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Juarez P, Salcedo-Arellano MJ, Dufour B, Martinez-Cerdeño V. Fragile X cortex is characterized by decreased parvalbumin-expressing interneurons. Cereb Cortex 2024; 34:bhae103. [PMID: 38521994 PMCID: PMC10960956 DOI: 10.1093/cercor/bhae103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/25/2024] Open
Abstract
Fragile X syndrome is a genetic neurodevelopmental disorder caused by a mutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene in the X chromosome. Many fragile X syndrome cases present with autism spectrum disorder and fragile X syndrome cases account for up to 5% of all autism spectrum disorder cases. The cellular composition of the fragile X syndrome cortex is not well known. We evaluated alterations in the number of Calbindin, Calretinin, and Parvalbumin expressing interneurons across 5 different cortical areas, medial prefrontal cortex (BA46), primary somatosensory cortex (BA3), primary motor cortex (BA4), superior temporal cortex (BA22), and anterior cingulate cortex (BA24) of fragile X syndrome and neurotypical brains. Compared with neurotypical cases, fragile X syndrome brains displayed a significant reduction in the number of PV+ interneurons in all areas and of CR+ interneurons in BA22 and BA3. The number of CB+ interneurons did not differ. These findings are the first to demonstrate that fragile X syndrome brains are characterized by cortical wide PV+ interneuron deficits across multiple cortical areas. These add to the idea that deficits in PV+ interneurons could disrupt the cortical balance and promote clinical deficits in fragile X syndrome patients and help to develop novel therapies for neurodevelopmental disorders like fragile X syndrome and autism spectrum disorder.
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Affiliation(s)
- Pablo Juarez
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern CaliforniaSacramento, CA 95817, United States
| | - Maria Jimena Salcedo-Arellano
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern CaliforniaSacramento, CA 95817, United States
- MIND Institute, University of California, Davis, Sacramento, CA 95817, United States
| | - Brett Dufour
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern CaliforniaSacramento, CA 95817, United States
- MIND Institute, University of California, Davis, Sacramento, CA 95817, United States
| | - Veronica Martinez-Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern CaliforniaSacramento, CA 95817, United States
- MIND Institute, University of California, Davis, Sacramento, CA 95817, United States
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2
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Farhoomand F, Delaney KR. Long-term cortical plasticity following sensory deprivation is reduced in male Rett model mice. Somatosens Mot Res 2023; 40:133-140. [PMID: 36565289 DOI: 10.1080/08990220.2022.2158799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 12/08/2022] [Indexed: 12/25/2022]
Abstract
PURPOSE/AIM Rett (RTT) syndrome, a neurodevelopmental disorder, results from loss-of-function mutations in methyl-CpG-binding protein 2. We studied activity-dependent plasticity induced by sensory deprivation via whisker trimming in early symptomatic male mutant mice to assess neural rewiring capability. METHODS One whisker was trimmed for 0-14 days and intrinsic optical imaging of the transient reduction of brain blood oxygenation resulting from neural activation by 1 second of wiggling of the whisker stump was compared to that of an untrimmed control whisker. RESULTS Cortical evoked responses to wiggling a non-trimmed whisker were constant for 14 days, reduced for a trimmed whisker by 49.0 ± 4.3% in wild type (n = 14) but by only 22.7 ± 4.6% in mutant (n = 18, p = 0.001). CONCLUSION As the reduction in neural activation following sensory deprivation in whisker barrel cortex is known to be dependent upon evoked and basal neural activity, impairment of cortical re-wiring following whisker trimming provides a paradigm suitable to explore mechanisms underlying deficiencies in the establishment and maintenance of synapses in RTT, which can be potentially targeted by therapeutics.
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Affiliation(s)
| | - Kerry R Delaney
- Department of Biology, University of Victoria, Victoria, B.C, Canada
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3
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Odabasi Y, Yanasik S, Saglam-Metiner P, Kaymaz Y, Yesil-Celiktas O. Comprehensive Transcriptomic Investigation of Rett Syndrome Reveals Increasing Complexity Trends from Induced Pluripotent Stem Cells to Neurons with Implications for Enriched Pathways. ACS OMEGA 2023; 8:44148-44162. [PMID: 38027357 PMCID: PMC10666228 DOI: 10.1021/acsomega.3c06448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/19/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023]
Abstract
Rett syndrome (RTT) is a rare genetic neurodevelopmental disorder that has no cure apart from symptomatic treatments. While intense research efforts are required to fulfill this unmet need, the fundamental challenge is to obtain sufficient patient data. In this study, we used human transcriptomic data of four different sample types from RTT patients including induced pluripotent stem cells, differentiated neural progenitor cells, differentiated neurons, and postmortem brain tissues with an increasing in vivo-like complexity to unveil specific trends in gene expressions across the samples. Based on DEG analysis, we identified F8A3, CNTN6, RPE65, and COL19A1 to have differential expression levels in three sample types and also observed previously reported genes such as MECP2, FOXG1, CACNA1G, SATB2, GABBR2, MEF2C, KCNJ10, and CUX2 in our study. Considering the significantly enriched pathways for each sample type, we observed a consistent increase in numbers from iPSCs to NEUs where MECP2 displayed profound effects. We also validated our GSEA results by using single-cell RNA-seq data. In WGCNA, we elicited a connection among MECP2, TNRC6A, and HOXA5. Our findings highlight the utility of transcriptomic analyses to determine genes that might lead to therapeutic strategies.
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Affiliation(s)
- Yusuf
Caglar Odabasi
- Department of Bioengineering,
Faculty of Engineering, Ege University, Izmir 35100, Turkey
| | - Sena Yanasik
- Department of Bioengineering,
Faculty of Engineering, Ege University, Izmir 35100, Turkey
| | - Pelin Saglam-Metiner
- Department of Bioengineering,
Faculty of Engineering, Ege University, Izmir 35100, Turkey
| | - Yasin Kaymaz
- Department of Bioengineering,
Faculty of Engineering, Ege University, Izmir 35100, Turkey
| | - Ozlem Yesil-Celiktas
- Department of Bioengineering,
Faculty of Engineering, Ege University, Izmir 35100, Turkey
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4
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Cording KR, Bateup HS. Altered motor learning and coordination in mouse models of autism spectrum disorder. Front Cell Neurosci 2023; 17:1270489. [PMID: 38026686 PMCID: PMC10663323 DOI: 10.3389/fncel.2023.1270489] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/25/2023] [Indexed: 12/01/2023] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with increasing prevalence. Over 1,000 risk genes have now been implicated in ASD, suggesting diverse etiology. However, the diagnostic criteria for the disorder still comprise two major behavioral domains - deficits in social communication and interaction, and the presence of restricted and repetitive patterns of behavior (RRBs). The RRBs associated with ASD include both stereotyped repetitive movements and other motor manifestations including changes in gait, balance, coordination, and motor skill learning. In recent years, the striatum, the primary input center of the basal ganglia, has been implicated in these ASD-associated motor behaviors, due to the striatum's role in action selection, motor learning, and habit formation. Numerous mouse models with mutations in ASD risk genes have been developed and shown to have alterations in ASD-relevant behaviors. One commonly used assay, the accelerating rotarod, allows for assessment of both basic motor coordination and motor skill learning. In this corticostriatal-dependent task, mice walk on a rotating rod that gradually increases in speed. In the extended version of this task, mice engage striatal-dependent learning mechanisms to optimize their motor routine and stay on the rod for longer periods. This review summarizes the findings of studies examining rotarod performance across a range of ASD mouse models, and the resulting implications for the involvement of striatal circuits in ASD-related motor behaviors. While performance in this task is not uniform across mouse models, there is a cohort of models that show increased rotarod performance. A growing number of studies suggest that this increased propensity to learn a fixed motor routine may reflect a common enhancement of corticostriatal drive across a subset of mice with mutations in ASD-risk genes.
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Affiliation(s)
- Katherine R. Cording
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | - Helen S. Bateup
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Molecular and Cell Biology Department, University of California, Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
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5
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Monday HR, Wang HC, Feldman DE. Circuit-level theories for sensory dysfunction in autism: convergence across mouse models. Front Neurol 2023; 14:1254297. [PMID: 37745660 PMCID: PMC10513044 DOI: 10.3389/fneur.2023.1254297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/14/2023] [Indexed: 09/26/2023] Open
Abstract
Individuals with autism spectrum disorder (ASD) exhibit a diverse range of behavioral features and genetic backgrounds, but whether different genetic forms of autism involve convergent pathophysiology of brain function is unknown. Here, we analyze evidence for convergent deficits in neural circuit function across multiple transgenic mouse models of ASD. We focus on sensory areas of neocortex, where circuit differences may underlie atypical sensory processing, a central feature of autism. Many distinct circuit-level theories for ASD have been proposed, including increased excitation-inhibition (E-I) ratio and hyperexcitability, hypofunction of parvalbumin (PV) interneuron circuits, impaired homeostatic plasticity, degraded sensory coding, and others. We review these theories and assess the degree of convergence across ASD mouse models for each. Behaviorally, our analysis reveals that innate sensory detection behavior is heightened and sensory discrimination behavior is impaired across many ASD models. Neurophysiologically, PV hypofunction and increased E-I ratio are prevalent but only rarely generate hyperexcitability and excess spiking. Instead, sensory tuning and other aspects of neural coding are commonly degraded and may explain impaired discrimination behavior. Two distinct phenotypic clusters with opposing neural circuit signatures are evident across mouse models. Such clustering could suggest physiological subtypes of autism, which may facilitate the development of tailored therapeutic approaches.
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Affiliation(s)
- Hannah R. Monday
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | | | - Daniel E. Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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6
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Pilotto F, Douthwaite C, Diab R, Ye X, Al Qassab Z, Tietje C, Mounassir M, Odriozola A, Thapa A, Buijsen RAM, Lagache S, Uldry AC, Heller M, Müller S, van Roon-Mom WMC, Zuber B, Liebscher S, Saxena S. Early molecular layer interneuron hyperactivity triggers Purkinje neuron degeneration in SCA1. Neuron 2023; 111:2523-2543.e10. [PMID: 37321222 PMCID: PMC10431915 DOI: 10.1016/j.neuron.2023.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/17/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023]
Abstract
Toxic proteinaceous deposits and alterations in excitability and activity levels characterize vulnerable neuronal populations in neurodegenerative diseases. Using in vivo two-photon imaging in behaving spinocerebellar ataxia type 1 (Sca1) mice, wherein Purkinje neurons (PNs) degenerate, we identify an inhibitory circuit element (molecular layer interneurons [MLINs]) that becomes prematurely hyperexcitable, compromising sensorimotor signals in the cerebellum at early stages. Mutant MLINs express abnormally elevated parvalbumin, harbor high excitatory-to-inhibitory synaptic density, and display more numerous synaptic connections on PNs, indicating an excitation/inhibition imbalance. Chemogenetic inhibition of hyperexcitable MLINs normalizes parvalbumin expression and restores calcium signaling in Sca1 PNs. Chronic inhibition of mutant MLINs delayed PN degeneration, reduced pathology, and ameliorated motor deficits in Sca1 mice. Conserved proteomic signature of Sca1 MLINs, shared with human SCA1 interneurons, involved the higher expression of FRRS1L, implicated in AMPA receptor trafficking. We thus propose that circuit-level deficits upstream of PNs are one of the main disease triggers in SCA1.
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Affiliation(s)
- Federica Pilotto
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Christopher Douthwaite
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Rim Diab
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - XiaoQian Ye
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Zahraa Al Qassab
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Christoph Tietje
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Meriem Mounassir
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | | | - Aishwarya Thapa
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Ronald A M Buijsen
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Sophie Lagache
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Stefan Müller
- Flow Cytometry and Cell sorting, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | | | - Benoît Zuber
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Sabine Liebscher
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; University Hospital Cologne, Deptartment of Neurology, Cologne, Germany.
| | - Smita Saxena
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland.
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7
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Mykins M, Layo-Carris D, Dunn LR, Skinner DW, McBryar AH, Perez S, Shultz TR, Willems A, Lau BYB, Hong T, Krishnan K. Wild-type MECP2 expression coincides with age-dependent sensory phenotypes in a female mouse model for Rett syndrome. J Neurosci Res 2023; 101:1236-1258. [PMID: 37026482 PMCID: PMC10332853 DOI: 10.1002/jnr.25190] [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: 09/14/2022] [Revised: 02/07/2023] [Accepted: 03/12/2023] [Indexed: 04/08/2023]
Abstract
Rett syndrome is characterized by an early period of typical development and then, regression of learned motor and speech skills in girls. Loss of MECP2 protein is thought to cause Rett syndrome phenotypes. The specific underlying mechanisms from typical developmental trajectory to regression features throughout life are unclear. Lack of established timelines to study the molecular, cellular, and behavioral features of regression in female mouse models is a major contributing factor. Due to random X-chromosome inactivation, female patients with Rett syndrome and female mouse models for Rett syndrome (Mecp2Heterozygous , Het) express a functional copy of wild-type MECP2 protein in approximately half of all cells. As MECP2 expression is regulated during early postnatal development and experience, we characterized the expression of wild-type MECP2 in the primary somatosensory cortex of female Het mice. Here, we report increased MECP2 levels in non-parvalbumin-positive neurons of 6-week-old adolescent Het relative to age-matched wild-type controls, while also displaying typical levels of perineuronal net expression in the barrel field subregion of the primary somatosensory cortex, mild tactile sensory perception deficits, and efficient pup retrieval behavior. In contrast, 12-week-old adult Het express MECP2 at levels similar to age-matched wild-type mice, show increased perineuronal net expression in the cortex, and display significant tactile sensory perception deficits. Thus, we have identified a set of behavioral metrics and the cellular substrates to study regression during a specific time in the female Het mouse model, which coincides with changes in wild-type MECP2 expression. We speculate that the precocious increase in MECP2 expression within specific cell types of adolescent Het may provide compensatory benefits at the behavioral level, while the inability to further increase MECP2 levels leads to regressive behavioral phenotypes over time.
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Affiliation(s)
- Michael Mykins
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Dana Layo-Carris
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Logan Reid Dunn
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - David Wilson Skinner
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Alexandra Hart McBryar
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Sarah Perez
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Trinity Rose Shultz
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Andrew Willems
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Billy You Bun Lau
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Tian Hong
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Keerthi Krishnan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
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8
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Rahn RM, Yen A, Chen S, Gaines SH, Bice AR, Brier LM, Swift RG, Lee L, Maloney SE, Culver JP, Dougherty JD. Mecp2 deletion results in profound alterations of developmental and adult functional connectivity. Cereb Cortex 2023; 33:7436-7453. [PMID: 36897048 PMCID: PMC10267622 DOI: 10.1093/cercor/bhad050] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 03/11/2023] Open
Abstract
As a regressive neurodevelopmental disorder with a well-established genetic cause, Rett syndrome and its Mecp2 loss-of-function mouse model provide an excellent opportunity to define potentially translatable functional signatures of disease progression, as well as offer insight into the role of Mecp2 in functional circuit development. Thus, we applied widefield optical fluorescence imaging to assess mesoscale calcium functional connectivity (FC) in the Mecp2 cortex both at postnatal day (P)35 in development and during the disease-related decline. We found that FC between numerous cortical regions was disrupted in Mecp2 mutant males both in juvenile development and early adulthood. Female Mecp2 mice displayed an increase in homotopic contralateral FC in the motor cortex at P35 but not in adulthood, where instead more posterior parietal regions were implicated. An increase in the amplitude of connection strength, both with more positive correlations and more negative anticorrelations, was observed across the male cortex in numerous functional regions. Widespread rescue of MeCP2 protein in GABAergic neurons rescued none of these functional deficits, nor, surprisingly, the expected male lifespan. Altogether, the female results identify early signs of disease progression, while the results in males indicate MeCP2 protein is required for typical FC in the brain.
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Affiliation(s)
- Rachel M Rahn
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Allen Yen
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Siyu Chen
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Seana H Gaines
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Lindsey M Brier
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Raylynn G Swift
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - LeiLani Lee
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Susan E Maloney
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Intellectual and Developmental Disabilities Research Center, 660 South Euclid Avenue, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Joseph P Culver
- Department of Radiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Physics, Washington University School of Arts and Sciences, 1 Brookings Drive, St. Louis, MO 63130, United States
- Department of Biomedical Engineering, Washington University School of Engineering, 1 Brookings Drive, St. Louis, MO 63130, United States
| | - Joseph D Dougherty
- Department of Genetics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, United States
- Intellectual and Developmental Disabilities Research Center, 660 South Euclid Avenue, Washington University School of Medicine, St. Louis, MO 63110, United States
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9
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Transition from Animal-Based to Human Induced Pluripotent Stem Cells (iPSCs)-Based Models of Neurodevelopmental Disorders: Opportunities and Challenges. Cells 2023; 12:cells12040538. [PMID: 36831205 PMCID: PMC9954744 DOI: 10.3390/cells12040538] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/25/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023] Open
Abstract
Neurodevelopmental disorders (NDDs) arise from the disruption of highly coordinated mechanisms underlying brain development, which results in impaired sensory, motor and/or cognitive functions. Although rodent models have offered very relevant insights to the field, the translation of findings to clinics, particularly regarding therapeutic approaches for these diseases, remains challenging. Part of the explanation for this failure may be the genetic differences-some targets not being conserved between species-and, most importantly, the differences in regulation of gene expression. This prompts the use of human-derived models to study NDDS. The generation of human induced pluripotent stem cells (hIPSCs) added a new suitable alternative to overcome species limitations, allowing for the study of human neuronal development while maintaining the genetic background of the donor patient. Several hIPSC models of NDDs already proved their worth by mimicking several pathological phenotypes found in humans. In this review, we highlight the utility of hIPSCs to pave new paths for NDD research and development of new therapeutic tools, summarize the challenges and advances of hIPSC-culture and neuronal differentiation protocols and discuss the best way to take advantage of these models, illustrating this with examples of success for some NDDs.
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10
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mGluR5 PAMs rescue cortical and behavioural defects in a mouse model of CDKL5 deficiency disorder. Neuropsychopharmacology 2022; 48:877-886. [PMID: 35945276 PMCID: PMC10156697 DOI: 10.1038/s41386-022-01412-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 07/04/2022] [Accepted: 07/19/2022] [Indexed: 12/19/2022]
Abstract
Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a devastating rare neurodevelopmental disease without a cure, caused by mutations of the serine/threonine kinase CDKL5 highly expressed in the forebrain. CDD is characterized by early-onset seizures, severe intellectual disabilities, autistic-like traits, sensorimotor and cortical visual impairments (CVI). The lack of an effective therapeutic strategy for CDD urgently demands the identification of novel druggable targets potentially relevant for CDD pathophysiology. To this aim, we studied Class I metabotropic glutamate receptors 5 (mGluR5) because of their important role in the neuropathological signs produced by the lack of CDKL5 in-vivo, such as defective synaptogenesis, dendritic spines formation/maturation, synaptic transmission and plasticity. Importantly, mGluR5 function strictly depends on the correct expression of the postsynaptic protein Homer1bc that we previously found atypical in the cerebral cortex of Cdkl5-/y mice. In this study, we reveal that CDKL5 loss tampers with (i) the binding strength of Homer1bc-mGluR5 complexes, (ii) the synaptic localization of mGluR5 and (iii) the mGluR5-mediated enhancement of NMDA-induced neuronal responses. Importantly, we showed that the stimulation of mGluR5 activity by administering in mice specific positive-allosteric-modulators (PAMs), i.e., 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) or RO6807794, corrected the synaptic, functional and behavioral defects shown by Cdkl5-/y mice. Notably, in the visual cortex of 2 CDD patients we found changes in synaptic organization that recapitulate those of mutant CDKL5 mice, including the reduced expression of mGluR5, suggesting that these receptors represent a promising therapeutic target for CDD.
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11
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Zhang WJ, Shi LL, Zhang L. Dysregulated cortical synaptic plasticity under methyl-CpG binding protein 2 deficiency and its implication in motor impairments. World J Psychiatry 2022; 12:673-682. [PMID: 35663301 PMCID: PMC9150038 DOI: 10.5498/wjp.v12.i5.673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/16/2021] [Accepted: 04/04/2022] [Indexed: 02/06/2023] Open
Abstract
Caused by the mutation of methyl-CpG binding protein 2 (MeCP2), Rett syndrome leads to a battery of severe neural dysfunctions including the regression of motor coordination and motor learning. Current understanding has revealed the motor cortex as the critical region mediating voluntary movement. In this review article, we will summarize major findings from human patients and animal models regarding the cortical synaptic plasticity under the regulation of MeCP2. We will also discuss how mutation of MeCP2 leads to the disruption of cortical circuitry homeostasis to cause motor deficits. Lastly, potential values of physical exercise and neuromodulation approaches to recover neural plasticity and motor function will be evaluated. All of this evidence may help to accelerate timely diagnosis and effective interventions for Rett syndrome patients.
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Affiliation(s)
- Wei-Jia Zhang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou 510632, Guangdong Province, China
| | - Ling-Ling Shi
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou 510632, Guangdong Province, China
| | - Li Zhang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou 510632, Guangdong Province, China
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12
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Gibel-Russo R, Benacom D, Di Nardo AA. Non-Cell-Autonomous Factors Implicated in Parvalbumin Interneuron Maturation and Critical Periods. Front Neural Circuits 2022; 16:875873. [PMID: 35601531 PMCID: PMC9115720 DOI: 10.3389/fncir.2022.875873] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/04/2022] [Indexed: 02/04/2023] Open
Abstract
From birth to adolescence, the brain adapts to its environmental stimuli through structural and functional remodeling of neural circuits during critical periods of heightened plasticity. They occur across modalities for proper sensory, motor, linguistic, and cognitive development. If they are disrupted by early-life adverse experiences or genetic deficiencies, lasting consequences include behavioral changes, physiological and cognitive deficits, or psychiatric illness. Critical period timing is orchestrated not only by appropriate neural activity but also by a multitude of signals that participate in the maturation of fast-spiking parvalbumin interneurons and the consolidation of neural circuits. In this review, we describe the various signaling factors that initiate critical period onset, such as BDNF, SPARCL1, or OTX2, which originate either from local neurons or glial cells or from extracortical sources such as the choroid plexus. Critical period closure is established by signals that modulate extracellular matrix and myelination, while timing and plasticity can also be influenced by circadian rhythms and by hormones and corticosteroids that affect brain oxidative stress levels or immune response. Molecular outcomes include lasting epigenetic changes which themselves can be considered signals that shape downstream cross-modal critical periods. Comprehensive knowledge of how these signals and signaling factors interplay to influence neural mechanisms will help provide an inclusive perspective on the effects of early adversity and developmental defects that permanently change perception and behavior.
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13
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Gutiérrez JF, Natali G, Giorgi J, De Leonibus E, Tongiorgi E. Mirtazapine treatment in a young female mouse model of Rett syndrome identifies time windows for the rescue of early phenotypes. Exp Neurol 2022; 353:114056. [DOI: 10.1016/j.expneurol.2022.114056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/10/2022] [Accepted: 03/24/2022] [Indexed: 11/26/2022]
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14
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Sánchez-Lafuente CL, Kalynchuk LE, Caruncho HJ, Ausió J. The Role of MeCP2 in Regulating Synaptic Plasticity in the Context of Stress and Depression. Cells 2022; 11:cells11040748. [PMID: 35203405 PMCID: PMC8870391 DOI: 10.3390/cells11040748] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is a transcriptional regulator that is highly abundant in the brain. It binds to methylated genomic DNA to regulate a range of physiological functions implicated in neuronal development and adult synaptic plasticity. MeCP2 has mainly been studied for its role in neurodevelopmental disorders, but alterations in MeCP2 are also present in stress-related disorders such as major depression. Impairments in both stress regulation and synaptic plasticity are associated with depression, but the specific mechanisms underlying these changes have not been identified. Here, we review the interplay between stress, synaptic plasticity, and MeCP2. We focus our attention on the transcriptional regulation of important neuronal plasticity genes such as BDNF and reelin (RELN). Moreover, we provide evidence from recent studies showing a link between chronic stress-induced depressive symptoms and dysregulation of MeCP2 expression, underscoring the role of this protein in stress-related pathology. We conclude that MeCP2 is a promising target for the development of novel, more efficacious therapeutics for the treatment of stress-related disorders such as depression.
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Affiliation(s)
- Carla L. Sánchez-Lafuente
- Division of Medical Sciences, University of Victoria, Victoria, BC V8W 2Y2, Canada; (C.L.S.-L.); (L.E.K.); (H.J.C.)
| | - Lisa E. Kalynchuk
- Division of Medical Sciences, University of Victoria, Victoria, BC V8W 2Y2, Canada; (C.L.S.-L.); (L.E.K.); (H.J.C.)
| | - Hector J. Caruncho
- Division of Medical Sciences, University of Victoria, Victoria, BC V8W 2Y2, Canada; (C.L.S.-L.); (L.E.K.); (H.J.C.)
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
- Correspondence:
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15
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Li W. Excitation and Inhibition Imbalance in Rett Syndrome. Front Neurosci 2022; 16:825063. [PMID: 35250460 PMCID: PMC8894599 DOI: 10.3389/fnins.2022.825063] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/31/2022] [Indexed: 12/12/2022] Open
Abstract
A loss of the excitation/inhibition (E/I) balance in the neural circuit has emerged as a common neuropathological feature in many neurodevelopmental disorders. Rett syndrome (RTT), a prevalent neurodevelopmental disorder that affects 1:10,000-15,000 women globally, is caused by loss-of-function mutations in the Methyl-CpG-binding Protein-2 (Mecp2) gene. E/I imbalance is recognized as the leading cellular and synaptic hallmark that is fundamental to diverse RTT neurological symptoms, including stereotypic hand movements, impaired motor coordination, breathing irregularities, seizures, and learning/memory dysfunctions. E/I balance in RTT is not homogeneously altered but demonstrates brain region and cell type specificity instead. In this review, I elaborate on the current understanding of the loss of E/I balance in a range of brain areas at molecular and cellular levels. I further describe how the underlying cellular mechanisms contribute to the disturbance of the proper E/I ratio. Last, I discuss current pharmacologic innervations for RTT and their role in modifying the E/I balance.
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Affiliation(s)
- Wei Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
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16
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Musi CA, Castaldo AM, Valsecchi AE, Cimini S, Morello N, Pizzo R, Renieri A, Meloni I, Bonati M, Giustetto M, Borsello T. JNK signaling provides a novel therapeutic target for Rett syndrome. BMC Biol 2021; 19:256. [PMID: 34911542 PMCID: PMC8675514 DOI: 10.1186/s12915-021-01190-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 11/11/2021] [Indexed: 11/24/2022] Open
Abstract
Background Rett syndrome (RTT) is a monogenic X-linked neurodevelopmental disorder characterized by loss-of-function mutations in the MECP2 gene, which lead to structural and functional changes in synapse communication, and impairments of neural activity at the basis of cognitive deficits that progress from an early age. While the restoration of MECP2 in animal models has been shown to rescue some RTT symptoms, gene therapy intervention presents potential side effects, and with gene- and RNA-editing approaches still far from clinical application, strategies focusing on signaling pathways downstream of MeCP2 may provide alternatives for the development of more effective therapies in vivo. Here, we investigate the role of the c-Jun N-terminal kinase (JNK) stress pathway in the pathogenesis of RTT using different animal and cell models and evaluate JNK inhibition as a potential therapeutic approach. Results We discovered that the c-Jun N-terminal kinase (JNK) stress pathway is activated in Mecp2-knockout, Mecp2-heterozygous mice, and in human MECP2-mutated iPSC neurons. The specific JNK inhibitor, D-JNKI1, promotes recovery of body weight and locomotor impairments in two mouse models of RTT and rescues their dendritic spine alterations. Mecp2-knockout presents intermittent crises of apnea/hypopnea, one of the most invalidating RTT pathological symptoms, and D-JNKI1 powerfully reduces this breathing dysfunction. Importantly, we discovered that also neurons derived from hiPSC-MECP2 mut show JNK activation, high-phosphorylated c-Jun levels, and cell death, which is not observed in the isogenic control wt allele hiPSCs. Treatment with D-JNKI1 inhibits neuronal death induced by MECP2 mutation in hiPSCs mut neurons. Conclusions As a summary, we found altered JNK signaling in models of RTT and suggest that D-JNKI1 treatment prevents clinical symptoms, with coherent results at the cellular, molecular, and functional levels. This is the first proof of concept that JNK plays a key role in RTT and its specific inhibition offers a new and potential therapeutic tool to tackle RTT. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01190-2.
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Affiliation(s)
- Clara Alice Musi
- Department of Pharmacological and Biomolecular Sciences, Milan University, Via Balzaretti 9, 20133, Milan, Italy.,Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri-IRCCS, Via Mario Negri 2, 20156, Milan, Italy
| | - Anna Maria Castaldo
- Department of Pharmacological and Biomolecular Sciences, Milan University, Via Balzaretti 9, 20133, Milan, Italy
| | | | - Sara Cimini
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri-IRCCS, Via Mario Negri 2, 20156, Milan, Italy
| | - Noemi Morello
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Riccardo Pizzo
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | | | | | - Maurizio Bonati
- Department of Public Heath, Istituto di Ricerche Farmacologiche Mario Negri-IRCCS, Milan, Italy
| | - Maurizio Giustetto
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Tiziana Borsello
- Department of Pharmacological and Biomolecular Sciences, Milan University, Via Balzaretti 9, 20133, Milan, Italy. .,Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri-IRCCS, Via Mario Negri 2, 20156, Milan, Italy.
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17
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Ciptasari U, van Bokhoven H. The phenomenal epigenome in neurodevelopmental disorders. Hum Mol Genet 2021; 29:R42-R50. [PMID: 32766754 PMCID: PMC7530535 DOI: 10.1093/hmg/ddaa175] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/16/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022] Open
Abstract
Disruption of chromatin structure due to epimutations is a leading genetic etiology of neurodevelopmental disorders, collectively known as chromatinopathies. We show that there is an increasing level of convergence from the high diversity of genes that are affected by mutations to the molecular networks and pathways involving the respective proteins, the disrupted cellular and subcellular processes, and their consequence for higher order cellular network function. This convergence is ultimately reflected by specific phenotypic features shared across the various chromatinopathies. Based on these observations, we propose that the commonly disrupted molecular and cellular anomalies might provide a rational target for the development of symptomatic interventions for defined groups of genetically distinct neurodevelopmental disorders.
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Affiliation(s)
- Ummi Ciptasari
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud university medical center, 6500 HB Nijmegen, The Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud university medical center, 6500 HB Nijmegen, The Netherlands.,Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud university medical center, 6500 HB Nijmegen, The Netherlands
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18
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Longo F, Klann E. Reciprocal control of translation and transcription in autism spectrum disorder. EMBO Rep 2021; 22:e52110. [PMID: 33977633 DOI: 10.15252/embr.202052110] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/20/2021] [Accepted: 04/19/2021] [Indexed: 12/11/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted patterns of interest and repetitive behaviors. ASD is genetically heterogeneous and is believed to be caused by both inheritable and de novo gene variations. Studies have revealed an extremely complex genetic landscape of ASD, favoring the idea that mutations in different clusters of genes interfere with interconnected downstream signaling pathways and circuitry, resulting in aberrant behavior. In this review, we describe a select group of candidate genes that represent both syndromic and non-syndromic forms of ASD and encode proteins that are important in transcriptional and translational regulation. We focus on the interplay between dysregulated translation and transcription in ASD with the hypothesis that dysregulation of each synthetic process triggers a feedback loop to act on the other, which ultimately exacerbates ASD pathophysiology. Finally, we summarize findings from interdisciplinary studies that pave the way for the investigation of the cooperative impact of different genes and pathways underlying the development of ASD.
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Affiliation(s)
- Francesco Longo
- Center for Neural Science, New York University, New York, NY, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA
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19
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Patrizi A, Awad PN, Chattopadhyaya B, Li C, Di Cristo G, Fagiolini M. Accelerated Hyper-Maturation of Parvalbumin Circuits in the Absence of MeCP2. Cereb Cortex 2021; 30:256-268. [PMID: 31038696 DOI: 10.1093/cercor/bhz085] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 02/21/2019] [Accepted: 03/29/2019] [Indexed: 12/27/2022] Open
Abstract
Methyl-CpG-binding protein 2 (MeCP2) mutations are the primary cause of Rett syndrome, a severe neurodevelopmental disorder. Cortical parvalbumin GABAergic interneurons (PV) make exuberant somatic connections onto pyramidal cells in the visual cortex of Mecp2-deficient mice, which contributes to silencing neuronal cortical circuits. This phenotype can be rescued independently of Mecp2 by environmental, pharmacological, and genetic manipulation. It remains unknown how Mecp2 mutation can result in abnormal inhibitory circuit refinement. In the present manuscript, we examined the development of GABAergic circuits in the primary visual cortex of Mecp2-deficient mice. We identified that PV circuits were the only GABAergic interneurons to be upregulated, while other interneurons were downregulated. Acceleration of PV cell maturation was accompanied by increased PV cells engulfment by perineuronal nets (PNNs) and by an increase of PV cellular and PNN structural complexity. Interestingly, selective deletion of Mecp2 from PV cells was sufficient to drive increased structure complexity of PNN. Moreover, the accelerated PV and PNN maturation was recapitulated in organotypic cultures. Our results identify a specific timeline of disruption of GABAergic circuits in the absence of Mecp2, indicating a possible cell-autonomous role of MeCP2 in the formation of PV cellular arbors and PNN structures in the visual cortex.
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Affiliation(s)
- Annarita Patrizi
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Schaller Research Group Leader at the German Cancer Research Center (DKFZ), Heildeberg, Germany
| | - Patricia N Awad
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Chloe Li
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Graziella Di Cristo
- Department of Neurosciences, Université de Montréal, Montreal, Canada.,CHU Ste Justine Research Center, Montreal, QC Canada
| | - Michela Fagiolini
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,International Research Center for Neurointelligence, University of Tokyo Institutes for Advanced Study, Tokyo, Japan
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20
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Adcock KS, Blount AE, Morrison RA, Alvarez-Dieppa A, Kilgard MP, Engineer CT, Hays SA. Deficits in skilled motor and auditory learning in a rat model of Rett syndrome. J Neurodev Disord 2020; 12:27. [PMID: 32988374 PMCID: PMC7523346 DOI: 10.1186/s11689-020-09330-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/18/2020] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Rett syndrome is an X-linked neurodevelopmental disorder caused by a mutation in the gene MECP2. Individuals with Rett syndrome display developmental regression at an early age, and develop a range of motor, auditory, cognitive, and social impairments. Several studies have successfully modeled some aspects of dysfunction and Rett syndrome-like phenotypes in transgenic mouse and rat models bearing mutations in the MECP2 gene. Here, we sought to extend these findings and characterize skilled learning, a more complex behavior known to be altered in Rett syndrome. METHODS We evaluated the acquisition and performance of auditory and motor function on two complex tasks in heterozygous female Mecp2 rats. Animals were trained to perform a speech discrimination task or a skilled forelimb reaching task. RESULTS Our results reveal that Mecp2 rats display slower acquisition and reduced performance on an auditory discrimination task than wild-type (WT) littermates. Similarly, Mecp2 rats exhibit impaired learning rates and worse performance on a skilled forelimb motor task compared to WT. CONCLUSIONS Together, these findings illustrate novel deficits in skilled learning consistent with clinical manifestation of Rett syndrome and provide a framework for development of therapeutic strategies to improve these complex behaviors.
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Affiliation(s)
- Katherine S Adcock
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.
| | - Abigail E Blount
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Robert A Morrison
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Amanda Alvarez-Dieppa
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Michael P Kilgard
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Crystal T Engineer
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Seth A Hays
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
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21
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Flores Gutiérrez J, De Felice C, Natali G, Leoncini S, Signorini C, Hayek J, Tongiorgi E. Protective role of mirtazapine in adult female Mecp2 +/- mice and patients with Rett syndrome. J Neurodev Disord 2020; 12:26. [PMID: 32988385 PMCID: PMC7523042 DOI: 10.1186/s11689-020-09328-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/27/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Rett syndrome (RTT), an X-linked neurodevelopmental rare disease mainly caused by MECP2-gene mutations, is a prototypic intellectual disability disorder. Reversibility of RTT-like phenotypes in an adult mouse model lacking the Mecp2-gene has given hope of treating the disease at any age. However, adult RTT patients still urge for new treatments. Given the relationship between RTT and monoamine deficiency, we investigated mirtazapine (MTZ), a noradrenergic and specific-serotonergic antidepressant, as a potential treatment. METHODS Adult heterozygous-Mecp2 (HET) female mice (6-months old) were treated for 30 days with 10 mg/kg MTZ and assessed for general health, motor skills, motor learning, and anxiety. Motor cortex, somatosensory cortex, and amygdala were analyzed for parvalbumin expression. Eighty RTT adult female patients harboring a pathogenic MECP2 mutation were randomly assigned to treatment to MTZ for insomnia and mood disorders (mean age = 23.1 ± 7.5 years, range = 16-47 years; mean MTZ-treatment duration = 1.64 ± 1.0 years, range = 0.08-5.0 years). Rett clinical severity scale (RCSS) and motor behavior assessment scale (MBAS) were retrospectively analyzed. RESULTS In HET mice, MTZ preserved motor learning from deterioration and normalized parvalbumin levels in the primary motor cortex. Moreover, MTZ rescued the aberrant open-arm preference behavior observed in HET mice in the elevated plus-maze (EPM) and normalized parvalbumin expression in the barrel cortex. Since whisker clipping also abolished the EPM-related phenotype, we propose it is due to sensory hypersensitivity. In patients, MTZ slowed disease progression or induced significant improvements for 10/16 MBAS-items of the M1 social behavior area: 4/7 items of the M2 oro-facial/respiratory area and 8/14 items of the M3 motor/physical signs area. CONCLUSIONS This study provides the first evidence that long-term treatment of adult female heterozygous Mecp2tm1.1Bird mice and adult Rett patients with the antidepressant mirtazapine is well tolerated and that it protects from disease progression and improves motor, sensory, and behavioral symptoms.
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Affiliation(s)
- Javier Flores Gutiérrez
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri, 5 - 34127, Trieste, Italy
| | - Claudio De Felice
- Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy
| | - Giulia Natali
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri, 5 - 34127, Trieste, Italy
| | - Silvia Leoncini
- Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy.,Child Neuropsychiatry Unit, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy
| | - Cinzia Signorini
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - Joussef Hayek
- Child Neuropsychiatry Unit, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy.,Pediatric Speciality Center "L'Isola di Bau", 50052 Certaldo, Florence, Italy
| | - Enrico Tongiorgi
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri, 5 - 34127, Trieste, Italy.
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22
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Lateralized Expression of Cortical Perineuronal Nets during Maternal Experience is Dependent on MECP2. eNeuro 2020; 7:ENEURO.0500-19.2020. [PMID: 32332080 PMCID: PMC7294466 DOI: 10.1523/eneuro.0500-19.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 02/06/2023] Open
Abstract
Cortical neuronal circuits along the sensorimotor pathways are shaped by experience during critical periods of heightened plasticity in early postnatal development. After closure of critical periods, measured histologically by the formation and maintenance of extracellular matrix structures called perineuronal nets (PNNs), the adult mouse brain exhibits restricted plasticity and maturity. Mature PNNs are typically considered to be stable structures that restrict synaptic plasticity on cortical parvalbumin+ (PV+) GABAergic neurons. Changes in environment (i.e., novel behavioral training) or social contexts (i.e., motherhood) are known to elicit synaptic plasticity in relevant neural circuitry. However, little is known about concomitant changes in the PNNs surrounding the cortical PV+ GABAergic neurons. Here, we show novel changes in PNN density in the primary somatosensory cortex (SS1) of adult female mice after maternal experience [called surrogate (Sur)], using systematic microscopy analysis of a whole brain region. On average, PNNs were increased in the right barrel field and decreased in the left forelimb regions. Individual mice had left hemisphere dominance in PNN density. Using adult female mice deficient in methyl-CpG-binding protein 2 (MECP2), an epigenetic regulator involved in regulating experience-dependent plasticity, we found that MECP2 is critical for this precise and dynamic expression of PNN. Adult naive Mecp2-heterozygous (Het) females had increased PNN density in specific subregions in both hemispheres before maternal experience, compared with wild-type (WT) littermate controls. The laterality in PNN expression seen in naive Het (NH) was lost after maternal experience in Sur Het (SH) mice, suggesting possible intact mechanisms for plasticity. Together, our results identify subregion and hemisphere-specific alterations in PNN expression in adult females, suggesting extracellular matrix plasticity as a possible neurobiological mechanism for adult behaviors in rodents.
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23
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Fagiolini M, Patrizi A, LeBlanc J, Jin LW, Maezawa I, Sinnett S, Gray SJ, Molholm S, Foxe JJ, Johnston MV, Naidu S, Blue M, Hossain A, Kadam S, Zhao X, Chang Q, Zhou Z, Zoghbi H. Intellectual and Developmental Disabilities Research Centers: A Multidisciplinary Approach to Understand the Pathogenesis of Methyl-CpG Binding Protein 2-related Disorders. Neuroscience 2020; 445:190-206. [PMID: 32360592 DOI: 10.1016/j.neuroscience.2020.04.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/20/2022]
Abstract
Disruptions in the gene encoding methyl-CpG binding protein 2 (MECP2) underlie complex neurodevelopmental disorders including Rett Syndrome (RTT), MECP2 duplication disorder, intellectual disabilities, and autism. Significant progress has been made on the molecular and cellular basis of MECP2-related disorders providing a new framework for understanding how altered epigenetic landscape can derail the formation and refinement of neuronal circuits in early postnatal life and proper neurological function. This review will summarize selected major findings from the past years and particularly highlight the integrated and multidisciplinary work done at eight NIH-funded Intellectual and Developmental Disabilities Research Centers (IDDRC) across the US. Finally, we will outline a path forward with identification of reliable biomarkers and outcome measures, longitudinal preclinical and clinical studies, reproducibility of results across centers as a synergistic effort to decode and treat the pathogenesis of the complex MeCP2 disorders.
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Affiliation(s)
- Michela Fagiolini
- Children's Hospital Intellectual and Developmental Disabilities Research Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Annarita Patrizi
- Children's Hospital Intellectual and Developmental Disabilities Research Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jocelyn LeBlanc
- Children's Hospital Intellectual and Developmental Disabilities Research Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Lee-Way Jin
- UC Davis MIND Institute, University of California, Sacramento, CA, USA
| | - Izumi Maezawa
- UC Davis MIND Institute, University of California, Sacramento, CA, USA
| | - Sarah Sinnett
- UNC Intellectual and Developmental Disabilities Research Center, University of North Carolina, Gene Therapy Center and Dept. of Ophthalmology, Chapel Hill, NC, USA; Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Steven J Gray
- UNC Intellectual and Developmental Disabilities Research Center, University of North Carolina, Gene Therapy Center and Dept. of Ophthalmology, Chapel Hill, NC, USA; Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sophie Molholm
- The Cognitive Neurophysiology Laboratory, Departments of Pediatrics, Neuroscience, and Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - John J Foxe
- The Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Michael V Johnston
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Sakkubai Naidu
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Mary Blue
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Ahamed Hossain
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Shilpa Kadam
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Quiang Chang
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Zhaolan Zhou
- Department of Genetic, Epigenetic Institute, University of Pennsylvania Perelman School of Medicine, Intellectual and Developmental Disabilities Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Huda Zoghbi
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, USA
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Bernardo P, Cobb S, Coppola A, Tomasevic L, Di Lazzaro V, Bravaccio C, Manganelli F, Dubbioso R. Neurophysiological Signatures of Motor Impairment in Patients with Rett Syndrome. Ann Neurol 2020; 87:763-773. [PMID: 32129908 DOI: 10.1002/ana.25712] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 03/02/2020] [Accepted: 03/02/2020] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Rett syndrome (RTT) is an X-linked dominant neurodevelopmental disorder due to pathogenic mutations in the MECP2 gene. Motor impairment constitutes the core diagnostic feature of RTT. Preclinical studies have consistently demonstrated alteration of excitation/inhibition (E/I) balance and aberrant synaptic plasticity at the cortical level. We aimed to understand neurobiological mechanisms underlying motor deficit by assessing in vivo synaptic plasticity and E/I balance in the primary motor cortex (M1). METHODS In 14 patients with typical RTT, 9 epilepsy control patients, and 11 healthy controls, we applied paired-pulse transcranial magnetic stimulation (TMS) protocols to evaluate the excitation index, a biomarker reflecting the contribution of inhibitory and facilitatory circuits in M1. Intermittent TMS-theta burst stimulation was used to probe long-term potentiation (LTP)-like plasticity in M1. Motor impairment, assessed by ad hoc clinical scales, was correlated with neurophysiological metrics. RESULTS RTT patients displayed a significant increase of the excitation index (p = 0.003), as demonstrated by the reduction of short-interval intracortical inhibition and increase of intracortical facilitation, suggesting a shift toward cortical excitation likely due to GABAergic dysfunction. Impairment of inhibitory circuits was also confirmed by the reduction of long-interval intracortical inhibition (p = 0.002). LTP-like plasticity in M1 was abolished (p = 0.008) and scaled with motor disability (all p = 0.003). INTERPRETATION TMS is a method that can be used to assess cortical motor function in RTT patients. Our findings support the introduction of TMS measures in clinical and research settings to monitor the progression of motor deficit and response to treatment. ANN NEUROL 2020;87:763-773.
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Affiliation(s)
- Pia Bernardo
- Department of Neuroscience, Child Neuropsychiatry Unit, Santobono-Pausilipon Children's Hospital, Naples, Italy.,Department of Translational Medical Sciences, Child Neuropsychiatry Unit, University of Naples Federico II, Naples, Italy
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Antonietta Coppola
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples Federico II, Naples, Italy
| | - Leo Tomasevic
- Danish Research Center for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Campus Bio-Medico University of Rome, Rome, Italy
| | - Carmela Bravaccio
- Department of Translational Medical Sciences, Child Neuropsychiatry Unit, University of Naples Federico II, Naples, Italy
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples Federico II, Naples, Italy
| | - Raffaele Dubbioso
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples Federico II, Naples, Italy
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25
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Altered excitatory transmission onto hippocampal interneurons in the IQSEC2 mouse model of X-linked neurodevelopmental disease. Neurobiol Dis 2020; 137:104758. [PMID: 31978606 DOI: 10.1016/j.nbd.2020.104758] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 12/16/2019] [Accepted: 01/20/2020] [Indexed: 02/01/2023] Open
Abstract
Mutations in the X-linked gene IQSEC2 are associated with multiple cases of epilepsy, epileptic encephalopathy, intellectual disability and autism spectrum disorder, the mechanistic understanding and successful treatment of which remain a significant challenge in IQSEC2 and related neurodevelopmental genetic diseases. To investigate disease etiology, we studied behaviors and synaptic function in IQSEC2 deficient mice. Hemizygous Iqsec2 null males exhibit growth deficits, hyperambulation and hyperanxiety phenotypes. Adult hemizygotes experience lethal spontaneous seizures, but paradoxically have a significantly increased threshold to electrically induced limbic seizures and relative resistance to chemically induced seizures. Although there are no gross defects in brain morphology, hemizygotes exhibit stark hippocampal reactive astrogliosis. Electrophysiological recordings of hippocampal neurons reveal increased excitatory drive specifically onto interneurons, and significant alterations in intrinsic electrical properties specific to the interneuron population. As they age, hemizygotes also develop an increased abundance of parvalbumin-positive interneurons in the hippocampus, neurons in which IQSEC2 is expressed in addition to the excitatory neurons. These findings point to a novel role of IQSEC2 in hippocampal interneuron synaptic function and development with implications for a class of intractable neurodevelopmental diseases.
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26
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Maternal Experience-Dependent Cortical Plasticity in Mice Is Circuit- and Stimulus-Specific and Requires MECP2. J Neurosci 2020; 40:1514-1526. [PMID: 31911459 DOI: 10.1523/jneurosci.1964-19.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/12/2019] [Accepted: 12/20/2019] [Indexed: 01/26/2023] Open
Abstract
The neurodevelopmental disorder Rett syndrome is caused by mutations in the gene Mecp2 Misexpression of the protein MECP2 is thought to contribute to neuropathology by causing dysregulation of plasticity. Female heterozygous Mecp2 mutants (Mecp2het ) failed to acquire a learned maternal retrieval behavior when exposed to pups, an effect linked to disruption of parvalbumin-expressing inhibitory interneurons (PV) in the auditory cortex. Nevertheless, how dysregulated PV networks affect the neural activity dynamics that underlie auditory cortical plasticity during early maternal experience is unknown. Here we show that maternal experience in WT adult female mice (WT) triggers suppression of PV auditory responses. We also observe concomitant disinhibition of auditory responses in deep-layer pyramidal neurons that is selective for behaviorally relevant pup vocalizations. These neurons further exhibit sharpened tuning for pup vocalizations following maternal experience. All of these neuronal changes are abolished in Mecp2het , suggesting that they are an essential component of maternal learning. This is further supported by our finding that genetic manipulation of GABAergic networks that restores accurate retrieval behavior in Mecp2het also restores maternal experience-dependent plasticity of PV. Our data are consistent with a growing body of evidence that cortical networks are particularly vulnerable to mutations of Mecp2 in PV neurons. Moreover, our work links, for the first time, impaired in vivo cortical plasticity in awake Mecp2 mutant animals to a natural, ethologically relevant behavior.SIGNIFICANCE STATEMENT Rett syndrome is a genetic disorder that includes language communication problems. Nearly all Rett syndrome is caused by mutations in the gene that produces the protein MECP2, which is important for changes in brain connectivity believed to underlie learning. We previously showed that female Mecp2 mutants fail to learn a simple maternal care behavior performed in response to their pups' distress cries. This impairment appeared to critically involve inhibitory neurons in the auditory cortex called parvalbumin neurons. Here we record from these neurons before and after maternal experience, and we show that they adapt their response to pup calls during maternal learning in nonmutants, but not in mutants. This adaptation is partially restored by a manipulation that improves learning.
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Interneuron deficits in neurodevelopmental disorders: Implications for disease pathology and interneuron-based therapies. Eur J Paediatr Neurol 2020; 24:81-88. [PMID: 31870698 PMCID: PMC7152321 DOI: 10.1016/j.ejpn.2019.12.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 12/06/2019] [Indexed: 12/16/2022]
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Kadam SD, Sullivan BJ, Goyal A, Blue ME, Smith-Hicks C. Rett Syndrome and CDKL5 Deficiency Disorder: From Bench to Clinic. Int J Mol Sci 2019; 20:ijms20205098. [PMID: 31618813 PMCID: PMC6834180 DOI: 10.3390/ijms20205098] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/08/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Rett syndrome (RTT) and CDKL5 deficiency disorder (CDD) are two rare X-linked developmental brain disorders with overlapping but distinct phenotypic features. This review examines the impact of loss of methyl-CpG-binding protein 2 (MeCP2) and cyclin-dependent kinase-like 5 (CDKL5) on clinical phenotype, deficits in synaptic- and circuit-homeostatic mechanisms, seizures, and sleep. In particular, we compare the overlapping and contrasting features between RTT and CDD in clinic and in preclinical studies. Finally, we discuss lessons learned from recent clinical trials while reviewing the findings from pre-clinical studies.
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Affiliation(s)
- Shilpa D Kadam
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Brennan J Sullivan
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Archita Goyal
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Mary E Blue
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Constance Smith-Hicks
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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29
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Pizzo R, Lamarca A, Sassoè-Pognetto M, Giustetto M. Structural Bases of Atypical Whisker Responses in a Mouse Model of CDKL5 Deficiency Disorder. Neuroscience 2019; 445:130-143. [PMID: 31472213 DOI: 10.1016/j.neuroscience.2019.08.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/13/2019] [Accepted: 08/20/2019] [Indexed: 02/06/2023]
Abstract
Mutations in the CDKL5 (cyclin-dependent kinase-like 5) gene cause CDKL5 Deficiency Disorder (CDD), a severe neurodevelopmental syndrome where patients exhibit early-onset seizures, intellectual disability, stereotypies, limited or absent speech, autism-like symptoms and sensory impairments. Mounting evidences indicate that disrupted sensory perception and processing represent core signs also in mouse models of CDD; however we have very limited knowledge on their underlying causes. In this study, we investigated how CDKL5 deficiency affects synaptic organization and experience-dependent plasticity in the thalamo-cortical (TC) pathway carrying whisker-related tactile information to the barrel cortex (BC). By using synapse-specific antibodies and confocal microscopy, we found that Cdkl5-KO mice display a lower density of TC synapses in the BC that was paralleled by a reduction of cortico-cortical (CC) connections compared to wild-type mice. These synaptic defects were accompanied by reduced BC activation, as shown by a robust decrease of c-fos immunostaining, and atypical behavioral responses to whisker-mediated tactile stimulation. Notably, a 2-day paradigm of enriched whisker stimulation rescued both number and configuration of excitatory synapses in Cdkl5-KO mice, restored cortical activity and normalized behavioral responses to wild-type mice levels. Our findings disclose a novel and unsuspected role of CDKL5 in controlling the organization and experience-induced modifications of excitatory connections in the BC and indicate how mutations of CDKL5 produce failures in higher-order processing of somatosensory stimuli. This article is part of a Special Issue entitled: Animal Models of Neurodevelopmental Disorders.
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Affiliation(s)
- R Pizzo
- Department of Neuroscience, University of Turin, Corso Massimo D'Azeglio 52, 10126 Turin, Italy
| | - A Lamarca
- Department of Neuroscience, University of Turin, Corso Massimo D'Azeglio 52, 10126 Turin, Italy
| | - M Sassoè-Pognetto
- Department of Neuroscience, University of Turin, Corso Massimo D'Azeglio 52, 10126 Turin, Italy; National Institute of Neuroscience-Italy, Corso Massimo D'Azeglio 52, 10126 Turin, Italy
| | - M Giustetto
- Department of Neuroscience, University of Turin, Corso Massimo D'Azeglio 52, 10126 Turin, Italy; National Institute of Neuroscience-Italy, Corso Massimo D'Azeglio 52, 10126 Turin, Italy.
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30
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Asgarihafshejani A, Nashmi R, Delaney KR. Cell-Genotype Specific Effects of Mecp2 Mutation on Spontaneous and Nicotinic Acetylcholine Receptor-Evoked Currents in Medial Prefrontal Cortical Pyramidal Neurons in Female Rett Model Mice. Neuroscience 2019; 414:141-153. [PMID: 31299345 DOI: 10.1016/j.neuroscience.2019.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 02/08/2023]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutation in the X-linked MECP2 gene. Random X-inactivation produces a mosaic of mutant (MT) and wild-type (WT) neurons in female Mecp2+/- (het) mice. Many RTT symptoms are alleviated by increasing activity in medial prefrontal cortex (mPFC) in RTT model mice (Howell et al., 2017). Using a GFP-MeCP2 fusion protein to distinguish WT from MT pyramidal neurons in mPFC we found cell autonomous (cell genotype specific) and non-autonomous effects of MeCP2 deficiency on spontaneous excitatory/inhibitory balance, nicotinic acetylcholine receptor (nAChR) currents and evoked activity. MT Layer 5 and 6 (L5, L6) neurons of male nulls, and MT L6 of het mice had reduced spontaneous excitatory synaptic input compared to WT in wild-type male (WTm), female (WTf) and het mice. Inhibitory synaptic charge in MT L6 equaled WT in 2-4-month hets. At 6-7 months inhibitory charge in WT in het slices was increased compared to both MT in het and WT in WTf; however, in hets the excitatory/inhibitory charge ratio was still greater in WT compared to MT. nAChR currents were reduced in L6 of nulls and MT L6 in het slices compared to WT neurons of het, WTm and WTf. At 2-4 months, ACh perfusion increased frequency of inhibitory currents to L6 neurons equally in all genotypes but increased excitatory inputs to MT and WT in hets less than WT in WTfs. Unexpectedly ACh perfusion evoked greater sustained IPSC and EPSC input to L5 neurons of nulls compared to WTm.
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Affiliation(s)
| | - Raad Nashmi
- Dept. of Biology, University of Victoria, Victoria, BC, Canada V8W2Y2
| | - Kerry R Delaney
- Dept. of Biology, University of Victoria, Victoria, BC, Canada V8W2Y2.
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Phillips ML, Robinson HA, Pozzo-Miller L. Ventral hippocampal projections to the medial prefrontal cortex regulate social memory. eLife 2019; 8:e44182. [PMID: 31112129 PMCID: PMC6542587 DOI: 10.7554/elife.44182] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 05/17/2019] [Indexed: 12/13/2022] Open
Abstract
Inputs from the ventral hippocampus (vHIP) to the medial prefrontal cortex (mPFC) are implicated in several neuropsychiatric disorders. Here, we show that the vHIP-mPFC projection is hyperactive in the Mecp2 knockout mouse model of the autism spectrum disorder Rett syndrome, which has deficits in social memory. Long-term excitation of mPFC-projecting vHIP neurons in wild-type mice impaired social memory, whereas their long-term inhibition in Rett mice rescued social memory deficits. The extent of social memory improvement was negatively correlated with vHIP-evoked responses in mPFC slices, on a mouse-per-mouse basis. Acute manipulations of the vHIP-mPFC projection affected social memory in a region and behavior selective manner, suggesting that proper vHIP-mPFC signaling is necessary to recall social memories. In addition, we identified an altered pattern of vHIP innervation of mPFC neurons, and increased synaptic strength of vHIP inputs onto layer five pyramidal neurons as contributing factors of aberrant vHIP-mPFC signaling in Rett mice.
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Affiliation(s)
- Mary L Phillips
- Department of NeurobiologyThe University of Alabama at BirminghamBirminghamUnited States
| | - Holly Anne Robinson
- Department of NeurobiologyThe University of Alabama at BirminghamBirminghamUnited States
| | - Lucas Pozzo-Miller
- Department of NeurobiologyThe University of Alabama at BirminghamBirminghamUnited States
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32
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Structural maturation of cortical perineuronal nets and their perforating synapses revealed by superresolution imaging. Proc Natl Acad Sci U S A 2019; 116:7071-7076. [PMID: 30890637 DOI: 10.1073/pnas.1817222116] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Parvalbumin-positive (PV+) interneurons play a pivotal role in orchestrating windows of experience-dependent brain plasticity during development. Critical period closure is marked by the condensation of a perineuronal net (PNN) tightly enwrapping subsets of PV+ neurons, both acting as a molecular brake on plasticity and maintaining mature PV+ cell signaling. As much of the molecular organization of PNNs exists at length scales near or below the diffraction limit of light microscopy, we developed a superresolution imaging and analysis platform to visualize the structural organization of PNNs and the synaptic inputs perforating them in primary visual cortex. We identified a structural trajectory of PNN maturation featuring a range of net structures, which was accompanied by an increase in Synaptotagmin-2 (Syt2) signals on PV+ cells suggestive of increased inhibitory input between PV+ neurons. The same structural trajectory was followed by PNNs both during normal development and under conditions of critical period delay by total sensory deprivation or critical period acceleration by deletion of MeCP2, the causative gene for Rett syndrome, despite shifted maturation levels under these perturbations. Notably, superresolution imaging further revealed a decrease in Syt2 signals alongside an increase in vesicular glutamate transporter-2 signals on PV+ cells in MeCP2-deficient animals, suggesting weaker recurrent inhibitory input between PV+ neurons and stronger thalamocortical excitatory inputs onto PV+ cells. These results imply a latent imbalanced circuit signature that might promote cortical silencing in Rett syndrome before the functional regression of vision.
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