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Baset A, Huang F. Shedding light on subiculum's role in human brain disorders. Brain Res Bull 2024; 214:110993. [PMID: 38825254 DOI: 10.1016/j.brainresbull.2024.110993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 05/17/2024] [Accepted: 05/30/2024] [Indexed: 06/04/2024]
Abstract
Subiculum is a pivotal output component of the hippocampal formation, a structure often overlooked in neuroscientific research. Here, this review aims to explore the role of the subiculum in various brain disorders, shedding light on its significance within the functional-neuroanatomical perspective on neurological diseases. The subiculum's involvement in multiple brain disorders was thoroughly examined. In Alzheimer's disease, subiculum alterations precede cognitive decline, while in epilepsy, the subiculum plays a critical role in seizure initiation. Stress involves the subiculum's impact on the hypothalamic-pituitary-adrenocortical axis. Moreover, the subiculum exhibits structural and functional changes in anxiety, schizophrenia, and Parkinson's disease, contributing to cognitive deficits. Bipolar disorder is linked to subiculum structural abnormalities, while autism spectrum disorder reveals an alteration of inward deformation in the subiculum. Lastly, frontotemporal dementia shows volumetric differences in the subiculum, emphasizing its contribution to the disorder's complexity. Taken together, this review consolidates existing knowledge on the subiculum's role in brain disorders, and may facilitate future research, diagnostic strategies, and therapeutic interventions for various neurological conditions.
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Affiliation(s)
- Abdul Baset
- Department of Neuroscience, City University of Hong Kong, Hong Kong Special Administrative Region of China; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong Special Administrative Region of China
| | - Fengwen Huang
- Department of Neuroscience, City University of Hong Kong, Hong Kong Special Administrative Region of China; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong Special Administrative Region of China.
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2
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Johnson AJ, Shankland E, Richards T, Corrigan N, Shusterman D, Edden R, Estes A, St John T, Dager S, Kleinhans NM. Relationships between GABA, glutamate, and GABA/glutamate and social and olfactory processing in children with autism spectrum disorder. Psychiatry Res Neuroimaging 2023; 336:111745. [PMID: 37956467 PMCID: PMC10841920 DOI: 10.1016/j.pscychresns.2023.111745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023]
Abstract
Theories of altered inhibitory/excitatory signaling in autism spectrum disorder (ASD) suggest that gamma amino butyric acid (GABA) and glutamate (Glu) abnormalities may underlie social and sensory challenges in ASD. Magnetic resonance spectroscopy was used to measure Glu and GABA+ levels in the amygdala-hippocampus region and cerebellum in autistic children (n = 30), a clinical control group with sensory abnormalities (SA) but not ASD (n = 30), and children with typical development (n = 37). All participants were clinically assessed using the Autism Diagnostic Interview-Revised, the Autism Diagnostic Observation Scale-2, and the Child Sensory Profile-2. The Social Responsiveness Scale-2, Sniffin Sticks Threshold Test, and the University of Pennsylvania Smell Identification Test were administered to assess social impairment and olfactory processing. Overall, autistic children showed increased cerebellar Glu levels compared to TYP children. Evidence for altered excitatory/inhibitory signaling in the cerebellum was more clear-cut when analyses were restricted to male participants. Further, lower cerebellar GABA+/Glu ratios were correlated to more severe social impairment in both autistic and SA males, suggesting that the cerebellum may play a transdiagnostic role in social impairment. Future studies of inhibitory/excitatory neural markers, powered to investigate the role of sex, may aid in parsing out disorder-specific neurochemical profiles.
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Affiliation(s)
- Allegra J Johnson
- Department of Radiology, University of Washington, USA; Integrated Brain Imaging Center (IBIC), University of Washington, Box 357115, 1959 NE Pacific St, Seattle, WA 98195, USA
| | | | - Todd Richards
- Department of Radiology, University of Washington, USA; Integrated Brain Imaging Center (IBIC), University of Washington, Box 357115, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Neva Corrigan
- Institute on Human Development and Disability (IHDD), University of Washington, USA
| | - Dennis Shusterman
- Department of Medicine, University of California, San Francisco, USA
| | - Richard Edden
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, USA; F.M. Kirby Center for Functional MRI, Kennedy Krieger Institute, USA
| | - Annette Estes
- Institute on Human Development and Disability (IHDD), University of Washington, USA; Department of Speech and Hearing Sciences, University of Washington, USA; University of Washington Autism Center, USA
| | - Tanya St John
- University of Washington Autism Center, USA; Department of Medicine, University of California, San Francisco, USA
| | - Stephen Dager
- Department of Radiology, University of Washington, USA; Institute on Human Development and Disability (IHDD), University of Washington, USA; Department of Biomedical Engineering, University of Washington, USA
| | - Natalia M Kleinhans
- Department of Radiology, University of Washington, USA; Integrated Brain Imaging Center (IBIC), University of Washington, Box 357115, 1959 NE Pacific St, Seattle, WA 98195, USA; Institute on Human Development and Disability (IHDD), University of Washington, USA.
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3
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Nardi L, Chhabra S, Leukel P, Krueger-Burg D, Sommer CJ, Schmeisser MJ. Neuroanatomical changes of ionotropic glutamatergic and GABAergic receptor densities in male mice modeling idiopathic and syndromic autism spectrum disorder. Front Psychiatry 2023; 14:1199097. [PMID: 37547211 PMCID: PMC10401048 DOI: 10.3389/fpsyt.2023.1199097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/29/2023] [Indexed: 08/08/2023] Open
Abstract
Autism spectrum disorder (ASD) comprises a wide range of neurodevelopment conditions primarily characterized by impaired social interaction and repetitive behavior, accompanied by a variable degree of neuropsychiatric characteristics. Synaptic dysfunction is undertaken as one of the key underlying mechanisms in understanding the pathophysiology of ASD. The excitatory/inhibitory (E/I) hypothesis is one of the most widely held theories for its pathogenesis. Shifts in E/I balance have been proven in several ASD models. In this study, we investigated three mouse lines recapitulating both idiopathic (the BTBR strain) and genetic (Fmr1 and Shank3 mutants) forms of ASD at late infancy and early adulthood. Using receptor autoradiography for ionotropic excitatory (AMPA and NMDA) and inhibitory (GABAA) receptors, we mapped the receptor binding densities in brain regions known to be associated with ASD such as prefrontal cortex, dorsal and ventral striatum, dorsal hippocampus, and cerebellum. The individual mouse lines investigated show specific alterations in excitatory ionotropic receptor density, which might be accounted as specific hallmark of each individual line. Across all the models investigated, we found an increased binding density to GABAA receptors at adulthood in the dorsal hippocampus. Interestingly, reduction in the GABAA receptor binding density was observed in the cerebellum. Altogether, our findings suggest that E/I disbalance individually affects several brain regions in ASD mouse models and that alterations in GABAergic transmission might be accounted as unifying factor.
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Affiliation(s)
- Leonardo Nardi
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Stuti Chhabra
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Petra Leukel
- Institute of Neuropathology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Dilja Krueger-Burg
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Clemens J. Sommer
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
- Institute of Neuropathology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Michael J. Schmeisser
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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4
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Zhao H, Mao X, Zhu C, Zou X, Peng F, Yang W, Li B, Li G, Ge T, Cui R. GABAergic System Dysfunction in Autism Spectrum Disorders. Front Cell Dev Biol 2022; 9:781327. [PMID: 35198562 PMCID: PMC8858939 DOI: 10.3389/fcell.2021.781327] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/16/2021] [Indexed: 12/19/2022] Open
Abstract
Autism spectrum disorder (ASD) refers to a series of neurodevelopmental diseases characterized by two hallmark symptoms, social communication deficits and repetitive behaviors. Gamma-aminobutyric acid (GABA) is one of the most important inhibitory neurotransmitters in the central nervous system (CNS). GABAergic inhibitory neurotransmission is critical for the regulation of brain rhythm and spontaneous neuronal activities during neurodevelopment. Genetic evidence has identified some variations of genes associated with the GABA system, indicating an abnormal excitatory/inhibitory (E/I) neurotransmission ratio implicated in the pathogenesis of ASD. However, the specific molecular mechanism by which GABA and GABAergic synaptic transmission affect ASD remains unclear. Transgenic technology enables translating genetic variations into rodent models to further investigate the structural and functional synaptic dysregulation related to ASD. In this review, we summarized evidence from human neuroimaging, postmortem, and genetic and pharmacological studies, and put emphasis on the GABAergic synaptic dysregulation and consequent E/I imbalance. We attempt to illuminate the pathophysiological role of structural and functional synaptic dysregulation in ASD and provide insights for future investigation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ranji Cui
- *Correspondence: Tongtong Ge, ; Ranji Cui,
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5
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Dysfunction of Trio GEF1 involves in excitatory/inhibitory imbalance and autism-like behaviors through regulation of interneuron migration. Mol Psychiatry 2021; 26:7621-7640. [PMID: 33963279 DOI: 10.1038/s41380-021-01109-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/24/2021] [Accepted: 04/08/2021] [Indexed: 02/03/2023]
Abstract
Autism spectrum disorders (ASDs) are a group of highly inheritable neurodevelopmental disorders. Functional mutations in TRIO, especially in the GEF1 domain, are strongly implicated in ASDs, whereas the underlying neurobiological pathogenesis and molecular mechanisms remain to be clarified. Here we characterize the abnormal morphology and behavior of embryonic migratory interneurons (INs) upon Trio deficiency or GEF1 mutation in mice, which are mediated by the Trio GEF1-Rac1 activation and involved in SDF1α/CXCR4 signaling. In addition, the migration deficits are specifically associated with altered neural microcircuit, decreased inhibitory neurotransmission, and autism-like behaviors, which are reminiscent of some features observed in patients with ASDs. Furthermore, restoring the excitatory/inhibitory (E/I) imbalance via activation of GABA signaling rescues autism-like deficits. Our findings demonstrate a critical role of Trio GEF1 mediated signaling in IN migration and E/I balance, which are related to autism-related behavioral phenotypes.
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Paterno R, Marafiga JR, Ramsay H, Li T, Salvati KA, Baraban SC. Hippocampal gamma and sharp-wave ripple oscillations are altered in a Cntnap2 mouse model of autism spectrum disorder. Cell Rep 2021; 37:109970. [PMID: 34758298 PMCID: PMC8783641 DOI: 10.1016/j.celrep.2021.109970] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/02/2021] [Accepted: 10/19/2021] [Indexed: 01/02/2023] Open
Abstract
Impaired synaptic neurotransmission may underly circuit alterations contributing to behavioral autism spectrum disorder (ASD) phenotypes. A critical component of impairments reported in somatosensory and prefrontal cortex of ASD mouse models are parvalbumin (PV)-expressing fast-spiking interneurons. However, it remains unknown whether PV interneurons mediating hippocampal networks crucial to navigation and memory processing are similarly impaired. Using PV-labeled transgenic mice, a battery of behavioral assays, in vitro patch-clamp electrophysiology, and in vivo 32-channel silicon probe local field potential recordings, we address this question in a Cntnap2-null mutant mouse model representing a human ASD risk factor gene. Cntnap2-/- mice show a reduction in hippocampal PV interneuron density, reduced inhibitory input to CA1 pyramidal cells, deficits in spatial discrimination ability, and frequency-dependent circuit changes within the hippocampus, including alterations in gamma oscillations, sharp-wave ripples, and theta-gamma modulation. Our findings highlight hippocampal involvement in ASD and implicate interneurons as a potential therapeutical target.
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Affiliation(s)
- Rosalia Paterno
- Department of Neurological Surgery and Weill Institute of Neuroscience, University of California, San Francisco, CA 94143, USA.
| | - Joseane Righes Marafiga
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90035-003, Brazil
| | - Harrison Ramsay
- Department of Neurological Surgery and Weill Institute of Neuroscience, University of California, San Francisco, CA 94143, USA
| | - Tina Li
- Department of Neurological Surgery and Weill Institute of Neuroscience, University of California, San Francisco, CA 94143, USA
| | - Kathryn A Salvati
- Department of Neurological Surgery and Weill Institute of Neuroscience, University of California, San Francisco, CA 94143, USA
| | - Scott C Baraban
- Department of Neurological Surgery and Weill Institute of Neuroscience, University of California, San Francisco, CA 94143, USA
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7
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Yang JQ, Yang CH, Yin BQ. Combined the GABA-A and GABA-B receptor agonists attenuates autistic behaviors in a prenatal valproic acid-induced mouse model of autism. Behav Brain Res 2021; 403:113094. [PMID: 33359845 DOI: 10.1016/j.bbr.2020.113094] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/08/2020] [Accepted: 12/19/2020] [Indexed: 01/18/2023]
Abstract
Autism spectrum disorder (ASD) is an immensely challenging developmental disorder characterized primarily by two core behavioral symptoms of social communication deficits and restricted/repetitive behaviors. Investigating the etiological process and identifying an appropriate therapeutic target remain as formidable challenges to overcome ASD due to numerous risk factors and complex symptoms associated with the disorder. Among the various mechanisms that contribute to ASD, the maintenance of excitation and inhibition balance emerged as a key factor to regulate proper functioning of neuronal circuitry. In this study, we employed prenatally exposed to valproic acid (VPA) to establish a validated ASD mouse model and found impaired inhibitory gamma-aminobutyric acid (GABAergic) neurotransmission through a presynaptic mechanism in these model mice, which was accompanied with decreased GABA release and GABA-A and GABA-B receptor subunits expression. And acute administration of individual GABA-A or GABA-B receptor agonists partially reversed autistic-like behaviors in the model mice. Furthermore, acute administration of the combined GABA-A and GABA-B receptor agonists palliated sociability deficits, anxiety and repetitive behaviors in the animal model of autistic-like behaviors, demonstrating the therapeutic potential of above cocktail in the treatment of ASD.
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Affiliation(s)
- Jian-Quan Yang
- Department of Children Rehabilitation, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Chao-Hua Yang
- Department of Children Rehabilitation, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Bao-Qi Yin
- Department of Children Rehabilitation, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
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Brandenburg C, Soghomonian JJ, Zhang K, Sulkaj I, Randolph B, Kachadoorian M, Blatt GJ. Increased Dopamine Type 2 Gene Expression in the Dorsal Striatum in Individuals With Autism Spectrum Disorder Suggests Alterations in Indirect Pathway Signaling and Circuitry. Front Cell Neurosci 2020; 14:577858. [PMID: 33240045 PMCID: PMC7681004 DOI: 10.3389/fncel.2020.577858] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/09/2020] [Indexed: 12/22/2022] Open
Abstract
Autism spectrum disorder (ASD) is behaviorally defined and diagnosed by delayed and/or impeded language, stereotyped repetitive behaviors, and difficulties with social interactions. Additionally, there are disruptions in motor processing, which includes the intent to execute movements, interrupted/inhibited action chain sequences, impaired execution of speech, and repetitive motor behaviors. Cortical loops through basal ganglia (BG) structures are known to play critical roles in the typical functioning of these actions. Specifically, corticostriate projections to the dorsal striatum (caudate and putamen) convey abundant input from motor, cognitive and limbic cortices and subsequently project to other BG structures. Excitatory dopamine (DA) type 1 receptors are predominantly expressed on GABAergic medium spiny neurons (MSNs) in the dorsal striatum as part of the "direct pathway" to GPi and SNpr whereas inhibitory DA type 2 receptors are predominantly expressed on MSNs that primarily project to GPe. This study aimed to better understand how this circuitry may be altered in ASD, especially concerning the neurochemical modulation of GABAergic MSNs within the two major BG pathways. We utilized two classical methods to analyze the postmortem BG in ASD in comparison to neurotypical cases: ligand binding autoradiography to quantify densities of GABA-A, GABA-B, 5-HT2, and DA type 1 and 2 receptors and in situ hybridization histochemistry (ISHH) to quantify mRNA for D1, D2 receptors and three key GABAergic subunits (α1, β2, and γ2), as well as the GABA synthesizing enzymes (GAD65/67). Results demonstrated significant increases in D2 mRNA within MSNs in both the caudate and putamen, which was further verified by proenkephalin mRNA that is co-expressed with the D2 receptor in the indirect pathway MSNs. In contrast, all other GABAergic, serotonergic and dopaminergic markers in the dorsal striatum had comparable labeling densities. These results indicate alterations in the indirect pathway of the BG, with possible implications for the execution of competing motor programs and E/I imbalance in the direct/indirect motor feedback pathways through thalamic and motor cortical areas. Results also provide insights regarding the efficacy of FDA-approved drugs used to treat individuals with ASD acting on specific DA and 5-HT receptor subtypes.
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Affiliation(s)
- Cheryl Brandenburg
- Autism Neurocircuitry Laboratory, Hussman Institute for Autism, Baltimore, MD, United States.,Program in Neuroscience, University of Maryland Baltimore School of Medicine, Baltimore, MD, United States
| | - Jean-Jacques Soghomonian
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Kunzhong Zhang
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Ina Sulkaj
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Brianna Randolph
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Marissa Kachadoorian
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Gene J Blatt
- Autism Neurocircuitry Laboratory, Hussman Institute for Autism, Baltimore, MD, United States
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Di J, Li J, O’Hara B, Alberts I, Xiong L, Li J, Li X. The role of GABAergic neural circuits in the pathogenesis of autism spectrum disorder. Int J Dev Neurosci 2020; 80:73-85. [DOI: 10.1002/jdn.10005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 12/13/2019] [Indexed: 12/21/2022] Open
Affiliation(s)
- Jing Di
- Department of Neurology David Geffen School of Medicine at UCLA Los Angeles CA USA
| | - Jian Li
- Department of Pediatrics the Second Xiangya HospitalCentral South University Changsha P.R. China
| | - Bruce O’Hara
- Department of Biology University of Kentucky Lexington KY USA
| | - Ian Alberts
- Department of Natural Sciences LaGuardia CCCUNY New York NY USA
| | - Lei Xiong
- Department of Clinical Medicine Yunnan University of Chinese Medicine Kunming P.R. China
| | - Jijun Li
- Department of Integrative Medicine on Pediatrics Shanghai Children’s Medical Center Shanghai Jiao Tong University School of Medicine Shanghai P.R. China
| | - Xiaohong Li
- Department of Neurochemistry New York State Institute for Basic Research in Developmental Disabilities New York NY USA
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Microbiota changes associated with ADNP deficiencies: rapid indicators for NAP (CP201) treatment of the ADNP syndrome and beyond. J Neural Transm (Vienna) 2020; 127:251-263. [PMID: 32072336 PMCID: PMC7035218 DOI: 10.1007/s00702-020-02155-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 01/20/2020] [Indexed: 12/31/2022]
Abstract
Activity-dependent neuroprotective protein (ADNP) and its protein snippet NAP (drug candidate CP201) regulate synapse formation and cognitive as well as behavioral functions, in part, through microtubule interaction. Given potential interactions between the microbiome and brain function, we now investigated the potential effects of the ADNP-deficient genotype, mimicking the ADNP syndrome on microbiota composition in the Adnp+/– mouse model. We have discovered a surprising robust sexually dichotomized Adnp genotype effect and correction by NAP (CP201) as follows. Most of the commensal bacterial microbiota tested were affected by the Adnp genotype and corrected by NAP treatment in a male sex-dependent manner. The following list includes all the bacterial groups tested—labeled in bold are male Adnp—genotype increased and corrected (decreased) by NAP. (1) Eubacteriaceae (EubV3), (2) Enterobacteriaceae (Entero), (3) Enterococcus genus (gEncocc), (4) Lactobacillus group (Lacto), (5) Bifidobacterium genus (BIF), (6) Bacteroides/Prevotella species (Bac), (7) Clostridium coccoides group (Coer), (8) Clostridium leptum group (Cluster IV, sgClep), and (9) Mouse intestinal Bacteroides (MIB). No similarities were found between males and females regarding sex- and genotype-dependent microbiota distributions. Furthermore, a female Adnp+/– genotype associated decrease (contrasting male increase) was observed in the Lactobacillus group (Lacto). Significant correlations were discovered between specific bacterial group loads and open-field behavior as well as social recognition behaviors. In summary, we discovered ADNP deficiency associated changes in commensal gut microbiota compositions, a sex-dependent biomarker for the ADNP syndrome and beyond. Strikingly, we discovered rapidly detected NAP (CP201) treatment-dependent biomarkers within the gut microbiota.
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Schafer M, Schiller D. The Hippocampus and Social Impairment in Psychiatric Disorders. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2019; 83:105-118. [PMID: 30787048 DOI: 10.1101/sqb.2018.83.037614] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Social deficits, such as poor social skills (i.e., the inability to engage in appropriate and effective social interactions) and social withdrawal, are prevalent across psychiatric disorders and often co-occur with hippocampal structural and functional abnormalities. The centrality of both social and hippocampal dysfunction in psychiatric research prompts the question: Are they linked? The social cognitive map framework provides a clue: The hippocampus tracks social information in the physical environment, maps others along social dimensions, and supports social memory and decision-making. Hippocampal dysfunction might disrupt social map representation and contribute to commonly seen social behavioral symptoms. This review summarizes evidence for the role of the hippocampus in social cognitive mapping, followed by evidence that hippocampal dysfunction and social dysfunction co-occur in psychiatric disorders. We argue that the co-occurrence of hippocampal and social impairment may be related via hippocampal social cognitive mapping.
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Affiliation(s)
- Matthew Schafer
- Department of Psychiatry, Department of Neuroscience, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Daniela Schiller
- Department of Psychiatry, Department of Neuroscience, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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12
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Li Z, Jagadapillai R, Gozal E, Barnes G. Deletion of Semaphorin 3F in Interneurons Is Associated with Decreased GABAergic Neurons, Autism-like Behavior, and Increased Oxidative Stress Cascades. Mol Neurobiol 2019; 56:5520-5538. [PMID: 30635860 PMCID: PMC6614133 DOI: 10.1007/s12035-018-1450-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/07/2018] [Indexed: 12/11/2022]
Abstract
Autism and epilepsy are diseases which have complex genetic inheritance. Genome-wide association and other genetic studies have implicated at least 500+ genes associated with the occurrence of autism spectrum disorders (ASD) including the human semaphorin 3F (Sema 3F) and neuropilin 2 (NRP2) genes. However, the genetic basis of the comorbid occurrence of autism and epilepsy is unknown. The aberrant development of GABAergic circuitry is a possible risk factor in autism and epilepsy. Molecular biological approaches were used to test the hypothesis that cell-specific genetic variation in mouse homologs affects the formation and function of GABAergic circuitry. The empirical analysis with mice homozygous null for one of these genes, Sema 3F, in GABAergic neurons substantiated these predictions. Notably, deletion of Sema 3F in interneurons but not excitatory neurons during early development decreased the number of interneurons/neurites and mRNAs for cell-specific GABAergic markers and increased epileptogenesis and autistic behaviors. Studies of interneuron cell-specific knockout of Sema 3F signaling suggest that deficient Sema 3F signaling may lead to neuroinflammation and oxidative stress. Further studies of mouse KO models of ASD genes such as Sema 3F or NRP2 may be informative to clinical phenotypes contributing to the pathogenesis in autism and epilepsy patients.
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Affiliation(s)
- Zhu Li
- Department of Neurology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Rekha Jagadapillai
- Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, USA
| | - Evelyne Gozal
- Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, USA
| | - Gregory Barnes
- Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY, USA.
- Department of Neurology, University of Louisville School of Medicine, Louisville, KY, USA.
- Pediatric Research Institute, University of Louisville Autism Center, 1405 East Burnett Ave, Louisville, KY, 40217, USA.
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Wang B, Li HH, Yue XJ, Jia FY, DU L. [A review on the role of γ-aminobutyric acid signaling pathway in autism spectrum disorder]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2018; 20:974-978. [PMID: 30477634 PMCID: PMC7389027 DOI: 10.7499/j.issn.1008-8830.2018.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 09/28/2018] [Indexed: 06/09/2023]
Abstract
The etiology and pathogenesis of autism spectrum disorder (ASD) are not yet clear. Studies have shown that there are many neurotransmitter abnormalities in children with ASD, mainly involving in glutamate, γ-aminobutyric acid (GABA), dopamine, 5-HT and oxytocin. The imbalance of excitatory glutamatergic neurotransmitters and inhibitory GABAergic neurotransmitters is closely related to the pathogenesis of ASD. Both animal model studies and clinical studies on ASD suggest that GABA signaling pathway may play an important role in the pathogenesis of ASD. This article reviews the research on the association between GABA signaling pathway and the pathogenesis of ASD to further explore the pathogenesis of ASD and provide theoretical basis for the treatment of ASD.
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Affiliation(s)
- Bing Wang
- Department of Developmental and Behaviorial Pediatrics, First Hospital of Jilin University, Changchun 130021, China.
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Wang X, Kery R, Xiong Q. Synaptopathology in autism spectrum disorders: Complex effects of synaptic genes on neural circuits. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:398-415. [PMID: 28986278 DOI: 10.1016/j.pnpbp.2017.09.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 09/05/2017] [Accepted: 09/26/2017] [Indexed: 01/03/2023]
Affiliation(s)
- Xinxing Wang
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA
| | - Rachel Kery
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA; Medical Scientist Training Program (MSTP), Stony Brook University, Stony Brook, NY 11794, USA
| | - Qiaojie Xiong
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA.
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15
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Zhubi A, Chen Y, Guidotti A, Grayson DR. Epigenetic regulation of RELN and GAD1 in the frontal cortex (FC) of autism spectrum disorder (ASD) subjects. Int J Dev Neurosci 2017; 62:63-72. [PMID: 28229923 PMCID: PMC5575980 DOI: 10.1016/j.ijdevneu.2017.02.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 01/01/2023] Open
Abstract
Both Reelin (RELN) and glutamate decarboxylase 67 (GAD1) have been implicated in the pathophysiology of Autism Spectrum Disorders (ASD). We have previously shown that both mRNAs are reduced in the cerebella (CB) of ASD subjects through a mechanism that involves increases in the amounts of MECP2 binding to the corresponding promoters. In the current study, we examined the expression of RELN, GAD1, GAD2, and several other mRNAs implicated in this disorder in the frontal cortices (FC) of ASD and CON subjects. We also focused on the role that epigenetic processes play in the regulation of these genes in ASD brain. Our goal is to better understand the molecular basis for the down-regulation of genes expressed in GABAergic neurons in ASD brains. We measured mRNA levels corresponding to selected GABAergic genes using qRT-PCR in RNA isolated from both ASD and CON groups. We determined the extent of binding of MECP2 and DNMT1 repressor proteins by chromatin immunoprecipitation (ChIP) assays. The amount of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) present in the promoters of the target genes was quantified by methyl DNA immunoprecipitation (MeDIP) and hydroxyl MeDIP (hMeDIP). We detected significant reductions in the mRNAs associated with RELN and GAD1 and significant increases in mRNAs encoding the Ten-eleven Translocation (TET) enzymes 1, 2, and 3. We also detected increased MECP2 and DNMT1 binding to the corresponding promoter regions of GAD1, RELN, and GAD2. Interestingly, there were decreased amounts of 5mC at both promoters and little change in 5hmC content in these same DNA fragments. Our data demonstrate that RELN, GAD1, and several other genes selectively expressed in GABAergic neurons, are down-regulated in post-mortem ASD FC. In addition, we observed increased DNMT1 and MECP2 binding at the corresponding promoters of these genes. The finding of increased MECP2 binding to the RELN, GAD1 and GAD2 promoters, with reduced amounts of 5mC and unchanged amounts of 5hmC present in these regions, suggests the possibility that DNMT1 interacts with and alters MECP2 binding properties to selected promoters. Comparisons between data obtained from the FC with CB studies showed some common themes between brain regions which are discussed.
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Affiliation(s)
- Adrian Zhubi
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
| | - Ying Chen
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
| | - Alessandro Guidotti
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
| | - Dennis R Grayson
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
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Richard AE, Scheffer IE, Wilson SJ. Features of the broader autism phenotype in people with epilepsy support shared mechanisms between epilepsy and autism spectrum disorder. Neurosci Biobehav Rev 2017; 75:203-233. [DOI: 10.1016/j.neubiorev.2016.12.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 12/15/2016] [Accepted: 12/20/2016] [Indexed: 12/29/2022]
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Fatemi SH, Folsom TD, Liesch SB, Kneeland RE, Karkhane Yousefi M, Thuras PD. The effects of prenatal H1N1 infection at E16 on FMRP, glutamate, GABA, and reelin signaling systems in developing murine cerebellum. J Neurosci Res 2016; 95:1110-1122. [PMID: 27735078 DOI: 10.1002/jnr.23949] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 12/28/2022]
Abstract
Prenatal viral infection has been identified as a potential risk factor for the development of neurodevelopmental disorders such as schizophrenia and autism. Additionally, dysfunction in gamma-aminobutyric acid, Reelin, and fragile X mental retardation protein (FMRP)-metabotropic glutamate receptor 5 signaling systems has also been demonstrated in these two disorders. In the current report, we have characterized the developmental profiles of selected markers for these systems in cerebella of mice born to pregnant mice infected with human influenza (H1N1) virus on embryonic day 16 or sham-infected controls using SDS-PAGE and Western blotting techniques and evaluated the presence of abnormalities in the above-mentioned markers during brain development. The cerebellum was selected in light of emerging evidence that it plays roles in learning, memory, and emotional processing-all of which are disrupted in autism and schizophrenia. We identified unique patterns of gene and protein expression at birth (postnatal day 0 [P0]), childhood (P14), adolescence (P35), and young adulthood (P56) in both exposed and control mouse progeny. We also identified significant differences in protein expression for FMRP, very-low-density lipoprotein receptor, and glutamic acid decarboxylase 65 and 67 kDa proteins at specific postnatal time points in cerebella of the offspring of exposed mice. Our results provide evidence of disrupted FMRP, glutamatergic, and Reelin signaling in the exposed mouse offspring that explains the multiple brain abnormalities observed in this animal model. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- S Hossein Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, Minnesota.,Department of Neuroscience, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Timothy D Folsom
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Stephanie B Liesch
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Rachel E Kneeland
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Mahtab Karkhane Yousefi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, Minnesota.,Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, Michigan
| | - Paul D Thuras
- VA Medical Center, Department of Psychiatry, Minneapolis, Minnesota
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Brondino N, Fusar-Poli L, Panisi C, Damiani S, Barale F, Politi P. Pharmacological Modulation of GABA Function in Autism Spectrum Disorders: A Systematic Review of Human Studies. J Autism Dev Disord 2016; 46:825-39. [PMID: 26443675 DOI: 10.1007/s10803-015-2619-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Autism spectrum disorders are an emerging health problem worldwide, but little is known about their pathogenesis. It has been hypothesized that autism may result from an imbalance between excitatory glutamatergic and inhibitory GABAergic pathways. Commonly used medications such as valproate, acamprosate, and arbaclofen may act on the GABAergic system and be a potential treatment for people with ASD. The present systematic review aimed at evaluating the state-of-the-art of clinical trials of GABA modulators in autism. To date there is insufficient evidence to suggest the use of these drugs in autistic subjects, even if data are promising. Of note, short-term use of all the reviewed medications appears to be safe. Future well designed trials are needed to elucidate these preliminary findings.
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Affiliation(s)
- Natascia Brondino
- Department of Brain and Behavioral Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy.
| | - Laura Fusar-Poli
- Department of Brain and Behavioral Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy
| | - Cristina Panisi
- Department of Brain and Behavioral Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy
| | - Stefano Damiani
- Department of Brain and Behavioral Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy
| | - Francesco Barale
- Department of Brain and Behavioral Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy
| | - Pierluigi Politi
- Department of Brain and Behavioral Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy
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19
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Minshawi NF, Hurwitz S, Morriss D, McDougle CJ. Multidisciplinary assessment and treatment of self-injurious behavior in autism spectrum disorder and intellectual disability: integration of psychological and biological theory and approach. J Autism Dev Disord 2015; 45:1541-68. [PMID: 25395094 DOI: 10.1007/s10803-014-2307-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The objective of this review is to consider the psychological (largely behavioral) and biological [neurochemical, medical (including genetic), and pharmacological] theories and approaches that contribute to current thinking about the etiology and treatment of self-injurious behavior (SIB) in individuals with autism spectrum disorder and/or intellectual disability. Algorithms for the assessment and treatment of SIB in this context, respectively, from a multidisciplinary, integrative perspective are proposed and challenges and opportunities that exist in clinical and research settings are discussed.
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Affiliation(s)
- Noha F Minshawi
- Christian Sarkine Autism Treatment Center, James Whitcomb Riley Hospital for Children, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Ultrastructural analyses in the hippocampus CA1 field in Shank3-deficient mice. Mol Autism 2015; 6:41. [PMID: 26137200 PMCID: PMC4486760 DOI: 10.1186/s13229-015-0036-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 06/22/2015] [Indexed: 11/10/2022] Open
Abstract
Background The genetics of autism spectrum disorder (hereafter referred to as “autism”) are rapidly unfolding, with a significant increase in the identification of genes implicated in the disorder. Many of these genes are part of a complex landscape of genetic variants that are thought to act together to cause the behavioral phenotype associated with autism. One of the few single-locus causes of autism involves a mutation in the SH3 and multiple ankyrin repeat domains 3 (SHANK3) gene. Previous electrophysiological studies in mice with Shank3 mutations demonstrated impairment in synaptic long-term potentiation, suggesting a potential disruption at the synapse. Methods To understand how variants in SHANK3 would lead to such impairments and manifest in the brain of patients with autism, we assessed the presence of synaptic pathology in Shank3-deficient mice at 5 weeks and 3 months of age, focusing on the stratum radiatum of the CA1 field. This study analyzed both Shank3 heterozygous and homozygous mice using an electron microscopy approach to determine whether there is a morphological correlate to the synaptic functional impairment. Results As both synaptic strength and plasticity are affected in Shank3-deficient mice, we hypothesized that there would be a reduction in synapse density, postsynaptic density length, and perforated synapse density. No differences were found in most parameters assessed. However, Shank3 heterozygotes had significantly higher numbers of perforated synapses at 5 weeks compared to 3 months of age and significantly higher numbers of perforated synapses compared to 5-week-old wildtype and Shank3 homozygous mice. Conclusions Although this finding represents preliminary evidence for ultrastructural alterations, it suggests that while major structural changes seem to be compensated for in Shank3-deficient mice, more subtle morphological alterations, affecting synaptic structure, may take place in an age-dependent manner.
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El-Ansary A, Al-Ayadhi L. GABAergic/glutamatergic imbalance relative to excessive neuroinflammation in autism spectrum disorders. J Neuroinflammation 2014; 11:189. [PMID: 25407263 PMCID: PMC4243332 DOI: 10.1186/s12974-014-0189-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 10/27/2014] [Indexed: 11/10/2022] Open
Abstract
Background Autism spectrum disorder (ASD) is characterized by three core behavioral domains: social deficits, impaired communication, and repetitive behaviors. Glutamatergic/GABAergic imbalance has been found in various preclinical models of ASD. Additionally, autoimmunity immune dysfunction, and neuroinflammation are also considered as etiological mechanisms of this disorder. This study aimed to elucidate the relationship between glutamatergic/ GABAergic imbalance and neuroinflammation as two recently-discovered autism-related etiological mechanisms. Methods Twenty autistic patients aged 3 to 15 years and 19 age- and gender-matched healthy controls were included in this study. The plasma levels of glutamate, GABA and glutamate/GABA ratio as markers of excitotoxicity together with TNF-α, IL-6, IFN-γ and IFI16 as markers of neuroinflammation were determined in both groups. Results Autistic patients exhibited glutamate excitotoxicity based on a much higher glutamate concentration in the autistic patients than in the control subjects. Unexpectedly higher GABA and lower glutamate/GABA levels were recorded in autistic patients compared to control subjects. TNF-α and IL-6 were significantly lower, whereas IFN-γ and IFI16 were remarkably higher in the autistic patients than in the control subjects. Conclusion Multiple regression analysis revealed associations between reduced GABA level, neuroinflammation and glutamate excitotoxicity. This study indicates that autism is a developmental synaptic disorder showing imbalance in GABAergic and glutamatergic synapses as a consequence of neuroinflammation.
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Affiliation(s)
- Afaf El-Ansary
- Biochemistry Department, Science College, King Saud University, PO box 22452, 11495, Riyadh, Saudi Arabia. .,Autism Research and Treatment Center, Riyadh, Saudi Arabia. .,Shaik Al-Amodi Autism Research Chair, King Saud University, Riyadh, Saudi Arabia. .,Medicinal Chemistry Department, National Research Center, Dokki, Cairo, Egypt.
| | - Laila Al-Ayadhi
- Autism Research and Treatment Center, Riyadh, Saudi Arabia. .,Shaik Al-Amodi Autism Research Chair, King Saud University, Riyadh, Saudi Arabia. .,Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia.
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22
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Fatemi SH, Reutiman TJ, Folsom TD, Rustan OG, Rooney RJ, Thuras PD. Downregulation of GABAA receptor protein subunits α6, β2, δ, ε, γ2, θ, and ρ2 in superior frontal cortex of subjects with autism. J Autism Dev Disord 2014; 44:1833-45. [PMID: 24668190 DOI: 10.1007/s10803-014-2078-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We measured protein and mRNA levels for nine gamma-aminobutyric acid A (GABAA) receptor subunits in three brain regions (cerebellum, superior frontal cortex, and parietal cortex) in subjects with autism versus matched controls. We observed changes in mRNA for a number of GABAA and GABAB subunits and overall reduced protein expression for GABAA receptor alpha 6 (GABRα6), GABAA receptor beta 2 (GABRβ2), GABAA receptor delta (GABRδ), GABAA receptor epsilon (GABRε), GABAA receptor gamma 2 (GABRγ2), GABAA receptor theta (GABRθ), and GABAA receptor rho 2 (GABRρ2) in superior frontal cortex from subjects with autism. Our data demonstrate systematic changes in GABAA&B subunit expression in brains of subjects with autism, which may help explain the presence of cognitive abnormalities in subjects with autism.
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Affiliation(s)
- S Hossein Fatemi
- Division of Neuroscience Research, Department of Psychiatry, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN, 55455, USA,
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23
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Deidda G, Bozarth IF, Cancedda L. Modulation of GABAergic transmission in development and neurodevelopmental disorders: investigating physiology and pathology to gain therapeutic perspectives. Front Cell Neurosci 2014; 8:119. [PMID: 24904277 PMCID: PMC4033255 DOI: 10.3389/fncel.2014.00119] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/14/2014] [Indexed: 01/30/2023] Open
Abstract
During mammalian ontogenesis, the neurotransmitter GABA is a fundamental regulator of neuronal networks. In neuronal development, GABAergic signaling regulates neural proliferation, migration, differentiation, and neuronal-network wiring. In the adult, GABA orchestrates the activity of different neuronal cell-types largely interconnected, by powerfully modulating synaptic activity. GABA exerts these functions by binding to chloride-permeable ionotropic GABAA receptors and metabotropic GABAB receptors. According to its functional importance during development, GABA is implicated in a number of neurodevelopmental disorders such as autism, Fragile X, Rett syndrome, Down syndrome, schizophrenia, Tourette's syndrome and neurofibromatosis. The strength and polarity of GABAergic transmission is continuously modulated during physiological, but also pathological conditions. For GABAergic transmission through GABAA receptors, strength regulation is achieved by different mechanisms such as modulation of GABAA receptors themselves, variation of intracellular chloride concentration, and alteration in GABA metabolism. In the never-ending effort to find possible treatments for GABA-related neurological diseases, of great importance would be modulating GABAergic transmission in a safe and possibly physiological way, without the dangers of either silencing network activity or causing epileptic seizures. In this review, we will discuss the different ways to modulate GABAergic transmission normally at work both during physiological and pathological conditions. Our aim is to highlight new research perspectives for therapeutic treatments that reinstate natural and physiological brain functions in neuro-pathological conditions.
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Affiliation(s)
- Gabriele Deidda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
| | - Ignacio F Bozarth
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
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Cellot G, Cherubini E. GABAergic signaling as therapeutic target for autism spectrum disorders. Front Pediatr 2014; 2:70. [PMID: 25072038 PMCID: PMC4085902 DOI: 10.3389/fped.2014.00070] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 06/23/2014] [Indexed: 11/13/2022] Open
Abstract
γ-Aminobutyric acid (GABA), the main inhibitory neurotransmitter in the adult brain, early in postnatal life exerts a depolarizing and excitatory action. This depends on accumulation of chloride inside the cell via the cation-chloride importer NKCC1, being the expression of the chloride exporter KCC2 very low at birth. The developmentally regulated expression of KCC2 results in extrusion of chloride with age and a shift of GABA from the depolarizing to the hyperpolarizing direction. The depolarizing action of GABA leads to intracellular calcium rise through voltage-dependent calcium channels and/or N-methyl-d-aspartate receptors. GABA-mediated calcium signals regulate a variety of developmental processes from cell proliferation migration, differentiation, synapse maturation, and neuronal wiring. Therefore, it is not surprising that some forms of neuro-developmental disorders such as autism spectrum disorders (ASDs) are associated with alterations of GABAergic signaling and impairment of the excitatory/inhibitory balance in selective neuronal circuits. In this review, we will discuss how changes of GABAA-mediated neurotransmission affect several forms of ASDs including the Fragile X, the Angelman, and Rett syndromes. Then, we will describe various animal models of ASDs with GABAergic dysfunctions, highlighting their behavioral deficits and the possibility to rescue them by targeting selective components of the GABAergic synapse. In particular, we will discuss how in some cases, reverting the polarity of GABA responses from the depolarizing to the hyperpolarizing direction with the diuretic bumetanide, a selective blocker of NKCC1, may have beneficial effects on ASDs, thus opening new therapeutic perspectives for the treatment of these devastating disorders.
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Affiliation(s)
- Giada Cellot
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy
| | - Enrico Cherubini
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy ; European Brain Research Institute , Rome , Italy
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Zikopoulos B, Barbas H. Altered neural connectivity in excitatory and inhibitory cortical circuits in autism. Front Hum Neurosci 2013; 7:609. [PMID: 24098278 PMCID: PMC3784686 DOI: 10.3389/fnhum.2013.00609] [Citation(s) in RCA: 195] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 09/06/2013] [Indexed: 12/12/2022] Open
Abstract
Converging evidence from diverse studies suggests that atypical brain connectivity in autism affects in distinct ways short- and long-range cortical pathways, disrupting neural communication and the balance of excitation and inhibition. This hypothesis is based mostly on functional non-invasive studies that show atypical synchronization and connectivity patterns between cortical areas in children and adults with autism. Indirect methods to study the course and integrity of major brain pathways at low resolution show changes in fractional anisotropy (FA) or diffusivity of the white matter in autism. Findings in post-mortem brains of adults with autism provide evidence of changes in the fine structure of axons below prefrontal cortices, which communicate over short- or long-range pathways with other cortices and subcortical structures. Here we focus on evidence of cellular and axon features that likely underlie the changes in short- and long-range communication in autism. We review recent findings of changes in the shape, thickness, and volume of brain areas, cytoarchitecture, neuronal morphology, cellular elements, and structural and neurochemical features of individual axons in the white matter, where pathology is evident even in gross images. We relate cellular and molecular features to imaging and genetic studies that highlight a variety of polymorphisms and epigenetic factors that primarily affect neurite growth and synapse formation and function in autism. We report preliminary findings of changes in autism in the ratio of distinct types of inhibitory neurons in prefrontal cortex, known to shape network dynamics and the balance of excitation and inhibition. Finally we present a model that synthesizes diverse findings by relating them to developmental events, with a goal to identify common processes that perturb development in autism and affect neural communication, reflected in altered patterns of attention, social interactions, and language.
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Affiliation(s)
- Basilis Zikopoulos
- Neural Systems Laboratory, Department of Health Sciences, Boston University Boston, MA, USA
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Penzes P, Buonanno A, Passafaro M, Sala C, Sweet RA. Developmental vulnerability of synapses and circuits associated with neuropsychiatric disorders. J Neurochem 2013; 126:165-82. [PMID: 23574039 PMCID: PMC3700683 DOI: 10.1111/jnc.12261] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/08/2013] [Indexed: 12/20/2022]
Abstract
Psychiatric and neurodegenerative disorders, including intellectual disability, autism spectrum disorders (ASD), schizophrenia (SZ), and Alzheimer's disease, pose an immense burden to society. Symptoms of these disorders become manifest at different stages of life: early childhood, adolescence, and late adulthood, respectively. Progress has been made in recent years toward understanding the genetic substrates, cellular mechanisms, brain circuits, and endophenotypes of these disorders. Multiple lines of evidence implicate excitatory and inhibitory synaptic circuits in the cortex and hippocampus as key cellular substrates of pathogenesis in these disorders. Excitatory/inhibitory balance--modulated largely by dopamine--critically regulates cortical network function, neural network activity (i.e. gamma oscillations) and behaviors associated with psychiatric disorders. Understanding the molecular underpinnings of synaptic pathology and neuronal network activity may thus provide essential insight into the pathogenesis of these disorders and can reveal novel drug targets to treat them. Here, we discuss recent genetic, neuropathological, and molecular studies that implicate alterations in excitatory and inhibitory synaptic circuits in the pathogenesis of psychiatric disorders across the lifespan.
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Affiliation(s)
- Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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Blatt GJ. The neuropathology of autism. SCIENTIFICA 2012; 2012:703675. [PMID: 24278731 PMCID: PMC3820437 DOI: 10.6064/2012/703675] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/07/2012] [Indexed: 06/02/2023]
Abstract
Autism is a behaviorally defined neurodevelopmental disorder that affects over 1% of new births in the United States and about 2% of boys. The etiologies are unknown and they are genetically complex. There may be epigenetic effects, environmental influences, and other factors that contribute to the mechanisms and affected neural pathway(s). The underlying neuropathology of the disorder has been evolving in the literature to include specific brain areas in the cerebellum, limbic system, and cortex. Part(s) of structures appear to be affected most rather than the entire structure, for example, select nuclei of the amygdala, the fusiform face area, and so forth. Altered cortical organization characterized by more frequent and narrower minicolumns and early overgrowth of the frontal portion of the brain, affects connectivity. Abnormalities include cytoarchitectonic laminar differences, excess white matter neurons, decreased numbers of GABAergic cerebellar Purkinje cells, and other events that can be traced developmentally and cause anomalies in circuitry. Problems with neurotransmission are evident by recent receptor and binding site studies especially in the inhibitory GABA system likely contributing to an imbalance of excitatory/inhibitory transmission. As postmortem findings are related to core behavior symptoms, and technology improves, researchers are gaining a much better perspective of contributing factors to the disorder.
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Affiliation(s)
- Gene J. Blatt
- Department of Anatomy & Neurobiology, School of Medicine, Boston University, 72 East Concord Street L 1004, Boston, MA 02118, USA
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Enticott PG, Kennedy HA, Rinehart NJ, Tonge BJ, Bradshaw JL, Fitzgerald PB. GABAergic activity in autism spectrum disorders: an investigation of cortical inhibition via transcranial magnetic stimulation. Neuropharmacology 2012; 68:202-9. [PMID: 22727823 DOI: 10.1016/j.neuropharm.2012.06.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 05/11/2012] [Accepted: 06/11/2012] [Indexed: 10/28/2022]
Abstract
Mounting evidence suggests a possible role for γ-aminobutyric acid (GABA) in the neuropathophysiology of autism spectrum disorders (ASD), but the extent of this impairment is unclear. A non-invasive, in vivo measure of GABA involves transcranial magnetic stimulation (TMS) of the primary motor cortex to probe cortical inhibition. Individuals diagnosed with ASD (high-functioning autism or Asperger's disorder) (n = 36 [28 male]; mean age: 26.00 years) and a group of healthy individuals (n = 34 [23 male]; mean age: 26.21 years) (matched for age, gender, and cognitive function) were administered motor cortical TMS paradigms putatively measuring activity at GABAA and GABAB receptors (i.e., short and long interval paired pulse TMS, cortical silent period). All cortical inhibition paradigms yielded no difference between ASD and control groups. There was, however, evidence for short interval cortical inhibition (SICI) deficits among those ASD participants who had experienced early language delay, suggesting that GABA may be implicated in an ASD subtype. The current findings do not support a broad role for GABA in the neuropathophysiology of ASD, but provide further indication that GABAA could be involved in ASD where there is a delay in language acquisition. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Peter G Enticott
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, St. Kilda Road, Melbourne, Victoria 3004, Australia.
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Altered White Matter Structure of the Dentatorubrothalamic Pathway in Children with Autistic Spectrum Disorders. THE CEREBELLUM 2012; 11:957-71. [PMID: 22477362 DOI: 10.1007/s12311-012-0369-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Chattopadhyaya B, Cristo GD. GABAergic circuit dysfunctions in neurodevelopmental disorders. Front Psychiatry 2012; 3:51. [PMID: 22666213 PMCID: PMC3364508 DOI: 10.3389/fpsyt.2012.00051] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 05/08/2012] [Indexed: 01/16/2023] Open
Abstract
GABAergic interneurons control neuronal excitability, integration, and plasticity. Further, they regulate the generation of temporal synchrony and oscillatory behavior among networks of pyramidal neurons. Such oscillations within and across neural systems are believed to serve various complex functions, such as perception, movement initiation, and memory. Alterations in the development of GABAergic circuits have been implicated in various brain diseases with neurodevelopmental origin. Here, we highlight recent studies suggesting a role for alterations of GABA transmission in the pathophysiology of two neurodevelopmental diseases, schizophrenia, and autism. We further discuss how manipulations of GABA signaling may be used for novel therapeutic interventions.
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Blatt GJ, Fatemi SH. Alterations in GABAergic biomarkers in the autism brain: research findings and clinical implications. Anat Rec (Hoboken) 2011; 294:1646-52. [PMID: 21901839 DOI: 10.1002/ar.21252] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 07/27/2010] [Indexed: 11/08/2022]
Abstract
Autism is a pervasive developmental disorder characterized by repetitive stereotyped behavior, social-emotional deficits, and delayed or absent language abilities. There are known neuropathologies in the autism brain affecting limbic, cerebellar, and cortical structures but the neurochemical profile of affected individuals, revealed in postmortem tissue studies, is only recently emerging. One major component that appears highly impacted in autism is the GABAergic system. It is now apparent that there are widespread significant effects in many distributed regions in the autism brain revealed by histochemical, autoradiographic, and biochemical studies. The key synthesizing enzymes for GABA, glutamic acid decarboxylase type 65 and 67 (GAD65 and GAD67), are decreased in the cerebellum and closer examination of mRNA levels revealed that it is largely due to decreases in Purkinje cells and a subpopulation of larger dentate neurons as measured by in situ hybridization studies. Other cell types had either normal GAD levels (Golgi cells, smaller dentate interneurons, and stellate cells) or increased levels (basket cells). GABA receptor density, number, and protein expression are all decreased in the cerebellum and in select cortical areas. GABA(A) and GABA(B) subunit protein expression was significantly reduced in cerebellum, BA 9 and BA 40. Benzodiazepine binding sites were significantly reduced in the hippocampus and anterior cingulate cortex (BA 24). Taken together, data from these studies suggest that there is a marked dysregulation of the inhibitory GABA system in the autism brain affecting particular biomarkers localized to specific cell types and lamina likely influencing circuitry and behavior.
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Affiliation(s)
- Gene J Blatt
- Department of Anatomy and Neurobiology, Laboratory for Autism Neuroscience Research, Boston University School of Medicine, Massachusetts, USA.
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Non-invasive evaluation of the GABAergic/glutamatergic system in autistic patients observed by MEGA-editing proton MR spectroscopy using a clinical 3 tesla instrument. J Autism Dev Disord 2011; 41:447-54. [PMID: 20652388 DOI: 10.1007/s10803-010-1065-0] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Amino acids related to neurotransmitters and the GABAergic/glutamatergic system were measured using a 3 T-MRI instrument in 12 patients with autism and 10 normal controls. All measurements were performed in the frontal lobe (FL) and lenticular nuclei (LN) using a conventional sequence for n-acetyl aspartate (NAA) and glutamate (Glu), and the MEGA-editing method for GABA. The GABA level and [GABA]/[NAA] ratio were significantly lower (p < 0.01) in the FL, but not the LN, in patients with autism compared to normal controls. The [GABA]/[Glu] ratio in the FL was also significantly lower (p < 0.05) in the patients than in the normal controls, thus suggesting a possible abnormality in the regulation between GABA and Glu.
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LeBlanc JJ, Fagiolini M. Autism: a "critical period" disorder? Neural Plast 2011; 2011:921680. [PMID: 21826280 PMCID: PMC3150222 DOI: 10.1155/2011/921680] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Accepted: 06/02/2011] [Indexed: 11/24/2022] Open
Abstract
Cortical circuits in the brain are refined by experience during critical periods early in postnatal life. Critical periods are regulated by the balance of excitatory and inhibitory (E/I) neurotransmission in the brain during development. There is now increasing evidence of E/I imbalance in autism, a complex genetic neurodevelopmental disorder diagnosed by abnormal socialization, impaired communication, and repetitive behaviors or restricted interests. The underlying cause is still largely unknown and there is no fully effective treatment or cure. We propose that alteration of the expression and/or timing of critical period circuit refinement in primary sensory brain areas may significantly contribute to autistic phenotypes, including cognitive and behavioral impairments. Dissection of the cellular and molecular mechanisms governing well-established critical periods represents a powerful tool to identify new potential therapeutic targets to restore normal plasticity and function in affected neuronal circuits.
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Affiliation(s)
- Jocelyn J. LeBlanc
- Harvard Medical School and The F. M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, MA 02115, USA
| | - Michela Fagiolini
- Harvard Medical School and The F. M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, MA 02115, USA
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Alterations of GABAergic signaling in autism spectrum disorders. Neural Plast 2011; 2011:297153. [PMID: 21766041 PMCID: PMC3134996 DOI: 10.1155/2011/297153] [Citation(s) in RCA: 204] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Accepted: 04/01/2011] [Indexed: 11/18/2022] Open
Abstract
Autism spectrum disorders (ASDs) comprise a heterogeneous group of pathological conditions, mainly of genetic origin, characterized by stereotyped behavior, marked impairment in verbal and nonverbal communication, social skills, and cognition. Interestingly, in a small number of cases, ASDs are associated with single mutations in genes encoding for neuroligin-neurexin families. These are adhesion molecules which, by regulating transsynaptic signaling, contribute to maintain a proper excitatory/inhibitory (E/I) balance at the network level. Furthermore, GABA, the main inhibitory neurotransmitter in adult life, at late embryonic/early postnatal stages has been shown to depolarize and excite targeted cell through an outwardly directed flux of chloride. The depolarizing action of GABA and associated calcium influx regulate a variety of developmental processes from cell migration and differentiation to synapse formation. Here, we summarize recent data concerning the functional role of GABA in building up and refining neuronal circuits early in development and the molecular mechanisms regulating the E/I balance. A dysfunction of the GABAergic signaling early in development leads to a severe E/I unbalance in neuronal circuits, a condition that may account for some of the behavioral deficits observed in ASD patients.
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Matsuda Y, Inoue Y, Izumi H, Kaga M, Inagaki M, Goto YI. Fewer GABAergic interneurons, heightened anxiety and decreased high-frequency electroencephalogram components in Bronx waltzer mice, a model of hereditary deafness. Brain Res 2010; 1373:202-10. [PMID: 21146505 DOI: 10.1016/j.brainres.2010.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 11/16/2022]
Abstract
The homozygous Bronx waltzer mutation (bv/bv) results in the degeneration of most but not all of the primary auditory receptors, the inner hair cells and their afferent neurons, and leads to perceptive deafness. However, the influence of the mutation on the central nervous system (CNS) remains largely unclear. In this study, we have conducted behavioral, morphological and electrophysiological investigations to clarify the CNS dysfunction in bv/bv mice. These mutant mice exhibited heightened levels of anxiety with normal levels of motor activity. Immunohistochemical analysis revealed a significant reduction in parvalbumin-containing GABAergic interneurons in the anterior cingulate, somatosensory and auditory cortices of bv/bv mice. The current results suggest that interneuron development may be disrupted in the bv/bv cerebrum. Moreover, the high-frequency electroencephalogram components of the cortical activity, including the frequency range containing high gamma, were markedly decreased in bv/bv mice compared with controls, probably indicating a disturbance in cortical inhibitory function. Together, these results suggest that the cortical development of interneurons and their electrophysiological profiles are altered in bv/bv mice. We propose that these novel phenotypes identified in bv/bv mice provide new perspectives on the basic neuronal mechanisms of developmental disorders.
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Affiliation(s)
- Yoshiki Matsuda
- Department of Developmental Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawa Higashi, Kodaira, Tokyo 187-8553, Japan
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Oblak AL, Gibbs TT, Blatt GJ. Reduced GABAA receptors and benzodiazepine binding sites in the posterior cingulate cortex and fusiform gyrus in autism. Brain Res 2010; 1380:218-28. [PMID: 20858465 DOI: 10.1016/j.brainres.2010.09.021] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 08/24/2010] [Accepted: 09/05/2010] [Indexed: 10/19/2022]
Abstract
Individuals with autism display deficits in the social domain including the proper recognition of faces and interpretations of facial expressions. There is an extensive network of brain regions involved in face processing including the fusiform gyrus (FFG) and posterior cingulate cortex (PCC). Functional imaging studies have found that controls have increased activity in the PCC and FFG during face recognition tasks, and the FFG has differential responsiveness in autism when viewing faces. Multiple lines of evidence have suggested that the GABAergic system is disrupted in the brains of individuals with autism and it is likely that altered inhibition within the network influences the ability to perceive emotional expressions. On-the-slide ligand binding autoradiography was used to determine if there were alterations in GABA(A) and/or benzodiazepine binding sites in the brain in autism. Using (3)H-muscimol and (3)H-flunitrazepam we could determine whether the number (B(max)), binding affinity (K(d)), and/or distribution of GABA(A) receptors and benzodiazepine binding sites (BZD) differed from controls in the FFG and PCC. Significant reductions were found in the number of GABA(A) receptors and BZD binding sites in the superficial layers of the PCC and FFG, and in the number of BZD binding sites in the deep layers of the FFG. In addition, the autism group had a higher binding affinity in the superficial layers of the GABA(A) study. Taken together, these findings suggest that the disruption in inhibitory control in the cortex may contribute to the core disturbances of socio-emotional behaviors in autism.
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Affiliation(s)
- Adrian L Oblak
- Boston University School of Medicine, Department of Anatomy and Neurobiology, Boston, MA 02118, USA.
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Abstract
Autism is a behaviorally defined neurodevelopmental disorder and among its symptoms are disturbances in face and emotional processing. Emerging evidence demonstrates abnormalities in the GABAergic (gamma-aminobutyric acid) system in autism, which likely contributes to these deficits. GABA(B) receptors play an important role in modulating synapses and maintaining the balance of excitation-inhibition in the brain. The density of GABA(B) receptors in subjects with autism and matched controls was quantified in the anterior and posterior cingulate cortex, important for socio-emotional and cognitive processing, and the fusiform gyrus, important for identification of faces and facial expressions. Significant reductions in GABA(B) receptor density were demonstrated in all three regions examined suggesting that alterations in this key inhibitory receptor subtype may contribute to the functional deficits in individuals with autism. Interestingly, the presence of seizure in a subset of autism cases did not have a significant effect on the density of GABA(B) receptors in any of the three regions.
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Affiliation(s)
- Adrian L Oblak
- Department of Anatomy and Neurobiology, Laboratory of Autism Neuroscience Research, Boston University School of Medicine, Boston, MA 02118, USA.
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Lawrence YA, Kemper TL, Bauman ML, Blatt GJ. Parvalbumin-, calbindin-, and calretinin-immunoreactive hippocampal interneuron density in autism. Acta Neurol Scand 2010; 121:99-108. [PMID: 19719810 DOI: 10.1111/j.1600-0404.2009.01234.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND There has been a long-standing interest in the possible role of the hippocampus in autism and both postmortem brain and neuroimaging studies have documented varying abnormalities in this limbic system structure. AIMS This study investigates the density of subsets of hippocampal interneurons, immunostained with the calcium binding proteins, calbindin (CB), calretinin (CR) and parvalbumin (PV) to determine whether specific subpopulations of interneurons are impacted in autism. MATERIALS AND METHODS Unbiased stereological techniques were used to quantify the neuronal density of these immunoreactive subpopulations of gamma-aminobutyric acid-ergic (GABAergic) interneurons analyzed in the CA and subicular fields in postmortem brain material obtained from five autistic and five age-, gender- and postmortem interval-matched control cases. RESULTS Results indicate a selective increase in the density of CB-immunoreactive interneurons in the dentate gyrus, an increase in CR-immunoreactive interneurons in area CA1, and an increase in PV-immunoreactive interneurons in areas CA1 and CA3 in the hippocampus of individuals with autism when compared with controls. DISCUSSION/CONCLUSIONS Although our sample size is small, these findings suggest that GABAergic interneurons may represent a vulnerable target in the brains of individuals with autism, potentially impacting upon their key role in learning and information processing. These preliminary findings further suggest the need for future more expanded studies in a larger number of postmortem brain samples from cases of autism and controls.
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Affiliation(s)
- Y A Lawrence
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA.
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Oblak A, Gibbs TT, Blatt GJ. Decreased GABAA receptors and benzodiazepine binding sites in the anterior cingulate cortex in autism. Autism Res 2009; 2:205-19. [PMID: 19650112 DOI: 10.1002/aur.88] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The anterior cingulate cortex (ACC; BA 24) via its extensive limbic and high order association cortical connectivity to prefrontal cortex is a key part of an important circuitry participating in executive function, affect, and socio-emotional behavior. Multiple lines of evidence, including genetic and imaging studies, suggest that the ACC and gamma-amino-butyric acid (GABA) system may be affected in autism. The benzodiazepine binding site on the GABA(A) receptor complex is an important target for pharmacotherapy and has important clinical implications. The present multiple-concentration ligand-binding study utilized (3)H-muscimol and (3)H-flunitrazepam to determine the number (B(max)), binding affinity (K(d)), and distribution of GABA(A) receptors and benzodiazepine binding sites, respectively, in the ACC in adult autistic and control cases. Compared to controls, the autistic group had significant decreases in the mean density of GABA(A) receptors in the supragranular (46.8%) and infragranular (20.2%) layers of the ACC and in the density of benzodiazepine binding sites in the supragranular (28.9%) and infragranular (16.4%) lamina [corrected]. These findings suggest that in the autistic group this downregulation of both benzodiazepine sites and GABA(A) receptors in the ACC may be the result of increased GABA innervation and/or release disturbing the delicate excitation/inhibition balance of principal neurons as well as their output to key limbic cortical targets. Such disturbances likely underlie the core alterations in socio-emotional behaviors in autism.
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Affiliation(s)
- A Oblak
- Boston University School of Medicine, Anatomy and Neurobiology, Boston, Massachusetts 02118, USA.
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Whitney ER, Kemper TL, Rosene DL, Bauman ML, Blatt GJ. Density of cerebellar basket and stellate cells in autism: evidence for a late developmental loss of Purkinje cells. J Neurosci Res 2009; 87:2245-54. [PMID: 19301429 PMCID: PMC2760265 DOI: 10.1002/jnr.22056] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Alterations in the cerebellum have been described as a neuropathological feature of autism. Although numerous studies have focused on the Purkinje cell (PC), the projection neuron of the cerebellar cortex, PC function is critically dependent on their innervation by the GABAergic basket cells (BCs) and stellate cells (SCs) in the cerebellar molecular layer. The present study was designed to determine whether there are differences in the packing density of these inhibitory interneurons or whether the ratio of these interneurons to PCs differs in autistic and age-matched control brains. The GABAergic interneurons were identified by using immunohistochemistry for parvalbumin (PV) in serial sections from the posterior cerebellar lobe of six autistic and four control brains and counted using stereological principles. Prior PC counts in the same area on adjacent sections (Whitney et al., 2008) were available and were used to calculate the number of BCs and SCs per PC. In this sample of brains, no statistically significant difference was detected between the autistic and the control groups in the density of BCs or SCs (P = 0.44 and P = 0.84, respectively) or in the number of BCs or SCs per PC (P = 0.47 and P = 0.44, respectively). The preservation of BCs and SCs, in the presence of the reduced PC numbers as found in at least two, and possibly three, of these six autistic cases (Whitney et al., 2008) suggests that PCs were generated, migrated to their proper location in the PC layer, and subsequently died in the autistic cases that showed a reduction in PCs.
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Affiliation(s)
- Elizabeth R Whitney
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02218-2526, USA.
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Fatemi SH, Reutiman TJ, Folsom TD, Thuras PD. GABA(A) receptor downregulation in brains of subjects with autism. J Autism Dev Disord 2008; 39:223-30. [PMID: 18821008 DOI: 10.1007/s10803-008-0646-7] [Citation(s) in RCA: 310] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 06/27/2008] [Indexed: 11/28/2022]
Abstract
Gamma-aminobutyric acid A (GABA(A)) receptors are ligand-gated ion channels responsible for mediation of fast inhibitory action of GABA in the brain. Preliminary reports have demonstrated altered expression of GABA receptors in the brains of subjects with autism suggesting GABA/glutamate system dysregulation. We investigated the expression of four GABA(A) receptor subunits and observed significant reductions in GABRA1, GABRA2, GABRA3, and GABRB3 in parietal cortex (Brodmann's Area 40 (BA40)), while GABRA1 and GABRB3 were significantly altered in cerebellum, and GABRA1 was significantly altered in superior frontal cortex (BA9). The presence of seizure disorder did not have a significant impact on GABA(A) receptor subunit expression in the three brain areas. Our results demonstrate that GABA(A) receptors are reduced in three brain regions that have previously been implicated in the pathogenesis of autism, suggesting widespread GABAergic dysfunction in the brains of subjects with autism.
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Affiliation(s)
- S Hossein Fatemi
- Department of Psychiatry, University of Minnesota, Minneapolis, MN 55455, USA.
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Walker MA. Treatment of autism spectrum disorders: neurotransmitter signaling pathways involved in motivation and reward as therapeutic targets. Expert Opin Ther Targets 2008; 12:949-67. [PMID: 18620518 DOI: 10.1517/14728222.12.8.949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND There is a growing body of literature describing the etiology of autism spectrum disorders (ASD). Some of the targets suggested belong to neurochemical transmitter pathways implicated in the behavior and motivation reward pathway. OBJECTIVE To examine data linking potential targets to ASD and the feasibility of developing drugs targeting these pathways. While the inhibitors are mostly being developed for other indications, it is beneficial to examine them to determine the responsiveness of the targets to small-molecule modulation. METHODS A search in Medline and Scifinder for articles concerning relevant targets in the context of ASD and their relation to the reward signaling pathway. RESULTS There is evidence suggesting that behaviors controlled by these targets are related to behaviors exhibited by individuals with ASD. The targets appear to be involved in neurotransmitter pathways controlling motivation and reward, further implicating this system in ASD. Sufficient research has been conducted to identify lead compounds for discovering agents for treatment of ASD.
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Affiliation(s)
- Michael A Walker
- Bristol-Myers Squibb Co., Medicinal Chemistry, Research and Development, Wallingford, CT, USA.
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Microtransplantation of neurotransmitter receptors from postmortem autistic brains to Xenopus oocytes. Proc Natl Acad Sci U S A 2008; 105:10973-7. [PMID: 18645182 DOI: 10.1073/pnas.0804386105] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Autism is a complex disorder that arises from the pervasive action of genetic and epigenetic factors that alter synaptic connectivity of the brain. Although GABA and glutamate receptors seem to be two of those factors, very little is known about the functional properties of the autistic receptors. Autistic tissue samples stored in brain banks usually have relatively long postmortem times, and it is highly desirable to know whether neurotransmitter receptors in such tissues are still functional. Here we demonstrate that native receptors microtransplanted from autistic brains, as well as de novo mRNA-expressed receptors, are still functional and susceptible to detailed electrophysiological characterization even after long postmortem intervals. The opportunity to study the properties of human receptors present in diseased brains not only opens new avenues toward understanding autism and other neurological disorders, but it also makes the microtransplantation method a useful translational system to evaluate and develop novel medicinal drugs.
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DeLorey TM, Sahbaie P, Hashemi E, Homanics GE, Clark JD. Gabrb3 gene deficient mice exhibit impaired social and exploratory behaviors, deficits in non-selective attention and hypoplasia of cerebellar vermal lobules: a potential model of autism spectrum disorder. Behav Brain Res 2008; 187:207-20. [PMID: 17983671 PMCID: PMC2684890 DOI: 10.1016/j.bbr.2007.09.009] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 09/04/2007] [Accepted: 09/09/2007] [Indexed: 12/17/2022]
Abstract
OBJECTIVE GABA(A) receptors play an important regulatory role in the developmental events leading to the formation of complex neuronal networks and to the behaviors they govern. The primary aim of this study was to assess whether gabrb3 gene deficient (gabrb3(-/-)) mice exhibit abnormal social behavior, a core deficit associated with autism spectrum disorder. METHODS Social and exploratory behaviors along with non-selective attention were assessed in gabrb3(-/-), littermates (gabrb3(+/+)) and progenitor strains, C57BL/6J and 129/SvJ. In addition, semi-quantitative assessments of the size of cerebellar vermal lobules were performed on gabrb3(+/+) and gabrb3(-/-) mice. RESULTS Relative to controls, gabrb3(-/-) mice exhibited significant deficits in activities related to social behavior including sociability, social novelty and nesting. In addition, gabrb3(-/-) mice also exhibited differences in exploratory behavior compared to controls, as well as reductions in the frequency and duration of rearing episodes, suggested as being an index of non-selective attention. Gabrb3(-/-) mice also displayed significant hypoplasia of the cerebellar vermis compared to gabrb3(+/+) mice. CONCLUSIONS The observed behavioral deficits, especially regarding social behaviors, strengthens the face validity of the gabrb3 gene deficient mouse as being a model of autism spectrum disorder.
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Affiliation(s)
- Timothy M DeLorey
- Molecular Research Institute, 1000 Elwell Court, Suite 105, Palo Alto, CA 94303, USA.
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Mercadante MT, Cysneiros RM, Schwartzman JS, Arida RM, Cavalheiro EA, Scorza FA. Neurogenesis in the amygdala: A new etiologic hypothesis of autism? Med Hypotheses 2008; 70:352-7. [PMID: 17601677 DOI: 10.1016/j.mehy.2007.05.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2007] [Accepted: 05/09/2007] [Indexed: 11/24/2022]
Abstract
Neurogenesis studies had an increased development after BrdU (5-bromo-3'-deoxyuridine), a marker of cell proliferation. Today, several studies have showed the relevance of neurogenesis in the hippocampal formation. Notwithstanding, other brains areas have been described presenting neurogenesis, including the amygdala. This key structure is a complex cerebral region which has been associated with social behaviors and the emotional significance of the daily experiences. Several studies have associated the amygdala to the autism, a severe neurodevelopmental disorder. In this paper, we discuss the hypothesis of neurogenesis in the amygdala as a contributing cause of autism. The social skills require competent new neuronal connections, including efficient plasticity synaptic rearranging. Interestingly, emotional context cannot be imprinting in mature neurons in the presence of GABA, a neurotransmitter release during new environments experiences. However, it is known that new neurons are not well responsive to GABA stimulation, allowing the long-term potentiation necessary for the learning process. Based on these evidence it is tantalizing to hypothesize that the sociability impairment seen in some individuals with autism may partly be assigned to impaired regulation of the GABAergic system and to the impact of this impairment on the adequate functioning of the amygdala and on its capacity to store new experiences and to modulate the plasticity of the corticostriatal connections.
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Affiliation(s)
- Marcos Tomanik Mercadante
- Department of Psychiatry, Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil
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