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Copping NA, McTighe SM, Fink KD, Silverman JL. Emerging Gene and Small Molecule Therapies for the Neurodevelopmental Disorder Angelman Syndrome. Neurotherapeutics 2021; 18:1535-1547. [PMID: 34528170 PMCID: PMC8608975 DOI: 10.1007/s13311-021-01082-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2021] [Indexed: 02/07/2023] Open
Abstract
Angelman syndrome (AS) is a rare (~1:15,000) neurodevelopmental disorder characterized by severe developmental delay and intellectual disability, impaired communication skills, and a high prevalence of seizures, sleep disturbances, ataxia, motor deficits, and microcephaly. AS is caused by loss-of-function of the maternally inherited UBE3A gene. UBE3A is located on chromosome 15q11-13 and is biallelically expressed throughout the body but only maternally expressed in the brain due to an RNA antisense transcript that silences the paternal copy. There is currently no cure for AS, but advancements in small molecule drugs and gene therapies offer a promising approach for the treatment of the disorder. Here, we review AS and how loss-of-function of the maternal UBE3A contributes to the disorder. We also discuss the strengths and limitations of current animal models of AS. Furthermore, we examine potential small molecule drug and gene therapies for the treatment of AS and associated challenges faced by the therapeutic design. Finally, gene therapy offers the opportunity for precision medicine in AS and advancements in the treatment of this disorder can serve as a foundation for other single-gene neurodevelopmental disorders.
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Affiliation(s)
- Nycole A Copping
- School of Medicine, Department of Psychiatry and Behavioral Sciences, MIND Institute, University of California, Research II Building 96, 4625 2nd Avenue, Suite 1001B, Davis, Sacramento, CA, 95817, USA
- Stem Cell Program and Gene Therapy Center, Department of Neurology, MIND Institute, University of California, Davis, Sacramento, CA, USA
| | | | - Kyle D Fink
- Stem Cell Program and Gene Therapy Center, Department of Neurology, MIND Institute, University of California, Davis, Sacramento, CA, USA
| | - Jill L Silverman
- School of Medicine, Department of Psychiatry and Behavioral Sciences, MIND Institute, University of California, Research II Building 96, 4625 2nd Avenue, Suite 1001B, Davis, Sacramento, CA, 95817, USA.
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Berg EL, Pride MC, Petkova SP, Lee RD, Copping NA, Shen Y, Adhikari A, Fenton TA, Pedersen LR, Noakes LS, Nieman BJ, Lerch JP, Harris S, Born HA, Peters MM, Deng P, Cameron DL, Fink KD, Beitnere U, O'Geen H, Anderson AE, Dindot SV, Nash KR, Weeber EJ, Wöhr M, Ellegood J, Segal DJ, Silverman JL. Translational outcomes in a full gene deletion of ubiquitin protein ligase E3A rat model of Angelman syndrome. Transl Psychiatry 2020; 10:39. [PMID: 32066685 PMCID: PMC7026078 DOI: 10.1038/s41398-020-0720-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/17/2019] [Accepted: 01/02/2020] [Indexed: 12/17/2022] Open
Abstract
Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by developmental delay, impaired communication, motor deficits and ataxia, intellectual disabilities, microcephaly, and seizures. The genetic cause of AS is the loss of expression of UBE3A (ubiquitin protein ligase E6-AP) in the brain, typically due to a deletion of the maternal 15q11-q13 region. Previous studies have been performed using a mouse model with a deletion of a single exon of Ube3a. Since three splice variants of Ube3a exist, this has led to a lack of consistent reports and the theory that perhaps not all mouse studies were assessing the effects of an absence of all functional UBE3A. Herein, we report the generation and functional characterization of a novel model of Angelman syndrome by deleting the entire Ube3a gene in the rat. We validated that this resulted in the first comprehensive gene deletion rodent model. Ultrasonic vocalizations from newborn Ube3am-/p+ were reduced in the maternal inherited deletion group with no observable change in the Ube3am+/p- paternal transmission cohort. We also discovered Ube3am-/p+ exhibited delayed reflex development, motor deficits in rearing and fine motor skills, aberrant social communication, and impaired touchscreen learning and memory in young adults. These behavioral deficits were large in effect size and easily apparent in the larger rodent species. Low social communication was detected using a playback task that is unique to rats. Structural imaging illustrated decreased brain volume in Ube3am-/p+ and a variety of intriguing neuroanatomical phenotypes while Ube3am+/p- did not exhibit altered neuroanatomy. Our report identifies, for the first time, unique AS relevant functional phenotypes and anatomical markers as preclinical outcomes to test various strategies for gene and molecular therapies in AS.
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Affiliation(s)
- E L Berg
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - M C Pride
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - S P Petkova
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - R D Lee
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - N A Copping
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Y Shen
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - A Adhikari
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - T A Fenton
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - L R Pedersen
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - L S Noakes
- Mouse Imaging Centre, Toronto Centre for Phenogenomics, The Hospital for Sick Children, Toronto, ON, Canada
| | - B J Nieman
- Mouse Imaging Centre, Toronto Centre for Phenogenomics, The Hospital for Sick Children, Toronto, ON, Canada
| | - J P Lerch
- Wellcome Centre for Integrative Neuroimaging, The University of Oxford, Oxford, UK
| | - S Harris
- Department of Pediatrics and Neurology, Baylor College of Medicine, Houston, TX, USA
| | - H A Born
- Department of Pediatrics and Neurology, Baylor College of Medicine, Houston, TX, USA
| | - M M Peters
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - P Deng
- Stem Cell Program, Institute for Regenerative Cures, and Department of Neurology, University of California Davis School of Medicine, Sacramento, CA, USA
| | - D L Cameron
- Stem Cell Program, Institute for Regenerative Cures, and Department of Neurology, University of California Davis School of Medicine, Sacramento, CA, USA
| | - K D Fink
- Stem Cell Program, Institute for Regenerative Cures, and Department of Neurology, University of California Davis School of Medicine, Sacramento, CA, USA
| | - U Beitnere
- MIND Institute, Genome Center, and Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - H O'Geen
- MIND Institute, Genome Center, and Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - A E Anderson
- Department of Pediatrics and Neurology, Baylor College of Medicine, Houston, TX, USA
| | - S V Dindot
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - K R Nash
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - E J Weeber
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - M Wöhr
- Behavioral Neuroscience, Experimental and Biological Psychology, Philipps-University of Marburg, Marburg, Germany
| | - J Ellegood
- Mouse Imaging Centre, Toronto Centre for Phenogenomics, The Hospital for Sick Children, Toronto, ON, Canada
| | - D J Segal
- MIND Institute, Genome Center, and Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - J L Silverman
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA.
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Bretz CL, Frey WD, Teruyama R, Kim J. Allele and dosage specificity of the Peg3 imprinted domain. PLoS One 2018; 13:e0197069. [PMID: 29734399 PMCID: PMC5937776 DOI: 10.1371/journal.pone.0197069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 04/25/2018] [Indexed: 11/19/2022] Open
Abstract
The biological impetus for gene dosage and allele specificity of mammalian imprinted genes is not fully understood. To address this, we generated and analyzed four sets of mice from a single breeding scheme with varying allelic expression and gene dosage of the Peg3 domain. The mutants with abrogation of the two paternally expressed genes, Peg3 and Usp29, showed a significant decrease in growth rates for both males and females, while the mutants with biallelic expression of Peg3 and Usp29 resulted in an increased growth rate of female mice only. The mutant cohort with biallelic expression of Peg3 and Usp29 tended to have greater numbers of pups compared to the other genotypes. The mutants with switched active alleles displayed overall similar phenotypes to the wild type, but did show some differences in gene expression, suggesting potential non-redundant roles contributed by the maternal and paternal alleles. Overall, this study demonstrates a novel in vivo approach to investigate the allele and dosage specificity of mammalian imprinted domains.
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Affiliation(s)
- Corey L. Bretz
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
| | - Wesley D. Frey
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
| | - Ryoichi Teruyama
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
| | - Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States of America
- * E-mail:
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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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Sadikovic B, Fernandes P, Zhang VW, Ward PA, Miloslavskaya I, Rhead W, Rosenbaum R, Gin R, Roa B, Fang P. Mutation Update for UBE3A variants in Angelman syndrome. Hum Mutat 2015; 35:1407-17. [PMID: 25212744 DOI: 10.1002/humu.22687] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 08/25/2014] [Indexed: 11/07/2022]
Abstract
Angelman syndrome is a neurodevelopmental disorder caused by a deficiency of the imprinted and maternally expressed UBE3A gene. Although de novo genetic and epigenetic imprinting defects of UBE3A genomic locus account for majority of Angelman diagnoses, approximately 10% of individuals affected with Angelman syndrome are a result of UBE3A loss-of-function mutations occurring on the expressed maternal chromosome. The variants described in this manuscript represent the analysis of 2,515 patients referred for UBE3A gene sequencing at our institution, along with a comprehensive review of the UBE3A mutation literature. Of these, 267 (10.62%) patients had a report issued for detection of a UBE3A gene nucleotide variant, which in many cases involved family studies resulting in reclassification of variants of unknown clinical significance (VUS). Overall, 111 (4.41%) probands had a nucleotide change classified as pathogenic or strongly favored to be pathogenic, 29 (1.15%) had a VUS, and 126 (5.0%) had a nucleotide change classified as benign or strongly favored to be benign. All variants and their clinical interpretations are submitted to NCBI ClinVar, a freely accessible human variation and phenotype database.
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Affiliation(s)
- Bekim Sadikovic
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
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Abstract
Two major environmental developments have occurred in mammalian evolution which have impacted on the genetic and epigenetic regulation of brain development. The first of these was viviparity and development of the placenta which placed a considerable burden of time and energy investment on the matriline, and which resulted in essential hypothalamic modifications. Maternal feeding, maternal care, parturition, milk letdown and the suspension of fertility and sexual behaviour are all determined by the maternal hypothalamus and have evolved to meet foetal needs under the influence of placental hormones. Viviparity itself provided a new environmental variable for selection pressures to operate via the co-existence over three generations of matrilineal genomes (mother, developing offspring and developing oocytes) in one individual. Also of importance for the matriline has been the evolution of epigenetic marks (imprint control regions) which are heritable and undergo reprogramming primarily in the oocyte to regulate imprinted gene expression according to parent of origin. Imprinting of autosomal genes has played a significant role in mammalian evolutionary development, particularly that of the hypothalamus and placenta. Indeed, many imprinted genes that are co-expressed in the placenta and hypothalamus play an important role in the co-adapted functioning of these organs. Thus the action and interaction of two genomes (maternal and foetal) have provided a template for transgenerational selection pressures to operate in shaping the mothering capabilities of each subsequent generation. The advanced aspects of neocortical brain evolution in primates have emancipated much of behaviour from the determining effects of hormonal action. Thus in large brain primates, most of the sexual behaviour is not reproductive hormone dependent and maternal care can and does occur outside the context of pregnancy and parturition. The neocortex has evolved to be adaptable and while the adapted changes are not inherited, the epigenetic predisposing processes can be. This provides each generation with the same ability to generate new adaptations while retaining a "cultural" predisposition to retain others. A significant evolutionary contribution to this epigenetic dimension has again been the matriline. The extensive neocortical development which takes place post-natally does so in an environment which is predominantly that of the caring guidance of the mother. Evidence for the epigenetic regulation of neocortical development is best illustrated by the GABA-ergic neurons and their long tangential migratory pathway from the ganglionic eminence, in contrast to the radial migration of principle neurons. GABA-ergic neurons play an integral role both in the developmental formation of canonical localised circuits and in synchronising widespread functional activity by the regulation of network oscillations. Such synchronisation enables distributed regions of the neocortex to coordinate firing. GABA-ergic dysfunction contributes to a broad spectrum of neurological and psychiatric disorders which can differ even across identical monozygotic twins. Moreover, major treatments for schizophrenia over the past 40 years have included the drugs lithium and valproate, both of which we now know are histone deacetylases. It is rarely the heritable dysfunctioning of these epigenetic mechanisms that is at fault, but the timing, duration and place where they are deployed. The timing and complexity in the development of the neocortex makes this region of the brain more vulnerable to perturbations.
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Affiliation(s)
- E B Keverne
- Sub-Department of Animal Behaviour, University of Cambridge, Madingley, Cambridge CB23 8AA, UK.
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