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Fritzsch B. Evolution and development of extraocular motor neurons, nerves and muscles in vertebrates. Ann Anat 2024; 253:152225. [PMID: 38346566 DOI: 10.1016/j.aanat.2024.152225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/16/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024]
Abstract
The purpose of this review is to analyze the origin of ocular motor neurons, define the pattern of innervation of nerve fibers that project to the extraocular eye muscles (EOMs), describe congenital disorders that alter the development of ocular motor neurons, and provide an overview of vestibular pathway inputs to ocular motor nuclei. Six eye muscles are innervated by axons of three ocular motor neurons, the oculomotor (CNIII), trochlear (CNIV), and abducens (CNVI) neurons. Ocular motor neurons (CNIII) originate in the midbrain and innervate the ipsilateral orbit, except for the superior rectus and the levator palpebrae, which are contralaterally innervated. Trochlear motor neurons (CNIV) originate at the midbrain-hindbrain junction and innervate the contralateral superior oblique muscle. Abducens motor neurons (CNVI) originate variously in the hindbrain of rhombomeres r4-6 that innervate the posterior (or lateral) rectus muscle and innervate the retractor bulbi. Genes allow a distinction between special somatic (CNIII, IV) and somatic (CNVI) ocular motor neurons. Development of ocular motor neurons and their axonal projections to the EOMs may be derailed by various genetic causes, resulting in the congenital cranial dysinnervation disorders. The ocular motor neurons innervate EOMs while the vestibular nuclei connect with the midbrain-brainstem motor neurons.
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Affiliation(s)
- Bernd Fritzsch
- Department of Neurological Sciences, University of Nebraska Medical Center, NE, USA.
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Wang M, Liu J, Pang H, Bu J. Special clinical features with a novel mutation site of CHN1 gene in a Chinese family with Duane retraction syndrome. Strabismus 2024; 32:23-29. [PMID: 38509018 DOI: 10.1080/09273972.2023.2299470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
PURPOSE This study is to describe the special clinical and genotypic features of a Chinese family with variant types of Duane retraction syndrome and to present our experience on managing these cases. METHODS Four individuals from one family were reviewed by ophthalmologic examinations, in which two affected and two unaffected individuals were revealed. MRI scans were performed on the two patients. Relevant gene mutations were screened by the next-generation sequencing technology and confirmed by Sanger sequencing technology. RESULTS The six-year-old proband presented with special clinical features of severe horizontal gaze dysfunction, exotropia and mild scoliosis. His mother showed significantly limited binocular abductions, with retraction of eyeballs in adduction. From MRI scans, abducens nerves were not observed in both patients and the oculomotor nerve was slightly thin in the proband. The proband and his mother shared the same CHN1 gene mutation site (c. 62A>G; p.Y21C). Strabismus surgery was performed on the proband to correct the primary gaze exotropia.(NM_001822: exon3 or NM_001025201: exon4: c. 62A>G; p.Y21C). CONCLUSIONS A novel CHN1 gene mutation was revealed from a Chinese family with Duane retraction syndrome. Remarkably, the proband and his mother presented different clinical features of ocular motility disorder. Strabismus correction surgery and amblyopia training helped to improve the appearance and visual function of the proband.
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Affiliation(s)
- Minshu Wang
- Department of Ophthalmology, Peking University Third Hospital, Beijing
- Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing
| | - Jing Liu
- Department of Ophthalmology, Peking University Third Hospital, Beijing
- Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing
| | - Honglei Pang
- Department of Ophthalmology, Peking University Third Hospital, Beijing
- Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing
| | - Juan Bu
- Department of Ophthalmology, Peking University Third Hospital, Beijing
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3
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Manso-Bazús C, Spataro N, Gabau E, Beltrán-Salazar VP, Trujillo-Quintero JP, Capdevila N, Brunet-Vega A, Baena N, Jeyaprakash AA, Martinez-Glez V, Ruiz A. Case report: Identification of a novel variant p.Gly215Arg in the CHN1 gene causing Moebius syndrome. Front Genet 2024; 15:1291063. [PMID: 38356699 PMCID: PMC10865368 DOI: 10.3389/fgene.2024.1291063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 01/15/2024] [Indexed: 02/16/2024] Open
Abstract
Background: Moebius Syndrome (MBS) is a rare congenital neurological disorder characterized by paralysis of facial nerves, impairment of ocular abduction and other variable abnormalities. MBS has been attributed to both environmental and genetic factors as potential causes. Until now only two genes, PLXND1 and REV3L have been identified to cause MBS. Results: We present a 9-year-old male clinically diagnosed with MBS, presenting facial palsy, altered ocular mobility, microglossia, dental anomalies and congenital torticollis. Radiologically, he lacks both abducens nerves and shows altered symmetry of both facial and vestibulocochlear nerves. Whole-exome sequence identified a de novo missense variant c.643G>A; p.Gly215Arg in CHN1, encoding the α2-chimaerin protein. The p.Gly215Arg variant is located in the C1 domain of CHN1 where other pathogenic gain of function variants have been reported. Bioinformatic analysis and molecular structural modelling predict a deleterious effect of the missense variant on the protein function. Conclusion: Our findings support that pathogenic variants in the CHN1 gene may be responsible for different cranial congenital dysinnervation syndromes, including Moebius and Duane retraction syndromes. We propose to include CHN1 in the genetic diagnoses of MBS.
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Affiliation(s)
- Carmen Manso-Bazús
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Nino Spataro
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Elisabeth Gabau
- Paediatric Service, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Viviana P. Beltrán-Salazar
- Radiology Service, Parc Taulí Hospital Universitari, Institut d’investigación i innovació Parc Taulí (I3PT-CERCA), Universitat Autónoma de Barcelona, Sabadell, Spain
| | - Juan Pablo Trujillo-Quintero
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Nuria Capdevila
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Anna Brunet-Vega
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Neus Baena
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - A Arockia Jeyaprakash
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
- The Gene Centre and Department of Biochemistry, Ludwig Maximilian Universität, München, Germany
| | - Victor Martinez-Glez
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Anna Ruiz
- Center for Genomic Medicine, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT-CERCA), Universitat Autònoma de Barcelona, Sabadell, Spain
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Zhang R, Jia H, Chang Q, Zhang Z, Peng C, Ma Q, Liang Y, Yang S, Jiao Y. Two novel CHN1 variants identified in Duane retraction syndrome pedigrees disrupt development of ocular motor nerves in zebrafish. J Hum Genet 2024; 69:33-39. [PMID: 37853116 DOI: 10.1038/s10038-023-01201-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/20/2023]
Abstract
Duane retraction syndrome (DRS) is a rare congenital eye movement disorder causing by the dysplasia of abducens nerve, and has highly variable phenotype. MRI can reveal the endophenotype of DRS. Most DRS cases are sporadical and isolated, while some are familial or accompanied by other ocular disorders and systemic congenital abnormalities. CHN1 was the most common causative gene for familial DRS. Until now, 13 missense variants of CHN1 have been reported. In this study, we enrolled two unrelated pedigrees with DRS. Detailed clinical examinations, MRI, and the whole exome sequencing (WES) were performed to reveal their clinical and genetic characteristics. Patients from pedigree-1 presented with isolated DRS, and a novel heterozygous variant c.650 A > G, p. His217Arg was identified in CHN1 gene. Patients from pedigree-2 presented with classic DRS and abnormalities in auricle morphology, and the pedigree segregated another novel heterozygous CHN1 variant c.637 T > C, p. Phe213Leu. A variety of bioinformatics software predicted that the two variants had deleterious or disease-causing effects. After injecting of two mutant CHN1 mRNAs into zebrafish embryos, the dysplasia of ocular motor nerves (OMN) was observed. Our present findings expanded the phenotypic and genotypic spectrum of CHN1 related DRS, as well as provided new insights into the role of CHN1 in OMN development. Genetic testing is strongly recommended for patients with a DRS family history or accompanying systemic congenital abnormalities.
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Affiliation(s)
- Ranran Zhang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Ophthalmology and Visual Science Key Lab, 100730, Beijing, China
| | - Hongyan Jia
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Ophthalmology and Visual Science Key Lab, 100730, Beijing, China
| | - Qinglin Chang
- Department of Radiology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
| | - Zongrui Zhang
- Department of Radiology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
| | - Chuzhi Peng
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Ophthalmology and Visual Science Key Lab, 100730, Beijing, China
| | - Qian Ma
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Ophthalmology and Visual Science Key Lab, 100730, Beijing, China
| | - Yi Liang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Ophthalmology and Visual Science Key Lab, 100730, Beijing, China
| | - Shuyan Yang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, 100020, Beijing, China.
| | - Yonghong Jiao
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China.
- Beijing Ophthalmology and Visual Science Key Lab, 100730, Beijing, China.
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Lee AS, Ayers LJ, Kosicki M, Chan WM, Fozo LN, Pratt BM, Collins TE, Zhao B, Rose MF, Sanchis-Juan A, Fu JM, Wong I, Zhao X, Tenney AP, Lee C, Laricchia KM, Barry BJ, Bradford VR, Lek M, MacArthur DG, Lee EA, Talkowski ME, Brand H, Pennacchio LA, Engle EC. A cell type-aware framework for nominating non-coding variants in Mendelian regulatory disorders. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.12.22.23300468. [PMID: 38234731 PMCID: PMC10793524 DOI: 10.1101/2023.12.22.23300468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Unsolved Mendelian cases often lack obvious pathogenic coding variants, suggesting potential non-coding etiologies. Here, we present a single cell multi-omic framework integrating embryonic mouse chromatin accessibility, histone modification, and gene expression assays to discover cranial motor neuron (cMN) cis-regulatory elements and subsequently nominate candidate non-coding variants in the congenital cranial dysinnervation disorders (CCDDs), a set of Mendelian disorders altering cMN development. We generated single cell epigenomic profiles for ~86,000 cMNs and related cell types, identifying ~250,000 accessible regulatory elements with cognate gene predictions for ~145,000 putative enhancers. Seventy-five percent of elements (44 of 59) validated in an in vivo transgenic reporter assay, demonstrating that single cell accessibility is a strong predictor of enhancer activity. Applying our cMN atlas to 899 whole genome sequences from 270 genetically unsolved CCDD pedigrees, we achieved significant reduction in our variant search space and nominated candidate variants predicted to regulate known CCDD disease genes MAFB, PHOX2A, CHN1, and EBF3 - as well as new candidates in recurrently mutated enhancers through peak- and gene-centric allelic aggregation. This work provides novel non-coding variant discoveries of relevance to CCDDs and a generalizable framework for nominating non-coding variants of potentially high functional impact in other Mendelian disorders.
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Affiliation(s)
- Arthur S. Lee
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Lauren J. Ayers
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
| | - Michael Kosicki
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Wai-Man Chan
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
- Howard Hughes Medical Institute, Chevy Chase, MD
| | - Lydia N. Fozo
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
| | - Brandon M. Pratt
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
| | - Thomas E. Collins
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
| | - Boxun Zhao
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA
| | - Matthew F. Rose
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Department of Pathology, Boston Children's Hospital, Boston, MA
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
- Medical Genetics Training Program, Harvard Medical School, Boston, MA
| | - Alba Sanchis-Juan
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA
| | - Jack M. Fu
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Isaac Wong
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA
| | - Xuefang Zhao
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Alan P. Tenney
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Cassia Lee
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
- Harvard College, Cambridge, MA
| | - Kristen M. Laricchia
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Brenda J. Barry
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
- Howard Hughes Medical Institute, Chevy Chase, MD
| | - Victoria R. Bradford
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
| | - Monkol Lek
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Daniel G. MacArthur
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Centre for Population Genomics, Garvan Institute of Medical Research and UNSW Sydney, Sydney, NSW, Australia
- Centre for Population Genomics, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Eunjung Alice Lee
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA
- Department of Genetics, Harvard Medical School, Boston, MA
| | - Michael E. Talkowski
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Harrison Brand
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA
| | - Len A. Pennacchio
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Elizabeth C. Engle
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA
- Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
- Howard Hughes Medical Institute, Chevy Chase, MD
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA
- Medical Genetics Training Program, Harvard Medical School, Boston, MA
- Department of Ophthalmology, Boston Children’s Hospital and Harvard Medical School, Boston, MA
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6
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Wang R, Gao Y, Wu S, Cai X, Yu T, Wang L. Research hotspots and trends of oculomotor nerve palsy from 2001 to 2021 based on web of science: A bibliometric analysis. Front Neurol 2023; 14:1112070. [PMID: 36908629 PMCID: PMC9992801 DOI: 10.3389/fneur.2023.1112070] [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: 11/30/2022] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Background Oculomotor nerve palsy (ONP) is a clinically occurring neurological disorder. Due to the complex anatomy and long travel distances of the oculomotor nerve, the causes of ONP vary and manifest in various ways. With continued interest in this area, it has become necessary to conduct a bibliometric study in ONP. This work aims to synthesize and visually identify current research themes and future trends in ONP through a literature-based analysis. Method Articles and reviews on ONP published from 2002 to 2021 were derived from the Web of Science Core Collection (WoSCC) database. We generated visual images and performed quantitative and qualitative analysis through an online bibliometric tool, Citespace and VOSviewer software. Results A total of 1,205 published articles were included in this analysis. The annual number of this area's publications is showing an overall upward trend, with the number of citations increasing every year, reaching 2,698 by 2021. The United States (367) and Japan (116) dominated the list with the most numerous articles published. The University of California Los Angeles in the USA is the institution that published the highest number of articles (47). Engle EC (23) and the JOURNAL OF NEUROSURGERY (46) are the most influential authors and journals in this field. The co-occurrence network analysis divided the keywords into five main research themes, which mainly include clinical manifestations of ONP, aneurysms, cerebral neurological symptoms, diseases with ONP as a complication, and other neurological disorders. Conclusion This study is the first comprehensive and systematic bibliometric analysis of the current state of global ONP research over the past 20 years. We organized current hotspots and expected trends and provided key information for exploring potential research frontiers in ONP.
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Affiliation(s)
- Runze Wang
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Yang Gao
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - ShanHong Wu
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Xiaojun Cai
- Endocrinology Department, Heilongjiang Academy of Sciences of Traditional Chinese Medicine, Harbin, China
| | - TianYang Yu
- Heilongjiang University of Chinese Medicine, Harbin, China.,Acupuncture Department, Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China
| | - Liyuan Wang
- Heilongjiang University of Chinese Medicine, Harbin, China.,Ophthalmology Department, First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China
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Jia H, Ma Q, Liang Y, Wang D, Chang Q, Zhao B, Zhang Z, Liang J, Song J, Wang Y, Zhang R, Tu Z, Jiao Y. Clinical and genetic characteristics of Chinese patients with congenital cranial dysinnervation disorders. Orphanet J Rare Dis 2022; 17:431. [PMID: 36494820 PMCID: PMC9733177 DOI: 10.1186/s13023-022-02582-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 11/20/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Congenital cranial dysinnervation disorders (CCDDs) are a group of diseases with high clinical and genetic heterogeneity. Clinical examinations combined with Magnetic resonance imaging (MRI) and whole exome sequencing (WES) were performed to reveal the phenotypic and genotypic characteristics in a cohort of Chinese CCDDs patients. RESULTS A total of 122 CCDDs patients from 96 families were enrolled. All patients showed restrictive eye movements, and 46 patients from 46 families (47.9%, 46/96) were accompanied by multiple congenital malformations. Multi-positional high-resolution MRI was performed in 94 patients from 88 families, of which, all patients had hypoplasia of the cranial nerves except HGPPS patients and 15 patients from 15 families (17.0%,15/88) were accompanied by other craniocerebral malformations. WES was performed in 122 CCDDs patients. Ten pathogenic variants were detected in KIF21A, TUBB3, and CHN1 genes in 43 families. Three variants were unreported, including KIF21A (c.1064T > C, p.F355S), TUBB3 (c.232T > A, p.S78T) and CHN1 (c.650A > G, p.H217R). Of the 43 probands harboring pathogenic variants, 42 were diagnosed with Congenital Fibrosis of Extraocular Muscles (CFEOM) and one was Duane Retraction Syndrome (DRS). No definite pathogenic variants in known candidate genes of CCDDs were found in sporadic DRS, Möbius Syndrome (MBS) and Horizontal Gaze Palsy with Progressive Scoliosis (HGPPS) patients. The CFEOM patients harboring R380C, E410K and R262H variants in TUBB3 gene and F355S variant in KIF21A gene exhibited syndromic phenotypes. CONCLUSIONS This study broadened the phenotypic and genotypic spectrums of CCDDs, and it was the largest clinical and genetic investigation for CCDDs patients from China. KIF21A and TUBB3 were the common pathogenic genes in Chinese CFEOM. MRI coupled with WES can provide a supportive diagnosis in patients with clinically suspected CCDDs.
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Affiliation(s)
- Hongyan Jia
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Qian Ma
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Yi Liang
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Dan Wang
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Qinglin Chang
- grid.24696.3f0000 0004 0369 153XDepartment of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China
| | - Bo Zhao
- grid.24696.3f0000 0004 0369 153XDepartment of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China
| | - Zongrui Zhang
- grid.24696.3f0000 0004 0369 153XDepartment of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China
| | - Jing Liang
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Jing Song
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Yidi Wang
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Ranran Zhang
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
| | - Zhanhan Tu
- grid.9918.90000 0004 1936 8411Department of Neuroscience, Psychology and Behaviour, Ulverscroft Eye Unit, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX UK
| | - Yonghong Jiao
- grid.24696.3f0000 0004 0369 153XBeijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China ,grid.414373.60000 0004 1758 1243Beijing Ophthalmology and Visual Science Key Lab, Beijing, 100730 China
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Vemula SK, Kim SA, Muvavarirwa T, Bell JL, Whitman MC. Impaired Extraocular Muscle Innervation Is Present Before Eye Opening in a Mouse Model of Infantile Nystagmus Syndrome. Invest Ophthalmol Vis Sci 2022; 63:4. [PMID: 36083589 PMCID: PMC9469029 DOI: 10.1167/iovs.63.10.4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Purpose To determine if extraocular muscles (EOMs) from mice with nystagmus show abnormalities in myofiber composition and innervation, as seen in EOMs from human nystagmus patients, and to determine when in development those changes occur. Methods Balb/c albino mice were crossed to pigmented mice to generate heterozygous mice, which were mated to create experimental litters containing albinos and wild-type controls. Orbits were harvested from adult animals (12 weeks old); on postnatal day (P)0, P10, P14, and P21; and from 6-week-old animals. EOM sections were collected from the intraorbital portion of the muscles. Sections were immunostained for slow and fast myosin and for neuromuscular junctions (NMJs). The proportion of each myofiber subtype and the density and size of NMJs were quantified. Initial innervation patterns were assessed using whole-mount immunostaining of embryonic day (E)13.5 embryos expressing IslMN:GFP. Results Adult albino EOMs display an increased proportion of slow myofibers, larger slow myofibers, and a decreased density of NMJs—similar to human nystagmus patients. The percentage of NMJs on slow myofibers is also lower in albino animals. The initial innervation pattern of the incoming ocular motor neurons is normal in E13.5 albino embryos. Differences in the proportion of slow and fast myofiber subtypes are present as early as P14, and a lower percentage of NMJs on slow myofibers is present by P21. There is a lower density of NMJs on albino EOMs as early as P10, prior to eye opening. Conclusions Changes in NMJ development observed before eye opening indicate that nystagmus is not solely secondary to poor vision.
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Affiliation(s)
- Sampath Kumar Vemula
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Seoyoung A Kim
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Tapiwa Muvavarirwa
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Jessica L Bell
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
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9
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Carretero-Rodriguez L, Guðjónsdóttir R, Poparic I, Reilly ML, Chol M, Bianco IH, Chiapello M, Feret R, Deery MJ, Guthrie S. The Rac-GAP alpha2-Chimaerin Signals via CRMP2 and Stathmins in the Development of the Ocular Motor System. J Neurosci 2021; 41:6652-6672. [PMID: 34168008 PMCID: PMC8336708 DOI: 10.1523/jneurosci.0983-19.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 11/21/2022] Open
Abstract
A precise sequence of axon guidance events is required for the development of the ocular motor system. Three cranial nerves grow toward, and connect with, six extraocular muscles in a stereotyped pattern, to control eye movements. The signaling protein alpha2-chimaerin (α2-CHN) plays a pivotal role in the formation of the ocular motor system; mutations in CHN1, encoding α2-CHN, cause the human eye movement disorder Duane Retraction Syndrome (DRS). Our research has demonstrated that the manipulation of α2-chn signaling in the zebrafish embryo leads to ocular motor axon wiring defects, although the signaling cascades regulated by α2-chn remain poorly understood. Here, we demonstrate that several cytoskeletal regulatory proteins-collapsin response mediator protein 2 (CRMP2; encoded by the gene dpysl2), stathmin1, and stathmin 2-bind to α2-CHN. dpysl2, stathmin1, and especially stathmin2 are expressed by ocular motor neurons. We find that the manipulation of dpysl2 and of stathmins in zebrafish larvae leads to defects in both the axon wiring of the ocular motor system and the optokinetic reflex, impairing horizontal eye movements. Knockdowns of these molecules in zebrafish larvae of either sex caused axon guidance phenotypes that included defasciculation and ectopic branching; in some cases, these phenotypes were reminiscent of DRS. chn1 knock-down phenotypes were rescued by the overexpression of CRMP2 and STMN1, suggesting that these proteins act in the same signaling pathway. These findings suggest that CRMP2 and stathmins signal downstream of α2-CHN to orchestrate ocular motor axon guidance and to control eye movements.SIGNIFICANCE STATEMENT The precise control of eye movements is crucial for the life of vertebrate animals, including humans. In humans, this control depends on the arrangement of nerve wiring of the ocular motor system, composed of three nerves and six muscles, a system that is conserved across vertebrate phyla. Mutations in the protein alpha2-chimaerin have previously been shown to cause eye movement disorders (squint) and axon wiring defects in humans. Our recent work has unraveled how alpha2-chimaerin coordinates axon guidance of the ocular motor system in animal models. In this article, we demonstrate key roles for the proteins CRMP2 and stathmin 1/2 in the signaling pathway orchestrated by alpha2-chimaerin, potentially giving insight into the etiology of eye movement disorders in humans.
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Affiliation(s)
| | | | - Ivana Poparic
- Department of Developmental Neurobiology, King's College London, London SE1 1UL, United Kingdom
| | | | - Mary Chol
- Department of Developmental Neurobiology, King's College London, London SE1 1UL, United Kingdom
| | - Isaac H Bianco
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Marco Chiapello
- Cambridge Centre for Proteomics, Cambridge Systems Biology Centre, Department of Biochemistry, University of Cambridge, Cambridge CB2 1QR, United Kingdom
| | - Renata Feret
- Institute for Sustainable Plant Protection, National Research Council, 10135 Torino, Italy
| | - Michael J Deery
- Institute for Sustainable Plant Protection, National Research Council, 10135 Torino, Italy
| | - Sarah Guthrie
- School of Life Sciences, University of Sussex, Brighton BN7 9QG, United Kingdom
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10
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Zhao H, Wang L, Wang S, Chen X, Liang M, Zhang X, Wang J, Xu X. CHN1 promotes epithelial-mesenchymal transition via the Akt/GSK-3β/Snail pathway in cervical carcinoma. J Transl Med 2021; 19:295. [PMID: 34238315 PMCID: PMC8264971 DOI: 10.1186/s12967-021-02963-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/25/2021] [Indexed: 12/02/2022] Open
Abstract
Background Metastasis and invasion are crucial in determining the mortality of cervical carcinoma (CC) patients. The epithelial–mesenchymal transition (EMT) is now a universal explanation for the mechanisms of tumor metastasis. Α-chimeric protein (α-chimaerin, CHN1) plays an important role in the regulation of signal transduction and development. However, the molecular regulatory relationships between CHN1 and CC progression in relation to EMT have not yet been identified. Methods The expression of CHN1 in CC tissues, adjacent tissues, and lymph node metastases from CC patients was detected by immunohistochemistry. Upregulation and knockdown of CHN1 were achieved by transfection of CC cells. The effect of CHN1 on cell proliferation was determined by CCK-8 and plate clone formation assays. Changes in migration and invasion capabilities were evaluated using scratch migration and transwell invasion assays. The effect of CHN1 overexpression and interference on xenograft tumor growth was determined by tumor weight and pathological analyses. The expression of EMT-related mRNAs was measured by qRT-PCR in transfected CC cells. EMT-related proteins and Akt/GSK-3β/Snail signaling pathway-related proteins were also evaluated by western blotting. Results CHN1 was overexpressed in CC tissues and was associated with lymph node metastasis and low survival in CC patients. Overexpression of CHN1 promoted cell proliferation, migration, and invasion in CC cells. In contrast, silencing of CHN1 inhibited these phenomena. Overexpression of CHN1 promoted tumor formation in an in vivo xenograft tumor mouse model, with increased tumor volumes and weights. In addition, CHN1 induced the expression of EMT-related transcription factors, accompanied by the decreased expression of epithelial markers and increased expression of mesenchymal markers. The Akt/GSK-3β/Snail signaling pathway was activated by overexpression of CHN1 in vitro, and activation of this pathway was inhibited by the signaling pathway inhibitor LY294002. Conclusion These results suggest that CHN1 promotes the development and progression of cervical carcinoma via the Akt/GSK-3β/Snail pathway by inducing EMT. Supplementary Information The online version contains supplementary material available at 10.1186/s12967-021-02963-7.
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Affiliation(s)
- Haoqi Zhao
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.,Reproductive Physiology Laboratory, National Research Institute for Family Planning, Beijing, 100081, China.,National Engineering and Research Center of Continuous Casting Technology, China Iron and Steel Research Institute Group, Beijing, 100081, China
| | - Lan Wang
- Biopharmaceutical R&D Center, Chinese Academy of Medical Sciences & Peking Union Medical College, Suzhou, 215126, Jiangsu, China
| | - Shufang Wang
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.,Reproductive Physiology Laboratory, National Research Institute for Family Planning, Beijing, 100081, China.,Department of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Xihua Chen
- Reproductive Physiology Laboratory, National Research Institute for Family Planning, Beijing, 100081, China
| | - Min Liang
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.,Reproductive Physiology Laboratory, National Research Institute for Family Planning, Beijing, 100081, China
| | - Xin Zhang
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.,Reproductive Physiology Laboratory, National Research Institute for Family Planning, Beijing, 100081, China
| | - Jiedong Wang
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.,Reproductive Physiology Laboratory, National Research Institute for Family Planning, Beijing, 100081, China
| | - Xiangbo Xu
- Reproductive Physiology Laboratory, National Research Institute for Family Planning, Beijing, 100081, China.
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11
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Abstract
Abnormalities in cranial motor nerve development cause paralytic strabismus syndromes, collectively referred to as congenital cranial dysinnervation disorders, in which patients cannot fully move their eyes. These disorders can arise through one of two mechanisms: (a) defective motor neuron specification, usually by loss of a transcription factor necessary for brainstem patterning, or (b) axon growth and guidance abnormalities of the oculomotor, trochlear, and abducens nerves. This review focuses on our current understanding of axon guidance mechanisms in the cranial motor nerves and how disease-causing mutations disrupt axon targeting. Abnormalities of axon growth and guidance are often limited to a single nerve or subdivision, even when the causative gene is ubiquitously expressed. Additionally, when one nerve is absent, its normal target muscles attract other motor neurons. Study of these disorders highlights the complexities of axon guidance and how each population of neurons uses a unique but overlapping set of axon guidance pathways. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
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12
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Lysosomal Function and Axon Guidance: Is There a Meaningful Liaison? Biomolecules 2021; 11:biom11020191. [PMID: 33573025 PMCID: PMC7911486 DOI: 10.3390/biom11020191] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 01/25/2023] Open
Abstract
Axonal trajectories and neural circuit activities strongly rely on a complex system of molecular cues that finely orchestrate the patterning of neural commissures. Several of these axon guidance molecules undergo continuous recycling during brain development, according to incompletely understood intracellular mechanisms, that in part rely on endocytic and autophagic cascades. Based on their pivotal role in both pathways, lysosomes are emerging as a key hub in the sophisticated regulation of axonal guidance cue delivery, localization, and function. In this review, we will attempt to collect some of the most relevant research on the tight connection between lysosomal function and axon guidance regulation, providing some proof of concepts that may be helpful to understanding the relation between lysosomal storage disorders and neurodegenerative diseases.
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13
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Whitman MC, Miyake N, Nguyen EH, Bell JL, Matos Ruiz PM, Chan WM, Di Gioia SA, Mukherjee N, Barry BJ, Bosley TM, Khan AO, Engle EC. Decreased ACKR3 (CXCR7) function causes oculomotor synkinesis in mice and humans. Hum Mol Genet 2020; 28:3113-3125. [PMID: 31211835 DOI: 10.1093/hmg/ddz137] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/08/2019] [Accepted: 06/10/2019] [Indexed: 01/17/2023] Open
Abstract
Oculomotor synkinesis is the involuntary movement of the eyes or eyelids with a voluntary attempt at a different movement. The chemokine receptor CXCR4 and its ligand CXCL12 regulate oculomotor nerve development; mice with loss of either molecule have oculomotor synkinesis. In a consanguineous family with congenital ptosis and elevation of the ptotic eyelid with ipsilateral abduction, we identified a co-segregating homozygous missense variant (c.772G>A) in ACKR3, which encodes an atypical chemokine receptor that binds CXCL12 and functions as a scavenger receptor, regulating levels of CXCL12 available for CXCR4 signaling. The mutant protein (p.V258M) is expressed and traffics to the cell surface but has a lower binding affinity for CXCL12. Mice with loss of Ackr3 have variable phenotypes that include misrouting of the oculomotor and abducens nerves. All embryos show oculomotor nerve misrouting, ranging from complete misprojection in the midbrain, to aberrant peripheral branching, to a thin nerve, which aberrantly innervates the lateral rectus (as seen in Duane syndrome). The abducens nerve phenotype ranges from complete absence, to aberrant projections within the orbit, to a normal trajectory. Loss of ACKR3 in the midbrain leads to downregulation of CXCR4 protein, consistent with reports that excess CXCL12 causes ligand-induced degradation of CXCR4. Correspondingly, excess CXCL12 applied to ex vivo oculomotor slices causes axon misrouting, similar to inhibition of CXCR4. Thus, ACKR3, through its regulation of CXCL12 levels, is an important regulator of axon guidance in the oculomotor system; complete loss causes oculomotor synkinesis in mice, while reduced function causes oculomotor synkinesis in humans.
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Affiliation(s)
- Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Noriko Miyake
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Elaine H Nguyen
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Jessica L Bell
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Paola M Matos Ruiz
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Wai-Man Chan
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Silvio Alessandro Di Gioia
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Nisha Mukherjee
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Brenda J Barry
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - T M Bosley
- Department of Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Arif O Khan
- Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Elizabeth C Engle
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
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14
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Protocadherin-Mediated Cell Repulsion Controls the Central Topography and Efferent Projections of the Abducens Nucleus. Cell Rep 2020; 24:1562-1572. [PMID: 30089266 DOI: 10.1016/j.celrep.2018.07.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/31/2018] [Accepted: 07/06/2018] [Indexed: 11/21/2022] Open
Abstract
Cranial motor nuclei in the brainstem innervate diverse types of head and neck muscles. Failure in establishing these neuromuscular connections causes congenital cranial dysinnervation disorders (CCDDs) characterized by abnormal craniofacial movements. However, mechanisms that link cranial motor nuclei to target muscles are poorly understood at the molecular level. Here, we report that protocadherin-mediated repulsion mediates neuromuscular connection in the ocular motor system in zebrafish. We identify pools of abducens motor neurons that are topographically arranged according to soma size and convergently innervate a single muscle. Disruptions of Duane retraction syndrome-associated transcription factors reveal that these neurons require Mafba/MAFB, but not Sall4/SALL4, for differentiation. Furthermore, genetic perturbations of Pcdh17/protocadherin-17 result in defective axon growth and soma clumping, thereby abolishing neuromuscular connectivity. Our results suggest that protocadherin-mediated repulsion forms the central topography and efferent projection pattern of the abducens nucleus following Mafba-dependent specification and imply potential involvement of protocadherins in CCDD etiology.
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15
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Alreheli AQ, Aloufi MM, Aalam W, Kordi ES, Al-Habboubi HF. The clinical characteristics of Duane retraction syndrome in Al-Medina region. Saudi J Ophthalmol 2020; 33:338-341. [PMID: 31920443 PMCID: PMC6950951 DOI: 10.1016/j.sjopt.2019.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 02/02/2019] [Accepted: 07/22/2019] [Indexed: 11/15/2022] Open
Abstract
Purpose To assess the clinical characteristics of Duane Retraction Syndrome (DRS) in Al-Medina region, in patients attending a pediatric ophthalmology clinic at Ohud Hospital. Method A cross-sectional observational study was conducted from October 2017 to June 2018 at Ohud Hospital, Al-Medina region, Saudi Arabia. Data was collected using a sheet containing eighteen simple items which include demographic data, family history, surgical history, the clinical characteristics of the disease and the physician's treatment plan. Twenty patients were included in this study. Results All twenty patients included in the study were diagnosed with DRS type I. Male and female were symmetrical in numbers as both 10 (50.0%) respectively. The mean age of the subjects was 8.7 years (SD 9.6). 95% of the subject were unilaterally affected while five percent of them were affected both sides of the eyes. 75% of the patients were affected on the left eye while 20% were affected on the right side. 35% of the patients had amblyopia in the affected eye. 25% of the patients had an abnormal head position. Abnormal eye movement (upshoot and downshoot) more common when the right eye is affected (p-0.035). 75% of the patients were orthotropic while 30% had esotropia. 75% of patients were positive of parents' consanguinity. 16 patients (80.0%) were from Al-Medina city while four of them (20.0%) were from the different area of Al-Medina region (Al Hejeria, Al Henakia, Omluj, Yatmah). Conclusion This cross-sectional observational study is the first one that evaluates DRS in Al-Medina region. Associated abnormal eye movement more common when the right eye is affected. Parents' consanguinity may play a role in the occurrence of DRS as it is not considered as a rare disease in our region. Therefore, more studies are needed to establish the relationship between the occurrence of DRS and parents' consanguinity in our region. Also, further studies are needed to establish the relationship between abnormal eye movement and the involvement of the right eye.
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Affiliation(s)
| | | | - Waseem Aalam
- Faculty of Medicine, Jeddah University, Saudi Arabia
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16
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Ahmadi N, Huang J, North HJ, Lord D, Cheng AT. Avoiding blindness in managing epistaxis for a child with Duane's Retraction Syndrome. Int J Pediatr Otorhinolaryngol 2019; 126:109615. [PMID: 31416016 DOI: 10.1016/j.ijporl.2019.109615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/28/2019] [Accepted: 07/28/2019] [Indexed: 11/25/2022]
Abstract
Duane's Retraction Syndrome (DRS), a congenital cranial dysinnervation disorder, accounts for 5% of all strabismus. A vascular anomaly in DRS, which became clinically relevant in the context of significant epistaxis, is presented. A 15-year-old girl with DRS underwent a rhinological procedure for traumatic nasal deformity and suffered large volume epistaxis. Using angiography, an anatomical variation was identified, noting the ophthalmic artery was supplied by branches from the sphenopalatine artery, facial artery, and middle meningeal artery; not from the internal carotid artery. Hence epistaxis control was achieved via alternative methods, and unilateral blindness was avoided.
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Affiliation(s)
- Navid Ahmadi
- Department of Pediatric ENT, The Children's Hospital at Westmead, Sydney, New South Wales, Australia; Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.
| | - June Huang
- Department of Pediatric ENT, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Hannah Jd North
- Department of Pediatric ENT, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - David Lord
- Pediatric Interventional Radiology, Division of Medical Imaging, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Alan T Cheng
- Department of Pediatric ENT, The Children's Hospital at Westmead, Sydney, New South Wales, Australia; Discipline of Child and Adolescent Health, University of Sydney, Sydney, New South Wales, Australia
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17
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Whitman MC, Nguyen EH, Bell JL, Tenney AP, Gelber A, Engle EC. Loss of CXCR4/CXCL12 Signaling Causes Oculomotor Nerve Misrouting and Development of Motor Trigeminal to Oculomotor Synkinesis. Invest Ophthalmol Vis Sci 2019; 59:5201-5209. [PMID: 30372748 PMCID: PMC6204880 DOI: 10.1167/iovs.18-25190] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Proper control of eye movements is critical to vision, but relatively little is known about the molecular mechanisms that regulate development and axon guidance in the ocular motor system or cause the abnormal innervation patterns (oculomotor synkinesis) seen in developmental disorders and after oculomotor nerve palsy. We developed an ex vivo slice assay that allows for live imaging and molecular manipulation of the growing oculomotor nerve, which we used to identify axon guidance cues that affect the oculomotor nerve. Methods Ex vivo slices were generated from E10.5 IslMN-GFP embryos and grown for 24 to 72 hours. To assess for CXCR4 function, the specific inhibitor AMD3100 was added to the culture media. Cxcr4cko/cko:Isl-Cre:ISLMN-GFP and Cxcl12KO/KO:ISLMN-GFP embryos were cleared and imaged on a confocal microscope. Results When AMD3100 was added to the slice cultures, oculomotor axons grew dorsally (away from the eye) rather than ventrally (toward the eye). Axons that had already exited the midbrain continued toward the eye. Loss of Cxcr4 or Cxcl12 in vivo caused misrouting of the oculomotor nerve dorsally and motor axons from the trigeminal motor nerve, which normally innervate the muscles of mastication, aberrantly innervated extraocular muscles in the orbit. This represents the first mouse model of trigeminal-oculomotor synkinesis. Conclusions CXCR4/CXCL12 signaling is critical for the initial pathfinding decisions of oculomotor axons and their proper exit from the midbrain. Failure of the oculomotor nerve to innervate its extraocular muscle targets leads to aberrant innervation by other motor neurons, indicating that muscles lacking innervation may secrete cues that attract motor axons.
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Affiliation(s)
- Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Elaine H Nguyen
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Jessica L Bell
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Alan P Tenney
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
| | - Alon Gelber
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Elizabeth C Engle
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States.,Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States.,Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
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18
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Shaaban S, MacKinnon S, Andrews C, Staffieri SE, Maconachie GDE, Chan WM, Whitman MC, Morton SU, Yazar S, MacGregor S, Elder JE, Traboulsi EI, Gottlob I, Hewitt AW, Hunter DG, Mackey DA, Engle EC. Genome-Wide Association Study Identifies a Susceptibility Locus for Comitant Esotropia and Suggests a Parent-of-Origin Effect. Invest Ophthalmol Vis Sci 2018; 59:4054-4064. [PMID: 30098192 PMCID: PMC6088800 DOI: 10.1167/iovs.18-24082] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 06/19/2018] [Indexed: 11/24/2022] Open
Abstract
Purpose To identify genetic variants conferring susceptibility to esotropia. Esotropia is the most common form of comitant strabismus, has its highest incidence in European ancestry populations, and is believed to be inherited as a complex trait. Methods White European American discovery cohorts with nonaccommodative (826 cases and 2991 controls) or accommodative (224 cases and 749 controls) esotropia were investigated. White European Australian and United Kingdom cohorts with nonaccommodative (689 cases and 1448 controls) or accommodative (66 cases and 264 controls) esotropia were tested for replication. We performed a genome-wide case-control association study using a mixed linear additive model. Meta-analyses of discovery and replication cohorts were then conducted. Results A significant association with nonaccommodative esotropia was discovered (odds ratio [OR] = 1.41, P = 2.84 × 10-09) and replicated (OR = 1.23, P = 0.01) at rs2244352 [T] located within intron 1 of the WRB (tryptophan rich basic protein) gene on chromosome 21 (meta-analysis OR = 1.33, P = 9.58 × 10-11). This single nucleotide polymorphism (SNP) is differentially methylated, and there is a statistically significant skew toward paternal inheritance in the discovery cohort. Meta-analysis of the accommodative discovery and replication cohorts identified an association with rs912759 [T] (OR = 0.59, P = 1.89 × 10-08), an intergenic SNP on chromosome 1p31.1. Conclusions This is the first genome-wide association study (GWAS) to identify significant associations in esotropia and suggests a parent-of-origin effect. Additional cohorts will permit replication and extension of these findings. Future studies of rs2244352 and WRB should provide insight into pathophysiological mechanisms underlying comitant strabismus.
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Affiliation(s)
- Sherin Shaaban
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
- Dubai Harvard Foundation for Medical Research, Boston, Massachusetts, United States
| | - Sarah MacKinnon
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Caroline Andrews
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
| | - Sandra E. Staffieri
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Department of Ophthalmology, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Gail D. E. Maconachie
- Department of Neuroscience, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
| | - Wai-Man Chan
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
| | - Mary C. Whitman
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Sarah U. Morton
- Division of Newborn Medicine, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Seyhan Yazar
- Medical Research Council (MRC) Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
| | - Stuart MacGregor
- Stastical Genetics Laboratory, Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - James E. Elder
- Department of Ophthalmology, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia
- Department of Pediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Elias I. Traboulsi
- Department of Ophthalmology, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Irene Gottlob
- Department of Neuroscience, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
| | - Alex W. Hewitt
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
- Department of Ophthalmology, School of Medicine, Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - Strabismus Genetics Research Consortium
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
- Dubai Harvard Foundation for Medical Research, Boston, Massachusetts, United States
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Department of Ophthalmology, Royal Children's Hospital, University of Melbourne, Parkville, Victoria, Australia
- Department of Neuroscience, The University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester, United Kingdom
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
- Division of Newborn Medicine, Boston Children's Hospital, Boston, Massachusetts, United States
- Medical Research Council (MRC) Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, The University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
- Stastical Genetics Laboratory, Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Department of Pediatrics, The University of Melbourne, Parkville, Victoria, Australia
- Department of Ophthalmology, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
- Department of Ophthalmology, School of Medicine, Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
- Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, Massachusetts, United States
| | - David G. Hunter
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - David A. Mackey
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Western Australia, Australia
- Department of Ophthalmology, School of Medicine, Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - Elizabeth C. Engle
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
- Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, Massachusetts, United States
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19
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Whitman MC, Engle EC. Ocular congenital cranial dysinnervation disorders (CCDDs): insights into axon growth and guidance. Hum Mol Genet 2017; 26:R37-R44. [PMID: 28459979 DOI: 10.1093/hmg/ddx168] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 04/27/2017] [Indexed: 12/11/2022] Open
Abstract
Unraveling the genetics of the paralytic strabismus syndromes known as congenital cranial dysinnervation disorders (CCDDs) is both informing physicians and their patients and broadening our understanding of development of the ocular motor system. Genetic mutations underlying ocular CCDDs alter either motor neuron specification or motor nerve development, and highlight the importance of modulations of cell signaling, cytoskeletal transport, and microtubule dynamics for axon growth and guidance. Here we review recent advances in our understanding of two CCDDs, congenital fibrosis of the extraocular muscles (CFEOM) and Duane retraction syndrome (DRS), and discuss what they have taught us about mechanisms of axon guidance and selective vulnerability. CFEOM presents with congenital ptosis and restricted eye movements, and can be caused by heterozygous missense mutations in the kinesin motor protein KIF21A or in the β-tubulin isotypes TUBB3 or TUBB2B. CFEOM-causing mutations in these genes alter protein function and result in axon growth and guidance defects. DRS presents with inability to abduct one or both eyes. It can be caused by decreased function of several transcription factors critical for abducens motor neuron identity, including MAFB, or by heterozygous missense mutations in CHN1, which encodes α2-chimaerin, a Rac-GAP GTPase that affects cytoskeletal dynamics. Examination of the orbital innervation in mice lacking Mafb has established that the stereotypical misinnervation of the lateral rectus by fibers of the oculomotor nerve in DRS is secondary to absence of the abducens nerve. Studies of a CHN1 mouse model have begun to elucidate mechanisms of selective vulnerability in the nervous system.
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Affiliation(s)
- Mary C Whitman
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth C Engle
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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Nagata K, Takahashi M, Kiryu-Seo S, Kiyama H, Saido TC. Distinct functional consequences of ECEL1/DINE missense mutations in the pathogenesis of congenital contracture disorders. Acta Neuropathol Commun 2017; 5:83. [PMID: 29132416 PMCID: PMC5683451 DOI: 10.1186/s40478-017-0486-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/26/2017] [Indexed: 11/10/2022] Open
Abstract
Endothelin-converting enzyme-like 1 (ECEL1, also termed DINE in rodents), a membrane-bound metalloprotease, has been identified as a gene responsible for distal arthrogryposis (DA). ECEL1-mutated DA is generally characterized by ocular phenotypes in addition to the congenital limb contractures that are common to all DA subtypes. Until now, the consequences of the identified pathogenic mutations have remained incompletely understood because of a lack of detailed phenotypic analyses in relevant mouse models. In this study, we generated a new knock-in mouse strain that carries an ECEL1/DINE pathogenic G607S missense mutation, based on a previous study reporting atypical DA hindlimb phenotypes in two siblings with the mutation. We compared the morphological phenotypes of G607S knock-in mice with C760R knock-in mice that we previously established. Both C760R and G607S knock-in mouse embryos showed similar axonal arborization defects with normal trajectory patterns from the spinal cord to the target hindlimb muscles, as well as axon guidance defects of the abducens nerves. Intriguingly, distinct phenotypes in DINE protein localization and mRNA expression were identified in these knock-in mouse lines. For G607S, DINE mRNA and protein expression was decreased or almost absent in motor neurons. In the C760R mutant mice DINE was expressed and localized in the somata of motor neurons but not in axons. Our mutant mouse data suggest that ECEL1/DINE G607S and C760R mutations both lead to motor innervation defects as primary causes in ECEL1-mutated congenital contracture disorders. However, the functional consequences of the two mutations are distinct, with loss of axonal transport of ECEL1/DINE in C760R mutants and mRNA expression deficits in G607S mutants.
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Michalak SM, Whitman MC, Park JG, Tischfield MA, Nguyen EH, Engle EC. Ocular Motor Nerve Development in the Presence and Absence of Extraocular Muscle. Invest Ophthalmol Vis Sci 2017; 58:2388-2396. [PMID: 28437527 PMCID: PMC5403115 DOI: 10.1167/iovs.16-21268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose To spatially and temporally define ocular motor nerve development in the presence and absence of extraocular muscles (EOMs). Methods Myf5cre mice, which in the homozygous state lack EOMs, were crossed to an IslMN:GFP reporter line to fluorescently label motor neuron cell bodies and axons. Embryonic day (E) 11.5 to E15.5 wild-type and Myf5cre/cre:IslMN:GFP whole mount embryos and dissected orbits were imaged by confocal microscopy to visualize the developing oculomotor, trochlear, and abducens nerves in the presence and absence of EOMs. E11.5 and E18.5 brainstems were serially sectioned and stained for Islet1 to determine the fate of ocular motor neurons. Results At E11.5, all three ocular motor nerves in mutant embryos approached the orbit with a trajectory similar to that of wild-type. Subsequently, while wild-type nerves send terminal branches that contact target EOMs in a stereotypical pattern, the Myf5cre/cre ocular motor nerves failed to form terminal branches, regressed, and by E18.5 two-thirds of their corresponding motor neurons died. Comparisons between mutant and wild-type embryos revealed novel aspects of trochlear and oculomotor nerve development. Conclusions We delineated mouse ocular motor nerve spatial and temporal development in unprecedented detail. Moreover, we found that EOMs are not necessary for initial outgrowth and guidance of ocular motor axons from the brainstem to the orbit but are required for their terminal branching and survival. These data suggest that intermediate targets in the mesenchyme provide cues necessary for appropriate targeting of ocular motor axons to the orbit, while EOM cues are responsible for terminal branching and motor neuron survival.
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Affiliation(s)
- Suzanne M Michalak
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States 2F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States 3Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States 4University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States 5Howard Hughes Medical Institute, Chevy Chase, Maryland, United States
| | - Mary C Whitman
- F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States 6Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States 7Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Jong G Park
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States 2F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States 3Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States 5Howard Hughes Medical Institute, Chevy Chase, Maryland, United States 8Duke University School of Medicine, Durham, North Carolina, United States
| | - Max A Tischfield
- F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States 3Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States
| | - Elaine H Nguyen
- F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States 6Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Elizabeth C Engle
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States 2F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, United States 3Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States 5Howard Hughes Medical Institute, Chevy Chase, Maryland, United States 6Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States 7Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
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