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Gao J, Skidmore JM, Cimerman J, Ritter KE, Qiu J, Wilson LMQ, Raphael Y, Kwan KY, Martin DM. CHD7 and SOX2 act in a common gene regulatory network during mammalian semicircular canal and cochlear development. Proc Natl Acad Sci U S A 2024; 121:e2311720121. [PMID: 38408234 PMCID: PMC10927591 DOI: 10.1073/pnas.2311720121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 01/19/2024] [Indexed: 02/28/2024] Open
Abstract
Inner ear morphogenesis requires tightly regulated epigenetic and transcriptional control of gene expression. CHD7, an ATP-dependent chromodomain helicase DNA-binding protein, and SOX2, an SRY-related HMG box pioneer transcription factor, are known to contribute to vestibular and auditory system development, but their genetic interactions in the ear have not been explored. Here, we analyzed inner ear development and the transcriptional regulatory landscapes in mice with variable dosages of Chd7 and/or Sox2. We show that combined haploinsufficiency for Chd7 and Sox2 results in reduced otic cell proliferation, severe malformations of semicircular canals, and shortened cochleae with ectopic hair cells. Examination of mice with conditional, inducible Chd7 loss by Sox2CreER reveals a critical period (~E9.5) of susceptibility in the inner ear to combined Chd7 and Sox2 loss. Data from genome-wide RNA-sequencing and CUT&Tag studies in the otocyst show that CHD7 regulates Sox2 expression and acts early in a gene regulatory network to control expression of key otic patterning genes, including Pax2 and Otx2. CHD7 and SOX2 directly bind independently and cooperatively at transcription start sites and enhancers to regulate otic progenitor cell gene expression. Together, our findings reveal essential roles for Chd7 and Sox2 in early inner ear development and may be applicable for syndromic and other forms of hearing or balance disorders.
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Affiliation(s)
- Jingxia Gao
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI48109
| | | | - Jelka Cimerman
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI48109
| | - K. Elaine Ritter
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI48109
| | - Jingyun Qiu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ08854
- Keck Center for Collaborative Neuroscience, Stem Cell Research Center, Rutgers University, Piscataway, NJ08854
| | - Lindsey M. Q. Wilson
- Medical Scientist Training Program, The University of Michigan, Ann Arbor, MI48109
| | - Yehoash Raphael
- Department of Otolaryngology-Head and Neck Surgery, The University of Michigan, Ann Arbor, MI48109
| | - Kelvin Y. Kwan
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ08854
- Keck Center for Collaborative Neuroscience, Stem Cell Research Center, Rutgers University, Piscataway, NJ08854
| | - Donna M. Martin
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI48109
- Department of Human Genetics, The University of Michigan, Ann Arbor, MI48109
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Lewis MA, Juliano A, Robson C, Clement E, Nash R, Rajput K, D'Arco F. The spectrum of cochlear malformations in CHARGE syndrome and insights into the role of the CHD7 gene during embryogenesis of the inner ear. Neuroradiology 2023; 65:819-834. [PMID: 36715725 DOI: 10.1007/s00234-023-03118-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/09/2023] [Indexed: 01/31/2023]
Abstract
PURPOSE We reviewed the genotypes and the imaging appearances of cochleae in CHARGE patients from two large tertiary centres and analysed the observed cochlear anomalies, providing detailed anatomical description and a grading system. The goal was to gain insight into the spectrum of cochlear anomalies in CHARGE syndrome, and thus, in the role of the CHD7 gene in otic vesicle development. METHODS We retrospectively reviewed CT and/or MR imaging of CHARGE patients referred to our institutions between 2005 and 2022. Cochlear morphology was analysed and, when abnormal, divided into 3 groups in order of progressive severity. Other radiological findings in the temporal bone were also recorded. Comparison with the existing classification system of cochlear malformation was also attempted. RESULTS Cochlear morphology in our CHARGE cohort ranged from normal to extreme hypoplasia. The most common phenotype was cochlear hypoplasia in which the basal turn was relatively preserved, and the upper turns were underdeveloped. All patients in the cohort had absent or markedly hypoplastic semicircular canals and small, misshapen vestibules. Aside from a stenotic cochlear aperture (fossette) being associated with a hypoplastic or absent cochlear nerve, there was no consistent relationship between cochlear nerve status (normal, hypoplasia, or aplasia) and cochlear morphology. CONCLUSION Cochlear morphology in CHARGE syndrome is variable. Whenever the cochlea was abnormal, it was almost invariably hypoplastic. This may shed light on the role of CHD7 in cochlear development. Accurate morphological description of the cochlea contributes to proper clinical diagnosis and is important for planning surgical treatment options.
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Affiliation(s)
- Martin A Lewis
- Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond St. London, London, WC1N3JH, UK
| | - Amy Juliano
- Department of Radiology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Caroline Robson
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Emma Clement
- Department of Clinical Genetics, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Robert Nash
- Department of Audiological Medicine, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Kaukab Rajput
- Department of Audiological Medicine, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Felice D'Arco
- Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond St. London, London, WC1N3JH, UK. felice.d'
- Department of Radiology, Guy's and St. Thomas' NHS Foundation Trust, London, UK. felice.d'
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3
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Balendran V, Ritter KE, Martin DM. Epigenetic mechanisms of inner ear development. Hear Res 2022; 426:108440. [PMID: 35063312 PMCID: PMC9276839 DOI: 10.1016/j.heares.2022.108440] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 12/21/2021] [Accepted: 01/11/2022] [Indexed: 12/16/2022]
Abstract
Epigenetic factors are critically important for embryonic and postnatal development. Over the past decade, substantial technological advancements have occurred that now permit the study of epigenetic mechanisms that govern all aspects of inner ear development, from otocyst patterning to maturation and maintenance of hair cell stereocilia. In this review, we highlight how three major classes of epigenetic regulation (DNA methylation, histone modification, and chromatin remodeling) are essential for the development of the inner ear. We highlight open avenues for research and discuss how new tools enable the employment of epigenetic factors in regenerative and therapeutic approaches for hearing and balance disorders.
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Affiliation(s)
- Vinodh Balendran
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, United States
| | - K Elaine Ritter
- Department of Pediatrics, Medical Center Drive, University of Michigan Medical School, 8220C MSRB III, 1150 W, Ann Arbor, MI 48109-5652, United States
| | - Donna M Martin
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, United States; Department of Pediatrics, Medical Center Drive, University of Michigan Medical School, 8220C MSRB III, 1150 W, Ann Arbor, MI 48109-5652, United States; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, United States.
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4
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Nie J, Ueda Y, Solivais AJ, Hashino E. CHD7 regulates otic lineage specification and hair cell differentiation in human inner ear organoids. Nat Commun 2022; 13:7053. [PMID: 36396635 PMCID: PMC9672366 DOI: 10.1038/s41467-022-34759-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 11/07/2022] [Indexed: 11/19/2022] Open
Abstract
Mutations in CHD7 cause CHARGE syndrome, affecting multiple organs including the inner ear in humans. We investigate how CHD7 mutations affect inner ear development using human pluripotent stem cell-derived organoids as a model system. We find that loss of CHD7 or its chromatin remodeling activity leads to complete absence of hair cells and supporting cells, which can be explained by dysregulation of key otic development-associated genes in mutant otic progenitors. Further analysis of the mutant otic progenitors suggests that CHD7 can regulate otic genes through a chromatin remodeling-independent mechanism. Results from transcriptome profiling of hair cells reveal disruption of deafness gene expression as a potential underlying mechanism of CHARGE-associated sensorineural hearing loss. Notably, co-differentiating CHD7 knockout and wild-type cells in chimeric organoids partially rescues mutant phenotypes by restoring otherwise severely dysregulated otic genes. Taken together, our results suggest that CHD7 plays a critical role in regulating human otic lineage specification and hair cell differentiation.
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Affiliation(s)
- Jing Nie
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Yoshitomo Ueda
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Alexander J Solivais
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Eri Hashino
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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5
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Kimura Y, Kaga K. Comparison of vestibular ocular reflex and gross motor development in children with semicircular canal aplasia and hypoplasia. Int J Pediatr Otorhinolaryngol 2022; 162:111303. [PMID: 36137473 DOI: 10.1016/j.ijporl.2022.111303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 08/17/2022] [Accepted: 08/28/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To examine the effect of vestibular ocular reflex on gross motor development in children with semicircular canal aplasia and hypoplasia. STUDY DESIGN Case series. MATERIALS AND METHODS Children with congenital hearing loss underwent temporal bone computed tomography to assess their inner ear morphology. In this study, we examined eight children with bilateral complete aplasia of semicircular canals and seven children with bilateral hypoplasia of semicircular canals. Their vestibular ocular reflex was assessed using a damped rotational chair test. Their gross motor development was assessed by examining their ages of acquisition of head control and independent walking. RESULTS All eight children with semicircular canal aplasia were diagnosed as having CHARGE syndrome and five children were found to have CHD7 mutations. Cochlear morphological examination showed that cochlear hypoplasia type III was the most common in eight of 16 ears in children with semicircular canal aplasia. In semicircular canal hypoplasia, incomplete partition type II was found in seven of 14 ears. All eight children with semicircular canal aplasia showed no response in the damped rotational chair test. Even the three children followed up were unresponsive in all tests. In the group with semicircular canal hypoplasia, three children showed normal responses, one child showed no response, and three children showed poor responses. The mean age of acquisition of head control was 9.1 ± 6.3 months and that of independent walking was 31 ± 8.1 months in children with semicircular canal aplasia. The mean age of acquisition of head control was 6.0 ± 2.8 months and that of independent walking was 19.9 ± 4.9 months in children with semicircular canal hypoplasia. CONCLUSIONS We found that children with semicircular canal aplasia have severe dysfunction of the vestibular ocular reflex, and vestibular sensory cells derived from the semicircular canal may not be present. Semicircular canal hypoplasia is associated with dysfunction of the vestibular ocular reflex, but vestibular sensory cells may be present, and rotary nystagmus develops with growth similar to that observed in normal children previously reported. Semicircular canal aplasia is associated with CHARGE syndrome, and affected children tended to have a slower gross motor development. It was suggested that the combination of visual impairment and mental retardation may delay the development of central-level integrated functions and may further delay motor development.
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Affiliation(s)
- Yusuke Kimura
- National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan; Department of Otolaryngology-Head and Neck Surgery, Nihon University School of Medicine, Tokyo, Japan.
| | - Kimitaka Kaga
- National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan.
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Balendran V, Skidmore JM, Ritter KE, Gao J, Cimerman J, Beyer LA, Hurd EA, Raphael Y, Martin DM. Chromatin remodeler CHD7 is critical for cochlear morphogenesis and neurosensory patterning. Dev Biol 2021; 477:11-21. [PMID: 34004180 DOI: 10.1016/j.ydbio.2021.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 04/12/2021] [Accepted: 05/10/2021] [Indexed: 11/18/2022]
Abstract
Epigenetic regulation of gene transcription by chromatin remodeling proteins has recently emerged as an important contributing factor in inner ear development. Pathogenic variants in CHD7, the gene encoding Chromodomain Helicase DNA binding protein 7, cause CHARGE syndrome, which presents with malformations in the developing ear. Chd7 is broadly expressed in the developing mouse otocyst and mature auditory epithelium, yet the pathogenic effects of Chd7 loss in the cochlea are not well understood. Here we characterized cochlear epithelial phenotypes in mice with deletion of Chd7 throughout the otocyst (using Foxg1Cre/+ and Pax2Cre), in the otic mesenchyme (using TCre), in hair cells (using Atoh1Cre), in developing neuroblasts (using NgnCre), or in spiral ganglion neurons (using ShhCre/+). Pan-otic deletion of Chd7 resulted in shortened cochleae with aberrant projections and axonal looping, disorganized, supernumerary hair cells at the apical turn and a narrowed epithelium with missing hair cells in the middle region. Deletion of Chd7 in the otic mesenchyme had no effect on overall cochlear morphology. Loss of Chd7 in hair cells did not disrupt their formation or organization of the auditory epithelium. Similarly, absence of Chd7 in spiral ganglion neurons had no effect on axonal projections. In contrast, deletion of Chd7 in developing neuroblasts led to smaller spiral ganglia and disorganized cochlear neurites. Together, these observations reveal dosage-, tissue-, and time-sensitive cell autonomous roles for Chd7 in cochlear elongation and cochlear neuron organization, with minimal functions for Chd7 in hair cells. These studies provide novel information about roles for Chd7 in development of auditory neurons.
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Affiliation(s)
- Vinodh Balendran
- Departments of Pediatrics, The University of Michigan, Ann Arbor, MI, USA
| | | | - K Elaine Ritter
- Departments of Pediatrics, The University of Michigan, Ann Arbor, MI, USA
| | - Jingxia Gao
- Departments of Pediatrics, The University of Michigan, Ann Arbor, MI, USA
| | - Jelka Cimerman
- Departments of Pediatrics, The University of Michigan, Ann Arbor, MI, USA
| | - Lisa A Beyer
- Otolaryngology - Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA
| | | | - Yehoash Raphael
- Otolaryngology - Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA
| | - Donna M Martin
- Departments of Pediatrics, The University of Michigan, Ann Arbor, MI, USA; Otolaryngology - Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA; Human Genetics, The University of Michigan, Ann Arbor, MI, USA.
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7
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Notch Signalling: The Multitask Manager of Inner Ear Development and Regeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1218:129-157. [DOI: 10.1007/978-3-030-34436-8_8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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8
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Hardy H, Prendergast JG, Patel A, Dutta S, Trejo-Reveles V, Kroeger H, Yung AR, Goodrich LV, Brooks B, Sowden JC, Rainger J. Detailed analysis of chick optic fissure closure reveals Netrin-1 as an essential mediator of epithelial fusion. eLife 2019; 8:43877. [PMID: 31162046 PMCID: PMC6606025 DOI: 10.7554/elife.43877] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 06/03/2019] [Indexed: 12/13/2022] Open
Abstract
Epithelial fusion underlies many vital organogenic processes during embryogenesis. Disruptions to these cause a significant number of human birth defects, including ocular coloboma. We provide robust spatial-temporal staging and unique anatomical detail of optic fissure closure (OFC) in the embryonic chick, including evidence for roles of apoptosis and epithelial remodelling. We performed complementary transcriptomic profiling and show that Netrin-1 (NTN1) is precisely expressed in the chick fissure margin during fusion but is immediately downregulated after fusion. We further provide a combination of protein localisation and phenotypic evidence in chick, humans, mice and zebrafish that Netrin-1 has an evolutionarily conserved and essential requirement for OFC, and is likely to have an important role in palate fusion. Our data suggest that NTN1 is a strong candidate locus for human coloboma and other multi-system developmental fusion defects, and show that chick OFC is a powerful model for epithelial fusion research. Our bodies are made of many different groups of cells, which are arranged into tissues that perform specific roles. As tissues form in the embryo they must adopt precise three-dimensional structures, depending on their position in the body. In many cases this involves two edges of tissue fusing together to prevent gaps being present in the final structure. In individuals with a condition called ocular coloboma some of the tissues in the eyes fail to merge together correctly, leading to wide gaps that can severely affect vision. There are currently no treatments available for ocular coloboma and in over 70% of patients the cause of the defect is not known. Identifying new genes that control how tissues fuse may help researchers to find what causes this condition and multiple other tissue fusion defects, and establish whether these may be preventable in the future. Much of what is currently known about how tissues fuse has come from studying mice and zebrafish embryos. Although the extensive genetic tools available in these ‘models’ have proved very useful, both offer only a limited time window for observing tissues as they fuse, and the regions involved are very small. Chick embryos, on the other hand, are much larger than mouse or zebrafish embryos and are easier to access from within their eggs. This led Hardy et al. to investigate whether the developing chick eye could be a more useful model for studying the precise details of how tissues merge. Examining chick embryos revealed that tissues in the base of their eyes fuse between five and eight days after the egg had been fertilised, a comparatively long time compared to existing models. Also, many of the genes that Hardy et al. found switched on in chick eyes as the tissues merged had previously been identified as being essential for tissue fusion in humans. However, several new genes were also shown to be involved in the fusing process. For example, Netrin-1 was important for tissues to fuse in the eyes as well as in other regions of the developing embryo. These findings demonstrate that the chick eye is an excellent new model system to study how tissues fuse in animals. Furthermore, the genes identified by Hardy et al. may help researchers to identify the genetic causes of ocular coloboma and other tissue fusion defects in humans.
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Affiliation(s)
- Holly Hardy
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - James Gd Prendergast
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Aara Patel
- Birth Defects Research Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Sunit Dutta
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Violeta Trejo-Reveles
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Hannah Kroeger
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Andrea R Yung
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Brian Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Jane C Sowden
- Birth Defects Research Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Joe Rainger
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
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Ocak E, Duman D, Tekin M. Genetic Causes of Inner Ear Anomalies: a Review from the Turkish Study Group for Inner Ear Anomalies. Balkan Med J 2019; 36:206-211. [PMID: 31131597 PMCID: PMC6636654 DOI: 10.4274/balkanmedj.galenos.2019.2019.4.66] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Inner ear anomalies diagnosed using a radiological study are detected in almost 30% of cases with congenital or prelingual-onset sensorineural hearing loss. Inner ear anomalies can be isolated or occur along with a part of a syndrome involving other systems. Although astonishing progress has been made in research aimed at revealing the genetic causes of hearing loss in the past few decades, only a few genes have been linked to inner ear anomalies. The aim of this review is to discuss the known genetic causes of inner ear anomalies. Identifying the genetic causes of inner ear anomalies is important for guiding clinical care that includes empowered reproductive decisions provided to the affected individuals. Furthermore, understanding the molecular underpinnings of the development of the inner ear in humans is important to develop novel treatment strategies for people with hearing loss.
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Affiliation(s)
- Emre Ocak
- Department of Otolaryngology, Ankara University School of Medicine, Ankara, Turkey
| | - Duygu Duman
- Division of Genetics, Department of Pediatrics, Ankara University School of Medicine, Ankara, Turkey,Department of Audiology, Ankara University Faculty of Health Sciences, Ankara, Turkey
| | - Mustafa Tekin
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA,Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, USA,Dr. John T. Macdonald Department of Human Genetics, University of Miami Miller School of Medicine, Miami, USA
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10
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Tawfik KO, Leader BA, Walters ZA, Choo DI. Relative Preservation of Superior Semicircular Canal Architecture in CHARGE Syndrome. Otolaryngol Head Neck Surg 2019; 160:1095-1100. [PMID: 30667318 DOI: 10.1177/0194599818824306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES (1) Describe common patterns of semicircular canal (SCC) anomalies in CHARGE syndrome (CS) and (2) recognize that in CS, the architecture of the superior SCC may be relatively preserved. STUDY DESIGN This is a retrospective review of temporal bone imaging studies. SETTING Quaternary care center. SUBJECTS AND METHODS A sample of 37 patients with CS. All subjects met clinical diagnostic criteria for CS. The presence/absence of anomalies of the middle ear, mastoid, temporal bone venous anatomy, inner ear, and internal auditory canal was recorded. Anomalies of each SCC were considered separately and by severity (normal, dysplasia, aplasia). RESULTS Thirty-seven subjects (74 temporal bones) were reviewed. Thirty-four (92.0%) patients demonstrated bilateral SCC anomalies. Three (8.0%) had normal SCCs. In patients with SCC anomalies, all canals demonstrated bilateral abnormalities. Thirty-two (86.5%) patients had bilateral horizontal SCC aplasia. These 32 patients also demonstrated posterior SCC aplasia in at least 1 ear. Of 74 temporal bones, 37 (50.0%) had superior SCC dysplasia. All dysplastic superior SCCs showed preservation of the anterior limb. Complete superior SCC aplasia was found in 28 (37.8%) temporal bones. CONCLUSION SCC anomalies occur with high frequency in CS. Complete absence of the horizontal and posterior canals is typical and usually bilateral. By contrast, the superior SCC often demonstrates relative preservation of the anterior limb.
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Affiliation(s)
- Kareem O Tawfik
- 1 Division of Otolaryngology-Head & Neck Surgery, University of California, San Diego School of Medicine, San Diego, California, USA
| | - Brittany A Leader
- 2 Department of Otolaryngology-Head & Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Zoe A Walters
- 3 University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Daniel I Choo
- 2 Department of Otolaryngology-Head & Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,4 Division of Pediatric Otolaryngology-Head & Neck Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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11
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Lilian SJ, Seal HE, Popratiloff A, Hirsch JC, Peusner KD. A New Model for Congenital Vestibular Disorders. J Assoc Res Otolaryngol 2018; 20:133-149. [PMID: 30564989 DOI: 10.1007/s10162-018-00705-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 10/18/2018] [Indexed: 12/18/2022] Open
Abstract
Many developmental disorders of the inner ear are manifested clinically as delayed motor development and challenges in maintaining posture and balance, indicating involvement of central vestibular circuits. How the vestibular circuitry is rewired in pediatric cases is poorly understood due to lack of a suitable animal model. Based on this, our lab designed and validated a chick embryo model to study vestibular development in congenital vestibular disorders. The developing inner ear or "otocyst" on the right side of 2-day-old chick embryos (E2) was surgically rotated 180° in the anterior-posterior axis, forming the "anterior-posterior axis rotated otocyst chick" or ARO chick. The ARO chick has a reproducible pathology of a sac with truncated or missing semicircular canals. A sac is the most common inner ear defect found in children with congenital vestibular disorders. In E13 ARO chicks, the sac contained all three cristae and maculae utriculi and sacculi, but the superior crista and macula utriculi were shortened in anterior-posterior extent. Also, the number of principal cells of the tangential vestibular nucleus, a major avian vestibular nucleus, was decreased 66 % on the rotated side. After hatching, no difference was detected between ARO and normal chicks in their righting reflex times. However, unlike normal chicks, ARO hatchlings had a constant, right head tilt, and after performing the righting reflex, ARO chicks stumbled and walked with a widened base. Identifying the structure and function of abnormally developed brain regions in ARO chicks may assist in improving treatments for patients with congenital vestibular disorder.
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Affiliation(s)
- Sigmund J Lilian
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I Street NW, Washington, DC, 20037, USA.,Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Hayley E Seal
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I Street NW, Washington, DC, 20037, USA
| | - Anastas Popratiloff
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I Street NW, Washington, DC, 20037, USA
| | - June C Hirsch
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I Street NW, Washington, DC, 20037, USA
| | - Kenna D Peusner
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I Street NW, Washington, DC, 20037, USA.
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12
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Durruthy-Durruthy R, Sperry ED, Bowen ME, Attardi LD, Heller S, Martin DM. Single Cell Transcriptomics Reveal Abnormalities in Neurosensory Patterning of the Chd7 Mutant Mouse Ear. Front Genet 2018; 9:473. [PMID: 30459807 PMCID: PMC6232929 DOI: 10.3389/fgene.2018.00473] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 09/25/2018] [Indexed: 12/11/2022] Open
Abstract
The chromatin remodeling protein CHD7 is critical for proper formation of the mammalian inner ear. Humans with heterozygous pathogenic variants in CHD7 exhibit CHARGE syndrome, characterized by hearing loss and inner ear dysplasia, including abnormalities of the semicircular canals and Mondini malformations. Chd7Gt/+ heterozygous null mutant mice also exhibit dysplastic semicircular canals and hearing loss. Prior studies have demonstrated that reduced Chd7 dosage in the ear disrupts expression of genes involved in morphogenesis and neurogenesis, yet the relationships between these changes in gene expression and otic patterning are not well understood. Here, we sought to define roles for CHD7 in global regulation of gene expression and patterning in the developing mouse ear. Using single-cell multiplex qRT-PCR, we analyzed expression of 192 genes in FAC sorted cells from Pax2Cre;mT/mGFP wild type and Chd7Gt/+ mutant microdissected mouse otocysts. We found that Chd7 haploinsufficient otocysts exhibit a relative enrichment of cells adopting a neuroblast (vs. otic) transcriptional identity compared with wild type. Additionally, we uncovered disruptions in pro-sensory and pro-neurogenic gene expression with Chd7 loss, including genes encoding proteins that function in Notch signaling. Our results suggest that Chd7 is required for early cell fate decisions in the developing ear that involve highly specific aspects of otic patterning and differentiation.
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Affiliation(s)
- Robert Durruthy-Durruthy
- Departments of Otolaryngology - Head and Neck Surgery, Stanford University, Stanford, CA, United States
| | - Ethan D Sperry
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI, United States.,Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States
| | - Margot E Bowen
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University, Stanford, CA, United States
| | - Laura D Attardi
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University, Stanford, CA, United States
| | - Stefan Heller
- Departments of Otolaryngology - Head and Neck Surgery, Stanford University, Stanford, CA, United States
| | - Donna M Martin
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI, United States.,Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States.,Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, United States
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Jordan VK, Fregeau B, Ge X, Giordano J, Wapner RJ, Balci TB, Carter MT, Bernat JA, Moccia AN, Srivastava A, Martin DM, Bielas SL, Pappas J, Svoboda MD, Rio M, Boddaert N, Cantagrel V, Lewis AM, Scaglia F, Kohler JN, Bernstein JA, Dries AM, Rosenfeld JA, DeFilippo C, Thorson W, Yang Y, Sherr EH, Bi W, Scott DA. Genotype-phenotype correlations in individuals with pathogenic RERE variants. Hum Mutat 2018; 39:666-675. [PMID: 29330883 PMCID: PMC5903952 DOI: 10.1002/humu.23400] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/28/2017] [Accepted: 01/02/2018] [Indexed: 12/21/2022]
Abstract
Heterozygous variants in the arginine-glutamic acid dipeptide repeats gene (RERE) have been shown to cause neurodevelopmental disorder with or without anomalies of the brain, eye, or heart (NEDBEH). Here, we report nine individuals with NEDBEH who carry partial deletions or deleterious sequence variants in RERE. These variants were found to be de novo in all cases in which parental samples were available. An analysis of data from individuals with NEDBEH suggests that point mutations affecting the Atrophin-1 domain of RERE are associated with an increased risk of structural eye defects, congenital heart defects, renal anomalies, and sensorineural hearing loss when compared with loss-of-function variants that are likely to lead to haploinsufficiency. A high percentage of RERE pathogenic variants affect a histidine-rich region in the Atrophin-1 domain. We have also identified a recurrent two-amino-acid duplication in this region that is associated with the development of a CHARGE syndrome-like phenotype. We conclude that mutations affecting RERE result in a spectrum of clinical phenotypes. Genotype-phenotype correlations exist and can be used to guide medical decision making. Consideration should also be given to screening for RERE variants in individuals who fulfill diagnostic criteria for CHARGE syndrome but do not carry pathogenic variants in CHD7.
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Affiliation(s)
- Valerie K. Jordan
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
| | - Brieana Fregeau
- Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Xiaoyan Ge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics, Houston, Texas
| | - Jessica Giordano
- Institute of Genomic Medicine and Department of OB/GYN, Columbia University Medical Center, New York, New York
| | - Ronald J. Wapner
- Institute of Genomic Medicine and Department of OB/GYN, Columbia University Medical Center, New York, New York
| | - Tugce B. Balci
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Melissa T. Carter
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - John A. Bernat
- Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
| | - Amanda N. Moccia
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Anshika Srivastava
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Donna M. Martin
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Stephanie L. Bielas
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
| | - John Pappas
- New York University School of Medicine, New York, New York
| | - Melissa D. Svoboda
- Department of Pediatrics, Children’s Hospital of San Antonio/Baylor College of Medicine, San Antonio, Texas
| | - Marlène Rio
- Laboratory of Developmental Brain Disorders, INSERM UMR 1163, Paris, France
- Service de Génétique, Necker Enfants Malades University Hospital, APHP, Paris, France
| | - Nathalie Boddaert
- Laboratory of Developmental Brain Disorders, INSERM UMR 1163, Paris, France
- Pediatric Radiology, Necker Enfants Malades University Hospital, APHP, Paris, France
| | - Vincent Cantagrel
- Laboratory of Developmental Brain Disorders, INSERM UMR 1163, Paris, France
- Paris Descartes - Sorbonne Paris Cité UniversityImagine Institute, Paris, France
| | - Andrea M. Lewis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
| | | | | | | | - Annika M. Dries
- Stanford University School of Medicine, Stanford, California
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Colette DeFilippo
- Stanford Children’s Health/Lucile Packard Children’s Hospital Stanford, Palo Alto, California
| | - Willa Thorson
- University of MiamiMiller School of Medicine, Miami, Florida
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics, Houston, Texas
| | - Elliott H. Sherr
- Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics, Houston, Texas
| | - Daryl A. Scott
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
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van Ravenswaaij-Arts C, Martin DM. New insights and advances in CHARGE syndrome: Diagnosis, etiologies, treatments, and research discoveries. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2017; 175:397-406. [PMID: 29171162 DOI: 10.1002/ajmg.c.31592] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/02/2017] [Accepted: 10/04/2017] [Indexed: 01/17/2023]
Abstract
CHARGE syndrome is a multiple congenital anomaly condition caused, in a majority of individuals, by loss of function pathogenic variants in the gene CHD7. In this special issue of the American Journal of Medical Genetics part C, authors of eleven manuscripts describe specific organ system features of CHARGE syndrome, with a focus on recent developments in diagnosis, etiologies, and treatments. Since 2004, when CHD7 was identified as the major causative gene in CHARGE, several animal models (mice, zebrafish, flies, and frog) and cell-based systems have been developed to explore the underlying pathophysiology of this condition. In this article, we summarize those advances, highlight opportunities for new discoveries, and encourage readers to explore specific organ systems in more detail in each individual article. We hope the excitement around innovative research and development in CHARGE syndrome will encourage others to join this effort, and will stimulate other investigators and professionals to engage with individuals diagnosed as having CHARGE syndrome, their families, and their care providers.
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Affiliation(s)
- Conny van Ravenswaaij-Arts
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Donna M Martin
- Departments of Human Genetics, The University of Michigan Medical School, Ann Arbor, Michigan.,Departments of Pediatrics, The University of Michigan Medical School, Ann Arbor, Michigan
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Nishitani AM, Ohta S, Yung AR, Del Rio T, Gordon MI, Abraira VE, Avilés EC, Schoenwolf GC, Fekete DM, Goodrich LV. Distinct functions for netrin 1 in chicken and murine semicircular canal morphogenesis. Development 2017; 144:3349-3360. [PMID: 28851705 DOI: 10.1242/dev.144519] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 08/11/2017] [Indexed: 12/16/2022]
Abstract
The vestibular system of the inner ear detects head position using three orthogonally oriented semicircular canals; even slight changes in their shape and orientation can cause debilitating behavioral defects. During development, the canals are sculpted from pouches that protrude from the otic vesicle, the embryonic anlage of the inner ear. In the center of each pouch, a fusion plate forms where cells lose their epithelial morphology and the basement membrane breaks down. Cells in the fusing epithelia intercalate and are removed, creating a canal. In mice, fusion depends on the secreted protein netrin 1 (Ntn1), which is necessary for basement membrane breakdown, although the underlying molecular mechanism is unknown. Using gain-of-function approaches, we found that overexpression of Ntn1 in the chick otic vesicle prevented canal fusion by inhibiting apoptosis. In contrast, ectopic expression of the same chicken Ntn1 in the mouse otic vesicle, where apoptosis is less prominent, resulted in canal truncation. These findings highlight the importance of apoptosis for tissue morphogenesis and suggest that Ntn1 may play divergent cellular roles despite its conserved expression during canal morphogenesis in chicken and mouse.
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Affiliation(s)
| | - Sho Ohta
- Departments of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Andrea R Yung
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Tony Del Rio
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Michael I Gordon
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Victoria E Abraira
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Evelyn C Avilés
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Gary C Schoenwolf
- Departments of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Donna M Fekete
- Department of Biological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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16
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Sculpting the labyrinth: Morphogenesis of the developing inner ear. Semin Cell Dev Biol 2017; 65:47-59. [DOI: 10.1016/j.semcdb.2016.09.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/26/2016] [Accepted: 09/25/2016] [Indexed: 01/23/2023]
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17
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Doetzlhofer A, Avraham KB. Insights into inner ear-specific gene regulation: Epigenetics and non-coding RNAs in inner ear development and regeneration. Semin Cell Dev Biol 2017; 65:69-79. [PMID: 27836639 PMCID: PMC5512292 DOI: 10.1016/j.semcdb.2016.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/14/2016] [Accepted: 11/03/2016] [Indexed: 12/12/2022]
Abstract
The vertebrate inner ear houses highly specialized sensory organs, tuned to detect and encode sound, head motion and gravity. Gene expression programs under the control of transcription factors orchestrate the formation and specialization of the non-sensory inner ear labyrinth and its sensory constituents. More recently, epigenetic factors and non-coding RNAs emerged as an additional layer of gene regulation, both in inner ear development and disease. In this review, we provide an overview on how epigenetic modifications and non-coding RNAs, in particular microRNAs (miRNAs), influence gene expression and summarize recent discoveries that highlight their critical role in the proper formation of the inner ear labyrinth and its sensory organs. Finally, we discuss recent insights into how epigenetic factors and miRNAs may facilitate, or in the case of mammals, restrict inner ear sensory hair cell regeneration.
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Affiliation(s)
- Angelika Doetzlhofer
- The Solomon H. Snyder Department of Neuroscience, the Center for Sensory Biology, the Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.
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18
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CT findings of the temporal bone in CHARGE syndrome: aspects of importance in cochlear implant surgery. Eur Arch Otorhinolaryngol 2016; 273:4225-4240. [PMID: 27324890 PMCID: PMC5104824 DOI: 10.1007/s00405-016-4141-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 06/11/2016] [Indexed: 11/23/2022]
Abstract
To provide an overview of anomalies of the temporal bone in CHARGE syndrome relevant to cochlear implantation (CI), anatomical structures of the temporal bone and the respective genotypes were analysed. In this retrospective study, 42 CTs of the temporal bone of 42 patients with CHARGE syndrome were reviewed in consensus by two head-and-neck radiologists and two otological surgeons. Anatomical structures of the temporal bone were evaluated and correlated with genetic data. Abnormalities that might affect CI surgery were seen, such as a vascular structure, a petrosquamosal sinus (13 %), an underdeveloped mastoid (8 %) and an aberrant course of the facial nerve crossing the round window (9 %) and/or the promontory (18 %). The appearance of the inner ear varied widely: in 77 % of patients all semicircular canals were absent and the cochlea varied from normal to hypoplastic. A stenotic cochlear aperture was observed in 37 %. The middle ear was often affected with a stenotic round (14 %) or oval window (71 %). More anomalies were observed in patients with truncating mutations than with non-truncating mutations. Temporal bone findings in CHARGE syndrome vary widely. Vascular variants, aberrant route of the facial nerve, an underdeveloped mastoid, aplasia of the semicircular canals, and stenotic round window may complicate cochlear implantation.
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19
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Gage PJ, Hurd EA, Martin DM. Mouse Models for the Dissection of CHD7 Functions in Eye Development and the Molecular Basis for Ocular Defects in CHARGE Syndrome. Invest Ophthalmol Vis Sci 2016; 56:7923-30. [PMID: 26670829 DOI: 10.1167/iovs.15-18069] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE CHARGE syndrome (Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital and/or urinary tract abnormalities, and Ear abnormalities and deafness) is the second-leading cause of deaf-blindness after Usher syndrome. Heterozygous mutations in CHD7 cause CHARGE syndrome in 70% to 90% of patients. We tested the hypothesis that tissue-specific mutant mice provide models for molecularly dissecting CHD7 functions during eye development. METHODS The conditional Chd7flox allele was mated together with tissue-specific Cre transgenes. Immunohistochemistry was used to determine the normal CHD7 pattern in the early eye primordia and to assess Chd7 mutants for expression of region-specific protein markers. RESULTS CHD7 is present in the neural ectoderm and surface ectoderm of the eye. Deletion from neural and surface ectoderm results in severely dysmorphic eyes generally lacking recognizable optic cup structures and small lenses. Deletion from the neural ectoderm results in similar defects. Deletion from the surface ectoderm results in eyes with smaller lenses. Lens tissue and the major subdivisions of the neural ectoderm are present following conditional deletion of Chd7 from the neural ectoderm. Closure of the optic fissure depends on the Chd7 gene dose within the neural ectoderm. CONCLUSIONS Eye development requires CHD7 in multiple embryonic tissues. Lens development requires CHD7 in the surface ectoderm, whereas optic cup and stalk morphogenesis require CHD7 in the neural ectoderm. CHD7 is not absolutely required for specification of the major subdivisions within the neural ectoderm. As in humans, normal eye development in mice is sensitive to Chd7 haploinsufficiency. These data indicate the Chd7 mutant mice are models for determining the molecular etiology of ocular defects in CHARGE syndrome.
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Affiliation(s)
- Philip J Gage
- Department of Ophthalmology and Visual Science, University of Michigan Medical School, Ann Arbor, Michigan, United States 2Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Elizabeth A Hurd
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Donna M Martin
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan, United States 4Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, United States
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20
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Abstract
OBJECTIVE To determine whether patients with semicircular canal dysplasia have mutations in CHD7. BACKGROUND CHARGE syndrome is a nonrandom clustering of congenital anomalies, including ocular coloboma, heart defects, choanal atresia or stenosis, retarded growth and development, genital hypoplasia, and inner and outer ear anomalies including deafness. Semicircular canal dysplasia has been included as a major diagnostic criterion for CHARGE syndrome. Mutations in the gene CHD7 on chromosome 8q12.1 are a major cause of CHARGE syndrome, but the extent to which patients with semicircular canal dysplasia have CHD7 mutations is not fully understood. STUDY DESIGN Cross-sectional analysis of CHD7 in 12 patients with semicircular canal dysplasia and variable clinical features of CHARGE syndrome. RESULTS We identified 6 CHD7 mutations, 5 of which occurred in patients who fulfilled Verloes' diagnostic criteria for typical CHARGE syndrome, and three of which were previously unreported. Of the 3 remaining CHD7 mutation-positive patients, one had atypical CHARGE by diagnostic criteria. Four MRI records were available, which revealed 2 patients with cochlear nerve aplasia and 1 patient with Chiari 1 malformation. CONCLUSION These data provide additional evidence that CHD7 mutations are a significant cause of semicircular canal atresia in children with full or partial CHARGE syndrome.
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21
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Sperry ED, Hurd EA, Durham MA, Reamer EN, Stein AB, Martin DM. The chromatin remodeling protein CHD7, mutated in CHARGE syndrome, is necessary for proper craniofacial and tracheal development. Dev Dyn 2014; 243:1055-66. [PMID: 24975120 DOI: 10.1002/dvdy.24156] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/06/2014] [Accepted: 06/20/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Heterozygous mutations in the chromatin remodeling gene CHD7 cause CHARGE syndrome, a developmental disorder with variable craniofacial dysmorphisms and respiratory difficulties. The molecular etiologies of these malformations are not well understood. Homozygous Chd7 null mice die by E11, whereas Chd7(Gt/+) heterozygous null mice are a viable and excellent model of CHARGE. We explored skeletal phenotypes in Chd7(Gt/+) and Chd7 conditional knockout mice, using Foxg1-Cre to delete Chd7 (Foxg1-CKO) in the developing eye, ear, nose, pharyngeal pouch, forebrain, and gut and Wnt1-Cre (Wnt1-CKO) to delete Chd7 in migrating neural crest cells. RESULTS Foxg1-CKO mice exhibited postnatal respiratory distress and death, dysplasia of the eye, concha, and frontal bone, hypoplastic maxillary shelves and nasal epithelia, and reduced tracheal rings. Wnt1-CKO mice exhibited frontal and occipital bone dysplasia, hypoplasia of the maxillary shelves and mandible, and cleft palate. In contrast, heterozygous Chd7(Gt/+) mice had apparently normal skeletal development. CONCLUSIONS Conditional deletion of Chd7 in ectodermal and endodermal derivatives (Foxg1-Cre) or migrating neural crest cells (Wnt1-Cre) results in varied and more severe craniofacial defects than in Chd7(Gt/+) mice. These studies indicate that CHD7 has an important, dosage-dependent role in development of several different craniofacial tissues.
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Affiliation(s)
- Ethan D Sperry
- Department of Human Genetics, The University of Michigan, Ann Arbor, Michigan; The Medical School, The University of Michigan, Ann Arbor, Michigan; Medical Scientist Training Program, The University of Michigan, Ann Arbor, Michigan
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22
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Ogier JM, Carpinelli MR, Arhatari BD, Symons RCA, Kile BT, Burt RA. CHD7 deficiency in "Looper", a new mouse model of CHARGE syndrome, results in ossicle malformation, otosclerosis and hearing impairment. PLoS One 2014; 9:e97559. [PMID: 24840056 PMCID: PMC4026240 DOI: 10.1371/journal.pone.0097559] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/21/2014] [Indexed: 12/13/2022] Open
Abstract
CHARGE syndrome is a rare human disorder caused by mutations in the gene encoding chromodomain helicase DNA binding protein 7 (CHD7). Characteristics of CHARGE are varied and include developmental ear and hearing anomalies. Here we report a novel mouse model of CHD7 dysfunction, termed Looper. The Looper strain harbours a nonsense mutation (c.5690C>A, p.S1897X) within the Chd7 gene. Looper mice exhibit many of the clinical features of the human syndrome, consistent with previously reported CHARGE models, including growth retardation, facial asymmetry, vestibular defects, eye anomalies, hyperactivity, ossicle malformation, hearing loss and vestibular dysfunction. Looper mice display an otosclerosis-like fusion of the stapes footplate to the cochlear oval window and blepharoconjunctivitis but not coloboma. Looper mice are hyperactive and have vestibular dysfunction but do not display motor impairment.
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Affiliation(s)
| | - Marina R. Carpinelli
- Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- The HEARing Cooperative Research Centre, Parkville, Victoria, Australia
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Benedicta D. Arhatari
- ARC Centre of Excellence for Coherent X-ray Science, Department of Physics, La Trobe University, Bundoora, Victoria, Australia
| | - R. C. Andrew Symons
- Department of Ophthalmology, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Benjamin T. Kile
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Genetics, University of Melbourne, Parkville, Victoria, Australia
| | - Rachel A. Burt
- Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- The HEARing Cooperative Research Centre, Parkville, Victoria, Australia
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Genetics, University of Melbourne, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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23
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Liu Y, Harmelink C, Peng Y, Chen Y, Wang Q, Jiao K. CHD7 interacts with BMP R-SMADs to epigenetically regulate cardiogenesis in mice. Hum Mol Genet 2013; 23:2145-56. [PMID: 24293546 DOI: 10.1093/hmg/ddt610] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Haploinsufficiency for CHD7, an ATP-dependent nucleosome remodeling factor, is the leading cause of CHARGE syndrome. While congenital heart defects (CHDs) are major clinical features of CHARGE syndrome, affecting >75% of patients, it remains unclear whether CHD7 can directly regulate cardiogenic genes in embryos. Our complementary yeast two-hybrid and biochemical assays reveal that CHD7 is a novel interaction partner of canonical BMP signaling pathway nuclear mediators, SMAD1/5/8, in the embryonic heart. Moreover, CHD7 associates in a BMP-dependent manner with the enhancers of a critical cardiac transcription factor, Nkx2.5, that contain functional SMAD1-binding elements. Both the active epigenetic signature of Nkx2.5 regulatory elements and its proper expression in cardiomyocytes require CHD7. Finally, inactivation of Chd7 in mice impairs multiple BMP signaling-regulated cardiogenic processes. Our results thus support the model that CHD7 is recruited by SMAD1/5/8 to the enhancers of BMP-targeted cardiogenic genes to epigenetically regulate their expression. Impaired BMP activities in embryonic hearts may thus have a major contribution to CHDs in CHARGE syndrome.
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Affiliation(s)
- Yuelong Liu
- Department of Genetics and Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
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24
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Micucci JA, Layman WS, Hurd EA, Sperry ED, Frank SF, Durham MA, Swiderski DL, Skidmore JM, Scacheri PC, Raphael Y, Martin DM. CHD7 and retinoic acid signaling cooperate to regulate neural stem cell and inner ear development in mouse models of CHARGE syndrome. Hum Mol Genet 2013; 23:434-48. [PMID: 24026680 DOI: 10.1093/hmg/ddt435] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
CHARGE syndrome is a multiple congenital anomaly disorder that leads to life-threatening birth defects, such as choanal atresia and cardiac malformations as well as multiple sensory impairments, that affect hearing, vision, olfaction and balance. CHARGE is caused by heterozygous mutations in CHD7, which encodes an ATP-dependent chromatin remodeling enzyme. Identification of the mechanisms underlying neurological and sensory defects in CHARGE is a first step toward developing treatments for CHARGE individuals. Here, we used mouse models of Chd7 deficiency to explore the function of CHD7 in the development of the subventricular zone (SVZ) neural stem cell niche and inner ear, structures that are important for olfactory bulb neurogenesis and hearing and balance, respectively. We found that loss of Chd7 results in cell-autonomous proliferative, neurogenic and self-renewal defects in the perinatal and mature mouse SVZ stem cell niche. Modulation of retinoic acid (RA) signaling prevented in vivo inner ear and in vitro neural stem cell defects caused by Chd7 deficiency. Our findings demonstrate critical, cooperative roles for RA and CHD7 in SVZ neural stem cell function and inner ear development, suggesting that altered RA signaling may be an effective method for treating Chd7 deficiency.
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