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Dong HW, Weiss K, Baugh K, Meadows MJ, Niswender CM, Neul JL. Potentiation of the muscarinic acetylcholine receptor 1 modulates neurophysiological features in a mouse model of Rett syndrome. Neurotherapeutics 2024; 21:e00384. [PMID: 38880672 DOI: 10.1016/j.neurot.2024.e00384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/07/2024] [Accepted: 06/09/2024] [Indexed: 06/18/2024] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder primarily caused by mutations in the X chromosome-linked gene Methyl-CpG Binding Protein 2 (MECP2). Restoring MeCP2 expression after disease onset in a mouse model of RTT reverses phenotypes, providing hope for development of treatments for RTT. Translatable biomarkers of improvement and treatment responses have the potential to accelerate both preclinical and clinical evaluation of targeted therapies in RTT. Studies in people with and mouse models of RTT have identified neurophysiological features, such as auditory event-related potentials, that correlate with disease severity, suggesting that they could be useful as biomarkers of disease improvement or early treatment response. We recently demonstrated that treatment of RTT mice with a positive allosteric modulator (PAM) of muscarinic acetylcholine subtype 1 receptor (M1) improved phenotypes, suggesting that modulation of M1 activity is a potential therapy in RTT. To evaluate whether neurophysiological features could be useful biomarkers to assess the effects of M1 PAM treatment, we acutely administered the M1 PAM VU0486846 (VU846) at doses of 1, 3, 10 and 30 mg/kg in wildtype and RTT mice. This resulted in an inverted U-shaped dose response with maximal improvement of AEP features at 3 mg/kg but with no marked effect on basal EEG power or epileptiform discharges in RTT mice and no significant changes in wildtype mice. These findings suggest that M1 potentiation can improve neural circuit synchrony to auditory stimuli in RTT mice and that neurophysiological features have potential as pharmacodynamic or treatment-responsive biomarkers for preclinical and clinical evaluation of putative therapies in RTT.
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Affiliation(s)
- Hong-Wei Dong
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, USA; Vanderbilt University Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kelly Weiss
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, USA; Warren Center for Neuroscience Drug Discovery, School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Kathryn Baugh
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, USA
| | - Mac J Meadows
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, USA; Warren Center for Neuroscience Drug Discovery, School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Colleen M Niswender
- Vanderbilt University Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, USA; Warren Center for Neuroscience Drug Discovery, School of Medicine, Vanderbilt University, Nashville, TN, USA; Vanderbilt Institute for Chemical Biology, Nashville, TN, USA; Vanderbilt Brain Institute, Nashville, TN, USA.
| | - Jeffrey L Neul
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, USA; Vanderbilt University Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, USA; Vanderbilt Brain Institute, Nashville, TN, USA.
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Medeiros D, Ayala-Baylon K, Egido-Betancourt H, Miller E, Chapleau C, Robinson H, Phillips ML, Yang T, Longo FM, Li W, Pozzo-Miller L. A small-molecule TrkB ligand improves dendritic spine phenotypes and atypical behaviors in female Rett syndrome mice. Dis Model Mech 2024; 17:dmm050612. [PMID: 38785269 PMCID: PMC11139040 DOI: 10.1242/dmm.050612] [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: 11/17/2023] [Accepted: 03/06/2024] [Indexed: 05/25/2024] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in MECP2, which encodes methyl-CpG-binding protein 2, a transcriptional regulator of many genes, including brain-derived neurotrophic factor (BDNF). BDNF levels are lower in multiple brain regions of Mecp2-deficient mice, and experimentally increasing BDNF levels improve atypical phenotypes in Mecp2 mutant mice. Due to the low blood-brain barrier permeability of BDNF itself, we tested the effects of LM22A-4, a brain-penetrant, small-molecule ligand of the BDNF receptor TrkB (encoded by Ntrk2), on dendritic spine density and form in hippocampal pyramidal neurons and on behavioral phenotypes in female Mecp2 heterozygous (HET) mice. A 4-week systemic treatment of Mecp2 HET mice with LM22A-4 restored spine volume in MeCP2-expressing neurons to wild-type (WT) levels, whereas spine volume in MeCP2-lacking neurons remained comparable to that in neurons from female WT mice. Female Mecp2 HET mice engaged in aggressive behaviors more than WT mice, the levels of which were reduced to WT levels by the 4-week LM22A-4 treatment. These data provide additional support to the potential usefulness of novel therapies not only for RTT but also to other BDNF-related disorders.
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Affiliation(s)
- Destynie Medeiros
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Karen Ayala-Baylon
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Hailey Egido-Betancourt
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Eric Miller
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Christopher Chapleau
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Holly Robinson
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mary L. Phillips
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Tao Yang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Frank M. Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wei Li
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Cooper MS, Macdonald-Laurs E, Antolovich GC. Cerebral palsy: A neurodevelopmental disorder with motor disability. Dev Med Child Neurol 2024. [PMID: 38760996 DOI: 10.1111/dmcn.15960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/20/2024]
Affiliation(s)
- Monica S Cooper
- The Royal Children's Hospital Melbourne, Department of Neurodevelopment & Disability, Parkville, Victoria, Australia
| | - Emma Macdonald-Laurs
- The Royal Children's Hospital Melbourne, Department of Neurology, Parkville, Victoria, Australia
| | - Giuliana C Antolovich
- The Royal Children's Hospital Melbourne, Department of Neurodevelopment & Disability, Parkville, Victoria, Australia
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Acharya P, Choi NY, Shrestha S, Jeong S, Lee MY. Brain organoids: A revolutionary tool for modeling neurological disorders and development of therapeutics. Biotechnol Bioeng 2024; 121:489-506. [PMID: 38013504 PMCID: PMC10842775 DOI: 10.1002/bit.28606] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 10/03/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023]
Abstract
Brain organoids are self-organized, three-dimensional (3D) aggregates derived from pluripotent stem cells that have cell types and cellular architectures resembling those of the developing human brain. The current understanding of human brain developmental processes and neurological disorders has advanced significantly with the introduction of this in vitro model. Brain organoids serve as a translational link between two-dimensional (2D) cultures and in vivo models which imitate the neural tube formation at the early and late stages and the differentiation of neuroepithelium with whole-brain regionalization. In addition, the generation of region-specific brain organoids made it possible to investigate the pathogenic and etiological aspects of acquired and inherited brain disease along with drug discovery and drug toxicity testing. In this review article, we first summarize an overview of the existing methods and platforms used for generating brain organoids and their limitations and then discuss the recent advancement in brain organoid technology. In addition, we discuss how brain organoids have been used to model aspects of neurodevelopmental and neurodegenerative diseases, including autism spectrum disorder (ASD), Rett syndrome, Zika virus-related microcephaly, Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD).
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Affiliation(s)
- Prabha Acharya
- Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
| | - Na Young Choi
- Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
- Department of Healthcare Information Technology, Inje University, Gimhae, Republic of Korea
| | - Sunil Shrestha
- Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
| | - Sehoon Jeong
- Department of Healthcare Information Technology, Inje University, Gimhae, Republic of Korea
| | - Moo-Yeal Lee
- Department of Biomedical Engineering, University of North Texas, Denton, Texas, USA
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Siqueira E, Kim BH, Reser L, Chow R, Delaney K, Esteller M, Ross MM, Shabanowitz J, Hunt DF, Guil S, Ausió J. Analysis of the interplay between MeCP2 and histone H1 during in vitro differentiation of human ReNCell neural progenitor cells. Epigenetics 2023; 18:2276425. [PMID: 37976174 PMCID: PMC10769555 DOI: 10.1080/15592294.2023.2276425] [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: 06/13/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023] Open
Abstract
An immortalized neural cell line derived from the human ventral mesencephalon, called ReNCell, and its MeCP2 knock out were used. With it, we characterized the chromatin compositional transitions undergone during differentiation, with special emphasis on linker histones. While the WT cells displayed the development of dendrites and axons the KO cells did not, despite undergoing differentiation as monitored by NeuN. ReNCell expressed minimal amounts of histone H1.0 and their linker histone complement consisted mainly of histone H1.2, H1.4 and H1.5. The overall level of histone H1 exhibited a trend to increase during the differentiation of MeCP2 KO cells. The phosphorylation levels of histone H1 proteins decreased dramatically during ReNCell's cell differentiation independently of the presence of MeCP2. Immunofluorescence analysis showed that MeCP2 exhibits an extensive co-localization with linker histones. Interestingly, the average size of the nucleus decreased during differentiation but in the MeCP2 KO cells, the smaller size of the nuclei at the start of differentiation increased by almost 40% after differentiation by 8 days (8 DIV). In summary, our data provide a compelling perspective on the dynamic changes of H1 histones during neural differentiation, coupled with the intricate interplay between H1 variants and MeCP2.Abbreviations: ACN, acetonitrile; A230, absorbance at 230 nm; bFGF, basic fibroblast growth factor; CM, chicken erythrocyte histone marker; CNS, central nervous system; CRISPR, clustered regulated interspaced short palindromic repeatsDAPI, 4,'6-diaminidino-2-phenylindole; DIV, days in vitro (days after differentiation is induced); DMEM, Dulbecco's modified Eagle medium; EGF, epidermal growth factor; ESC, embryonic stem cell; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GFAP, glial fibrillary acidic proteinHPLC, high-performance liquid chromatography; IF, immunofluorescence; iPSCs, induced pluripotent stem cells; MAP2, microtubule-associated protein 2; MBD, methyl-binding domain; MeCP2, methyl-CpG binding protein 2; MS, mass spectrometry; NCP, nucleosome core particle; NeuN, neuron nuclear antigen; NPC, neural progenitor cellPAGE, polyacrylamide gel electrophoresis; PBS, phosphate buffered saline; PFA, paraformaldehyde; PTM, posttranslational modification; RP-HPLC, reversed phase HPLC; ReNCells, ReNCells VM; RPLP0, ribosomal protein lateral stalk subunit P0; RT-qPCR, reverse transcription quantitative polymerase-chain reaction; RTT, Rett Syndrome; SDS, sodium dodecyl sulphate; TAD, topologically associating domain; Triple KO, triple knockout.
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Affiliation(s)
- Edilene Siqueira
- Josep Carreras Leukaemia Research Institute (IJC), Badalona, Barcelona, Catalonia, Spain
- National Council for Scientific and Technological Development (CNPq), Brasilia, Federal District, Brazil
| | - Bo-Hyun Kim
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Larry Reser
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - Robert Chow
- Department of Biology, University of Victoria, Victoria, BC, Canada
| | - Kerry Delaney
- Department of Biology, University of Victoria, Victoria, BC, Canada
| | - Manel Esteller
- Josep Carreras Leukaemia Research Institute (IJC), Badalona, Barcelona, Catalonia, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain
- Physiological Sciences Department, School of Medicine and Health Sciences, University of Barcelona (UB), Barcelona, Catalonia, Spain
| | - Mark M. Ross
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - Donald F. Hunt
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
- Department of Pathology, University of Virginia, Charlottesville, Virginia, USA
| | - Sonia Guil
- Josep Carreras Leukaemia Research Institute (IJC), Badalona, Barcelona, Catalonia, Spain
- GermansTrias i Pujol Health Science Research Institute, Badalona, Barcelona, Catalonia, Spain
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
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Medeiros D, Ayala-Baylon K, Egido-Betancourt H, Miller E, Chapleau CA, Robinson HA, Phillips ML, Yang T, Longo F, Li W, Pozzo-Miller L. A small-molecule TrkB ligand improves dendritic spine phenotypes and atypical behaviors in female Rett syndrome mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566435. [PMID: 37986936 PMCID: PMC10659425 DOI: 10.1101/2023.11.09.566435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in methyl-CpG-binding protein-2 (MECP2), encoding a transcriptional regulator of many genes, including brain-derived neurotrophic factor (Bdnf). BDNF mRNA and protein levels are lower in RTT autopsy brains and in multiple brain regions of Mecp2-deficient mice, and experimentally increasing BDNF levels improve atypical phenotypes in Mecp2 mutant mice. Due to the low blood-brain barrier permeability of BDNF itself, we tested the effects of a brain penetrant, small molecule ligand of its TrkB receptors. Applied in vitro, LM22A-4 increased dendritic spine density in pyramidal neurons in cultured hippocampal slices from postnatal day (P) 7 male Mecp2 knockout (KO) mice as much as recombinant BDNF, and both effects were prevented by the TrkB receptor inhibitors K-252a and ANA-12. Consistent with its partial agonist activity, LM22A-4 did not affect spine density in CA1 pyramidal neurons in slice cultures from male wildtype (WT) mice, where typical BDNF levels outcompete its binding to TrkB. To identify neurons of known genotypes in the "mosaic" brain of female Mecp2 heterozygous (HET) mice, we treated 4-6-month-old female MeCP2-GFP WT and HET mice with peripheral injections of LM22A-4 for 4 weeks. Surprisingly, mutant neurons lacking MeCP2-GFP showed dendritic spine volumes comparable to that in WT controls, while MeCP2-GFP-expressing neurons showed larger spines, similar to the phenotype we described in symptomatic male Mecp2 KO mice where all neurons lack MeCP2. Consistent with this non-cell-autonomous mechanism, a 4-week systemic treatment with LM22A-4 had an effect only in MeCP2-GFP-expressing neurons in female Mecp2 HET mice, bringing dendritic spine volumes down to WT control levels, and without affecting spines of MeCP2-GFP-lacking neurons. At the behavioral level, we found that female Mecp2 HET mice engaged in aggressive behaviors significantly more than WT controls, which were reduced to WT levels by a 4-week systemic treatment with LM22A-4. Altogether, these data revealed differences in dendritic spine size and altered behaviors in Mecp2 HET mice, while providing support to the potential usefulness of BDNF-related therapeutic approaches such as the partial TrkB agonist LM22A-4.
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Stott J, Wright T, Holmes J, Wilson J, Griffiths-Jones S, Foster D, Wright B. A systematic review of non-coding RNA genes with differential expression profiles associated with autism spectrum disorders. PLoS One 2023; 18:e0287131. [PMID: 37319303 PMCID: PMC10270643 DOI: 10.1371/journal.pone.0287131] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 05/30/2023] [Indexed: 06/17/2023] Open
Abstract
AIMS To identify differential expression of shorter non-coding RNA (ncRNA) genes associated with autism spectrum disorders (ASD). BACKGROUND ncRNA are functional molecules that derive from non-translated DNA sequence. The HUGO Gene Nomenclature Committee (HGNC) have approved ncRNA gene classes with alignment to the reference human genome. One subset is microRNA (miRNA), which are highly conserved, short RNA molecules that regulate gene expression by direct post-transcriptional repression of messenger RNA. Several miRNA genes are implicated in the development and regulation of the nervous system. Expression of miRNA genes in ASD cohorts have been examined by multiple research groups. Other shorter classes of ncRNA have been examined less. A comprehensive systematic review examining expression of shorter ncRNA gene classes in ASD is timely to inform the direction of research. METHODS We extracted data from studies examining ncRNA gene expression in ASD compared with non-ASD controls. We included studies on miRNA, piwi-interacting RNA (piRNA), small NF90 (ILF3) associated RNA (snaR), small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), transfer RNA (tRNA), vault RNA (vtRNA) and Y RNA. The following electronic databases were searched: Cochrane Library, EMBASE, PubMed, Web of Science, PsycINFO, ERIC, AMED and CINAHL for papers published from January 2000 to May 2022. Studies were screened by two independent investigators with a third resolving discrepancies. Data was extracted from eligible papers. RESULTS Forty-eight eligible studies were included in our systematic review with the majority examining miRNA gene expression alone. Sixty-four miRNA genes had differential expression in ASD compared to controls as reported in two or more studies, but often in opposing directions. Four miRNA genes had differential expression in the same direction in the same tissue type in at least 3 separate studies. Increased expression was reported in miR-106b-5p, miR-155-5p and miR-146a-5p in blood, post-mortem brain, and across several tissue types, respectively. Decreased expression was reported in miR-328-3p in bloods samples. Seven studies examined differential expression from other classes of ncRNA, including piRNA, snRNA, snoRNA and Y RNA. No individual ncRNA genes were reported in more than one study. Six studies reported differentially expressed snoRNA genes in ASD. A meta-analysis was not possible because of inconsistent methodologies, disparate tissue types examined, and varying forms of data presented. CONCLUSION There is limited but promising evidence associating the expression of certain miRNA genes and ASD, although the studies are of variable methodological quality and the results are largely inconsistent. There is emerging evidence associating differential expression of snoRNA genes in ASD. It is not currently possible to say whether the reports of differential expression in ncRNA may relate to ASD aetiology, a response to shared environmental factors linked to ASD such as sleep and nutrition, other molecular functions, human diversity, or chance findings. To improve our understanding of any potential association, we recommend improved and standardised methodologies and reporting of raw data. Further high-quality research is required to shine a light on possible associations, which may yet yield important information.
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Affiliation(s)
- Jon Stott
- Child Oriented Mental Health Intervention Collaborative (COMIC), University of York in Collaboration with Leeds and York Partnership NHS Foundation Trust, York, United Kingdom
- Tees, Esk & Wear Valleys NHS Foundation Trust, Foss Park Hospital, York, United Kingdom
| | - Thomas Wright
- Manchester Centre for Genomic Medicine, Clinical Genetics Service, Saint Mary’s Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Jannah Holmes
- Child Oriented Mental Health Intervention Collaborative (COMIC), University of York in Collaboration with Leeds and York Partnership NHS Foundation Trust, York, United Kingdom
- Hull York Medical School, University of York, Heslington, York, United Kingdom
| | - Julie Wilson
- Department of Mathematics, University of York, Heslington, York, United Kingdom
| | - Sam Griffiths-Jones
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Deborah Foster
- Tees, Esk & Wear Valleys NHS Foundation Trust, Foss Park Hospital, York, United Kingdom
| | - Barry Wright
- Child Oriented Mental Health Intervention Collaborative (COMIC), University of York in Collaboration with Leeds and York Partnership NHS Foundation Trust, York, United Kingdom
- Hull York Medical School, University of York, Heslington, York, United Kingdom
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Palmieri M, Pozzer D, Landsberger N. Advanced genetic therapies for the treatment of Rett syndrome: state of the art and future perspectives. Front Neurosci 2023; 17:1172805. [PMID: 37304036 PMCID: PMC10248472 DOI: 10.3389/fnins.2023.1172805] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Loss and gain of functions mutations in the X-linked MECP2 (methyl-CpG-binding protein 2) gene are responsible for a set of generally severe neurological disorders that can affect both genders. In particular, Mecp2 deficiency is mainly associated with Rett syndrome (RTT) in girls, while duplication of the MECP2 gene leads, mainly in boys, to the MECP2 duplication syndrome (MDS). No cure is currently available for MECP2 related disorders. However, several studies have reported that by re-expressing the wild-type gene is possible to restore defective phenotypes of Mecp2 null animals. This proof of principle endorsed many laboratories to search for novel therapeutic strategies to cure RTT. Besides pharmacological approaches aimed at modulating MeCP2-downstream pathways, genetic targeting of MECP2 or its transcript have been largely proposed. Remarkably, two studies focused on augmentative gene therapy were recently approved for clinical trials. Both use molecular strategies to well-control gene dosage. Notably, the recent development of genome editing technologies has opened an alternative way to specifically target MECP2 without altering its physiological levels. Other attractive approaches exclusively applicable for nonsense mutations are the translational read-through (TR) and t-RNA suppressor therapy. Reactivation of the MECP2 locus on the silent X chromosome represents another valid choice for the disease. In this article, we intend to review the most recent genetic interventions for the treatment of RTT, describing the current state of the art, and the related advantages and concerns. We will also discuss the possible application of other advanced therapies, based on molecular delivery through nanoparticles, already proposed for other neurological disorders but still not tested in RTT.
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Affiliation(s)
- Michela Palmieri
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Diego Pozzer
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Nicoletta Landsberger
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Faculty of Medicine and Surgery, University of Milan, Milan, Italy
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Patel PA, Hegert JV, Cristian I, Kerr A, LaConte LEW, Fox MA, Srivastava S, Mukherjee K. Complete loss of the X-linked gene CASK causes severe cerebellar degeneration. J Med Genet 2022; 59:1044-1057. [PMID: 35149592 DOI: 10.1136/jmedgenet-2021-108115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 01/13/2022] [Indexed: 01/19/2023]
Abstract
BACKGROUND Heterozygous loss of X-linked genes like CASK and MeCP2 (Rett syndrome) causes developmental delay in girls, while in boys, loss of the only allele of these genes leads to epileptic encephalopathy. The mechanism for these disorders remains unknown. CASK-linked cerebellar hypoplasia is presumed to result from defects in Tbr1-reelin-mediated neuronal migration. METHOD Here we report clinical and histopathological analyses of a deceased 2-month-old boy with a CASK-null mutation. We next generated a mouse line where CASK is completely deleted (hemizygous and homozygous) from postmigratory neurons in the cerebellum. RESULT The CASK-null human brain was smaller in size but exhibited normal lamination without defective neuronal differentiation, migration or axonal guidance. The hypoplastic cerebellum instead displayed astrogliosis and microgliosis, which are markers for neuronal loss. We therefore hypothesise that CASK loss-induced cerebellar hypoplasia is the result of early neurodegeneration. Data from the murine model confirmed that in CASK loss, a small cerebellum results from postdevelopmental degeneration of cerebellar granule neurons. Furthermore, at least in the cerebellum, functional loss from CASK deletion is secondary to degeneration of granule cells and not due to an acute molecular functional loss of CASK. Intriguingly, female mice with heterozygous deletion of CASK in the cerebellum do not display neurodegeneration. CONCLUSION We suggest that X-linked neurodevelopmental disorders like CASK mutation and Rett syndrome are pathologically neurodegenerative; random X-chromosome inactivation in heterozygous mutant girls, however, results in 50% of cells expressing the functional gene, resulting in a non-progressive pathology, whereas complete loss of the only allele in boys leads to unconstrained degeneration and encephalopathy.
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Affiliation(s)
- Paras A Patel
- Fralin Biomedical Research Institute at VTC, Roanoke, Virginia, USA
| | - Julia V Hegert
- Department of Pathology, Orlando Health, Orlando, Florida, USA
| | | | - Alicia Kerr
- Fralin Biomedical Research Institute at VTC, Roanoke, Virginia, USA
| | | | - Michael A Fox
- Fralin Biomedical Research Institute at VTC, Roanoke, Virginia, USA.,School of Neuroscience, Blacksburg, Virginia, USA
| | - Sarika Srivastava
- Fralin Biomedical Research Institute at VTC, Roanoke, Virginia, USA.,Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA
| | - Konark Mukherjee
- Fralin Biomedical Research Institute at VTC, Roanoke, Virginia, USA .,Department of Psychiatry, Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA
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Loss of O-GlcNAcylation on MeCP2 at Threonine 203 Leads to Neurodevelopmental Disorders. Neurosci Bull 2021; 38:113-134. [PMID: 34773221 PMCID: PMC8821740 DOI: 10.1007/s12264-021-00784-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/06/2021] [Indexed: 02/03/2023] Open
Abstract
Mutations of the X-linked methyl-CpG-binding protein 2 (MECP2) gene in humans are responsible for most cases of Rett syndrome (RTT), an X-linked progressive neurological disorder. While genome-wide screens in clinical trials have revealed several putative RTT-associated mutations in MECP2, their causal relevance regarding the functional regulation of MeCP2 at the etiologic sites at the protein level requires more evidence. In this study, we demonstrated that MeCP2 was dynamically modified by O-linked-β-N-acetylglucosamine (O-GlcNAc) at threonine 203 (T203), an etiologic site in RTT patients. Disruption of the O-GlcNAcylation of MeCP2 specifically at T203 impaired dendrite development and spine maturation in cultured hippocampal neurons, and disrupted neuronal migration, dendritic spine morphogenesis, and caused dysfunction of synaptic transmission in the developing and juvenile mouse cerebral cortex. Mechanistically, genetic disruption of O-GlcNAcylation at T203 on MeCP2 decreased the neuronal activity-induced induction of Bdnf transcription. Our study highlights the critical role of MeCP2 T203 O-GlcNAcylation in neural development and synaptic transmission potentially via brain-derived neurotrophic factor.
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Lotan M, Ippolito E, Favetta M, Romano A. Skype Supervised, Individualized, Home-Based Rehabilitation Programs for Individuals With Rett Syndrome and Their Families - Parental Satisfaction and Point of View. Front Psychol 2021; 12:720927. [PMID: 34603144 PMCID: PMC8481588 DOI: 10.3389/fpsyg.2021.720927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/19/2021] [Indexed: 11/23/2022] Open
Abstract
Individuals with Rett syndrome (RTT) experience impaired gross motor skills limiting their capacity. Therefore, they need support to participate in physical activities, and it is crucial to work with primary caregivers when developing appropriate strategies, thereby leading to an active lifestyle. There is limited evidence supporting the effectiveness of remotely supported physical activity interventions. This project aimed to evaluate the effects of a skype-based, telehealth-delivered physical activity program carried out by participants’ parents at home. This article will focus on parental points of view. A mixed-methods design evaluating parental satisfaction was conducted. Forty participants with a confirmed genetic diagnosis of RTT and their families were recruited. The intervention included a 12-week individualized daily physical activity program carried out by participants’ parents and bi-weekly supervised by expert therapists. Parents’ impressions and feelings related to the program implementation were collected throughout semi-structured interviews, and an ad hoc developed questionnaire and discussed. The current project results suggest that a remote physical rehabilitation program, supported fortnightly by video calls, represents an effective way of conducting a remote physical therapy intervention for this population and that it can be easily carried out at home by primary caregivers, promoting positive functional changes, without bringing feelings of frustration due to the required workload. The strategies that families have learned during the program to support the motor activities of their daughters represent an easily performed set of tools that they can maintain and use in everyday life even after the cessation of the program.
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Affiliation(s)
- Meir Lotan
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel.,Israeli Rett Syndrome National Evaluation Team, Sheba Hospital, Ramat-Gan, Israel
| | | | - Martina Favetta
- Motion Analysis and Robotics Laboratory, Unit of Neurorehabilitation, Department of Neuroscience, Bambino Gesù Children's Hospital, Rome, Italy
| | - Alberto Romano
- SMART Learning Center, Milan, Italy.,Motion Analysis and Robotics Laboratory, Unit of Neurorehabilitation, Department of Neuroscience, Bambino Gesù Children's Hospital, Rome, Italy.,Centro AIRETT Ricerca e Innovazione (CARI), Research and Innovation Airett Center, Verona, Italy
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12
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Signorini C, Leoncini S, Durand T, Galano JM, Guy A, Bultel-Poncé V, Oger C, Lee JCY, Ciccoli L, Hayek J, De Felice C. Circulating 4-F 4t-Neuroprostane and 10-F 4t-Neuroprostane Are Related to MECP2 Gene Mutation and Natural History in Rett Syndrome. Int J Mol Sci 2021; 22:ijms22084240. [PMID: 33921863 PMCID: PMC8073126 DOI: 10.3390/ijms22084240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/10/2021] [Accepted: 04/15/2021] [Indexed: 12/20/2022] Open
Abstract
Neuroprostanes, a family of non-enzymatic metabolites of the docosahexaenoic acid, have been suggested as potential biomarkers for neurological diseases. Objective biological markers are strongly needed in Rett syndrome (RTT), which is a progressive X-linked neurodevelopmental disorder that is mainly caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene with a predominant multisystemic phenotype. The aim of the study is to assess a possible association between MECP2 mutations or RTT disease progression and plasma levels of 4(RS)-4-F4t-neuroprostane (4-F4t-NeuroP) and 10(RS)-10-F4t-neuroprostane (10-F4t-NeuroP) in typical RTT patients with proven MECP2 gene mutation. Clinical severity and disease progression were assessed using the Rett clinical severity scale (RCSS) in n = 77 RTT patients. The 4-F4t-NeuroP and 10-F4t-NeuroP molecules were totally synthesized and used to identify the contents of the plasma of the patients. Neuroprostane levels were related to MECP2 mutation category (i.e., early truncating, gene deletion, late truncating, and missense), specific hotspot mutations (i.e., R106W, R133C, R168X, R255X, R270X, R294X, R306C, and T158M), and disease stage (II through IV). Circulating 4-F4t-NeuroP and 10-F4t-NeuroP were significantly related to (i) the type of MECP2 mutations where higher levels were associated to gene deletions (p ≤ 0.001); (ii) severity of common hotspot MECP2 mutation (large deletions, R168X, R255X, and R270X); (iii) disease stage, where higher concentrations were observed at stage II (p ≤ 0.002); and (iv) deficiency in walking (p ≤ 0.0003). This study indicates the biological significance of 4-F4t-NeuroP and 10-F4t-NeuroP as promising molecules to mark the disease progression and potentially gauge genotype-phenotype associations in RTT.
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Affiliation(s)
- Cinzia Signorini
- Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy;
- Correspondence: (C.S.); (C.D.F.); Tel.: +39-0577-234499 (C.S.)
| | - Silvia Leoncini
- Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, 53100 Siena, Italy;
- Child Neuropsychiatry Unit, Azienda Ospedaliera Universitaria Senese, 53100 Siena, Italy;
| | - Thierry Durand
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Jean-Marie Galano
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Alexandre Guy
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Valérie Bultel-Poncé
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Camille Oger
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | | | - Lucia Ciccoli
- 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
| | - Claudio De Felice
- Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, 53100 Siena, Italy;
- Correspondence: (C.S.); (C.D.F.); Tel.: +39-0577-234499 (C.S.)
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Abstract
Epilepsy is a common neurological disorder characterized by recurrent and
unprovoked seizures due to neuronal hyperactivity. A large proportion
of epilepsy cases begin during childhood. Causes of epilepsy include
stroke, infections, brain injury, genetic factors, or other factors
that alter brain structure and development, but in up to 50% of cases
the cause is unknown. Approximately 35% of patients have refractory
seizures that do not respond to medication. Animal models and in vitro
cultures have contributed to our understanding of epilepsy, but there
is a clear need for better models to explore the human brain in normal
and pathological conditions. Human pluripotent stem cell (PSC)
technologies opened the door for new models for analyzing brain
development and disease, especially conditions with a genetic
component. Initially, PSCs were differentiated into 2-dimensional
cultures of a homogenous population of neural cells, such as
glutamatergic excitatory or γ-aminobutyric acidergic inhibitory
neurons, as well as glial cells. Nevertheless, these cultures lacked
the structure and complexity of a human brain. In the last decade, PSC
technology has advanced to the next level through the development of
3-dimensional culture, called organoids. These organoids recapitulate
features of the human brain that are missing in animal models,
enabling a deeper study of the human brain. In this review, we will
summarize the current status of organoid research and its application
to epilepsy.
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Affiliation(s)
- Vanesa Nieto-Estévez
- Department of Biology and Brain Health Consortium, 414492The University of Texas at San Antonio, TX, USA
| | - Jenny Hsieh
- Department of Biology and Brain Health Consortium, 414492The University of Texas at San Antonio, TX, USA
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14
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Functional Network Mapping Reveals State-Dependent Response to IGF1 Treatment in Rett Syndrome. Brain Sci 2020; 10:brainsci10080515. [PMID: 32756423 PMCID: PMC7465931 DOI: 10.3390/brainsci10080515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 01/20/2023] Open
Abstract
Rett Syndrome (RTT) is a neurodevelopmental disorder associated with mutations in the gene MeCP2, which is involved in the development and function of cortical networks. The clinical presentation of RTT is generally severe and includes developmental regression and marked neurologic impairment. Insulin-Like growth factor 1 (IGF1) ameliorates RTT-relevant phenotypes in animal models and improves some clinical manifestations in early human trials. However, it remains unclear whether IGF1 treatment has an impact on cortical electrophysiology in line with MeCP2’s role in network formation, and whether these electrophysiological changes are related to clinical response. We performed clinical assessments and resting-state electroencephalogram (EEG) recordings in eighteen patients with classic RTT, nine of whom were treated with IGF1. Among the treated patients, we distinguished those who showed improvements after treatment (responders) from those who did not show any changes (nonresponders). Clinical assessments were carried out for all individuals with RTT at baseline and 12 months after treatment. Network measures were derived using statistical modelling techniques based on interelectrode coherence measures. We found significant interaction between treatment groups and timepoints, indicating an effect of IGF1 on network measures. We also found a significant effect of responder status and timepoint, indicating that these changes in network measures are associated with clinical response to treatment. Further, we found baseline variability in network characteristics, and a machine learning model using these measures applied to pretreatment data predicted treatment response with 100% accuracy (100% sensitivity and 100% specificity) in this small patient group. These results highlight the importance of network pathology in RTT, as well as providing preliminary evidence for the potential of network measures as tools for the characterisation of disease subtypes and as biomarkers for clinical trials.
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15
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Moshitzky G, Shoham S, Madrer N, Husain AM, Greenberg DS, Yirmiya R, Ben-Shaul Y, Soreq H. Cholinergic Stress Signals Accompany MicroRNA-Associated Stereotypic Behavior and Glutamatergic Neuromodulation in the Prefrontal Cortex. Biomolecules 2020; 10:E848. [PMID: 32503154 PMCID: PMC7355890 DOI: 10.3390/biom10060848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/24/2020] [Accepted: 05/28/2020] [Indexed: 12/13/2022] Open
Abstract
Stereotypic behavior (SB) is common in emotional stress-involved psychiatric disorders and is often attributed to glutamatergic impairments, but the underlying molecular mechanisms are unknown. Given the neuro-modulatory role of acetylcholine, we sought behavioral-transcriptomic links in SB using TgR transgenic mice with impaired cholinergic transmission due to over-expression of the stress-inducible soluble 'readthrough' acetylcholinesterase-R splice variant AChE-R. TgR mice showed impaired organization of behavior, performance errors in a serial maze test, escape-like locomotion, intensified reaction to pilocarpine and reduced rearing in unfamiliar situations. Small-RNA sequencing revealed 36 differentially expressed (DE) microRNAs in TgR mice hippocampi, 8 of which target more than 5 cholinergic transcripts. Moreover, compared to FVB/N mice, TgR prefrontal cortices displayed individually variable changes in over 400 DE mRNA transcripts, primarily acetylcholine and glutamate-related. Furthermore, TgR brains presented c-fos over-expression in motor behavior-regulating brain regions and immune-labeled AChE-R excess in the basal ganglia, limbic brain nuclei and the brain stem, indicating a link with the observed behavioral phenotypes. Our findings demonstrate association of stress-induced SB to previously unknown microRNA-mediated perturbations of cholinergic/glutamatergic networks and underscore new therapeutic strategies for correcting stereotypic behaviors.
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Affiliation(s)
- Gilli Moshitzky
- The Institute of Life Sciences and The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; (G.M.); (N.M.); (A.M.H.); (D.S.G.)
| | - Shai Shoham
- Herzog Medical Center, Givat Shaul, P.O. Box 3900, Jerusalem 9103702, Israel;
| | - Nimrod Madrer
- The Institute of Life Sciences and The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; (G.M.); (N.M.); (A.M.H.); (D.S.G.)
| | - Amir Mouhammed Husain
- The Institute of Life Sciences and The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; (G.M.); (N.M.); (A.M.H.); (D.S.G.)
| | - David S. Greenberg
- The Institute of Life Sciences and The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; (G.M.); (N.M.); (A.M.H.); (D.S.G.)
| | - Raz Yirmiya
- Department of Psychology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
| | - Yoram Ben-Shaul
- Department of Medical Neurobiology, The Institute of Medical Research Israel-Canada, Jerusalem 9112102, Israel;
| | - Hermona Soreq
- The Institute of Life Sciences and The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; (G.M.); (N.M.); (A.M.H.); (D.S.G.)
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16
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Jdila MB, Triki CC, Ghorbel R, Bouchalla W, Ncir SB, Kamoun F, Fakhfakh F. Unusual double mutation in MECP2 and CDKL5 genes in Rett-like syndrome: Correlation with phenotype and genes expression. Clin Chim Acta 2020; 508:287-294. [PMID: 32445745 DOI: 10.1016/j.cca.2020.05.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/12/2020] [Accepted: 05/19/2020] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Rett syndrome (RTT) is a neuro-developmental disorder affecting almost exclusively females and it divided into classical and atypical forms of the disease. RTT-like syndrome was also described and presents an overlapping phenotype of RTT. RTT-like syndrome has been associated with several genes including MECP2 and CDKL5 having common biological pathways and regulatory interactions especially during neural maturation and synaptogenesis. METHODS We report patient with Rett-like syndrome for whom clinical features and their progression guided toward the screening of two candidate genes MECP2 and CDKL5 by sequencing. Severity score was evaluated by "Rett Assessment Rating Scale" (R.A.R.S.). Predictions of pahogenicity and functional effects used several bioinformatic tools and qRT-PCR was conducted to evaluate gene expression. RESULTS Mutational screening revealed two mutations c.1065 C > A (p.S355R) in MECP2 gene and c.616 G > A (p.D206N) mutation in CDKL5 gene in the patient with a high R.A.R.S. Bioinformatic investigations predicted a moderate effect of p.S355R in MECP2 gene but a more pathogenic one of p.D206N mutation in CDKL5. Effect of c.616 G > A mutation on structure and stability of CDKL5 mRNA was confirmed by qRT-PCR. Additionally, analysis of gene expression revealed a drastic effect of CDKL5 mutant on its MeCP2 and Dnmt1 substrates and also on its MYCN regulator. CONCLUSIONS The co-existence of the two mutations in CDKL5 and MECP2 genes could explain the severe phenotype in our patient with RTT-Like and is consistent with the data related to the interactions of CDKL5 with MeCP2 and Dnmt1 proteins.
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Affiliation(s)
- Marwa Ben Jdila
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Tunisia; Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, Sfax University, Tunisia.
| | - Chahnez Charfi Triki
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Tunisia; Child Neurology Department, Hedi Chaker Universitary Hospital of Sfax, Tunisia
| | - Rania Ghorbel
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, Sfax University, Tunisia
| | - Wafa Bouchalla
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Tunisia; Child Neurology Department, Hedi Chaker Universitary Hospital of Sfax, Tunisia
| | - Sihem Ben Ncir
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Tunisia; Child Neurology Department, Hedi Chaker Universitary Hospital of Sfax, Tunisia
| | - Fatma Kamoun
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Tunisia; Child Neurology Department, Hedi Chaker Universitary Hospital of Sfax, Tunisia
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, Sfax University, Tunisia.
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17
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Enikanolaiye A, Ruston J, Zeng R, Taylor C, Schrock M, Buchovecky CM, Shendure J, Acar E, Justice MJ. Suppressor mutations in Mecp2-null mice implicate the DNA damage response in Rett syndrome pathology. Genome Res 2020; 30:540-552. [PMID: 32317254 PMCID: PMC7197480 DOI: 10.1101/gr.258400.119] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 03/20/2020] [Indexed: 12/31/2022]
Abstract
Mutations in X-linked methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome (RTT). To identify functional pathways that could inform therapeutic entry points, we carried out a genetic screen for secondary mutations that improved phenotypes in Mecp2/Y mice after mutagenesis with N-ethyl-N-nitrosourea (ENU). Here, we report the isolation of 106 founder animals that show suppression of Mecp2-null traits from screening 3177 Mecp2/Y genomes. Whole-exome sequencing, genetic crosses, and association analysis identified 22 candidate genes. Additional lesions in these candidate genes or pathway components associate variant alleles with phenotypic improvement in 30 lines. A network analysis shows that 63% of the genes cluster into the functional categories of transcriptional repression, chromatin modification, or DNA repair, delineating a pathway relationship with MECP2. Many mutations lie in genes that modulate synaptic signaling or lipid homeostasis. Mutations in genes that function in the DNA damage response (DDR) also improve phenotypes in Mecp2/Y mice. Association analysis was successful in resolving combinatorial effects of multiple loci. One line, which carries a suppressor mutation in a gene required for cholesterol synthesis, Sqle, carries a second mutation in retinoblastoma binding protein 8, endonuclease (Rbbp8, also known as CtIP), which regulates a DDR choice in double-stranded break (DSB) repair. Cells from Mecp2/Y mice have increased DSBs, so this finding suggests that the balance between homology-directed repair and nonhomologous end joining is important for neuronal cells. In this and other lines, two suppressor mutations confer greater improvement than one alone, suggesting that combination therapies could be effective in RTT.
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Affiliation(s)
- Adebola Enikanolaiye
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - Julie Ruston
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - Rong Zeng
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - Christine Taylor
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - Marijke Schrock
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Christie M Buchovecky
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
- Brotman Baty Institute for Precision Medicine, Seattle, Washington 98195, USA
- Allen Discovery Center for Cell Lineage Tracing, Seattle, Washington 98195, USA
- Howard Hughes Medical Institute, Seattle, Washington 98195, USA
| | - Elif Acar
- The Centre for Phenogenomics, Toronto, Ontario, M5T 3H7, Canada
- Department of Statistics, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Monica J Justice
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- The Centre for Phenogenomics, Toronto, Ontario, M5T 3H7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
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18
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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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Faundez V, Wynne M, Crocker A, Tarquinio D. Molecular Systems Biology of Neurodevelopmental Disorders, Rett Syndrome as an Archetype. Front Integr Neurosci 2019; 13:30. [PMID: 31379529 PMCID: PMC6650571 DOI: 10.3389/fnint.2019.00030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/02/2019] [Indexed: 12/17/2022] Open
Abstract
Neurodevelopmental disorders represent a challenging biological and medical problem due to their genetic and phenotypic complexity. In many cases, we lack the comprehensive understanding of disease mechanisms necessary for targeted therapeutic development. One key component that could improve both mechanistic understanding and clinical trial design is reliable molecular biomarkers. Presently, no objective biological markers exist to evaluate most neurodevelopmental disorders. Here, we discuss how systems biology and "omic" approaches can address the mechanistic and biomarker limitations in these afflictions. We present heuristic principles for testing the potential of systems biology to identify mechanisms and biomarkers of disease in the example of Rett syndrome, a neurodevelopmental disorder caused by a well-defined monogenic defect in methyl-CpG-binding protein 2 (MECP2). We propose that such an approach can not only aid in monitoring clinical disease severity but also provide a measure of target engagement in clinical trials. By deepening our understanding of the "big picture" of systems biology, this approach could even help generate hypotheses for drug development programs, hopefully resulting in new treatments for these devastating conditions.
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Affiliation(s)
- Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, GA, United States
| | - Meghan Wynne
- Department of Cell Biology, Emory University, Atlanta, GA, United States
| | - Amanda Crocker
- Program in Neuroscience, Middlebury College, Middlebury, VT, United States
| | - Daniel Tarquinio
- Rare Neurological Diseases (Private Research Institution), Atlanta, GA, United States
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20
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Mouro FM, Miranda-Lourenço C, Sebastião AM, Diógenes MJ. From Cannabinoids and Neurosteroids to Statins and the Ketogenic Diet: New Therapeutic Avenues in Rett Syndrome? Front Neurosci 2019; 13:680. [PMID: 31333401 PMCID: PMC6614559 DOI: 10.3389/fnins.2019.00680] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/13/2019] [Indexed: 12/21/2022] Open
Abstract
Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused mainly by mutations in the MECP2 gene, being one of the leading causes of mental disability in females. Mutations in the MECP2 gene are responsible for 95% of the diagnosed RTT cases and the mechanisms through which these mutations relate with symptomatology are still elusive. Children with RTT present a period of apparent normal development followed by a rapid regression in speech and behavior and a progressive deterioration of motor abilities. Epilepsy is one of the most common symptoms in RTT, occurring in 60 to 80% of RTT cases, being associated with worsening of other symptoms. At this point, no cure for RTT is available and there is a pressing need for the discovery of new drug candidates to treat its severe symptoms. However, despite being a rare disease, in the last decade research in RTT has grown exponentially. New and exciting evidence has been gathered and the etiopathogenesis of this complex, severe and untreatable disease is slowly being unfolded. Advances in gene editing techniques have prompted cure-oriented research in RTT. Nonetheless, at this point, finding a cure is a distant reality, highlighting the importance of further investigating the basic pathological mechanisms of this disease. In this review, we focus our attention in some of the newest evidence on RTT clinical and preclinical research, evaluating their impact in RTT symptomatology control, and pinpointing possible directions for future research.
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Affiliation(s)
- Francisco Melo Mouro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Catarina Miranda-Lourenço
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Ana Maria Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Maria José Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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Soto D, Olivella M, Grau C, Armstrong J, Alcon C, Gasull X, Santos-Gómez A, Locubiche S, Gómez de Salazar M, García-Díaz R, Gratacòs-Batlle E, Ramos-Vicente D, Chu-Van E, Colsch B, Fernández-Dueñas V, Ciruela F, Bayés À, Sindreu C, López-Sala A, García-Cazorla À, Altafaj X. l-Serine dietary supplementation is associated with clinical improvement of loss-of-function GRIN2B-related pediatric encephalopathy. Sci Signal 2019; 12:12/586/eaaw0936. [DOI: 10.1126/scisignal.aaw0936] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autosomal dominant mutations in GRIN2B are associated with severe encephalopathy, but little is known about the pathophysiological outcomes and any potential therapeutic interventions. Genetic studies have described the association between de novo mutations of genes encoding the subunits of the N-methyl-d-aspartate receptor (NMDAR) and severe neurological conditions. Here, we evaluated a missense mutation in GRIN2B, causing a proline-to-threonine switch (P553T) in the GluN2B subunit of NMDAR, which was found in a 5-year-old patient with Rett-like syndrome with severe encephalopathy. Structural molecular modeling predicted a reduced pore size of the mutant GluN2B-containing NMDARs. Electrophysiological recordings in a HEK-293T cell line expressing the mutated subunit confirmed this prediction and showed an associated reduced glutamate affinity. Moreover, GluN2B(P553T)-expressing primary murine hippocampal neurons showed decreased spine density, concomitant with reduced NMDA-evoked currents and impaired NMDAR-dependent insertion of the AMPA receptor subunit GluA1 at stimulated synapses. Furthermore, the naturally occurring coagonist d-serine restored function to GluN2B(P553T)-containing NMDARs. l-Serine dietary supplementation of the patient was hence initiated, resulting in the increased abundance of d-serine in the plasma and brain. The patient has shown notable improvements in motor and cognitive performance and communication after 11 and 17 months of l-serine dietary supplementation. Our data suggest that l-serine supplementation might ameliorate GRIN2B-related severe encephalopathy and other neurological conditions caused by glutamatergic signaling deficiency.
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22
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Franklin D. P152R Mutation Within MeCP2 Can Cause Loss of DNA-Binding Selectivity. Interdiscip Sci 2019; 11:10-20. [PMID: 30673959 DOI: 10.1007/s12539-019-00316-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 11/29/2022]
Abstract
MeCP2 is a protein highly expressed in the brain that participates in the genetic expression and RNA splicing regulation. MeCP2 binds preferably to methylated DNA and other nuclear corepressors to alter chromatin. MECP2 gene mutations can cause rett syndrome (RTT), a severe neurological disorder that affects around one in ten thousand girls. In this paper, Molecular Dynamics (MD) simulations were performed to scrutinize how the MeCP2 P152R mutation influences the protein binding to DNA. Also, the Umbrella Sampling technique was used to obtain the potential mean forces (PMFs) of both wild-type and mutated MeCP2 Methyl-CpG-binding domain (MBD) binding to both non-methylated and methylated DNA. P152R is a common missense mutation in MBD associated with RTT; however, there are no studies that explain how it causes protein dysfunction. The results from this study hypothesize that P152R mutation leads to MBD binding more strongly to DNA, while selectively decreasing binding affinity to methylated DNA. These provide an explanation for previous not conclusive experimental results regarding the mechanism of how this mutation affects the binding of the protein to DNA, and subsequently its effects on RTT. Furthermore, the results of this research-in-progress can be used as the basis for further investigations into the molecular basis of RTT and to potentially reveal a target for therapy in the future.
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Affiliation(s)
- Dino Franklin
- Faculty of Computing, Federal University of Uberlandia, Uberlândia, Brazil.
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23
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Courchesne E, Pramparo T, Gazestani VH, Lombardo MV, Pierce K, Lewis NE. The ASD Living Biology: from cell proliferation to clinical phenotype. Mol Psychiatry 2019; 24:88-107. [PMID: 29934544 PMCID: PMC6309606 DOI: 10.1038/s41380-018-0056-y] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 02/08/2018] [Accepted: 02/19/2018] [Indexed: 12/17/2022]
Abstract
Autism spectrum disorder (ASD) has captured the attention of scientists, clinicians and the lay public because of its uncertain origins and striking and unexplained clinical heterogeneity. Here we review genetic, genomic, cellular, postmortem, animal model, and cell model evidence that shows ASD begins in the womb. This evidence leads to a new theory that ASD is a multistage, progressive disorder of brain development, spanning nearly all of prenatal life. ASD can begin as early as the 1st and 2nd trimester with disruption of cell proliferation and differentiation. It continues with disruption of neural migration, laminar disorganization, altered neuron maturation and neurite outgrowth, disruption of synaptogenesis and reduced neural network functioning. Among the most commonly reported high-confidence ASD (hcASD) genes, 94% express during prenatal life and affect these fetal processes in neocortex, amygdala, hippocampus, striatum and cerebellum. A majority of hcASD genes are pleiotropic, and affect proliferation/differentiation and/or synapse development. Proliferation and subsequent fetal stages can also be disrupted by maternal immune activation in the 1st trimester. Commonly implicated pathways, PI3K/AKT and RAS/ERK, are also pleiotropic and affect multiple fetal processes from proliferation through synapse and neural functional development. In different ASD individuals, variation in how and when these pleiotropic pathways are dysregulated, will lead to different, even opposing effects, producing prenatal as well as later neural and clinical heterogeneity. Thus, the pathogenesis of ASD is not set at one point in time and does not reside in one process, but rather is a cascade of prenatal pathogenic processes in the vast majority of ASD toddlers. Despite this new knowledge and theory that ASD biology begins in the womb, current research methods have not provided individualized information: What are the fetal processes and early-age molecular and cellular differences that underlie ASD in each individual child? Without such individualized knowledge, rapid advances in biological-based diagnostic, prognostic, and precision medicine treatments cannot occur. Missing, therefore, is what we call ASD Living Biology. This is a conceptual and paradigm shift towards a focus on the abnormal prenatal processes underlying ASD within each living individual. The concept emphasizes the specific need for foundational knowledge of a living child's development from abnormal prenatal beginnings to early clinical stages. The ASD Living Biology paradigm seeks this knowledge by linking genetic and in vitro prenatal molecular, cellular and neural measurements with in vivo post-natal molecular, neural and clinical presentation and progression in each ASD child. We review the first such study, which confirms the multistage fetal nature of ASD and provides the first in vitro fetal-stage explanation for in vivo early brain overgrowth. Within-child ASD Living Biology is a novel research concept we coin here that advocates the integration of in vitro prenatal and in vivo early post-natal information to generate individualized and group-level explanations, clinically useful prognoses, and precision medicine approaches that are truly beneficial for the individual infant and toddler with ASD.
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Affiliation(s)
- Eric Courchesne
- Autism Center of Excellence, Department of Neuroscience, University of California, San Diego, 8110 La Jolla Shores Drive, Suite 201, La Jolla, CA, 92037, USA.
| | - Tiziano Pramparo
- Autism Center of Excellence, Department of Neuroscience, University of California, San Diego, 8110 La Jolla Shores Drive, Suite 201, La Jolla, CA, 92037, USA
| | - Vahid H Gazestani
- Autism Center of Excellence, Department of Neuroscience, University of California, San Diego, 8110 La Jolla Shores Drive, Suite 201, La Jolla, CA, 92037, USA
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Michael V Lombardo
- Department of Psychology, Center for Applied Neuroscience, University of Cyprus, Nicosia, Cyprus
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Karen Pierce
- Autism Center of Excellence, Department of Neuroscience, University of California, San Diego, 8110 La Jolla Shores Drive, Suite 201, La Jolla, CA, 92037, USA
| | - Nathan E Lewis
- Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
- Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
- Novo Nordisk Foundation Center for Biosustainability at University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
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24
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Iourov IY, Vorsanova SG, Yurov YB, Bertrand T. VIII World Rett Syndrome Congress & Symposium of rare diseases, Kazan, Russia. Mol Cytogenet 2018; 11:61. [PMID: 30603047 PMCID: PMC6304760 DOI: 10.1186/s13039-018-0412-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 12/11/2018] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND VIII World Rett Syndrome Congress & Symposium of Rare Diseases was held in Kazan, Russia from 13 to 17 May 2016. Although it has been a while since the event, specific problems highlighted by the contributors to the scientific program have stood the test of time. The Symposium of Rare Diseases has shown that studying Rett syndrome provides clues on molecular and cellular mechanisms for a variety of rare genetic/genomic disorders. Moreover, rare diseases associated with Rett-syndrome-like phenotype or MECP2 mutations/copy number variations have been thoroughly covered by a number of contributors. In this respect, we have found that a review dedicated to the scientific program of the VIII World Rett Syndrome Congress & Symposium of Rare Diseases could be an important addition to current literature. CONCLUSION Taking the opportunity to review the World Rett Syndrome Congress & Symposium of Rare Diseases at Kazan, we have made an attempt to describe a number of achievements and developments in the field of studying Rett syndrome and rare diseases in Russia. Furthermore, chromosomal abnormalities/disorders have been considered in the rare disease context. Such approach to chromosomal abnormalities/disorders has been found to be rather new for an appreciable part of international researchers and health care providers. We do hope that this congress review may be helpful not only for those who are interested in local development of research and management of rare genetic disorders, but also for international researchers and clinical community of rare disease specialists.
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Affiliation(s)
- Ivan Y. Iourov
- Mental Health Research Center, 117152 Moscow, Russia
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Ministry of Health of Russian Federation, 125412 Moscow, Russia
- Department of Medical Genetics, Russian Medical Academy of Continuous Professional Education, Moscow, 125993 Russia
| | - Svetlana G. Vorsanova
- Mental Health Research Center, 117152 Moscow, Russia
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Ministry of Health of Russian Federation, 125412 Moscow, Russia
| | - Yuri B. Yurov
- Mental Health Research Center, 117152 Moscow, Russia
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Ministry of Health of Russian Federation, 125412 Moscow, Russia
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25
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Keogh C, Pini G, Dyer AH, Bigoni S, DiMarco P, Gemo I, Reilly R, Tropea D. Clinical and genetic Rett syndrome variants are defined by stable electrophysiological profiles. BMC Pediatr 2018; 18:333. [PMID: 30340473 PMCID: PMC6195747 DOI: 10.1186/s12887-018-1304-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 10/08/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rett Syndrome (RTT) is a complex neurodevelopmental disorder, frequently associated with epilepsy. Despite increasing recognition of the clinical heterogeneity of RTT and its variants (e.g Classical, Hanefeld and PSV(Preserved Speech Variant)), the link between causative mutations and observed clinical phenotypes remains unclear. Quantitative analysis of electroencephalogram (EEG) recordings may further elucidate important differences between the different clinical and genetic forms of RTT. METHODS Using a large cohort (n = 42) of RTT patients, we analysed the electrophysiological profiles of RTT variants (genetic and clinical) in addition to epilepsy status (no epilepsy/treatment-responsive epilepsy/treatment-resistant epilepsy). The distribution of spectral power and inter-electrode coherence measures were derived from continuous resting-state EEG recordings. RESULTS RTT genetic variants (MeCP2/CDLK5) were characterised by significant differences in network architecture on comparing first principal components of inter-electrode coherence across all frequency bands (p < 0.0001). Greater coherence in occipital and temporal pairs were seen in MeCP2 vs CDLK5 variants, the main drivers in between group differences. Similarly, clinical phenotypes (Classical RTT/Hanefeld/PSV) demonstrated significant differences in network architecture (p < 0.0001). Right tempero-parietal connectivity was found to differ between groups (p = 0.04), with greatest coherence in the Classical RTT phenotype. PSV demonstrated a significant difference in left-sided parieto-occipital coherence (p = 0.026). Whilst overall power decreased over time, there were no difference in asymmetry and inter-electrode coherence profiles over time. There was a significant difference in asymmetry in the overall power spectra between epilepsy groups (p = 0.04) in addition to occipital asymmetry across all frequency bands. Significant differences in network architecture were also seen across epilepsy groups (p = 0.044). CONCLUSIONS Genetic and clinical variants of RTT are characterised by discrete patterns of inter-electrode coherence and network architecture which remain stable over time. Further, hemispheric distribution of spectral power and measures of network dysfunction are associated with epilepsy status and treatment responsiveness. These findings support the role of discrete EEG profiles as non-invasive biomarkers in RTT and its genetic/clinical variants.
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Affiliation(s)
- Conor Keogh
- School of Medicine, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Giorgio Pini
- Tuscany Rett Center, Ospedale Versilia, 55043 Lido di Camaiore, Italy
| | - Adam H. Dyer
- School of Medicine, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Stefania Bigoni
- Medical Genetic Unit, Ferrara University Hospital, Ferrara, Italy
| | - Pietro DiMarco
- Tuscany Rett Center, Ospedale Versilia, 55043 Lido di Camaiore, Italy
| | - Ilaria Gemo
- Tuscany Rett Center, Ospedale Versilia, 55043 Lido di Camaiore, Italy
| | - Richard Reilly
- Trinity Centre for Bioengineering, Trinity College Dublin, Dublin 2, Ireland
| | - Daniela Tropea
- Neuropsychiatric Genetics, Trinity Centre for Health Sciences, St. James’s Hospital, D8 Dublin, Ireland
- Trinity College Institute of Neuroscience (TCIN), Lloyd Building, Trinity College Dublin, Dublin 2, Ireland
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26
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Persistent Lin28 Expression Impairs Neurite Outgrowth and Cognitive Function in the Developing Mouse Neocortex. Mol Neurobiol 2018; 56:3780-3795. [PMID: 30203263 DOI: 10.1007/s12035-018-1297-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/02/2018] [Indexed: 10/28/2022]
Abstract
Many neurodevelopmental disorders feature learning and memory difficulties. Regulation of neurite outgrowth during development is critical for neural plasticity and memory function. Here, we show a novel regulator of neurite outgrowth during cortical neurogenesis, Lin28, which is an RNA-binding protein. Persistent Lin28 upregulation by in utero electroporation at E14.5 resulted in neurite underdevelopment during cortical neurogenesis. We also showed that Lin28-overexpressing cells had an attenuated response to excitatory inputs and altered membrane properties including higher input resistance, slower action potential repolarization, and smaller hyperpolarization-activated cation currents, supporting impaired neuronal functionality in Lin28-electroporated mice. When we ameliorated perturbed Lin28 expression by siRNA, Lin28-induced neurite underdevelopment was rescued with reduction of Lin28-downstream molecules, high mobility group AT-Hook 2, and insulin-like growth factor 1 receptor. Finally, Lin28-electroporated mice showed significant memory deficits as assessed by the Morris water maze test. Taken together, these findings demonstrate a new role and the essential requirement of Lin28 in developmental control of neurite outgrowth, which has an impact on synaptic plasticity and spatial memory. These findings suggest that targeting Lin28 may attenuate intellectual disabilities by correction of impaired dendritic complexity, providing a novel therapeutic candidate for treating neurodevelopmental disorders.
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27
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Interference Resolved: Sorting out Picky Protocadherins in Epilepsy. Epilepsy Curr 2018; 18:189-190. [PMID: 29950947 DOI: 10.5698/1535-7597.18.3.189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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28
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Ali Rodriguez R, Joya C, Hines RM. Common Ribs of Inhibitory Synaptic Dysfunction in the Umbrella of Neurodevelopmental Disorders. Front Mol Neurosci 2018; 11:132. [PMID: 29740280 PMCID: PMC5928253 DOI: 10.3389/fnmol.2018.00132] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/03/2018] [Indexed: 01/06/2023] Open
Abstract
The term neurodevelopmental disorder (NDD) is an umbrella term used to group together a heterogeneous class of disorders characterized by disruption in cognition, emotion, and behavior, early in the developmental timescale. These disorders are heterogeneous, yet they share common behavioral symptomatology as well as overlapping genetic contributors, including proteins involved in the formation, specialization, and function of synaptic connections. Advances may arise from bridging the current knowledge on synapse related factors indicated from both human studies in NDD populations, and in animal models. Mounting evidence has shown a link to inhibitory synapse formation, specialization, and function among Autism, Angelman, Rett and Dravet syndromes. Inhibitory signaling is diverse, with numerous subtypes of inhibitory interneurons, phasic and tonic modes of inhibition, and the molecular and subcellular diversity of GABAA receptors. We discuss common ribs of inhibitory synapse dysfunction in the umbrella of NDD, highlighting alterations in the developmental switch to inhibitory GABA, dysregulation of neuronal activity patterns by parvalbumin-positive interneurons, and impaired tonic inhibition. Increasing our basic understanding of inhibitory synapses, and their role in NDDs is likely to produce significant therapeutic advances in behavioral symptom alleviation for interrelated NDDs.
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Affiliation(s)
- Rachel Ali Rodriguez
- Neuroscience Emphasis, Department of Psychology, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Christina Joya
- Neuroscience Emphasis, Department of Psychology, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Rochelle M Hines
- Neuroscience Emphasis, Department of Psychology, University of Nevada, Las Vegas, Las Vegas, NV, United States
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29
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Mellios N, Feldman DA, Sheridan SD, Ip JP, Kwok S, Amoah SK, Rosen B, Rodriguez BA, Crawford B, Swaminathan R, Chou S, Li Y, Ziats M, Ernst C, Jaenisch R, Haggarty SJ, Sur M. MeCP2-regulated miRNAs control early human neurogenesis through differential effects on ERK and AKT signaling. Mol Psychiatry 2018; 23:1051-1065. [PMID: 28439102 PMCID: PMC5815944 DOI: 10.1038/mp.2017.86] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 02/12/2017] [Accepted: 02/28/2017] [Indexed: 12/15/2022]
Abstract
Rett syndrome (RTT) is an X-linked, neurodevelopmental disorder caused primarily by mutations in the methyl-CpG-binding protein 2 (MECP2) gene, which encodes a multifunctional epigenetic regulator with known links to a wide spectrum of neuropsychiatric disorders. Although postnatal functions of MeCP2 have been thoroughly investigated, its role in prenatal brain development remains poorly understood. Given the well-established importance of microRNAs (miRNAs) in neurogenesis, we employed isogenic human RTT patient-derived induced pluripotent stem cell (iPSC) and MeCP2 short hairpin RNA knockdown approaches to identify novel MeCP2-regulated miRNAs enriched during early human neuronal development. Focusing on the most dysregulated miRNAs, we found miR-199 and miR-214 to be increased during early brain development and to differentially regulate extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase and protein kinase B (PKB/AKT) signaling. In parallel, we characterized the effects on human neurogenesis and neuronal differentiation brought about by MeCP2 deficiency using both monolayer and three-dimensional (cerebral organoid) patient-derived and MeCP2-deficient neuronal culture models. Inhibiting miR-199 or miR-214 expression in iPSC-derived neural progenitors deficient in MeCP2 restored AKT and ERK activation, respectively, and ameliorated the observed alterations in neuronal differentiation. Moreover, overexpression of miR-199 or miR-214 in the wild-type mouse embryonic brains was sufficient to disturb neurogenesis and neuronal migration in a similar manner to Mecp2 knockdown. Taken together, our data support a novel miRNA-mediated pathway downstream of MeCP2 that influences neurogenesis via interactions with central molecular hubs linked to autism spectrum disorders.
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Affiliation(s)
- Nikolaos Mellios
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, 87131,Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139,Correspondence to and
| | - Danielle A. Feldman
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Steven D. Sheridan
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139,Chemical Neurobiology Laboratory, Center for Human Genetic Research, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Jacque P.K. Ip
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Showming Kwok
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Stephen K. Amoah
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, 87131
| | - Bess Rosen
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Brian A. Rodriguez
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, 87131
| | - Benjamin Crawford
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Radha Swaminathan
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, 87131
| | - Stephanie Chou
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Yun Li
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Mark Ziats
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892
| | - Carl Ernst
- Department of Psychiatry, McGill University, Montreal, QC Canada
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Stephen J. Haggarty
- Chemical Neurobiology Laboratory, Center for Human Genetic Research, Departments of Neurology & Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139,Correspondence to and
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Nguyen AT, Mattiassi S, Loeblein M, Chin E, Ma D, Coquet P, Viasnoff V, Teo EHT, Goh EL, Yim EKF. Human Rett-derived neuronal progenitor cells in 3D graphene scaffold as an in vitro platform to study the effect of electrical stimulation on neuronal differentiation. ACTA ACUST UNITED AC 2018; 13:034111. [PMID: 29442069 DOI: 10.1088/1748-605x/aaaf2b] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Studies of electrical stimulation therapies for the treatment of neurological disorders, such as deep brain stimulation, have almost exclusively been performed using animal-models. However, because animal-models can only approximate human brain disorders, these studies should be supplemented with an in vitro human cell-culture based model to substantiate the results of animal-based studies and further investigate therapeutic benefit in humans. This study presents a novel approach to analyze the effect of electrical stimulation on the neurogenesis of patient-induced pluripotent stem cell (iPSC) derived neural progenitor cell (NPC) lines, in vitro using a 3D graphene scaffold system. The iPSC-derived hNPCs used to demonstrate the system were collected from patients with Rett syndrome, a debilitating neurodevelopmental disorder. The graphene scaffold readily supported both the wild-type and Rett NPCs. Electrical stimulation parameters were optimized to accommodate both wild-type and Rett cells. Increased cell maturation and improvements in cell morphology of the Rett cells was observed after electrical stimulation. The results of the pilot study of electrical stimulation to enhance Rett NPCs neurogenesis were promising and support further investigation of the therapy. Overall, this system provides a valuable tool to study electrical stimulation as a potential therapy for neurological disorders using patient-specific cells.
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Affiliation(s)
- Anh Tuan Nguyen
- Mechanobiology Institute Singapore, National University of Singapore, T-Lab, #05-01, 5A Engineering Drive 1, 117411, Singapore. Neuroscience Academic Clinical Programme, Duke-NUS Medical School, 20 College Road, 169856, Singapore
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31
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Soto D, Olivella M, Grau C, Armstrong J, Alcon C, Gasull X, Gómez de Salazar M, Gratacòs-Batlle E, Ramos-Vicente D, Fernández-Dueñas V, Ciruela F, Bayés À, Sindreu C, López-Sala A, García-Cazorla À, Altafaj X. Rett-like Severe Encephalopathy Caused by a De Novo GRIN2B Mutation Is Attenuated by D-serine Dietary Supplement. Biol Psychiatry 2018; 83:160-172. [PMID: 28734458 DOI: 10.1016/j.biopsych.2017.05.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 04/26/2017] [Accepted: 05/17/2017] [Indexed: 01/13/2023]
Abstract
BACKGROUND N-Methyl-D-aspartate receptors (NMDARs) play pivotal roles in synaptic development, plasticity, neural survival, and cognition. Despite recent reports describing the genetic association between de novo mutations of NMDAR subunits and severe psychiatric diseases, little is known about their pathogenic mechanisms and potential therapeutic interventions. Here we report a case study of a 4-year-old Rett-like patient with severe encephalopathy carrying a missense de novo mutation in GRIN2B(p.P553T) coding for the GluN2B subunit of NMDAR. METHODS We generated a dynamic molecular model of mutant GluN2B-containing NMDARs. We expressed the mutation in cell lines and primary cultures, and we evaluated the putative morphological, electrophysiological, and synaptic plasticity alterations. Finally, we evaluated D-serine administration as a therapeutic strategy and translated it to the clinical practice. RESULTS Structural molecular modeling predicted a reduced pore size of mutant NMDARs. Electrophysiological recordings confirmed this prediction and also showed gating alterations, a reduced glutamate affinity associated with a strong decrease of NMDA-evoked currents. Moreover, GluN2B(P553T)-expressing neurons showed decreased spine density, concomitant with reduced NMDA-evoked currents and impaired NMDAR-dependent insertion of GluA1 at stimulated synapses. Notably, the naturally occurring coagonist D-serine was able to attenuate hypofunction of GluN2B(p.P553T)-containing NMDARs. Hence, D-serine dietary supplementation was initiated. Importantly, the patient has shown remarkable motor, cognitive, and communication improvements after 17 months of D-serine dietary supplementation. CONCLUSIONS Our data suggest that hypofunctional NMDARs containing GluN2B(p.P553T) can contribute to Rett-like encephalopathy and that their potentiation by D-serine treatment may underlie the associated clinical improvement.
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Affiliation(s)
- David Soto
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Biomedicine, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain
| | - Mireia Olivella
- Bioinfomatics and Medical Statistics Group, University of Vic-Central University of Catalonia, Barcelona, Spain
| | - Cristina Grau
- Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Judith Armstrong
- Genetics and Molecular Medicine Service, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Clara Alcon
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Clinical Foundations, University of Barcelona, Barcelona, Spain
| | - Xavier Gasull
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Biomedicine, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain
| | - Macarena Gómez de Salazar
- Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Esther Gratacòs-Batlle
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Biomedicine, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain
| | - David Ramos-Vicente
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain; Autonomous University of Barcelona, Bellaterra, Barcelona, Spain
| | - Víctor Fernández-Dueñas
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain; Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Francisco Ciruela
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain; Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain; Autonomous University of Barcelona, Bellaterra, Barcelona, Spain
| | - Carlos Sindreu
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Clinical Foundations, University of Barcelona, Barcelona, Spain
| | - Anna López-Sala
- Department of Neurology, Neurometabolic Unit, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Àngels García-Cazorla
- Genetics and Molecular Medicine Service, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain; Department of Neurology, Neurometabolic Unit, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Xavier Altafaj
- Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain.
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Xu X, Pozzo-Miller L. EEA1 restores homeostatic synaptic plasticity in hippocampal neurons from Rett syndrome mice. J Physiol 2017. [PMID: 28621434 DOI: 10.1113/jp274450] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Rett syndrome is a neurodevelopmental disorder caused by loss-of-function mutations in MECP2, the gene encoding the transcriptional regulator methyl-CpG-binding protein 2 (MeCP2). Mecp2 deletion in mice results in an imbalance of excitation and inhibition in hippocampal neurons, which affects 'Hebbian' synaptic plasticity. We show that Mecp2-deficient neurons also lack homeostatic synaptic plasticity, likely due to reduced levels of EEA1, a protein involved in AMPA receptor endocytosis. Expression of EEA1 restored homeostatic synaptic plasticity in Mecp2-deficient neurons, providing novel targets of intervention in Rett syndrome. ABSTRACT Rett syndrome is a neurodevelopmental disorder caused by loss-of-function mutations in MECP2, the gene encoding the transcriptional regulator methyl-CpG-binding protein 2 (MeCP2). Deletion of Mecp2 in mice results in an imbalance of synaptic excitation and inhibition in hippocampal pyramidal neurons, which affects 'Hebbian' long-term synaptic plasticity. Since the excitatory-inhibitory balance is maintained by homeostatic mechanisms, we examined the role of MeCP2 in homeostatic synaptic plasticity (HSP) at excitatory synapses. Negative feedback HSP, also known as synaptic scaling, maintains the global synaptic strength of individual neurons in response to sustained alterations in neuronal activity. Hippocampal neurons from Mecp2 knockout (KO) mice do not show the characteristic homeostatic scaling up of the amplitude of miniature excitatory postsynaptic currents (mEPSCs) and of synaptic levels of the GluA1 subunit of AMPA-type glutamate receptors after 48 h silencing with the Na+ channel blocker tetrodotoxin. This deficit in HSP is bidirectional because Mecp2 KO neurons also failed to scale down mEPSC amplitudes and GluA1 synaptic levels after 48 h blockade of type A GABA receptor (GABAA R)-mediated inhibition with bicuculline. Consistent with the role of synaptic trafficking of AMPA-type of glutamate receptors in HSP, Mecp2 KO neurons have lower levels of early endosome antigen 1 (EEA1), a protein involved in AMPA-type glutamate receptor endocytosis. In addition, expression of EEA1 in Mecp2 KO neurons reduced mEPSC amplitudes to wild-type levels, and restored synaptic scaling down of mEPSC amplitudes after 48 h blockade of GABAA R-mediated inhibition with bicuculline. The identification of a molecular deficit in HSP in Mecp2 KO neurons provides potentially novel targets of intervention for improving hippocampal function in Rett syndrome individuals.
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Affiliation(s)
- Xin Xu
- Department of Neurobiology, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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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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Veeraragavan S, Wan YW, Connolly DR, Hamilton SM, Ward CS, Soriano S, Pitcher MR, McGraw CM, Huang SG, Green JR, Yuva LA, Liang AJ, Neul JL, Yasui DH, LaSalle JM, Liu Z, Paylor R, Samaco RC. Loss of MeCP2 in the rat models regression, impaired sociability and transcriptional deficits of Rett syndrome. Hum Mol Genet 2016; 25:3284-3302. [PMID: 27365498 PMCID: PMC5179927 DOI: 10.1093/hmg/ddw178] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/18/2016] [Accepted: 06/08/2016] [Indexed: 01/31/2023] Open
Abstract
Mouse models of the transcriptional modulator Methyl-CpG-Binding Protein 2 (MeCP2) have advanced our understanding of Rett syndrome (RTT). RTT is a 'prototypical' neurodevelopmental disorder with many clinical features overlapping with other intellectual and developmental disabilities (IDD). Therapeutic interventions for RTT may therefore have broader applications. However, the reliance on the laboratory mouse to identify viable therapies for the human condition may present challenges in translating findings from the bench to the clinic. In addition, the need to identify outcome measures in well-chosen animal models is critical for preclinical trials. Here, we report that a novel Mecp2 rat model displays high face validity for modelling psychomotor regression of a learned skill, a deficit that has not been shown in Mecp2 mice. Juvenile play, a behavioural feature that is uniquely present in rats and not mice, is also impaired in female Mecp2 rats. Finally, we demonstrate that evaluating the molecular consequences of the loss of MeCP2 in both mouse and rat may result in higher predictive validity with respect to transcriptional changes in the human RTT brain. These data underscore the similarities and differences caused by the loss of MeCP2 among divergent rodent species which may have important implications for the treatment of individuals with disease-causing MECP2 mutations. Taken together, these findings demonstrate that the Mecp2 rat model is a complementary tool with unique features for the study of RTT and highlight the potential benefit of cross-species analyses in identifying potential disease-relevant preclinical outcome measures.
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Affiliation(s)
- Surabi Veeraragavan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Ying-Wooi Wan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Daniel R Connolly
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Christopher S Ward
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sirena Soriano
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Meagan R Pitcher
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Christopher M McGraw
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sharon G Huang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Lisa A Yuva
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Agnes J Liang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jeffrey L Neul
- Department of Pediatrics, Section of Neurology
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Dag H Yasui
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Janine M LaSalle
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Zhandong Liu
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Rodney C Samaco
- Department of Molecular and Human Genetics
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
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Reichow B, George-Puskar A, Lutz T, Smith IC, Volkmar FR. Brief report: systematic review of Rett syndrome in males. J Autism Dev Disord 2016; 45:3377-83. [PMID: 26254891 DOI: 10.1007/s10803-015-2519-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Rett syndrome (RTT) is a neurogenetic disorder in which a period of typical development is followed by loss of previously acquired skills. Once thought to occur exclusively in females, increasing numbers of male cases of RTT have been reported. This systematic review included 36 articles describing 57 cases of RTT in males. Mutations of the MECP2 gene were present in 56 % of cases, and 68 % of cases reported other genetic abnormalities. This is the first review of published reports of RTT in male patients.
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Affiliation(s)
- Brian Reichow
- AJ Pappanikou Center for Excellence in Developmental Disabilities, University of Connecticut Health Center, Farmington, CT, USA.
- University of Florida, 1345Q Norman Hall, PO Box 117050, Gainesville, FL, 32661-7050, USA.
| | | | - Tara Lutz
- University of Connecticut, Storrs, CT, USA
| | - Isaac C Smith
- AJ Pappanikou Center for Excellence in Developmental Disabilities, University of Connecticut Health Center, Farmington, CT, USA
- Yale Child Study Center, New Haven, CT, USA
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Impairments in dendrite morphogenesis as etiology for neurodevelopmental disorders and implications for therapeutic treatments. Neurosci Biobehav Rev 2016; 68:946-978. [PMID: 27143622 DOI: 10.1016/j.neubiorev.2016.04.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 04/13/2016] [Accepted: 04/13/2016] [Indexed: 02/08/2023]
Abstract
Dendrite morphology is pivotal for neural circuitry functioning. While the causative relationship between small-scale dendrite morphological abnormalities (shape, density of dendritic spines) and neurodevelopmental disorders is well established, such relationship remains elusive for larger-scale dendrite morphological impairments (size, shape, branching pattern of dendritic trees). Here, we summarize published data on dendrite morphological irregularities in human patients and animal models for neurodevelopmental disorders, with focus on autism and schizophrenia. We next discuss high-risk genes for these disorders and their role in dendrite morphogenesis. We finally overview recent developments in therapeutic attempts and we discuss how they relate to dendrite morphology. We find that both autism and schizophrenia are accompanied by dendritic arbor morphological irregularities, and that majority of their high-risk genes regulate dendrite morphogenesis. Thus, we present a compelling argument that, along with smaller-scale morphological impairments in dendrites (spines and synapse), irregularities in larger-scale dendrite morphology (arbor shape, size) may be an important part of neurodevelopmental disorders' etiology. We suggest that this should not be ignored when developing future therapeutic treatments.
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Zhang ZN, Freitas BC, Qian H, Lux J, Acab A, Trujillo CA, Herai RH, Nguyen Huu VA, Wen JH, Joshi-Barr S, Karpiak JV, Engler AJ, Fu XD, Muotri AR, Almutairi A. Layered hydrogels accelerate iPSC-derived neuronal maturation and reveal migration defects caused by MeCP2 dysfunction. Proc Natl Acad Sci U S A 2016; 113:3185-90. [PMID: 26944080 PMCID: PMC4812712 DOI: 10.1073/pnas.1521255113] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Probing a wide range of cellular phenotypes in neurodevelopmental disorders using patient-derived neural progenitor cells (NPCs) can be facilitated by 3D assays, as 2D systems cannot entirely recapitulate the arrangement of cells in the brain. Here, we developed a previously unidentified 3D migration and differentiation assay in layered hydrogels to examine how these processes are affected in neurodevelopmental disorders, such as Rett syndrome. Our soft 3D system mimics the brain environment and accelerates maturation of neurons from human induced pluripotent stem cell (iPSC)-derived NPCs, yielding electrophysiologically active neurons within just 3 wk. Using this platform, we revealed a genotype-specific effect of methyl-CpG-binding protein-2 (MeCP2) dysfunction on iPSC-derived neuronal migration and maturation (reduced neurite outgrowth and fewer synapses) in 3D layered hydrogels. Thus, this 3D system expands the range of neural phenotypes that can be studied in vitro to include those influenced by physical and mechanical stimuli or requiring specific arrangements of multiple cell types.
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Affiliation(s)
- Zhen-Ning Zhang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Beatriz C Freitas
- Department of Pediatrics, Rady Children's Hospital-San Diego, San Diego, CA 92123; Stem Cell Program, Department of Cellular & Molecular Medicine, University of California, San Diego School of Medicine, Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Hao Qian
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0651; Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093-0651
| | - Jacques Lux
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Allan Acab
- Department of Pediatrics, Rady Children's Hospital-San Diego, San Diego, CA 92123; Stem Cell Program, Department of Cellular & Molecular Medicine, University of California, San Diego School of Medicine, Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Cleber A Trujillo
- Department of Pediatrics, Rady Children's Hospital-San Diego, San Diego, CA 92123; Stem Cell Program, Department of Cellular & Molecular Medicine, University of California, San Diego School of Medicine, Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Roberto H Herai
- Department of Pediatrics, Rady Children's Hospital-San Diego, San Diego, CA 92123; Stem Cell Program, Department of Cellular & Molecular Medicine, University of California, San Diego School of Medicine, Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Viet Anh Nguyen Huu
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Jessica H Wen
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Shivanjali Joshi-Barr
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Jerome V Karpiak
- Department of Pediatrics, Rady Children's Hospital-San Diego, San Diego, CA 92123; Stem Cell Program, Department of Cellular & Molecular Medicine, University of California, San Diego School of Medicine, Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Adam J Engler
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0651; Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093-0651
| | - Alysson R Muotri
- Department of Pediatrics, Rady Children's Hospital-San Diego, San Diego, CA 92123; Stem Cell Program, Department of Cellular & Molecular Medicine, University of California, San Diego School of Medicine, Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037;
| | - Adah Almutairi
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093;
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Tarquinio DC, Hou W, Neul JL, Kaufmann WE, Glaze DG, Motil KJ, Skinner SA, Lee HS, Percy AK. The Changing Face of Survival in Rett Syndrome and MECP2-Related Disorders. Pediatr Neurol 2015; 53:402-11. [PMID: 26278631 PMCID: PMC4609589 DOI: 10.1016/j.pediatrneurol.2015.06.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 06/04/2015] [Accepted: 06/05/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Survival in Rett syndrome remains unclear. Although early estimates were grim, more recent data suggest that survival into adulthood is typical. We aimed to define survival in Rett syndrome more clearly and identify risk factors for early death. METHODS Participants with clinical Rett Syndrome or methyl-CpG-binding protein 2 mutations without clinical RTT were recruited through the Rett Syndrome Natural History study from 2006 to 2015. Clinical details were collected, and survival was determined using the Kaplan-Meier estimator. Risk factors were assessed using Cox proportional hazards models. RESULTS Among 1189 valid participants, 51 died (range 3.9-66.6 years) during the 9-year follow-up period. Those who died included 36 (3.9%) classic Rett syndrome females, 5 (5.9%) atypical severe Rett syndrome females, 1 (2.4%) non-Rett syndrome female, the single atypical severe male, 6 (30%) non-Rett syndrome males, and 2 (7.1%) methyl-CpG-binding protein 2 duplication syndrome males. All atypical mild Rett syndrome females, methyl-CpG-binding protein 2 duplication syndrome females, and the single classic Rett syndrome male remain alive. Most deaths were due to cardiorespiratory issues. Only one died from severe malnutrition, scoliosis, and extreme frailty. Survival for classic and atypical Rett syndrome was greater than 70% at 45 years. Overall severity and several modifiable risk factors, including ambulation, weight, and seizures, were associated with mortality in classic Rett syndrome. CONCLUSIONS Survival into the fifth decade is typical in Rett syndrome, and death due to extreme frailty has become rare. Although the leading cause of death remains cardiorespiratory compromise, many risk factors for early death are modifiable. Intense therapeutic interventions could further improve the prognosis for individuals with Rett syndrome.
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Affiliation(s)
| | - Wei Hou
- Stony Brook University Medical Center, Stony Brook, NY
| | - Jeffrey L. Neul
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | | | - Daniel G. Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | | | | | - Hye-Seung Lee
- Pediatrics Epidemiology Center, University of South Florida, Tampa, FL
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Kucukkal TG, Yang Y, Uvarov O, Cao W, Alexov E. Impact of Rett Syndrome Mutations on MeCP2 MBD Stability. Biochemistry 2015; 54:6357-68. [PMID: 26418480 PMCID: PMC9871983 DOI: 10.1021/acs.biochem.5b00790] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Rett syndrome causing missense mutations in the methyl-CpG-binding domain (MBD) of methyl CpG-binding protein 2 (MeCP2) were investigated both in silico and in vitro to reveal their effect on protein stability. It is demonstrated that the vast majority of frequently occurring mutations in the human population indeed alter the MBD folding free energy by a fraction of a kcal/mol up to more than 1 kcal/mol. While the absolute magnitude of the change of the free energy is small, the effect on the MBD functionality may be substantial since the folding free energy of MBD is about 2 kcal/mol only. Thus, it is emphasized that the effect of mutations on protein integrity should be evaluated with respect to the wild-type folding free energy but not with the absolute value of the folding free energy change. Furthermore, it was observed that the magnitude of the effect is correlated neither with the burial of the mutation sites nor with the basic amino acid physicochemical property change. Mutations that strongly perturb the immediate structural features were found to have little effect on folding free energy, while very conservative mutations resulted in large changes of the MBD stability. This observation was attributed to the protein's ability to structurally relax and reorganize to reduce the effect of mutation. Comparison between in silico and in vitro results indicated that some Web servers perform relatively well, while the free energy perturbation approach frequently overpredicts the magnitude of the free energy change especially when a charged amino acid is involved.
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Affiliation(s)
- Tugba G Kucukkal
- Department of Physics, Clemson University, 118 Kinard Laboratory, Clemson, SC 29634, USA
| | - Ye Yang
- Department of Genetics and Biochemistry, Clemson University, 049 Life Sciences Facility, Clemson, SC 29634, USA
| | - Olga Uvarov
- Department of Genetics and Biochemistry, Clemson University, 049 Life Sciences Facility, Clemson, SC 29634, USA
| | - Weiguo Cao
- Department of Genetics and Biochemistry, Clemson University, 049 Life Sciences Facility, Clemson, SC 29634, USA,Weiguo Cao: , Tel: 864-656-4176; Fax: 864-656-6879, Alexov: , Tel: 864-908-4796, Fax: 864-656-0805
| | - Emil Alexov
- Department of Physics, Clemson University, 118 Kinard Laboratory, Clemson, SC 29634, USA,Weiguo Cao: , Tel: 864-656-4176; Fax: 864-656-6879, Alexov: , Tel: 864-908-4796, Fax: 864-656-0805
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Ammanuel S, Chan WC, Adler DA, Lakshamanan BM, Gupta SS, Ewen JB, Johnston MV, Marcus CL, Naidu S, Kadam SD. Heightened Delta Power during Slow-Wave-Sleep in Patients with Rett Syndrome Associated with Poor Sleep Efficiency. PLoS One 2015; 10:e0138113. [PMID: 26444000 PMCID: PMC4596813 DOI: 10.1371/journal.pone.0138113] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 08/25/2015] [Indexed: 12/31/2022] Open
Abstract
Sleep problems are commonly reported in Rett syndrome (RTT); however the electroencephalographic (EEG) biomarkers underlying sleep dysfunction are poorly understood. The aim of this study was to analyze the temporal evolution of quantitative EEG (qEEG) biomarkers in overnight EEGs recorded from girls (2-9 yrs. old) diagnosed with RTT using a non-traditional automated protocol. In this study, EEG spectral analysis identified high delta power cycles representing slow wave sleep (SWS) in 8-9h overnight sleep EEGs from the frontal, central and occipital leads (AP axis), comparing age-matched girls with and without RTT. Automated algorithms quantitated the area under the curve (AUC) within identified SWS cycles for each spectral frequency wave form. Both age-matched RTT and control EEGs showed similar increasing trends for recorded delta wave power in the EEG leads along the antero-posterior (AP). RTT EEGs had significantly fewer numbers of SWS sleep cycles; therefore, the overall time spent in SWS was also significantly lower in RTT. In contrast, the AUC for delta power within each SWS cycle was significantly heightened in RTT and remained heightened over consecutive cycles unlike control EEGs that showed an overnight decrement of delta power in consecutive cycles. Gamma wave power associated with these SWS cycles was similar to controls. However, the negative correlation of gamma power with age (r = -.59; p<0.01) detected in controls (2-5 yrs. vs. 6-9 yrs.) was lost in RTT. Poor % SWS (i.e., time spent in SWS overnight) in RTT was also driven by the younger age-group. Incidence of seizures in RTT was associated with significantly lower number of SWS cycles. Therefore, qEEG biomarkers of SWS in RTT evolved temporally and correlated significantly with clinical severity.
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Affiliation(s)
- Simon Ammanuel
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, Whiting School of Engineering,Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Wesley C. Chan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, Whiting School of Engineering,Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Daniel A. Adler
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, Whiting School of Engineering,Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Balaji M. Lakshamanan
- Department of Neurology and Developmental Medicine, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
| | - Siddharth S. Gupta
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Joshua B. Ewen
- Department of Neurology and Developmental Medicine, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Michael V. Johnston
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Carole L. Marcus
- Sleep Center, The Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Sakkubai Naidu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shilpa D. Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Kloth AD, Badura A, Li A, Cherskov A, Connolly SG, Giovannucci A, Bangash MA, Grasselli G, Peñagarikano O, Piochon C, Tsai PT, Geschwind DH, Hansel C, Sahin M, Takumi T, Worley PF, Wang SSH. Cerebellar associative sensory learning defects in five mouse autism models. eLife 2015; 4:e06085. [PMID: 26158416 PMCID: PMC4512177 DOI: 10.7554/elife.06085] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 07/03/2015] [Indexed: 12/17/2022] Open
Abstract
Sensory integration difficulties have been reported in autism, but their underlying brain-circuit mechanisms are underexplored. Using five autism-related mouse models, Shank3+/ΔC, Mecp2(R308/Y), Cntnap2-/-, L7-Tsc1 (L7/Pcp2(Cre)::Tsc1(flox/+)), and patDp(15q11-13)/+, we report specific perturbations in delay eyeblink conditioning, a form of associative sensory learning requiring cerebellar plasticity. By distinguishing perturbations in the probability and characteristics of learned responses, we found that probability was reduced in Cntnap2-/-, patDp(15q11-13)/+, and L7/Pcp2(Cre)::Tsc1(flox/+), which are associated with Purkinje-cell/deep-nuclear gene expression, along with Shank3+/ΔC. Amplitudes were smaller in L7/Pcp2(Cre)::Tsc1(flox/+) as well as Shank3+/ΔC and Mecp2(R308/Y), which are associated with granule cell pathway expression. Shank3+/ΔC and Mecp2(R308/Y) also showed aberrant response timing and reduced Purkinje-cell dendritic spine density. Overall, our observations are potentially accounted for by defects in instructed learning in the olivocerebellar loop and response representation in the granule cell pathway. Our findings indicate that defects in associative temporal binding of sensory events are widespread in autism mouse models.
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Affiliation(s)
- Alexander D Kloth
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Aleksandra Badura
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Amy Li
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Adriana Cherskov
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Sara G Connolly
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - Andrea Giovannucci
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, United States
| | - M Ali Bangash
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Giorgio Grasselli
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Olga Peñagarikano
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Claire Piochon
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Peter T Tsai
- The F.M. Kirby Neurobiology Center, Department of Neurology, Children's Hospital Boston, Harvard Medical School, Boston, United States
| | - Daniel H Geschwind
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Christian Hansel
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Mustafa Sahin
- The F.M. Kirby Neurobiology Center, Department of Neurology, Children's Hospital Boston, Harvard Medical School, Boston, United States
| | | | - Paul F Worley
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Samuel S-H Wang
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, United States
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Hara M, Ohba C, Yamashita Y, Saitsu H, Matsumoto N, Matsuishi T. De novoSHANK3mutation causes Rett syndrome-like phenotype in a female patient. Am J Med Genet A 2015; 167:1593-6. [DOI: 10.1002/ajmg.a.36775] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 08/13/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Munetsugu Hara
- Department of Neonatology; Medical Center for Maternal and Child Health; St. Mary's Hospital Kurume Fukuoka Japan
| | - Chihiro Ohba
- Department of Human Genetics; Graduate School of Medicine; Yokohama City University; Kanazawa-ku Yokohama Japan
| | - Yushiro Yamashita
- Departments of Pediatrics and Child Health; Kurume University School of Medicine; Kurume Fukuoka Japan
| | - Hirotomo Saitsu
- Department of Human Genetics; Graduate School of Medicine; Yokohama City University; Kanazawa-ku Yokohama Japan
| | - Naomichi Matsumoto
- Department of Human Genetics; Graduate School of Medicine; Yokohama City University; Kanazawa-ku Yokohama Japan
| | - Toyojiro Matsuishi
- Departments of Pediatrics and Child Health; Kurume University School of Medicine; Kurume Fukuoka Japan
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Phillips M, Pozzo-Miller L. Dendritic spine dysgenesis in autism related disorders. Neurosci Lett 2015; 601:30-40. [PMID: 25578949 DOI: 10.1016/j.neulet.2015.01.011] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/31/2014] [Accepted: 01/04/2015] [Indexed: 01/22/2023]
Abstract
The activity-dependent structural and functional plasticity of dendritic spines has led to the long-standing belief that these neuronal compartments are the subcellular sites of learning and memory. Of relevance to human health, central neurons in several neuropsychiatric illnesses, including autism related disorders, have atypical numbers and morphologies of dendritic spines. These so-called dendritic spine dysgeneses found in individuals with autism related disorders are consistently replicated in experimental mouse models. Dendritic spine dysgenesis reflects the underlying synaptopathology that drives clinically relevant behavioral deficits in experimental mouse models, providing a platform for testing new therapeutic approaches. By examining molecular signaling pathways, synaptic deficits, and spine dysgenesis in experimental mouse models of autism related disorders we find strong evidence for mTOR to be a critical point of convergence and promising therapeutic target.
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Affiliation(s)
- Mary Phillips
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Structural, Dynamical, and Energetical Consequences of Rett Syndrome Mutation R133C in MeCP2. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:746157. [PMID: 26064184 PMCID: PMC4431600 DOI: 10.1155/2015/746157] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/11/2015] [Indexed: 12/25/2022]
Abstract
Rett Syndrome (RTT) is a progressive neurodevelopmental disease affecting females. RTT is caused by mutations in the MECP2 gene and various amino acid substitutions have been identified clinically in different domains of the multifunctional MeCP2 protein encoded by this gene. The R133C variant in the methylated-CpG-binding domain (MBD) of MeCP2 is the second most common disease-causing mutation in the MBD. Comparative molecular dynamics simulations of R133C mutant and wild-type MBD have been performed to understand the impact of the mutation on structure, dynamics, and interactions of the protein and subsequently understand the disease mechanism. Two salt bridges within the protein and two critical hydrogen bonds between the protein and DNA are lost upon the R133C mutation. The mutation was found to weaken the interaction with DNA and also cause loss of helicity within the 141-144 region. The structural, dynamical, and energetical consequences of R133C mutation were investigated in detail at the atomic resolution. Several important implications of this have been shown regarding protein stability and hydration dynamics as well as its interaction with DNA. The results are in agreement with previous experimental studies and further provide atomic level understanding of the molecular origin of RTT associated with R133C variant.
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Ma LY, Wu C, Jin Y, Gao M, Li GH, Turner D, Shen JX, Zhang SJ, Narayanan V, Jentarra G, Wu J. Electrophysiological phenotypes of MeCP2 A140V mutant mouse model. CNS Neurosci Ther 2014; 20:420-8. [PMID: 24750778 DOI: 10.1111/cns.12229] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 12/27/2013] [Accepted: 01/03/2014] [Indexed: 11/27/2022] Open
Abstract
AIMS MeCP2 gene mutations are associated with Rett syndrome and X-linked mental retardation (XLMR), diseases characterized by abnormal brain development and function. Recently, we created a novel MeCP2 A140V mutation mouse model that exhibited abnormalities of cell packing density and dendritic branching consistent with that seen in Rett syndrome patients as well as other MeCP2 mutant mouse models. Therefore, we hypothesized that some deficits of neuronal and synaptic functions might also be present in the A140V mutant model. METHODS Here, we tested our hypothesis in hippocampal slices using electrophysiological recordings. RESULTS We found that in young A140V mutant mice (3- to 4-week-old), hippocampal CA1 pyramidal neurons exhibited more positive resting membrane potential, increased action potential (AP) firing frequency induced by injection of depolarizing current, wider AP duration, and smaller after hyperpolarization potential compared to neurons prepared from age-matched wild-type mice, suggesting a neuronal hyperexcitation. At the synaptic level, A140V mutant neurons exhibited a reduced frequency of spontaneous IPSCs (inhibitory postsynaptic potentials) and an enhanced probability of evoked glutamate release, both suggesting neuronal hyperexcitation. However, hippocampal CA1 long-term potentiation was not significantly different between A140V and WT mice. In adult mice (11- to 13-month-old), in addition to neuronal hyperexcitation, we also found significant deficits of both short-term and long-term potentiation of CA3-CA1 synapses in A140V mice compared to WT mice. CONCLUSIONS These results clearly illustrate the age-dependent abnormalities of neuronal and synaptic function in the MeCP2 A140V mutant mouse model, which provides new insights into the understanding of the pathogenesis of Rett syndrome.
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Abstract
Mutations in Methyl-CpG-Binding protein 2 (MECP2) are commonly associated with the neurodevelopmental disorder Rett syndrome (RTT). However, some people with RTT do not have mutations in MECP2, and interestingly there have been people identified with MECP2 mutations that do not have the clinical features of RTT. In this report we present four people with neurodevelopmental abnormalities and clear RTT-disease causing MECP2 mutation but lacking the characteristic clinical features of RTT. One patient's symptoms suggest an extension of the known spectrum of MECP2 associated phenotypes to include global developmental delay with obsessive compulsive disorder and attention deficit hyperactivity disorder. These results reemphasize that RTT should remain a clinical diagnosis, based on the recent consensus criteria.
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Szczesna K, de la Caridad O, Petazzi P, Soler M, Roa L, Saez MA, Fourcade S, Pujol A, Artuch-Iriberri R, Molero-Luis M, Vidal A, Huertas D, Esteller M. Improvement of the Rett syndrome phenotype in a MeCP2 mouse model upon treatment with levodopa and a dopa-decarboxylase inhibitor. Neuropsychopharmacology 2014; 39:2846-56. [PMID: 24917201 PMCID: PMC4200495 DOI: 10.1038/npp.2014.136] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/28/2014] [Accepted: 06/02/2014] [Indexed: 12/12/2022]
Abstract
Rett Syndrome is a neurodevelopmental autism spectrum disorder caused by mutations in the gene coding for methyl CpG-binding protein (MeCP2). The disease is characterized by abnormal motor, respiratory, cognitive impairment, and autistic-like behaviors. No effective treatment of the disorder is available. Mecp2 knockout mice have a range of physiological and neurological abnormalities that resemble the human syndrome and can be used as a model to interrogate new therapies. Herein, we show that the combined administration of Levodopa and a Dopa-decarboxylase inhibitor in RTT mouse models is well tolerated, diminishes RTT-associated symptoms, and increases life span. The amelioration of RTT symptomatology is particularly significant in those features controlled by the dopaminergic pathway in the nigrostratium, such as mobility, tremor, and breathing. Most important, the improvement of the RTT phenotype upon use of the combined treatment is reflected at the cellular level by the development of neuronal dendritic growth. However, much work is required to extend the duration of the benefit of the described preclinical treatment.
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Affiliation(s)
- Karolina Szczesna
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Olga de la Caridad
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Paolo Petazzi
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Marta Soler
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Laura Roa
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Mauricio A Saez
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Stéphane Fourcade
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Institute of Neuropathology, University of Barcelona, Barcelona, Spain,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Institute of Neuropathology, University of Barcelona, Barcelona, Spain,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain,Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Rafael Artuch-Iriberri
- Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain,Neurometabolic Unit, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Marta Molero-Luis
- Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain,Neurometabolic Unit, Hospital Sant Joan de Déu, Barcelona, Spain
| | - August Vidal
- Department of Pathology, Bellvitge University Hospital, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Dori Huertas
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 3rd Floor, Hospital Duran i Reynals, Avenue Gran Via 199-203, L'Hospitalet, Barcelona 08908, Catalonia, Spain, Tel: +34 932607253, Fax: +34 932607140, E-mail: or
| | - Manel Esteller
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain,Department of Physiological Sciences II, School of Medicine, University of Barcelona, Barcelona, Spain,Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 3rd Floor, Hospital Duran i Reynals, Avenue Gran Via 199-203, L'Hospitalet, Barcelona 08908, Catalonia, Spain, Tel: +34 932607253, Fax: +34 932607140, E-mail: or
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48
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Ma Q, Xiong F, Zhang L. Gestational hypoxia and epigenetic programming of brain development disorders. Drug Discov Today 2014; 19:1883-96. [PMID: 25256780 DOI: 10.1016/j.drudis.2014.09.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/23/2014] [Accepted: 09/16/2014] [Indexed: 01/04/2023]
Abstract
Adverse environmental conditions faced by an individual early during its life, such as gestational hypoxia, can have a profound influence on the risk of diseases, such as neurological disorders, in later life. Clinical and preclinical studies suggest that epigenetic programming of gene expression patterns in response to maternal stress have a crucial role in the fetal origins of neurological diseases. Herein, we summarize recent studies regarding the role of epigenetic mechanisms in the developmental programming of neurological diseases in offspring, primarily focusing on DNA methylation/demethylation and miRNAs. Such information could increase our understanding of the fetal origins of adult diseases and help develop effective prevention and intervention against neurological diseases.
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Affiliation(s)
- Qingyi Ma
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
| | - Fuxia Xiong
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
| | - Lubo Zhang
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
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Xu X, Miller EC, Pozzo-Miller L. Dendritic spine dysgenesis in Rett syndrome. Front Neuroanat 2014; 8:97. [PMID: 25309341 PMCID: PMC4159975 DOI: 10.3389/fnana.2014.00097] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 08/25/2014] [Indexed: 11/13/2022] Open
Abstract
Spines are small cytoplasmic extensions of dendrites that form the postsynaptic compartment of the majority of excitatory synapses in the mammalian brain. Alterations in the numerical density, size, and shape of dendritic spines have been correlated with neuronal dysfunction in several neurological and neurodevelopmental disorders associated with intellectual disability, including Rett syndrome (RTT). RTT is a progressive neurodevelopmental disorder associated with intellectual disability that is caused by loss of function mutations in the transcriptional regulator methyl CpG-binding protein 2 (MECP2). Here, we review the evidence demonstrating that principal neurons in RTT individuals and Mecp2-based experimental models exhibit alterations in the number and morphology of dendritic spines. We also discuss the exciting possibility that signaling pathways downstream of brain-derived neurotrophic factor (BDNF), which is transcriptionally regulated by MeCP2, offer promising therapeutic options for modulating dendritic spine development and plasticity in RTT and other MECP2-associated neurodevelopmental disorders.
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Affiliation(s)
- Xin Xu
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
| | - Eric C Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
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50
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Bellini E, Pavesi G, Barbiero I, Bergo A, Chandola C, Nawaz MS, Rusconi L, Stefanelli G, Strollo M, Valente MM, Kilstrup-Nielsen C, Landsberger N. MeCP2 post-translational modifications: a mechanism to control its involvement in synaptic plasticity and homeostasis? Front Cell Neurosci 2014; 8:236. [PMID: 25165434 PMCID: PMC4131190 DOI: 10.3389/fncel.2014.00236] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/27/2014] [Indexed: 12/02/2022] Open
Abstract
Although Rett syndrome (RTT) represents one of the most frequent forms of severe intellectual disability in females worldwide, we still have an inadequate knowledge of the many roles played by MeCP2 (whose mutations are responsible for most cases of RTT) and their relevance for RTT pathobiology. Several studies support a role of MeCP2 in the regulation of synaptic plasticity and homeostasis. At the molecular level, MeCP2 is described as a repressor capable of inhibiting gene transcription through chromatin compaction. Indeed, it interacts with several chromatin remodeling factors, such as HDAC-containing complexes and ATRX. Other studies have inferred that MeCP2 functions also as an activator; a role in regulating mRNA splicing and in modulating protein synthesis has also been proposed. Further, MeCP2 avidly binds both 5-methyl- and 5-hydroxymethyl-cytosine. Recent evidence suggests that it is the highly disorganized structure of MeCP2, together with its post-translational modifications (PTMs) that generate and regulate this functional versatility. Indeed, several reports have demonstrated that differential phosphorylation of MeCP2 is a key mechanism by which the methyl binding protein modulates its affinity for its partners, gene expression and cellular adaptations to stimuli and neuronal plasticity. As logic consequence, generation of phospho-defective Mecp2 knock-in mice has permitted associating alterations in neuronal morphology, circuit formation, and mouse behavioral phenotypes with specific phosphorylation events. MeCP2 undergoes various other PTMs, including acetylation, ubiquitination and sumoylation, whose functional roles remain largely unexplored. These results, together with the genome-wide distribution of MeCP2 and its capability to substitute histone H1, recall the complex regulation of histones and suggest the relevance of quickly gaining a deeper comprehension of MeCP2 PTMs, the respective writers and readers and the consequent functional outcomes.
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Affiliation(s)
- Elisa Bellini
- Division of Neuroscience, San Raffaele Rett Research Center, San Raffaele Scientific Institute Milan, Italy
| | - Giulio Pavesi
- Department of Biosciences, University of Milan Milan, Italy
| | - Isabella Barbiero
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Anna Bergo
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Chetan Chandola
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Mohammad S Nawaz
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Laura Rusconi
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Gilda Stefanelli
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Marta Strollo
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Maria M Valente
- Division of Neuroscience, San Raffaele Rett Research Center, San Raffaele Scientific Institute Milan, Italy
| | - Charlotte Kilstrup-Nielsen
- Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
| | - Nicoletta Landsberger
- Division of Neuroscience, San Raffaele Rett Research Center, San Raffaele Scientific Institute Milan, Italy ; Section of Biomedical Research, Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Theoretic and Applied Sciences, University of Insubria Busto Arsizio, Italy
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