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Reynolds KE, Huang E, Sabbineni M, Wiseman E, Murtaza N, Ahuja D, Napier M, Murphy KM, Singh KK, Scott AL. Purinergic Signalling Mediates Aberrant Excitability of Developing Neuronal Circuits in the Fmr1 Knockout Mouse Model. Mol Neurobiol 2024:10.1007/s12035-024-04181-w. [PMID: 38652351 DOI: 10.1007/s12035-024-04181-w] [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: 12/06/2023] [Accepted: 04/15/2024] [Indexed: 04/25/2024]
Abstract
Neuronal hyperexcitability within developing cortical circuits is a common characteristic of several heritable neurodevelopmental disorders, including Fragile X Syndrome (FXS), intellectual disability and autism spectrum disorders (ASD). While this aberrant circuitry is typically studied from a neuron-centric perspective, glial cells secrete soluble factors that regulate both neurite extension and synaptogenesis during development. The nucleotide-mediated purinergic signalling system is particularly instrumental in facilitating these effects. We recently reported that within a FXS animal model, the Fmr1 KO mouse, the purinergic signalling system is upregulated in cortical astrocytes leading to altered secretion of synaptogenic and plasticity-related proteins. In this study, we examined whether elevated astrocyte purinergic signalling also impacts neuronal morphology and connectivity of Fmr1 KO cortical neurons. Here, we found that conditioned media from primary Fmr1 KO astrocytes was sufficient to enhance neurite extension and complexity of both wildtype and Fmr1 KO neurons to a similar degree as UTP-mediated outgrowth. Significantly enhanced firing was also observed in Fmr1 KO neuron-astrocyte co-cultures grown on microelectrode arrays but was associated with large deficits in firing synchrony. The selective P2Y2 purinergic receptor antagonist AR-C 118925XX effectively normalized much of the aberrant Fmr1 KO activity, designating P2Y2 as a potential therapeutic target in FXS. These results not only demonstrate the importance of astrocyte soluble factors in the development of neural circuitry, but also show that P2Y purinergic receptors play a distinct role in pathological FXS neuronal activity.
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Affiliation(s)
- Kathryn E Reynolds
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Eileen Huang
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Monica Sabbineni
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Eliza Wiseman
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Nadeem Murtaza
- McMaster Stem Cell and Cancer Research Institute, McMaster University, Hamilton, ON, Canada
| | - Desmond Ahuja
- Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON, Canada
| | - Matt Napier
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
- Department of Molecular and Cellular Biology, University of Guelph, 488 Gordon St, Guelph, ON, Canada
| | - Kathryn M Murphy
- Department of Psychology, Neuroscience, and Behaviour, McMaster University, Hamilton, ON, Canada
| | | | - Angela L Scott
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
- Department of Molecular and Cellular Biology, University of Guelph, 488 Gordon St, Guelph, ON, Canada.
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Kuruppath P, Xue L, Pouille F, Jones ST, Schoppa NE. Hyperexcitability in the Olfactory Bulb and Impaired Fine Odor Discrimination in the Fmr1 KO Mouse Model of Fragile X Syndrome. J Neurosci 2023; 43:8243-8258. [PMID: 37788940 PMCID: PMC10697393 DOI: 10.1523/jneurosci.0584-23.2023] [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: 03/29/2023] [Revised: 08/28/2023] [Accepted: 09/23/2023] [Indexed: 10/05/2023] Open
Abstract
Fragile X syndrome (FXS) is the single most common monogenetic cause of autism spectrum disorders (ASDs) in humans. FXS is caused by loss of expression of the fragile X mental retardation protein (FMRP), an mRNA-binding protein encoded on the X chromosome involved in suppressing protein translation. Sensory processing deficits have been a major focus of studies of FXS in both humans and rodent models of FXS, but olfactory deficits remain poorly understood. Here, we conducted experiments in wild-type (WT) and Fmr1 knock-out (KO; Fmr1-/y ) mice (males) that lack expression of the gene encoding FMRP to assess olfactory circuit and behavioral abnormalities. In patch-clamp recordings conducted in slices of the olfactory bulb, output mitral cells (MCs) in Fmr1 KO mice displayed greatly enhanced excitation under baseline conditions, as evidenced by a much higher rate of occurrence of spontaneous network-level events known as long-lasting depolarizations (LLDs). The higher probability of spontaneous LLDs (sLLDs), which appeared to be because of a decrease in GABAergic synaptic inhibition in glomeruli leading to more feedforward excitation, caused a reduction in the reliability of stimulation-evoked responses in MCs. In addition, in a go/no-go operant discrimination paradigm, we found that Fmr1 KO mice displayed impaired discrimination of odors in difficult tasks that involved odor mixtures but not altered discrimination of monomolecular odors. We suggest that the Fmr1 KO-induced reduction in MC response reliability is one plausible mechanism for the impaired fine odor discrimination.SIGNIFICANCE STATEMENT Fragile X syndrome (FXS) in humans is associated with a range of debilitating deficits including aberrant sensory processing. One sensory system that has received comparatively little attention in studies in animal models of FXS is olfaction. Here, we report the first comprehensive physiological analysis of circuit defects in the olfactory bulb in the commonly-used Fmr1 knock-out (KO) mouse model of FXS. Our studies indicate that Fmr1 KO alters the local excitation/inhibition balance in the bulb, similar to what Fmr1 KO does in other brain circuits, but through a novel mechanism that involves enhanced feedforward excitation. Furthermore, Fmr1 KO mice display behavioral impairments in fine odor discrimination, an effect that may be explained by changes in neural response reliability.
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Affiliation(s)
- Praveen Kuruppath
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Lin Xue
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Frederic Pouille
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Shelly T Jones
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Nathan E Schoppa
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
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Milla LA, Corral L, Rivera J, Zuñiga N, Pino G, Nunez-Parra A, Cea-Del Rio CA. Neurodevelopment and early pharmacological interventions in Fragile X Syndrome. Front Neurosci 2023; 17:1213410. [PMID: 37599992 PMCID: PMC10433175 DOI: 10.3389/fnins.2023.1213410] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Fragile X Syndrome (FXS) is a neurodevelopmental disorder and the leading monogenic cause of autism and intellectual disability. For years, several efforts have been made to develop an effective therapeutic approach to phenotypically rescue patients from the disorder, with some even advancing to late phases of clinical trials. Unfortunately, none of these attempts have completely succeeded, bringing urgency to further expand and refocus research on FXS therapeutics. FXS arises at early stages of postnatal development due to the mutation and transcriptional silencing of the Fragile X Messenger Ribonucleoprotein 1 gene (FMR1) and consequent loss of the Fragile X Messenger Ribonucleoprotein (FMRP) expression. Importantly, FMRP expression is critical for the normal adult nervous system function, particularly during specific windows of embryogenic and early postnatal development. Cellular proliferation, migration, morphology, axonal guidance, synapse formation, and in general, neuronal network establishment and maturation are abnormally regulated in FXS, underlying the cognitive and behavioral phenotypes of the disorder. In this review, we highlight the relevance of therapeutically intervening during critical time points of development, such as early postnatal periods in infants and young children and discuss past and current clinical trials in FXS and their potential to specifically target those periods. We also discuss potential benefits, limitations, and disadvantages of these pharmacological tools based on preclinical and clinical research.
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Affiliation(s)
- Luis A. Milla
- Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Lucia Corral
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Jhanpool Rivera
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Nolberto Zuñiga
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Gabriela Pino
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Alexia Nunez-Parra
- Physiology Laboratory, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile
- Cell Physiology Center, Universidad de Chile, Santiago, Chile
| | - Christian A. Cea-Del Rio
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
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Woods R, Lorusso J, Fletcher J, ElTaher H, McEwan F, Harris I, Kowash H, D'Souza SW, Harte M, Hager R, Glazier JD. Maternal immune activation and role of placenta in the prenatal programming of neurodevelopmental disorders. Neuronal Signal 2023; 7:NS20220064. [PMID: 37332846 PMCID: PMC10273029 DOI: 10.1042/ns20220064] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023] Open
Abstract
Maternal infection during pregnancy, leading to maternal immune activation (mIA) and cytokine release, increases the offspring risk of developing a variety of neurodevelopmental disorders (NDDs), including schizophrenia. Animal models have provided evidence to support these mechanistic links, with placental inflammatory responses and dysregulation of placental function implicated. This leads to changes in fetal brain cytokine balance and altered epigenetic regulation of key neurodevelopmental pathways. The prenatal timing of such mIA-evoked changes, and the accompanying fetal developmental responses to an altered in utero environment, will determine the scope of the impacts on neurodevelopmental processes. Such dysregulation can impart enduring neuropathological changes, which manifest subsequently in the postnatal period as altered neurodevelopmental behaviours in the offspring. Hence, elucidation of the functional changes that occur at the molecular level in the placenta is vital in improving our understanding of the mechanisms that underlie the pathogenesis of NDDs. This has notable relevance to the recent COVID-19 pandemic, where inflammatory responses in the placenta to SARS-CoV-2 infection during pregnancy and NDDs in early childhood have been reported. This review presents an integrated overview of these collective topics and describes the possible contribution of prenatal programming through placental effects as an underlying mechanism that links to NDD risk, underpinned by altered epigenetic regulation of neurodevelopmental pathways.
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Affiliation(s)
- Rebecca M. Woods
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
| | - Jarred M. Lorusso
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
| | - Jennifer Fletcher
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Medicine, Biology and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
| | - Heidi ElTaher
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Medicine, Biology and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
- Department of Physiology, Faculty of Medicine, Alexandria University, Egypt
| | - Francesca McEwan
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
| | - Isabella Harris
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
| | - Hager M. Kowash
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9WL, U.K
| | - Stephen W. D'Souza
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9WL, U.K
| | - Michael Harte
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Medicine, Biology and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
| | - Reinmar Hager
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
| | - Jocelyn D. Glazier
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, U.K
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Hostetler RE, Hu H, Agmon A. Genetically Defined Subtypes of Somatostatin-Containing Cortical Interneurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.02.526850. [PMID: 36778499 PMCID: PMC9915678 DOI: 10.1101/2023.02.02.526850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
UNLABELLED Inhibitory interneurons play a crucial role in proper development and function of the mammalian cerebral cortex. Of the different inhibitory subclasses, dendritic-targeting, somatostatin-containing (SOM) interneurons may be the most diverse. Earlier studies used transgenic mouse lines to identify and characterize subtypes of SOM interneurons by morphological, electrophysiological and neurochemical properties. More recently, large-scale studies classified SOM interneurons into 13 morpho-electro-transcriptomic (MET) types. It remains unclear, however, how these various classification schemes relate to each other, and experimental access to MET types has been limited by the scarcity of type-specific mouse driver lines. To begin to address these issues we crossed Flp and Cre driver mouse lines and a dual-color combinatorial reporter, allowing experimental access to genetically defined SOM subsets. Brains from adult mice of both sexes were retrogradely dye-labeled from the pial surface to identify layer 1-projecting neurons, and immunostained against several marker proteins, allowing correlation of genetic label, axonal target and marker protein expression in the same neurons. Using whole-cell recordings ex-vivo, we compared electrophysiological properties between intersectional and transgenic SOM subsets. We identified two layer 1-targeting intersectional subsets with non-overlapping marker protein expression and electrophysiological properties which, together with a previously characterized layer 4-targeting subtype, account for about half of all layer 5 SOM cells and >40% of all SOM cells, and appear to map onto 5 of the 13 MET types. Genetic access to these subtypes will allow researchers to determine their synaptic inputs and outputs and uncover their roles in cortical computations and animal behavior. SIGNIFICANCE STATEMENT Inhibitory neurons are critically important for proper development and function of the cerebral cortex. Although a minority population, they are highly diverse, which poses a major challenge to investigating their contributions to cortical computations and animal and human behavior. As a step towards understanding this diversity we crossed genetically modified mouse lines to allow detailed examination of genetically-defined groups of the most diverse inhibitory subtype, somatostatin-containing interneurons. We identified and characterized three somatostatin subtypes in the deep cortical layers with distinct combinations of anatomical, neurochemical and electrophysiological properties. Future studies could now use these genetic tools to examine how these different subtypes are integrated into the cortical circuit and what roles they play during sensory, cognitive or motor behavior.
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Affiliation(s)
- Rachel E Hostetler
- Dept. of Neuroscience, West Virginia University School of Medicine, WV Rockefeller Neuroscience Institute, Morgantown, WV 26506, USA
| | - Hang Hu
- Dept. of Neuroscience, West Virginia University School of Medicine, WV Rockefeller Neuroscience Institute, Morgantown, WV 26506, USA
| | - Ariel Agmon
- Dept. of Neuroscience, West Virginia University School of Medicine, WV Rockefeller Neuroscience Institute, Morgantown, WV 26506, USA
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6
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Svalina MN, Sullivan R, Restrepo D, Huntsman MM. From circuits to behavior: Amygdala dysfunction in fragile X syndrome. Front Integr Neurosci 2023; 17:1128529. [PMID: 36969493 PMCID: PMC10034113 DOI: 10.3389/fnint.2023.1128529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/23/2023] [Indexed: 03/12/2023] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by a repeat expansion mutation in the promotor region of the FMR1 gene resulting in transcriptional silencing and loss of function of fragile X messenger ribonucleoprotein 1 protein (FMRP). FMRP has a well-defined role in the early development of the brain. Thus, loss of the FMRP has well-known consequences for normal cellular and synaptic development leading to a variety of neuropsychiatric disorders including an increased prevalence of amygdala-based disorders. Despite our detailed understanding of the pathophysiology of FXS, the precise cellular and circuit-level underpinnings of amygdala-based disorders is incompletely understood. In this review, we discuss the development of the amygdala, the role of neuromodulation in the critical period plasticity, and recent advances in our understanding of how synaptic and circuit-level changes in the basolateral amygdala contribute to the behavioral manifestations seen in FXS.
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Affiliation(s)
- Matthew N. Svalina
- Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Regina Sullivan
- Brain Institute, Nathan Kline Institute, Orangeburg, NY, United States
- Child and Adolescent Psychiatry, Child Study Center, New York University School of Medicine, New York, NY, United States
| | - Diego Restrepo
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Molly M. Huntsman
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- *Correspondence: Molly M. Huntsman,
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7
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Zhu SI, McCullough MH, Pujic Z, Sibberas J, Sun B, Darveniza T, Bucknall B, Avitan L, Goodhill GJ. fmr1 Mutation Alters the Early Development of Sensory Coding and Hunting and Social Behaviors in Larval Zebrafish. J Neurosci 2023; 43:1211-1224. [PMID: 36596699 PMCID: PMC9962781 DOI: 10.1523/jneurosci.1721-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 01/05/2023] Open
Abstract
Autism spectrum disorders (ASDs) are developmental in origin; however, little is known about how they affect the early development of behavior and sensory coding. The most common inherited form of autism is Fragile X syndrome (FXS), caused by a mutation in FMR1 Mutation of fmr1 in zebrafish causes anxiety-like behavior, hyperactivity, and hypersensitivity in auditory and visual processing. Here, we show that zebrafish fmr1-/- mutant larvae of either sex also display changes in hunting behavior, tectal coding, and social interaction. During hunting, they were less successful at catching prey and displayed altered behavioral sequences. In the tectum, representations of prey-like stimuli were more diffuse and had higher dimensionality. In a social behavioral assay, they spent more time observing a conspecific but responded more slowly to social cues. However, when given a choice of rearing environment fmr1-/- larvae preferred one with reduced visual stimulation, and rearing them in this environment reduced genotype-specific effects on tectal excitability. Together, these results shed new light on how fmr1-/- changes the early development of neural systems and behavior in a vertebrate.SIGNIFICANCE STATEMENT Autism spectrum disorders (ASDs) are caused by changes in early neural development. Animal models of ASDs offer the opportunity to study these developmental processes in greater detail than in humans. Here, we found that a zebrafish mutant for a gene which in humans causes one type of ASD showed early alterations in hunting behavior, social behavior, and how visual stimuli are represented in the brain. However, we also found that mutant fish preferred reduced visual stimulation, and rearing them in this environment reduced alterations in neural activity patterns. These results suggest interesting new directions for using zebrafish as a model to study the development of brain and behavior in ASDs, and how the impact of ASDs could potentially be reduced.
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Affiliation(s)
- Shuyu I Zhu
- Queensland Brain Institute
- Departments of Developmental Biology and Neuroscience, Washington University in St. Louis, St. Louis, Missouri 63110
| | | | | | | | | | - Thomas Darveniza
- Departments of Developmental Biology and Neuroscience, Washington University in St. Louis, St. Louis, Missouri 63110
| | | | | | - Geoffrey J Goodhill
- Queensland Brain Institute
- School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia
- Departments of Developmental Biology and Neuroscience, Washington University in St. Louis, St. Louis, Missouri 63110
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8
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Kalyanasundar B, Blonde GD, Spector AC, Travers SP. A Novel Mechanism for T1R-Independent Taste Responses to Concentrated Sugars. J Neurosci 2023; 43:965-978. [PMID: 36623875 PMCID: PMC9908317 DOI: 10.1523/jneurosci.1760-22.2023] [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: 09/15/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Recent findings from our laboratory demonstrated that the rostral nucleus of the solitary tract (rNST) retains some responsiveness to sugars in double-knock-out mice lacking either the T1R1+T1R3 (KO1+3) or T1R2+T1R3 (KO2+3) taste receptor heterodimers. Here, we extended these findings in the parabrachial nucleus (PBN) of male and female KO1+3 mice using warm stimuli to optimize sugar responses and employing additional concentrations and pharmacological agents to probe mechanisms. PBN T1R-independent sugar responses, including those to concentrated glucose, were more evident than in rNST. Similar to the NST, there were no "sugar-best" neurons in KO1+3 mice. Nevertheless, 1000 mm glucose activated nearly 55% of PBN neurons, with responses usually occurring in neurons that also displayed acid and amiloride-insensitive NaCl responses. In wild-type (WT) mice, concentrated sugars activated the same electrolyte-sensitive neurons but also "sugar-best" cells. Regardless of genotype, phlorizin, an inhibitor of the sodium-glucose co-transporter (SGLT), a component of a hypothesized alternate glucose-sensing mechanism, did not diminish responses to 1000 mm glucose. The efficacy of concentrated sugars for driving neurons broadly responsive to electrolytes implied an origin from Type III taste bud cells. To test this, we used the carbonic anhydrase (CA) inhibitor dorzolamide (DRZ), previously shown to inhibit amiloride-insensitive sodium responses arising from Type III taste bud cells. Dorzolamide had no effect on sugar-elicited responses in WT sugar-best PBN neurons but strongly suppressed them in WT and KO1+3 electrolyte-generalist neurons. These findings suggest a novel T1R-independent mechanism for hyperosmotic sugars, involving a CA-dependent mechanism in Type III taste bud cells.SIGNIFICANCE STATEMENT Since the discovery of Tas1r receptors for sugars and artificial sweeteners, evidence has accrued that mice lacking these receptors maintain some behavioral, physiological, and neural responsiveness to sugars. But the substrate(s) has remained elusive. Here, we recorded from parabrachial nucleus (PBN) taste neurons and identified T1R-independent responses to hyperosmotic sugars dependent on carbonic anhydrase (CA) and occurring primarily in neurons broadly responsive to NaCl and acid, implying an origin from Type III taste bud cells. The effectiveness of different sugars in driving these T1R-independent responses did not correlate with their efficacy in driving licking, suggesting they evoke a nonsweet sensation. Nevertheless, these salient responses are likely to comprise an adequate cue for learned preferences that occur in the absence of T1R receptors.
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Affiliation(s)
- B Kalyanasundar
- Division of Biosciences, College of Dentistry, Ohio State University, Columbus, Ohio, 43210-1267
| | - Ginger D Blonde
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida, 32306-4301
| | - Alan C Spector
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida, 32306-4301
| | - Susan P Travers
- Division of Biosciences, College of Dentistry, Ohio State University, Columbus, Ohio, 43210-1267
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Svalina MN, Rio CACD, Kushner JK, Levy A, Baca SM, Guthman EM, Opendak M, Sullivan RM, Restrepo D, Huntsman MM. Basolateral Amygdala Hyperexcitability Is Associated with Precocious Developmental Emergence of Fear-Learning in Fragile X Syndrome. J Neurosci 2022; 42:7294-7308. [PMID: 35970562 PMCID: PMC9512574 DOI: 10.1523/jneurosci.1776-21.2022] [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: 09/01/2021] [Revised: 08/02/2022] [Accepted: 08/05/2022] [Indexed: 12/24/2022] Open
Abstract
Fragile X Syndrome is a neurodevelopmental disorder and the most common monogenic cause of intellectual disability, autism spectrum disorders, and anxiety disorders. Loss of fragile x mental retardation protein results in disruptions of synaptic development during a critical period of circuit formation in the BLA. However, it is unknown how these alterations impact microcircuit development and function. Using a combination of electrophysiologic and behavioral approaches in both male (Fmr1-/y) and female (Fmr1-/-) mice, we demonstrate that principal neurons in the Fmr1KO BLA exhibit hyperexcitability during a sensitive period in amygdala development. This hyperexcitability contributes to increased excitatory gain in fear-learning circuits. Further, synaptic plasticity is enhanced in the BLA of Fmr1KO mice. Behavioral correlation demonstrates that fear-learning emerges precociously in the Fmr1KO mouse. Early life 4,5,6,7-tetrahydroisoxazolo [5,4-c]pyridin-3ol intervention ameliorates fear-learning in Fmr1KO mice. These results suggest that critical period plasticity in the amygdala of the Fmr1KO mouse may be shifted to earlier developmental time points.SIGNIFICANCE STATEMENT In these studies, we identify early developmental alterations in principal neurons in the Fragile X syndrome BLA. We show that, as early as P14, excitability and feedforward excitation, and synaptic plasticity are enhanced in Fmr1KO lateral amygdala. This correlates with precocious emergence of fear-learning in the Fmr1KO mouse. Early life 4,5,6,7-tetrahydroisoxazolo [5,4-c]pyridin-3ol intervention restores critical period plasticity in WT mice and ameliorates fear-learning in the Fmr1KO mouse.
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Affiliation(s)
- Matthew N Svalina
- Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Christian A Cea-Del Rio
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- CIBAP, Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile 9170201
| | - J Keenan Kushner
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Abigail Levy
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Serapio M Baca
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - E Mae Guthman
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Maya Opendak
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, New York 10962
- Child Study Center, Child & Adolescent Psychiatry, New York University School of Medicine, New York, 10016
| | - Regina M Sullivan
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, New York 10962
- Child Study Center, Child & Adolescent Psychiatry, New York University School of Medicine, New York, 10016
| | - Diego Restrepo
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Molly M Huntsman
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
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10
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Hooper AW, Wong H, Niibori Y, Abdoli R, Karumuthil-Melethil S, Qiao C, Danos O, Bruder JT, Hampson DR. Gene therapy using an ortholog of human fragile X mental retardation protein partially rescues behavioral abnormalities and EEG activity. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 22:196-209. [PMID: 34485605 PMCID: PMC8399347 DOI: 10.1016/j.omtm.2021.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 06/30/2021] [Indexed: 01/28/2023]
Abstract
Fragile X syndrome (FXS), a neurodevelopmental disorder with no known cure, is caused by a lack of expression of the fragile X mental retardation protein (FMRP). As a single-gene disorder, FXS is an excellent candidate for viral-vector-based gene therapy, although that is complicated by the existence of multiple isoforms of FMRP, whose individual cellular functions are unknown. We studied the effects of rat and mouse orthologs of human isoform 17, a major expressed isoform of FMRP. Injection of neonatal Fmr1 knockout rats and mice with adeno-associated viral vectors (AAV9 serotype) under the control of an MeCP2 mini-promoter resulted in widespread distribution of the FMRP transgenes throughout the telencephalon and diencephalon. Transgene expression occurred mainly in non-GABAergic neurons, with little expression in glia. Early postnatal treatment resulted in partial rescue of the Fmr1 KO rat phenotype, including improved social dominance in treated Fmr1 KO females and partial rescue of locomotor activity in males. Electro-encephalogram (EEG) recordings showed correction of abnormal slow-wave activity during the sleep-like state in male Fmr1 KO rats. These findings support the use of AAV-based gene therapy as a treatment for FXS and specifically demonstrate the potential therapeutic benefit of human FMRP isoform 17 orthologs.
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Affiliation(s)
- Alexander W.M. Hooper
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | - Hayes Wong
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | - Yosuke Niibori
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | - Rozita Abdoli
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | | | - Chunping Qiao
- Research and Early Development, REGENXBIO Inc. Rockville, Maryland, U.S.A. 20850
| | - Olivier Danos
- Research and Early Development, REGENXBIO Inc. Rockville, Maryland, U.S.A. 20850
| | - Joseph T. Bruder
- Research and Early Development, REGENXBIO Inc. Rockville, Maryland, U.S.A. 20850
| | - David R. Hampson
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 3M2
- Corresponding author: David R. Hampson, PhD, Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, Univerity of Toronto, ON M5S 3M2, Canada.
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11
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Smith E, Pedapati E, Liu R, Schmitt L, Dominick K, Shaffer R, Sweeney J, Erickson C. Sex differences in resting EEG power in Fragile X Syndrome. J Psychiatr Res 2021; 138:89-95. [PMID: 33836434 PMCID: PMC8192450 DOI: 10.1016/j.jpsychires.2021.03.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/10/2021] [Accepted: 03/24/2021] [Indexed: 12/21/2022]
Abstract
Electrophysiological alterations may represent a neural substrate of impaired neurocognitive processes and other phenotypic features in Fragile X Syndrome (FXS). However, the role of biological sex in electroencephalography (EEG) patterns that differentiate FXS from typical development has not been determined. This limits use of EEG in both the search for biomarkers of impairment in FXS as well as application of those markers to enhance our understanding of underlying neural mechanisms to speed treatment discovery. We investigated topographical relative EEG power in participants at rest in a sample of males and females with FXS and in age- and sex-matched typically developing controls (TDC) using a cluster-based analysis. While alterations in theta and low beta power were similar across males and females in FXS, relative power varied by sex in the alpha, upper beta, gamma, and epsilon frequency bands. Follow up analyses showed that Individual Alpha Peak Frequency (IAPF), a continuous variable that may capture atypicalities across the theta and alpha ranges in neurodevelopmental disorders, also varied by sex. Finally, performance on an auditory filtering task correlated with theta power in males, but not females with FXS. The impact of biological sex on resting state EEG power differences in FXS is discussed as it relates to potential GABAergic and glutamatergic etiologies of neurocognitive deficits in FXS.
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Affiliation(s)
- Elizabeth Smith
- Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Elizabeth G. Smith, corresponding author Cincinnati Children’s Hospital, 3333 Burnet Avenue, MLC 7039 Cincinnati, OH 45229 , (513) 517-1383
| | - Ernest Pedapati
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Rui Liu
- Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Lauren Schmitt
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Division of Developmental and Behavioral Pediatrics, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Kelli Dominick
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Rebecca Shaffer
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Division of Developmental and Behavioral Pediatrics, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - John Sweeney
- Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Craig Erickson
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
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12
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Proteau-Lemieux M, Knoth IS, Agbogba K, Côté V, Barlahan Biag HM, Thurman AJ, Martin CO, Bélanger AM, Rosenfelt C, Tassone F, Abbeduto LJ, Jacquemont S, Hagerman R, Bolduc F, Hessl D, Schneider A, Lippé S. EEG Signal Complexity Is Reduced During Resting-State in Fragile X Syndrome. Front Psychiatry 2021; 12:716707. [PMID: 34858220 PMCID: PMC8632368 DOI: 10.3389/fpsyt.2021.716707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: Fragile X syndrome (FXS) is a genetic disorder caused by a mutation of the fragile X mental retardation 1 gene (FMR1). FXS is associated with neurophysiological abnormalities, including cortical hyperexcitability. Alterations in electroencephalogram (EEG) resting-state power spectral density (PSD) are well-defined in FXS and were found to be linked to neurodevelopmental delays. Whether non-linear dynamics of the brain signal are also altered remains to be studied. Methods: In this study, resting-state EEG power, including alpha peak frequency (APF) and theta/beta ratio (TBR), as well as signal complexity using multi-scale entropy (MSE) were compared between 26 FXS participants (ages 5-28 years), and 7 neurotypical (NT) controls with a similar age distribution. Subsequently a replication study was carried out, comparing our cohort to 19 FXS participants independently recorded at a different site. Results: PSD results confirmed the increased gamma, decreased alpha power and APF in FXS participants compared to NT controls. No alterations in TBR were found. Importantly, results revealed reduced signal complexity in FXS participants, specifically in higher scales, suggesting that altered signal complexity is sensitive to brain alterations in this population. The replication study mostly confirmed these results and suggested critical points of stagnation in the neurodevelopmental curve of FXS. Conclusion: Signal complexity is a powerful feature that can be added to the electrophysiological biomarkers of brain maturation in FXS.
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Affiliation(s)
- Mélodie Proteau-Lemieux
- Department of Psychology, University of Montreal, Montreal, QC, Canada.,Research Center of the Sainte-Justine University Hospital, Montreal, QC, Canada
| | - Inga Sophia Knoth
- Research Center of the Sainte-Justine University Hospital, Montreal, QC, Canada
| | - Kristian Agbogba
- Research Center of the Sainte-Justine University Hospital, Montreal, QC, Canada
| | - Valérie Côté
- Research Center of the Sainte-Justine University Hospital, Montreal, QC, Canada
| | - Hazel Maridith Barlahan Biag
- University of California Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, United States
| | - Angela John Thurman
- University of California Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, United States
| | | | - Anne-Marie Bélanger
- Research Center of the Sainte-Justine University Hospital, Montreal, QC, Canada
| | - Cory Rosenfelt
- Department of Pediatric Neurology, University of Alberta, Edmonton, AB, Canada
| | - Flora Tassone
- University of California Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, United States.,Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA, United States
| | - Leonard J Abbeduto
- University of California Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, United States.,Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, United States
| | - Sébastien Jacquemont
- Research Center of the Sainte-Justine University Hospital, Montreal, QC, Canada.,Department of Pediatrics, University of Montreal, Montreal, QC, Canada
| | - Randi Hagerman
- University of California Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, United States
| | - François Bolduc
- Department of Pediatric Neurology, University of Alberta, Edmonton, AB, Canada
| | - David Hessl
- University of California Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, United States.,Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, United States
| | - Andrea Schneider
- University of California Davis Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA, United States.,California North State University, College of Psychology, Rancho Cordova, CA, United States
| | - Sarah Lippé
- Department of Psychology, University of Montreal, Montreal, QC, Canada.,Research Center of the Sainte-Justine University Hospital, Montreal, QC, Canada
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13
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Schaefer TL, Ashworth AA, Tiwari D, Tomasek MP, Parkins EV, White AR, Snider A, Davenport MH, Grainger LM, Becker RA, Robinson CK, Mukherjee R, Williams MT, Gibson JR, Huber KM, Gross C, Erickson CA. GABA A Alpha 2,3 Modulation Improves Select Phenotypes in a Mouse Model of Fragile X Syndrome. Front Psychiatry 2021; 12:678090. [PMID: 34093287 PMCID: PMC8175776 DOI: 10.3389/fpsyt.2021.678090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability. FXS is caused by functional loss of the Fragile X Protein (FXP), also known as Fragile X Mental Retardation Protein (FMRP). In humans and animal models, loss of FXP leads to sensory hypersensitivity, increased susceptibility to seizures and cortical hyperactivity. Several components of the GABAergic system, the major inhibitory system in the brain, are dysregulated in FXS, and thus modulation of GABAergic transmission was suggested and tested as a treatment strategy. However, so far, clinical trials using broad spectrum GABAA or GABAB receptor-specific agonists have not yielded broad improvement of FXS phenotypes in humans. Here, we tested a more selective strategy in Fmr1 knockout (KO) mice using the experimental drug BAER-101, which is a selective GABAA α2/α3 agonist. Our results suggest that BAER-101 reduces hyperexcitability of cortical circuits, partially corrects increased frequency-specific baseline cortical EEG power, reduces susceptibility to audiogenic seizures and improves novel object memory. Other Fmr1 KO-specific phenotypes were not improved by the drug, such as increased hippocampal dendritic spine density, open field activity and marble burying. Overall, this work shows that BAER-101 improves select phenotypes in Fmr1 KO mice and encourages further studies into the efficacy of GABAA-receptor subunit-selective agonists for the treatment of FXS.
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Affiliation(s)
- Tori L Schaefer
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Amy A Ashworth
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Madison P Tomasek
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Emma V Parkins
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Angela R White
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Andrew Snider
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Matthew H Davenport
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Lindsay M Grainger
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Robert A Becker
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Chandler K Robinson
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Rishav Mukherjee
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Michael T Williams
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Jay R Gibson
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Kimberly M Huber
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Craig A Erickson
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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14
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Gamma power abnormalities in a Fmr1-targeted transgenic rat model of fragile X syndrome. Sci Rep 2020; 10:18799. [PMID: 33139785 PMCID: PMC7608556 DOI: 10.1038/s41598-020-75893-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Fragile X syndrome (FXS) is characteristically displayed intellectual disability, hyperactivity, anxiety, and abnormal sensory processing. Electroencephalography (EEG) abnormalities are also observed in subjects with FXS, with many researchers paying attention to these as biomarkers. Despite intensive preclinical research using Fmr1 knock out (KO) mice, an effective treatment for FXS has yet to be developed. Here, we examined Fmr1-targeted transgenic rats (Fmr1-KO rats) as an alternative preclinical model of FXS. We characterized the EEG phenotypes of Fmr1-KO rats by measuring basal EEG power and auditory steady state response (ASSR) to click trains of stimuli at a frequency of 10–80 Hz. Fmr1-KO rats exhibited reduced basal alpha power and enhanced gamma power, and these rats showed enhanced locomotor activity in novel environment. While ASSR clearly peaked at around 40 Hz, both inter-trial coherence (ITC) and event-related spectral perturbation (ERSP) were significantly reduced at the gamma frequency band in Fmr1-KO rats. Fmr1-KO rats showed gamma power abnormalities and behavioral hyperactivity that were consistent with observations reported in mouse models and subjects with FXS. These results suggest that gamma power abnormalities are a translatable biomarker among species and demonstrate the utility of Fmr1-KO rats for investigating drugs for the treatment of FXS.
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15
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Wong H, Hooper AWM, Niibori Y, Lee SJ, Hategan LA, Zhang L, Karumuthil-Melethil S, Till SM, Kind PC, Danos O, Bruder JT, Hampson DR. Sexually dimorphic patterns in electroencephalography power spectrum and autism-related behaviors in a rat model of fragile X syndrome. Neurobiol Dis 2020; 146:105118. [PMID: 33031903 DOI: 10.1016/j.nbd.2020.105118] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/14/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
Fragile X syndrome (FXS), a neurodevelopmental disorder with autistic features, is caused by the loss of the fragile X mental retardation protein. Sex-specific differences in the clinical profile have been observed in FXS patients, but few studies have directly compared males and females in rodent models of FXS. To address this, we performed electroencephalography (EEG) recordings and a battery of autism-related behavioral tasks on juvenile and young adult Fmr1 knockout (KO) rats. EEG analysis demonstrated that compared to wild-type, male Fmr1 KO rats showed an increase in gamma frequency band power in the frontal cortex during the sleep-like immobile state, and both male and female KO rats failed to show an increase in delta frequency power in the sleep-like state, as observed in wild-type rats. Previous studies of EEG profiles in FXS subjects also reported abnormally increased gamma frequency band power, highlighting this parameter as a potential translatable biomarker. Both male and female Fmr1 KO rats displayed reduced exploratory behaviors in the center zone of the open field test, and increased distance travelled in an analysis of 24-h home cage activity, an effect that was more prominent during the nocturnal phase. Reduced wins against wild-type opponents in the tube test of social dominance was seen in both sexes. In contrast, increased repetitive behaviors in the wood chew test was observed in male but not female KO rats, while increased freezing in a fear conditioning test was observed only in the female KO rats. Our findings highlight sex differences between male and female Fmr1 KO rats, and indicate that the rat model of FXS could be a useful tool for the development of new therapeutics for treating this debilitating neurodevelopmental disorder.
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Affiliation(s)
- Hayes Wong
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | | | - Yosuke Niibori
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Shiron J Lee
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Luca A Hategan
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | | | - Sally M Till
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Olivier Danos
- Research and Early Development, REGENXBIO Inc., Rockville, MD, USA
| | - Joseph T Bruder
- Research and Early Development, REGENXBIO Inc., Rockville, MD, USA
| | - David R Hampson
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada; Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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16
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Castagnola S, Cazareth J, Lebrigand K, Jarjat M, Magnone V, Delhaye S, Brau F, Bardoni B, Maurin T. Agonist-induced functional analysis and cell sorting associated with single-cell transcriptomics characterizes cell subtypes in normal and pathological brain. Genome Res 2020; 30:1633-1642. [PMID: 32973039 PMCID: PMC7605246 DOI: 10.1101/gr.262717.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 09/23/2020] [Indexed: 12/31/2022]
Abstract
To gain better insight into the dynamic interaction between cells and their environment, we developed the agonist-induced functional analysis and cell sorting (aiFACS) technique, which allows the simultaneous recording and sorting of cells in real-time according to their immediate and individual response to a stimulus. By modulating the aiFACS selection parameters, testing different developmental times, using various stimuli, and multiplying the analysis of readouts, it is possible to analyze cell populations of any normal or pathological tissue. The association of aiFACS with single-cell transcriptomics allows the construction of functional tissue cartography based on specific pharmacological responses of cells. As a proof of concept, we used aiFACS on the dissociated mouse brain, a highly heterogeneous tissue, enriching it in interneurons by stimulation with KCl or with AMPA, an agonist of the glutamate receptors, followed by sorting based on calcium levels. After AMPA stimulus, single-cell transcriptomics of these aiFACS-selected interneurons resulted in a nine-cluster classification. Furthermore, we used aiFACS on interneurons derived from the brain of the Fmr1-KO mouse, a rodent model of fragile X syndrome. We showed that these interneurons manifest a generalized defective response to AMPA compared with wild-type cells, affecting all the analyzed cell clusters at one specific postnatal developmental time.
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Affiliation(s)
- Sara Castagnola
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Julie Cazareth
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Kevin Lebrigand
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Marielle Jarjat
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Virginie Magnone
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Sébastien Delhaye
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Frederic Brau
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Barbara Bardoni
- Université Côte d'Azur, INSERM, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
| | - Thomas Maurin
- Université Côte d'Azur, CNRS, Institute of Molecular Cellular Pharmacology, F-06560 Valbonne, France
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17
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Ostrovskaya OI, Cao G, Eroglu C, Harris KM. Developmental onset of enduring long-term potentiation in mouse hippocampus. Hippocampus 2020; 30:1298-1312. [PMID: 32894631 DOI: 10.1002/hipo.23257] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/18/2020] [Accepted: 08/13/2020] [Indexed: 11/10/2022]
Abstract
Analysis of long-term potentiation (LTP) provides a powerful window into cellular mechanisms of learning and memory. Prior work shows late LTP (L-LTP), lasting >3 hr, occurs abruptly at postnatal day 12 (P12) in the stratum radiatum of rat hippocampal area CA1. The goal here was to determine the developmental profile of synaptic plasticity leading to L-LTP in the mouse hippocampus. Two mouse strains and two mutations known to affect synaptic plasticity were chosen: C57BL/6J and Fmr1-/y on the C57BL/6J background, and 129SVE and Hevin-/- (Sparcl1-/- ) on the 129SVE background. Like rats, hippocampal slices from all of the mice showed test pulse-induced depression early during development that was gradually resolved with maturation by 5 weeks. All the mouse strains showed a gradual progression between P10-P35 in the expression of short-term potentiation (STP), lasting ≤1 hr. In the 129SVE mice, L-LTP onset (>25% of slices) occurred by 3 weeks, reliable L-LTP (>50% slices) was achieved by 4 weeks, and Hevin-/- advanced this profile by 1 week. In the C57BL/6J mice, L-LTP onset occurred significantly later, over 3-4 weeks, and reliability was not achieved until 5 weeks. Although some of the Fmr1-/y mice showed L-LTP before 3 weeks, reliable L-LTP also was not achieved until 5 weeks. L-LTP onset was not advanced in any of the mouse genotypes by multiple bouts of theta-burst stimulation at 90 or 180 min intervals. These findings show important species differences in the onset of STP and L-LTP, which occur at the same age in rats but are sequentially acquired in mice.
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Affiliation(s)
- Olga I Ostrovskaya
- Department of Neuroscience, Center for Learning and Memory, The University of Texas at Austin, Austin, Texas, USA
| | - Guan Cao
- Department of Neuroscience, Center for Learning and Memory, The University of Texas at Austin, Austin, Texas, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA.,Department of Neurobiology Regeneration Next Initiative, Duke University Medical Center, Durham, North Carolina, USA
| | - Kristen M Harris
- Department of Neuroscience, Center for Learning and Memory, The University of Texas at Austin, Austin, Texas, USA
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18
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Shi D, Xu S, Zhuo J, McKenna MC, Gullapalli RP. White Matter Alterations in Fmr1 Knockout Mice during Early Postnatal Brain Development. Dev Neurosci 2020; 41:274-289. [PMID: 32348987 DOI: 10.1159/000506679] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/19/2020] [Indexed: 01/20/2023] Open
Abstract
Fragile X syndrome (FXS) is the most commonly inherited form of intellectual disability ascribed to the autism spectrum disorder. Studies with FXS patients have reported altered white matter volume compared to controls. The Fmr1 knockout (KO) mouse, a model for FXS, showed evidence of delayed myelination during postnatal brain development. In this study, we examined several white matter regions in the male Fmr1 KO mouse brain compared to male wild-type (WT) mice at postnatal days (PND) 18, 21, 30, and 60, which coincide with critical stages of myelination and postnatal brain development. White matter volume, T2 relaxation time, and magnetization transfer ratio (MTR) were measured using magnetic resonance imaging and myelin content was determined with histological staining of myelin. Differences in the developmental accumulation of white matter and myelin between Fmr1 KO and WT mice were observed in the corpus callosum, external and internal capsules, cerebral peduncle, and fimbria. Alterations were more predominant in the external and internal capsules and fimbria of Fmr1 KO mice, where the MTR was lower at PND 18, then elevated at PND 30, and again lower at PND 60 compared to the corresponding regions in WT mice. The pattern of changes in MTR were similar to those observed in myelin staining and could be related to the altered protein synthesis that is a hallmark of FXS. While no significant changes in white matter volumes and T2 relaxation time between the Fmr1 KO and WT mice were observed, the altered pattern of myelin staining and MTR, particularly in the external capsule, reflecting the abnormalities associated with myelin content is suggestive of a developmental delay in the white matter of Fmr1 KO mouse brain. These early differences in white matter during critical developmental stages may contribute to altered brain networks in the Fmr1 KO mice.
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Affiliation(s)
- Da Shi
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jiachen Zhuo
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mary C McKenna
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Rao P Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA, .,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA, .,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, USA,
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19
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Markicevic M, Fulcher BD, Lewis C, Helmchen F, Rudin M, Zerbi V, Wenderoth N. Cortical Excitation:Inhibition Imbalance Causes Abnormal Brain Network Dynamics as Observed in Neurodevelopmental Disorders. Cereb Cortex 2020; 30:4922-4937. [PMID: 32313923 PMCID: PMC7391279 DOI: 10.1093/cercor/bhaa084] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abnormal brain development manifests itself at different spatial scales. However, whether abnormalities at the cellular level can be diagnosed from network activity measured with functional magnetic resonance imaging (fMRI) is largely unknown, yet of high clinical relevance. Here a putative mechanism reported in neurodevelopmental disorders, that is, excitation-to-inhibition ratio (E:I), was chemogenetically increased within cortical microcircuits of the mouse brain and measured via fMRI. Increased E:I caused a significant "reduction" of long-range connectivity, irrespective of whether excitatory neurons were facilitated or inhibitory Parvalbumin (PV) interneurons were suppressed. Training a classifier on fMRI signals, we were able to accurately classify cortical areas exhibiting increased E:I. This classifier was validated in an independent cohort of Fmr1y/- knockout mice, a model for autism with well-documented loss of parvalbumin neurons and chronic alterations of E:I. Our findings demonstrate a promising novel approach towards inferring microcircuit abnormalities from macroscopic fMRI measurements.
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Affiliation(s)
- Marija Markicevic
- Neural Control of Movement Lab, HEST, ETH Zürich, 8093 Zurich, Switzerland.,Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Ben D Fulcher
- School of Physics, The University of Sydney, NSW 2006, Australia
| | - Christopher Lewis
- Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Fritjof Helmchen
- Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland.,Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Markus Rudin
- Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland.,Institute for Biomedical Engineering, University and ETH Zurich, 8093 Zurich, Switzerland
| | - Valerio Zerbi
- Neural Control of Movement Lab, HEST, ETH Zürich, 8093 Zurich, Switzerland.,Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Nicole Wenderoth
- Neural Control of Movement Lab, HEST, ETH Zürich, 8093 Zurich, Switzerland.,Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
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20
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Deutsch SI, Burket JA. An Evolving Therapeutic Rationale for Targeting the α 7 Nicotinic Acetylcholine Receptor in Autism Spectrum Disorder. Curr Top Behav Neurosci 2020; 45:167-208. [PMID: 32468495 DOI: 10.1007/7854_2020_136] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Abnormalities of cholinergic nuclei, cholinergic projections, and cholinergic receptors, as well as abnormalities of growth factors involved in the maturation and maintenance of cholinergic neurons, have been described in postmortem brains of persons with autism spectrum disorder (ASD). Further, microdeletions of the 15q13.3 locus that encompasses CHRNA7, the gene coding the α7 nicotinic acetylcholine receptor (α7 nAChR), are associated with a spectrum of neurodevelopmental disorders, including ASD. The heterozygous 15q13.3 microdeletion syndrome suggests that diminished or impaired transduction of the acetylcholine (ACh) signal by the α7 nAChR can be a pathogenic mechanism of ASD. The α7 nAChR has a role in regulating the firing and function of parvalbumin (PV)-expressing GABAergic projections, which synchronize the oscillatory output of assemblies of pyramidal neurons onto which they project. Synchronous oscillatory output is an electrophysiological substrate for higher executive functions, such as working memory, and functional connectivity between discrete anatomic areas of the brain. The α7 nAChR regulates PV expression and works cooperatively with the co-expressed NMDA receptor in subpopulations of GABAergic interneurons in mouse models of ASD. An evolving literature supports therapeutic exploration of selectively targeted cholinergic interventions for the treatment of ASD, especially compounds that target the α7 nAChR subtype. Importantly, development and availability of high-affinity, brain-penetrable, α7 nAChR-selective agonists, partial agonists, allosteric agonists, and positive allosteric modulators (PAMs) should facilitate "proof-of-principle/concept" clinical trials. nAChRs are pentameric allosteric proteins that function as ligand-gated ion channel receptors constructed from five constituent polypeptide subunits, all of which share a common structural motif. Importantly, in addition to α7 nAChR-gated Ca2+ conductance causing membrane depolarization, there are emerging data consistent with possible metabotropic functions of this ionotropic receptor. The ability of α7-selective type II PAMs to "destabilize" the desensitized state and promote ion channel opening may afford them therapeutic advantages over orthosteric agonists. The current chapter reviews historic and recent literature supporting selective therapeutic targeting of the α7 nAChR in persons affected with ASD.
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Affiliation(s)
- Stephen I Deutsch
- Department of Psychiatry and Behavioral Sciences, Eastern Virginia Medical School, Norfolk, VA, USA.
| | - Jessica A Burket
- Department of Molecular Biology and Chemistry, Christopher Newport University, Newport News, VA, USA
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21
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Gonzalez D, Tomasek M, Hays S, Sridhar V, Ammanuel S, Chang CW, Pawlowski K, Huber KM, Gibson JR. Audiogenic Seizures in the Fmr1 Knock-Out Mouse Are Induced by Fmr1 Deletion in Subcortical, VGlut2-Expressing Excitatory Neurons and Require Deletion in the Inferior Colliculus. J Neurosci 2019; 39:9852-9863. [PMID: 31666356 PMCID: PMC6891051 DOI: 10.1523/jneurosci.0886-19.2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/06/2019] [Accepted: 10/16/2019] [Indexed: 02/07/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and the leading monogenetic cause of autism. One symptom of FXS and autism is sensory hypersensitivity (also called sensory over-responsivity). Perhaps related to this, the audiogenic seizure (AGS) is arguably the most robust behavioral phenotype in the FXS mouse model-the Fmr1 knock-out (KO) mouse. Therefore, the AGS may be considered a mouse model of sensory hypersensitivity. Hyperactive circuits are hypothesized to underlie dysfunction in a number of brain regions in patients with FXS and Fmr1 KO mice, and the AGS may be a result of this. But the specific cell types and brain regions underlying AGSs in the Fmr1 KO are unknown. We used conditional deletion or expression of Fmr1 in different cell populations to determine whether Fmr1 deletion in those cells was sufficient or necessary, respectively, for the AGS phenotype in males. Our data indicate that Fmr1 deletion in glutamatergic neurons that express vesicular glutamate transporter 2 (VGlut2) and are located in subcortical brain regions is sufficient and necessary to cause AGSs. Furthermore, the deletion of Fmr1 in glutamatergic neurons of the inferior colliculus is necessary for AGSs. When we demonstrate necessity, we show that Fmr1 expression in either the larger population of VGlut2-expressing glutamatergic neurons or the smaller population of inferior collicular glutamatergic neurons-in an otherwise Fmr1 KO mouse-eliminates AGSs. Therefore, targeting these neuronal populations in FXS and autism may be part of a therapeutic strategy to alleviate sensory hypersensitivity.SIGNIFICANCE STATEMENT Sensory hypersensitivity in fragile X syndrome (FXS) and autism patients significantly interferes with quality of life. Audiogenic seizures (AGSs) are arguably the most robust behavioral phenotype in the FXS mouse model-the Fmr1 knockout-and may be considered a model of sensory hypersensitivity in FXS. We provide the clearest and most precise genetic evidence to date for the cell types and brain regions involved in causing AGSs in the Fmr1 knockout and, more broadly, for any mouse mutant. The expression of Fmr1 in these same cell types in an otherwise Fmr1 knockout eliminates AGSs indicating possible cellular targets for alleviating sensory hypersensitivity in FXS and other forms of autism.
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Affiliation(s)
| | | | - Seth Hays
- Department of Neuroscience, Dallas, and
| | | | | | | | - Karen Pawlowski
- Department of Otolaryngology and Biomedical Engineering Program, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9035
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22
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Domanski APF, Booker SA, Wyllie DJA, Isaac JTR, Kind PC. Cellular and synaptic phenotypes lead to disrupted information processing in Fmr1-KO mouse layer 4 barrel cortex. Nat Commun 2019; 10:4814. [PMID: 31645553 PMCID: PMC6811545 DOI: 10.1038/s41467-019-12736-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 09/23/2019] [Indexed: 02/06/2023] Open
Abstract
Sensory hypersensitivity is a common and debilitating feature of neurodevelopmental disorders such as Fragile X Syndrome (FXS). How developmental changes in neuronal function culminate in network dysfunction that underlies sensory hypersensitivities is unknown. By systematically studying cellular and synaptic properties of layer 4 neurons combined with cellular and network simulations, we explored how the array of phenotypes in Fmr1-knockout (KO) mice produce circuit pathology during development. We show that many of the cellular and synaptic pathologies in Fmr1-KO mice are antagonistic, mitigating circuit dysfunction, and hence may be compensatory to the primary pathology. Overall, the layer 4 network in the Fmr1-KO exhibits significant alterations in spike output in response to thalamocortical input and distorted sensory encoding. This developmental loss of layer 4 sensory encoding precision would contribute to subsequent developmental alterations in layer 4-to-layer 2/3 connectivity and plasticity observed in Fmr1-KO mice, and circuit dysfunction underlying sensory hypersensitivity.
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Affiliation(s)
- Aleksander P F Domanski
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK.
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
- Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
- Developmental Synaptic Plasticity Section, NINDS, NIH, Bethesda, MD, 20892, USA.
| | - Sam A Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
- Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - David J A Wyllie
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
- Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
- Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India
| | - John T R Isaac
- Developmental Synaptic Plasticity Section, NINDS, NIH, Bethesda, MD, 20892, USA.
- Janssen Neuroscience, J&J London Innovation Centre, J&J London Innovation Centre, One Chapel Place, London, W1G 0B, UK.
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
- Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
- Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India.
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23
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Ethridge LE, De Stefano LA, Schmitt LM, Woodruff NE, Brown KL, Tran M, Wang J, Pedapati EV, Erickson CA, Sweeney JA. Auditory EEG Biomarkers in Fragile X Syndrome: Clinical Relevance. Front Integr Neurosci 2019; 13:60. [PMID: 31649514 PMCID: PMC6794497 DOI: 10.3389/fnint.2019.00060] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 09/24/2019] [Indexed: 12/21/2022] Open
Abstract
Sensory hypersensitivities are common and distressing features of Fragile X Syndrome (FXS). While there are many drug interventions that reduce behavioral deficits in Fmr1 mice and efforts to translate these preclinical breakthroughs into clinical trials for FXS, evidence-based clinical interventions are almost non-existent potentially due to lack of valid neural biomarkers. Local circuit function in sensory networks is dependent on the dynamic balance of activity in inhibitory/excitatory synapses. Studies are needed to examine the association of electrophysiological alterations in neural systems with sensory and other clinical features of FXS to establish their clinical relevance. Adolescents and adults with FXS (n = 38, Mean age = 25.5, std = 10.1; 13 females) and age matched typically developing controls (n = 40, Mean age = 27.7, std = 12.1; 17 females) completed auditory chirp and auditory habituation tasks while undergoing dense array electroencephalography (EEG). Amplitude, latency, and percent change (habituation) in N1 and P2 event-related potential (ERP) components were characterized for the habituation task; time-frequency calculations using Morlet wavelets characterized phase-locking and single trial power for the habituation and chirp tasks. FXS patients showed increased amplitude but some evidence for reduced habituation of the N1 ERP, and reduced phase-locking in the low and high gamma frequency range and increased low gamma power to the chirp stimulus. FXS showed increased theta power in both tasks. While the habituation finding was weaker than previously found, the remaining findings replicate our previous work in a new sample of patients with FXS. Females showed less deficit in the chirp task but not the habituation task. Abnormal increases in gamma power were related to more severe behavioral and psychiatric features as well as reductions in neurocognitive abilities. Replicating electrophysiological deficits in a new group of patients using different EEG equipment at a new data collection site with differing levels of environmental noise that were robust to data processing techniques utilizing multiple researchers, indicates a potential for scalability to multi-site clinical trials. Given the robust replicability, relevance to clinical measures, and preclinical evidence for sensitivity of these EEG measures to pharmacological intervention, the observed abnormalities may provide novel translational markers of target engagement and potentially outcome measures in large-scale studies evaluating new treatments targeting neural hyperexcitability in FXS.
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Affiliation(s)
- Lauren E Ethridge
- Department of Pediatrics, Section of Developmental and Behavioral Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Psychology, The University of Oklahoma, Norman, OK, United States
| | - Lisa A De Stefano
- Department of Psychology, The University of Oklahoma, Norman, OK, United States
| | - Lauren M Schmitt
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, United States
| | - Nicholas E Woodruff
- Department of Psychology, The University of Oklahoma, Norman, OK, United States
| | - Kara L Brown
- Department of Psychology, The University of Oklahoma, Norman, OK, United States
| | - Morgan Tran
- Department of Psychology, The University of Oklahoma, Norman, OK, United States
| | - Jun Wang
- Department of Psychology, Zhejiang Normal University, Jinhua, China
| | - Ernest V Pedapati
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, United States.,Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Division of Child Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Craig A Erickson
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, United States.,Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - John A Sweeney
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, United States
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24
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Kroon T, Dawitz J, Kramvis I, Anink J, Obermayer J, Verhoog MB, Wilbers R, Goriounova NA, Idema S, Baayen JC, Aronica E, Mansvelder HD, Meredith RM. Group I mGluR-Mediated Activation of Martinotti Cells Inhibits Local Cortical Circuitry in Human Cortex. Front Cell Neurosci 2019; 13:315. [PMID: 31354435 PMCID: PMC6637283 DOI: 10.3389/fncel.2019.00315] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/27/2019] [Indexed: 11/13/2022] Open
Abstract
Group I metabotropic glutamate receptors (mGluRs) mediate a range of signaling and plasticity processes in the brain and are of growing importance as potential therapeutic targets in clinical trials for neuropsychiatric and neurodevelopmental disorders (NDDs). Fundamental knowledge regarding the functional effects of mGluRs upon pyramidal neurons and interneurons is derived largely from rodent brain, and their effects upon human neurons are predominantly untested. We therefore addressed how group I mGluRs affect microcircuits in human neocortex. We show that activation of group I mGluRs elicits action potential firing in Martinotti cells, which leads to increased synaptic inhibition onto neighboring neurons. Some other interneurons, including fast-spiking interneurons, are depolarized but do not fire action potentials in response to group I mGluR activation. Furthermore, we confirm the existence of group I mGluR-mediated depression of excitatory synapses in human pyramidal neurons. We propose that the strong increase in inhibition and depression of excitatory synapses onto layer 2/3 pyramidal neurons upon group I mGluR activation likely results in a shift in the balance between excitation and inhibition in the human cortical network.
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Affiliation(s)
- Tim Kroon
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - Julia Dawitz
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - Ioannis Kramvis
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - Jasper Anink
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland, Heemstede, Netherlands
| | - Joshua Obermayer
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - Matthijs B. Verhoog
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - René Wilbers
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - Natalia A. Goriounova
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - Sander Idema
- Department of Neurosurgery, VU University Medical Center, Amsterdam, Netherlands
| | - Johannes C. Baayen
- Department of Neurosurgery, VU University Medical Center, Amsterdam, Netherlands
| | - Eleonora Aronica
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland, Heemstede, Netherlands
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - Rhiannon M. Meredith
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
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25
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Lee FHF, Lai TKY, Su P, Liu F. Altered cortical Cytoarchitecture in the Fmr1 knockout mouse. Mol Brain 2019; 12:56. [PMID: 31200759 PMCID: PMC6570929 DOI: 10.1186/s13041-019-0478-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/03/2019] [Indexed: 12/15/2022] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by silencing of the FMR1 gene and subsequent loss of its protein product, fragile X retardation protein (FMRP). One of the most robust neuropathological findings in post-mortem human FXS and Fmr1 KO mice is the abnormal increase in dendritic spine densities, with the majority of spines showing an elongated immature morphology. However, the exact mechanisms of how FMRP can regulate dendritic spine development are still unclear. Abnormal dendritic spines can result from disturbances of multiple factors during neurodevelopment, such as alterations in neuron numbers, position and glial cells. In this study, we undertook a comprehensive histological analysis of the cerebral cortex in Fmr1 KO mice. They displayed significantly fewer neuron and PV-interneuron numbers, along with altered cortical lamination patterns. In terms of glial cells, Fmr1 KO mice exhibited an increase in Olig2-oligodendrocytes, which corresponded to the abnormally higher myelin expression in the corpus callosum. Iba1-microglia were significantly reduced but GFAP-astrocyte numbers and intensity were elevated. Using primary astrocytes derived from KO mice, we further demonstrated the presence of astrogliosis characterized by an increase in GFAP expression and astrocyte hypertrophy. Our findings provide important information on the cortical architecture of Fmr1 KO mice, and insights towards possible mechanisms associated with FXS.
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Affiliation(s)
- Frankie H F Lee
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8, Canada
| | - Terence K Y Lai
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, M5T 1R8, Canada
| | - Ping Su
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8, Canada
| | - Fang Liu
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8, Canada. .,Department of Physiology, University of Toronto, Toronto, Ontario, M5T 1R8, Canada. .,Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8, Canada.
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26
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Bodaleo F, Tapia-Monsalves C, Cea-Del Rio C, Gonzalez-Billault C, Nunez-Parra A. Structural and Functional Abnormalities in the Olfactory System of Fragile X Syndrome Models. Front Mol Neurosci 2019; 12:135. [PMID: 31191246 PMCID: PMC6548058 DOI: 10.3389/fnmol.2019.00135] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/09/2019] [Indexed: 12/18/2022] Open
Abstract
Fragile X Syndrome (FXS) is the most common inherited form of intellectual disability. It is produced by mutation of the Fmr1 gene that encodes for the Fragile Mental Retardation Protein (FMRP), an important RNA-binding protein that regulates the expression of multiple proteins located in neuronal synapses. Individuals with FXS exhibit abnormal sensory information processing frequently leading to hypersensitivity across sensory modalities and consequently a wide array of behavioral symptoms. Insects and mammals engage primarily their sense of smell to create proper representations of the external world and guide adequate decision-making processes. This feature in combination with the exquisitely organized neuronal circuits found throughout the olfactory system (OS) and the wide expression of FMRP in brain regions that process olfactory information makes it an ideal model to study sensory alterations in FXS models. In the last decade several groups have taken advantage of these features and have used the OS of fruit fly and rodents to understand neuronal alteration giving rise to sensory perception issues. In this review article, we will discuss molecular, morphological and physiological aspects of the olfactory information processing in FXS models. We will highlight the decreased inhibitory/excitatory synaptic balance and the diminished synaptic plasticity found in this system resulting in behavioral alteration of individuals in the presence of odorant stimuli.
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Affiliation(s)
- Felipe Bodaleo
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile
| | | | - Christian Cea-Del Rio
- Laboratory of Neurophysiopathology, Centro de Investigacion Biomedica y Aplicada (CIBAP), School of Medicine, Universidad de Santiago de Chile, Santiago, Chile
| | - Christian Gonzalez-Billault
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile.,The Buck Institute for Research on Aging, Novato, CA, United States
| | - Alexia Nunez-Parra
- Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Cell Physiology Center, Universidad de Chile, Santiago, Chile
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27
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Lazaro MT, Taxidis J, Shuman T, Bachmutsky I, Ikrar T, Santos R, Marcello GM, Mylavarapu A, Chandra S, Foreman A, Goli R, Tran D, Sharma N, Azhdam M, Dong H, Choe KY, Peñagarikano O, Masmanidis SC, Rácz B, Xu X, Geschwind DH, Golshani P. Reduced Prefrontal Synaptic Connectivity and Disturbed Oscillatory Population Dynamics in the CNTNAP2 Model of Autism. Cell Rep 2019; 27:2567-2578.e6. [PMID: 31141683 PMCID: PMC6553483 DOI: 10.1016/j.celrep.2019.05.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/20/2019] [Accepted: 04/30/2019] [Indexed: 11/25/2022] Open
Abstract
Loss-of-function mutations in CNTNAP2 cause a syndromic form of autism spectrum disorder in humans and produce social deficits, repetitive behaviors, and seizures in mice. However, the functional effects of these mutations at cellular and circuit levels remain elusive. Using laser-scanning photostimulation, whole-cell recordings, and electron microscopy, we found a dramatic decrease in excitatory and inhibitory synaptic inputs onto L2/3 pyramidal neurons of the medial prefrontal cortex (mPFC) of Cntnap2 knockout (KO) mice, concurrent with reduced spines and synapses, despite normal dendritic complexity and intrinsic excitability. Moreover, recording of mPFC local field potentials (LFPs) and unit spiking in vivo revealed increased activity in inhibitory neurons, reduced phase-locking to delta and theta oscillations, and delayed phase preference during locomotion. Excitatory neurons showed similar phase modulation changes at delta frequencies. Finally, pairwise correlations increased during immobility in KO mice. Thus, reduced synaptic inputs can yield perturbed temporal coordination of neuronal firing in cortical ensembles.
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Affiliation(s)
- Maria T Lazaro
- Interdepartmental Program for Neuroscience, UCLA, Los Angeles, CA, USA; Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Jiannis Taxidis
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Tristan Shuman
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Iris Bachmutsky
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - Rommel Santos
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - G Mark Marcello
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Apoorva Mylavarapu
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Swasty Chandra
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Allison Foreman
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Rachna Goli
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Duy Tran
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Nikhil Sharma
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Michelle Azhdam
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Hongmei Dong
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Katrina Y Choe
- Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA
| | - Olga Peñagarikano
- Department of Pharmacology, School of Medicine, University of the Basque Country (UPV/EHU), Vizcaya, Spain; Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Madrid, Spain
| | - Sotiris C Masmanidis
- Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Bence Rácz
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - Daniel H Geschwind
- Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Center for Autism Research and Treatment, Semel Institute, UCLA, Los Angeles, CA, USA; Intellectual Development and Disabilities Research Center, UCLA, Los Angeles, CA, USA.
| | - Peyman Golshani
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA; Intellectual Development and Disabilities Research Center, UCLA, Los Angeles, CA, USA; West Los Angeles VA Medical Center, Los Angeles, CA.
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Kinase pathway inhibition restores PSD95 induction in neurons lacking fragile X mental retardation protein. Proc Natl Acad Sci U S A 2019; 116:12007-12012. [PMID: 31118285 DOI: 10.1073/pnas.1812056116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fragile X syndrome (FXS) is the leading monogenic cause of autism and intellectual disability. FXS is caused by loss of expression of fragile X mental retardation protein (FMRP), an RNA-binding protein that regulates translation of numerous mRNA targets, some of which are present at synapses. While protein synthesis deficits have long been postulated as an etiology of FXS, how FMRP loss affects distributions of newly synthesized proteins is unknown. Here we investigated the role of FMRP in regulating expression of new copies of the synaptic protein PSD95 in an in vitro model of synaptic plasticity. We find that local BDNF application promotes persistent accumulation of new PSD95 at stimulated synapses and dendrites of cultured neurons, and that this accumulation is absent in FMRP-deficient mouse neurons. New PSD95 accumulation at sites of BDNF stimulation does not require known mechanisms regulating FMRP-mRNA interactions but instead requires the PI3K-mTORC1-S6K1 pathway. Surprisingly, in FMRP-deficient neurons, BDNF induction of new PSD95 accumulation can be restored by mTORC1-S6K1 blockade, suggesting that constitutively high mTORC1-S6K1 activity occludes PSD95 regulation by BDNF and that alternative pathways exist to mediate induction when mTORC1-S6K1 is inhibited. This study provides direct evidence for deficits in local protein synthesis and accumulation of newly synthesized protein in response to local stimulation in FXS, and supports mTORC1-S6K1 pathway inhibition as a potential therapeutic approach for FXS.
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Metabotropic functions of the NMDA receptor and an evolving rationale for exploring NR2A-selective positive allosteric modulators for the treatment of autism spectrum disorder. Prog Neuropsychopharmacol Biol Psychiatry 2019; 90:142-160. [PMID: 30481555 DOI: 10.1016/j.pnpbp.2018.11.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 11/19/2018] [Accepted: 11/22/2018] [Indexed: 12/18/2022]
Abstract
NMDA receptors are widely distributed throughout the brain and major therapeutic challenges include targeting specific NMDA receptor subtypes while preserving spatial and temporal specificity during their activation. The NR2A-subunit containing NMDA receptor is implicated in regulating synchronous oscillatory output of cortical pyramidal neurons, which may be disturbed in clinical presentations of autism spectrum disorder (ASD). Because NR2A-selective positive allosteric modulators (PAMs) preserve spatial and temporal selectivity while activating this subpopulation of receptors, they represent a promising strategy to address neocortical circuit abnormalities in ASD. In addition to promoting Ca2+ entry and membrane depolarization, diverse metabotropic effects of NMDA receptor activation on signal transduction pathways occur within the cell, some of which depend on alignment of protein binding partners. For example, NMDA receptor agonist interventions attenuate impaired sociability in transgenic mice with 'loss-of-function' mutations of the Shank family of scaffolding proteins, which highlights the necessity of a carefully orchestrated alignment of protein binding partners in the excitatory synapse. The current Review considers metabotropic functions of the NMDA receptor that could play a role in sociability and the pathogenesis of ASD (e.g., mTOR signaling), in addition to its more familiar ionotropic functions, and provides a rationale for therapeutic exploration of NR2A-selective PAMs.
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Developmental excitatory-to-inhibitory GABA polarity switch is delayed in Ts65Dn mice, a genetic model of Down syndrome. Neurobiol Dis 2018; 115:1-8. [PMID: 29550538 DOI: 10.1016/j.nbd.2018.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 11/23/2022] Open
Abstract
Down syndrome (DS) is the most frequent genetic cause of developmental abnormalities leading to intellectual disability. One notable phenomenon affecting the formation of nascent neural circuits during late developmental periods is developmental switch of GABA action from depolarizing to hyperpolarizing mode. We examined properties of this switch in DS using primary cultures and acute hippocampal slices from Ts65Dn mice, a genetic model of DS. Cultures of DIV3-DIV13 Ts65Dn and control normosomic (2 N) neurons were loaded with FURA-2 AM, and GABA action was assessed using local applications. In 2 N cultures, the number of GABA-activated cells dropped from ~100% to 20% between postnatal days 3-13 (P3-P13) reflecting the switch in GABA action polarity. In Ts65Dn cultures, the timing of this switch was delayed by 2-3 days. Next, microelectrode recordings of multi-unit activity (MUA) were performed in CA3 slices during bath application of the GABAA agonist isoguvacine. MUA frequency was increased in P8-P12 and reduced in P14-P22 slices reflecting the switch of GABA action from excitatory to inhibitory mode. The timing of this switch was delayed in Ts65Dn by approximately 2 days. Finally, frequency of giant depolarizing potentials (GDPs), a form of primordial neural activity, was significantly increased in slices from Ts65Dn pups at P12 and P14. These experimental evidences show that GABA action polarity switch is delayed in Ts65Dn model of DS, and that these changes lead to a delay in maturation of nascent neural circuits. These alterations may affect properties of neural circuits in adult animals and, therefore, represent a prospective target for pharmacotherapy of cognitive impairment in DS.
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Enhanced Operant Extinction and Prefrontal Excitability in a Mouse Model of Angelman Syndrome. J Neurosci 2018; 38:2671-2682. [PMID: 29431654 DOI: 10.1523/jneurosci.2828-17.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/24/2018] [Accepted: 01/27/2018] [Indexed: 01/01/2023] Open
Abstract
Angelman syndrome (AS), a neurodevelopmental disorder associated with intellectual disability, is caused by loss of maternal allele expression of UBE3A in neurons. Mouse models of AS faithfully recapitulate disease phenotypes across multiple domains, including behavior. Yet in AS, there has been only limited study of behaviors encoded by the prefrontal cortex, a region broadly involved in executive function and cognition. Because cognitive impairment is a core feature of AS, it is critical to develop behavioral readouts of prefrontal circuit function in AS mouse models. One such readout is behavioral extinction, which has been well described mechanistically and relies upon prefrontal circuits in rodents. Here we report exaggerated operant extinction in male AS model mice, concomitant with enhanced excitability in medial prefrontal neurons from male and female AS model mice. Abnormal behavior was specific to operant extinction, as two other prefrontally dependent tasks (cued fear extinction and visuospatial discrimination) were largely normal in AS model mice. Inducible deletion of Ube3a during adulthood was not sufficient to drive abnormal extinction, supporting the hypothesis that there is an early critical period for development of cognitive phenotypes in AS. This work represents the first formal experimental analysis of prefrontal circuit function in AS, and identifies operant extinction as a useful experimental paradigm for modeling cognitive aspects of AS in mice.SIGNIFICANCE STATEMENT Prefrontal cortex encodes "high-level" cognitive processes. Thus, understanding prefrontal function is critical in neurodevelopmental disorders where cognitive impairment is highly penetrant. Angelman syndrome is a neurodevelopmental disorder associated with speech and motor impairments, an outwardly happy demeanor, and intellectual disability. We describe a behavioral phenotype in a mouse model of Angelman syndrome and related abnormalities in prefrontal cortex function. We hypothesize that robust and reliable prefrontally encoded behavior may be used to model cognitive impairments in Angelman syndrome.
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Sears JC, Broadie K. Fragile X Mental Retardation Protein Regulates Activity-Dependent Membrane Trafficking and Trans-Synaptic Signaling Mediating Synaptic Remodeling. Front Mol Neurosci 2018; 10:440. [PMID: 29375303 PMCID: PMC5770364 DOI: 10.3389/fnmol.2017.00440] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/18/2017] [Indexed: 12/31/2022] Open
Abstract
Fragile X syndrome (FXS) is the leading monogenic cause of autism and intellectual disability. The disease arises through loss of fragile X mental retardation protein (FMRP), which normally exhibits peak expression levels in early-use critical periods, and is required for activity-dependent synaptic remodeling during this transient developmental window. FMRP canonically binds mRNA to repress protein translation, with targets that regulate cytoskeleton dynamics, membrane trafficking, and trans-synaptic signaling. We focus here on recent advances emerging in these three areas from the Drosophila disease model. In the well-characterized central brain mushroom body (MB) olfactory learning/memory circuit, FMRP is required for activity-dependent synaptic remodeling of projection neurons innervating the MB calyx, with function tightly restricted to an early-use critical period. FMRP loss is phenocopied by conditional removal of FMRP only during this critical period, and rescued by FMRP conditional expression only during this critical period. Consistent with FXS hyperexcitation, FMRP loss defects are phenocopied by heightened sensory experience and targeted optogenetic hyperexcitation during this critical period. FMRP binds mRNA encoding Drosophila ESCRTIII core component Shrub (human CHMP4 homolog) to restrict Shrub translation in an activity-dependent mechanism only during this same critical period. Shrub mediates endosomal membrane trafficking, and perturbing Shrub expression is known to interfere with neuronal process pruning. Consistently, FMRP loss and Shrub overexpression targeted to projection neurons similarly causes endosomal membrane trafficking defects within synaptic boutons, and genetic reduction of Shrub strikingly rescues Drosophila FXS model defects. In parallel work on the well-characterized giant fiber (GF) circuit, FMRP limits iontophoretic dye loading into central interneurons, demonstrating an FMRP role controlling core neuronal properties through the activity-dependent repression of translation. In the well-characterized Drosophila neuromuscular junction (NMJ) model, developmental synaptogenesis and activity-dependent synaptic remodeling both require extracellular matrix metalloproteinase (MMP) enzymes interacting with the heparan sulfate proteoglycan (HSPG) glypican dally-like protein (Dlp) to restrict trans-synaptic Wnt signaling, with FXS synaptogenic defects alleviated by both MMP and HSPG reduction. This new mechanistic axis spanning from activity to FMRP to HSPG-dependent MMP regulation modulates activity-dependent synaptogenesis. We discuss future directions for these mechanisms, and intersecting research priorities for FMRP in glial and signaling interactions.
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Affiliation(s)
- James C. Sears
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
- Vanderbilt Kennedy Center for Research on Human Development, Nashville, TN, United States
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, United States
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Selten M, van Bokhoven H, Nadif Kasri N. Inhibitory control of the excitatory/inhibitory balance in psychiatric disorders. F1000Res 2018; 7:23. [PMID: 29375819 PMCID: PMC5760969 DOI: 10.12688/f1000research.12155.1] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/21/2017] [Indexed: 12/21/2022] Open
Abstract
Neuronal networks consist of different types of neurons that all play their own role in order to maintain proper network function. The two main types of neurons segregate in excitatory and inhibitory neurons, which together regulate the flow of information through the network. It has been proposed that changes in the relative strength in these two opposing forces underlie the symptoms observed in psychiatric disorders, including autism and schizophrenia. Here, we review the role of alterations to the function of the inhibitory system as a cause of psychiatric disorders. First, we explore both patient and post-mortem evidence of inhibitory deficiency. We then discuss the function of different interneuron subtypes in the network and focus on the central role of a specific class of inhibitory neurons, parvalbumin-positive interneurons. Finally, we discuss genes known to be affected in different disorders and the effects that mutations in these genes have on the inhibitory system in cortex and hippocampus. We conclude that alterations to the inhibitory system are consistently identified in animal models of psychiatric disorders and, more specifically, that mutations affecting the function of parvalbumin-positive interneurons seem to play a central role in the symptoms observed in these disorders.
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Affiliation(s)
- Martijn Selten
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, New Hunt's House, Guy's Campus, King's College London, London, SE1 1UL, UK.,MRC Centre for Neurodevelopmental Disorders, New Hunt's House, Guy's Campus, King's College London, London, SE1 1UL, UK.,Department of Human Genetics & Department of Cognitive Neuroscience, Radboudumc, Geert Grooteplein 10, Box 9101, 6500 HB Nijmegen, Netherlands.,Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ Nijmegen, Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics & Department of Cognitive Neuroscience, Radboudumc, Geert Grooteplein 10, Box 9101, 6500 HB Nijmegen, Netherlands.,Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ Nijmegen, Netherlands
| | - Nael Nadif Kasri
- Department of Human Genetics & Department of Cognitive Neuroscience, Radboudumc, Geert Grooteplein 10, Box 9101, 6500 HB Nijmegen, Netherlands.,Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ Nijmegen, Netherlands
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Delayed Cryptochrome Degradation Asymmetrically Alters the Daily Rhythm in Suprachiasmatic Clock Neuron Excitability. J Neurosci 2017; 37:7824-7836. [PMID: 28698388 PMCID: PMC5559760 DOI: 10.1523/jneurosci.0691-17.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/01/2017] [Accepted: 06/08/2017] [Indexed: 11/30/2022] Open
Abstract
Suprachiasmatic nuclei (SCN) neurons contain an intracellular molecular circadian clock and the Cryptochromes (CRY1/2), key transcriptional repressors of this molecular apparatus, are subject to post-translational modification through ubiquitination and targeting for proteosomal degradation by the ubiquitin E3 ligase complex. Loss-of-function point mutations in a component of this ligase complex, Fbxl3, delay CRY1/2 degradation, reduce circadian rhythm strength, and lengthen the circadian period by ∼2.5 h. The molecular clock drives circadian changes in the membrane properties of SCN neurons, but it is unclear how alterations in CRY1/2 stability affect SCN neurophysiology. Here we use male and female Afterhours mice which carry the circadian period lengthening loss-of-function Fbxl3Afh mutation and perform patch-clamp recordings from SCN brain slices across the projected day/night cycle. We find that the daily rhythm in membrane excitability in the ventral SCN (vSCN) was enhanced in amplitude and delayed in timing in Fbxl3Afh/Afh mice. At night, vSCN cells from Fbxl3Afh/Afh mice were more hyperpolarized, receiving more GABAergic input than their Fbxl3+/+ counterparts. Unexpectedly, the progression to daytime hyperexcited states was slowed by Afh mutation, whereas the decline to hypoexcited states was accelerated. In long-term bioluminescence recordings, GABAA receptor blockade desynchronized the Fbxl3+/+ but not the Fbxl3Afh/Afh vSCN neuronal network. Further, a neurochemical mimic of the light input pathway evoked larger shifts in molecular clock rhythms in Fbxl3Afh/Afh compared with Fbxl3+/+ SCN slices. These results reveal unanticipated consequences of delaying CRY degradation, indicating that the Afh mutation prolongs nighttime hyperpolarized states of vSCN cells through increased GABAergic synaptic transmission. SIGNIFICANCE STATEMENT The intracellular molecular clock drives changes in SCN neuronal excitability, but it is unclear how mutations affecting post-translational modification of molecular clock proteins influence the temporal expression of SCN neuronal state or intercellular communication within the SCN network. Here we show for the first time, that a mutation that prolongs the stability of key components of the intracellular clock, the cryptochrome proteins, unexpectedly increases in the expression of hypoexcited neuronal state in the ventral SCN at night and enhances hyperpolarization of ventral SCN neurons at this time. This is accompanied by increased GABAergic signaling and by enhanced responsiveness to a neurochemical mimic of the light input pathway to the SCN. Therefore, post-translational modification shapes SCN neuronal state and network properties.
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Steullet P, Cabungcal JH, Coyle J, Didriksen M, Gill K, Grace AA, Hensch TK, LaMantia AS, Lindemann L, Maynard TM, Meyer U, Morishita H, O'Donnell P, Puhl M, Cuenod M, Do KQ. Oxidative stress-driven parvalbumin interneuron impairment as a common mechanism in models of schizophrenia. Mol Psychiatry 2017; 22:936-943. [PMID: 28322275 PMCID: PMC5491690 DOI: 10.1038/mp.2017.47] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/21/2016] [Accepted: 01/17/2017] [Indexed: 02/08/2023]
Abstract
Parvalbumin inhibitory interneurons (PVIs) are crucial for maintaining proper excitatory/inhibitory balance and high-frequency neuronal synchronization. Their activity supports critical developmental trajectories, sensory and cognitive processing, and social behavior. Despite heterogeneity in the etiology across schizophrenia and autism spectrum disorder, PVI circuits are altered in these psychiatric disorders. Identifying mechanism(s) underlying PVI deficits is essential to establish treatments targeting in particular cognition. On the basis of published and new data, we propose oxidative stress as a common pathological mechanism leading to PVI impairment in schizophrenia and some forms of autism. A series of animal models carrying genetic and/or environmental risks relevant to diverse etiological aspects of these disorders show PVI deficits to be all accompanied by oxidative stress in the anterior cingulate cortex. Specifically, oxidative stress is negatively correlated with the integrity of PVIs and the extracellular perineuronal net enwrapping these interneurons. Oxidative stress may result from dysregulation of systems typically affected in schizophrenia, including glutamatergic, dopaminergic, immune and antioxidant signaling. As convergent end point, redox dysregulation has successfully been targeted to protect PVIs with antioxidants/redox regulators across several animal models. This opens up new perspectives for the use of antioxidant treatments to be applied to at-risk individuals, in close temporal proximity to environmental impacts known to induce oxidative stress.
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Affiliation(s)
- P Steullet
- Centre for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly-Lausanne, Switzerland
| | - J-H Cabungcal
- Centre for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly-Lausanne, Switzerland
| | - J Coyle
- Laboratory for Psychiatric and Molecular Neuroscience, Harvard Medical School, McLean Hospital, Belmont, MA, USA
| | - M Didriksen
- Synaptic transmission H. Lundbeck A/S, Valby, Denmark
| | - K Gill
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, USA
| | - A A Grace
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, USA
| | - T K Hensch
- Center for Brain Science, Department of Molecular Cellular Biology, Harvard University, Cambridge, MA USA,FM Kirby Neurobiology Center, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - A-S LaMantia
- George Washington Institute for Neuroscience, The George Washington University, Washington, DC, USA
| | - L Lindemann
- F. Hoffmann-La Roche, Roche Pharmaceutical and Early Development, Neuroscience, Opthalmology & Rare Disease (NORD) DTA, Discovery Neuroscience, Roche Innovation Center Basel, Basel, Switzerland
| | - T M Maynard
- George Washington Institute for Neuroscience, The George Washington University, Washington, DC, USA
| | - U Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
| | - H Morishita
- Center for Brain Science, Department of Molecular Cellular Biology, Harvard University, Cambridge, MA USA,FM Kirby Neurobiology Center, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA,Department of Psychiatry, Neuroscience, and Ophthalmology, Friedman Brain Institute, Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, NY, USA
| | - P O'Donnell
- Neuroscience and Pain Research Unit, BioTherapeutics Research and Development, Pfizer, Cambridge, MA, USA
| | - M Puhl
- Laboratory for Psychiatric and Molecular Neuroscience, Harvard Medical School, McLean Hospital, Belmont, MA, USA
| | - M Cuenod
- Centre for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly-Lausanne, Switzerland
| | - K Q Do
- Centre for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly-Lausanne, Switzerland,Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly-Lausanne CH-1008, Switzerland. E-mail:
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36
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Neural synchronization deficits linked to cortical hyper-excitability and auditory hypersensitivity in fragile X syndrome. Mol Autism 2017; 8:22. [PMID: 28596820 PMCID: PMC5463459 DOI: 10.1186/s13229-017-0140-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 05/04/2017] [Indexed: 12/31/2022] Open
Abstract
Background Studies in the fmr1 KO mouse demonstrate hyper-excitability and increased high-frequency neuronal activity in sensory cortex. These abnormalities may contribute to prominent and distressing sensory hypersensitivities in patients with fragile X syndrome (FXS). The current study investigated functional properties of auditory cortex using a sensory entrainment task in FXS. Methods EEG recordings were obtained from 17 adolescents and adults with FXS and 17 age- and sex-matched healthy controls. Participants heard an auditory chirp stimulus generated using a 1000-Hz tone that was amplitude modulated by a sinusoid linearly increasing in frequency from 0–100 Hz over 2 s. Results Single trial time-frequency analyses revealed decreased gamma band phase-locking to the chirp stimulus in FXS, which was strongly coupled with broadband increases in gamma power. Abnormalities in gamma phase-locking and power were also associated with theta-gamma amplitude-amplitude coupling during the pre-stimulus period and with parent reports of heightened sensory sensitivities and social communication deficits. Conclusions This represents the first demonstration of neural entrainment alterations in FXS patients and suggests that fast-spiking interneurons regulating synchronous high-frequency neural activity have reduced functionality. This reduced ability to synchronize high-frequency neural activity was related to the total power of background gamma band activity. These observations extend findings from fmr1 KO models of FXS, characterize a core pathophysiological aspect of FXS, and may provide a translational biomarker strategy for evaluating promising therapeutics. Electronic supplementary material The online version of this article (doi:10.1186/s13229-017-0140-1) contains supplementary material, which is available to authorized users.
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37
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Lee E, Lee J, Kim E. Excitation/Inhibition Imbalance in Animal Models of Autism Spectrum Disorders. Biol Psychiatry 2017; 81:838-847. [PMID: 27450033 DOI: 10.1016/j.biopsych.2016.05.011] [Citation(s) in RCA: 294] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/02/2016] [Accepted: 05/16/2016] [Indexed: 12/19/2022]
Abstract
Imbalances between excitation and inhibition in synaptic transmission and neural circuits have been implicated in autism spectrum disorders. Excitation and inhibition imbalances are frequently observed in animal models of autism spectrum disorders, and their correction normalizes key autistic-like phenotypes in these animals. These results suggest that excitation and inhibition imbalances may contribute to the development and maintenance of autism spectrum disorders and represent an important therapeutic target.
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Affiliation(s)
- Eunee Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea
| | - Jiseok Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
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38
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Kang JY, Chadchankar J, Vien TN, Mighdoll MI, Hyde TM, Mather RJ, Deeb TZ, Pangalos MN, Brandon NJ, Dunlop J, Moss SJ. Deficits in the activity of presynaptic γ-aminobutyric acid type B receptors contribute to altered neuronal excitability in fragile X syndrome. J Biol Chem 2017; 292:6621-6632. [PMID: 28213518 PMCID: PMC5399111 DOI: 10.1074/jbc.m116.772541] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 02/07/2017] [Indexed: 11/06/2022] Open
Abstract
The behavioral and anatomical deficits seen in fragile X syndrome (FXS) are widely believed to result from imbalances in the relative strengths of excitatory and inhibitory neurotransmission. Although modified neuronal excitability is thought to be of significance, the contribution that alterations in GABAergic inhibition play in the pathophysiology of FXS are ill defined. Slow sustained neuronal inhibition is mediated by γ-aminobutyric acid type B (GABAB) receptors, which are heterodimeric G-protein-coupled receptors constructed from R1a and R2 or R1b and R2 subunits. Via the activation of Gi/o, they limit cAMP accumulation, diminish neurotransmitter release, and induce neuronal hyperpolarization. Here we reveal that selective deficits in R1a subunit expression are seen in Fmr1 knock-out mice (KO) mice, a widely used animal model of FXS, but the levels of the respective mRNAs were unaffected. Similar trends of R1a expression were seen in a subset of FXS patients. GABAB receptors (GABABRs) exert powerful pre- and postsynaptic inhibitory effects on neurotransmission. R1a-containing GABABRs are believed to mediate presynaptic inhibition in principal neurons. In accordance with this result, deficits in the ability of GABABRs to suppress glutamate release were seen in Fmr1-KO mice. In contrast, the ability of GABABRs to suppress GABA release and induce postsynaptic hyperpolarization was unaffected. Significantly, this deficit contributes to the pathophysiology of FXS as the GABABR agonist (R)-baclofen rescued the imbalances between excitatory and inhibitory neurotransmission evident in Fmr1-KO mice. Collectively, our results provided evidence that selective deficits in the activity of presynaptic GABABRs contribute to the pathophysiology of FXS.
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Affiliation(s)
- Ji-Yong Kang
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Jayashree Chadchankar
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Thuy N Vien
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | | | - Thomas M Hyde
- the Lieber Institute for Brain Development and
- Departments of Neurology and Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Robert J Mather
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
| | - Tarek Z Deeb
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Menelas N Pangalos
- Innovative Medicines and Early Development, AstraZeneca, Melbourn Science Park, Cambridge Road, Royston Herts SG8 6EE, United Kingdom, and
| | - Nicholas J Brandon
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
| | - John Dunlop
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
| | - Stephen J Moss
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111,
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
- the Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E 6BT, United Kingdom
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39
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Wang J, Ethridge LE, Mosconi MW, White SP, Binder DK, Pedapati EV, Erickson CA, Byerly MJ, Sweeney JA. A resting EEG study of neocortical hyperexcitability and altered functional connectivity in fragile X syndrome. J Neurodev Disord 2017; 9:11. [PMID: 28316753 PMCID: PMC5351111 DOI: 10.1186/s11689-017-9191-z] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 02/10/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Cortical hyperexcitability due to abnormal fast-spiking inhibitory interneuron function has been documented in fmr1 KO mice, a mouse model of the fragile X syndrome which is the most common single gene cause of autism and intellectual disability. METHODS We collected resting state dense-array electroencephalography data from 21 fragile X syndrome (FXS) patients and 21 age-matched healthy participants. RESULTS FXS patients exhibited greater gamma frequency band power, which was correlated with social and sensory processing difficulties. Second, FXS patients showed increased spatial spreading of phase-synchronized high frequency neural activity in the gamma band. Third, we observed increased negative theta-to-gamma but decreased alpha-to-gamma band amplitude coupling, and the level of increased theta power was inversely related to the level of resting gamma power in FXS. CONCLUSIONS Increased theta band power and coupling from frontal sources may represent a mechanism providing compensatory inhibition of high-frequency gamma band activity, potentially contributing to the widely varying level of neurophysiological and behavioral abnormalities and treatment response seen in full-mutation FXS patients. These findings extend preclinical observations and provide new mechanistic insights into brain alterations and their variability across FXS patients. Electrophysiological measures may provide useful translational biomarkers for advancing drug development and individualizing treatments for neurodevelopmental disorders with associated neuronal hyperexcitability.
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Affiliation(s)
- Jun Wang
- Department of Psychology, Zhejiang Normal University, 688 Yingbin Road, Jinhua, Zhejiang China 321004
| | - Lauren E. Ethridge
- Department of Pediatrics, Section of Developmental and Behavioral Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
- Department of Psychology, University of Oklahoma, Norman, OK USA
| | - Matthew W. Mosconi
- Clinical Child Psychology Program and Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS USA
| | - Stormi P. White
- Department of Psychiatry, Center for Autism and Developmental Disabilities, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Devin K. Binder
- Center for Glial-Neuronal Interactions, Neuroscience Graduate Program, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA USA
| | - Ernest V. Pedapati
- Department of Psychiatry and Behavioral Neuroscience and Division of Psychiatry, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH USA
| | - Craig A. Erickson
- Department of Psychiatry and Behavioral Neuroscience and Division of Psychiatry, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH USA
| | - Matthew J. Byerly
- Center for Mental Health Research and Recovery, Montana State University, Bozeman, MT USA
| | - John A. Sweeney
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH USA
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40
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Petrov AM, Kasimov MR, Zefirov AL. Cholesterol in the Pathogenesis of Alzheimer's, Parkinson's Diseases and Autism: Link to Synaptic Dysfunction. Acta Naturae 2017; 9:26-37. [PMID: 28461971 PMCID: PMC5406657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Indexed: 11/30/2022] Open
Abstract
In our previous review, we described brain cholesterol metabolism in control conditions and in the case of some rare neurological pathologies linked to defects in the genes which are directly involved in the synthesis and/or traffic of cholesterol. Here, we have analyzed disruptions in cholesterol homeostasis in widespread neurodegenerative diseases (Alzheimer's and Parkinson's diseases) and autism spectrum disorders. We particularly focused on the synaptic dysfunctions that could arise from changes in both membrane cholesterol availability and oxysterol production. Notably, alterations in the brain cholesterol metabolism and neurotransmission occur in the early stages of these pathologies and the polymorphism of the genes associated with cholesterol homeostasis and synaptic communication affects the risk of onset and severity of these diseases. In addition, pharmacological and genetic manipulations of brain cholesterol homeostasis in animal models frequently have marked effects on the progression of neurodegenerative diseases. Thus, the development of Alzheimer's, Parkinson's and autism spectrum disorders may be partially associated with an imbalance of cholesterol homeostasis that leads to changes in the membrane cholesterol and oxysterol levels that, in turn, modulates key steps in the synaptic transmission.
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Affiliation(s)
- A. M. Petrov
- Kazan State Medical University, Normal Physiology department, Butlerova str. 49, Kazan, 420012, Russia
| | - M. R. Kasimov
- Kazan State Medical University, Normal Physiology department, Butlerova str. 49, Kazan, 420012, Russia
| | - A. L. Zefirov
- Kazan State Medical University, Normal Physiology department, Butlerova str. 49, Kazan, 420012, Russia
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41
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Fragile X mental retardation protein knockdown in the developing Xenopus tadpole optic tectum results in enhanced feedforward inhibition and behavioral deficits. Neural Dev 2016; 11:14. [PMID: 27503008 PMCID: PMC4977860 DOI: 10.1186/s13064-016-0069-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/03/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Fragile X Syndrome is the leading monogenetic cause of autism and most common form of intellectual disability. Previous studies have implicated changes in dendritic spine architecture as the primary result of loss of Fragile X Mental Retardation Protein (FMRP), but recent work has shown that neural proliferation is decreased and cell death is increased with either loss of FMRP or overexpression of FMRP. The purpose of this study was to investigate the effects of loss of FMRP on behavior and cellular activity. METHODS We knocked down FMRP expression using morpholino oligos in the optic tectum of Xenopus laevis tadpoles and performed a series of behavioral and electrophysiological assays. We investigated visually guided collision avoidance, schooling, and seizure propensity. Using single cell electrophysiology, we assessed intrinsic excitability and synaptic connectivity of tectal neurons. RESULTS We found that FMRP knockdown results in decreased swimming speed, reduced schooling behavior and decreased seizure severity. In single cells, we found increased inhibition relative to excitation in response to sensory input. CONCLUSIONS Our results indicate that the electrophysiological development of single cells in the absence of FMRP is largely unaffected despite the large neural proliferation defect. The changes in behavior are consistent with an increase in inhibition, which could be due to either changes in cell number or altered inhibitory drive, and indicate that FMRP can play a significant role in neural development much earlier than previously thought.
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42
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Neuron class-specific requirements for Fragile X Mental Retardation Protein in critical period development of calcium signaling in learning and memory circuitry. Neurobiol Dis 2016; 89:76-87. [PMID: 26851502 DOI: 10.1016/j.nbd.2016.02.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/27/2016] [Accepted: 02/02/2016] [Indexed: 01/22/2023] Open
Abstract
Neural circuit optimization occurs through sensory activity-dependent mechanisms that refine synaptic connectivity and information processing during early-use developmental critical periods. Fragile X Mental Retardation Protein (FMRP), the gene product lost in Fragile X syndrome (FXS), acts as an activity sensor during critical period development, both as an RNA-binding translation regulator and channel-binding excitability regulator. Here, we employ a Drosophila FXS disease model to assay calcium signaling dynamics with a targeted transgenic GCaMP reporter during critical period development of the mushroom body (MB) learning/memory circuit. We find FMRP regulates depolarization-induced calcium signaling in a neuron-specific manner within this circuit, suppressing activity-dependent calcium transients in excitatory cholinergic MB input projection neurons and enhancing calcium signals in inhibitory GABAergic MB output neurons. Both changes are restricted to the developmental critical period and rectified at maturity. Importantly, conditional genetic (dfmr1) rescue of null mutants during the critical period corrects calcium signaling defects in both neuron classes, indicating a temporally restricted FMRP requirement. Likewise, conditional dfmr1 knockdown (RNAi) during the critical period replicates constitutive null mutant defects in both neuron classes, confirming cell-autonomous requirements for FMRP in developmental regulation of calcium signaling dynamics. Optogenetic stimulation during the critical period enhances depolarization-induced calcium signaling in both neuron classes, but this developmental change is eliminated in dfmr1 null mutants, indicating the activity-dependent regulation requires FMRP. These results show FMRP shapes neuron class-specific calcium signaling in excitatory vs. inhibitory neurons in developing learning/memory circuitry, and that FMRP mediates activity-dependent regulation of calcium signaling specifically during the early-use critical period.
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43
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Bhattacharyya A, Zhao X. Human pluripotent stem cell models of Fragile X syndrome. Mol Cell Neurosci 2015; 73:43-51. [PMID: 26640241 DOI: 10.1016/j.mcn.2015.11.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 11/03/2015] [Accepted: 11/25/2015] [Indexed: 01/18/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and autism. The causal mutation in FXS is a trinucleotide CGG repeat expansion in the FMR1 gene that leads to human specific epigenetic silencing and loss of Fragile X Mental Retardation Protein (FMRP) expression. Human pluripotent stem cells (PSCs), including human embryonic stem cells (ESCs) and particularly induced PSCs (iPSCs), offer a model system to reveal cellular and molecular events underlying human neuronal development and function in FXS. Human FXS PSCs have been established and have provided insight into the epigenetic silencing of the FMR1 gene as well as aspects of neuronal development.
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Affiliation(s)
- Anita Bhattacharyya
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, United States.
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, United States.
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44
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Abstract
Intellectual disability, autism spectrum disorder, and epilepsy are prime examples of neurodevelopmental disorders that collectively affect a significant percentage of the world population. Recent technological breakthroughs allowed the elucidation of the genetic causes of many of these disorders. As neurodevelopmental disorders are genetically heterogeneous, the development of rational therapy is extremely challenging. Fortunately, many causative genes are interconnected and cluster in specific cellular pathways. Targeting a common node in such a network would allow us to interfere with a series of related neurodevelopmental disorders at once. Here, we argue that the GABAergic system is disturbed in many neurodevelopmental disorders, including fragile X syndrome, Rett syndrome, and Dravet syndrome, and is a key candidate target for therapeutic intervention. Many drugs that modulate the GABAergic system have already been tested in animal models with encouraging outcomes and are readily available for clinical trials.
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Affiliation(s)
- Sien Braat
- Department of Medical Genetics, University of Antwerp, Prins Boudewijnlaan 43, 2650 Edegem, Belgium
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Prins Boudewijnlaan 43, 2650 Edegem, Belgium.
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45
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Fmr1 deficiency promotes age-dependent alterations in the cortical synaptic proteome. Proc Natl Acad Sci U S A 2015; 112:E4697-706. [PMID: 26307763 DOI: 10.1073/pnas.1502258112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Fragile X syndrome (FXS) is an X-linked neurodevelopmental disorder characterized by severe intellectual disability and other symptoms including autism. Although caused by the silencing of a single gene, Fmr1 (fragile X mental retardation 1), the complexity of FXS pathogenesis is amplified because the encoded protein, FMRP, regulates the activity-dependent translation of numerous mRNAs. Although the mRNAs that associate with FMRP have been extensively studied, little is known regarding the proteins whose expression levels are altered, directly or indirectly, by loss of FMRP during brain development. Here we systematically measured protein expression in neocortical synaptic fractions from Fmr1 knockout (KO) and wild-type (WT) mice at both adolescent and adult stages. Although hundreds of proteins are up-regulated in the absence of FMRP in young mice, this up-regulation is largely diminished in adulthood. Up-regulated proteins included previously unidentified as well as known targets involved in synapse formation and function and brain development and others linked to intellectual disability and autism. Comparison with putative FMRP target mRNAs and autism susceptibility genes revealed substantial overlap, consistent with the idea that the autism endophenotype of FXS is due to a "multiple hit" effect of FMRP loss, particularly within the PSD95 interactome. Through studies of de novo protein synthesis in primary cortical neurons from KO and WT mice, we found that neurons lacking FMRP produce nascent proteins at higher rates, many of which are synaptic proteins and encoded by FMRP target mRNAs. Our results provide a greatly expanded view of protein changes in FXS and identify age-dependent effects of FMRP in shaping the neuronal proteome.
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46
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Takano T. Interneuron Dysfunction in Syndromic Autism: Recent Advances. Dev Neurosci 2015; 37:467-75. [PMID: 26183392 DOI: 10.1159/000434638] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/27/2015] [Indexed: 11/19/2022] Open
Abstract
Autism is an extremely heterogeneous disorder, but its frequent cooccurrence with epilepsy leads to speculation that there may be common mechanisms associated with these disorders. Inhibitory interneurons are considered to be the main cellular elements that control hyperexcitability in the brain, and interneuron dysfunction can cause pathological hyperexcitability linked to seizure susceptibility or epilepsy. This review summarizes some of the recent advances that support the relationship between interneuron dysfunction and cognitive impairment in human syndromic autism, with particular reference to the pathophysiological findings of murine experimental models of autism. Alterations in x03B3;-aminobutyric acid (GABA)ergic circuits include a wide variety of neurobiological dysfunctions and do not simply involve the loss or gain of any given type of inhibitory mechanism. The characteristics of interneuron dysfunction in each murine model of autism differ for each syndrome, and these diversities may be due to differences in genetic backgrounds or some other currently unknown variances. Future studies should give us a greater understanding of the involvement of different classes of GABAergic interneurons and allow us to define the relationship between the precise pathophysiological mechanisms and the corresponding clinical phenotypes in autism.
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Affiliation(s)
- Tomoyuki Takano
- Department of Pediatrics, Shiga University of Medical Science, Otsu, Japan
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47
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Weisz ED, Monyak RE, Jongens TA. Deciphering discord: How Drosophila research has enhanced our understanding of the importance of FMRP in different spatial and temporal contexts. Exp Neurol 2015; 274:14-24. [PMID: 26026973 DOI: 10.1016/j.expneurol.2015.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/18/2015] [Accepted: 05/23/2015] [Indexed: 01/06/2023]
Abstract
Fragile X Syndrome (FXS) is the most common heritable form of intellectual impairment as well as the leading monogenetic cause of autism. In addition to its canonical definition as a neurodevelopmental disease, recent findings in the clinic suggest that FXS is a systemic disorder that is characterized by a variety of heterogeneous phenotypes. Efforts to study FXS pathogenesis have been aided by the development and characterization of animal models of the disease. Research efforts in Drosophila melanogaster have revealed key insights into the mechanistic underpinnings of FXS. While much remains unknown, it is increasingly apparent that FXS involves a myriad of spatially and temporally specific alterations in cellular function. Consequently, the literature is filled with numerous discordant findings. Researchers and clinicians alike must be cognizant of this dissonance, as it will likely be important for the design of preclinical studies to assess the efficacy of therapeutic strategies to improve the lives of FXS patients.
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Affiliation(s)
- Eliana D Weisz
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Rachel E Monyak
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Thomas A Jongens
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
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48
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Wang H, Doering LC. Autism spectrum disorders: emerging mechanisms and mechanism-based treatment. Front Cell Neurosci 2015; 9:183. [PMID: 26029053 PMCID: PMC4428121 DOI: 10.3389/fncel.2015.00183] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 04/27/2015] [Indexed: 12/27/2022] Open
Affiliation(s)
- Hansen Wang
- Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Laurie C Doering
- Department of Pathology and Molecular Medicine, Faculty of Health Sciences, McMaster University Hamilton, ON, Canada
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49
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Devitt NM, Gallagher L, Reilly RB. Autism Spectrum Disorder (ASD) and Fragile X Syndrome (FXS): Two Overlapping Disorders Reviewed through Electroencephalography-What Can be Interpreted from the Available Information? Brain Sci 2015; 5:92-117. [PMID: 25826237 PMCID: PMC4493458 DOI: 10.3390/brainsci5020092] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/11/2015] [Accepted: 03/17/2015] [Indexed: 02/07/2023] Open
Abstract
Autism Spectrum Disorder (ASD) and Fragile X syndrome (FXS) are neurodevelopmental disorders with different but potentially related neurobiological underpinnings, which exhibit significant overlap in their behavioural symptoms. FXS is a neurogenetic disorder of known cause whereas ASD is a complex genetic disorder, with both rare and common genetic risk factors and likely genetic and environmental interaction effects. A comparison of the phenotypic presentation of the two disorders may highlight those symptoms that are more likely to be under direct genetic control, for example in FXS as opposed to shared symptoms that are likely to be under the control of multiple mechanisms. This review is focused on the application and analysis of electroencephalography data (EEG) in ASD and FXS. Specifically, Event Related Potentials (ERP) and resting state studies (rEEG) studies investigating ASD and FXS cohorts are compared. This review explores the electrophysiological similarities and differences between the two disorders in addition to the potentially associated neurobiological mechanisms at play. A series of pertinent research questions which are suggested in the literature are also posed within the review.
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Affiliation(s)
- Niamh Mc Devitt
- School of Medicine, Trinity College, the University of Dublin, Dublin, Ireland.
- Trinity Centre for Bioengineering, Trinity College Dublin, the University of Dublin, Dublin, Ireland.
| | - Louise Gallagher
- School of Medicine, Trinity College, the University of Dublin, Dublin, Ireland.
- Trinity College Institute for Neuroscience, Trinity College Dublin, the University of Dublin, Dublin, Ireland.
- Department of Psychiatry, Trinity College Dublin, the University of Dublin, Dublin, Ireland.
- Institute of Molecular Medicine, Trinity Centre for Health Sciences, St James' Hospital, Dublin, Ireland.
- Linn Dara Child and Adolescent Mental Health Services, Cherry Orchard Hospital Dublin 10, Dublin, Ireland.
| | - Richard B Reilly
- School of Medicine, Trinity College, the University of Dublin, Dublin, Ireland.
- Trinity Centre for Bioengineering, Trinity College Dublin, the University of Dublin, Dublin, Ireland.
- Trinity College Institute for Neuroscience, Trinity College Dublin, the University of Dublin, Dublin, Ireland.
- School of Engineering, Trinity College Dublin, the University of Dublin, Dublin, Ireland.
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