1
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Tabaka O, Lawal S, Triana RDR, Hou M, Fraser A, Gallagher A, Ruiz KSA, Marmarcz M, Dickinson M, Oliveira MM, Klann E, Shrestha P. Aberrant TSC-Rheb axis in Oxytocin receptor+ cells mediate stress-induced anxiety. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600464. [PMID: 38979197 PMCID: PMC11230205 DOI: 10.1101/2024.06.25.600464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Stress is a major risk for the onset of several maladaptive processes including pathological anxiety, a diffuse state of heightened apprehension over anticipated threats 1 . Pathological anxiety is prevalent in up to 59% of patients with Tuberous Sclerosis complex (TSC) 2 , a neurodevelopmental disorder (NDD) caused by loss-of-function mutations in genes for Tuberin ( Tsc2 ) and/or Hamartin ( Tsc1 ) that together comprise the eponymous protein complex. Here, we generated cell type-specific heterozygous knockout of Tsc2 in cells expressing oxytocin receptor (OTRCs) to model pathological anxiety-like behaviors observed in TSC patient population. The stress of prolonged social isolation induces a sustained negative affective state that precipitates behavioral avoidance, often by aberrant oxytocin signaling in the limbic forebrain 3,4 . In response to social isolation, there were striking sex differences in stress susceptibility in conditional heterozygote mice when encountering situations of approach-avoidance conflict. Socially isolated male mutants exhibited behavioral avoidance in anxiogenic environments and sought more social interaction for buffering of stress. In contrast, female mutants developed resilience during social isolation and approached anxiogenic environments, while devaluing social interaction. Systemic and medial prefrontal cortex (mPFC)-specific inhibition of downstream effector of TSC, the integrated stress response (ISR), rescued behavioral approach toward anxiogenic environments and conspecifics in male and female mutant mice respectively. Further, we found that Tsc2 deletion in OTRCs leads to OTR-signaling elicited network suppression, i.e., hypofrontality, in male mPFC, which is relieved by inhibiting the ISR. Our findings present evidence in support of a sexually dimorphic role of prefrontal OTRCs in regulating emotional responses in anxiogenic environments, which goes awry in TSC. Our work has broader implications for developing effective treatments for subtypes of anxiety disorders that are characterized by cell-autonomous ISR and prefrontal network suppression.
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2
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Cording KR, Bateup HS. Altered motor learning and coordination in mouse models of autism spectrum disorder. Front Cell Neurosci 2023; 17:1270489. [PMID: 38026686 PMCID: PMC10663323 DOI: 10.3389/fncel.2023.1270489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/25/2023] [Indexed: 12/01/2023] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with increasing prevalence. Over 1,000 risk genes have now been implicated in ASD, suggesting diverse etiology. However, the diagnostic criteria for the disorder still comprise two major behavioral domains - deficits in social communication and interaction, and the presence of restricted and repetitive patterns of behavior (RRBs). The RRBs associated with ASD include both stereotyped repetitive movements and other motor manifestations including changes in gait, balance, coordination, and motor skill learning. In recent years, the striatum, the primary input center of the basal ganglia, has been implicated in these ASD-associated motor behaviors, due to the striatum's role in action selection, motor learning, and habit formation. Numerous mouse models with mutations in ASD risk genes have been developed and shown to have alterations in ASD-relevant behaviors. One commonly used assay, the accelerating rotarod, allows for assessment of both basic motor coordination and motor skill learning. In this corticostriatal-dependent task, mice walk on a rotating rod that gradually increases in speed. In the extended version of this task, mice engage striatal-dependent learning mechanisms to optimize their motor routine and stay on the rod for longer periods. This review summarizes the findings of studies examining rotarod performance across a range of ASD mouse models, and the resulting implications for the involvement of striatal circuits in ASD-related motor behaviors. While performance in this task is not uniform across mouse models, there is a cohort of models that show increased rotarod performance. A growing number of studies suggest that this increased propensity to learn a fixed motor routine may reflect a common enhancement of corticostriatal drive across a subset of mice with mutations in ASD-risk genes.
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Affiliation(s)
- Katherine R. Cording
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | - Helen S. Bateup
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Molecular and Cell Biology Department, University of California, Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
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3
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Longo F, Aryal S, Anastasiades PG, Maltese M, Baimel C, Albanese F, Tabor J, Zhu JD, Oliveira MM, Gastaldo D, Bagni C, Santini E, Tritsch NX, Carter AG, Klann E. Cell-type-specific disruption of cortico-striatal circuitry drives repetitive patterns of behavior in fragile X syndrome model mice. Cell Rep 2023; 42:112901. [PMID: 37505982 PMCID: PMC10552611 DOI: 10.1016/j.celrep.2023.112901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 05/18/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Individuals with fragile X syndrome (FXS) are frequently diagnosed with autism spectrum disorder (ASD), including increased risk for restricted and repetitive behaviors (RRBs). Consistent with observations in humans, FXS model mice display distinct RRBs and hyperactivity that are consistent with dysfunctional cortico-striatal circuits, an area relatively unexplored in FXS. Using a multidisciplinary approach, we dissect the contribution of two populations of striatal medium spiny neurons (SPNs) in the expression of RRBs in FXS model mice. Here, we report that dysregulated protein synthesis at cortico-striatal synapses is a molecular culprit of the synaptic and ASD-associated motor phenotypes displayed by FXS model mice. Cell-type-specific translational profiling of the FXS mouse striatum reveals differentially translated mRNAs, providing critical information concerning potential therapeutic targets. Our findings uncover a cell-type-specific impact of the loss of fragile X messenger ribonucleoprotein (FMRP) on translation and the sequence of neuronal events in the striatum that drive RRBs in FXS.
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Affiliation(s)
- Francesco Longo
- Center for Neural Science, New York University, New York, NY 10003, USA; Institute for Neuroscience and Physiology, University of Gothenburg, 40530 Gothenburg, Sweden; Sackler Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY 10016, USA
| | - Sameer Aryal
- Center for Neural Science, New York University, New York, NY 10003, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
| | | | - Marta Maltese
- Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY 10016, USA; Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
| | - Corey Baimel
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Federica Albanese
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Joanna Tabor
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Jeffrey D Zhu
- Center for Neural Science, New York University, New York, NY 10003, USA
| | | | - Denise Gastaldo
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 1005 Rome, Italy
| | - Claudia Bagni
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 1005 Rome, Italy
| | - Emanuela Santini
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience, Biomedicum, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Nicolas X Tritsch
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA; Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY 10016, USA
| | - Adam G Carter
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY 10003, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA.
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4
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Frare C, Pitt SK, Hewett SJ. Sex- and age-dependent contribution of System x c- to cognitive, sensory, and social behaviors revealed by comprehensive behavioral analyses of System x c- null mice. Front Behav Neurosci 2023; 17:1238349. [PMID: 37649973 PMCID: PMC10462982 DOI: 10.3389/fnbeh.2023.1238349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 07/31/2023] [Indexed: 09/01/2023] Open
Abstract
Background System xc- (Sxc-) is an important heteromeric amino acid cystine/glutamate exchanger that plays a pivotal role in the CNS by importing cystine into cells while exporting glutamate. Although certain behaviors have been identified as altered in Sxc- null mutant mice, our understanding of the comprehensive impact of Sxc- on behavior remains incomplete. Methods To address this gap, we compared motor, sensory and social behaviors of male and female mice in mice null for Sxc- (SLC7A11sut/sut) with wildtype littermates (SLC7A11+/+) in a comprehensive and systematic manner to determine effects of genotype, sex, age, and their potential interactions. Results Motor performance was not affected by loss of Sxc- in both males and females, although it was impacted negatively by age. Motor learning was specifically disrupted in female mice lacking Sxc- at both 2 and 6 months of age. Further, female SLC7A11sut/sut mice at both ages exhibited impaired sociability, but normal spatial and recognition memory, as well as sensorimotor gating. Finally, pronounced open-space anxiety was displayed by female SLC7A11sut/sut when they were young. In contrast, young SLC7A11sut/sut male mice demonstrated normal sociability, delayed spatial learning, increased open-space anxiety and heightened sensitivity to noise. As they aged, anxiety and noise sensitivity abated but hyperactivity emerged. Discussion We find that the behavioral phenotypes of female SLC7A11sut/sut are similar to those observed in mouse models of autism spectrum disorder, while behaviors of male SLC7A11sut/sut resemble those seen in mouse models of attention deficit hyperactivity disorder. These results underscore the need for further investigation of SLC7A11 in neurodevelopment. By expanding our understanding of the potential involvement of Sxc-, we may gain additional insights into the mechanisms underlying complex neurodevelopmental conditions.
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Affiliation(s)
| | | | - Sandra J. Hewett
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, NY, United States
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5
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Shimada T, Yamagata K. Spine morphogenesis and synapse formation in tubular sclerosis complex models. Front Mol Neurosci 2022; 15:1019343. [PMID: 36606143 PMCID: PMC9807618 DOI: 10.3389/fnmol.2022.1019343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is caused by mutations in the Tsc1 or Tsc2 genes, whose products form a complex and inactivate the small G-protein Rheb1. The activation of Rheb1 may cause refractory epilepsy, intellectual disability, and autism, which are the major neuropsychiatric manifestations of TSC. Abnormalities in dendritic spines and altered synaptic structure are hallmarks of epilepsy, intellectual disability, and autism. In addition, spine dysmorphology and aberrant synapse formation are observed in TSC animal models. Therefore, it is important to investigate the molecular mechanism underlying the regulation of spine morphology and synapse formation in neurons to identify therapeutic targets for TSC. In this review, we focus on the representative proteins regulated by Rheb1 activity, mTORC1 and syntenin, which are pivotal downstream factors of Rheb1 in the alteration of spine formation and synapse function in TSC neurons.
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Affiliation(s)
- Tadayuki Shimada
- Child Brain Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan,*Correspondence: Tadayuki Shimada,
| | - Kanato Yamagata
- Child Brain Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan,Department of Psychiatry, Takada Nishishiro Hospital, Niigata, Japan,Kanato Yamagata,
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6
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Petrasek T, Vojtechova I, Klovrza O, Tuckova K, Vejmola C, Rak J, Sulakova A, Kaping D, Bernhardt N, de Vries PJ, Otahal J, Waltereit R. mTOR inhibitor improves autistic-like behaviors related to Tsc2 haploinsufficiency but not following developmental status epilepticus. J Neurodev Disord 2021; 13:14. [PMID: 33863288 PMCID: PMC8052752 DOI: 10.1186/s11689-021-09357-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/18/2021] [Indexed: 12/18/2022] Open
Abstract
Background Tuberous sclerosis complex (TSC), a multi-system genetic disorder often associated with autism spectrum disorder (ASD), is caused by mutations of TSC1 or TSC2, which lead to constitutive overactivation of mammalian target of rapamycin (mTOR). In several Tsc1+/- and Tsc2+/- animal models, cognitive and social behavior deficits were reversed by mTOR inhibitors. However, phase II studies have not shown amelioration of ASD and cognitive deficits in individuals with TSC during mTOR inhibitor therapy. We asked here if developmental epilepsy, common in the majority of individuals with TSC but absent in most animal models, could explain the discrepancy. Methods At postnatal day P12, developmental status epilepticus (DSE) was induced in male Tsc2+/- (Eker) and wild-type rats, establishing four experimental groups including controls. In adult animals (n = 36), the behavior was assessed in the paradigms of social interaction test, elevated plus-maze, light-dark test, Y-maze, and novel object recognition. The testing was carried out before medication (T1), during a 2-week treatment with the mTOR inhibitor everolimus (T2) and after an 8-week washing-out (T3). Electroencephalographic (EEG) activity was recorded in a separate set of animals (n = 18). Results Both Tsc2+/- mutation and DSE caused social behavior deficits and epileptiform EEG abnormalities (T1). Everolimus led to a persistent improvement of the social deficit induced by Tsc2+/-, while deficits related to DSE did not respond to everolimus (T2, T3). Conclusions These findings may contribute to an explanation why ASD symptoms in individuals with TSC, where comorbid early-onset epilepsy is common, were not reliably ameliorated by mTOR inhibitors in clinical studies. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-021-09357-2.
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Affiliation(s)
- Tomas Petrasek
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic.
| | - Iveta Vojtechova
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic.,First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Ondrej Klovrza
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic.,Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Klara Tuckova
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Cestmir Vejmola
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic
| | - Jakub Rak
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic
| | - Anna Sulakova
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic
| | - Daniel Kaping
- National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic
| | - Nadine Bernhardt
- Department of Psychiatry, University Hospital and Medical Faculty Carl Gustav Carus, Technical University of Dresden, Dresden, Germany
| | - Petrus J de Vries
- Division of Child & Adolescent Psychiatry, University of Cape Town, Cape Town, South Africa
| | - Jakub Otahal
- Department of Developmental Epileptology, Institute of Physiology CAS, Prague, Czech Republic
| | - Robert Waltereit
- Department of Child and Adolescent Psychiatry, University Hospital and Medical Faculty Carl Gustav Carus, Technical University of Dresden, Dresden, Germany. .,Department of Child and Adolescent Psychiatry, University Medical Center Göttingen, Von-Siebold-Str. 5, 37075, Göttingen, Germany.
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7
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Carroll L, Braeutigam S, Dawes JM, Krsnik Z, Kostovic I, Coutinho E, Dewing JM, Horton CA, Gomez-Nicola D, Menassa DA. Autism Spectrum Disorders: Multiple Routes to, and Multiple Consequences of, Abnormal Synaptic Function and Connectivity. Neuroscientist 2020; 27:10-29. [PMID: 32441222 PMCID: PMC7804368 DOI: 10.1177/1073858420921378] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Autism spectrum disorders (ASDs) are a heterogeneous group of
neurodevelopmental disorders of genetic and environmental etiologies.
Some ASD cases are syndromic: associated with clinically defined
patterns of somatic abnormalities and a neurobehavioral phenotype
(e.g., Fragile X syndrome). Many cases, however, are idiopathic or
non-syndromic. Such disorders present themselves during the early
postnatal period when language, speech, and personality start to
develop. ASDs manifest by deficits in social communication and
interaction, restricted and repetitive patterns of behavior across
multiple contexts, sensory abnormalities across multiple modalities
and comorbidities, such as epilepsy among many others. ASDs are
disorders of connectivity, as synaptic dysfunction is common to both
syndromic and idiopathic forms. While multiple theories have been
proposed, particularly in idiopathic ASDs, none address why certain
brain areas (e.g., frontotemporal) appear more vulnerable than others
or identify factors that may affect phenotypic specificity. In this
hypothesis article, we identify possible routes leading to, and the
consequences of, altered connectivity and review the evidence of
central and peripheral synaptic dysfunction in ASDs. We postulate that
phenotypic specificity could arise from aberrant experience-dependent
plasticity mechanisms in frontal brain areas and peripheral sensory
networks and propose why the vulnerability of these areas could be
part of a model to unify preexisting pathophysiological theories.
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Affiliation(s)
- Liam Carroll
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, Oxfordshire, UK
| | - Sven Braeutigam
- Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, Oxfordshire, UK
| | - John M Dawes
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, Oxfordshire, UK
| | - Zeljka Krsnik
- Croatian Institute for Brain Research, Centre of Research Excellence for Basic, Clinical and Translational Neuroscience, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ivica Kostovic
- Croatian Institute for Brain Research, Centre of Research Excellence for Basic, Clinical and Translational Neuroscience, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ester Coutinho
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Jennifer M Dewing
- Faculty of Medicine, University of Southampton, Southampton, Hampshire, UK
| | - Christopher A Horton
- Sir William Dunn School of Pathology, University of Oxford, Oxford, Oxfordshire, UK
| | - Diego Gomez-Nicola
- Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - David A Menassa
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, Oxfordshire, UK.,Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
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8
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Sex-Selective Effects on Behavior in a Mouse Model of Tuberous Sclerosis Complex. eNeuro 2020; 7:ENEURO.0379-19.2020. [PMID: 32303566 PMCID: PMC7196723 DOI: 10.1523/eneuro.0379-19.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 01/19/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder that is caused by a mutation in either TSC1 or TSC2 TSC affects multiple systems of the body, and patients with TSC display a range of neurologic and behavioral manifestations including seizures, intellectual disability, autism spectrum disorders, attention deficit hyperactivity disorder, anxiety, and mood disorders. Whereas behavioral phenotypes of many mouse models have been studied, the effects of sex have, for the most part, not been explored. We studied adult male and female Tsc2 heterozygous and control mice to investigate the influence of sex and genotype on behavior. On a test of social preference, Tsc2 heterozygous mice, regardless of sex, demonstrated lower preference for the stranger mouse than control mice. In the open field, Tsc2 heterozygous males and control females habituated to the open field with decreasing anxiety-like behavior over time, whereas Tsc2 heterozygous females did not show habituation to the open field environment. We did not find any statistically significant effects of genotype on open field activity, learning and memory or motor function. Our results highlight phenotype differences in Tsc2 heterozygous mice, some of which are influenced by sex. A consideration of how sex influences the behavioral phenotypes of TSC is critical to develop a more complete understanding of the disorder and better target future pharmacological treatments.
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9
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Okamoto SI, Prikhodko O, Pina-Crespo J, Adame A, McKercher SR, Brill LM, Nakanishi N, Oh CK, Nakamura T, Masliah E, Lipton SA. NitroSynapsin for the treatment of neurological manifestations of tuberous sclerosis complex in a rodent model. Neurobiol Dis 2019; 127:390-397. [PMID: 30928642 DOI: 10.1016/j.nbd.2019.03.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/07/2019] [Accepted: 03/26/2019] [Indexed: 12/13/2022] Open
Abstract
Tuberous sclerosis (TSC) is an autosomal dominant disorder caused by heterozygous mutations in the TSC1 or TSC2 gene. TSC is often associated with neurological, cognitive, and behavioral deficits. TSC patients also express co-morbidity with anxiety and mood disorders. The mechanism of pathogenesis in TSC is not entirely clear, but TSC-related neurological symptoms are accompanied by excessive glutamatergic activity and altered synaptic spine structures. To address whether extrasynaptic (e)NMDA-type glutamate receptor (NMDAR) antagonists, as opposed to antagonists that block physiological phasic synaptic activity, can ameliorate the synaptic and behavioral features of this disease, we utilized the Tsc2+/- mouse model of TSC to measure biochemical, electrophysiological, histological, and behavioral parameters in the mice. We found that antagonists that preferentially block tonic activity as found at eNMDARs, particularly the newer drug NitroSynapsin, provide biological and statistically significant improvement in Tsc2+/- phenotypes. Accompanying this improvement was correction of activity in the p38 MAPK-TSC-Rheb-mTORC1-S6K1 pathway. Deficits in hippocampal long-term potentiation (LTP), histological loss of synapses, and behavioral fear conditioning in Tsc2+/- mice were all improved after treatment with NitroSynapsin. Taken together, these results suggest that amelioration of excessive excitation, by limiting aberrant eNMDAR activity, may represent a novel treatment approach for TSC.
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Affiliation(s)
| | - Olga Prikhodko
- Biomedical Sciences Graduate Program, University of California San Diego, School of Medicine, La Jolla, CA 92093, USA
| | - Juan Pina-Crespo
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Anthony Adame
- Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, CA 92093, USA
| | - Scott R McKercher
- Scintillon Institute, San Diego, CA 92121, USA; Neuroscience Translational Center, Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Laurence M Brill
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | | | - Chang-Ki Oh
- Scintillon Institute, San Diego, CA 92121, USA; Neuroscience Translational Center, Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tomohiro Nakamura
- Scintillon Institute, San Diego, CA 92121, USA; Neuroscience Translational Center, Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, CA 92093, USA
| | - Stuart A Lipton
- Scintillon Institute, San Diego, CA 92121, USA; Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, CA 92093, USA; Neuroscience Translational Center, Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA.
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10
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Borrie SC, Brems H, Legius E, Bagni C. Cognitive Dysfunctions in Intellectual Disabilities: The Contributions of the Ras-MAPK and PI3K-AKT-mTOR Pathways. Annu Rev Genomics Hum Genet 2017; 18:115-142. [DOI: 10.1146/annurev-genom-091416-035332] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sarah C. Borrie
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Hilde Brems
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Eric Legius
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Claudia Bagni
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
- Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00173 Rome, Italy
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11
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López-Cruz L, Carbó-Gas M, Pardo M, Bayarri P, Valverde O, Ledent C, Salamone JD, Correa M. Adenosine A 2A receptor deletion affects social behaviors and anxiety in mice: Involvement of anterior cingulate cortex and amygdala. Behav Brain Res 2017; 321:8-17. [DOI: 10.1016/j.bbr.2016.12.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/10/2016] [Accepted: 12/16/2016] [Indexed: 02/06/2023]
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12
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López-Cruz L, San-Miguel N, Bayarri P, Baqi Y, Müller CE, Salamone JD, Correa M. Ethanol and Caffeine Effects on Social Interaction and Recognition in Mice: Involvement of Adenosine A 2A and A 1 Receptors. Front Behav Neurosci 2016; 10:206. [PMID: 27853423 PMCID: PMC5090123 DOI: 10.3389/fnbeh.2016.00206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/10/2016] [Indexed: 11/28/2022] Open
Abstract
Ethanol and caffeine are frequently consumed in combination and have opposite effects on the adenosine system: ethanol metabolism leads to an increase in adenosine levels, while caffeine is a non-selective adenosine A1/A2A receptor antagonist. These receptors are highly expressed in striatum and olfactory tubercle, brain areas involved in exploration and social interaction in rodents. Ethanol modulates social interaction processes, but the role of adenosine in social behavior is still poorly understood. The present work was undertaken to study the impact of ethanol, caffeine and their combination on social behavior, and to explore the involvement of A1 and A2A receptors on those actions. Male CD1 mice were evaluated in a social interaction three-chamber paradigm, for preference of conspecific vs. object, and also for long-term recognition memory of familiar vs. novel conspecific. Ethanol showed a biphasic effect, with low doses (0.25 g/kg) increasing social contact and higher doses (1.0-1.5 g/kg) reducing social interaction. However, no dose changed social preference; mice always spent more time sniffing the conspecific than the object, independently of the ethanol dose. Ethanol, even at doses that did not change social exploration, produced amnestic effects on social recognition the following day. Caffeine reduced social contact (15.0-60.0 mg/kg), and even blocked social preference at higher doses (30.0-60.0 mg/kg). The A1 antagonist Cyclopentyltheophylline (CPT; 3-9 mg/kg) did not modify social contact or preference on its own, and the A2A antagonist MSX-3 (1.5-6 mg/kg) increased social interaction at all doses. Ethanol at intermediate doses (0.5-1.0 g/kg) was able to reverse the reduction in social exploration induced by caffeine (15.0-30.0 mg/kg). Although there was no interaction between ethanol and CPT or MSX-3 on social exploration in the first day, MSX-3 blocked the amnestic effects of ethanol observed on the following day. Thus, ethanol impairs the formation of social memories, and A2A adenosine antagonists can prevent the amnestic effects of ethanol, so that animals can recognize familiar conspecifics. On the other hand, ethanol can counteract the social withdrawal induced by caffeine, a non-selective adenosine A1/A2A receptor antagonist. These results show the complex set of interactions between ethanol and caffeine, some of which could be the result of the opposing effects they have in modulating the adenosine system.
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Affiliation(s)
- Laura López-Cruz
- Àrea de Psicobiologia, Campus de Riu Sec, Universitat Jaume ICastelló, Spain
| | - Noemí San-Miguel
- Àrea de Psicobiologia, Campus de Riu Sec, Universitat Jaume ICastelló, Spain
| | - Pilar Bayarri
- Àrea de Psicobiologia, Campus de Riu Sec, Universitat Jaume ICastelló, Spain
| | - Younis Baqi
- Pharma-Zentrum Bonn, Pharmazeutisches Institut, Pharmazeutische Chemie, Universität BonnBonn, Germany
| | - Christa E. Müller
- Pharma-Zentrum Bonn, Pharmazeutisches Institut, Pharmazeutische Chemie, Universität BonnBonn, Germany
| | - John D. Salamone
- Department of Psychological Sciences, University of ConnecticutStorrs, CT, USA
| | - Mercé Correa
- Àrea de Psicobiologia, Campus de Riu Sec, Universitat Jaume ICastelló, Spain
- Department of Psychological Sciences, University of ConnecticutStorrs, CT, USA
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13
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Tsc1 haploinsufficiency is sufficient to increase dendritic patterning and Filamin A levels. Neurosci Lett 2016; 629:15-18. [PMID: 27345385 DOI: 10.1016/j.neulet.2016.06.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/17/2016] [Accepted: 06/20/2016] [Indexed: 12/22/2022]
Abstract
Most individuals with tuberous sclerosis complex (TSC) are born with a mutant allele of either TSC1 or TSC2 and a mosaic of psychological and cognitive defects. Tsc1 loss of heterozygosity contributes to severe dendritic abnormalities that are rescued by normalizing the levels of the actin-cross linking protein, Filamin A (FLNA). However, it is unclear whether dendrites and FLNA levels are abnormal in an heterozygote Tsc1 condition. Here, we examined dendritic morphology and FLNA levels in the olfactory bulb of Tsc1 wild type and heterozygote mice. Using in vivo neonatal electroporation to label newborn neurons followed by sholl analysis, we found that Tsc1 haploinsufficiency is associated with increased dendritic complexity and total dendritic length as well as increased FLNA levels. Since reducing FLNA levels has been shown to decrease Tsc1(+/-) dendritic complexity, these data suggest that increased FLNA levels in Tsc1(+/-) mice contribute to abnormal dendritic patterning in the Tsc1 heterozygote condition of individuals with TSC.
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14
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Kim KC, Gonzales EL, Lázaro MT, Choi CS, Bahn GH, Yoo HJ, Shin CY. Clinical and Neurobiological Relevance of Current Animal Models of Autism Spectrum Disorders. Biomol Ther (Seoul) 2016; 24:207-43. [PMID: 27133257 PMCID: PMC4859786 DOI: 10.4062/biomolther.2016.061] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 04/05/2016] [Indexed: 12/24/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and communication impairments, as well as repetitive and restrictive behaviors. The phenotypic heterogeneity of ASD has made it overwhelmingly difficult to determine the exact etiology and pathophysiology underlying the core symptoms, which are often accompanied by comorbidities such as hyperactivity, seizures, and sensorimotor abnormalities. To our benefit, the advent of animal models has allowed us to assess and test diverse risk factors of ASD, both genetic and environmental, and measure their contribution to the manifestation of autistic symptoms. At a broader scale, rodent models have helped consolidate molecular pathways and unify the neurophysiological mechanisms underlying each one of the various etiologies. This approach will potentially enable the stratification of ASD into clinical, molecular, and neurophenotypic subgroups, further proving their translational utility. It is henceforth paramount to establish a common ground of mechanistic theories from complementing results in preclinical research. In this review, we cluster the ASD animal models into lesion and genetic models and further classify them based on the corresponding environmental, epigenetic and genetic factors. Finally, we summarize the symptoms and neuropathological highlights for each model and make critical comparisons that elucidate their clinical and neurobiological relevance.
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Affiliation(s)
- Ki Chan Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Center for Neuroscience Research, SMART Institute of Advanced Biomedical Sciences, Konkuk University, Seoul 05029, Republic of Korea
| | - Edson Luck Gonzales
- Center for Neuroscience Research, SMART Institute of Advanced Biomedical Sciences, Konkuk University, Seoul 05029, Republic of Korea.,School of Medicine, Konkuk University, Seoul 05029, Republic of Korea
| | - María T Lázaro
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Chang Soon Choi
- Center for Neuroscience Research, SMART Institute of Advanced Biomedical Sciences, Konkuk University, Seoul 05029, Republic of Korea.,School of Medicine, Konkuk University, Seoul 05029, Republic of Korea
| | - Geon Ho Bahn
- Department of Neuropsychiatry, School of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Hee Jeong Yoo
- Department of Neuropsychiatry, Seoul National University Bungdang Hospital, Seongnam 13620, Republic of Korea
| | - Chan Young Shin
- Center for Neuroscience Research, SMART Institute of Advanced Biomedical Sciences, Konkuk University, Seoul 05029, Republic of Korea.,School of Medicine, Konkuk University, Seoul 05029, Republic of Korea
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15
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Kazdoba TM, Leach PT, Crawley JN. Behavioral phenotypes of genetic mouse models of autism. GENES, BRAIN, AND BEHAVIOR 2016; 15:7-26. [PMID: 26403076 PMCID: PMC4775274 DOI: 10.1111/gbb.12256] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/27/2015] [Accepted: 09/18/2015] [Indexed: 12/11/2022]
Abstract
More than a hundred de novo single gene mutations and copy-number variants have been implicated in autism, each occurring in a small subset of cases. Mutant mouse models with syntenic mutations offer research tools to gain an understanding of the role of each gene in modulating biological and behavioral phenotypes relevant to autism. Knockout, knockin and transgenic mice incorporating risk gene mutations detected in autism spectrum disorder and comorbid neurodevelopmental disorders are now widely available. At present, autism spectrum disorder is diagnosed solely by behavioral criteria. We developed a constellation of mouse behavioral assays designed to maximize face validity to the types of social deficits and repetitive behaviors that are central to an autism diagnosis. Mouse behavioral assays for associated symptoms of autism, which include cognitive inflexibility, anxiety, hyperactivity, and unusual reactivity to sensory stimuli, are frequently included in the phenotypic analyses. Over the past 10 years, we and many other laboratories around the world have employed these and additional behavioral tests to phenotype a large number of mutant mouse models of autism. In this review, we highlight mouse models with mutations in genes that have been identified as risk genes for autism, which work through synaptic mechanisms and through the mTOR signaling pathway. Robust, replicated autism-relevant behavioral outcomes in a genetic mouse model lend credence to a causal role for specific gene contributions and downstream biological mechanisms in the etiology of autism.
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Affiliation(s)
- T. M. Kazdoba
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - P. T. Leach
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - J. N. Crawley
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
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16
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Tuber-Less Models of Tuberous Sclerosis Still Provide Insights Into Epilepsy. Epilepsy Curr 2015; 15:129-30. [PMID: 26316849 DOI: 10.5698/1535-7597-15.3.129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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17
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Kirschstein T, Köhling R. Animal models of tumour-associated epilepsy. J Neurosci Methods 2015; 260:109-17. [PMID: 26092434 DOI: 10.1016/j.jneumeth.2015.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 01/26/2023]
Abstract
Brain tumours cause a sizeable proportion of epilepsies in adulthood, and actually can be etiologically responsible also for childhood epilepsies. Conversely, seizures are often first clinical signs of a brain tumour. Nevertheless, several issues of brain-tumour associated seizures and epilepsies are far from understood, or clarified regarding clinical consensus. These include both the specific mechanisms of epileptogenesis related to different tumour types, the possible relationship between malignancy and seizure emergence, the interaction between tumour mass and surrounding neuronal networks, and - not least - the best treatment options depending on different tumour types. To investigate these issues, experimental models of tumour-induced epilepsies are necessary. This review concentrates on the description of currently used models, focusing on methodological aspects. It highlights advantages and shortcomings of these models, and identifies future experimental challenges.
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Affiliation(s)
- Timo Kirschstein
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany.
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18
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Phillips M, Pozzo-Miller L. Dendritic spine dysgenesis in autism related disorders. Neurosci Lett 2015; 601:30-40. [PMID: 25578949 DOI: 10.1016/j.neulet.2015.01.011] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/31/2014] [Accepted: 01/04/2015] [Indexed: 01/22/2023]
Abstract
The activity-dependent structural and functional plasticity of dendritic spines has led to the long-standing belief that these neuronal compartments are the subcellular sites of learning and memory. Of relevance to human health, central neurons in several neuropsychiatric illnesses, including autism related disorders, have atypical numbers and morphologies of dendritic spines. These so-called dendritic spine dysgeneses found in individuals with autism related disorders are consistently replicated in experimental mouse models. Dendritic spine dysgenesis reflects the underlying synaptopathology that drives clinically relevant behavioral deficits in experimental mouse models, providing a platform for testing new therapeutic approaches. By examining molecular signaling pathways, synaptic deficits, and spine dysgenesis in experimental mouse models of autism related disorders we find strong evidence for mTOR to be a critical point of convergence and promising therapeutic target.
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Affiliation(s)
- Mary Phillips
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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19
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Rozas NS, Redell JB, Hill JL, McKenna J, Moore AN, Gambello MJ, Dash PK. Genetic activation of mTORC1 signaling worsens neurocognitive outcome after traumatic brain injury. J Neurotrauma 2014; 32:149-58. [PMID: 25025304 DOI: 10.1089/neu.2014.3469] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Although the mechanisms that contribute to the development of traumatic brain injury (TBI)-related deficits are not fully understood, it has been proposed that altered energy utilization may be a contributing factor. The tuberous sclerosis complex, a heterodimer composed of hamartin/Tsc-1 and tuberin/Tsc-2, is a critical regulatory node that integrates nutritional and growth signals to govern energy using processes by regulating the activity of mechanistic Target of Rapamycin complex 1 (mTORC1). mTORC1 activation results in enhanced protein synthesis, an energy consuming process. We show that mice that have a heterozygous deletion of Tsc2 exhibit elevated basal mTORC1 activity in the cortex and the hippocampus while still exhibiting normal motor and neurocognitive functions. In addition, a mild closed head injury (mCHI) that did not activate mTORC1 in wild-type mice resulted in a further increase in mTORC1 activity in Tsc2(+/KO) mice above the level of activity observed in uninjured Tsc2(+/KO) mice. This enhanced level of increased mTORC1 activity was associated with worsened cognitive function as assessed using the Morris water maze and context discrimination tasks. These results suggest that there is a threshold of increased mTORC1 activity after a TBI that is detrimental to neurobehavioral performance, and interventions to inhibit excessive mTORC1 activation may be beneficial to neurocognitive outcome.
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Affiliation(s)
- Natalia S Rozas
- 1 Department of Neurobiology and Anatomy, the University of Texas Medical School , Houston, Texas
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20
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Bowling H, Klann E. Shaping dendritic spines in autism spectrum disorder: mTORC1-dependent macroautophagy. Neuron 2014; 83:994-6. [PMID: 25189205 DOI: 10.1016/j.neuron.2014.08.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In this issue of Neuron, Tang et al. (2014) explore the relationship between developmental dendritic pruning, elevated mTORC1 signaling, macroautophagy, and autism spectrum disorder. The study provides valuable new insight into mTORC1-dependent cellular dysfunction and neurodevelopmental disorders.
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Affiliation(s)
- Heather Bowling
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY 10003, USA.
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21
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McMahon JJ, Yu W, Yang J, Feng H, Helm M, McMahon E, Zhu X, Shin D, Huang Y. Seizure-dependent mTOR activation in 5-HT neurons promotes autism-like behaviors in mice. Neurobiol Dis 2014; 73:296-306. [PMID: 25315683 DOI: 10.1016/j.nbd.2014.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/23/2014] [Accepted: 10/01/2014] [Indexed: 11/15/2022] Open
Abstract
Epilepsy and autism spectrum disorder (ASD) are common comorbidities of one another. Despite the prevalent correlation between the two disorders, few studies have been able to elucidate a mechanistic link. We demonstrate that forebrain specific Tsc1 deletion in mice causes epilepsy and autism-like behaviors, concomitant with disruption of 5-HT neurotransmission. We find that epileptiform activity propagates to the raphe nuclei, resulting in seizure-dependent hyperactivation of mTOR in 5-HT neurons. To dissect whether mTOR hyperactivity in 5-HT neurons alone was sufficient to recapitulate an autism-like phenotype we utilized Tsc1flox/flox;Slc6a4-cre mice, in which mTOR is restrictively hyperactivated in 5-HT neurons. Tsc1flox/flox;Slc6a4-cre mice displayed alterations of the 5-HT system and autism-like behaviors, without causing epilepsy. Rapamycin treatment in these mice was sufficient to rescue the phenotype. We conclude that the spread of seizure activity to the brainstem is capable of promoting hyperactivation of mTOR in the raphe nuclei, which in turn promotes autism-like behaviors. Thus our study provides a novel mechanism describing how epilepsy can contribute to the development of autism-like behaviors, suggesting new therapeutic strategies for autism.
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Affiliation(s)
- John J McMahon
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Wilson Yu
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Jun Yang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, NY 12208, USA
| | - Haihua Feng
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Meghan Helm
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Elizabeth McMahon
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Xinjun Zhu
- Center for Cardiovascular Sciences, Albany Medical College, Albany, NY 12208, USA
| | - Damian Shin
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Yunfei Huang
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA.
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22
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Tang G, Gudsnuk K, Kuo SH, Cotrina ML, Rosoklija G, Sosunov A, Sonders MS, Kanter E, Castagna C, Yamamoto A, Yue Z, Arancio O, Peterson BS, Champagne F, Dwork AJ, Goldman J, Sulzer D. Loss of mTOR-dependent macroautophagy causes autistic-like synaptic pruning deficits. Neuron 2014; 83:1131-43. [PMID: 25155956 DOI: 10.1016/j.neuron.2014.07.040] [Citation(s) in RCA: 726] [Impact Index Per Article: 72.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2014] [Indexed: 02/07/2023]
Abstract
Developmental alterations of excitatory synapses are implicated in autism spectrum disorders (ASDs). Here, we report increased dendritic spine density with reduced developmental spine pruning in layer V pyramidal neurons in postmortem ASD temporal lobe. These spine deficits correlate with hyperactivated mTOR and impaired autophagy. In Tsc2 ± ASD mice where mTOR is constitutively overactive, we observed postnatal spine pruning defects, blockade of autophagy, and ASD-like social behaviors. The mTOR inhibitor rapamycin corrected ASD-like behaviors and spine pruning defects in Tsc2 ± mice, but not in Atg7(CKO) neuronal autophagy-deficient mice or Tsc2 ± :Atg7(CKO) double mutants. Neuronal autophagy furthermore enabled spine elimination with no effects on spine formation. Our findings suggest that mTOR-regulated autophagy is required for developmental spine pruning, and activation of neuronal autophagy corrects synaptic pathology and social behavior deficits in ASD models with hyperactivated mTOR.
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Affiliation(s)
- Guomei Tang
- Department of Neurology, Columbia University Medical Center, New York, NY10032, USA
| | - Kathryn Gudsnuk
- Department of Psychology, Columbia University Medical Center, New York, NY10032, USA
| | - Sheng-Han Kuo
- Department of Neurology, Columbia University Medical Center, New York, NY10032, USA
| | - Marisa L Cotrina
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY10032, USA; Center for Translational Neuromedicine, University of Rochester, Rochester, NY 14642, USA
| | - Gorazd Rosoklija
- Department of Psychiatry, Columbia University Medical Center, New York, NY10032, USA; New York State Psychiatric Institute, New York, NY 10032, USA
| | - Alexander Sosunov
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY10032, USA
| | - Mark S Sonders
- Department of Neurology, Columbia University Medical Center, New York, NY10032, USA
| | - Ellen Kanter
- Department of Neurology, Columbia University Medical Center, New York, NY10032, USA
| | - Candace Castagna
- Department of Neurology, Columbia University Medical Center, New York, NY10032, USA
| | - Ai Yamamoto
- Department of Neurology, Columbia University Medical Center, New York, NY10032, USA
| | - Zhenyu Yue
- Departments of Neurology and Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY10032, USA
| | - Bradley S Peterson
- Department of Psychiatry, Columbia University Medical Center, New York, NY10032, USA; New York State Psychiatric Institute, New York, NY 10032, USA
| | - Frances Champagne
- Department of Psychology, Columbia University Medical Center, New York, NY10032, USA
| | - Andrew J Dwork
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY10032, USA; Department of Psychiatry, Columbia University Medical Center, New York, NY10032, USA; New York State Psychiatric Institute, New York, NY 10032, USA
| | - James Goldman
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY10032, USA
| | - David Sulzer
- Department of Neurology, Columbia University Medical Center, New York, NY10032, USA; Department of Psychiatry, Columbia University Medical Center, New York, NY10032, USA; Department of Pharmacology, Columbia University Medical Center, New York, NY10032, USA; New York State Psychiatric Institute, New York, NY 10032, USA.
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23
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Lozovaya N, Gataullina S, Tsintsadze T, Tsintsadze V, Pallesi-Pocachard E, Minlebaev M, Goriounova NA, Buhler E, Watrin F, Shityakov S, Becker AJ, Bordey A, Milh M, Scavarda D, Bulteau C, Dorfmuller G, Delalande O, Represa A, Cardoso C, Dulac O, Ben-Ari Y, Burnashev N. Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model. Nat Commun 2014; 5:4563. [PMID: 25081057 PMCID: PMC4143949 DOI: 10.1038/ncomms5563] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/30/2014] [Indexed: 01/06/2023] Open
Abstract
Tuberous sclerosis complex (TSC), caused by dominant mutations in either
TSC1 or
TSC2 tumour
suppressor genes is characterized by the presence of brain malformations, the
cortical tubers that are thought to contribute to the generation of
pharmacoresistant epilepsy. Here we report that tuberless heterozygote
Tsc1+/− mice show
functional upregulation of cortical GluN2C-containing N-methyl-D-aspartate receptors (NMDARs) in an
mTOR-dependent manner and exhibit recurrent, unprovoked seizures during early
postnatal life (<P19). Seizures are generated intracortically in the granular
layer of the neocortex. Slow kinetics of aberrant GluN2C-mediated currents in spiny stellate cells promotes
excessive temporal integration of persistent NMDAR-mediated recurrent excitation and
seizure generation. Accordingly, specific GluN2C/D antagonists block seizures in Tsc1+/− mice in vivo
and in vitro. Likewise, GluN2C expression is upregulated in TSC human surgical
resections, and a GluN2C/D
antagonist reduces paroxysmal hyperexcitability. Thus, GluN2C receptor constitutes a promising
molecular target to treat epilepsy in TSC patients. Tuberous sclerosis complex (TSC) is a rare genetic condition
characterized by epileptic seizures that start in infancy. Here, the authors show that
these seizures are modulated by GluN2C-containing NMDA receptors in the cortex of a
mouse model of TSC, and that suppressing their activity attenuates seizures.
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Affiliation(s)
- N Lozovaya
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [4]
| | - S Gataullina
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [4]
| | - T Tsintsadze
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3]
| | - V Tsintsadze
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - E Pallesi-Pocachard
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - M Minlebaev
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] Laboratory of Neurobiology, Kazan Federal University, Kremlevskaya street 18, 420000 Kazan, Russia
| | - N A Goriounova
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - E Buhler
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - F Watrin
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - S Shityakov
- Department of Anaesthesia and Critical Care, University of Würzburg, Josef-Schneider-Street 2, 97080 Würzburg, Germany
| | - A J Becker
- Department of Neuropathology, University of Bonn Medical Center, Sigmund Freud Street 25, D-53105 Bonn, Germany
| | - A Bordey
- Neurosurgery, and Cellular and Molecular Physiology Departments, Yale University School of Medicine, PO Box 208082, New Haven, Connecticut 06520-8082, USA
| | - M Milh
- APHM, Department of Pediatric Neurosurgery and Neurology, CHU Timone, 264 Rue Saint-Pierre, 13385 Marseille Cedex 5, France
| | - D Scavarda
- APHM, Department of Pediatric Neurosurgery and Neurology, CHU Timone, 264 Rue Saint-Pierre, 13385 Marseille Cedex 5, France
| | - C Bulteau
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - G Dorfmuller
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - O Delalande
- Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - A Represa
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - C Cardoso
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - O Dulac
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France [3] APHP, Necker Hospital, 149 Rue de Sèvres, 75015 Paris, France
| | - Y Ben-Ari
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - N Burnashev
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
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Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is a genetic multisystem disorder that affects the brain in almost every patient. It is caused by a mutation in the TSC1 or TSC2 genes, which regulate mammalian target of rapamycin (mTOR), a key player in control of cellular growth and protein synthesis. The most frequent neurological symptoms are seizures, which occur in up to 90% of patients and often are intractable, followed by autism spectrum disorders, intellectual disability, attention deficit-hyperactivity disorder, and sleep problems. Conventional treatment has frequently proven insufficient for neurological and behavioral symptoms, particularly seizure control. This review focuses on the role of TSC/mTOR in neuronal development and network formation and recent mechanism-based treatment approaches. METHODS We performed a literature review to identify ongoing therapeutic challenges and novel strategies. RESULTS To achieve a better quality of life for many patients, current therapy approaches are directed at restoring dysregulated mTOR signaling. Studies in animals have provided insight into aberrant neuronal network formation caused by constitutive activation of the mTOR pathway, and initial studies in TSC patients using magnetic resonance diffusion tensor imaging and electroencephalogram support a model of impaired neuronal connectivity in TSC. Rapamycin, an mTOR inhibitor, has been used successfully in Tsc-deficient mice to prevent and treat seizures and behavioral abnormalities. There is recent evidence in humans of improved seizure control with mTOR inhibitors. CONCLUSIONS Current research provides insight into aberrant neuronal connectivity in TSC and the role of mTOR inhibitors as a promising therapeutic approach.
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Affiliation(s)
| | - Mustafa Sahin
- Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
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25
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Desland FA, Afzal A, Warraich Z, Mocco J. Manual versus Automated Rodent Behavioral Assessment: Comparing Efficacy and Ease of Bederson and Garcia Neurological Deficit Scores to an Open Field Video-Tracking System. J Cent Nerv Syst Dis 2014; 6:7-14. [PMID: 24526841 PMCID: PMC3921024 DOI: 10.4137/jcnsd.s13194] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 12/03/2013] [Accepted: 12/14/2013] [Indexed: 11/05/2022] Open
Abstract
Animal models of stroke have been crucial in advancing our understanding of the pathophysiology of cerebral ischemia. Currently, the standards for determining neurological deficit in rodents are the Bederson and Garcia scales, manual assessments scoring animals based on parameters ranked on a narrow scale of severity. Automated open field analysis of a live-video tracking system that analyzes animal behavior may provide a more sensitive test. Results obtained from the manual Bederson and Garcia scales did not show significant differences between pre- and post-stroke animals in a small cohort. When using the same cohort, however, post-stroke data obtained from automated open field analysis showed significant differences in several parameters. Furthermore, large cohort analysis also demonstrated increased sensitivity with automated open field analysis versus the Bederson and Garcia scales. These early data indicate use of automated open field analysis software may provide a more sensitive assessment when compared to traditional Bederson and Garcia scales.
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Affiliation(s)
- Fiona A Desland
- Department of Neurological Surgery, Vanderbilt University, Nashville, TN, USA
| | - Aqeela Afzal
- Department of Neurological Surgery, Vanderbilt University, Nashville, TN, USA
| | - Zuha Warraich
- Department of Neurological Surgery, Vanderbilt University, Nashville, TN, USA
| | - J Mocco
- Department of Neurological Surgery, Vanderbilt University, Nashville, TN, USA
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26
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Cook D, Nuro E, Murai KK. Increasing our understanding of human cognition through the study of Fragile X Syndrome. Dev Neurobiol 2013; 74:147-77. [PMID: 23723176 PMCID: PMC4216185 DOI: 10.1002/dneu.22096] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/17/2013] [Indexed: 12/16/2022]
Abstract
Fragile X Syndrome (FXS) is considered the most common form of inherited intellectual disability. It is caused by reductions in the expression level or function of a single protein, the Fragile X Mental Retardation Protein (FMRP), a translational regulator which binds to approximately 4% of brain messenger RNAs. Accumulating evidence suggests that FXS is a complex disorder of cognition, involving interactions between genetic and environmental influences, leading to difficulties in acquiring key life skills including motor skills, language, and proper social behaviors. Since many FXS patients also present with one or more features of autism spectrum disorders (ASDs), insights gained from studying the monogenic basis of FXS could pave the way to a greater understanding of underlying features of multigenic ASDs. Here we present an overview of the FXS and FMRP field with the goal of demonstrating how loss of a single protein involved in translational control affects multiple stages of brain development and leads to debilitating consequences on human cognition. We also focus on studies which have rescued or improved FXS symptoms in mice using genetic or therapeutic approaches to reduce protein expression. We end with a brief description of how deficits in translational control are implicated in FXS and certain cases of ASDs, with many recent studies demonstrating that ASDs are likely caused by increases or decreases in the levels of certain key synaptic proteins. The study of FXS and its underlying single genetic cause offers an invaluable opportunity to study how a single gene influences brain development and behavior.
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Affiliation(s)
- Denise Cook
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
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27
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Ehninger D. From genes to cognition in tuberous sclerosis: Implications for mTOR inhibitor-based treatment approaches. Neuropharmacology 2013; 68:97-105. [DOI: 10.1016/j.neuropharm.2012.05.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/03/2012] [Accepted: 05/13/2012] [Indexed: 01/27/2023]
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28
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Fu C, Ess KC. Conditional and domain-specific inactivation of the Tsc2 gene in neural progenitor cells. Genesis 2013; 51:284-92. [PMID: 23359422 PMCID: PMC3633697 DOI: 10.1002/dvg.22377] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/16/2013] [Accepted: 01/19/2013] [Indexed: 11/11/2022]
Abstract
Tuberous sclerosis complex (TSC) is a genetic disease characterized by multiorgan benign tumors as well as neurological manifestations. Epilepsy and autism are two of the more prevalent neurological complications and are usually severe. TSC is caused by mutations in either the TSC1 (encodes hamartin) or the TSC2 (encodes tuberin) genes with TSC2 mutations being associated with worse outcomes. Tuberin contains a highly conserved GTPase-activating protein (GAP) domain that indirectly inhibits mammalian target of rapamycin complex 1 (mTORC1). mTORC1 dysregulation is currently thought to cause much of the pathogenesis in TSC but mTORC1-independent mechanisms may also contribute. We generated a novel conditional allele of Tsc2 by flanking exons 36 and 37 with loxP sites. Mice homozygous for this knock-in Tsc2 allele are viable and fertile with normal appearing growth and development. Exposure to Cre recombinase then creates an in-frame deletion involving critical residues of the GAP domain. Homozygous conditional mutant mice generated using Emx1(Cre) have increased cortical mTORC1 signaling, severe developmental brain anomalies, seizures, and die within 3 weeks. We found that the normal levels of the mutant Tsc2 mRNA, though GAP-deficient tuberin protein, appear unstable and rapidly degraded. This novel animal model will allow further study of tuberin function including the requirement of the GAP domain for protein stability.
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Affiliation(s)
- Cary Fu
- Divisions of Child Neurology and Epilepsy, Department of Neurology, Vanderbilt Kennedy Center, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 USA
| | - Kevin C. Ess
- Divisions of Child Neurology and Epilepsy, Department of Neurology, Vanderbilt Kennedy Center, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 USA
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29
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Feliciano DM, Lin TV, Hartman NW, Bartley CM, Kubera C, Hsieh L, Lafourcade C, O'Keefe RA, Bordey A. A circuitry and biochemical basis for tuberous sclerosis symptoms: from epilepsy to neurocognitive deficits. Int J Dev Neurosci 2013; 31:667-78. [PMID: 23485365 DOI: 10.1016/j.ijdevneu.2013.02.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/15/2013] [Accepted: 02/18/2013] [Indexed: 01/17/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant monogenetic disorder that is characterized by the formation of benign tumors in several organs as well as brain malformations and neuronal defects. TSC is caused by inactivating mutations in one of two genes, TSC1 and TSC2, resulting in increased activity of the mammalian Target of Rapamycin (mTOR). Here, we explore the cytoarchitectural and functional CNS aberrations that may account for the neurological presentations of TSC, notably seizures, hydrocephalus, and cognitive and psychological impairments. In particular, recent mouse models of brain lesions are presented with an emphasis on using electroporation to allow the generation of discrete lesions resulting from loss of heterozygosity during perinatal development. Cortical lesions are thought to contribute to epileptogenesis and worsening of cognitive defects. However, it has recently been suggested that being born with a mutant allele without loss of heterozygosity and associated cortical lesions is sufficient to generate cognitive and neuropsychiatric problems. We will thus discuss the function of mTOR hyperactivity on neuronal circuit formation and the potential consequences of being born heterozygous on neuronal function and the biochemistry of synaptic plasticity, the cellular substrate of learning and memory. Ultimately, a major goal of TSC research is to identify the cellular and molecular mechanisms downstream of mTOR underlying the neurological manifestations observed in TSC patients and identify novel therapeutic targets to prevent the formation of brain lesions and restore neuronal function.
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Affiliation(s)
- David M Feliciano
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
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30
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Santini E, Huynh TN, MacAskill AF, Carter AG, Pierre P, Ruggero D, Kaphzan H, Klann E. Exaggerated translation causes synaptic and behavioural aberrations associated with autism. Nature 2013; 493:411-5. [PMID: 23263185 PMCID: PMC3548017 DOI: 10.1038/nature11782] [Citation(s) in RCA: 269] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 11/12/2012] [Indexed: 12/27/2022]
Abstract
Autism spectrum disorders (ASDs) are an early onset, heterogeneous group of heritable neuropsychiatric disorders with symptoms that include deficits in social interaction skills, impaired communication abilities, and ritualistic-like repetitive behaviours. One of the hypotheses for a common molecular mechanism underlying ASDs is altered translational control resulting in exaggerated protein synthesis. Genetic variants in chromosome 4q, which contains the EIF4E locus, have been described in patients with autism. Importantly, a rare single nucleotide polymorphism has been identified in autism that is associated with increased promoter activity in the EIF4E gene. Here we show that genetically increasing the levels of eukaryotic translation initiation factor 4E (eIF4E) in mice results in exaggerated cap-dependent translation and aberrant behaviours reminiscent of autism, including repetitive and perseverative behaviours and social interaction deficits. Moreover, these autistic-like behaviours are accompanied by synaptic pathophysiology in the medial prefrontal cortex, striatum and hippocampus. The autistic-like behaviours displayed by the eIF4E-transgenic mice are corrected by intracerebroventricular infusions of the cap-dependent translation inhibitor 4EGI-1. Our findings demonstrate a causal relationship between exaggerated cap-dependent translation, synaptic dysfunction and aberrant behaviours associated with autism.
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Affiliation(s)
- Emanuela Santini
- Center for Neural Science, New York University, New York, New York 10003, USA
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31
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Chung L, Bey AL, Jiang YH. Synaptic plasticity in mouse models of autism spectrum disorders. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2012; 16:369-78. [PMID: 23269898 PMCID: PMC3526740 DOI: 10.4196/kjpp.2012.16.6.369] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 10/27/2012] [Accepted: 10/28/2012] [Indexed: 12/03/2022]
Abstract
Analysis of synaptic plasticity together with behavioral and molecular studies have become a popular approach to model autism spectrum disorders in order to gain insight into the pathosphysiological mechanisms and to find therapeutic targets. Abnormalities of specific types of synaptic plasticity have been revealed in numerous genetically modified mice that have molecular construct validity to human autism spectrum disorders. Constrained by the feasibility of technique, the common regions analyzed in most studies are hippocampus and visual cortex. The relevance of the synaptic defects in these regions to the behavioral abnormalities of autistic like behaviors is still a subject of debate. Because the exact regions or circuits responsible for the core features of autistic behaviors in humans are still poorly understood, investigation using region-specific conditional mutant mice may help to provide the insight into the neuroanatomical basis of autism in the future.
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Affiliation(s)
- Leeyup Chung
- Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
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32
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Reith RM, McKenna J, Wu H, Hashmi SS, Cho SH, Dash PK, Gambello MJ. Loss of Tsc2 in Purkinje cells is associated with autistic-like behavior in a mouse model of tuberous sclerosis complex. Neurobiol Dis 2012; 51:93-103. [PMID: 23123587 DOI: 10.1016/j.nbd.2012.10.014] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/19/2012] [Accepted: 10/13/2012] [Indexed: 12/17/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a dominant tumor suppressor disorder caused by mutations in either TSC1 or TSC2. TSC causes substantial neuropathology, often leading to autism spectrum disorders (ASDs) in up to 60% of patients. The anatomic and neurophysiologic links between these two disorders are not well understood. We have generated and characterized a novel TSC mouse model with Purkinje cell specific Tsc2 loss. These Tsc2f/-;Cre mice exhibit progressive Purkinje cell degeneration. Since loss of Purkinje cells is a well reported postmortem finding in patients with ASD, we conducted a series of behavior tests to asses if Tsc2f/-;Cre mice displayed autistic-like deficits. Tsc2f/-;Cre mice demonstrated increased repetitive behavior as assessed with marble burying activity. Using the three chambered apparatus to asses social behavior, we found that Tsc2f/-;Cre mice showed behavioral deficits, exhibiting no preference between a stranger mouse and an inanimate object, or between a novel and a familiar mouse. We also detected social deficits in Tsc2f/f;Cre mice, suggesting that Purkinje cell pathology is sufficient to induce ASD-like behavior. Importantly, social behavior deficits were prevented with rapamycin treatment. Altogether, these results demonstrate that loss of Tsc2 in Purkinje cells in a Tsc2-haploinsufficient background leads to autistic-like behavioral deficits. These studies provide compelling evidence that Purkinje cell loss and/or dysfunction may be an important link between TSC and ASD as well as a general anatomic phenomenon that contributes to the ASD phenotype.
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Affiliation(s)
- R Michelle Reith
- Program in Human and Molecular Genetics, UT Health, Houston, TX, USA
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33
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Meyza KZ, Defensor EB, Jensen AL, Corley MJ, Pearson BL, Pobbe RLH, Bolivar VJ, Blanchard DC, Blanchard RJ. The BTBR T+ tf/J mouse model for autism spectrum disorders-in search of biomarkers. Behav Brain Res 2012; 251:25-34. [PMID: 22958973 DOI: 10.1016/j.bbr.2012.07.021] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/11/2012] [Accepted: 07/12/2012] [Indexed: 12/28/2022]
Abstract
Autism spectrum disorders (ASD) form a common group of neurodevelopmental disorders appearing to be under polygenic control, but also strongly influenced by multiple environmental factors. The brain mechanisms responsible for ASD are not understood and animal models paralleling related emotional and cognitive impairments may prove helpful in unraveling them. BTBR T+ tf/J (BTBR) mice display behaviors consistent with the three diagnostic categories for ASD. They show impaired social interaction and communication as well as increased repetitive behaviors. This review covers much of the data available to date on BTBR behavior, neuroanatomy and physiology in search for candidate biomarkers, which could both serve as diagnostic tools and help to design effective treatments for the behavioral symptoms of ASD.
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Affiliation(s)
- Ksenia Z Meyza
- Pacific Biosciences Research Center, University of Hawaii, 1993 East-west Road, Honolulu, HI 96822, USA
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34
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Synaptic plasticity and learning in animal models of tuberous sclerosis complex. Neural Plast 2012; 2012:279834. [PMID: 22848848 PMCID: PMC3403083 DOI: 10.1155/2012/279834] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/11/2012] [Accepted: 05/16/2012] [Indexed: 11/17/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is caused by a mutation of either the Tsc1 or Tsc2 gene. As these genes work in concert to negatively regulate the mammalian target of rapamycin (mTOR) kinase which is involved in protein translation, mutations of these genes lead to a disinhibited mTOR activity. Both the clinical appearance of this condition including tumors, cognitive decline, and epileptic seizures and the molecular understanding of the mTOR signaling pathway, not only involved in cell growth, but also in neuronal functioning, have inspired numerous studies on learning behavior as well as on synaptic plasticity which is the key molecular mechanism of information storage in the brain. A couple of interesting animal models have been established, and the data obtained in these animals will be discussed. A special focus will be laid on differences among these models, which may be in part due to different background strains, but also may indicate pathophysiological variation in different mutations.
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35
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The interaction between early life epilepsy and autistic-like behavioral consequences: a role for the mammalian target of rapamycin (mTOR) pathway. PLoS One 2012; 7:e35885. [PMID: 22567115 PMCID: PMC3342334 DOI: 10.1371/journal.pone.0035885] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 03/23/2012] [Indexed: 12/14/2022] Open
Abstract
Early life seizures can result in chronic epilepsy, cognitive deficits and behavioral changes such as autism, and conversely epilepsy is common in autistic children. We hypothesized that during early brain development, seizures could alter regulators of synaptic development and underlie the interaction between epilepsy and autism. The mammalian Target of Rapamycin (mTOR) modulates protein translation and is dysregulated in Tuberous Sclerosis Complex, a disorder characterized by epilepsy and autism. We used a rodent model of acute hypoxia-induced neonatal seizures that results in long term increases in neuronal excitability, seizure susceptibility, and spontaneous seizures, to determine how seizures alter mTOR Complex 1 (mTORC1) signaling. We hypothesized that seizures occurring at a developmental stage coinciding with a critical period of synaptogenesis will activate mTORC1, contributing to epileptic networks and autistic-like behavior in later life. Here we show that in the rat, baseline mTORC1 activation peaks during the first three postnatal weeks, and induction of seizures at postnatal day 10 results in further transient activation of its downstream targets phospho-4E-BP1 (Thr37/46), phospho-p70S6K (Thr389) and phospho-S6 (Ser235/236), as well as rapid induction of activity-dependent upstream signaling molecules, including BDNF, phospho-Akt (Thr308) and phospho-ERK (Thr202/Tyr204). Furthermore, treatment with the mTORC1 inhibitor rapamycin immediately before and after seizures reversed early increases in glutamatergic neurotransmission and seizure susceptibility and attenuated later life epilepsy and autistic-like behavior. Together, these findings suggest that in the developing brain the mTORC1 signaling pathway is involved in epileptogenesis and altered social behavior, and that it may be a target for development of novel therapies that eliminate the progressive effects of neonatal seizures.
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36
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Chévere-Torres I, Kaphzan H, Bhattacharya A, Kang A, Maki JM, Gambello MJ, Arbiser JL, Santini E, Klann E. Metabotropic glutamate receptor-dependent long-term depression is impaired due to elevated ERK signaling in the ΔRG mouse model of tuberous sclerosis complex. Neurobiol Dis 2011; 45:1101-10. [PMID: 22198573 DOI: 10.1016/j.nbd.2011.12.028] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 11/08/2011] [Accepted: 12/08/2011] [Indexed: 11/28/2022] Open
Abstract
Tuberous sclerosis complex (TSC) and fragile X syndrome (FXS) are caused by mutations in negative regulators of translation. FXS model mice exhibit enhanced metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD). Therefore, we hypothesized that a mouse model of TSC, ΔRG transgenic mice, also would exhibit enhanced mGluR-LTD. We measured the impact of TSC2-GAP mutations on the mTORC1 and ERK signaling pathways and protein synthesis-dependent hippocampal synaptic plasticity in ΔRG transgenic mice. These mice express a dominant/negative TSC2 that binds to TSC1, but has a deletion and substitution mutation in its GAP-domain, resulting in inactivation of the complex. Consistent with previous studies of several other lines of TSC model mice, we observed elevated S6 phosphorylation in the brains of ΔRG mice, suggesting upregulated translation. Surprisingly, mGluR-LTD was not enhanced, but rather was impaired in the ΔRG transgenic mice, indicating that TSC and FXS have divergent synaptic plasticity phenotypes. Similar to patients with TSC, the ΔRG transgenic mice exhibit elevated ERK signaling. Moreover, the mGluR-LTD impairment displayed by the ΔRG transgenic mice was rescued with the MEK-ERK inhibitor U0126. Our results suggest that the mGluR-LTD impairment observed in ΔRG mice involves aberrant TSC1/2-ERK signaling.
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37
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Santini E, Klann E. Dysregulated mTORC1-Dependent Translational Control: From Brain Disorders to Psychoactive Drugs. Front Behav Neurosci 2011; 5:76. [PMID: 22073033 PMCID: PMC3210466 DOI: 10.3389/fnbeh.2011.00076] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/21/2011] [Indexed: 01/09/2023] Open
Abstract
In the last decade, a plethora of studies utilizing pharmacological, biochemical, and genetic approaches have shown that precise translational control is required for long-lasting synaptic plasticity and the formation of long-term memory. Moreover, more recent studies indicate that alterations in translational control are a common pathophysiological feature of human neurological disorders, including developmental disorders, neuropsychiatric disorders, and neurodegenerative diseases. Finally, translational control mechanisms are susceptible to modification by psychoactive drugs. Taken together, these findings point to a central role for translational control in the regulation of synaptic function and behavior.
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Affiliation(s)
- Emanuela Santini
- Center for Neural Science, New York University New York, NY, USA
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