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Wang HC, Feldman DE. Degraded tactile coding in the Cntnap2 mouse model of autism. Cell Rep 2024; 43:114612. [PMID: 39110592 PMCID: PMC11396660 DOI: 10.1016/j.celrep.2024.114612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 06/20/2024] [Accepted: 07/24/2024] [Indexed: 09/01/2024] Open
Abstract
Atypical sensory processing is common in autism, but how neural coding is disrupted in sensory cortex is unclear. We evaluate whisker touch coding in L2/3 of somatosensory cortex (S1) in Cntnap2-/- mice, which have reduced inhibition. This classically predicts excess pyramidal cell spiking, but this remains controversial, and other deficits may dominate. We find that c-fos expression is elevated in S1 of Cntnap2-/- mice under spontaneous activity conditions but is comparable to that of control mice after whisker stimulation, suggesting normal sensory-evoked spike rates. GCaMP8m imaging from L2/3 pyramidal cells shows no excess whisker responsiveness, but it does show multiple signs of degraded somatotopic coding. This includes broadened whisker-tuning curves, a blurred whisker map, and blunted whisker point representations. These disruptions are greater in noisy than in sparse sensory conditions. Tuning instability across days is also substantially elevated in Cntnap2-/-. Thus, Cntnap2-/- mice show no excess sensory-evoked activity, but a degraded and unstable tactile code in S1.
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Affiliation(s)
- Han Chin Wang
- Department of Molecular & Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniel E Feldman
- Department of Molecular & Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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2
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Fuchs C, ‘t Hoen PAC, Müller AR, Ehrhart F, Van Karnebeek CDM. Drug repurposing in Rett and Rett-like syndromes: a promising yet underrated opportunity? Front Med (Lausanne) 2024; 11:1425038. [PMID: 39135718 PMCID: PMC11317438 DOI: 10.3389/fmed.2024.1425038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/12/2024] [Indexed: 08/15/2024] Open
Abstract
Rett syndrome (RTT) and Rett-like syndromes [i.e., CDKL5 deficiency disorder (CDD) and FOXG1-syndrome] represent rare yet profoundly impactful neurodevelopmental disorders (NDDs). The severity and complexity of symptoms associated with these disorders, including cognitive impairment, motor dysfunction, seizures and other neurological features significantly affect the quality of life of patients and families. Despite ongoing research efforts to identify potential therapeutic targets and develop novel treatments, current therapeutic options remain limited. Here the potential of drug repurposing (DR) as a promising avenue for addressing the unmet medical needs of individuals with RTT and related disorders is explored. Leveraging existing drugs for new therapeutic purposes, DR presents an attractive strategy, particularly suited for neurological disorders given the complexities of the central nervous system (CNS) and the challenges in blood-brain barrier penetration. The current landscape of DR efforts in these syndromes is thoroughly examined, with partiuclar focus on shared molecular pathways and potential common drug targets across these conditions.
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Affiliation(s)
| | - Peter A. C. ‘t Hoen
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Annelieke R. Müller
- Department of Pediatrics, Emma Children’s Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam UMC Location University of Amsterdam, Amsterdam, Netherlands
- Amsterdam UMC, Emma Center for Personalized Medicine, Amsterdam, Netherlands
- Department of Human Genetics, Amsterdam Reproduction and Development, Amsterdam UMC Location University of Amsterdam, Amsterdam, Netherlands
| | - Friederike Ehrhart
- Department of Bioinformatics – BiGCaT, Research Institute of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, Netherlands
| | - Clara D. M. Van Karnebeek
- Department of Pediatrics, Emma Children’s Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam UMC Location University of Amsterdam, Amsterdam, Netherlands
- Amsterdam UMC, Emma Center for Personalized Medicine, Amsterdam, Netherlands
- Department of Human Genetics, Amsterdam Reproduction and Development, Amsterdam UMC Location University of Amsterdam, Amsterdam, Netherlands
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3
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Stroh A, Schweiger S, Ramirez JM, Tüscher O. The selfish network: how the brain preserves behavioral function through shifts in neuronal network state. Trends Neurosci 2024; 47:246-258. [PMID: 38485625 DOI: 10.1016/j.tins.2024.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 01/31/2024] [Accepted: 02/19/2024] [Indexed: 04/12/2024]
Abstract
Neuronal networks possess the ability to regulate their activity states in response to disruptions. How and when neuronal networks turn from physiological into pathological states, leading to the manifestation of neuropsychiatric disorders, remains largely unknown. Here, we propose that neuronal networks intrinsically maintain network stability even at the cost of neuronal loss. Despite the new stable state being potentially maladaptive, neural networks may not reverse back to states associated with better long-term outcomes. These maladaptive states are often associated with hyperactive neurons, marking the starting point for activity-dependent neurodegeneration. Transitions between network states may occur rapidly, and in discrete steps rather than continuously, particularly in neurodegenerative disorders. The self-stabilizing, metastable, and noncontinuous characteristics of these network states can be mathematically described as attractors. Maladaptive attractors may represent a distinct pathophysiological entity that could serve as a target for new therapies and for fostering resilience.
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Affiliation(s)
- Albrecht Stroh
- Leibniz Institute for Resilience Research, Mainz, Germany; Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Susann Schweiger
- Leibniz Institute for Resilience Research, Mainz, Germany; Institute of Human Genetics, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany; Institute of Molecular Biology (IMB), Mainz, Germany
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research at the Seattle Children's Research Institute, University of Washington, Seattle, USA
| | - Oliver Tüscher
- Leibniz Institute for Resilience Research, Mainz, Germany; Institute of Molecular Biology (IMB), Mainz, Germany; Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.
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4
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Zhang X, Smits M, Curfs L, Spruyt K. Sleep and the Social Profiles of Individuals With Rett Syndrome. Pediatr Neurol 2024; 152:153-161. [PMID: 38290182 DOI: 10.1016/j.pediatrneurol.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 12/30/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024]
Abstract
BACKGROUND This study investigates the distinctive social behaviors observed in individuals with Rett syndrome (RTT), characterized by the loss of spoken language, impaired eye gaze communication, gait abnormalities, and sleep issues. The research aims to identify social profiles in RTT and explore their correlation with sleep, sleep-disordered breathing (SDB), and daytime sleepiness. METHODS Standard overnight sleep macrostructure and respiratory parameters were assessed. Extracting 25 social-related items and one for daytime sleepiness from the Rett Syndrome Behavioral Questionnaire, factor analysis was applied to establish latent social profiles. These profiles were then correlated with sleep parameters. The nonparametric Mann-Whitney U test compared social profiles based on the presence of SDB (defined by an apnea-hypopnea index greater than one per hour) and daytime sleepiness. RESULTS The study involved 12 female subjects with confirmed RTT diagnoses and MECP2 mutations, aged 8.54 ± 5.30 years. The Rett Syndrome Behavioral Questionnaire revealed a total average score of 25.83 ± 12.34, indicating varying degrees of social impairments. Comprising 25 social-related items, factor analysis yielded four social profiles: "interactive motricity," "mood change," "anxiety/agitation," and "gazing." Longer sleep onset latency correlated with increased socio-behavioral impairments, particularly in interactive motricity reduction. Conversely, higher rapid eye movement sleep was associated with fewer interactive socio-motor behaviors. No significant differences in social profiles were found concerning the presence of SDB or daytime sleepiness. CONCLUSIONS The findings suggest four distinct social profiles in RTT individuals, hinting at shared disrupted circuits between sensorimotor functioning and sleep-related neuronal pathways. Despite the absence of differences in SDB or daytime sleepiness, the study highlights the relationship between sleep parameters, such as sleep onset latency and rapid eye movement sleep, and socio-behavioral outcomes in RTT with MECP2 mutations.
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Affiliation(s)
- Xinyan Zhang
- Université Paris Cité, NeuroDiderot - INSERM, Paris, France
| | - Marcel Smits
- Department of Sleep-Wake Disorders and Chronobiology, Hospital Gelderse Vallei Ede, Ede, Netherlands; Governor Kremers Centre, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Leopold Curfs
- Governor Kremers Centre, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Karen Spruyt
- Université Paris Cité, NeuroDiderot - INSERM, Paris, France.
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McArdle CJ, Arnone AA, Heaney CF, Raab-Graham KF. A paradoxical switch: the implications of excitatory GABAergic signaling in neurological disorders. Front Psychiatry 2024; 14:1296527. [PMID: 38268565 PMCID: PMC10805837 DOI: 10.3389/fpsyt.2023.1296527] [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: 09/18/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024] Open
Abstract
Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. In the mature brain, inhibitory GABAergic signaling is critical in maintaining neuronal homeostasis and vital human behaviors such as cognition, emotion, and motivation. While classically known to inhibit neuronal function under physiological conditions, previous research indicates a paradoxical switch from inhibitory to excitatory GABAergic signaling that is implicated in several neurological disorders. Various mechanisms have been proposed to contribute to the excitatory switch such as chloride ion dyshomeostasis, alterations in inhibitory receptor expression, and modifications in GABAergic synaptic plasticity. Of note, the hypothesized mechanisms underlying excitatory GABAergic signaling are highlighted in a number of neurodevelopmental, substance use, stress, and neurodegenerative disorders. Herein, we present an updated review discussing the presence of excitatory GABAergic signaling in various neurological disorders, and their potential contributions towards disease pathology.
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Affiliation(s)
- Colin J. McArdle
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Alana A. Arnone
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
- Department of General Surgery, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Chelcie F. Heaney
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Kimberly F. Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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Comas M, De Pietri Tonelli D, Berdondini L, Astiz M. Ontogeny of the circadian system: a multiscale process throughout development. Trends Neurosci 2024; 47:36-46. [PMID: 38071123 DOI: 10.1016/j.tins.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/02/2023] [Accepted: 11/12/2023] [Indexed: 01/12/2024]
Abstract
The 24 h (circadian) timing system develops in mammals during the perinatal period. It carries out the essential task of anticipating daily recurring environmental changes to identify the best time of day for each molecular, cellular, and systemic process. Although significant knowledge has been acquired about the organization and function of the adult circadian system, relatively little is known about its ontogeny. During the perinatal period, the circadian system progressively gains functionality under the influence of the early environment. This review explores current evidence on the development of the circadian clock in mammals, highlighting the multilevel complexity of the process and the importance of gaining a better understanding of its underlying biology.
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Affiliation(s)
- Maria Comas
- Circadian Physiology of Neurons and Glia Laboratory, Achucarro Basque Center for Neuroscience, 48940 Leioa, Basque Country, Spain
| | | | - Luca Berdondini
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Mariana Astiz
- Circadian Physiology of Neurons and Glia Laboratory, Achucarro Basque Center for Neuroscience, 48940 Leioa, Basque Country, Spain; Ikerbasque - Basque Foundation for Science, Bilbao, Spain; Institute of Neurobiology, University of Lübeck, 23562 Lübeck, Germany.
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7
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McMoneagle E, Zhou J, Zhang S, Huang W, Josiah SS, Ding K, Wang Y, Zhang J. Neuronal K +-Cl - cotransporter KCC2 as a promising drug target for epilepsy treatment. Acta Pharmacol Sin 2024; 45:1-22. [PMID: 37704745 PMCID: PMC10770335 DOI: 10.1038/s41401-023-01149-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/02/2023] [Indexed: 09/14/2023] Open
Abstract
Epilepsy is a prevalent neurological disorder characterized by unprovoked seizures. γ-Aminobutyric acid (GABA) serves as the primary fast inhibitory neurotransmitter in the brain, and GABA binding to the GABAA receptor (GABAAR) regulates Cl- and bicarbonate (HCO3-) influx or efflux through the channel pore, leading to GABAergic inhibition or excitation, respectively. The neuron-specific K+-Cl- cotransporter 2 (KCC2) is essential for maintaining a low intracellular Cl- concentration, ensuring GABAAR-mediated inhibition. Impaired KCC2 function results in GABAergic excitation associated with epileptic activity. Loss-of-function mutations and altered expression of KCC2 lead to elevated [Cl-]i and compromised synaptic inhibition, contributing to epilepsy pathogenesis in human patients. KCC2 antagonism studies demonstrate the necessity of limiting neuronal hyperexcitability within the brain, as reduced KCC2 functioning leads to seizure activity. Strategies focusing on direct (enhancing KCC2 activation) and indirect KCC2 modulation (altering KCC2 phosphorylation and transcription) have proven effective in attenuating seizure severity and exhibiting anti-convulsant properties. These findings highlight KCC2 as a promising therapeutic target for treating epilepsy. Recent advances in understanding KCC2 regulatory mechanisms, particularly via signaling pathways such as WNK, PKC, BDNF, and its receptor TrkB, have led to the discovery of novel small molecules that modulate KCC2. Inhibiting WNK kinase or utilizing newly discovered KCC2 agonists has demonstrated KCC2 activation and seizure attenuation in animal models. This review discusses the role of KCC2 in epilepsy and evaluates its potential as a drug target for epilepsy treatment by exploring various strategies to regulate KCC2 activity.
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Affiliation(s)
- Erin McMoneagle
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Jin Zhou
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Shiyao Zhang
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China
| | - Weixue Huang
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sunday Solomon Josiah
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Ke Ding
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK.
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China.
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
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8
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Dos Santos AB, Larsen SD, Guo L, Barbagallo P, Montalant A, Verhage M, Sørensen JB, Perrier JF. Microcircuit failure in STXBP1 encephalopathy leads to hyperexcitability. Cell Rep Med 2023; 4:101308. [PMID: 38086378 PMCID: PMC10772346 DOI: 10.1016/j.xcrm.2023.101308] [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: 02/17/2023] [Revised: 08/29/2023] [Accepted: 11/09/2023] [Indexed: 12/22/2023]
Abstract
De novo mutations in STXBP1 are among the most prevalent causes of neurodevelopmental disorders and lead to haploinsufficiency, cortical hyperexcitability, epilepsy, and other symptoms in people with mutations. Given that Munc18-1, the protein encoded by STXBP1, is essential for excitatory and inhibitory synaptic transmission, it is currently not understood why mutations cause hyperexcitability. We find that overall inhibition in canonical feedforward microcircuits is defective in a P15-22 mouse model for Stxbp1 haploinsufficiency. Unexpectedly, we find that inhibitory synapses formed by parvalbumin-positive interneurons were largely unaffected. Instead, excitatory synapses fail to recruit inhibitory interneurons. Modeling confirms that defects in the recruitment of inhibitory neurons cause hyperexcitation. CX516, an ampakine that enhances excitatory synapses, restores interneuron recruitment and prevents hyperexcitability. These findings establish deficits in excitatory synapses in microcircuits as a key underlying mechanism for cortical hyperexcitability in a mouse model of Stxbp1 disorder and identify compounds enhancing excitation as a direction for therapy.
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Affiliation(s)
- Altair Brito Dos Santos
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Silas Dalum Larsen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Liangchen Guo
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Paola Barbagallo
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Alexia Montalant
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Matthijs Verhage
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam and Amsterdam University Medical Center, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands; Department of Human Genetics, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam and Amsterdam University Medical Center, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Jakob Balslev Sørensen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Jean-François Perrier
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
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9
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Papadelis C, Ntolkeras G, Tokatly Latzer I, DiBacco ML, Afacan O, Warfield S, Shi X, Roullet JB, Gibson KM, Pearl PL. Reduced evoked cortical beta and gamma activity and neuronal synchronization in succinic semialdehyde dehydrogenase deficiency, a disorder of γ-aminobutyric acid metabolism. Brain Commun 2023; 5:fcad291. [PMID: 37953848 PMCID: PMC10636566 DOI: 10.1093/braincomms/fcad291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 08/22/2023] [Accepted: 10/24/2023] [Indexed: 11/14/2023] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency is a rare autosomal recessively inherited metabolic disorder of γ-aminobutyric acid catabolism manifested by intellectual disability, expressive aphasia, movement disorders, psychiatric ailments and epilepsy. Subjects with succinic semialdehyde dehydrogenase deficiency are characterized by elevated γ-aminobutyric acid and related metabolites, such as γ-guanidinobutyric acid, and an age-dependent downregulation of cerebral γ-aminobutyric acid receptors. These findings indicate impaired γ-aminobutyric acid and γ-aminobutyric acid sub-type A (GABAA) receptor signalling as major factors underlying the pathophysiology of this neurometabolic disorder. We studied the cortical oscillation patterns and their relationship with γ-aminobutyric acid metabolism in 18 children affected by this condition and 10 healthy controls. Using high-density EEG, we recorded somatosensory cortical responses and resting-state activity. Using electrical source imaging, we estimated the relative power changes (compared with baseline) in both stimulus-evoked and stimulus-induced responses for physiologically relevant frequency bands and resting-state power. Stimulus-evoked oscillations are phase locked to the stimulus, whereas induced oscillations are not. Power changes for both evoked and induced responses as well as resting-state power were correlated with plasma γ-aminobutyric acid and γ-guanidinobutyric acid concentrations and with cortical γ-aminobutyric acid measured by proton magnetic resonance spectroscopy. Plasma γ-aminobutyric acid, γ-guanidinobutyric acid and cortical γ-aminobutyric acid were higher in patients than in controls (P < 0.001 for both). Beta and gamma relative power were suppressed for evoked responses in patients versus controls (P < 0.01). No group differences were observed for induced activity (P > 0.05). The mean gamma frequency of evoked responses was lower in patients versus controls (P = 0.002). Resting-state activity was suppressed in patients for theta (P = 0.011) and gamma (P < 0.001) bands. Evoked power changes were inversely correlated with plasma γ-aminobutyric acid and with γ-guanidinobutyric acid for beta (P < 0.001) and gamma (P < 0.001) bands. Similar relationships were observed between the evoked power changes and cortical γ-aminobutyric acid for all tested areas in the beta band (P < 0.001) and for the posterior cingulate gyrus in the gamma band (P < 0.001). We also observed a negative correlation between resting-state activity and plasma γ-aminobutyric acid and γ-guanidinobutyric acid for theta (P < 0.001; P = 0.003), alpha (P = 0.003; P = 0.02) and gamma (P = 0.02; P = 0.01) bands. Our findings indicate that increased γ-aminobutyric acid concentration is associated with reduced sensory-evoked beta and gamma activity and impaired neuronal synchronization in patients with succinic semialdehyde dehydrogenase deficiency. This further elucidates the pathophysiology of this neurometabolic disorder and serves as a potential biomarker for therapeutic trials.
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Affiliation(s)
- Christos Papadelis
- Jane and John Justin Institute for Mind Health, Cook Children’s Health Care System, Fort Worth, TX 76104, USA
- School of Medicine, Texas Christian University, Fort Worth, TX 76129, USA
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Georgios Ntolkeras
- Division of Newborn Medicine, Department of Medicine, Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Itay Tokatly Latzer
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02129, USA
- Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Melissa L DiBacco
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Onur Afacan
- Department of Radiology, Computational Radiology Laboratory, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Simon Warfield
- Department of Radiology, Computational Radiology Laboratory, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Xutong Shi
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99202, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99202, USA
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99202, USA
| | - Phillip L Pearl
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02129, USA
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10
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Rupert DD, Pagliaro AH, Choe J, Shea SD. Selective Deletion of Methyl CpG Binding Protein 2 from Parvalbumin Interneurons in the Auditory Cortex Delays the Onset of Maternal Retrieval in Mice. J Neurosci 2023; 43:6745-6759. [PMID: 37625856 PMCID: PMC10552946 DOI: 10.1523/jneurosci.0838-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/05/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Mutations in MECP2 cause the neurodevelopmental disorder Rett syndrome. MECP2 codes for methyl CpG binding protein 2 (MECP2), a transcriptional regulator that activates genetic programs for experience-dependent plasticity. Many neural and behavioral symptoms of Rett syndrome may result from dysregulated timing and thresholds for plasticity. As a model of adult plasticity, we examine changes to auditory cortex inhibitory circuits in female mice when they are first exposed to pups; this plasticity facilitates behavioral responses to pups emitting distress calls. Brainwide deletion of Mecp2 alters expression of markers associated with GABAergic parvalbumin interneurons (PVins) and impairs the emergence of pup retrieval. We hypothesized that loss of Mecp2 in PVins disproportionately contributes to the phenotype. Here, we find that deletion of Mecp2 from PVins delayed the onset of maternal retrieval behavior and recapitulated the major molecular and neurophysiological features of brainwide deletion of Mecp2 We observed that when PVin-selective mutants were exposed to pups, auditory cortical expression of PVin markers increased relative to that in wild-type littermates. PVin-specific mutants also failed to show the inhibitory auditory cortex plasticity seen in wild-type mice on exposure to pups and their vocalizations. Finally, using an intersectional viral genetic strategy, we demonstrate that postdevelopmental loss of Mecp2 in PVins of the auditory cortex is sufficient to delay onset of maternal retrieval. Our results support a model in which PVins play a central role in adult cortical plasticity and may be particularly impaired by loss of Mecp2 SIGNIFICANCE STATEMENT Rett syndrome is a neurodevelopmental disorder that includes deficits in both communication and the ability to update brain connections and activity during learning (plasticity). This condition is caused by mutations in the gene MECP2 We use a maternal behavioral test in mice requiring both vocal perception and neural plasticity to probe the role of Mecp2 in social and sensory learning. Mecp2 is normally active in all brain cells, but here we remove it from a specific population (parvalbumin neurons). We find that this is sufficient to delay learned behavioral responses to pups and recreates many deficits seen in whole-brain Mecp2 deletion. Our findings suggest that parvalbumin neurons specifically are central to the consequences of loss of Mecp2 activity and yield clues as to possible mechanisms by which Rett syndrome impairs brain function.
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Affiliation(s)
- Deborah D Rupert
- Department of Neurobiology and Behavior and Medical Scientist Training Program, School of Medicine, Stony Brook University, Stony Brook, New York 11794-8434
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Alexa H Pagliaro
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Jane Choe
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Stephen D Shea
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
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11
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Wang HC, Feldman DE. Degraded tactile coding in the Cntnap2 mouse model of autism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560240. [PMID: 37808857 PMCID: PMC10557772 DOI: 10.1101/2023.09.29.560240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Atypical sensory processing in autism involves altered neural circuit function and neural coding in sensory cortex, but the nature of coding disruption is poorly understood. We characterized neural coding in L2/3 of whisker somatosensory cortex (S1) of Cntnap2-/- mice, an autism model with pronounced hypofunction of parvalbumin (PV) inhibitory circuits. We tested for both excess spiking, which is often hypothesized in autism models with reduced inhibition, and alterations in somatotopic coding, using c-fos immunostaining and 2-photon calcium imaging in awake mice. In Cntnap2-/- mice, c-fos-(+) neuron density was elevated in L2/3 of S1 under spontaneous activity conditions, but comparable to control mice after whisker stimulation, suggesting that sensory-evoked spiking was relatively normal. 2-photon GCaMP8m imaging in L2/3 pyramidal cells revealed no increase in whisker-evoked response magnitude, but instead showed multiple signs of degraded somatotopic coding. These included broadening of whisker tuning curves, blurring of the whisker map, and blunting of the point representation of each whisker. These altered properties were more pronounced in noisy than sparse sensory conditions. Tuning instability, assessed over 2-3 weeks of longitudinal imaging, was also significantly increased in Cntnap2-/- mice. Thus, Cntnap2-/- mice show no excess spiking, but a degraded and unstable tactile code in S1.
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Affiliation(s)
- Han Chin Wang
- Department of Molecular & Cell Biology, and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California 94720, USA
| | - Daniel E. Feldman
- Department of Molecular & Cell Biology, and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California 94720, USA
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12
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Yakovlev AV, Kurmashova E, Gataulina E, Gerasimova E, Khalilov I, Sitdikova GF. Maternal hyperhomocysteinemia increases seizures susceptibility of neonatal rats. Life Sci 2023; 329:121953. [PMID: 37467884 DOI: 10.1016/j.lfs.2023.121953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023]
Abstract
AIMS Neonatal seizures are severe pathologies which may result in long-term neurological consequences. High plasma concentrations of homocysteine - hyperhomocysteinemia (hHCy) - are associated with epilepsy. In the present study, we evaluated susceptibility to seizure of neonatal rats with prenatal hHCy. MAIN METHODS Prenatal hHCy was induced by feeding females with a high-methionine diet. Experiments were performed on pups during the first three postnatal weeks. Flurothyl-induced epileptic behavior was assessed according to Racine's scale. Epileptiform activity in the hippocampus was recorded using electrophysiological methods. The balance of excitation/inhibition, functional GABAergic inhibition and GABA reversal potential in hippocampal neurons were analyzed. KEY FINDINGS Rats with hHCy developed more severe stages of behavioral patterns during flurothyl-induced epilepsy with shorter latency. Electrophysiological recordings demonstrated higher background neuronal activity in rats with hHCy. Seizure-like events triggered by flurothyl (in vivo) or 4-aminopyridine (in vitro) showed shorter latency, higher power and amplitude. An increased glutamate/GABA synaptic ratio was shown in the pyramidal neurons of rats with hHCy and more slices demonstrated excitation by isoguvacine, a selective GABA(A) receptor agonist, during the first and second postnatal weeks. The GABA driving force and the reversal potential of GABA(A) currents were more positive during the second postnatal week for hHCy rats. SIGNIFICANCE The higher susceptibility to seizures in rats with prenatal hHCy due to a shift in the balance of excitation/inhibition toward excitation may underlie the clinical evidence about the association of hHCy with an increased risk of epilepsy.
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Affiliation(s)
- A V Yakovlev
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia.
| | - E Kurmashova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - E Gataulina
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - E Gerasimova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - I Khalilov
- Institut de Neurobiologie de la Méditerranée, INMED UMR901 Parc scientifique de Luminy, 163 avenue de Luminy BP13 - 13273, Marseille cedex 09, France; Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - G F Sitdikova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
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13
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Monday HR, Wang HC, Feldman DE. Circuit-level theories for sensory dysfunction in autism: convergence across mouse models. Front Neurol 2023; 14:1254297. [PMID: 37745660 PMCID: PMC10513044 DOI: 10.3389/fneur.2023.1254297] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/14/2023] [Indexed: 09/26/2023] Open
Abstract
Individuals with autism spectrum disorder (ASD) exhibit a diverse range of behavioral features and genetic backgrounds, but whether different genetic forms of autism involve convergent pathophysiology of brain function is unknown. Here, we analyze evidence for convergent deficits in neural circuit function across multiple transgenic mouse models of ASD. We focus on sensory areas of neocortex, where circuit differences may underlie atypical sensory processing, a central feature of autism. Many distinct circuit-level theories for ASD have been proposed, including increased excitation-inhibition (E-I) ratio and hyperexcitability, hypofunction of parvalbumin (PV) interneuron circuits, impaired homeostatic plasticity, degraded sensory coding, and others. We review these theories and assess the degree of convergence across ASD mouse models for each. Behaviorally, our analysis reveals that innate sensory detection behavior is heightened and sensory discrimination behavior is impaired across many ASD models. Neurophysiologically, PV hypofunction and increased E-I ratio are prevalent but only rarely generate hyperexcitability and excess spiking. Instead, sensory tuning and other aspects of neural coding are commonly degraded and may explain impaired discrimination behavior. Two distinct phenotypic clusters with opposing neural circuit signatures are evident across mouse models. Such clustering could suggest physiological subtypes of autism, which may facilitate the development of tailored therapeutic approaches.
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Affiliation(s)
- Hannah R. Monday
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | | | - Daniel E. Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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14
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Zhao M, Kwon SE. Interneuron-Targeted Disruption of SYNGAP1 Alters Sensory Representations in the Neocortex and Impairs Sensory Learning. J Neurosci 2023; 43:6212-6226. [PMID: 37558489 PMCID: PMC10476640 DOI: 10.1523/jneurosci.1997-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 08/11/2023] Open
Abstract
SYNGAP1 haploinsufficiency in humans leads to severe neurodevelopmental disorders characterized by intellectual disability, autism, epilepsy, and sensory processing deficits. However, the circuit mechanisms underlying these disorders are not well understood. In mice, a decrease of SynGAP levels results in cognitive deficits by interfering with the development of excitatory glutamatergic connections. Recent evidence suggests that SynGAP also plays a crucial role in the development and function of GABAergic inhibitory interneurons. Nevertheless, it remains uncertain whether and to what extent the expression of SYNGAP1 in inhibitory interneurons contributes to cortical circuit function and related behaviors. The activity of cortical neurons has not been measured simultaneously with behavior. To address these gaps, we recorded from layer 2/3 neurons in the primary whisker somatosensory cortex (wS1) of mice while they learned to perform a whisker tactile detection task. Our results demonstrate that mice with interneuron-specific SYNGAP1 haploinsufficiency exhibit learning deficits characterized by heightened behavioral responses in the absence of relevant sensory input and premature responses to unrelated sensory stimuli not associated with reward acquisition. These behavioral deficits are accompanied by specific circuit abnormalities within wS1. Interneuron-specific SYNGAP1 haploinsufficiency increases detrimental neuronal correlations directly related to task performance and enhances responses to irrelevant sensory stimuli unrelated to the reward acquisition. In summary, our findings indicate that a reduction of SynGAP in inhibitory interneurons impairs sensory representation in the primary sensory cortex by disrupting neuronal correlations, which likely contributes to the observed cognitive deficits in mice with pan-neuronal SYNGAP1 haploinsufficiency.SIGNIFICANCE STATEMENT SYNGAP1 haploinsufficiency leads to severe neurodevelopmental disorders. The exact nature of neural circuit dysfunction caused by SYNGAP1 haploinsufficiency remains poorly understood. SynGAP plays a critical role in the function of GABAergic inhibitory interneurons as well as glutamatergic pyramidal neurons in the neocortex. Whether and how decreasing SYNGAP1 level in inhibitory interneurons disrupts a behaviorally relevant circuit remains unclear. We measure neural activity and behavior in mice learning a perceptual task. Mice with interneuron-targeted disruption of SYNGAP1 display increased detrimental neuronal correlations and elevated responses to irrelevant sensory inputs, which are related to impaired task performance. These results show that cortical interneuron dysfunction contributes to sensory deficits in SYNGAP1 haploinsufficiency with important implications for identifying therapeutic targets.
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Affiliation(s)
- Meiling Zhao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Sung Eun Kwon
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
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15
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Valenti D, Vacca RA. Brain Mitochondrial Bioenergetics in Genetic Neurodevelopmental Disorders: Focus on Down, Rett and Fragile X Syndromes. Int J Mol Sci 2023; 24:12488. [PMID: 37569863 PMCID: PMC10419900 DOI: 10.3390/ijms241512488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023] Open
Abstract
Mitochondria, far beyond their prominent role as cellular powerhouses, are complex cellular organelles active as central metabolic hubs that are capable of integrating and controlling several signaling pathways essential for neurological processes, including neurogenesis and neuroplasticity. On the other hand, mitochondria are themselves regulated from a series of signaling proteins to achieve the best efficiency in producing energy, in establishing a network and in performing their own de novo synthesis or clearance. Dysfunctions in signaling processes that control mitochondrial biogenesis, dynamics and bioenergetics are increasingly associated with impairment in brain development and involved in a wide variety of neurodevelopmental disorders. Here, we review recent evidence proving the emerging role of mitochondria as master regulators of brain bioenergetics, highlighting their control skills in brain neurodevelopment and cognition. We analyze, from a mechanistic point of view, mitochondrial bioenergetic dysfunction as causally interrelated to the origins of typical genetic intellectual disability-related neurodevelopmental disorders, such as Down, Rett and Fragile X syndromes. Finally, we discuss whether mitochondria can become therapeutic targets to improve brain development and function from a holistic perspective.
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Affiliation(s)
- Daniela Valenti
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via G. Amendola 122/O, 70126 Bari, Italy
| | - Rosa Anna Vacca
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via G. Amendola 122/O, 70126 Bari, Italy
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16
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Boyarko B, Podvin S, Greenberg B, Momper JD, Huang Y, Gerwick WH, Bang AG, Quinti L, Griciuc A, Kim DY, Tanzi RE, Feldman HH, Hook V. Evaluation of bumetanide as a potential therapeutic agent for Alzheimer's disease. Front Pharmacol 2023; 14:1190402. [PMID: 37601062 PMCID: PMC10436590 DOI: 10.3389/fphar.2023.1190402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 06/28/2023] [Indexed: 08/22/2023] Open
Abstract
Therapeutics discovery and development for Alzheimer's disease (AD) has been an area of intense research to alleviate memory loss and the underlying pathogenic processes. Recent drug discovery approaches have utilized in silico computational strategies for drug candidate selection which has opened the door to repurposing drugs for AD. Computational analysis of gene expression signatures of patients stratified by the APOE4 risk allele of AD led to the discovery of the FDA-approved drug bumetanide as a top candidate agent that reverses APOE4 transcriptomic brain signatures and improves memory deficits in APOE4 animal models of AD. Bumetanide is a loop diuretic which inhibits the kidney Na+-K+-2Cl- cotransporter isoform, NKCC2, for the treatment of hypertension and edema in cardiovascular, liver, and renal disease. Electronic health record data revealed that patients exposed to bumetanide have lower incidences of AD by 35%-70%. In the brain, bumetanide has been proposed to antagonize the NKCC1 isoform which mediates cellular uptake of chloride ions. Blocking neuronal NKCC1 leads to a decrease in intracellular chloride and thus promotes GABAergic receptor mediated hyperpolarization, which may ameliorate disease conditions associated with GABAergic-mediated depolarization. NKCC1 is expressed in neurons and in all brain cells including glia (oligodendrocytes, microglia, and astrocytes) and the vasculature. In consideration of bumetanide as a repurposed drug for AD, this review evaluates its pharmaceutical properties with respect to its estimated brain levels across doses that can improve neurologic disease deficits of animal models to distinguish between NKCC1 and non-NKCC1 mechanisms. The available data indicate that bumetanide efficacy may occur at brain drug levels that are below those required for inhibition of the NKCC1 transporter which implicates non-NKCC1 brain mechansims for improvement of brain dysfunctions and memory deficits. Alternatively, peripheral bumetanide mechanisms may involve cells outside the central nervous system (e.g., in epithelia and the immune system). Clinical bumetanide doses for improved neurological deficits are reviewed. Regardless of mechanism, the efficacy of bumetanide to improve memory deficits in the APOE4 model of AD and its potential to reduce the incidence of AD provide support for clinical investigation of bumetanide as a repurposed AD therapeutic agent.
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Affiliation(s)
- Ben Boyarko
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Barry Greenberg
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jeremiah D. Momper
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA, United States
- Departments of Neurology and Pathology, University of California, San Francisco, San Francisco, CA, United States
| | - William H. Gerwick
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Anne G. Bang
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys, San Diego, CA, United States
| | - Luisa Quinti
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Ana Griciuc
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Doo Yeon Kim
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Rudolph E. Tanzi
- Genetics and Aging Research Unit, McCance Center for Brain Health, Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
| | - Howard H. Feldman
- Department of Neurosciences and Department of Pharmacology, University of California, San Diego, San Diego, United States
- Alzheimer’s Disease Cooperative Study, University of California, San Diego, La Jolla, CA, United States
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
- Department of Neurosciences and Department of Pharmacology, University of California, San Diego, San Diego, United States
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17
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van van Hugte EJH, Schubert D, Nadif Kasri N. Excitatory/inhibitory balance in epilepsies and neurodevelopmental disorders: Depolarizing γ-aminobutyric acid as a common mechanism. Epilepsia 2023; 64:1975-1990. [PMID: 37195166 DOI: 10.1111/epi.17651] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 05/13/2023] [Accepted: 05/15/2023] [Indexed: 05/18/2023]
Abstract
Epilepsy is one of the most common neurological disorders. Although many factors contribute to epileptogenesis, seizure generation is mostly linked to hyperexcitability due to alterations in excitatory/inhibitory (E/I) balance. The common hypothesis is that reduced inhibition, increased excitation, or both contribute to the etiology of epilepsy. Increasing evidence shows that this view is oversimplistic, and that increased inhibition through depolarizing γ-aminobutyric acid (GABA) similarly contributes to epileptogenisis. In early development, GABA signaling is depolarizing, inducing outward Cl- currents due to high intracellular Cl- concentrations. During maturation, the mechanisms of GABA action shift from depolarizing to hyperpolarizing, a critical event during brain development. Altered timing of this shift is associated with both neurodevelopmental disorders and epilepsy. Here, we consider the different ways that depolarizing GABA contributes to altered E/I balance and epileptogenesis, and discuss that alterations in depolarizing GABA could be a common denominator underlying seizure generation in neurodevelopmental disorders and epilepsies.
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Affiliation(s)
- Eline J H van van Hugte
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
- Department of Epileptology, Academic Centre for Epileptology (ACE) Kempenhaeghe, Heeze, the Netherlands
| | - Dirk Schubert
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
| | - Nael Nadif Kasri
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
- Department of Epileptology, Academic Centre for Epileptology (ACE) Kempenhaeghe, Heeze, the Netherlands
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18
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Peerboom C, de Kater S, Jonker N, Rieter MPJM, Wijne T, Wierenga CJ. Delaying the GABA Shift Indirectly Affects Membrane Properties in the Developing Hippocampus. J Neurosci 2023; 43:5483-5500. [PMID: 37438107 PMCID: PMC10376938 DOI: 10.1523/jneurosci.0251-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023] Open
Abstract
During the first two postnatal weeks, intraneuronal chloride concentrations in rodents gradually decrease, causing a shift from depolarizing to hyperpolarizing GABA responses. The postnatal GABA shift is delayed in rodent models for neurodevelopmental disorders and in human patients, but the impact of a delayed GABA shift on the developing brain remains obscure. Here we examine the direct and indirect consequences of a delayed postnatal GABA shift on network development in organotypic hippocampal cultures made from 6- to 7-d-old mice by treating the cultures for 1 week with VU0463271, a specific inhibitor of the chloride exporter KCC2. We verified that VU treatment delayed the GABA shift and kept GABA signaling depolarizing until DIV9. We found that the structural and functional development of excitatory and inhibitory synapses at DIV9 was not affected after VU treatment. In line with previous studies, we observed that GABA signaling was already inhibitory in control and VU-treated postnatal slices. Surprisingly, 14 d after the VU treatment had ended (DIV21), we observed an increased frequency of spontaneous inhibitory postsynaptic currents in CA1 pyramidal cells, while excitatory currents were not changed. Synapse numbers and release probability were unaffected. We found that dendrite-targeting interneurons in the stratum radiatum had an elevated resting membrane potential, while pyramidal cells were less excitable compared with control slices. Our results show that depolarizing GABA signaling does not promote synapse formation after P7, and suggest that postnatal intracellular chloride levels indirectly affect membrane properties in a cell-specific manner.SIGNIFICANCE STATEMENT During brain development, the action of neurotransmitter GABA shifts from depolarizing to hyperpolarizing. This shift is a thought to play a critical role in synapse formation. A delayed shift is common in rodent models for neurodevelopmental disorders and in human patients, but its consequences for synaptic development remain obscure. Here, we delayed the GABA shift by 1 week in organotypic hippocampal cultures and carefully examined the consequences for circuit development. We find that delaying the shift has no direct effects on synaptic development, but instead leads to indirect, cell type-specific changes in membrane properties. Our data call for careful assessment of alterations in cellular excitability in neurodevelopmental disorders.
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Affiliation(s)
- Carlijn Peerboom
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Sam de Kater
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Nikki Jonker
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Marijn P J M Rieter
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Tessel Wijne
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Corette J Wierenga
- Cell Biology, Neurobiology and Biophysics, Biology Department, Utrecht University, Utrecht, 3584 CH, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, 6525 AJ, The Netherlands
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19
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Rahn RM, Yen A, Chen S, Gaines SH, Bice AR, Brier LM, Swift RG, Lee L, Maloney SE, Culver JP, Dougherty JD. Mecp2 deletion results in profound alterations of developmental and adult functional connectivity. Cereb Cortex 2023; 33:7436-7453. [PMID: 36897048 PMCID: PMC10267622 DOI: 10.1093/cercor/bhad050] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 03/11/2023] Open
Abstract
As a regressive neurodevelopmental disorder with a well-established genetic cause, Rett syndrome and its Mecp2 loss-of-function mouse model provide an excellent opportunity to define potentially translatable functional signatures of disease progression, as well as offer insight into the role of Mecp2 in functional circuit development. Thus, we applied widefield optical fluorescence imaging to assess mesoscale calcium functional connectivity (FC) in the Mecp2 cortex both at postnatal day (P)35 in development and during the disease-related decline. We found that FC between numerous cortical regions was disrupted in Mecp2 mutant males both in juvenile development and early adulthood. Female Mecp2 mice displayed an increase in homotopic contralateral FC in the motor cortex at P35 but not in adulthood, where instead more posterior parietal regions were implicated. An increase in the amplitude of connection strength, both with more positive correlations and more negative anticorrelations, was observed across the male cortex in numerous functional regions. Widespread rescue of MeCP2 protein in GABAergic neurons rescued none of these functional deficits, nor, surprisingly, the expected male lifespan. Altogether, the female results identify early signs of disease progression, while the results in males indicate MeCP2 protein is required for typical FC in the brain.
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Affiliation(s)
- Rachel M Rahn
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Allen Yen
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Siyu Chen
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Seana H Gaines
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Lindsey M Brier
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Raylynn G Swift
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - LeiLani Lee
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Susan E Maloney
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Intellectual and Developmental Disabilities Research Center, 660 South Euclid Avenue, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Joseph P Culver
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Physics, Washington University School of Arts and Sciences, 1 Brookings Drive, St. Louis, MO 63130, United States
- Department of Biomedical Engineering, Washington University School of Engineering, 1 Brookings Drive, St. Louis, MO 63130, United States
| | - Joseph D Dougherty
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Intellectual and Developmental Disabilities Research Center, 660 South Euclid Avenue, Washington University School of Medicine, St. Louis, MO 63110, United States
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20
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Simonnet C, Sinha M, Goutierre M, Moutkine I, Daumas S, Poncer JC. Silencing KCC2 in mouse dorsal hippocampus compromises spatial and contextual memory. Neuropsychopharmacology 2023; 48:1067-1077. [PMID: 36302847 PMCID: PMC10209115 DOI: 10.1038/s41386-022-01480-5] [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: 04/13/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022]
Abstract
Delayed upregulation of the neuronal chloride extruder KCC2 underlies the progressive shift in GABA signaling polarity during development. Conversely, KCC2 downregulation is observed in a variety of neurological and psychiatric disorders often associated with cognitive impairment. Reduced KCC2 expression and function in mature networks may disrupt GABA signaling and promote anomalous network activities underlying these disorders. However, the causal link between KCC2 downregulation, altered brain rhythmogenesis, and cognitive function remains elusive. Here, by combining behavioral exploration with in vivo electrophysiology we assessed the impact of chronic KCC2 downregulation in mouse dorsal hippocampus and showed it compromises both spatial and contextual memory. This was associated with altered hippocampal rhythmogenesis and neuronal hyperexcitability, with increased burst firing in CA1 neurons during non-REM sleep. Reducing neuronal excitability with terbinafine, a specific Task-3 leak potassium channel opener, occluded the impairment of contextual memory upon KCC2 knockdown. Our results establish a causal relationship between KCC2 expression and cognitive performance and suggest that non-epileptiform rhythmopathies and neuronal hyperexcitability are central to the deficits caused by KCC2 downregulation in the adult mouse brain.
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Affiliation(s)
- Clémence Simonnet
- Inserm UMR-S 1270, 75005, Paris, France
- Sorbonne Université, 75005, Paris, France
- Institut du Fer à Moulin, 75005, Paris, France
- Basic Neuroscience Department, Centre Medical Universitaire, 1211, Geneva, Switzerland
| | - Manisha Sinha
- Inserm UMR-S 1270, 75005, Paris, France
- Sorbonne Université, 75005, Paris, France
- Institut du Fer à Moulin, 75005, Paris, France
| | - Marie Goutierre
- Inserm UMR-S 1270, 75005, Paris, France
- Sorbonne Université, 75005, Paris, France
- Institut du Fer à Moulin, 75005, Paris, France
| | - Imane Moutkine
- Inserm UMR-S 1270, 75005, Paris, France
- Sorbonne Université, 75005, Paris, France
- Institut du Fer à Moulin, 75005, Paris, France
| | - Stéphanie Daumas
- Sorbonne Université, 75005, Paris, France
- Neuroscience Paris Seine-Institut de Biologie Paris Seine (NPS-IBPS), 75005, Paris, France
| | - Jean Christophe Poncer
- Inserm UMR-S 1270, 75005, Paris, France.
- Sorbonne Université, 75005, Paris, France.
- Institut du Fer à Moulin, 75005, Paris, France.
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21
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Molinaro G, Huber KM, McCullagh EA, Thomson SR. Editorial: Recent advances in mechanisms and therapeutics for Fragile X Syndrome and autism. Front Neurosci 2023; 17:1187799. [PMID: 37266542 PMCID: PMC10230571 DOI: 10.3389/fnins.2023.1187799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/27/2023] [Indexed: 06/03/2023] Open
Affiliation(s)
- Gemma Molinaro
- Department of Neuroscience, O'Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Kimberly M. Huber
- Department of Neuroscience, O'Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Elizabeth A. McCullagh
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, United States
| | - Sophie R. Thomson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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22
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Egawa K, Watanabe M, Shiraishi H, Sato D, Takahashi Y, Nishio S, Fukuda A. Imbalanced expression of cation-chloride cotransporters as a potential therapeutic target in an Angelman syndrome mouse model. Sci Rep 2023; 13:5685. [PMID: 37069177 PMCID: PMC10110603 DOI: 10.1038/s41598-023-32376-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 03/27/2023] [Indexed: 04/19/2023] Open
Abstract
Angelman syndrome is a neurodevelopmental disorder caused by loss of function of the maternally expressed UBE3A gene. Treatments for the main manifestations, including cognitive dysfunction or epilepsy, are still under development. Recently, the Cl- importer Na+-K+-Cl- cotransporter 1 (NKCC1) and the Cl- exporter K+-Cl- cotransporter 2 (KCC2) have garnered attention as therapeutic targets for many neurological disorders. Dysregulation of neuronal intracellular Cl- concentration ([Cl-]i) is generally regarded as one of the mechanisms underlying neuronal dysfunction caused by imbalanced expression of these cation-chloride cotransporters (CCCs). Here, we analyzed the regulation of [Cl-]i and the effects of bumetanide, an NKCC1 inhibitor, in Angelman syndrome models (Ube3am-/p+ mice). We observed increased NKCC1 expression and decreased KCC2 expression in the hippocampi of Ube3am-/p+ mice. The average [Cl-]i of CA1 pyramidal neurons was not significantly different but demonstrated greater variance in Ube3am-/p+ mice. Tonic GABAA receptor-mediated Cl- conductance was reduced, which may have contributed to maintaining the normal average [Cl-]i. Bumetanide administration restores cognitive dysfunction in Ube3am-/p+ mice. Seizure susceptibility was also reduced regardless of the genotype. These results suggest that an imbalanced expression of CCCs is involved in the pathophysiological mechanism of Ube3am-/p+ mice, although the average [Cl-]i is not altered. The blockage of NKCC1 may be a potential therapeutic strategy for patients with Angelman syndrome.
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Affiliation(s)
- Kiyoshi Egawa
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan.
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-Ku, Hamamatsu City, Shizuoka, 431-3192, Japan
| | - Hideaki Shiraishi
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Daisuke Sato
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Yukitoshi Takahashi
- Department of Clinical Research, National Epilepsy Center, NHO, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-Ku, Shizuoka, 420-8688, Japan
| | - Saori Nishio
- Department of Rheumatology, Endocrinology, and Nephrology, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-Ku, Hamamatsu City, Shizuoka, 431-3192, Japan
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23
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Fogarty MJ. Inhibitory Synaptic Influences on Developmental Motor Disorders. Int J Mol Sci 2023; 24:ijms24086962. [PMID: 37108127 PMCID: PMC10138861 DOI: 10.3390/ijms24086962] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
During development, GABA and glycine play major trophic and synaptic roles in the establishment of the neuromotor system. In this review, we summarise the formation, function and maturation of GABAergic and glycinergic synapses within neuromotor circuits during development. We take special care to discuss the differences in limb and respiratory neuromotor control. We then investigate the influences that GABAergic and glycinergic neurotransmission has on two major developmental neuromotor disorders: Rett syndrome and spastic cerebral palsy. We present these two syndromes in order to contrast the approaches to disease mechanism and therapy. While both conditions have motor dysfunctions at their core, one condition Rett syndrome, despite having myriad symptoms, has scientists focused on the breathing abnormalities and their alleviation-to great clinical advances. By contrast, cerebral palsy remains a scientific quagmire or poor definitions, no widely adopted model and a lack of therapeutic focus. We conclude that the sheer abundance of diversity of inhibitory neurotransmitter targets should provide hope for intractable conditions, particularly those that exhibit broad spectra of dysfunction-such as spastic cerebral palsy and Rett syndrome.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55902, USA
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24
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Zayan U, Caccialupi Da Prato L, Muscatelli F, Matarazzo V. Modulation of the thermosensory system by oxytocin. Front Mol Neurosci 2023; 15:1075305. [PMID: 36698777 PMCID: PMC9868264 DOI: 10.3389/fnmol.2022.1075305] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/06/2022] [Indexed: 01/11/2023] Open
Abstract
Oxytocin (OT) is a neurohormone involved early in neurodevelopment and is implicated in multiple functions, including sensory modulation. Evidence of such modulation has been observed for different sensory modalities in both healthy and pathological conditions. This review summarizes the pleiotropic modulation that OT can exercise on an often overlooked sensory system: thermosensation. This system allows us to sense temperature variations and compensate for the variation to maintain a stable core body temperature. Oxytocin modulates autonomic and behavioral mechanisms underlying thermoregulation at both central and peripheral levels. Hyposensitivity or hypersensitivity for different sensory modalities, including thermosensitivity, is a common feature in autism spectrum disorder (ASD), recapitulated in several ASD mouse models. These sensory dysregulations occur early in post-natal development and are correlated with dysregulation of the oxytocinergic system. In this study, we discussed the potential link between thermosensory atypia and the dysregulation of the oxytocinergic system in ASD.
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25
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Miles KD, Doll CA. Chloride imbalance in Fragile X syndrome. Front Neurosci 2022; 16:1008393. [PMID: 36312023 PMCID: PMC9596984 DOI: 10.3389/fnins.2022.1008393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/20/2022] [Indexed: 11/26/2022] Open
Abstract
Developmental changes in ionic balance are associated with crucial hallmarks in neural circuit formation, including changes in excitation and inhibition, neurogenesis, and synaptogenesis. Neuronal excitability is largely mediated by ionic concentrations inside and outside of the cell, and chloride (Cl-) ions are highly influential in early neurodevelopmental events. For example, γ-aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the mature central nervous system (CNS). However, during early development GABA can depolarize target neurons, and GABAergic depolarization is implicated in crucial neurodevelopmental processes. This developmental shift of GABAergic neurotransmission from depolarizing to hyperpolarizing output is induced by changes in Cl- gradients, which are generated by the relative expression of Cl- transporters Nkcc1 and Kcc2. Interestingly, the GABA polarity shift is delayed in Fragile X syndrome (FXS) models; FXS is one of the most common heritable neurodevelopmental disorders. The RNA binding protein FMRP, encoded by the gene Fragile X Messenger Ribonucleoprotein-1 (Fmr1) and absent in FXS, appears to regulate chloride transporter expression. This could dramatically influence FXS phenotypes, as the syndrome is hypothesized to be rooted in defects in neural circuit development and imbalanced excitatory/inhibitory (E/I) neurotransmission. In this perspective, we summarize canonical Cl- transporter expression and investigate altered gene and protein expression of Nkcc1 and Kcc2 in FXS models. We then discuss interactions between Cl- transporters and neurotransmission complexes, and how these links could cause imbalances in inhibitory neurotransmission that may alter mature circuits. Finally, we highlight current therapeutic strategies and promising new directions in targeting Cl- transporter expression in FXS patients.
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Affiliation(s)
| | - Caleb Andrew Doll
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Children’s Hospital Colorado, Aurora, CO, United States
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26
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Ash RT, Palagina G, Fernandez-Leon JA, Park J, Seilheimer R, Lee S, Sabharwal J, Reyes F, Wang J, Lu D, Sarfraz M, Froudarakis E, Tolias AS, Wu SM, Smirnakis SM. Increased Reliability of Visually-Evoked Activity in Area V1 of the MECP2-Duplication Mouse Model of Autism. J Neurosci 2022; 42:6469-6482. [PMID: 35831173 PMCID: PMC9398540 DOI: 10.1523/jneurosci.0654-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/15/2022] [Accepted: 06/02/2022] [Indexed: 11/21/2022] Open
Abstract
Atypical sensory processing is now thought to be a core feature of the autism spectrum. Influential theories have proposed that both increased and decreased neural response reliability within sensory systems could underlie altered sensory processing in autism. Here, we report evidence for abnormally increased reliability of visual-evoked responses in layer 2/3 neurons of adult male and female primary visual cortex in the MECP2-duplication syndrome animal model of autism. Increased response reliability was due in part to decreased response amplitude, decreased fluctuations in endogenous activity, and an abnormal decoupling of visual-evoked activity from endogenous activity. Similar to what was observed neuronally, the optokinetic reflex occurred more reliably at low contrasts in mutant mice compared with controls. Retinal responses did not explain our observations. These data suggest that the circuit mechanisms for combining sensory-evoked and endogenous signal and noise processes may be altered in this form of syndromic autism.SIGNIFICANCE STATEMENT Atypical sensory processing is now thought to be a core feature of the autism spectrum. Influential theories have proposed that both increased and decreased neural response reliability within sensory systems could underlie altered sensory processing in autism. Here, we report evidence for abnormally increased reliability of visual-evoked responses in primary visual cortex of the animal model for MECP2-duplication syndrome, a high-penetrance single-gene cause of autism. Visual-evoked activity was abnormally decoupled from endogenous activity in mutant mice, suggesting in line with the influential "hypo-priors" theory of autism that sensory priors embedded in endogenous activity may have less influence on perception in autism.
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Affiliation(s)
- Ryan T Ash
- Department of Psychiatry, Stanford University School of Medicine, Stanford, California 94305
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Ganna Palagina
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Jose A Fernandez-Leon
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires and Instituto de Investigación en Tecnología Informática Avanzada, Exact Sciences Faculty-Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Argentina
| | - Jiyoung Park
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030
| | - Rob Seilheimer
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Sangkyun Lee
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Jasdeep Sabharwal
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland 21205
| | - Fredy Reyes
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Jing Wang
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030
| | - Dylan Lu
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Muhammad Sarfraz
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Emmanouil Froudarakis
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- FORTH, Heraklion, Crete, Greece 70013
| | - Andreas S Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Samuel M Wu
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030
| | - Stelios M Smirnakis
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
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27
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Horvath PM, Piazza MK, Kavalali ET, Monteggia LM. MeCP2 loss-of-function dysregulates microRNAs regionally and disrupts excitatory/inhibitory synaptic transmission balance. Hippocampus 2022; 32:610-623. [PMID: 35851733 PMCID: PMC9344394 DOI: 10.1002/hipo.23455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 06/11/2022] [Accepted: 06/25/2022] [Indexed: 11/06/2022]
Abstract
Rett syndrome is a leading cause of intellectual disability in females primarily caused by loss of function mutations in the transcriptional regulator MeCP2. Loss of MeCP2 leads to a host of synaptic phenotypes that are believed to underlie Rett syndrome pathophysiology. Synaptic deficits vary by brain region upon MeCP2 loss, suggesting distinct molecular alterations leading to disparate synaptic outcomes. In this study, we examined the contribution of MeCP2's newly described role in miRNA regulation to regional molecular and synaptic impairments. Two miRNAs, miR-101a and miR-203, were identified and confirmed as upregulated in MeCP2 KO mice in the hippocampus and cortex, respectively. miR-101a overexpression in hippocampal cultures led to opposing effects at excitatory and inhibitory synapses and in spontaneous and evoked neurotransmission, revealing the potential for a single miRNA to broadly regulate synapse function in the hippocampus. These results highlight the importance of regional alterations in miRNA expression and the specific impact on synaptic function with potential implications for Rett syndrome.
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Affiliation(s)
- Patricia M. Horvath
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA,Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Michelle K. Piazza
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA,Neuroscience Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Ege T. Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Lisa M. Monteggia
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
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28
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Hui KK, Chater TE, Goda Y, Tanaka M. How Staying Negative Is Good for the (Adult) Brain: Maintaining Chloride Homeostasis and the GABA-Shift in Neurological Disorders. Front Mol Neurosci 2022; 15:893111. [PMID: 35875665 PMCID: PMC9305173 DOI: 10.3389/fnmol.2022.893111] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/10/2022] [Indexed: 01/27/2023] Open
Abstract
Excitatory-inhibitory (E-I) imbalance has been shown to contribute to the pathogenesis of a wide range of neurodevelopmental disorders including autism spectrum disorders, epilepsy, and schizophrenia. GABA neurotransmission, the principal inhibitory signal in the mature brain, is critically coupled to proper regulation of chloride homeostasis. During brain maturation, changes in the transport of chloride ions across neuronal cell membranes act to gradually change the majority of GABA signaling from excitatory to inhibitory for neuronal activation, and dysregulation of this GABA-shift likely contributes to multiple neurodevelopmental abnormalities that are associated with circuit dysfunction. Whilst traditionally viewed as a phenomenon which occurs during brain development, recent evidence suggests that this GABA-shift may also be involved in neuropsychiatric disorders due to the "dematuration" of affected neurons. In this review, we will discuss the cell signaling and regulatory mechanisms underlying the GABA-shift phenomenon in the context of the latest findings in the field, in particular the role of chloride cotransporters NKCC1 and KCC2, and furthermore how these regulatory processes are altered in neurodevelopmental and neuropsychiatric disorders. We will also explore the interactions between GABAergic interneurons and other cell types in the developing brain that may influence the GABA-shift. Finally, with a greater understanding of how the GABA-shift is altered in pathological conditions, we will briefly outline recent progress on targeting NKCC1 and KCC2 as a therapeutic strategy against neurodevelopmental and neuropsychiatric disorders associated with improper chloride homeostasis and GABA-shift abnormalities.
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Affiliation(s)
- Kelvin K. Hui
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Thomas E. Chater
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Synapse Biology Unit, Okinawa Institute for Science and Technology Graduate University, Onna, Japan
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Japan
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29
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Lu S, Chen Y, Wang Z. Advances in the pathogenesis of Rett syndrome using cell models. Animal Model Exp Med 2022; 5:532-541. [PMID: 35785421 PMCID: PMC9773312 DOI: 10.1002/ame2.12236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/05/2022] [Indexed: 12/30/2022] Open
Abstract
Rett syndrome (RTT) is a progressive neurodevelopmental disorder that occurs mainly in girls with a range of typical symptoms of autism spectrum disorders. MeCP2 protein loss-of-function in neural lineage cells is the main cause of RTT pathogenicity. As it is still hard to understand the mechanism of RTT on the basis of only clinical patients or animal models, cell models cultured in vitro play indispensable roles. Here we reviewed the research progress in the pathogenesis of RTT at the cellular level, summarized the preclinical-research-related applications, and prospected potential future development.
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Affiliation(s)
- Sijia Lu
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational MedicineKunming University of Science and TechnologyKunmingChina,Yunnan Key Laboratory of Primate Biomedical ResearchKunmingChina
| | - Yongchang Chen
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational MedicineKunming University of Science and TechnologyKunmingChina,Yunnan Key Laboratory of Primate Biomedical ResearchKunmingChina
| | - Zhengbo Wang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational MedicineKunming University of Science and TechnologyKunmingChina,Yunnan Key Laboratory of Primate Biomedical ResearchKunmingChina
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30
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Zhang WJ, Shi LL, Zhang L. Dysregulated cortical synaptic plasticity under methyl-CpG binding protein 2 deficiency and its implication in motor impairments. World J Psychiatry 2022; 12:673-682. [PMID: 35663301 PMCID: PMC9150038 DOI: 10.5498/wjp.v12.i5.673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/16/2021] [Accepted: 04/04/2022] [Indexed: 02/06/2023] Open
Abstract
Caused by the mutation of methyl-CpG binding protein 2 (MeCP2), Rett syndrome leads to a battery of severe neural dysfunctions including the regression of motor coordination and motor learning. Current understanding has revealed the motor cortex as the critical region mediating voluntary movement. In this review article, we will summarize major findings from human patients and animal models regarding the cortical synaptic plasticity under the regulation of MeCP2. We will also discuss how mutation of MeCP2 leads to the disruption of cortical circuitry homeostasis to cause motor deficits. Lastly, potential values of physical exercise and neuromodulation approaches to recover neural plasticity and motor function will be evaluated. All of this evidence may help to accelerate timely diagnosis and effective interventions for Rett syndrome patients.
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Affiliation(s)
- Wei-Jia Zhang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou 510632, Guangdong Province, China
| | - Ling-Ling Shi
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou 510632, Guangdong Province, China
| | - Li Zhang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou 510632, Guangdong Province, China
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31
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Antoine MW. Paradoxical Hyperexcitability in Disorders of Neurodevelopment. Front Mol Neurosci 2022; 15:826679. [PMID: 35571370 PMCID: PMC9102973 DOI: 10.3389/fnmol.2022.826679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/14/2022] [Indexed: 01/29/2023] Open
Abstract
Autism Spectrum Disorder (ASD), Rett syndrome (RTT) and Angelman Syndrome (AS) are neurodevelopmental disorders (NDDs) that share several clinical characteristics, including displays of repetitive movements, developmental delays, language deficits, intellectual disability, and increased susceptibility to epilepsy. While several reviews address the biological basis of non-seizure-related ASD phenotypes, here, I highlight some shared biological mechanisms that may contribute to increased seizure susceptibility. I focus on genetic studies identifying the anatomical origin of the seizure phenotype in loss-of-function, monogenic, mouse models of these NDDs, combined with insights gained from complementary studies quantifying levels of synaptic excitation and inhibition. Epilepsy is characterized by a sudden, abnormal increase in synchronous activity within neuronal networks, that is posited to arise from excess excitation, largely driven by reduced synaptic inhibition. Primarily for this reason, elevated network excitability is proposed to underlie the causal basis for the ASD, RTT, and AS phenotypes. Although, mouse models of these disorders replicate aspects of the human condition, i.e., hyperexcitability discharges or seizures on cortical electroencephalograms, measures at the synaptic level often reveal deficits in excitatory synaptic transmission, rather than too much excitation. Resolving this apparent paradox has direct implications regarding expected outcomes of manipulating GABAergic tone. In particular, in NDDs associated with seizures, cortical circuits can display reduced, rather than normal or increased levels of synaptic excitation, and therefore suggested treatments aimed at increasing inhibition could further promote hypoactivity instead of normality. In this review, I highlight shared mechanisms across animal models for ASD, RTT, and AS with reduced synaptic excitation that nevertheless promote hyperexcitability in cortical circuits.
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Affiliation(s)
- Michelle W. Antoine
- Section on Neural Circuits, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
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32
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Chen W, Cai W, Hoover B, Kahn CR. Insulin action in the brain: cell types, circuits, and diseases. Trends Neurosci 2022; 45:384-400. [PMID: 35361499 PMCID: PMC9035105 DOI: 10.1016/j.tins.2022.03.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/10/2022] [Accepted: 03/03/2022] [Indexed: 10/18/2022]
Abstract
Since its discovery over 100 years ago, insulin has been recognized as a key hormone in control of glucose homeostasis. Deficiencies of insulin signaling are central to diabetes and many other disorders. The brain is among the targets of insulin action, and insulin resistance is a major contributor to many diseases, including brain disorders. Here, we summarize key roles of insulin action in the brain and how this involves different brain cell types. Disordered brain insulin signaling can also contribute to neuropsychiatric diseases, affecting brain circuits involved in mood and cognition. Understanding of insulin signaling in different brain cell types/circuits and how these are altered in disease may lead to the development of new therapeutic approaches to these challenging disorders.
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Kong Y, Li QB, Yuan ZH, Jiang XF, Zhang GQ, Cheng N, Dang N. Multimodal Neuroimaging in Rett Syndrome With MECP2 Mutation. Front Neurol 2022; 13:838206. [PMID: 35280272 PMCID: PMC8904872 DOI: 10.3389/fneur.2022.838206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/24/2022] [Indexed: 01/11/2023] Open
Abstract
Rett syndrome (RTT) is a rare neurodevelopmental disorder characterized by severe cognitive, social, and physical impairments resulting from de novo mutations in the X-chromosomal methyl-CpG binding protein gene 2 (MECP2). While there is still no cure for RTT, exploring up-to date neurofunctional diagnostic markers, discovering new potential therapeutic targets, and searching for novel drug efficacy evaluation indicators are fundamental. Multiple neuroimaging studies on brain structure and function have been carried out in RTT-linked gene mutation carriers to unravel disease-specific imaging features and explore genotype-phenotype associations. Here, we reviewed the neuroimaging literature on this disorder. MRI morphologic studies have shown global atrophy of gray matter (GM) and white matter (WM) and regional variations in brain maturation. Diffusion tensor imaging (DTI) studies have demonstrated reduced fractional anisotropy (FA) in left peripheral WM areas, left major WM tracts, and cingulum bilaterally, and WM microstructural/network topology changes have been further found to be correlated with behavioral abnormalities in RTT. Cerebral blood perfusion imaging studies using single-photon emission CT (SPECT) or PET have evidenced a decreased global cerebral blood flow (CBF), particularly in prefrontal and temporoparietal areas, while magnetic resonance spectroscopy (MRS) and PET studies have contributed to unraveling metabolic alterations in patients with RTT. The results obtained from the available reports confirm that multimodal neuroimaging can provide new insights into a complex interplay between genes, neurotransmitter pathway abnormalities, disease-related behaviors, and clinical severity. However, common limitations related to the available studies include small sample sizes and hypothesis-based and region-specific approaches. We, therefore, conclude that this field is still in its early development phase and that multimodal/multisequence studies with improved post-processing technologies as well as combined PET–MRI approaches are urgently needed to further explore RTT brain alterations.
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Affiliation(s)
- Yu Kong
- Department of Medical Imaging, Affiliated Hospital of Jining Medical University, Jining, China
- *Correspondence: Yu Kong
| | - Qiu-bo Li
- Department of Pediatrics, Affiliated Hospital of Jining Medical University, Jining, China
| | - Zhao-hong Yuan
- Department of Pediatric Rehabilitation, Affiliated Hospital of Jining Medical University, Jining, China
| | - Xiu-fang Jiang
- Department of Pediatric Rehabilitation, Affiliated Hospital of Jining Medical University, Jining, China
| | - Gu-qing Zhang
- Department of Medical Imaging, Affiliated Hospital of Jining Medical University, Jining, China
- Gu-qing Zhang
| | - Nan Cheng
- Department of Medical Imaging, Affiliated Hospital of Jining Medical University, Jining, China
| | - Na Dang
- Department of Medical Imaging, Affiliated Hospital of Jining Medical University, Jining, China
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Li W. Excitation and Inhibition Imbalance in Rett Syndrome. Front Neurosci 2022; 16:825063. [PMID: 35250460 PMCID: PMC8894599 DOI: 10.3389/fnins.2022.825063] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/31/2022] [Indexed: 12/12/2022] Open
Abstract
A loss of the excitation/inhibition (E/I) balance in the neural circuit has emerged as a common neuropathological feature in many neurodevelopmental disorders. Rett syndrome (RTT), a prevalent neurodevelopmental disorder that affects 1:10,000-15,000 women globally, is caused by loss-of-function mutations in the Methyl-CpG-binding Protein-2 (Mecp2) gene. E/I imbalance is recognized as the leading cellular and synaptic hallmark that is fundamental to diverse RTT neurological symptoms, including stereotypic hand movements, impaired motor coordination, breathing irregularities, seizures, and learning/memory dysfunctions. E/I balance in RTT is not homogeneously altered but demonstrates brain region and cell type specificity instead. In this review, I elaborate on the current understanding of the loss of E/I balance in a range of brain areas at molecular and cellular levels. I further describe how the underlying cellular mechanisms contribute to the disturbance of the proper E/I ratio. Last, I discuss current pharmacologic innervations for RTT and their role in modifying the E/I balance.
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Affiliation(s)
- Wei Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
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35
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Terashima H, Minatohara K, Maruoka H, Okabe S. Imaging neural circuit pathology of autism spectrum disorders: autism-associated genes, animal models and the application of in vivo two-photon imaging. Microscopy (Oxf) 2022; 71:i81-i99. [DOI: 10.1093/jmicro/dfab039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/11/2021] [Accepted: 11/08/2021] [Indexed: 11/12/2022] Open
Abstract
Abstract
Recent advances in human genetics identified genetic variants involved in causing autism spectrum disorders (ASDs). Mouse models that mimic mutations found in patients with ASD exhibit behavioral phenotypes consistent with ASD symptoms. These mouse models suggest critical biological factors of ASD etiology. Another important implication of ASD genetics is the enrichment of ASD risk genes in molecules involved in developing synapses and regulating neural circuit function. Sophisticated in vivo imaging technologies applied to ASD mouse models identify common synaptic impairments in the neocortex, with genetic-mutation-specific defects in local neural circuits. In this article, we review synapse- and circuit-level phenotypes identified by in vivo two-photon imaging in multiple mouse models of ASD and discuss the contributions of altered synapse properties and neural circuit activity to ASD pathogenesis.
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Affiliation(s)
- Hiroshi Terashima
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Keiichiro Minatohara
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hisato Maruoka
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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36
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Lodovichi C, Ratto GM, Trevelyan AJ, Arosio D. Genetically encoded sensors for Chloride concentration. J Neurosci Methods 2022; 368:109455. [PMID: 34952088 DOI: 10.1016/j.jneumeth.2021.109455] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 12/11/2021] [Accepted: 12/18/2021] [Indexed: 12/12/2022]
Abstract
Insights into chloride regulation in neurons have come slowly, but they are likely to be critical for our understanding of how the brain works. The reason is that the intracellular Cl- level ([Cl-]i) is the key determinant of synaptic inhibitory function, and this in turn dictates all manner of neuronal network function. The true impact on the network will only be apparent, however, if Cl- is measured at many locations at once (multiple neurons, and also across the subcellular compartments of single neurons), which realistically, can only be achieved using imaging. The development of genetically-encoded anion biosensors (GABs) brings the additional benefit that Cl- imaging may be done in identified cell-classes and hopefully in subcellular compartments. Here, we describe the historical background and motivation behind the development of these sensors and how they have been used so far. There are, however, still major limitations for their use, the most important being the fact that all GABs are sensitive to both pH and Cl-. Disambiguating the two signals has proved a major challenge, but there are potential solutions; notable among these is ClopHensor, which has now been developed for in vivo measurements of both ion species. We also speculate on how these biosensors may yet be improved, and how this could advance our understanding of Cl- regulation and its impact on brain function.
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Affiliation(s)
- Claudia Lodovichi
- Neuroscience Institute-CNR, Depart. Biomedical Sciences, Unipd, Padova, Veneto Institute of Molecular Medicine, Padova Neuroscience Center, Padova, Italy.
| | - Gian Michele Ratto
- National Enterprise for nanoScience and nanoTechnology (NEST), Istituto Nanoscienze, Consiglio Nazionale delle Ricerche (CNR) and Scuola Normale Superiore Pisa, 56127 Pisa, Italy
| | - Andrew J Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Daniele Arosio
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Biofisica, 38123 Trento, Italy.
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Abstract
Neuroplasticity, i.e., the modifiability of the brain, is different in development and adulthood. The first includes changes in: (i) neurogenesis and control of neuron number; (ii) neuronal migration; (iii) differentiation of the somato-dendritic and axonal phenotypes; (iv) formation of connections; (v) cytoarchitectonic differentiation. These changes are often interrelated and can lead to: (vi) system-wide modifications of brain structure as well as to (vii) acquisition of specific functions such as ocular dominance or language. Myelination appears to be plastic both in development and adulthood, at least, in rodents. Adult neuroplasticity is limited, and is mainly expressed as changes in the strength of excitatory and inhibitory synapses while the attempts to regenerate connections have met with limited success. The outcomes of neuroplasticity are not necessarily adaptive, but can also be the cause of neurological and psychiatric pathologies.
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Al Awabdh S, Donneger F, Goutierre M, Séveno M, Vigy O, Weinzettl P, Russeau M, Moutkine I, Lévi S, Marin P, Poncer JC. Gephyrin Interacts with the K-Cl Cotransporter KCC2 to Regulate Its Surface Expression and Function in Cortical Neurons. J Neurosci 2022; 42:166-182. [PMID: 34810232 PMCID: PMC8802937 DOI: 10.1523/jneurosci.2926-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 08/31/2021] [Accepted: 10/17/2021] [Indexed: 11/21/2022] Open
Abstract
The K+-Cl- cotransporter KCC2, encoded by the Slc12a5 gene, is a neuron-specific chloride extruder that tunes the strength and polarity of GABAA receptor-mediated transmission. In addition to its canonical ion transport function, KCC2 also regulates spinogenesis and excitatory synaptic function through interaction with a variety of molecular partners. KCC2 is enriched in the vicinity of both glutamatergic and GABAergic synapses, the activity of which in turn regulates its membrane stability and function. KCC2 interaction with the submembrane actin cytoskeleton via 4.1N is known to control its anchoring near glutamatergic synapses on dendritic spines. However, the molecular determinants of KCC2 clustering near GABAergic synapses remain unknown. Here, we used proteomics to identify novel KCC2 interacting proteins in the adult rat neocortex. We identified both known and novel candidate KCC2 partners, including some involved in neuronal development and synaptic transmission. These include gephyrin, the main scaffolding molecule at GABAergic synapses. Gephyrin interaction with endogenous KCC2 was confirmed by immunoprecipitation from rat neocortical extracts. We showed that gephyrin stabilizes plasmalemmal KCC2 and promotes its clustering in hippocampal neurons, mostly but not exclusively near GABAergic synapses, thereby controlling KCC2-mediated chloride extrusion. This study identifies gephyrin as a novel KCC2 anchoring molecule that regulates its membrane expression and function in cortical neurons.SIGNIFICANCE STATEMENT Fast synaptic inhibition in the brain is mediated by chloride-permeable GABAA receptors (GABAARs) and therefore relies on transmembrane chloride gradients. In neurons, these gradients are primarily maintained by the K/Cl cotransporter KCC2. Therefore, understanding the mechanisms controlling KCC2 expression and function is crucial to understand its physiological regulation and rescue its function in the pathology. KCC2 function depends on its membrane expression and clustering, but the underlying mechanisms remain unknown. We describe the interaction between KCC2 and gephyrin, the main scaffolding protein at inhibitory synapses. We show that gephyrin controls plasmalemmal KCC2 clustering and that loss of gephyrin compromises KCC2 function. Our data suggest functional units comprising GABAARs, gephyrin, and KCC2 act to regulate synaptic GABA signaling.
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Affiliation(s)
- Sana Al Awabdh
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Florian Donneger
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Marie Goutierre
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Martial Séveno
- BCM, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Oana Vigy
- IGF, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Pauline Weinzettl
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
- Institute of Biotechnology, University of Applied Sciences, Krems, Austria
| | - Marion Russeau
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Imane Moutkine
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Sabine Lévi
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
| | - Philippe Marin
- IGF, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Jean Christophe Poncer
- INSERM UMR-S 1270, 75005 Paris, France
- Sorbonne Université, 75005 Paris, France
- Institut du Fer à Moulin, 75005 Paris, France
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39
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Shovlin S, Delepine C, Swanson L, Bach S, Sahin M, Sur M, Kaufmann WE, Tropea D. Molecular Signatures of Response to Mecasermin in Children With Rett Syndrome. Front Neurosci 2022; 16:868008. [PMID: 35712450 PMCID: PMC9197456 DOI: 10.3389/fnins.2022.868008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/26/2022] [Indexed: 11/21/2022] Open
Abstract
Rett syndrome (RTT) is a devastating neurodevelopmental disorder without effective treatments. Attempts at developing targetted therapies have been relatively unsuccessful, at least in part, because the genotypical and phenotypical variability of the disorder. Therefore, identification of biomarkers of response and patients' stratification are high priorities. Administration of Insulin-like Growth Factor 1 (IGF-1) and related compounds leads to significant reversal of RTT-like symptoms in preclinical mouse models. However, improvements in corresponding clinical trials have not been consistent. A 20-weeks phase I open label trial of mecasermin (recombinant human IGF-1) in children with RTT demonstrated significant improvements in breathing phenotypes. However, a subsequent randomised controlled phase II trial did not show significant improvements in primary outcomes although two secondary clinical endpoints showed positive changes. To identify molecular biomarkers of response and surrogate endpoints, we used RNA sequencing to measure differential gene expression in whole blood samples of participants in the abovementioned phase I mecasermin trial. When all participants (n = 9) were analysed, gene expression was unchanged during the study (baseline vs. end of treatment, T0-T3). However, when participants were subclassified in terms of breathing phenotype improvement, specifically by their plethysmography-based apnoea index, individuals with moderate-severe apnoea and breathing improvement (Responder group) displayed significantly different transcript profiles compared to the other participants in the study (Mecasermin Study Reference group, MSR). Many of the differentially expressed genes are involved in the regulation of cell cycle processes and immune responses, as well as in IGF-1 signalling and breathing regulation. While the Responder group showed limited gene expression changes in response to mecasermin, the MSR group displayed marked differences in the expression of genes associated with inflammatory processes (e.g., neutrophil activation, complement activation) throughout the trial. Our analyses revealed gene expression profiles associated with severe breathing phenotype and its improvement after mecasermin administration in RTT, and suggest that inflammatory/immune pathways and IGF-1 signalling contribute to treatment response. Overall, these data support the notion that transcript profiles have potential as biomarkers of response to IGF-1 and related compounds.
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Affiliation(s)
- Stephen Shovlin
- Neuropsychiatric Genetics, Trinity Center for Health Sciences, Trinity Translational Medicine Institute, St James Hospital, Dublin, Ireland
| | - Chloe Delepine
- Department of Brain and Cognitive Sciences, Simons Center for the Social Brain, Picower Institute for Learning and Memory, MIT, Cambridge, MA, United States
| | - Lindsay Swanson
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - Snow Bach
- Neuropsychiatric Genetics, Trinity Center for Health Sciences, Trinity Translational Medicine Institute, St James Hospital, Dublin, Ireland
| | - Mustafa Sahin
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Simons Center for the Social Brain, Picower Institute for Learning and Memory, MIT, Cambridge, MA, United States
| | - Walter E Kaufmann
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States.,Department of Neurology, Boston Children's Hospital, Boston, MA, United States
| | - Daniela Tropea
- Neuropsychiatric Genetics, Trinity Center for Health Sciences, Trinity Translational Medicine Institute, St James Hospital, Dublin, Ireland.,Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland.,FutureNeuro, The SFI Research Centre for Chronic and Rare Neurological Diseases, Dublin, Ireland
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40
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Bach S, Shovlin S, Moriarty M, Bardoni B, Tropea D. Rett Syndrome and Fragile X Syndrome: Different Etiology With Common Molecular Dysfunctions. Front Cell Neurosci 2021; 15:764761. [PMID: 34867203 PMCID: PMC8640214 DOI: 10.3389/fncel.2021.764761] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/27/2021] [Indexed: 01/04/2023] Open
Abstract
Rett syndrome (RTT) and Fragile X syndrome (FXS) are two monogenetic neurodevelopmental disorders with complex clinical presentations. RTT is caused by mutations in the Methyl-CpG binding protein 2 gene (MECP2) altering the function of its protein product MeCP2. MeCP2 modulates gene expression by binding methylated CpG dinucleotides, and by interacting with transcription factors. FXS is caused by the silencing of the FMR1 gene encoding the Fragile X Mental Retardation Protein (FMRP), a RNA binding protein involved in multiple steps of RNA metabolism, and modulating the translation of thousands of proteins including a large set of synaptic proteins. Despite differences in genetic etiology, there are overlapping features in RTT and FXS, possibly due to interactions between MeCP2 and FMRP, and to the regulation of pathways resulting in dysregulation of common molecular signaling. Furthermore, basic physiological mechanisms are regulated by these proteins and might concur to the pathophysiology of both syndromes. Considering that RTT and FXS are disorders affecting brain development, and that most of the common targets of MeCP2 and FMRP are involved in brain activity, we discuss the mechanisms of synaptic function and plasticity altered in RTT and FXS, and we consider the similarities and the differences between these two disorders.
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Affiliation(s)
- Snow Bach
- School of Mathematical Sciences, Dublin City University, Dublin, Ireland.,Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland
| | - Stephen Shovlin
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland
| | | | - Barbara Bardoni
- Inserm, CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology, Université Côte d'Azur, Valbonne, France
| | - Daniela Tropea
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland.,Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland.,FutureNeuro, The SFI Research Centre for Chronic and Rare Neurological Diseases, Dublin, Ireland
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41
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Bertoni A, Schaller F, Tyzio R, Gaillard S, Santini F, Xolin M, Diabira D, Vaidyanathan R, Matarazzo V, Medina I, Hammock E, Zhang J, Chini B, Gaiarsa JL, Muscatelli F. Oxytocin administration in neonates shapes hippocampal circuitry and restores social behavior in a mouse model of autism. Mol Psychiatry 2021; 26:7582-7595. [PMID: 34290367 PMCID: PMC8872977 DOI: 10.1038/s41380-021-01227-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 02/06/2023]
Abstract
Oxytocin is an important regulator of the social brain. In some animal models of autism, notably in Magel2tm1.1Mus-deficient mice, peripheral administration of oxytocin in infancy improves social behaviors until adulthood. However, neither the mechanisms responsible for social deficits nor the mechanisms by which such oxytocin administration has long-term effects are known. Here, we aimed to clarify these oxytocin-dependent mechanisms, focusing on social memory performance. Using in situ hybridization (RNAscope), we have established that Magel2 and oxytocin receptor are co-expressed in the dentate gyrus and CA2/CA3 hippocampal regions involved in the circuitry underlying social memory. Then, we have shown that Magel2tm1.1Mus-deficient mice, evaluated in a three-chamber test, present a deficit in social memory. Next, in hippocampus, we conducted neuroanatomical and functional studies using immunostaining, oxytocin-binding experiments, ex vivo electrophysiological recordings, calcium imaging and biochemical studies. We demonstrated: an increase of the GABAergic activity of CA3-pyramidal cells associated with an increase in the quantity of oxytocin receptors and of somatostatin interneurons in both DG and CA2/CA3 regions. We also revealed a delay in the GABAergic development sequence in Magel2tm1.1Mus-deficient pups, linked to phosphorylation modifications of KCC2. Above all, we demonstrated the positive effects of subcutaneous administration of oxytocin in the mutant neonates, restoring hippocampal alterations and social memory at adulthood. Although clinical trials are debated, this study highlights the mechanisms by which peripheral oxytocin administration in neonates impacts the brain and demonstrates the therapeutic value of oxytocin to treat infants with autism spectrum disorders.
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Affiliation(s)
- Alessandra Bertoni
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Fabienne Schaller
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Roman Tyzio
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | | | - Francesca Santini
- Institute of Neuroscience, National Research Council (CNR), Vedano al Lambro, Italy. Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Marion Xolin
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Diabé Diabira
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | | | - Valery Matarazzo
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Igor Medina
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | | | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, College of Medicine and Health, Hatherly Laboratories, University of Exeter, Exeter, UK
| | - Bice Chini
- Institute of Neuroscience, National Research Council (CNR), Vedano al Lambro, Italy. NeuroMI Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
| | - Jean-Luc Gaiarsa
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
| | - Françoise Muscatelli
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1249, Institut de Neurobiologie de la Méditerranée (INMED), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France.
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42
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Contractor A, Ethell IM, Portera-Cailliau C. Cortical interneurons in autism. Nat Neurosci 2021; 24:1648-1659. [PMID: 34848882 PMCID: PMC9798607 DOI: 10.1038/s41593-021-00967-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 09/21/2021] [Indexed: 01/01/2023]
Abstract
The mechanistic underpinnings of autism remain a subject of debate and controversy. Why do individuals with autism share an overlapping set of atypical behaviors and symptoms, despite having different genetic and environmental risk factors? A major challenge in developing new therapies for autism has been the inability to identify convergent neural phenotypes that could explain the common set of symptoms that result in the diagnosis. Although no striking macroscopic neuropathological changes have been identified in autism, there is growing evidence that inhibitory interneurons (INs) play an important role in its neural basis. In this Review, we evaluate and interpret this evidence, focusing on recent findings showing reduced density and activity of the parvalbumin class of INs. We discuss the need for additional studies that investigate how genes and the environment interact to change the developmental trajectory of INs, permanently altering their numbers, connectivity and circuit engagement.
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Affiliation(s)
- Anis Contractor
- Department of Neuroscience Feinberg School of Medicine, Weinberg College of Arts and Sciences, Northwestern University, Chicago, IL, USA
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Chicago, IL, USA
| | - Iryna M Ethell
- Division of Biomedical Sciences, UC Riverside School of Medicine, Riverside, CA, USA
| | - Carlos Portera-Cailliau
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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43
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Vallés AS, Barrantes FJ. Dysregulation of Neuronal Nicotinic Acetylcholine Receptor-Cholesterol Crosstalk in Autism Spectrum Disorder. Front Mol Neurosci 2021; 14:744597. [PMID: 34803605 PMCID: PMC8604044 DOI: 10.3389/fnmol.2021.744597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/21/2021] [Indexed: 12/27/2022] Open
Abstract
Autism spectrum disorder (ASD) is a set of complex neurodevelopmental diseases that include impaired social interaction, delayed and disordered language, repetitive or stereotypic behavior, restricted range of interests, and altered sensory processing. The underlying causes of the core symptoms remain unclear, as are the factors that trigger their onset. Given the complexity and heterogeneity of the clinical phenotypes, a constellation of genetic, epigenetic, environmental, and immunological factors may be involved. The lack of appropriate biomarkers for the evaluation of neurodevelopmental disorders makes it difficult to assess the contribution of early alterations in neurochemical processes and neuroanatomical and neurodevelopmental factors to ASD. Abnormalities in the cholinergic system in various regions of the brain and cerebellum are observed in ASD, and recently altered cholesterol metabolism has been implicated at the initial stages of the disease. Given the multiple effects of the neutral lipid cholesterol on the paradigm rapid ligand-gated ion channel, the nicotinic acetylcholine receptor, we explore in this review the possibility that the dysregulation of nicotinic receptor-cholesterol crosstalk plays a role in some of the neurological alterations observed in ASD.
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Affiliation(s)
- Ana Sofía Vallés
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (UNS-CONICET), Buenos Aires, Argentina
| | - Francisco J Barrantes
- Instituto de Investigaciones Biomédicas (BIOMED), UCA-CONICET, Buenos Aires, Argentina
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Gigliucci V, Teutsch J, Woodbury-Smith M, Luoni M, Busnelli M, Chini B, Banerjee A. Region-Specific KCC2 Rescue by rhIGF-1 and Oxytocin in a Mouse Model of Rett Syndrome. Cereb Cortex 2021; 32:2885-2894. [PMID: 34791112 DOI: 10.1093/cercor/bhab388] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 01/17/2023] Open
Abstract
Rett syndrome (RTT) is characterized by dysfunction in neuronal excitation/inhibition (E/I) balance, potentially impacting seizure susceptibility via deficits in K+/Cl- cotransporter 2 (KCC2) function. Mice lacking the Methyl-CpG binding protein 2 (MeCP2) recapitulate many symptoms of RTT, and recombinant human insulin-like growth factor-1 (rhIGF-1) restores KCC2 expression and E/I balance in MeCP2 KO mice. However, clinical trial outcomes of rhIGF-1 in RTT have been variable, and increasing its therapeutic efficacy is highly desirable. To this end, the neuropeptide oxytocin (OXT) is promising, as it also critically modulates KCC2 function during early postnatal development. We measured basal KCC2 expression levels in MeCP2 KO mice and identified 3 key frontal brain regions showing KCC2 alterations in young adult mice, but not in postnatal P10 animals. We hypothesized that deficits in an IGF-1/OXT signaling crosstalk modulating KCC2 may occur in RTT during postnatal development. Consistently, we detected alterations of IGF-1 receptor and OXT receptor levels in those brain areas. rhIGF-1 and OXT treatments in KO mice rescued KCC2 expression in a region-specific and complementary manner. These results suggest that region-selective combinatorial pharmacotherapeutic strategies could be most effective at normalizing E/I balance in key brain regions subtending the RTT pathophysiology.
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Affiliation(s)
| | - Jasper Teutsch
- Neuroscience Theme, Biosciences Institute, Newcastle University, United Kingdom.,Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Marc Woodbury-Smith
- Neuroscience Theme, Biosciences Institute, Newcastle University, United Kingdom
| | - Mirko Luoni
- Stem Cells and Neurogenesis Unit, San Raffaele Scientific Institute, Milan, Italy
| | - Marta Busnelli
- Institute of Neuroscience, CNR, Milan, Italy.,NeuroMi Milan Center for Neuroscience, Milan, Italy
| | - Bice Chini
- Institute of Neuroscience, CNR, Milan, Italy.,NeuroMi Milan Center for Neuroscience, Milan, Italy
| | - Abhishek Banerjee
- Neuroscience Theme, Biosciences Institute, Newcastle University, United Kingdom.,Brain Research Institute, University of Zurich, Zurich, Switzerland
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Verma V, Kumar MJV, Sharma K, Rajaram S, Muddashetty R, Manjithaya R, Behnisch T, Clement JP. Pharmacological intervention in young adolescents rescues synaptic physiology and behavioural deficits in Syngap1 +/- mice. Exp Brain Res 2021; 240:289-309. [PMID: 34739555 DOI: 10.1007/s00221-021-06254-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 10/21/2021] [Indexed: 01/04/2023]
Abstract
Haploinsufficiency in SYNGAP1 is implicated in intellectual disability (ID) and autism spectrum disorder (ASD) and affects the maturation of dendritic spines. The abnormal spine development has been suggested to cause a disbalance of excitatory and inhibitory (E/I) neurotransmission at distinct developmental periods. In addition, E/I imbalances in Syngap1+/- mice might be due to abnormalities in K+-Cl- co-transporter function (NKCC1, KCC2), in a maner similar to the murine models of Fragile-X and Rett syndromes. To study whether an altered intracellular chloride ion concentration represents an underlying mechanism of modified function of GABAergic synapses in Dentate Gyrus Granule Cells of Syngap1+/- recordings were performed at different developmental stages of the mice. We observed depolarised neurons at P14-15 as illustrated by decreased Cl- reversal potential in Syngap1+/- mice. The KCC2 expression was decreased compared to Wild-type (WT) mice at P14-15. The GSK-3β inhibitor, 6-bromoindirubin-3'-oxime (6BIO) that crosses the blood-brain barrier, was tested to restore the function of GABAergic synapses. We discovered that the intraperitoneal administration of 6BIO during the critical period or young adolescents [P30 to P80 (4-week to 10-week)] normalised an altered E/I balance, the deficits of synaptic plasticity, and behavioural performance like social novelty, anxiety, and memory of the Syngap1+/- mice. In summary, altered GABAergic function in Syngap1+/- mice is due to reduced KCC2 expression leading to an increase in the intracellular chloride concentration that can be counteracted by the 6BIO, which restored cognitive, emotional, and social symptoms by pharmacological intervention, particularly in adulthood.
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Affiliation(s)
- Vijaya Verma
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - M J Vijay Kumar
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Kavita Sharma
- International Centre for Material Sciences, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Sridhar Rajaram
- International Centre for Material Sciences, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Ravi Muddashetty
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, 560065, India
| | - Ravi Manjithaya
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.,Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Thomas Behnisch
- Institutes of Brain Sciences, Fudan University, Shanghai, 200032, China
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.
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Collapse of complexity of brain and body activity due to excessive inhibition and MeCP2 disruption. Proc Natl Acad Sci U S A 2021; 118:2106378118. [PMID: 34686597 DOI: 10.1073/pnas.2106378118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2021] [Indexed: 11/18/2022] Open
Abstract
Complex body movements require complex dynamics and coordination among neurons in motor cortex. Conversely, a long-standing theoretical notion supposes that if many neurons in motor cortex become excessively synchronized, they may lack the necessary complexity for healthy motor coding. However, direct experimental support for this idea is rare and underlying mechanisms are unclear. Here we recorded three-dimensional body movements and spiking activity of many single neurons in motor cortex of rats with enhanced synaptic inhibition and a transgenic rat model of Rett syndrome (RTT). For both cases, we found a collapse of complexity in the motor system. Reduced complexity was apparent in lower-dimensional, stereotyped brain-body interactions, neural synchrony, and simpler behavior. Our results demonstrate how imbalanced inhibition can cause excessive synchrony among movement-related neurons and, consequently, a stereotyped motor code. Excessive inhibition and synchrony may underlie abnormal motor function in RTT.
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Savardi A, Borgogno M, De Vivo M, Cancedda L. Pharmacological tools to target NKCC1 in brain disorders. Trends Pharmacol Sci 2021; 42:1009-1034. [PMID: 34620512 DOI: 10.1016/j.tips.2021.09.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/27/2021] [Accepted: 09/08/2021] [Indexed: 02/06/2023]
Abstract
The chloride importer NKCC1 and the chloride exporter KCC2 are key regulators of neuronal chloride concentration. A defective NKCC1/KCC2 expression ratio is associated with several brain disorders. Preclinical/clinical studies have shown that NKCC1 inhibition by the United States FDA-approved diuretic bumetanide is a potential therapeutic strategy in preclinical/clinical studies of multiple neurological conditions. However, bumetanide has poor brain penetration and causes unwanted diuresis by inhibiting NKCC2 in the kidney. To overcome these issues, a growing number of studies have reported more brain-penetrating and/or selective bumetanide prodrugs, analogs, and new molecular entities. Here, we review the evidence for NKCC1 pharmacological inhibition as an effective strategy to manage neurological disorders. We also discuss the advantages and limitations of bumetanide repurposing and the benefits and risks of new NKCC1 inhibitors as therapeutic agents for brain disorders.
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Affiliation(s)
- Annalisa Savardi
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genoa, Italy; Dulbecco Telethon Institute, 00185 Rome, Italy; Molecular Modeling and Drug Discovery Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genoa, Italy
| | - Marco Borgogno
- Molecular Modeling and Drug Discovery Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genoa, Italy
| | - Marco De Vivo
- Molecular Modeling and Drug Discovery Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genoa, Italy.
| | - Laura Cancedda
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genoa, Italy; Dulbecco Telethon Institute, 00185 Rome, Italy.
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48
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A O, U M, Lf B, A GC. Energy metabolism in childhood neurodevelopmental disorders. EBioMedicine 2021; 69:103474. [PMID: 34256347 PMCID: PMC8324816 DOI: 10.1016/j.ebiom.2021.103474] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/30/2021] [Accepted: 06/18/2021] [Indexed: 12/24/2022] Open
Abstract
Whereas energy function in the aging brain and their related neurodegenerative diseases has been explored in some detail, there is limited knowledge about molecular mechanisms and brain networks of energy metabolism during infancy and childhood. In this review we describe current insights on physiological brain energetics at prenatal and neonatal stages, and in childhood. We then describe the main groups of inborn errors of energy metabolism affecting the brain. Of note, scarce basic neuroscience research in this field limits the opportunity for these disorders to provide paradigms of energy utilization during neurodevelopment. Finally, we report energy metabolism disturbances in well-known non-metabolic neurodevelopmental disorders. As energy metabolism is a fundamental biological function, brain energy utilization is likely altered in most neuropediatric diseases. Precise knowledge on mechanisms of brain energy disturbance will open the possibility of metabolic modulation therapies regardless of disease etiology.
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Affiliation(s)
- Oyarzábal A
- Neurometabolic Unit and Laboratory of Synaptic Metabolism. IPR, CIBERER (ISCIII) and MetabERN, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Musokhranova U
- Neurometabolic Unit and Laboratory of Synaptic Metabolism. IPR, CIBERER (ISCIII) and MetabERN, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Barros Lf
- Center for Scientific Studies - CECs, Valdivia 5110466, Chile
| | - García-Cazorla A
- Neurometabolic Unit and Laboratory of Synaptic Metabolism. IPR, CIBERER (ISCIII) and MetabERN, Hospital Sant Joan de Déu, Barcelona, Spain.
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49
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Martynyuk AE, Ju LS, Morey TE. The potential role of stress and sex steroids in heritable effects of sevoflurane. Biol Reprod 2021; 105:735-746. [PMID: 34192761 DOI: 10.1093/biolre/ioab129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/17/2021] [Accepted: 06/25/2021] [Indexed: 12/11/2022] Open
Abstract
Most surgical procedures require general anesthesia, which is a reversible deep sedation state lacking all perception. The induction of this state is possible because of complex molecular and neuronal network actions of general anesthetics (GAs) and other pharmacological agents. Laboratory and clinical studies indicate that the effects of GAs may not be completely reversible upon anesthesia withdrawal. The long-term neurocognitive effects of GAs, especially when administered at the extremes of ages, are an increasingly recognized health concern and the subject of extensive laboratory and clinical research. Initial studies in rodents suggest that the adverse effects of GAs, whose actions involve enhancement of GABA type A receptor activity (GABAergic GAs), can also extend to future unexposed offspring. Importantly, experimental findings show that GABAergic GAs may induce heritable effects when administered from the early postnatal period to at least young adulthood, covering nearly all age groups that may have children after exposure to anesthesia. More studies are needed to understand when and how the clinical use of GAs in a large and growing population of patients can result in lower resilience to diseases in the even larger population of their unexposed offspring. This minireview is focused on the authors' published results and data in the literature supporting the notion that GABAergic GAs, in particular sevoflurane, may upregulate systemic levels of stress and sex steroids and alter expressions of genes that are essential for the functioning of these steroid systems. The authors hypothesize that stress and sex steroids are involved in the mediation of sex-specific heritable effects of sevoflurane.
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Affiliation(s)
- Anatoly E Martynyuk
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA.,McKnight Brain Institute, University of Florida College of Medicine, Gainesville, FL, USA
| | - Ling-Sha Ju
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Timothy E Morey
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA
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Del Rosario J, Speed A, Arrowood H, Motz C, Pardue M, Haider B. Diminished Cortical Excitation and Elevated Inhibition During Perceptual Impairments in a Mouse Model of Autism. Cereb Cortex 2021; 31:3462-3474. [PMID: 33677512 PMCID: PMC8525192 DOI: 10.1093/cercor/bhab025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 01/14/2021] [Accepted: 01/21/2021] [Indexed: 01/02/2023] Open
Abstract
Sensory impairments are a core feature of autism spectrum disorder (ASD). These impairments affect visual perception and have been hypothesized to arise from imbalances in cortical excitatory and inhibitory activity. There is conflicting evidence for this hypothesis from several recent studies of transgenic mouse models of ASD; crucially, none have measured activity from identified excitatory and inhibitory neurons during simultaneous impairments of sensory perception. Here, we directly recorded putative excitatory and inhibitory population spiking in primary visual cortex (V1) while simultaneously measuring visual perceptual behavior in CNTNAP2-/- knockout (KO) mice. We observed quantitative impairments in the speed, accuracy, and contrast sensitivity of visual perception in KO mice. During these perceptual impairments, stimuli evoked more firing of inhibitory neurons and less firing of excitatory neurons, with reduced neural sensitivity to contrast. In addition, pervasive 3-10 Hz oscillations in superficial cortical layers 2/3 (L2/3) of KO mice degraded predictions of behavioral performance from neural activity. Our findings show that perceptual deficits relevant to ASD may be associated with elevated cortical inhibitory activity along with diminished and aberrant excitatory population activity in L2/3, a major source of feedforward projections to higher cortical regions.
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Affiliation(s)
- Joseph Del Rosario
- Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA
| | - Anderson Speed
- Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA
| | - Hayley Arrowood
- Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA
| | - Cara Motz
- Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA
- Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur, GA 30033, USA
| | - Machelle Pardue
- Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA
- Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur, GA 30033, USA
| | - Bilal Haider
- Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA
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