51
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van Liempd SM, Cabrera D, Lee FY, González E, Dell'Angelica EC, Ghiani CA, Falcon-Perez JM. BLOC-1 deficiency causes alterations in amino acid profile and in phospholipid and adenosine metabolism in the postnatal mouse hippocampus. Sci Rep 2017; 7:5231. [PMID: 28701731 PMCID: PMC5507893 DOI: 10.1038/s41598-017-05465-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 05/31/2017] [Indexed: 01/20/2023] Open
Abstract
Biogenesis of lysosome-related organelles complex-1 (BLOC-1) is a protein complex involved in the formation of endosomal tubular structures that mediates the sorting of protein cargoes to specialised compartments. In this study, we present insights into the metabolic consequences caused by BLOC-1 deficiency in pallid mice, which carry a null mutation in the Bloc1s6 gene encoding an essential component of this complex. The metabolome of the hippocampus of pallid mice was analysed using an untargeted, liquid chromatography-coupled mass spectrometric approach. After data pre-treatment, statistical analysis and pathway enrichment, we have identified 28 metabolites that showed statistically significant changes between pallid and wild-type control. These metabolites included amino acids, nucleobase-containing compounds and lysophospholipids. Interestingly, pallid mice displayed increased hippocampal levels of the neurotransmitters glutamate and N-acetyl-aspartyl-glutamic acid (NAAG) and their precursor glutamine. Expression of the sodium-coupled neutral amino acid transporter 1 (SNAT1), which transports glutamine into neurons, was also upregulated. Conversely, levels of the neurotransmitter precursors phenylalanine and tryptophan were decreased. Interestingly, many of these changes could be mapped to overlapping metabolic pathways. The observed metabolic alterations are likely to affect neurotransmission and neuronal homeostasis and in turn could mediate the memory and behavioural impairments observed in BLOC-1-deficient mice.
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Affiliation(s)
- S M van Liempd
- Metabolomics Platform. CIC bioGUNE, CIBER, Derio, 48260, Spain.
| | - D Cabrera
- Metabolomics Platform. CIC bioGUNE, CIBER, Derio, 48260, Spain
| | - F Y Lee
- Departments of Pathology & Laboratory Medicine and Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - E González
- Metabolomics Platform. CIC bioGUNE, CIBER, Derio, 48260, Spain
| | - E C Dell'Angelica
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - C A Ghiani
- Departments of Pathology & Laboratory Medicine and Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - J M Falcon-Perez
- Metabolomics Platform. CIC bioGUNE, CIBER, Derio, 48260, Spain. .,IKERBASQUE Research Foundation, Bilbao, Spain.
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52
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Martin E, El-Behi M, Fontaine B, Delarasse C. Analysis of Microglia and Monocyte-derived Macrophages from the Central Nervous System by Flow Cytometry. J Vis Exp 2017. [PMID: 28671658 DOI: 10.3791/55781] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Numerous studies have demonstrated the role of immune cells, in particular macrophages, in central nervous system (CNS) pathologies. There are two main macrophage populations in the CNS: (i) the microglia, which are the resident macrophages of the CNS and are derived from yolk sac progenitors during embryogenesis, and (ii) the monocyte-derived macrophages (MDM), which can infiltrate the CNS during disease and are derived from bone marrow progenitors. The roles of each macrophage subpopulation differ depending on the pathology being studied. Furthermore, there is no consensus on the histological markers or the distinguishing criteria used for these macrophage subpopulations. However, the analysis of the expression profiles of the CD11b and CD45 markers by flow cytometry allows us to distinguish the microglia (CD11b+CD45med) from the MDM (CD11b+CD45high). In this protocol, we show that the density gradient centrifugation and the flow cytometry analysis can be used to characterize these CNS macrophage subpopulations, and to study several markers of interest expressed by these cells as we recently published. Thus, this technique can further our understanding of the role of macrophages in mouse models of neurological diseases and can also be used to evaluate drug effects on these cells.
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Affiliation(s)
- Elodie Martin
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM
| | - Mohamed El-Behi
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM
| | - Bertrand Fontaine
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM; AP-HP, Hôpital de la Pitié Salpêtrière
| | - Cecile Delarasse
- Inserm U 1227, CNRS UMR 7225; Sorbonne Universités, UPMC, University of Paris; Institut du Cerveau et de la Moelle épinière, ICM;
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53
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Vilhardt F, Haslund‐Vinding J, Jaquet V, McBean G. Microglia antioxidant systems and redox signalling. Br J Pharmacol 2017; 174:1719-1732. [PMID: 26754582 PMCID: PMC5446583 DOI: 10.1111/bph.13426] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 12/15/2015] [Accepted: 01/07/2016] [Indexed: 12/13/2022] Open
Abstract
For many years, microglia, the resident CNS macrophages, have been considered only in the context of pathology, but microglia are also glial cells with important physiological functions. Microglia-derived oxidant production by NADPH oxidase (NOX2) is implicated in many CNS disorders. Oxidants do not stand alone, however, and are not always pernicious. We discuss in general terms, and where available in microglia, GSH synthesis and relation to cystine import and glutamate export, and the thioredoxin system as the most important antioxidative defence mechanism, and further, we discuss in the context of protein thiolation of target redox proteins the necessity for tightly localized, timed and confined oxidant production to work in concert with antioxidant proteins to promote redox signalling. NOX2-mediated redox signalling modulates the acquisition of the classical or alternative microglia activation phenotypes by regulating major transcriptional programs mediated through NF-κB and Nrf2, major regulators of the inflammatory and antioxidant response respectively. As both antioxidants and NOX-derived oxidants are co-secreted, in some instances redox signalling may extend to neighboring cells through modification of surface or cytosolic target proteins. We consider a role for microglia NOX-derived oxidants in paracrine modification of synaptic function through long term depression and in the communication with the adaptive immune system. There is little doubt that a continued foray into the functions of the antioxidant response in microglia will reveal antioxidant proteins as dynamic players in redox signalling, which in concert with NOX-derived oxidants fulfil important roles in the autocrine or paracrine regulation of essential enzymes or transcriptional programs. LINKED ARTICLES This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.
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Affiliation(s)
| | - J Haslund‐Vinding
- Institute of Cellular and Molecular MedicineCopenhagen UniversityCopenhagenDenmark
- Department of Pathology and ImmunologyCentre Médical UniversitaireGenevaSwitzerland
| | - V Jaquet
- Department of Pathology and ImmunologyCentre Médical UniversitaireGenevaSwitzerland
| | - G McBean
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublin 4Ireland
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54
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Zhao D, Mokhtari R, Pedrosa E, Birnbaum R, Zheng D, Lachman HM. Transcriptome analysis of microglia in a mouse model of Rett syndrome: differential expression of genes associated with microglia/macrophage activation and cellular stress. Mol Autism 2017; 8:17. [PMID: 28367307 PMCID: PMC5372344 DOI: 10.1186/s13229-017-0134-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/17/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Rett syndrome (RTT) is a severe, neurodevelopmental disorder primarily affecting girls, characterized by progressive loss of cognitive, social, and motor skills after a relatively brief period of typical development. It is usually due to de novo loss of function mutations in the X-linked gene, MeCP2, which codes for the gene expression and chromatin regulator, methyl-CpG binding protein 2. Although the behavioral phenotype appears to be primarily due to neuronal Mecp2 deficiency in mice, other cell types, including astrocytes and oligodendrocytes, also appear to contribute to some aspects of the RTT phenotype. In addition, microglia may also play a role. However, the effect of Mecp2 deficiency in microglia on RTT pathogenesis is controversial. METHODS In the current study, we applied whole transcriptome analysis using RNA-seq to gain insight into molecular pathways in microglia that might be dysregulated during the transition, in female mice heterozygous for an Mecp2-null allele (Mecp2+/-; Het), from the pre-phenotypic (5 weeks) to the phenotypic phases (24 weeks). RESULTS We found a significant overlap in differentially expressed genes (DEGs) with genes involved in regulating the extracellular matrix, and those that are activated or inhibited when macrophages and microglia are stimulated towards the M1 and M2 activation states. However, the M1- and M2-associated genes were different in the 5- and 24-week samples. In addition, a substantial decrease in the expression of nine members of the heat shock protein (HSP) family was found in the 5-week samples, but not at 24 weeks. CONCLUSIONS These findings suggest that microglia from pre-phenotypic and phenotypic female mice are activated in a manner different from controls and that pre-phenotypic female mice may have alterations in their capacity to response to heat stress and other stressors that function through the HSP pathway.
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Affiliation(s)
- Dejian Zhao
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA
| | - Ryan Mokhtari
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA
| | - Erika Pedrosa
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA
| | - Rayna Birnbaum
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA
| | - Deyou Zheng
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA.,Department of Neurology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA.,Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA
| | - Herbert M Lachman
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA.,Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA.,Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA.,Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY USA
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55
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Portugal CC, Socodato R, Canedo T, Silva CM, Martins T, Coreixas VSM, Loiola EC, Gess B, Röhr D, Santiago AR, Young P, Minshall RD, Paes-de-Carvalho R, Ambrósio AF, Relvas JB. Caveolin-1-mediated internalization of the vitamin C transporter SVCT2 in microglia triggers an inflammatory phenotype. Sci Signal 2017; 10:10/472/eaal2005. [PMID: 28351945 DOI: 10.1126/scisignal.aal2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vitamin C is essential for the development and function of the central nervous system (CNS). The plasma membrane sodium-vitamin C cotransporter 2 (SVCT2) is the primary mediator of vitamin C uptake in neurons. SVCT2 specifically transports ascorbate, the reduced form of vitamin C, which acts as a reducing agent. We demonstrated that ascorbate uptake through SVCT2 was critical for the homeostasis of microglia, the resident myeloid cells of the CNS that are essential for proper functioning of the nervous tissue. We found that depletion of SVCT2 from the plasma membrane triggered a proinflammatory phenotype in microglia and resulted in microglia activation. Src-mediated phosphorylation of caveolin-1 on Tyr14 in microglia induced the internalization of SVCT2. Ascorbate treatment, SVCT2 overexpression, or blocking SVCT2 internalization prevented the activation of microglia. Overall, our work demonstrates the importance of the ascorbate transport system for microglial homeostasis and hints that dysregulation of ascorbate transport might play a role in neurological disorders.
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Affiliation(s)
- Camila C Portugal
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208 4200-135 Porto, Portugal.
| | - Renato Socodato
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208 4200-135 Porto, Portugal
| | - Teresa Canedo
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208 4200-135 Porto, Portugal
| | - Cátia M Silva
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208 4200-135 Porto, Portugal
| | - Tânia Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Health Sciences Campus, Azinhaga Santa Comba, 3000-548 Coimbra, Portugal.,Center for Neuroscience and Cell Biology, Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Consortium, University of Coimbra, Coimbra, Portugal
| | - Vivian S M Coreixas
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Health Sciences Campus, Azinhaga Santa Comba, 3000-548 Coimbra, Portugal.,Department of Neurobiology and Program of Neurosciences, Institute of Biology, Fluminense Federal University, Rua Outeiro São João Batista, 24020-971 Niterói, Rio de Janeiro, Brazil
| | - Erick C Loiola
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Health Sciences Campus, Azinhaga Santa Comba, 3000-548 Coimbra, Portugal.,Department of Neurobiology and Program of Neurosciences, Institute of Biology, Fluminense Federal University, Rua Outeiro São João Batista, 24020-971 Niterói, Rio de Janeiro, Brazil
| | - Burkhard Gess
- Department of Neurology, University of Muenster, 48149 Muenster, Germany.,Department of Neurology, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany
| | - Dominik Röhr
- Department of Neurology, University of Muenster, 48149 Muenster, Germany
| | - Ana R Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Health Sciences Campus, Azinhaga Santa Comba, 3000-548 Coimbra, Portugal.,Center for Neuroscience and Cell Biology, Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Consortium, University of Coimbra, Coimbra, Portugal
| | - Peter Young
- Department of Neurology, University of Muenster, 48149 Muenster, Germany
| | - Richard D Minshall
- Department of Pharmacology and Center for Lung and Vascular Biology and Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Roberto Paes-de-Carvalho
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Fluminense Federal University, Rua Outeiro São João Batista, 24020-971 Niterói, Rio de Janeiro, Brazil
| | - António F Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Health Sciences Campus, Azinhaga Santa Comba, 3000-548 Coimbra, Portugal.,Center for Neuroscience and Cell Biology, Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Consortium, University of Coimbra, Coimbra, Portugal
| | - João B Relvas
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua Alfredo Allen, 208 4200-135 Porto, Portugal.
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56
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Shulyakova N, Andreazza AC, Mills LR, Eubanks JH. Mitochondrial Dysfunction in the Pathogenesis of Rett Syndrome: Implications for Mitochondria-Targeted Therapies. Front Cell Neurosci 2017; 11:58. [PMID: 28352216 PMCID: PMC5348512 DOI: 10.3389/fncel.2017.00058] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 02/20/2017] [Indexed: 01/20/2023] Open
Abstract
First described over 50 years ago, Rett syndrome (RTT) is a neurodevelopmental disorder caused primarily by mutations of the X-linked MECP2 gene. RTT affects predominantly females, and has a prevalence of roughly 1 in every 10,000 female births. Prior to the discovery that mutations of MECP2 are the leading cause of RTT, there were suggestions that RTT could be a mitochondrial disease. In fact, several reports documented altered mitochondrial structure, and deficiencies in mitochondrial enzyme activity in different cells or tissues derived from RTT patients. With the identification of MECP2 as the causal gene, interest largely shifted toward defining the normal function of MeCP2 in the brain, and how its absence affects the neurodevelopment and neurophysiology. Recently, though, interest in studying mitochondrial function in RTT has been reignited, at least in part due to observations suggesting systemic oxidative stress does play a contributing role in RTT pathogenesis. Here we review data relating to mitochondrial alterations at the structural and functional levels in RTT patients and model systems, and present a hypothesis for how the absence of MeCP2 could lead to altered mitochondrial function and elevated levels of cellular oxidative stress. Finally, we discuss the prospects for treating RTT using interventions that target specific aspects of mitochondrial dysfunction and/or oxidative stress.
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Affiliation(s)
- Natalya Shulyakova
- Division of Genetics and Development, Krembil Research Institute, University Health NetworkToronto, ON, Canada; Department of Physiology, University of TorontoToronto, ON, Canada
| | - Ana C Andreazza
- Department of Pharmacology, University of Toronto Toronto, ON, Canada
| | - Linda R Mills
- Department of Physiology, University of Toronto Toronto, ON, Canada
| | - James H Eubanks
- Division of Genetics and Development, Krembil Research Institute, University Health NetworkToronto, ON, Canada; Department of Physiology, University of TorontoToronto, ON, Canada; Institute of Medical Sciences, University of TorontoToronto, ON, Canada; Department of Surgery (Neurosurgery), University of TorontoToronto, ON, Canada
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57
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Cheng N, Rho JM, Masino SA. Metabolic Dysfunction Underlying Autism Spectrum Disorder and Potential Treatment Approaches. Front Mol Neurosci 2017; 10:34. [PMID: 28270747 PMCID: PMC5318388 DOI: 10.3389/fnmol.2017.00034] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 01/30/2017] [Indexed: 12/14/2022] Open
Abstract
Autism spectrum disorder (ASD) is characterized by deficits in sociability and communication, and increased repetitive and/or restrictive behaviors. While the etio-pathogenesis of ASD is unknown, clinical manifestations are diverse and many possible genetic and environmental factors have been implicated. As such, it has been a great challenge to identify key neurobiological mechanisms and to develop effective treatments. Current therapies focus on co-morbid conditions (such as epileptic seizures and sleep disturbances) and there is no cure for the core symptoms. Recent studies have increasingly implicated mitochondrial dysfunction in ASD. The fact that mitochondria are an integral part of diverse cellular functions and are susceptible to many insults could explain how a wide range of factors can contribute to a consistent behavioral phenotype in ASD. Meanwhile, the high-fat, low-carbohydrate ketogenic diet (KD), used for nearly a century to treat medically intractable epilepsy, has been shown to enhance mitochondrial function through a multiplicity of mechanisms and affect additional molecular targets that may address symptoms and comorbidities of ASD. Here, we review the evidence for the use of metabolism-based therapies such as the KD in the treatment of ASD as well as emerging co-morbid models of epilepsy and autism. Future research directions aimed at validating such therapeutic approaches and identifying additional and novel mechanistic targets are also discussed.
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Affiliation(s)
- Ning Cheng
- Departments of Pediatrics, University of CalgaryCalgary, AB, Canada
| | - Jong M. Rho
- Departments of Pediatrics, University of CalgaryCalgary, AB, Canada
- Clinical Neurosciences, University of CalgaryCalgary, AB, Canada
- Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of CalgaryCalgary, AB, Canada
| | - Susan A. Masino
- Neuroscience Program, Department of Psychology, Trinity CollegeHartford, CT, USA
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58
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Horiuchi M, Smith L, Maezawa I, Jin LW. CX 3CR1 ablation ameliorates motor and respiratory dysfunctions and improves survival of a Rett syndrome mouse model. Brain Behav Immun 2017; 60:106-116. [PMID: 26883520 PMCID: PMC5531048 DOI: 10.1016/j.bbi.2016.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/09/2016] [Accepted: 02/13/2016] [Indexed: 01/22/2023] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by loss-of-function mutations in the gene encoding MeCP2, an epigenetic modulator that binds the methyl CpG dinucleotide in target genes to regulate transcription. Previously we and others reported a role of microglia in the pathophysiology of RTT. Because microglia in the Mecp2 knockout (Mecp2KO) mouse model of RTT over-produce neurotoxic mediators glutamate and reactive oxygen species, we hypothesize that blocking neuron-microglia interaction by ablation of CX3CR1, a chemokine receptor expressed in microglia/myeloid cells mediating such interaction by pairing with its neuronal ligand CX3CL1, would ameliorate the RTT-like phenotype in Mecp2KO mice. Here we report that CX3CR1 ablation prolonged the lifespan of Mecp2KO mice from a median survival of 54.5-74days, and significantly improved the body weight gain, symptomatic scores, major respiratory parameters, and motor coordination and performance. CX3CR1 ablation rectified previously identified histological abnormalities in the Mecp2KO brain such as neuronal soma size in hippocampal CA2, and the number, soma size, and process complexity of microglia. Moreover, CX3CR1 ablation enhanced the neurotrophic action of microglia in Mecp2KO mice by producing higher amount of insulin-like growth factor 1. Our data support a role of myeloid cells/microglia in RTT and suggest a novel therapeutic approach for RTT by targeting CX3CR1 with specific antagonists or genetic downregulation.
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Affiliation(s)
- Makoto Horiuchi
- Department of Pathology and Laboratory Medicine, 2805 50th Street, UC Davis Medical Center, Sacramento, CA 95817, United States
| | - Lucas Smith
- Department of Pathology and Laboratory Medicine, 2805 50th Street, UC Davis Medical Center, Sacramento, CA 95817, United States
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine, 2805 50th Street, UC Davis Medical Center, Sacramento, CA 95817, United States,M.I.N.D. (Medical Investigation of Neurodevelopmental Disorders) Institute, 2805 50th Street, UC Davis Medical Center, Sacramento, CA 95817, United States
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, 2805 50th Street, UC Davis Medical Center, Sacramento, CA 95817, United States; M.I.N.D. (Medical Investigation of Neurodevelopmental Disorders) Institute, 2805 50th Street, UC Davis Medical Center, Sacramento, CA 95817, United States.
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59
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Cronk JC, Herz J, Kim TS, Louveau A, Moser EK, Sharma AK, Smirnov I, Tung KS, Braciale TJ, Kipnis J. Influenza A induces dysfunctional immunity and death in MeCP2-overexpressing mice. JCI Insight 2017; 2:e88257. [PMID: 28138553 PMCID: PMC5256138 DOI: 10.1172/jci.insight.88257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 12/06/2016] [Indexed: 01/10/2023] Open
Abstract
Loss of function or overexpression of methyl-CpG-binding protein 2 (MeCP2) results in the severe neurodevelopmental disorders Rett syndrome and MeCP2 duplication syndrome, respectively. MeCP2 plays a critical role in neuronal function and the function of cells throughout the body. It has been previously demonstrated that MeCP2 regulates T cell function and macrophage response to multiple stimuli, and that immune-mediated rescue imparts significant benefit in Mecp2-null mice. Unlike Rett syndrome, MeCP2 duplication syndrome results in chronic, severe respiratory infections, which represent a significant cause of patient morbidity and mortality. Here, we demonstrate that MeCP2Tg3 mice, which overexpress MeCP2 at levels 3- to 5-fold higher than normal, are hypersensitive to influenza A/PR/8/34 infection. Prior to death, MeCP2Tg3 mice experienced a host of complications during infection, including neutrophilia, increased cytokine production, excessive corticosterone levels, defective adaptive immunity, and vascular pathology characterized by impaired perfusion and pulmonary hemorrhage. Importantly, we found that radioresistant cells are essential to infection-related death after bone marrow transplantation. In all, these results demonstrate that influenza A infection in MeCP2Tg3 mice results in pathology affecting both immune and nonhematopoietic cells, suggesting that failure to effectively respond and clear viral respiratory infection has a complex, multicompartment etiology in the context of MeCP2 overexpression.
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Affiliation(s)
- James C. Cronk
- Center for Brain Immunology and Glia
- Department of Neuroscience
- Graduate Program in Neuroscience
- Medical Scientist Training Program
| | - Jasmin Herz
- Center for Brain Immunology and Glia
- Department of Neuroscience
| | - Taeg S. Kim
- Beirne B. Carter Center for Immunology Research
- Department of Pathology
| | - Antoine Louveau
- Center for Brain Immunology and Glia
- Department of Neuroscience
| | - Emily K. Moser
- Beirne B. Carter Center for Immunology Research
- Department of Pharmacology
| | | | - Igor Smirnov
- Center for Brain Immunology and Glia
- Department of Neuroscience
| | - Kenneth S. Tung
- Department of Pathology
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Thomas J. Braciale
- Medical Scientist Training Program
- Beirne B. Carter Center for Immunology Research
- Department of Pathology
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia
- Department of Neuroscience
- Graduate Program in Neuroscience
- Medical Scientist Training Program
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60
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Cortelazzo A, Pietri T, De Felice C, Leoncini S, Guerranti R, Signorini C, Timperio AM, Zolla L, Ciccoli L, Hayek J. Proteomic analysis of the Rett syndrome experimental model mecp2 Q63X mutant zebrafish. J Proteomics 2017; 154:128-133. [PMID: 28062374 DOI: 10.1016/j.jprot.2016.12.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 12/09/2016] [Accepted: 12/20/2016] [Indexed: 11/29/2022]
Abstract
Rett syndrome (RTT) is a severe genetic disorder resulting from mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene. Recently, a zebrafish carrying a mecp2-null mutation has been developed with the resulting phenotypes exhibiting defective sensory and thigmotactic responses, and abnormal motor behavior reminiscent of the human disease. Here, we performed a proteomic analysis to examine protein expression changes in mecp2-null vs. wild-type larvae and adult zebrafish. We found a total of 20 proteins differentially expressed between wild-type and mutant zebrafish, suggesting skeletal and cardiac muscle functional defects, a stunted glycolysis and depleted energy availability. This molecular evidence is directly linked to the mecp2-null zebrafish observed phenotype. In addition, we identified changes in expression of proteins critical for a proper redox balance, suggesting an enhanced oxidative stress, a phenomenon also documented in human patients and RTT murine models. The molecular alterations observed in the mecp2-null zebrafish expand our knowledge on the molecular cascade of events that lead to the RTT phenotype. BIOLOGICAL SIGNIFICANCE We performed a proteomic study of a non-mammalian vertebrate model (zebrafish, Danio rerio) for Rett syndrome (RTT) at larval and adult stages of development. Our results reveal major protein expression changes pointing out to defects in energy metabolism, redox status imbalance, and muscle function, both skeletal and cardiac. Our molecular analysis grants the mecp2-null zebrafish as a valuable RTT model, triggering new research approaches for a better understanding of the RTT pathogenesis and phenotype expression. This non-mammalian vertebrate model of RTT strongly suggests a broad impact of Mecp2 dysfunction.
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Affiliation(s)
- Alessio Cortelazzo
- Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy; Department of Medical Biotechnologies, University of Siena, Siena, Italy; Clinical Pathology Laboratory Unit, University Hospital, AOUS, Siena, Italy.
| | - Thomas Pietri
- Ecole Normale Supérieure, Institut de Biologie de l'ENS, Paris, France
| | - Claudio De Felice
- Neonatal Intensive Care Unit, University Hospital, AOUS, Siena, Italy
| | - Silvia Leoncini
- Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy; Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Roberto Guerranti
- Department of Medical Biotechnologies, University of Siena, Siena, Italy; Clinical Pathology Laboratory Unit, University Hospital, AOUS, Siena, Italy
| | - Cinzia Signorini
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Anna Maria Timperio
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
| | - Lello Zolla
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
| | - Lucia Ciccoli
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Joussef Hayek
- Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy
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Kalsbeek MJT, Mulder L, Yi CX. Microglia energy metabolism in metabolic disorder. Mol Cell Endocrinol 2016; 438:27-35. [PMID: 27687525 DOI: 10.1016/j.mce.2016.09.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/23/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022]
Abstract
Microglia are the resident macrophages of the CNS, and are in charge of maintaining a healthy microenvironment to ensure neuronal survival. Microglia carry out a non-stop patrol of the CNS, make contact with neurons and look for abnormalities, all of which requires a vast amount of energy. This non-signaling energy demand increases after activation by pathogens, neuronal damage or other kinds of stimulation. Of the three major energy substrates - glucose, fatty acids and glutamine - glucose is crucial for microglia survival and several glucose transporters are expressed to supply sufficient glucose influx. Fatty acids are another source of energy for microglia and have also been shown to strongly influence microglial immune activity. Glutamine, although possibly suitable for use as an energy substrate by microglia, has been shown to have neurotoxic effects when overloaded. Microglial fuel metabolism might be associated with microglial reactivity under different pathophysiological conditions and a microglial fuel switch may thus be the underlying cause of hypothalamic dysregulation, which is associated with obesity.
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Affiliation(s)
- Martin J T Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam (UvA), Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - Laurie Mulder
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam (UvA), Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam (UvA), Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
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Kaufmann WE, Stallworth JL, Everman DB, Skinner SA. Neurobiologically-based treatments in Rett syndrome: opportunities and challenges. Expert Opin Orphan Drugs 2016; 4:1043-1055. [PMID: 28163986 PMCID: PMC5214376 DOI: 10.1080/21678707.2016.1229181] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/23/2016] [Indexed: 12/14/2022]
Abstract
Introduction: Rett syndrome (RTT) is an X-linked neurodevelopmental disorder that primarily affects females, typically resulting in a period of developmental regression in early childhood followed by stabilization and severe chronic cognitive, behavioral, and physical disability. No known treatment exists beyond symptomatic management, and while insights into the genetic cause, pathophysiology, neurobiology, and natural history of RTT have been gained, many challenges remain. Areas covered: Based on a comprehensive survey of the primary literature on RTT, this article describes and comments upon the general and unique features of the disorder, genetic and neurobiological bases of drug development, and the history of clinical trials in RTT, with an emphasis on drug trial design, outcome measures, and implementation. Expert opinion: Neurobiologically based drug trials are the ultimate goal in RTT, and due to the complexity and global nature of the disorder, drugs targeting both general mechanisms (e.g., growth factors) and specific systems (e.g., glutamate modulators) could be effective. Trial design should optimize data on safety and efficacy, but selection of outcome measures with adequate measurement properties, as well as innovative strategies, such as those enhancing synaptic plasticity and use of biomarkers, are essential for progress in RTT and other neurodevelopmental disorders.
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Affiliation(s)
- Walter E Kaufmann
- Center for Translational Research, Greenwood Genetic Center, Greenwood, SC, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | | | - David B Everman
- Center for Translational Research, Greenwood Genetic Center , Greenwood , SC , USA
| | - Steven A Skinner
- Center for Translational Research, Greenwood Genetic Center , Greenwood , SC , USA
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Cronk JC, Derecki NC, Litvak V, Kipnis J. Unexpected cellular players in Rett syndrome pathology. Neurobiol Dis 2016; 92:64-71. [PMID: 25982834 PMCID: PMC4644494 DOI: 10.1016/j.nbd.2015.05.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/30/2015] [Accepted: 05/08/2015] [Indexed: 12/31/2022] Open
Abstract
Rett syndrome is a devastating neurodevelopmental disorder, primarily caused by mutations of methyl CpG-binding protein 2 (MeCP2). Although the genetic cause of disease was identified over a decade ago, a significant gap still remains in both our clinical and scientific understanding of its pathogenesis. Neurons are known to be primary players in pathology, with their dysfunction being the key in Rett syndrome. While studies in mice have demonstrated a clear causative - and potential therapeutic - role for neurons in Rett syndrome, recent work has suggested that other tissues also contribute significantly to progression of the disease. Indeed, Rett syndrome is known to present with several common peripheral pathologies, such as osteopenia, scoliosis, gastrointestinal problems including nutritional defects, and general growth deficit. Mouse models assessing the potential role of non-neuronal cell types have confirmed both roles in disease and potential therapeutic targets. A new picture is emerging in which neurons both initiate and drive pathology, while dysfunction of other cell types and peripheral tissues exacerbate disease, possibly amplifying further neurologic problems, and ultimately result in a positive feedback loop of progressively worsening symptoms. Here, we review what is known about neuronal and non-neuronal cell types, and discuss how this new, integrative understanding of the disease may allow for additional clinical and scientific pathways for treating and understanding Rett syndrome.
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Affiliation(s)
- James C Cronk
- Center for Brain Immunology and Glia, Department of Neuroscience, Graduate Program in Neuroscience and Medical Scientist Training Program, University of Virginia, Charlottesville, VA 22908, USA.
| | - Noel C Derecki
- Center for Brain Immunology and Glia, Department of Neuroscience, Graduate Program in Neuroscience and Medical Scientist Training Program, University of Virginia, Charlottesville, VA 22908, USA
| | - Vladimir Litvak
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia, Department of Neuroscience, Graduate Program in Neuroscience and Medical Scientist Training Program, University of Virginia, Charlottesville, VA 22908, USA.
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Schafer DP, Heller CT, Gunner G, Heller M, Gordon C, Hammond T, Wolf Y, Jung S, Stevens B. Microglia contribute to circuit defects in Mecp2 null mice independent of microglia-specific loss of Mecp2 expression. eLife 2016; 5. [PMID: 27458802 PMCID: PMC4961457 DOI: 10.7554/elife.15224] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 06/14/2016] [Indexed: 12/25/2022] Open
Abstract
Microglia, the resident CNS macrophages, have been implicated in the pathogenesis of Rett Syndrome (RTT), an X-linked neurodevelopmental disorder. However, the mechanism by which microglia contribute to the disorder is unclear and recent data suggest that microglia do not play a causative role. Here, we use the retinogeniculate system to determine if and how microglia contribute to pathogenesis in a RTT mouse model, the Mecp2 null mouse (Mecp2tm1.1Bird/y). We demonstrate that microglia contribute to pathogenesis by excessively engulfing, thereby eliminating, presynaptic inputs at end stages of disease (≥P56 Mecp2 null mice) concomitant with synapse loss. Furthermore, loss or gain of Mecp2 expression specifically in microglia (Cx3cr1CreER;Mecp2fl/yor Cx3cr1CreER; Mecp2LSL/y) had little effect on excessive engulfment, synapse loss, or phenotypic abnormalities. Taken together, our data suggest that microglia contribute to end stages of disease by dismantling neural circuits rendered vulnerable by loss of Mecp2 in other CNS cell types. DOI:http://dx.doi.org/10.7554/eLife.15224.001 Rett Syndrome is a neurodevelopmental disorder with symptoms that typically begin in girls between 6 and 18 months old. Those affected developmentally stagnate and regress – during which they lose some of their previously acquired skills and develop an array of physical impairments. Mutations in a gene called Mecp2 on the X chromosome cause most cases of Rett Syndrome. Mice that lack the Mecp2 gene develop symptoms similar to those seen in people with Rett Syndrome, and so such “Mecp2 null” mice are often used to study the disorder. Microglia, the resident immune cells of the central nervous system, have been implicated in the development of Rett Syndrome. Introducing microglia that carry the Mecp2 gene into Mecp2 null mice has been shown to reduce several disease-associated abnormalities. However, exactly how microglia contribute to these changes remains unknown. In addition, a more recent report failed to reproduce these findings, and instead obtained results suggesting that microglia do not affect the development of Rett syndrome. Schafer et al. now use the mouse visual system as a model to determine if and how microglia contribute to the development of Rett Syndrome. Like many other brain regions, the developing visual system initially has a surplus of connections between neurons, or synapses, which are subsequently pruned back. Schafer et al. previously showed in the developing visual system of early postnatal (5 days after birth) control mice (who express the Mecp2 gene) that microglia contribute to this pruning by engulfing and eliminating a subset of these excessive synaptic connections. The new experiments by Schafer et al. show that another wave of microglia-mediated synaptic pruning occurs in 40-day-old juvenile control mice. Because Mecp2 null mice begin to display features of Rett Syndrome when they’re about 40 days old, Schafer et al. tested whether the microglia of these animals inappropriately prune synaptic connections. While this process occurred normally in neonatal and juvenile Mecp2 null mice, microglia began to excessively engulf cells in Mecp2 null mice when they were around 56 days old. Unexpectedly, deleting or reintroducing the Mecp2 gene solely in the microglia of these mice had little effect on pruning activity of the microglia, and failed to affect Rett-syndrome-like symptoms in the mice. Taken together, the data presented by Schafer et al. suggest how microglia contribute to the final stages of Rett Syndrome: by dismantling circuits of neurons that are rendered vulnerable by the loss of the Mecp2 gene in other cell types. DOI:http://dx.doi.org/10.7554/eLife.15224.002
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Affiliation(s)
- Dorothy P Schafer
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Christopher T Heller
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Georgia Gunner
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Department of Neurobiology, University of Massachusetts Medical School, Worcester, United States
| | - Molly Heller
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States
| | - Christopher Gordon
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States
| | - Timothy Hammond
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States
| | - Yochai Wolf
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Steffen Jung
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Beth Stevens
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
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Abstract
Rett syndrome is an extremely disabling X-linked nervous system disorder that mainly affects girls in early childhood and causes autism-like behavior, severe intellectual disability, seizures, sleep disturbances, autonomic instability, and other disorders due to mutations in the MeCP2 (methyl CpG-binding protein 2) transcription factor. The disorder targets synapses and synaptic plasticity and has been shown to disrupt the balance between glutamate excitatory synapses and GABAergic inhibitory synapses. In fact, it can be argued that Rett syndrome is primarily a disorder of synaptic plasticity and that agents that can correct this imbalance may have beneficial effects on brain development. This review briefly summarizes the link between disrupted synaptic plasticity mechanisms and Rett syndrome and early clinical trials that aim to target these abnormalities to improve the outcome for these severely disabled children.
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Affiliation(s)
- Michael Johnston
- Developmental Neuroscience Laboratory, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, USA; Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mary E Blue
- Developmental Neuroscience Laboratory, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sakkubai Naidu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Cuddapah VA, Sinifunanya EN, Percy AK, Olsen ML. MeCP2 in the regulation of neural activity: Rett syndrome pathophysiological perspectives. Degener Neurol Neuromuscul Dis 2015; 5:103-116. [PMID: 32669918 PMCID: PMC7337177 DOI: 10.2147/dnnd.s61269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/23/2015] [Indexed: 11/23/2022] Open
Abstract
Rett syndrome (RTT), an X-linked neurodevelopment disorder, occurs in approximately one out of 10,000 females. Individuals afflicted by RTT display a constellation of signs and symptoms, affecting nearly every organ system. Most striking are the neurological manifestations, including regression of language and motor skills, increased seizure activity, autonomic dysfunction, and aberrant regulation of breathing patterns. The majority of girls with RTT have mutations in the gene encoding for methyl-CpG binding protein 2 (MeCP2). Since the discovery of this genetic cause of RTT in 1999, there has been an accelerated pace of research seeking to understand the role of MeCP2 in the brain in the hope of developing a disease-modifying therapy for RTT. In this study, we review the clinical features of RTT and then explore the latest mechanistic studies in order to explain how a mutation in MeCP2 leads to these unique features. We cover in detail studies examining the role of MeCP2 in neuronal physiology, as well as recent evidence that implicates a key role for glia in the pathogenesis of RTT. In the past 20 years, these basic and clinical studies have yielded an extraordinary understanding of RTT; as such, we end this narrative review considering the translation of these studies into clinical trials for the treatment of RTT.
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Affiliation(s)
| | | | - Alan K Percy
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
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