to abnormal "hard-wired" connectivity through enhancing synaptic plasticity. Thus, we reared Pten+/- mice and their wild-type littermates from weaning under either standard (4-5 mice per standard-sized cage, containing only bedding and nestlet) or enriched (9-10 mice per large-sized cage, containing objects for exploration and a running wheel, plus bedding and nestlet) conditions. Adult mice were tested on social and non-social assays in which Pten+/- mice display deficits. Environmental enrichment rescued sex-specific deficits in social behavior in Pten+/- mice and partially rescued increased repetitive behavior in Pten+/- males. We found that Pten+/- mice show increased excitatory and decreased inhibitory pre-synaptic proteins; this phenotype was also rescued by environmental enrichment. Together, our results indicate that environmental enrichment can rescue social behavioral deficits in Pten+/- mice, possibly through normalizing the excitatory synaptic protein abundance.
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Affiliation(s)
| | | | | | - Damon Theron Page
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; (A.E.C.-A.); (A.Z.); (O.S.C.)
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13
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Huang Y, Jiang H, Zheng Q, Fok AHK, Li X, Lau CG, Lai CSW. Environmental enrichment or selective activation of parvalbumin-expressing interneurons ameliorates synaptic and behavioral deficits in animal models with schizophrenia-like behaviors during adolescence. Mol Psychiatry 2021; 26:2533-2552. [PMID: 33473150 DOI: 10.1038/s41380-020-01005-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/18/2022]
Abstract
Synaptic deficit-induced excitation and inhibition (E/I) imbalance have been implicated in the pathogenesis of schizophrenia. Using in vivo two-photon microscopy, we examined the dynamic plasticity of dendritic spines of pyramidal neurons (PNs) and "en passant" axonal bouton of parvalbumin-expressing interneurons (PVINs) in the frontal association (FrA) cortex in two adolescent mouse models with schizophrenia-like behaviors. Simultaneous imaging of PN dendritic spines and PV axonal boutons showed that repeated exposure to N-methyl-D-aspartate receptor (NMDAR) antagonist MK801 during adolescence disrupted the normal developmental balance of excitatory and inhibitory synaptic structures. This MK801-induced structural E/I imbalance significantly correlated with animal recognition memory deficits and could be ameliorated by environmental enrichment (EE). In addition, selective chemogenetic activation of PVINs in the FrA mimicked the effects of EE on both synaptic plasticity and animal behavior, while selective inhibition of PVIN abolished EE's beneficial effects. Electrophysiological recordings showed that chronic MK801 treatment significantly suppressed the frequency of mEPSC/mIPSC ratio of layer (L) 2/3 PNs and significantly reduced the resting membrane potential of PVINs, the latter was rescued by selective activation of PVINs. Such manipulations of PVINs also showed similar effects in PV-Cre; ErbB4fl/fl animal model with schizophrenia-like behaviors. EE or selective activation of PVINs in the FrA restored behavioral deficits and structural E/I imbalance in adolescent PV-Cre; ErbB4fl/fl mice, while selective inhibition of PVINs abolished EE's beneficial effects. Our findings suggest that the PVIN activity in the FrA plays a crucial role in regulating excitatory and inhibitory synaptic structural dynamics and animal behaviors, which may provide a potential therapeutic target for schizophrenia treatment.
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Affiliation(s)
- Yuhua Huang
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Hehai Jiang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong.,Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Qiyu Zheng
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Albert Hiu Ka Fok
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Xiaoyang Li
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - C Geoffrey Lau
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong.,Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Cora Sau Wan Lai
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong. .,State Key Laboratory of Cognitive and Brain Research, The University of Hong Kong, Pokfulam, Hong Kong.
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14
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Zhu X, Grace AA. Prepubertal Environmental Enrichment Prevents Dopamine Dysregulation and Hippocampal Hyperactivity in MAM Schizophrenia Model Rats. Biol Psychiatry 2021; 89:298-307. [PMID: 33357630 PMCID: PMC7927755 DOI: 10.1016/j.biopsych.2020.09.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 09/07/2020] [Accepted: 09/20/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Schizophrenia (SCZ) is a neurodevelopmental disorder with a progressive, prolonged course. Early prevention for SCZ is promising but overall lacks support from preclinical evidence. Previous studies have tested environmental enrichment (EE) in certain models of SCZ and discovered a broadly beneficial effect in preventing behavioral abnormalities relevant, yet not specific, to the disorder. Nonetheless, whether EE can prevent dopamine (DA) dysregulation, a hallmark of psychosis and SCZ, had not been tested. METHODS Using the MAM (methylazoxymethanol acetate) rat model of schizophrenia and saline-treated control animals, we investigated the long-term electrophysiological effects of prepubertal (postnatal day 21-40) EE on DA neurons, pyramidal neurons in the ventral hippocampus, and projection neurons in the basolateral amygdala. Anxiety-related behaviors in the elevated plus maze and locomotor responses to amphetamine were also analyzed. RESULTS Prepubertal EE prevented the increased population activity of DA neurons and the associated increase in locomotor response to amphetamine. Prepubertal EE also prevented hyperactivity in the ventral hippocampus but did not prevent hyperactivity in the basolateral amygdala. Anxiety-like behaviors in MAM rats were not ameliorated by prepubertal exposure to EE. CONCLUSIONS Twenty-day prepubertal EE is sufficient to prevent DA hyperresponsivity in the MAM model, measured by electrophysiological recordings and locomotor response to amphetamine. This effect is potentially mediated by normalizing excessive firing in the ventral hippocampus without affecting anxiety-like behaviors and basolateral amygdala firing. This study identified EE as a useful preventative approach that may protect against the pathophysiological development of SCZ.
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Affiliation(s)
- Xiyu Zhu
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania.
| | - Anthony A Grace
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania
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15
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Ang MJ, Lee S, Kim JC, Kim SH, Moon C. Behavioral Tasks Evaluating Schizophrenia-like Symptoms in Animal Models: A Recent Update. Curr Neuropharmacol 2021; 19:641-664. [PMID: 32798374 PMCID: PMC8573744 DOI: 10.2174/1570159x18666200814175114] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/23/2020] [Accepted: 07/31/2020] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Schizophrenia is a serious mental illness that affects more than 21 million people worldwide. Both genetics and the environment play a role in its etiology and pathogenesis. Symptoms of schizophrenia are mainly categorized into positive, negative, and cognitive. One major approach to identify and understand these diverse symptoms in humans has been to study behavioral phenotypes in a range of animal models of schizophrenia. OBJECTIVE We aimed to provide a comprehensive review of the behavioral tasks commonly used for measuring schizophrenia-like behaviors in rodents together with an update of the recent study findings. METHODS Articles describing phenotypes of schizophrenia-like behaviors in various animal models were collected through a literature search in Google Scholar, PubMed, Web of Science, and Scopus, with a focus on advances over the last 10 years. RESULTS Numerous studies have used a range of animal models and behavioral paradigms of schizophrenia to develop antipsychotic drugs for improved therapeutics. In establishing animal models of schizophrenia, the candidate models were evaluated for schizophrenia-like behaviors using several behavioral tasks for positive, negative, and cognitive symptoms designed to verify human symptoms of schizophrenia. Such validated animal models were provided as rapid preclinical avenues for drug testing and mechanistic studies. CONCLUSION Based on the most recent advances in the field, it is apparent that a myriad of behavior tests are needed to confirm and evaluate the congruency of animal models with the numerous behaviors and clinical signs exhibited by patients with schizophrenia.
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Affiliation(s)
| | | | | | | | - Changjong Moon
- Address correspondence to this author at the Department of Veterinary Anatomy and Animal Behavior, College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea, Tel: +82-62-530-2838; E-mail:
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16
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Koizumi H, Hiraga T, Oharomari LK, Hata T, Shima T, Yook JS, Okamoto M, Mouri A, Nabeshima T, Soya H. Preventive role of regular low-intensity exercise during adolescence in schizophrenia model mice with abnormal behaviors. Biochem Biophys Res Commun 2020; 534:610-616. [PMID: 33228965 DOI: 10.1016/j.bbrc.2020.11.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
Schizophrenia is probably ascribed to perinatal neurodevelopmental deficits, and its onset might be affected by environmental factors. Hypofrontality with glutamatergic and dopaminergic neuronal dysfunction are known factors, but a way to mitigate abnormalities remains unfound. An early enriched environment such as a wheel running in rodents may contribute to the prevention, but its clinical applicability is very limited. From our studies, low-intensity exercise training (LET) based on physiological indices, such as lactate threshold, easily translates to humans and positively affects the brains. Hence, LET during adolescence may ameliorate abnormalities in neurodevelopment and prevent the development of schizophrenia. In the current study, LET prevented sensitization to phencyclidine (PCP) treatment, impairment of cognition, and affective behavioral abnormalities in an animal model of schizophrenia induced by prenatal PCP treatment. Further, LET increased dopamine turnover and attenuated the impairment of phosphorylation of ERK1/2 after exposure to a novel object in the prenatal PCP-treated mice. These results suggest that LET during adolescence completely improves schizophrenia-like abnormal behaviors associated with improved glutamate uptake and the dopamine-induced ERK1/2 signaling pathway in the PFC.
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Affiliation(s)
- Hikaru Koizumi
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Taichi Hiraga
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Leandro K Oharomari
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Toshiaki Hata
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Takeru Shima
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Jang Soo Yook
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Masahiro Okamoto
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Akihiro Mouri
- Advanced Diagnostic System Research Laboratory, Fujita Health University, Graduate School of Health Sciences, Toyoake, 470-1192, Aichi, Japan; Department of Regulatory Science for Evaluation and Development of Pharmaceuticals and Devices, Fujita Health University, Graduate School of Health Sciences, Toyoake, 470-1192, Aichi, Japan
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University, Graduate School of Health Sciences, Toyoake, 470-1192, Aichi, Japan
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan.
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17
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Gubert C, Kong G, Uzungil V, Zeleznikow-Johnston AM, Burrows EL, Renoir T, Hannan AJ. Microbiome Profiling Reveals Gut Dysbiosis in the Metabotropic Glutamate Receptor 5 Knockout Mouse Model of Schizophrenia. Front Cell Dev Biol 2020; 8:582320. [PMID: 33195226 PMCID: PMC7658610 DOI: 10.3389/fcell.2020.582320] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 10/08/2020] [Indexed: 01/03/2023] Open
Abstract
Schizophrenia (SZ) is a psychiatric disorder that constitutes one of the top 10 global causes of disability. More recently, a potential pathogenic role for the gut microbial community (microbiota) has been highlighted, with numerous studies describing dysregulated microbial profiles in SZ patients when compared to healthy controls. However, no animal model of SZ has previously recapitulated the gut dysbiosis observed clinically. Since the metabotropic glutamate receptor 5 (mGlu5) knockout mice provide a preclinical model of SZ with strong face and predictive validity, in the present study we performed gut microbiome profiling of mGlu5 knockout (KO) and wild-type (WT) mice by 16S rRNA sequencing of bacterial genomic DNA from fecal samples, analyzing bacterial diversity and taxonomic composition, as well as gastrointestinal parameters as indicators of gut function. We found a significant genotype difference in microbial beta diversity. Analysis of composition of microbiomes (ANCOM) models were performed to evaluate microbiota compositions, which identified a decreased relative abundance of the Erysipelotrichaceae family and Allobaculum genus in this mouse model of SZ. We also identified a signature of bacteria discriminating between the genotypes (KO and WT), consisting of the Erysipelotrichales, Bacteroidales, and Clostridiales orders and macroscopic gut differences. We thus uncovered global differential community composition in the gut microbiota profile between mGlu5 KO and WT mice, outlining the first evidence for gut dysbiosis in a genetic animal model of SZ. Our findings suggest that this widely used preclinical model of SZ also has substantial utility for investigations of gut dysbiosis and associated signaling via the microbiota-gut-brain axis, as potential modulators of SZ pathogenesis. Our discovery opens up new avenues to explore gut dysbiosis and its proposed links to brain dysfunction in SZ, as well as novel therapeutic approaches to this devastating disorder.
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Affiliation(s)
- Carolina Gubert
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Geraldine Kong
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Volkan Uzungil
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | | | - Emma L. Burrows
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Anthony J. Hannan
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
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18
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Zhou T, Lin L, Hao C, Liao W. Environmental enrichment rescues cognitive impairment with suppression of TLR4-p38MAPK signaling pathway in vascular dementia rats. Neurosci Lett 2020; 737:135318. [PMID: 32846221 DOI: 10.1016/j.neulet.2020.135318] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 01/23/2023]
Abstract
Increasing evidence demonstrated the promising effects of environmental enrichment (EE) on brain recovery and cognitive performance in animal models of various diseases. However, the effect and molecular mechanisms of EE on vascular dementia (VD) remain to be studied. The aim of this study was to explore the effect of EE on cognitive decline and its mechanism. Sprague-Dawley rats underwent 2-vessel occlusion (2-VO) surgery or sham operation. Subsequently, rats were kept in EE for 4 weeks. In Morris water maze (MWM) test, we demonstrated that EE significantly improved cognitive function in rats with VD. HE staining exhibited morphological changes of neurons and quantitative analysis of TUNEL showed increased apoptotic neurons in hippocampal CA1 region following 2-VO. Results from RT-qPCR showed up-regulation of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) after 2-VO. Western blotting analysis revealed enhanced toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MYD88) and phosphorylated p38 mitogen-activated protein kinase (p-p38MAPK) in 2-VO rats. Whereas administration of EE reduced apoptotic neurons, down-regulated inflammatory factors. Moreover, EE suppressed protein expression of TLR4-p38MAPK pathway. Spearman correlation analysis showed that improved cognitive function was associated with decreased expression of TLR4 and p-p38MAPK proteins. Thus, our study proved that EE has a prominent effect on cognitive impairment and neuronal damage following 2-VO by attenuating inflammation and apoptosis, which may be realized via inhibiting the TLR4-P38MAPK signaling pathway.
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Affiliation(s)
- Tiantian Zhou
- Departmenta of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Lu Lin
- Departmenta of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Chizi Hao
- Departmenta of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Weijing Liao
- Departmenta of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
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Singhal G, Morgan J, Jawahar MC, Corrigan F, Jaehne EJ, Toben C, Manavis J, Hannan AJ, Baune BT. Duration of Environmental Enrichment Determines Astrocyte Number and Cervical Lymph Node T Lymphocyte Proportions but Not the Microglial Number in Middle-Aged C57BL/6 Mice. Front Cell Neurosci 2020; 14:57. [PMID: 32256319 PMCID: PMC7094170 DOI: 10.3389/fncel.2020.00057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/27/2020] [Indexed: 11/13/2022] Open
Abstract
Environmental enrichment (EE) has been shown to modulate behavior and immunity. We recently reported that both short and long-term EE enhance baseline locomotion and alleviate depressive-like behavior, but only long-term EE affects locomotion adversely in a threatening environment and enhances anxiety-like behavior in middle-age mice. We have now investigated whether the observed changes in behavior after short- and long-term EE were associated with underlying immune changes. Hence, at the end of behavioral testing, mice were sacrificed, and brains and cervical lymph nodes were collected to investigate the differential effects of the duration of EE (short- and long-term) on the number of immunopositive glial cells in the dentate gyrus, CA1, CA2, and CA3 regions of the hippocampus and proportions of T cell subsets in the cervical lymph nodes using immunohistochemistry and flow cytometry, respectively. EE, regardless of duration, caused an increase in microglia number within the dentate gyrus, CA1 and CA3 hippocampal regions, but only long-term EE increased astrocytes number within the dentate gyrus and CA3 hippocampal regions. A significantly higher proportion of CD8+ naive T cells was observed after long-term EE vs. short-term EE. No significant differences were observed in the proportion of central memory and effector memory T cells or early activated CD25+ cells between any of the test groups. Our results suggest that EE, irrespective of duration, enhances the numbers of microglia, but long-term EE is required to modify astrocyte number and peripheral T cell proportions in middle-aged mice. Our findings provide new insights into the therapeutic effects of EE on various brain disorders, which may be at least partly mediated by glial and neuroimmune modulation.
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Affiliation(s)
- Gaurav Singhal
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia
| | - Julie Morgan
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia
| | - Magdalene C Jawahar
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia
| | - Frances Corrigan
- Division of Health Sciences, The University of South Australia, Adelaide, SA, Australia
| | - Emily J Jaehne
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia.,School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Catherine Toben
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia
| | - Jim Manavis
- Faculty of Health, Centre for Neurological Diseases, School of Medicine, The University of Adelaide, Adelaide, SA, Australia
| | - Anthony J Hannan
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Bernhard T Baune
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia.,Department of Psychiatry, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia.,Department of Psychiatry, University of Münster, Münster, Germany
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20
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Wilson C, Li S, Hannan AJ, Renoir T. Antidepressant-like effects of ketamine in a mouse model of serotonergic dysfunction. Neuropharmacology 2020; 168:107998. [PMID: 32061666 DOI: 10.1016/j.neuropharm.2020.107998] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 02/05/2020] [Accepted: 02/09/2020] [Indexed: 12/28/2022]
Abstract
Traditional monoaminergic treatments of depression frequently exhibit suboptimal tolerability and effectiveness. The 'short' (s) allele variant of 5-HTTLPR is known to compromise transcriptional efficacy of the serotonin transporter (5-HTT) and can reduce treatment response to traditional antidepressants (e.g. selective serotonin reuptake inhibitors or SSRIs). This study sought to establish the 5-HTT knock-out (KO) line as a mouse model of SSRI-resistant depression and assess its response to a novel glutamatergic antidepressant, ketamine, a non-competitive N-methyl-d-aspartate receptor (NMDAR) antagonist. Following acute antidepressant treatment, 5-HTT KO mice and wild-type (WT) controls were subjected to the forced-swim test (FST), one of the most widely used techniques to detect acute antidepressant response. As hypothesised, when assessed 30 min after administration in the FST, the SSRI sertraline (20 mg/kg, i.p.) produced antidepressant-like effects in WT control but not in 5-HTT KO mice. In contrast, ketamine (20 mg/kg, i.p.) induced antidepressant-like effects in both genotypes. 5-HTT KO mice also exhibited a reduced locomotor response to both MK-801 (another NMDAR antagonist) and ketamine, and reduced GluN2A protein levels in the hippocampus, suggesting glutamatergic dysfunction in this model. These results highlight the utility of 5-HTT KO mice as a relevant model of SSRI-resistant depression and demonstrate that ketamine can produce acute antidepressant-like effects in conditions of 5-HTT deficiency. These findings extend existing literature that indicates ketamine is effective in ameliorating symptoms of treatment-resistant depression and may have implications for understanding the cellular and molecular mechanisms underlying the antidepressant effects of ketamine. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.
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Affiliation(s)
- Carey Wilson
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Melbourne School of Psychological Science, University of Melbourne, Parkville, Australia
| | - Shanshan Li
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Facssulty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia.
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Murueta-Goyena A, Ortuzar N, Lafuente JV, Bengoetxea H. Enriched Environment Reverts Somatostatin Interneuron Loss in MK-801 Model of Schizophrenia. Mol Neurobiol 2019; 57:125-134. [PMID: 31506899 DOI: 10.1007/s12035-019-01762-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 08/29/2019] [Indexed: 02/02/2023]
Abstract
Dysregulation of the inhibitory drive has been proposed to be a central mechanism to explain symptoms and pathophysiological hallmarks in schizophrenia. A number of recent neuroanatomical studies suggest that certain types of inhibitory cells are deficient in schizophrenia, including somatostatin-immunoreactive interneurons (SST+). The present study sought to use stereological methods to investigate whether the number of SST+ interneurons decreased after repeated injections of NMDA receptor antagonist MK-801 (0.5 mg/kg) and to determine the effect of limited exposure to an enriched environment (EE) in adult life on this sub-population of inhibitory cells. Considering that somatostatin expression is highly dependent on neurotrophic support, we explored the changes in the relative expression of proteins related to brain-derived neurotrophic factor-tyrosine kinase B (BDNF-TrkB) signaling between the experimental groups. We observed that early-life MK-801 treatment significantly decreased the number of SST+ interneurons in the medial prefrontal cortex (mPFC) and the hippocampus (HPC) of adult Long Evans rats. Contrarily, short-term exposure to EE increased the number of SST+ interneurons in MK-801-injected animals, except in the CA1 region of the hippocampus, whereas this increase was not observed in vehicle-injected rats. We also found upregulated BDNF-TrkB signaling after EE that triggered an increase in the pERK/ERK ratio in mPFC and HPC, and the pAkt/Akt ratio in HPC. Thus, the present results support the notion that SST+ interneurons are markedly affected after early-life NMDAR blockade and that EE promotes SST+ interneuron expression, which is partly mediated through the BDNF-TrkB signaling pathway. These results may have important implications for schizophrenia, as SST+ interneuron loss is also observed in the MK-801 pre-clinical model, and its expression can be rescued by non-pharmacological approaches.
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Affiliation(s)
- Ane Murueta-Goyena
- Laboratory of Clinical and Experimental Neuroscience, Department of Neuroscience, University of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain. .,Neurodegenerative Diseases group, BioCruces Bizkaia Health Research Institute, Plaza de Cruces 12, 48903, Barakaldo, Bizkaia, Spain.
| | - Naiara Ortuzar
- Laboratory of Clinical and Experimental Neuroscience, Department of Neuroscience, University of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain
| | - José Vicente Lafuente
- Laboratory of Clinical and Experimental Neuroscience, Department of Neuroscience, University of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain.,Nanoneurosurgery Group, BioCruces Bizkaia Health Research Institute, Plaza de Cruces 12, 48903, Barakaldo, Bizkaia, Spain
| | - Harkaitz Bengoetxea
- Laboratory of Clinical and Experimental Neuroscience, Department of Neuroscience, University of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain
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Singhal G, Morgan J, Jawahar MC, Corrigan F, Jaehne EJ, Toben C, Breen J, Pederson SM, Hannan AJ, Baune BT. The effects of short-term and long-term environmental enrichment on locomotion, mood-like behavior, cognition and hippocampal gene expression. Behav Brain Res 2019; 368:111917. [DOI: 10.1016/j.bbr.2019.111917] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 02/07/2023]
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Huang X, Wang M, Zhang Q, Chen X, Wu J. The role of glutamate receptors in attention-deficit/hyperactivity disorder: From physiology to disease. Am J Med Genet B Neuropsychiatr Genet 2019; 180:272-286. [PMID: 30953404 DOI: 10.1002/ajmg.b.32726] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/12/2019] [Accepted: 03/19/2019] [Indexed: 12/15/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is the most common psychiatric disorder in children and adolescents, which is characterized by behavioral problems such as attention deficit, hyperactivity, and impulsivity. As the receptors of the major excitatory neurotransmitter in the mammalian central nervous system (CNS), glutamate receptors (GluRs) are strongly linked to normal brain functioning and pathological processes. Extensive investigations have been made about the structure, function, and regulation of GluR family, describing evidences that support the disruption of these mechanisms in mental disorders, including ADHD. In this review, we briefly described the family and function of GluRs in the CNS, and discussed what is recently known about the role of GluRs in ADHD, that including GluR genes, animal models, and the treatment, which would help us further elucidate the etiology of ADHD.
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Affiliation(s)
- Xin Huang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Min Wang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi Zhang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinzhen Chen
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Wu
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Murueta-Goyena A, Morera-Herreras T, Miguelez C, Gutiérrez-Ceballos A, Ugedo L, Lafuente JV, Bengoetxea H. Effects of adult enriched environment on cognition, hippocampal-prefrontal plasticity and NMDAR subunit expression in MK-801-induced schizophrenia model. Eur Neuropsychopharmacol 2019; 29:590-600. [PMID: 30926324 DOI: 10.1016/j.euroneuro.2019.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 03/13/2019] [Accepted: 03/13/2019] [Indexed: 11/30/2022]
Abstract
Schizophrenia is a mental disorder characterized by psychosis, negative symptoms and cognitive impairment. Cognitive deficits are enduring and represent the most disabling symptom but are currently poorly treated. N-methyl D-aspartate receptor (NMDAR) hypofunction hypothesis has been notably successful in explaining the pathophysiological findings and symptomatology of schizophrenia. Thereby, NMDAR blockade in rodents represents a useful tool to identify new therapeutic approaches. In this regard, enriched environment (EE) could play an essential role. Using a multilevel approach of behavior, electrophysiology and protein analysis, we showed that a short-term exposure to EE in adulthood ameliorated spatial learning and object-place associative memory impairment observed in postnatally MK-801-treated Long Evans rats. Moreover, EE in adult life restored long-term potentiation (LTP) in hippocampal-medial prefrontal pathway abolished by MK-801 treatment. EE in adulthood also induced a set of modifications in the expression of proteins related to glutamatergic neurotransmission. Taken together, these findings shed new light on the neurobiological effects of EE to reverse the actions of MK-801 and offer a preclinical testing of a therapeutic strategy that may be remarkably effective for managing cognitive symptoms of schizophrenia.
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Affiliation(s)
- Ane Murueta-Goyena
- Deparment of Neuroscience, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Bizkaia, Spain; Neurodegenerative Diseases group, BioCruces Bizkaia Health Research Institute, Barakaldo, Spain.
| | - Teresa Morera-Herreras
- Deparment of Pharmacology, University of the Basque Country (UPV/EHU), Leioa, Spain; Neurodegenerative Diseases group, BioCruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Cristina Miguelez
- Deparment of Pharmacology, University of the Basque Country (UPV/EHU), Leioa, Spain; Neurodegenerative Diseases group, BioCruces Bizkaia Health Research Institute, Barakaldo, Spain
| | | | - Luisa Ugedo
- Deparment of Pharmacology, University of the Basque Country (UPV/EHU), Leioa, Spain; Neurodegenerative Diseases group, BioCruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - José Vicente Lafuente
- Deparment of Neuroscience, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Bizkaia, Spain; Nanoneurosurgery Group, BioCruces Bizkaia Health Research Institute, Barakaldo, Spain; Faculty of Health Science, Universidad Autónoma de Chile, Santiago de Chile, Chile
| | - Harkaitz Bengoetxea
- Deparment of Neuroscience, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Bizkaia, Spain
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25
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Liu E, Zhou Q, Xie AJ, Li M, Zhang S, Huang H, Liuyang Z, Wang Y, Liu B, Li X, Sun D, Wei Y, Wang X, Wang Q, Ke D, Yang X, Yang Y, Wang JZ. Enriched gestation activates the IGF pathway to evoke embryo-adult benefits to prevent Alzheimer's disease. Transl Neurodegener 2019; 8:8. [PMID: 30867903 PMCID: PMC6399936 DOI: 10.1186/s40035-019-0149-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 02/15/2019] [Indexed: 12/13/2022] Open
Abstract
Background Building brain reserves before dementia onset could represent a promising strategy to prevent Alzheimer's disease (AD), while how to initiate early cognitive stimulation is unclear. Given that the immature brain is more sensitive to environmental stimuli and that brain dynamics decrease with ageing, we reasoned that it would be effective to initiate cognitive stimulation against AD as early as the fetal period. Methods After conception, maternal AD transgenic mice (3 × Tg AD) were exposed to gestational environment enrichment (GEE) until the day of delivery. The cognitive capacity of the offspring was assessed by the Morris water maze and contextual fear-conditioning tests when the offspring were raised in a standard environment to 7 months of age. Western blotting, immunohistochemistry, real-time PCR, immunoprecipitation, chromatin immunoprecipitation (ChIP) assay, electrophysiology, Golgi staining, activity assays and sandwich ELISA were employed to gain insight into the mechanisms underlying the beneficial effects of GEE on embryos and 7-10-month-old adult offspring. Results We found that GEE markedly preserved synaptic plasticity and memory capacity with amelioration of hallmark pathologies in 7-10-m-old AD offspring. The beneficial effects of GEE were accompanied by global histone hyperacetylation, including those at bdnf promoter-binding regions, with robust BDNF mRNA and protein expression in both embryo and progeny hippocampus. GEE increased insulin-like growth factor 1 (IGF1) and activated its receptor (IGF1R), which phosphorylates Ca2+/calmodulin-dependent kinase IV (CaMKIV) at tyrosine sites and triggers its nuclear translocation, subsequently upregulating histone acetyltransferase (HAT) and BDNF transcription. The upregulation of IGF1 mimicked the effects of GEE, while IGF1R or HAT inhibition during pregnancy abolished the GEE-induced CaMKIV-dependent histone hyperacetylation and BDNF upregulation. Conclusions These findings suggest that activation of IGF1R/CaMKIV/HAT/BDNF signaling by gestational environment enrichment may serve as a promising strategy to delay AD progression.
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Affiliation(s)
- Enjie Liu
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China.,4Department of Pathology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Qiuzhi Zhou
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Ao-Ji Xie
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Mengzhu Li
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Shujuan Zhang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Hezhou Huang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Zhenyu Liuyang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Yali Wang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Bingjin Liu
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Xiaoguang Li
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Dongsheng Sun
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Yuping Wei
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Xiaochuan Wang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Qun Wang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Dan Ke
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Xifei Yang
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Centre for Disease Control and Prevention, 8 Longyuan Road, Shenzhen, 518055 China
| | - Ying Yang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
| | - Jian-Zhi Wang
- 1Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China.,2Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226000 China
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Llorens-Martín M. Exercising New Neurons to Vanquish Alzheimer Disease. Brain Plast 2018; 4:111-126. [PMID: 30564550 PMCID: PMC6296267 DOI: 10.3233/bpl-180065] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Alzheimer disease (AD) is the most common type of dementia in individuals over 65 years of age. The neuropathological hallmarks of the condition are Tau neurofibrillary tangles and Amyloid-β senile plaques. Moreover, certain susceptible regions of the brain experience a generalized lack of neural plasticity and marked synaptic alterations during the progression of this as yet incurable disease. One of these regions, the hippocampus, is characterized by the continuous addition of new neurons throughout life. This phenomenon, named adult hippocampal neurogenesis (AHN), provides a potentially endless source of new synaptic elements that increase the complexity and plasticity of the hippocampal circuitry. Numerous lines of evidence show that physical activity and environmental enrichment (EE) are among the most potent positive regulators of AHN. Given that neural plasticity is markedly decreased in many neurodegenerative diseases, the therapeutic potential of making certain lifestyle changes, such as increasing physical activity, is being recognised in several non-pharmacologic strategies seeking to slow down or prevent the progression of these diseases. This review article summarizes current evidence supporting the putative therapeutic potential of EE and physical exercise to increase AHN and hippocampal plasticity both under physiological and pathological circumstances, with a special emphasis on neurodegenerative diseases and AD.
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Affiliation(s)
- María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSIC-UAM, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases CIBERNED, Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
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Zeleznikow-Johnston AM, Renoir T, Churilov L, Li S, Burrows EL, Hannan AJ. Touchscreen testing reveals clinically relevant cognitive abnormalities in a mouse model of schizophrenia lacking metabotropic glutamate receptor 5. Sci Rep 2018; 8:16412. [PMID: 30401923 PMCID: PMC6219561 DOI: 10.1038/s41598-018-33929-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/08/2018] [Indexed: 11/09/2022] Open
Abstract
Metabotropic glutamate receptor 5 (mGlu5) has been implicated in certain forms of synaptic plasticity and cognitive function. mGlu5 knockout (KO) mice and mGlu5 antagonists have been previously used to study the pathophysiology of schizophrenia as they have been shown respectively to display or induce endophenotypes relevant to schizophrenia. While schizophrenia presents with generalized cognitive impairments, the cognitive phenotype of mice lacking mGlu5 has so far only been explored using largely hippocampal-dependent spatial and contextual memory tasks. To address this, we used a touchscreen system to assess mGlu5 KO mice for pairwise visual discrimination, reversal learning, and extinction of an instrumental response requiring no discrimination. Furthermore, we tested the role of mGlu5 in working memory using the Trial-Unique Non-Matching to Location (TUNL) task utilizing pharmacological ablation. mGlu5 KO mice were impaired on discrimination learning, taking longer to reach criterion and requiring more correction learning trials. Performance on reversal learning was also impaired, with mGlu5 KO mice demonstrating a perseverative phenotype. The mGlu5 KO mice responded at a higher rate during extinction, consistent with this perseverative profile. In contrast, wildtype mice treated acutely with an mGlu5 antagonist (MTEP) showed no deficits in a touchscreen task assessing working memory. The present study demonstrates learning and memory deficits as well as an increased perseverative phenotype following constitutive loss of mGlu5 in this mouse model of schizophrenia. These findings will inform translational approaches using this preclinical model and the pursuit of mGlu5 as therapeutic target for schizophrenia and other brain disorders.
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Affiliation(s)
- Ariel M Zeleznikow-Johnston
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia
| | - Leonid Churilov
- Florey Institute of Neuroscience and Mental Health, 245 Burgundy St, Heidelberg, Australia
| | - Shanshan Li
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia
| | - Emma L Burrows
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia. .,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Australia.
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Grech AM, Ratnayake U, Hannan AJ, van den Buuse M, Hill RA. Sex-Dependent Effects of Environmental Enrichment on Spatial Memory and Brain-Derived Neurotrophic Factor (BDNF) Signaling in a Developmental "Two-Hit" Mouse Model Combining BDNF Haploinsufficiency and Chronic Glucocorticoid Stimulation. Front Behav Neurosci 2018; 12:227. [PMID: 30356704 PMCID: PMC6189322 DOI: 10.3389/fnbeh.2018.00227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/11/2018] [Indexed: 01/02/2023] Open
Abstract
Neurodevelopmental disorders are thought to be caused by a combination of adverse genetic and environmental insults. The "two-hit" hypothesis suggests that an early first "hit" primes the developing brain to be vulnerable to a second "hit" during adolescence which triggers behavioral dysfunction. We have previously modeled this scenario in mice and found that the combined effect of a genetic hapolinsuffuciency in the brain-derived neurotrophic factor (BDNF) gene (1st hit) and chronic corticosterone (CORT) treatment during adolescence (2nd hit), caused spatial memory impairments in adulthood. Environmental enrichment (EE) protocols are designed to stimulate experience-dependent plasticity and have shown therapeutic actions. This study investigated whether EE can reverse these spatial memory impairments. Wild-type (WT) and BDNF heterozygous (HET) mice were treated with corticosterone (CORT) in their drinking water (50 mg/L) from weeks 6 to 8 and exposed to EE from 7 to 9 weeks. Enriched housing included open top cages with additional toys, tunnels, housing, and platforms. Y-maze novel preference testing, to assess short-term spatial memory, was performed at 10 weeks of age. At week 16 dorsal hippocampus tissue was obtained for Western blot analysis of expression levels of BDNF, the BDNF receptor TrkB, and NMDA receptor subunits, GluNR1, 2A and 2B. As in our previous studies, spatial memory was impaired in our two-hit (BDNF HET + CORT) mice. Simultaneous EE prevented these impairments. However, EE appeared to worsen spatial memory performance in WT mice, particularly those exposed to CORT. While BDNF levels were lower in BDNF HET mice as expected, there were no further effects of CORT or EE in males but a close to significant female CORT × EE × genotype interaction which qualitatively corresponded with Y-maze performance. However, EE caused both sex- and genotype-specific effects on phosphorylated TrkB residues and GluNR expression within the dorsal hippocampus, with GluNR2B levels in males changing in parallel with spatial memory performance. In conclusion, beneficial effects of EE on spatial memory emerge only following two developmental disruptions. The mechanisms by which EE exerts its effects are likely via regulation of multiple activity-dependent pathways, including TrkB and NMDA receptor signaling.
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Affiliation(s)
- Adrienne M. Grech
- Department of Psychiatry, School of Clinical Sciences, Monash Medical Centre, Monash University, Clayton, VIC, Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Udani Ratnayake
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Anthony J. Hannan
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
- Department of Pharmacology, University of Melbourne, Melbourne, VIC, Australia
- The College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Rachel A. Hill
- Department of Psychiatry, School of Clinical Sciences, Monash Medical Centre, Monash University, Clayton, VIC, Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
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29
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Environmental enrichment alleviates cognitive and behavioral impairments in EL mice. Epilepsy Behav 2018; 85:227-233. [PMID: 30032812 DOI: 10.1016/j.yebeh.2018.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/01/2018] [Accepted: 06/01/2018] [Indexed: 01/17/2023]
Abstract
Epilepsy in children is occasionally associated with comorbidities, such as cognitive impairment, behavioral disturbances, and social deficits. These neurobehavioral comorbidities are closely related to environmental factors and the severity of the seizures. Previous studies show that environmental enrichment has a beneficial effect in animal models of temporal lobe epilepsy following systemic chemoconvulsant administration. However, the effect of environmental enrichment on behavioral impairments in the EL mouse, a genetic model of human idiopathic epilepsy, remains unknown. In the present study, we examined the effect of environmental enrichment on cognitive and behavioral impairments in this murine model. The EL mice, under standard laboratory conditions, exhibited impairments in spatial memory in the Morris water maze test, hyperactivity and impaired habituation in the open-field test, and a deficit in social novelty preference in the three-chamber social approach test, compared with control DDY mice, a genetically related nonepileptic strain. These impairments in EL mice were ameliorated by exposure to an enriched environment. These findings suggest that environmental enrichment effectively ameliorates cognitive and behavioral deficits in EL mice.
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30
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Zhou D, Lv D, Wang Z, Zhang Y, Chen Z, Wang C. GLYX-13 Ameliorates Schizophrenia-Like Phenotype Induced by MK-801 in Mice: Role of Hippocampal NR2B and DISC1. Front Mol Neurosci 2018; 11:121. [PMID: 29695955 PMCID: PMC5904356 DOI: 10.3389/fnmol.2018.00121] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 03/28/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Evidence supports that the hypofunction of N-methyl-D-aspartate receptor (NMDAR) and downregulation of disrupted-in-schizophrenia 1 (DISC1) contribute to the pathophysiology of schizophrenia. N-Methyl D-aspartate receptor subtype 2B (NR2B)-containing NMDAR are associated with cognitive dysfunction in schizophrenia. GLYX-13 is an NMDAR glycine-site functional partial agonist and cognitive enhancer that does not induce psychotomimetic side effects. However, it remains unclear whether NR2B plays a critical role in the GLYX-13-induced alleviation of schizophrenia-like behaviors in mice. Methods: The effect of GLYX-13 was tested by observing changes in locomotor activity, novel object recognition ability, and prepulse inhibition (PPI) induced by dizocilpine (known as MK-801) in mice. Lentivirus-mediated NR2B knockdown in the hippocampus was assessed to confirm the role of NR2B in GLYX-13 pathophysiology, using Western blots and immunohistochemistry. Results: The systemic administration of GLYX-13 (0.5 and 1 mg/kg, i.p.) ameliorates MK-801 (0.5 mg/kg, i.p.)-induced hyperlocomotion, deficits in memory, and PPI in mice. Additionally, GLYX-13 normalized the MK-801-induced alterations in signaling molecules, including NR2B and DISC1 in the hippocampus. Furthermore, we found that NR2B knockdown produced memory and PPI deficits without any changes in locomotor activity. Notably, DISC1 levels significantly decreased by NR2B knockdown. However, the effective dose of GLYX-13 did not alleviate the memory and PPI dysfunctions or downregulation of DISC1 induced by NR2B knockdown. Conclusion: Our results suggest GLYX-13 as a candidate for schizophrenia treatment, and NR2B and DISC1 in the hippocampus may account for the molecular mechanisms of GLYX-13.
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Affiliation(s)
- Dongsheng Zhou
- Ningbo Kangning Hospital, Ningbo, China.,Ningbo Key Laboratory of Behavioral Neuroscience, School of Medicine, Ningbo University, Ningbo, China
| | - Dan Lv
- Ningbo Key Laboratory of Behavioral Neuroscience, School of Medicine, Ningbo University, Ningbo, China.,Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, China.,Department of Physiology and Pharmacology, School of Medicine, Ningbo University, Ningbo, China
| | - Zhen Wang
- Key Laboratory for Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yanhua Zhang
- Ningbo Key Laboratory of Behavioral Neuroscience, School of Medicine, Ningbo University, Ningbo, China.,Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, China.,Department of Physiology and Pharmacology, School of Medicine, Ningbo University, Ningbo, China
| | | | - Chuang Wang
- Ningbo Key Laboratory of Behavioral Neuroscience, School of Medicine, Ningbo University, Ningbo, China.,Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, China.,Department of Physiology and Pharmacology, School of Medicine, Ningbo University, Ningbo, China
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31
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Sampedro-Piquero P, Begega A. Environmental Enrichment as a Positive Behavioral Intervention Across the Lifespan. Curr Neuropharmacol 2018; 15:459-470. [PMID: 27012955 PMCID: PMC5543669 DOI: 10.2174/1570159x14666160325115909] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/30/2015] [Accepted: 03/16/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND In recent decades, the interest in behavioral interventions has been growing due to the higher prevalence of age-related cognitive impairments. Hence, behavioral interventions, such as cognitive stimulation and physical activity, and along with these, our lifestyle (education level, work position, frequency of cognitive and social activities) have shown important benefits during the cognitive impairment, dementia and even recovery after brain injury. This is due to the fact that this type of intervention and activities promote the formation of a cognitive and brain reserve that allows tolerating brain damage during a long period of time without the appearance of cognitive symptoms. With regard to this, animal models have proved very useful in providing information about the brain mechanisms involved in the development of these cognitive and brain reserves and how they interact with each other. METHODS We summarize several studies showing the positive effects of Environmental Enrichment (EE), understood as a housing condition in which animals benefit from the sensory, physical, cognitive and social stimulation provided, on brain and cognitive functions usually impaired during aging. RESULTS Most of studies have shown that EE is a successful protocol to improve cognitive functions and reduce anxiety-related behaviors across the lifespan, as well as in animal models of neurodegenerative diseases. CONCLUSION Therefore, EE is a laboratory condition in which some aspects of an active lifestyle are reproduced.
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Affiliation(s)
- P Sampedro-Piquero
- Department of Biological and Health Psychology, Autonomous University of Madrid, Cantoblanco 28049, Madrid, Spain
| | - A Begega
- Neuroscience Laboratory, Psychology Department, University of Oviedo, Plaza Feijoo s/n 33003 Oviedo, INEUROPA, Spain
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Cortese GP, Olin A, O'Riordan K, Hullinger R, Burger C. Environmental enrichment improves hippocampal function in aged rats by enhancing learning and memory, LTP, and mGluR5-Homer1c activity. Neurobiol Aging 2017; 63:1-11. [PMID: 29207276 DOI: 10.1016/j.neurobiolaging.2017.11.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 01/20/2023]
Abstract
Previous studies from our laboratory have shown that environmental enrichment (EE) in young rats results in improved learning ability and enhanced metabotropic glutamate receptor-dependent long-term potentiation (mGluR-dependent LTP) resulting from sustained activation of p70S6 kinase. Here, we investigated whether 1-month EE is sufficient to improve hippocampus-dependent learning and memory and enhance hippocampal LTP in 23-24 month-old Fischer 344 male rats. Aged rats were housed in environmentally enriched, socially enriched, or standard housing conditions. We find that aged rats exposed to 1-month of EE demonstrate enhanced learning and memory relative to standard housed controls when tested in the Morris water maze and novel object recognition behavioral tasks. Furthermore, we find that environmentally enriched rats perform significantly better than socially enriched or standard housed rats in the radial-arm water maze and display enhanced mGluR5-dependent hippocampal LTP. Enhanced hippocampal function results from activity-dependent increases in the levels of mGluR5, Homer1c, and phospho-p70S6 kinase. These findings demonstrate that a short exposure of EE to aged rats can have significant effects on hippocampal function.
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Affiliation(s)
- Giuseppe P Cortese
- Department of Neurology, Medical Sciences Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Andrew Olin
- College of Letters and Science, University of Wisconsin-Madison, Madison, WI, USA
| | - Kenneth O'Riordan
- Department of Pharmacology & Therapeutics, Trinity College, Dublin, Ireland
| | - Rikki Hullinger
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Corinna Burger
- Department of Neurology, Medical Sciences Center, University of Wisconsin-Madison, Madison, WI, USA; Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA.
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Environmental enrichment attenuates behavioral abnormalities in valproic acid-exposed autism model mice. Behav Brain Res 2017; 333:67-73. [DOI: 10.1016/j.bbr.2017.06.035] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/14/2017] [Accepted: 06/20/2017] [Indexed: 01/16/2023]
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Environmental Factors Promoting Neural Plasticity: Insights from Animal and Human Studies. Neural Plast 2017; 2017:7219461. [PMID: 28740740 PMCID: PMC5504954 DOI: 10.1155/2017/7219461] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/17/2017] [Accepted: 05/10/2017] [Indexed: 11/17/2022] Open
Abstract
We do not all grow older in the same way. Some individuals have a cognitive decline earlier and faster than others who are older in years but cerebrally younger. This is particularly easy to verify in people who have maintained regular physical activity and healthy and cognitively stimulating lifestyle and even in the clinical field. There are patients with advanced neurodegeneration, such as Alzheimer's disease (AD), that, despite this, have mild cognitive impairment. What determines this interindividual difference? Certainly, it cannot be the result of only genetic factors. We are made in a certain manner and what we do acts on our brain. In fact, our genetic basis can be modulated, modified, and changed by our experiences such as education and life events; daily, by sleep schedules and habits; or also by dietary elements. And this can be seen as true even if our experiences are indirectly driven by our genetic basis. In this paper, we will review some current scientific research on how our experiences are able to modulate the structural organization of the brain and how a healthy lifestyle (regular physical activity, correct sleep hygiene, and healthy diet) appears to positively affect cognitive reserve.
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Joshi N, Leslie RA, Perrot TS. Analyzing the experiences of adolescent control rats: Effects of the absence of physical or social stimulation on anxiety-like behaviour are dependent on the test. Physiol Behav 2017; 179:30-41. [PMID: 28527682 DOI: 10.1016/j.physbeh.2017.05.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 01/01/2023]
Abstract
The present study was designed to systematically assess the control experience routinely used in our laboratory as part of studies on predator odour stress. Specifically, we examined effects of the physical and social components of this control experience on measures of anxiety-like behaviour in adolescent rats. Adolescent animals are at increased susceptibility to environmental perturbations and have been used for such studies much less often. Long-Evans rats of both sexes were subjected to physical stimulation (Exposed or Unexposed) and social stimulation (Single-Housed or Pair-Housed), resulting in four groups. Exposed rats received six 30-min exposures to an enclosed arena containing an unscented piece of cat collar occurring between adolescence and early adulthood, while Unexposed remained in the home cage. Groups of Exposed and Unexposed animals were housed singly (Single-Housed) from early adolescence to early adulthood or Pair-Housed during this time. Experimental procedures began in adolescence and involved repeated assessment of startle amplitude (measure of anxiety-like behaviour) and prepulse inhibition (PPI; a measure of sensorimotor gating) to gauge the short-term impact of social and/or physical stimulation. All animals were re-paired in adulthood prior to a final startle/PPI session to assess if isolation limited to adolescence could impose long-term effects that were not reversible. We also measured anxiety-like behaviour in adulthood using an extended open field test (EOFT; addition of novel objects to the open field on later days), and the elevated plus maze task (EPM), as well as a sucrose preference test (SPT) to measure anhedonia. An absence of social or physical stimulation resulted in increased startle amplitude and some measures of anxiety-like behaviour in the EOFT, but a reduction in such anxiety-like behaviour in the EPM task. These results suggest common neural substrates for the physical and social experiences. Performance in the SPT was unaltered by any experimental treatments. Sensorimotor gating, as measured by PPI, was increased in the absence of physical stimulation with no short-term effect of isolation, or of re-pairing. These results indicate the importance of considering individual components of the rearing environment of rats, while showing the need to use multiple assays of anxiety-like behaviour.
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Affiliation(s)
- Namrata Joshi
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - Ronald A Leslie
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Tara S Perrot
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Psychology & Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Brain Repair Centre, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
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Bhagya VR, Srikumar BN, Veena J, Shankaranarayana Rao BS. Short-term exposure to enriched environment rescues chronic stress-induced impaired hippocampal synaptic plasticity, anxiety, and memory deficits. J Neurosci Res 2016; 95:1602-1610. [DOI: 10.1002/jnr.23992] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 10/27/2016] [Accepted: 10/28/2016] [Indexed: 01/04/2023]
Affiliation(s)
- Venkanna Rao Bhagya
- Department of Neurophysiology; National Institute of Mental Health and Neuro Sciences (NIMHANS); Bengaluru India
| | - Bettadapura N. Srikumar
- Department of Neurophysiology; National Institute of Mental Health and Neuro Sciences (NIMHANS); Bengaluru India
| | - Jayagopalan Veena
- Department of Neurophysiology; National Institute of Mental Health and Neuro Sciences (NIMHANS); Bengaluru India
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Santos CM, Peres FF, Diana MC, Justi V, Suiama MA, Santana MG, Abílio VC. Peripubertal exposure to environmental enrichment prevents schizophrenia-like behaviors in the SHR strain animal model. Schizophr Res 2016; 176:552-559. [PMID: 27338757 DOI: 10.1016/j.schres.2016.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/04/2016] [Accepted: 06/07/2016] [Indexed: 11/28/2022]
Abstract
Schizophrenia is a highly disabling mental disorder, in which genetics and environmental factors interact culminating in the disease. The treatment of negative symptoms and cognitive deficits with antipsychotics is currently inefficient and is an important field of research. Environmental enrichment (EE) has been suggested to improve some cognitive deficits in animal models of various psychiatric disorders. In this study, we aimed to evaluate a possible beneficial effect of early and long-term exposure to EE on an animal model of schizophrenia, the SHR strain. Young male Wistar rats (control strain) and SHRs (21 post-natal days) were housed for 6weeks in two different conditions: in large cages (10 animals per cage) containing objects of different textures, forms, colors and materials that were changed 3 times/week (EE condition) or in standard cages (5 animals per cage - Control condition). Behavioral evaluations - social interaction (SI), locomotion, prepulse inhibition of startle (PPI) and spontaneous alternation (SA) - were performed 6weeks after the end of EE. SHRs presented deficits in PPI (a sensorimotor impairment), SI (mimicking the negative symptoms) and SA (a working memory deficit), and also hyperlocomotion (modeling the positive symptoms). EE was able to reduce locomotion and increase PPI in both strains, and to prevent the working memory deficit in SHRs. EE also increased the number of neurons in the CA1 and CA3 of the hippocampus. In conclusion, EE can be a potential nonpharmacological strategy to prevent some behavioral deficits associated with schizophrenia.
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Affiliation(s)
- Camila Mauricio Santos
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 3° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil
| | - Fernanda Fiel Peres
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 3° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil; Department of Pharmacology, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 5° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil
| | - Mariana Cepollaro Diana
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 3° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil
| | - Veronica Justi
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 3° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil
| | - Mayra Akimi Suiama
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 3° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil; Department of Pharmacology, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 5° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil
| | - Marcela Gonçalves Santana
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 3° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil; Department of Pharmacology, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 5° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil
| | - Vanessa Costhek Abílio
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences, Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 3° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil; Department of Pharmacology, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 5° andar, Ed. de Pesquisas II, CEP 04039-032 São Paulo, SP, Brazil
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Buschler A, Manahan-Vaughan D. Metabotropic glutamate receptor, mGlu5, mediates enhancements of hippocampal long-term potentiation after environmental enrichment in young and old mice. Neuropharmacology 2016; 115:42-50. [PMID: 27267685 DOI: 10.1016/j.neuropharm.2016.06.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 12/24/2022]
Abstract
The metabotropic glutamate (mGlu) receptor, mGlu5, is of particular relevance for hippocampal function. It is critically required for the expression of long-term potentiation (LTP) and long-term depression (LTD), regulates neuronal oscillations, maintains the stability of place fields and is required for hippocampus-dependent memory. MGlu5-dysfunctions are associated with profound cognitive deficits in humans, and mGlu5 has been targeted as a putative cognitive enhancer. Cognitive enhancement, by means of environmental enrichment (EE) in rodents, results in improved hippocampal synaptic plasticity and memory. Here, we explored whether mGlu5 contributes to these enhancements. MGlu5-antagonism dose-dependently impaired the early phase of LTP (>4 h) in the CA1 region of young(3-4 month old) mice. Late-LTP (>24 h) was also impaired. LTP (>24 h) elicited in old (10-14 month old) mice displayed reduced sensitivity to mGlu5 antagonism. Short-term potentiation (STP, < 2 h) that was elicited by weaker afferent stimulation was unaffected by mGlu5-antagonism in both age-groups. EE significantly amplified STP (<2 h) in old and young animals, but did not increase the duration of synaptic potentiation, or promote induction of LTP. The improvement in STP was prevented by mGlu5-antagonism, in both young and old animals. These results indicate that modifications of the synapse that underlie improvements of LTP by EE require the contribution of mGlu5. Strikingly, although LTP in old mice does not critically depend on mGlu5, improvements in synaptic potentiation resulting from EE are mGlu5-dependent in old mice. Regarded in light of the known role for mGlu5 in hippocampal function and pathophysiology, these data suggest that mGlu5 regulation of synaptic information storage is pivotal to optimal hippocampal function. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Arne Buschler
- Ruhr University Bochum, Medical Faculty, Department of Neurophysiology, Bochum, Germany
| | - Denise Manahan-Vaughan
- Ruhr University Bochum, Medical Faculty, Department of Neurophysiology, Bochum, Germany.
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Rahati M, Nozari M, Eslami H, Shabani M, Basiri M. Effects of enriched environment on alterations in the prefrontal cortex GFAP- and S100B-immunopositive astrocytes and behavioral deficits in MK-801-treated rats. Neuroscience 2016; 326:105-116. [PMID: 27063100 DOI: 10.1016/j.neuroscience.2016.03.065] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 03/17/2016] [Accepted: 03/29/2016] [Indexed: 10/22/2022]
Abstract
A plethora of studies have indicated that enriched environment (EE) paradigm provokes plastic and morphological changes in astrocytes with accompanying increments of their density and positively affects the behavior of rodents. We also previously documented that EE could be employed to preclude several behavioral abnormalities, mainly cognitive deficits, attributed to postnatal N-methyl-d-aspartate (NMDA) receptor antagonist (MK-801) treatment, as a rodent model of schizophrenia (SCH) aspects. Given this, the current study quantitatively investigated the number of cells, presumed to be astrocytes, expressing two astroglia-associated proteins (S100B and glial fibrillary acidic protein (GFAP)) by immunohistochemistry in the prefrontal cortex (PFC), along with anxiety and passive avoidance (PA) learning behaviors by utilizing elevated plus maze (EPM) and shuttle-box tests, in MK-801-treated male wistar rats submitted to EE and non-EE rats. Following a treatment regime of sub-chronic MK-801 (1.0mg/kg i.p. daily for five consecutive days from postnatal day (P) 6), S-100B-positive cells and anxiety level were markedly increased, while the GFAP-positive cells and PA learning were notably attenuated. The trend of diminished GFAP-immunopositive cells and elevated S100B-immunostained cells in the PFC was reversed in the SCH-like rats by exposure of animals to EE, commencing from birth up to the time of experiments on P28-85. Additionally, EE exhibited an ameliorating effect on the behavioral abnormalities evoked by MK-801. Overall, present findings support that improper astrocyte functioning and behavioral changes, reminiscent of the many facets of SCH, occur consequential to repetitive administration of MK-801 and that raising rat pups in an EE mitigates these alterations.
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Affiliation(s)
- M Rahati
- Department of Anatomical Sciences, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran; Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - M Nozari
- Department of Physiology, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - H Eslami
- Department of Pharmacology, Molecular Medicine Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - M Shabani
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - M Basiri
- Department of Anatomical Sciences, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran; Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
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Burrows EL, Hannan AJ. Cognitive endophenotypes, gene-environment interactions and experience-dependent plasticity in animal models of schizophrenia. Biol Psychol 2015; 116:82-9. [PMID: 26687973 DOI: 10.1016/j.biopsycho.2015.11.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 11/26/2015] [Accepted: 11/30/2015] [Indexed: 12/22/2022]
Abstract
Schizophrenia is a devastating brain disorder caused by a complex and heterogeneous combination of genetic and environmental factors. In order to develop effective new strategies to prevent and treat schizophrenia, valid animal models are required which accurately model the disorder, and ideally provide construct, face and predictive validity. The cognitive deficits in schizophrenia represent some of the most debilitating symptoms and are also currently the most poorly treated. Therefore it is crucial that animal models are able to capture the cognitive dysfunction that characterizes schizophrenia, as well as the negative and psychotic symptoms. The genomes of mice have, prior to the recent gene-editing revolution, proven the most easily manipulable of mammalian laboratory species, and hence most genetic targeting has been performed using mouse models. Importantly, when key environmental factors of relevance to schizophrenia are experimentally manipulated, dramatic changes in the phenotypes of these animal models are often observed. We will review recent studies in rodent models which provide insight into gene-environment interactions in schizophrenia. We will focus specifically on environmental factors which modulate levels of experience-dependent plasticity, including environmental enrichment, cognitive stimulation, physical activity and stress. The insights provided by this research will not only help refine the establishment of optimally valid animal models which facilitate development of novel therapeutics, but will also provide insight into the pathogenesis of schizophrenia, thus identifying molecular and cellular targets for future preclinical and clinical investigations.
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Affiliation(s)
- Emma L Burrows
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC 3010, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC 3010, Australia; Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC 3010, Australia.
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Ayhan Y, McFarland R, Pletnikov MV. Animal models of gene-environment interaction in schizophrenia: A dimensional perspective. Prog Neurobiol 2015; 136:1-27. [PMID: 26510407 DOI: 10.1016/j.pneurobio.2015.10.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 09/07/2015] [Accepted: 10/22/2015] [Indexed: 12/12/2022]
Abstract
Schizophrenia has long been considered as a disorder with multifactorial origins. Recent discoveries have advanced our understanding of the genetic architecture of the disease. However, even with the increase of identified risk variants, heritability estimates suggest an important contribution of non-genetic factors. Various environmental risk factors have been proposed to play a role in the etiopathogenesis of schizophrenia. These include season of birth, maternal infections, obstetric complications, adverse events at early childhood, and drug abuse. Despite the progress in identification of genetic and environmental risk factors, we still have a limited understanding of the mechanisms whereby gene-environment interactions (G × E) operate in schizophrenia and psychoses at large. In this review we provide a critical analysis of current animal models of G × E relevant to psychotic disorders and propose that dimensional perspective will advance our understanding of the complex mechanisms of these disorders.
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Affiliation(s)
- Yavuz Ayhan
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA; Hacettepe University Faculty of Medicine, Department of Psychiatry, Turkey
| | - Ross McFarland
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, USA
| | - Mikhail V Pletnikov
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA; Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, USA; Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, USA; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, USA.
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Bayat M, Sharifi MD, Haghani M, Shabani M. Enriched environment improves synaptic plasticity and cognitive deficiency in chronic cerebral hypoperfused rats. Brain Res Bull 2015; 119:34-40. [PMID: 26474515 DOI: 10.1016/j.brainresbull.2015.10.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 12/12/2022]
Abstract
Recent studies have indicated that environmental enrichment (EE) increases the sensorial and social stimulations and leads to strengthened plastic changes in the brain. In models of chronic cerebral hypoperfusion, the ability of an EE to restore the cognition depends on hippocampal synaptic plasticity. The mechanisms for this effect have not, however, been adequately studied. Thus, the aim of the present study was to evaluate the neuroprotective effects and underlying mechanism of environmental enrichment by assessment of spatial memory tasks as well as parameters of synaptic plasticity in rats subjected to occlusion of the bilateral common carotid arteries (2-VO) model. Male Sprague-Dawley rats were used in this study. The model group was established by occlusion of the bilateral common carotid arteries. The animals were tested for learning, memory performance and synaptic plasticity using Morris water maze (MWM), 8-arm Radial Maze (RM), and field potential recording, respectively. The rats subjected to 2-VO in EE exhibited a significantly lower number of working errors and reference errors in RM. Moreover, the enriched environment recovered the memory performance of hypoperfused rats and decreased the swimming time to reach the platform in MWM. In addition, conditions of the environment did not have any effect on baseline synaptic transmission and presynaptic plasticity, but housing the animals in EE rescued the impairment of LTP induction induced by 2-VO. These results suggest that EE ameliorates the LTP and spatial memory impairment induced by 2-VO. Our data indicated that the LTP recovery by EE in the rat models of 2-VO is probably mediated by post-synaptic mechanisms.
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Affiliation(s)
- Mahnaz Bayat
- Department of Physiology, International Branch, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Mohammad Davood Sharifi
- Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Masoud Haghani
- Histomorphometry and Stereology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Physiology, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Mohammad Shabani
- Kerman Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
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Decreased expression of mGluR5 within the dorsolateral prefrontal cortex in autism and increased microglial number in mGluR5 knockout mice: Pathophysiological and neurobehavioral implications. Brain Behav Immun 2015; 49:197-205. [PMID: 26052099 DOI: 10.1016/j.bbi.2015.05.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 05/16/2015] [Accepted: 05/28/2015] [Indexed: 12/29/2022] Open
Abstract
Metabotropic glutamate receptor 5 (mGluR5) and microglial abnormalities have been implicated in autism spectrum disorder (ASD). However, controversy exists as to whether the receptor is down or upregulated in functioning in ASD. In addition, whilst activation of mGluR5 has been shown to attenuate microglial activation, its role in maintaining microglial homeostasis during development has not been investigated. We utilised published microarray data from the dorsolateral prefrontal cortex (DLPFC) of control (n=30) and ASD (n=27) individuals to carry out regression analysis to assess gene expression of mGluR5 downstream signalling elements. We then conducted a post-mortem brain stereological investigation of the DLPFC, to estimate the proportion of mGluR5-positive neurons and glia. Finally, we carried out stereological investigation into numbers of microglia in mGluR5 knockout mice, relative to wildtype littermates, together with assessment of changes in microglial somal size, as an indicator of activation status. We found that gene expression of mGluR5 was significantly decreased in ASD versus controls (p=0.018) as well as downstream elements SHANK3 (p=0.005) and PLCB1 (p=0.009) but that the pro-inflammatory marker NOS2 was increased (p=0.047). Intensity of staining of mGluR5-positive neurons was also significantly decreased in ASD versus controls (p=0.016). Microglial density was significantly increased in mGluR5 knockout animals versus wildtype controls (p=0.011). Our findings provide evidence for decreased expression of mGluR5 and its signalling components representing a key pathophysiological hallmark in ASD with implications for the regulation of microglial number and activation during development. This is important in the context of microglia being considered to play key roles in synaptic pruning during development, with preservation of appropriate connectivity relevant for normal brain functioning.
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Shifting towards a model of mGluR5 dysregulation in schizophrenia: Consequences for future schizophrenia treatment. Neuropharmacology 2015; 115:73-91. [PMID: 26349010 DOI: 10.1016/j.neuropharm.2015.08.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 08/02/2015] [Accepted: 08/03/2015] [Indexed: 12/22/2022]
Abstract
Metabotropic glutamate receptor subtype 5 (mGluR5), encoded by the GRM5 gene, represents a compelling novel drug target for the treatment of schizophrenia. mGluR5 is a postsynaptic G-protein coupled glutamate receptor strongly linked with several critical cellular processes that are reported to be disrupted in schizophrenia. Accordingly, mGluR5 positive allosteric modulators show encouraging therapeutic potential in preclinical schizophrenia models, particularly for the treatment of cognitive dysfunctions against which currently available therapeutics are largely ineffective. More work is required to support the progression of mGluR5-targeting drugs into the clinic for schizophrenia treatment, although some obstacles may be overcome by comprehensively understanding how mGluR5 itself is involved in the neurobiology of the disorder. Several processes that are necessary for the regulation of mGluR5 activity have been identified, but not examined, in the context of schizophrenia. These processes include protein-protein interactions, dimerisation, subcellular trafficking, the impact of genetic variability or mutations on protein function, as well as epigenetic, post-transcriptional and post-translational processes. It is essential to understand these aspects of mGluR5 to determine whether they are affected in schizophrenia pathology, and to assess the consequences of mGluR5 dysfunction for the future use of mGluR5-based drugs. Here, we summarise the known processes that regulate mGluR5 and those that have already been studied in schizophrenia, and discuss the consequences of this dysregulation for current mGluR5 pharmacological strategies. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Environmental enrichment improves learning and memory and long-term potentiation in young adult rats through a mechanism requiring mGluR5 signaling and sustained activation of p70s6k. Neurobiol Learn Mem 2015; 125:126-34. [PMID: 26341144 DOI: 10.1016/j.nlm.2015.08.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 07/28/2015] [Accepted: 08/11/2015] [Indexed: 11/22/2022]
Abstract
Previous studies from our lab have demonstrated that mild cognitive impairments identified early in life are predictive of cognitive deficits that develop with age, suggesting that enhancements in cognition at an early age can provide a buffer against age-related cognitive decline. Environmental enrichment has been shown to improve learning and memory in the rodent, but the impact of enrichment on synaptic plasticity and the molecular mechanisms behind enrichment are not completely understood. To address these unresolved issues, we have housed 2-month old rats in environmentally enriched (EE), socially enriched (SE), or standard housing (SC) and conducted tests of learning and memory formation at various time intervals. Here we demonstrate that animals that have been exposed to one month of social or environmental enrichment demonstrate enhanced learning and memory relative to standard housed controls. However, we have found that after 4months EE animals perform better than both SE and SC groups and demonstrate an enhanced hippocampal LTP. Our results demonstrate that this LTP is dependent on mGluR5 signaling, activation of ERK and mTOR signaling cascades, and sustained phosphorylation of p70s6 kinase, thus providing a potential target mechanism for future studies of cognitive enhancement in the rodent.
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