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Zhuang D, Sun S, Hu Z, Xie M, Zhang Y, Yan L, Pan J, Li H. Two novel pathogenic variants in the TCOF1 found in two Chinese cases of Treacher Collins syndrome. Mol Genet Genomic Med 2024; 12:e2405. [PMID: 38444283 PMCID: PMC10915472 DOI: 10.1002/mgg3.2405] [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: 03/31/2023] [Revised: 06/21/2023] [Accepted: 02/07/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND Treacher Collins Ι syndrome (TCS1, OMIM:154500) is an autosomal dominant disease with a series of clinical manifestations such as craniofacial dysplasia including eye and ear abnormalities, small jaw deformity, cleft lip, as well as repeated respiratory tract infection and conductive hearing loss. Two cases of Treacher Collins syndrome with TCOF1(OMIM:606847) gene variations were reported in the article, with clinical characteristics, gene variants and the etiology. METHODS The clinical data of two patients with Treacher Collins syndrome caused by TCOF1 gene variation were retrospectively analyzed. The whole exome sequencing (WES) was performed to detect the pathogenic variants of TCOF1 gene in the patients, and the verification of variants were confirmed by Sanger sequencing. RESULTS Proband 1 presented with bilateral craniofacial deformities, conductive hearing loss and recurrent respiratory tract infection. Proband 2 showed bilateral craniofacial malformations with cleft palate, which harbored similar manifestations in her family. She died soon after birth due to dyspnea and feeding difficulties. WES identified two novel pathogenic variants of TCOF1 gene in two probands, each with one variant. According to the American College of Medical Genetics and Genomics, the heterozygous variation NM_001371623.1: c.877del (p. Ala293Profs*34) of TCOF1 gene was detected in Proband 1, which was evaluated as a likely pathogenic (LP) and de novo variant. Another variant found in Proband 2 was NM_001135243.1: c.1660_1661del (p. D554Qfs*3) heterozygous variation, which was evaluated as a pathogenic variation and the variant inherited from the mother. To date, the two variants have not been reported before. CONCLUSION Our study found two novel pathogenic variants of TCOF1 gene and clarified the etiology of Treacher Collins syndrome. We also enriched the phenotypic spectrum of Treacher Collins syndrome and TCOF1 gene variation spectrum in the Chinese population, and provided the basis for clinical diagnosis, treatment and genetic counseling.
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Affiliation(s)
- Dan‐Yan Zhuang
- The Central Laboratory of Birth Defects Prevention and ControlWomen and Children's Hospital of Ningbo UniversityNingboZhejiangChina
| | - Shu‐Ni Sun
- Department of NeonatologyWomen and Children’ s Hospital of Ningbo UniversityNingboZhejiangChina
| | - Zhuo‐Jie Hu
- Department of Child Health CareWomen and Children's Hospital of Ningbo UniversityNingboZhejiangChina
| | - Min Xie
- The Central Laboratory of Birth Defects Prevention and ControlWomen and Children's Hospital of Ningbo UniversityNingboZhejiangChina
| | - Yu‐Xin Zhang
- The Central Laboratory of Birth Defects Prevention and ControlWomen and Children's Hospital of Ningbo UniversityNingboZhejiangChina
| | - Lu‐Lu Yan
- The Central Laboratory of Birth Defects Prevention and ControlWomen and Children's Hospital of Ningbo UniversityNingboZhejiangChina
| | - Jie‐Wen Pan
- The Central Laboratory of Birth Defects Prevention and ControlWomen and Children's Hospital of Ningbo UniversityNingboZhejiangChina
| | - Hai‐bo Li
- The Central Laboratory of Birth Defects Prevention and ControlWomen and Children's Hospital of Ningbo UniversityNingboZhejiangChina
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Dinwoodie OM, Tucker AS, Fons JM. Tracking cell layer contribution during repair of the tympanic membrane. Dis Model Mech 2024; 17:dmm050466. [PMID: 38390727 PMCID: PMC10985735 DOI: 10.1242/dmm.050466] [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: 08/17/2023] [Accepted: 02/17/2024] [Indexed: 02/24/2024] Open
Abstract
The tympanic membrane (i.e. eardrum) sits at the interface between the middle and external ear. The tympanic membrane is composed of three layers: an outer ectoderm-derived layer, a middle neural crest-derived fibroblast layer with contribution from the mesoderm-derived vasculature, and an inner endoderm-derived mucosal layer. These layers form a thin sandwich that is often perforated following trauma, pressure changes or middle ear inflammation. During healing, cells need to bridge the perforation in the absence of an initial scaffold. Here, we assessed the contribution, timing and interaction of the different layers during membrane repair by using markers and reporter mice. We showed that the ectodermal layer is retracted after perforation, before proliferating away from the wound edge, with keratin 5 basal cells migrating over the hole to bridge the gap. The mesenchymal and mucosal layers then used this scaffold to complete the repair, followed by advancement of the vasculature. Finally, differentiation of the epithelium led to formation of a scab. Our results reveal the dynamics and interconnections between the embryonic germ layers during repair and highlight how defects might occur.
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Affiliation(s)
- Olivia M. Dinwoodie
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
| | - Abigail S. Tucker
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
| | - Juan M. Fons
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
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Chen X, Ma J, Zhang T. Genetics and Epigenetics in the Genesis and Development of Microtia. J Craniofac Surg 2024; 35:00001665-990000000-01343. [PMID: 38345940 PMCID: PMC11045557 DOI: 10.1097/scs.0000000000010004] [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: 07/24/2023] [Accepted: 12/03/2023] [Indexed: 04/28/2024] Open
Abstract
Microtia is a congenital malformation of the external and middle ear associated with varying degrees of severity that range from mild structural abnormalities to the absence of the external ear and auditory canal. Globally, it is the second most common congenital craniofacial malformation and is typically caused by inherited defects, external factors, or the interaction between genes and external factors. Epigenetics notably represents a bridge between genetics and the environment. This review has devoted attention to the current proceedings of the genetics and epigenetics of microtia and related syndromes.
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Affiliation(s)
- Xin Chen
- Department of Facial Plastic and Reconstructive Surgery, ENT Institute, Eye & ENT Hospital, Fudan University
| | - Jing Ma
- Department of Facial Plastic and Reconstructive Surgery, ENT Institute, Eye & ENT Hospital, Fudan University
| | - Tianyu Zhang
- Department of Facial Plastic and Reconstructive Surgery, ENT Institute, Eye & ENT Hospital, Fudan University
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
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Nguyen TN, Yoo SY, Tangchang W, Lee JY, Son HY, Park JS. Sustained delivery of triamcinolone acetonide from a thermosensitive microemulsion gel system for the treatment of sensorineural hearing loss. Drug Deliv 2023; 30:2242003. [PMID: 37537864 PMCID: PMC10405762 DOI: 10.1080/10717544.2023.2242003] [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: 08/16/2022] [Revised: 04/17/2023] [Accepted: 07/03/2023] [Indexed: 08/05/2023] Open
Abstract
Intratympanic administration for the delivery of steroids has been extensively studied but limited because of low permeability of the drug through the row window membrane. Here, to effectively deliver poorly soluble triamcinolone acetonide (TA), microemulsions (ME) were prepared from Capmul MCM (oil), Cremophor RH40 (surfactant), and tetraglycol (cosurfactant) based on solubility studies, emulsifying ability test, and pseudoternary phase diagrams. Microemulsion gel (MEG) was prepared by mixing TA-ME with a poloxamer hydrogel base. The physicochemical properties of ME and MEG formulations were characterized, and the toxicity and oto-protective effectiveness were evaluated in vitro and in vivo. The ME-3 formulation showed a small droplet size (16.5 ± 0.2 nm), narrow PDI (0.067 ± 0.041), and enhanced TA solubility (2619.7 ± 57.6 μg/g). The optimized MEG demonstrated temperature-dependent gelation with a gelation time of 208 ± 10 sec at 37 °C. Slow degradation of the gel matrix sustained release of TA from MEG compared to the ME formulation. Both TA-ME and TA-MEG were found to be nontoxic to NIH3T3 cells at the test concentrations (0 to 5 µg/mL), and biocompatible after intratympanic administration to mice. The incorporation of ME into thermosensitive hydrogels prolonged retention of TA at the site of administration until 6 days. As a consequence, the enhanced drug absorption into the cochlea in TA-MEG group (approximately 2 times higher than other groups) protected hair cells, spiral ganglion neurons, and stria vascular cells from cisplatin-induced damage. Therefore, this injectable TA-loaded MEG is an effective and safe vehicle for the sustained delivery of triamcinolone acetonide into the inner ear.
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Affiliation(s)
- Thu Nhan Nguyen
- College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
| | - So-Yeol Yoo
- College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
| | - Warisraporn Tangchang
- College of Veterinary Medicine, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
| | - Jae-Young Lee
- College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
| | - Hwa-Young Son
- College of Veterinary Medicine, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
| | - Jeong-Sook Park
- College of Pharmacy, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
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5
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Sun P, Gu L, Yu Q, Luan F. Pathogenic Genes for Congenital Microtia: A Bioinformatics Analysis. J Craniofac Surg 2023; 34:2560-2562. [PMID: 37643078 DOI: 10.1097/scs.0000000000009620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 06/20/2023] [Indexed: 08/31/2023] Open
Abstract
OBJECTIVE The purpose of this study is to accurately find the pathogenic genes of congenital microtia, so as to lay a theoretical foundation for genetic screening, diagnosis, and gene therapy of congenital microtia in the further stage. METHODS In this study, the authors used public data from the Mouse Genome Informatics database. The authors used the String database ( https://string-db.org/ ) to construct the Protein-Protein Interaction network. Then Gene Ontology classification and Kyoto Encyclopedia of Genes and Genomes pathway analysis were performed for the pathogenic genes. RESULTS The authors searched the Mouse Genome Informatics database and found 84 pathogenic genes of congenital microtia. The Protein-Protein Interaction network for pathogenic genes was constructed, which contained 81 nodes and 148 lines with MCM5, CDT1, POLA1, CDC45, CDC6, EFTUD2, ORC1, ORC4, ORC6, and TCOF1 . The authors conducted a Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis on pathogenic genes, and the results showed that pathogenic genes were involved in O-mannan biosynthesis, cell cycle, RNA polymerase, and other signaling pathways. CONCLUSIONS The authors' results indicated that the occurrence of congenital microtia is attributed to a variety of genes. Furthermore, the interactions of pathogenic genes were further elucidated by using a bioinformatics approach. This study will help to reveal the pathogenesis of congenital microtia and lay the foundation for accurate diagnosis and treatment of congenital microtia in the future.
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Affiliation(s)
- Pengfei Sun
- Department of Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
| | - Luosha Gu
- Department of Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
| | - Qian Yu
- Department of Dermatologic Surgery, Shandong Provincial Hospital for Skin Disease & Shandong Provincial Institute of Dermatology and Venereology, Shandong First Medial University & Shandong Academy of Medical Sciences, Shandong
| | - Fang Luan
- Department of Plastic Surgery, Zibo Central Hospital, Shandong, China
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Fons JM, Milmoe NJ, Dack MRG, Joshi L, Thompson H, Tucker AS. The interconnected relationships between middle ear bulla size, cavitation defects, and chronic otitis media revealed in a syndromic mouse model. Front Genet 2022; 13:933416. [PMID: 36299576 PMCID: PMC9590451 DOI: 10.3389/fgene.2022.933416] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
High incidence of chronic otitis media is associated with human craniofacial syndromes, suggesting that defects in the formation of the middle ear and associated structures can have a knock-on effect on the susceptibility to middle ear inflammation. Patients with branchio-oto-renal (BOR) syndrome have several defects in the ear leading to both sensorineural and conductive hearing loss, including otitis media. 40% of BOR syndrome cases are due to Eya1 haploinsufficiency, with mouse models affecting Eya1, mimicking many of the defects found in patients. Here, we characterize the onset, consequences, and underlying causes of chronic otitis media in Eya1 heterozygous mice. Cavitation defects were evident in these mice from postnatal day (P)11 onwards, with mesenchyme around the promontory and attic regions of the middle ear space. This mesenchyme was still prominent in adult Eya1 heterozygous mice, while the wild-type littermates had fully aerated ears from P14 onwards. MicroCT analysis highlighted a significantly smaller bulla, confirming the link between bulla size defects and the ability of the mesenchyme to retract successfully. Otitis media was observed from P14, often presenting unilaterally, resulting in hyperplasia of the middle ear mucosa, expansion of secretory cells, defects in the motile cilia, and changes in basal epithelial cell markers. A high incidence of otitis media was identified in older mice but only associated with ears with retained mesenchyme. To understand the impact of the environment, the mouse line was rederived onto a super-clean environment. Cavitation defects were still evident at early stages, but these generally resolved over time, and importantly, no signs of otitis media were observed at 6 weeks. In conclusion, we show that a small bulla size is closely linked to defects in cavitation and the presence of retained mesenchyme. A delay in retraction of the mesenchyme predates the onset of otitis media, making the ears susceptible to its development. Early exposure to OM appears to exacerbate the cavitation defect, with mesenchyme evident in the middle ear throughout the animal’s life. This highlights that permanent damage to the middle ear can arise as a consequence of the early onset of OM.
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Azar A, Bhutta MF, Del-Pozo J, Milne E, Cheeseman M. Trans-cortical vessels in the mouse temporal bulla bone are a means to recruit myeloid cells in chronic otitis media and limit peripheral leukogram changes. Front Genet 2022; 13:985214. [PMID: 36246635 PMCID: PMC9555619 DOI: 10.3389/fgene.2022.985214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Chronic otitis media, inflammation of the middle ear, is a sequel to acute otitis media in ∼8% of children. Chronic otitis media with effusion is the most common cause of childhood deafness and is characterised by effusion of white blood cells into the auditory bulla cavity. Skull flat bones have trans-cortical vessels which are responsible for the majority of blood flow in and out of the bone. In experimental models of stroke and aseptic meningitis there is preferential recruitment of myeloid cells (neutrophils and monocytes) from the marrow in skull flat bones. We report trans-cortical vessels in the mouse temporal bone connect to the bulla mucosal vasculature and potentially represent a means to recruit myeloid cells directly into the inflamed bulla. The mutant mouse strains Junbo (MecomJbo/+) and Jeff (Fbxo11Jf/+) develop chronic otitis spontaneously; MecomJbo/+ mice have highly cellular neutrophil (90%) rich bulla exudates whereas Fbxo11Jf/+ mice have low cellularity serous effusions (5% neutrophils) indicating differing demand for neutrophil recruitment. However we found peripheral leukograms of MecomJbo/+ and Fbxo11Jf/+ mice are similar to their respective wild-type littermate controls with healthy bullae and infer preferential mobilization of myeloid cells from temporal bulla bone marrow may mitigate the need for a systemic inflammatory reaction. The cytokines, chemokines and haematopoietic factors found in the inflamed bulla represent candidate signalling molecules for myeloid cell mobilization from temporal bone marrow. The density of white blood cells in the bulla cavity is positively correlated with extent of mucosal thickening in MecomJbo/+, Fbxo11Jf/+, and EdaTa mice and is accompanied by changes in epithelial populations and bone remodelling. In MecomJbo/+ mice there was a positive correlation between bulla cavity WBC numbers and total bacterial load. The degree of inflammation varies between contralateral bullae and between mutant mice of different ages suggesting inflammation may wax and wane and may be re-initiated by a new wave of bacterial infection. Clearance of white blood cells and inflammatory stimuli from the bulla cavity is impaired and this may create a pro-inflammatory feedback loop which further exacerbates otitis media and delays its resolution.
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Affiliation(s)
- Ali Azar
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Mahmood F. Bhutta
- Brighton and Sussex Medical School, Brighton, United Kingdom
- Department of ENT, Royal Sussex County Hospital, Brighton, United Kingdom
| | - Jorge Del-Pozo
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Elspeth Milne
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Michael Cheeseman
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- Centre for Comparative Pathology, Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- *Correspondence: Michael Cheeseman,
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Morphometric study of the human malleus during prenatal development. Int J Pediatr Otorhinolaryngol 2022; 156:111113. [PMID: 35314375 DOI: 10.1016/j.ijporl.2022.111113] [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: 01/17/2022] [Accepted: 03/15/2022] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Establish normal reference values for the human malleus during the second and third trimesters of pregnancy, and describe its growth dynamics and ossification process. METHODS Thirty spontaneously aborted human fetuses, 12-36 weeks of age, were examined. Temporal bones were obtained en bloc and processed using the skeletal clearing and staining technique. Each malleus was obtained by microdissection. Measurements of anatomical points of the malleus were performed. Ossification was recorded. Statistics were applied. RESULTS Sixty mallei were obtained. At the end of development, the following measurements were obtained in millimeters: head length, 2.87 (2.30-3.44); neck length, 1.15 (0.92-1.38); manubrium length, 4.45 (3.75-5.16); total length, 8.51 (8.02-8.99); neck width, 1.33 (0.70-1.97); manubrium width, 0.84 (0.82-0.86); and Meckel cartilage width, 0.43 (0.06-0.95). The angle of the longitudinal axis of the malleus was 160° (156-164°). The ossification process of the malleus followed a stereotyped pattern that began at week 16, at the level of the neck, with a single center that expanded to the head and then to the manubrium. Toward the end of development, only the umbo remained cartilaginous. There were no sex-based differences in human malleus size during prenatal development. From the beginning of the second trimester of pregnancy, the longitudinal axis of the malleus acquires dimensions comparable to adults. CONCLUSION The study of the malleus development provides clues that would explain some anomalies in its development, and can influence decision-making during the placement and design of prostheses in the malleus.
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Hamie L, Eid E, Khalil S, Ghaoui N, Abbas O, Hamie M, Akl PA, Kurban M. Genodermatoses with hearing impairment. J Am Acad Dermatol 2021; 85:931-944. [PMID: 34153387 DOI: 10.1016/j.jaad.2021.06.850] [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: 01/11/2021] [Revised: 03/14/2021] [Accepted: 06/15/2021] [Indexed: 10/21/2022]
Abstract
Hearing loss is a prominent feature in multiple genodermatoses. Underappreciation of auditory deficits can misdirect proper diagnosis by the treating dermatologist. This review reviews the anatomic, developmental, and embryologic aspects that characterize the ear and summarizes genodermatoses that have aberrant auditory findings. The latter are classified into neural crest, metabolic, pigmentary, craniofacial, and a miscellaneous category of disorders lacking specific cutaneous findings. The algorithms provided in this review enable treating dermatologists to better recognize and manage genodermatoses with ear involvement.
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Affiliation(s)
- Lamiaa Hamie
- Department of Dermatology, American University of Beirut Medical Centre, Beirut, Lebanon
| | - Edward Eid
- Department of Dermatology, American University of Beirut Medical Centre, Beirut, Lebanon
| | - Samar Khalil
- Department of Dermatology, American University of Beirut Medical Centre, Beirut, Lebanon
| | - Nohra Ghaoui
- Department of Internal Medicine, American University of Beirut Medical Centre, Beirut, Lebanon
| | - Ossama Abbas
- Department of Dermatology, American University of Beirut Medical Centre, Beirut, Lebanon
| | | | | | - Mazen Kurban
- Department of Dermatology, American University of Beirut Medical Centre, Beirut, Lebanon; Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon; Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
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Milmoe NJ, Tucker AS. Craniofacial transitions: the role of EMT and MET during head development. Development 2021; 148:148/4/dev196030. [DOI: 10.1242/dev.196030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ABSTRACT
Within the developing head, tissues undergo cell-fate transitions to shape the forming structures. This starts with the neural crest, which undergoes epithelial-to-mesenchymal transition (EMT) to form, amongst other tissues, many of the skeletal tissues of the head. In the eye and ear, these neural crest cells then transform back into an epithelium, via mesenchymal-to-epithelial transition (MET), highlighting the flexibility of this population. Elsewhere in the head, the epithelium loses its integrity and transforms into mesenchyme. Here, we review these craniofacial transitions, looking at why they happen, the factors that trigger them, and the cell and molecular changes they involve. We also discuss the consequences of aberrant EMT and MET in the head.
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Affiliation(s)
- Natalie J. Milmoe
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
| | - Abigail S. Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
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Pan Z, Xu H, Chen B, Tian Y, Zhang L, Zhang S, Liu D, Liu H, Li R, Hu X, Guan J, Tang W, Lu W. Treacher Collins syndrome: Clinical report and retrospective analysis of Chinese patients. Mol Genet Genomic Med 2020; 9:e1573. [PMID: 33332773 PMCID: PMC8077114 DOI: 10.1002/mgg3.1573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 01/07/2023] Open
Abstract
Background Treacher Collins syndrome‐1 (TCS1; OMIM# 154500) is a rare autosomal dominant disease that is defined by congenital craniofacial dysplasia. Here, we report four sporadic and one familial case of TCS1 in Chinese patients with clinical features presenting as hypoplasia of the zygomatic complex and mandible, downslanting palpebral fissures, coloboma of the lower eyelids, and conductive hearing loss. Materials and Methods Audiological, radiological, and physical examinations were performed. Targeted next‐generation sequencing (NGS) was performed to examine the genetics of this disease in five probands, and Sanger sequencing was used to confirm the identified variants. A literature review discusses the pathogenesis, treatment, and prevention of TCS1. Results We identified a novel insertion of c.939_940insA (p.Gly314Argfs*35; NM_001135243.1), a novel deletion of c.1766delC (p.Pro589Leufs*7), two previously reported insertions of c.1999_2000insC (p.Arg667Profs*31) and c.4218_4219insG (p.Ser1407Valfs*23), and one previously reported deletion of c.4369_4373delAAGAA (p.Lys1457Glufs*12) in the TCOF1 gene. All five cases exhibited a degree of interfamilial and intrafamilial phenotypic variability. A review of the literature revealed no clear evidence of a genotype–phenotype correlation in TCS1. Conclusion Our results expand the variant spectrum of TCOF1 and highlight that NGS is essential for the diagnosis of TCS and that genetic counseling is beneficial for guiding prevention.
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Affiliation(s)
- Zhaoyu Pan
- Department of Otorhinolaryngology, Head and Neck Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hongen Xu
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China.,Center for Applied Precision Medicine, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bei Chen
- Department of Otorhinolaryngology, Head and Neck Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yongan Tian
- BGI College, Zhengzhou University, Zhengzhou, China.,Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Linlin Zhang
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Sen Zhang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Danhua Liu
- Center for Applied Precision Medicine, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Huanfei Liu
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Ruijun Li
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Xinxin Hu
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Jingyuan Guan
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Wenxue Tang
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China.,Center for Applied Precision Medicine, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Wei Lu
- Department of Otorhinolaryngology, Head and Neck Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Bae SH, Kwak SH, Yoo JE, Kim KM, Hyun YM, Choi JY, Jung J. Three-Dimensional Distribution of Cochlear Macrophages in the Lateral Wall of Cleared Cochlea. Clin Exp Otorhinolaryngol 2020; 14:179-184. [PMID: 32734741 PMCID: PMC8111389 DOI: 10.21053/ceo.2020.00395] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/20/2020] [Indexed: 12/26/2022] Open
Abstract
Objectives Resident macrophages are well known to be present in the cochlea, but the exact patterns thereof in spiral ligaments have not been discussed in previous studies. We sought to document the distribution of macrophages in intact cochleae using three-dimensional imaging. Methods Cochleae were obtained from C-X3-C motif chemokine receptor 1+/GFP mice, and organ clearing was performed. Three-dimensional images of cleared intact cochleae were reconstructed using two-photon microscopy. The locations of individual macrophages were investigated using 100-μm stacked images to reduce bias. Cochlear inflammation was then induced by lipopolysaccharide (LPS) inoculation into the middle ear through the tympanic membrane. Four days after inoculation, three-dimensional images were obtained. Results Macrophages were scarce in areas adjacent to the stria vascularis, particularly the area just beneath it even though many have suspected macrophages to be abundant in this area. This finding remained consistent upon LPS-induced cochlear inflammation, despite a significant increase in the number of macrophages, compared to non-treated cochlea. Conclusion Resident macrophages in spiral ligaments are scarce in areas adjacent to the stria vascularis.
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Affiliation(s)
- Seong Hoon Bae
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Sang Hyun Kwak
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Jee Eun Yoo
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Kyu Min Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Young Min Hyun
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Jae Young Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Jinsei Jung
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
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13
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Kantaputra PN, Tripuwabhrut K, Intachai W, Carlson BM, Quarto N, Ngamphiw C, Tongsima S, Sonsuwan N. Treacher Collins syndrome: A novel TCOF1 mutation and monopodial stapes. Clin Otolaryngol 2020; 45:695-702. [PMID: 32351010 DOI: 10.1111/coa.13560] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/23/2020] [Accepted: 04/27/2020] [Indexed: 01/09/2023]
Abstract
Treacher Collins syndrome (TCS: OMIM 154500) is an autosomal dominant craniofacial disorder belonging to the heterogeneous group of mandibulofacial dysostoses. OBJECTIVE To investigate four Treacher Collins syndrome patients of the Sgaw Karen family living in Thailand. METHOD Clinical examination, hearing tests, lateral cephalometric analyses, Computed tomography, whole exome sequencing and Sanger direct sequencing were performed. RESULTS All of the patients affected with Treacher Collins syndrome carried a novel TCOF1 mutation (c.4138_4142del; p.Lys1380GlufsTer12), but clinically they did not have the typical facial gestalt of Treacher Collins syndrome, which includes downward-slanting palpebral fissures, colobomas of the lower eyelids, absence of eyelashes medial to the colobomas, malformed pinnae, hypoplastic zygomatic bones and mandibular hypoplasia. Lateral cephalometric analyses identified short anterior and posterior cranial bases, and hypoplastic maxilla and mandible. Computed tomography showed fusion of malleus and incus, sclerotic mastoid, hypoplastic middle ear space with a soft tissue remnant, dehiscence of facial nerve and monopodial stapes. CONCLUSION Treacher Collins syndrome in Sgaw Karen patients has not been previously documented. This is the first report of monopodial stapes in a TCS patient who had a TCOF1 mutation. The absence of a common facial phenotype and/or the presence of monopodial stapes may be the effects of this novel TCOF1 mutation.
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Affiliation(s)
- Piranit Nik Kantaputra
- Center of Excellence in Medical Genetics Research, Chiang Mai University, Chiang Mai, Thailand.,Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.,Dentaland Clinic, Chiang Mai, Thailand
| | - Kanich Tripuwabhrut
- Division of Orthodontics, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Worrachet Intachai
- Center of Excellence in Medical Genetics Research, Chiang Mai University, Chiang Mai, Thailand
| | - Bruce M Carlson
- Department of Anatomy and Cell Biology, University of Michigan, Ann Arbor, MI, USA
| | - Natalina Quarto
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Chumpol Ngamphiw
- National Biobank of Thailand, National Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand Science Park, Pathum Thani, Thailand
| | - Sissades Tongsima
- National Biobank of Thailand, National Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand Science Park, Pathum Thani, Thailand
| | - Nuntigar Sonsuwan
- Department of Otolaryngology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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14
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Tahara R, Larsson HCE. Development of the paratympanic pneumatic system of Japanese quail. J Morphol 2019; 280:1492-1529. [DOI: 10.1002/jmor.21045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/28/2019] [Accepted: 07/05/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Rui Tahara
- Redpath MuseumMcGill University Montreal Quebec Canada
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15
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Li X, Su Y, Huang S, Gao B, Zhang D, Wang X, Gao Q, Pang H, Zhao Y, Yuan Y, Dai P. Genotype-phenotype variability in Chinese cases of Treacher Collins syndrome. Acta Otolaryngol 2019; 139:567-575. [PMID: 31107123 DOI: 10.1080/00016489.2019.1612530] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Background: Treacher Collins syndrome (TCS) is a clinically and genetically heterogeneous disorder of craniofacial development mainly caused by variants in TCOF1, POLR1D, and POLR1C. Objectives: This study examined the causative genes of five TCS cases. Materials and Methods: In this study, two familial cases and three sporadic cases clinically diagonsed with TCS are described. Mutational analysis in probands was performed by targeted next-generation sequencing (NGS). Mutations identified by NGS were further confirmed by Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). Results: A novel gross deletion (exons 9-13), a novel small deletion (c.381_382delAG), and two known deletions (c.4131_4135delAAAAG and c.2394_2395delAG) within TCOF1 as well as a known mutation (c.91C > T) in POLR1D were identified. These five cases exhibited high inter- and intra-familial phenotypic heterogeneity. Conclusion: This is the first report of Chinese TCS cases caused by a gross deletion within TCOF1 and mutations in POLR1D. In addition to expanding the spectrum of TCS-associated mutation in the Chinese population, our findings present the diversity of its clinical presentation. It is recommended that analyses such as NGS or MLPA capable of detecting large deletions be undertaken as a part of TCS molecular diagnosis.
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Affiliation(s)
- Xiaohong Li
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
| | - Yu Su
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
| | - Shasha Huang
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
| | - Bo Gao
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
| | - Dejun Zhang
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- Department of Otolaryngology, Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, China
| | - Xiaobin Wang
- Department of Bioinformatics, MyGenostics Inc., Beijing, China
| | - Qin Gao
- Department of Bioinformatics, MyGenostics Inc., Beijing, China
| | - Hong Pang
- Department of Genetics, Shenyang Women’s and Children’s Hospital, Shenyang, China
| | - Yan Zhao
- Department of Genetics, Shenyang Women’s and Children’s Hospital, Shenyang, China
| | - Yongyi Yuan
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
| | - Pu Dai
- Department of Otolaryngology, Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
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16
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Del-Pozo J, MacIntyre N, Azar A, Glover J, Milne E, Cheeseman M. Chronic otitis media is initiated by a bulla cavitation defect in the FBXO11 mouse model. Dis Model Mech 2019; 12:12/3/dmm038315. [PMID: 30898767 PMCID: PMC6451434 DOI: 10.1242/dmm.038315] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/25/2019] [Indexed: 12/20/2022] Open
Abstract
Auditory bulla cavitation defects are a cause of otitis media, but the normal cellular pattern of bulla mesenchyme regression and its failure are not well understood. In mice, neural-crest-derived mesenchyme occupies the bulla from embryonic day 17.5 (E17.5) to postnatal day 11 (P11) and then regresses to form the adult air-filled bulla cavity. We report that bulla mesenchyme is bordered by a single layer of non-ciliated epithelium characterized by interdigitating cells with desmosome cell junctions and a basal lamina, and by Bpifa1 gene expression and laminin staining of the basal lamina. At P11-P12, the mesenchyme shrinks: mesenchyme-associated epithelium shortens, and mesenchymal cells and extracellular matrix collagen fibrils condense, culminating in the formation of cochlea promontory mucosa bordered by compact non-ciliated epithelial cells. FBXO11 is a candidate disease gene in human chronic otitis media with effusion and we report that a bulla cavitation defect initiates the pathogenesis of otitis media in the established mouse model Jeff (Fbxo11Jf/+). Persistent mesenchyme in Fbxo11Jf/+ bullae has limited mesenchymal cell condensation, fibrosis and hyperplasia of the mesenchyme-associated epithelium. Subsequent modification forms fibrous adhesions that link the mucosa and the tympanic membrane, and this is accompanied by dystrophic mineralization and accumulation of serous effusion in the bulla cavity. Mouse models of bulla cavitation defects are important because their study in humans is limited to post-mortem samples. This work indicates new diagnostic criteria for this otitis media aetiology in humans, and the prospects of studying the molecular mechanisms of murine bulla cavitation in organ culture. Summary: FBXO11 is a candidate disease gene for otitis media in humans and the authors report that a bulla cavitation defect initiates otitis media in the Fbxo11Jf/+ mouse model.
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Affiliation(s)
- Jorge Del-Pozo
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Neil MacIntyre
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Ali Azar
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - James Glover
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Elspeth Milne
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Michael Cheeseman
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK .,Centre for Comparative Pathology & Division of Pathology, University of Edinburgh, Institute of Genetics & Molecular Medicine, Crewe Road, Edinburgh EH4 2XR, UK
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17
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Genetic variation in thyroid folliculogenesis influences susceptibility to hypothyroidism-induced hearing impairment. Mamm Genome 2019; 30:5-22. [PMID: 30778664 DOI: 10.1007/s00335-019-09792-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 01/09/2019] [Indexed: 10/27/2022]
Abstract
Maternal and fetal sources of thyroid hormone are important for the development of many organ systems. Thyroid hormone deficiency causes variable intellectual disability and hearing impairment in mouse and man, but the basis for this variation is not clear. To explore this variation, we studied two thyroid hormone-deficient mouse mutants with mutations in pituitary-specific transcription factors, POU1F1 and PROP1, that render them unable to produce thyroid stimulating hormone. DW/J-Pou1f1dw/dw mice have profound deafness and both neurosensory and conductive hearing impairment, while DF/B-Prop1df/df mice have modest elevations in hearing thresholds consistent with developmental delay, eventually achieving normal hearing ability. The thyroid glands of Pou1f1 mutants are more severely affected than those of Prop1df/df mice, and they produce less thyroglobulin during the neonatal period critical for establishing hearing. We previously crossed DW/J-Pou1f1dw/+ and Cast/Ei mice and mapped a major locus on Chromosome 2 that protects against hypothyroidism-induced hearing impairment in Pou1f1dw/dw mice: modifier of dw hearing (Mdwh). Here we refine the location of Mdwh by genotyping 196 animals with 876 informative SNPs, and we conduct novel mapping with a DW/J-Pou1f1dw/+ and 129/P2 cross that reveals 129/P2 mice also have a protective Mdwh locus. Using DNA sequencing of DW/J and DF/B strains, we determined that the genes important for thyroid gland function within Mdwh vary in amino acid sequence between strains that are susceptible or resistant to hypothyroidism-induced hearing impairment. These results suggest that the variable effects of congenital hypothyroidism on the development of hearing ability are attributable to genetic variation in postnatal thyroid gland folliculogenesis and function.
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18
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Ritter KE, Martin DM. Neural crest contributions to the ear: Implications for congenital hearing disorders. Hear Res 2018; 376:22-32. [PMID: 30455064 DOI: 10.1016/j.heares.2018.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/30/2018] [Accepted: 11/12/2018] [Indexed: 12/16/2022]
Abstract
Congenital hearing disorders affect millions of children worldwide and can significantly impact acquisition of speech and language. Efforts to identify the developmental genetic etiologies of conductive and sensorineural hearing losses have revealed critical roles for cranial neural crest cells (NCCs) in ear development. Cranial NCCs contribute to all portions of the ear, and defects in neural crest development can lead to neurocristopathies associated with profound hearing loss. The molecular mechanisms governing the development of neural crest derivatives within the ear are partially understood, but many questions remain. In this review, we describe recent advancements in determining neural crest contributions to the ear, how they inform our understanding of neurocristopathies, and highlight new avenues for further research using bioinformatic approaches.
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Affiliation(s)
- K Elaine Ritter
- Department of Pediatrics, The University of Michigan Medical School, Ann Arbor, MI, USA
| | - Donna M Martin
- Department of Pediatrics, The University of Michigan Medical School, Ann Arbor, MI, USA; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA.
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19
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The adhesion molecule cadherin 11 is essential for acquisition of normal hearing ability through middle ear development in the mouse. J Transl Med 2018; 98:1364-1374. [PMID: 29967341 DOI: 10.1038/s41374-018-0083-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 04/07/2018] [Accepted: 04/24/2018] [Indexed: 01/29/2023] Open
Abstract
Cadherin 11 (Cdh11), a member of the cadherin adhesion molecule family, is expressed in various regions of the brain as well as the head and ear. To gain further insights into the roles of Cdh11 in the development of the ear, we performed behavioral tests using Cdh11 knockout (KO) mice. KO mice showed reduced acoustic startle responses and increased thresholds for auditory brainstem responses, indicating moderate hearing loss. The auditory bulla volume and ratio of air-filled to non-air-filled space in the middle ear cavity were reduced in KO mice, potentially causing conductive hearing loss. Furthermore, residual mesenchymal and inflammatory cells were observed in the middle ear cavity of KO mice. Cdh11 was expressed in developing mesenchymal cells just before the start of cavitation, indicating that Cdh11 may be directly involved in middle ear cavitation. Since the auditory bulla is derived from the neural crest, the regulation of neural crest-derived cells by Cdh11 may be responsible for structural development. This mutant mouse may be a promising animal model for elucidating the causes of conductive hearing loss and otitis media.
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20
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Rigueur D, Roberts RR, Bobzin L, Merrill AE. A requirement for Fgfr2 in middle ear development. Genesis 2018; 57:e23252. [PMID: 30253032 DOI: 10.1002/dvg.23252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022]
Abstract
The skeletal structure of the mammalian middle ear, which is composed of three endochondral ossicles suspended within a membranous air-filled capsule, plays a critical role in conducting sound. Gene mutations that alter skeletal development in the middle ear result in auditory impairment. Mutations in fibroblast growth factor receptor 2 (FGFR2), an important regulator of endochondral and intramembranous bone formation, cause a spectrum of congenital skeletal disorders featuring conductive hearing loss. Although the middle ear malformations in multiple FGFR2 gain-of-function disorders are clinically characterized, those in the FGFR2 loss-of-function disorder lacrimo-auriculo-dento-digital (LADD) syndrome are relatively undescribed. To better understand conductive hearing loss in LADD, we examined the middle ear skeleton of mice with conditional loss of Fgfr2. We find that decreased auditory function in Fgfr2 mutant mice correlates with hypoplasia of the auditory bulla and ectopic bone growth at sites of tendon/ligament attachment. We show that ectopic bone associated with the intra-articular ligaments of the incudomalleal joint is derived from Scx-expressing cells and preceded by decreased expression of the joint progenitor marker Gdf5. Together, these results identify a role for Fgfr2 in development of the middle ear skeletal tissues and suggest potential causes for conductive hearing loss in LADD syndrome.
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Affiliation(s)
- Diana Rigueur
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Ryan R Roberts
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Lauren Bobzin
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Amy E Merrill
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
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21
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Tucker AS, Dyer CJ, Fons Romero JM, Teshima THN, Fuchs JC, Thompson H. Mapping the distribution of stem/progenitor cells across the mouse middle ear during homeostasis and inflammation. Development 2018; 145:dev.154393. [PMID: 29217752 DOI: 10.1242/dev.154393] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 11/27/2017] [Indexed: 12/21/2022]
Abstract
The middle ear epithelium is derived from neural crest and endoderm, which line distinct regions of the middle ear cavity. Here, we investigate the distribution of putative stem cell markers in the middle ear, combined with an analysis of the location of label-retaining cells (LRCs) to create a map of the middle ear mucosa. We show that proliferating cells and LRCs were associated with specific regions of the ear epithelium, concentrated in the hypotympanum at the base of the auditory bulla and around the ear drum. Sox2 was widely expressed in the endodermally derived ciliated pseudostratified epithelium of the hypotympanum. This part of the middle ear showed high levels of Wnt activity, as indicated by the expression of Axin2, a readout of Wnt signalling. Keratin 5 showed a more restricted expression within the basal cells of this region, with very little overlap between the Sox2- and keratin 5-positive epithelium, indicating that these genes mark distinct populations. Little expression of Sox2 or keratin 5 was observed in the neural crest-derived middle ear epithelium that lined the promontory, except in cases of otitis media when this epithelium underwent hyperplasia. This study lays the foundation for furthering our understanding of homeostasis and repair in the middle ear.
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Affiliation(s)
- Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Carlene J Dyer
- Centre for Craniofacial and Regenerative Biology, Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Juan M Fons Romero
- Centre for Craniofacial and Regenerative Biology, Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Tathyane H N Teshima
- Centre for Craniofacial and Regenerative Biology, Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK.,Department of Stomatology, School of Dentistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Jennifer C Fuchs
- Centre for Craniofacial and Regenerative Biology, Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Hannah Thompson
- Centre for Craniofacial and Regenerative Biology, Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
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22
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Tucker AS. Major evolutionary transitions and innovations: the tympanic middle ear. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2015.0483. [PMID: 27994124 PMCID: PMC5182415 DOI: 10.1098/rstb.2015.0483] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2016] [Indexed: 01/08/2023] Open
Abstract
One of the most amazing transitions and innovations during the evolution of mammals was the formation of a novel jaw joint and the incorporation of the original jaw joint into the middle ear to create the unique mammalian three bone/ossicle ear. In this review, we look at the key steps that led to this change and other unusual features of the middle ear and how developmental biology has been providing an understanding of the mechanisms involved. This starts with an overview of the tympanic (air-filled) middle ear, and how the ear drum (tympanic membrane) and the cavity itself form during development in amniotes. This is followed by an investigation of how the ear is connected to the pharynx and the relationship of the ear to the bony bulla in which it sits. Finally, the novel mammalian jaw joint and versatile dentary bone will be discussed with respect to evolution of the mammalian middle ear.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'.
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Affiliation(s)
- Abigail S Tucker
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Floor 27 Guy's Hospital, London Bridge, London SE1 9RT, UK
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23
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Terrazas K, Dixon J, Trainor PA, Dixon MJ. Rare syndromes of the head and face: mandibulofacial and acrofacial dysostoses. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2017; 6:10.1002/wdev.263. [PMID: 28186364 PMCID: PMC5400673 DOI: 10.1002/wdev.263] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/26/2016] [Accepted: 11/21/2016] [Indexed: 12/13/2022]
Abstract
Craniofacial anomalies account for approximately one-third of all congenital birth defects reflecting the complexity of head and facial development. Craniofacial development is dependent upon a multipotent, migratory population of neural crest cells, which generate most of the bone and cartilage of the head and face. In this review, we discuss advances in our understanding of the pathogenesis of a specific array of craniofacial anomalies, termed facial dysostoses, which can be subdivided into mandibulofacial dysostosis, which present with craniofacial defects only, and acrofacial dysostosis, which encompasses both craniofacial and limb anomalies. In particular, we focus on Treacher Collins syndrome, Acrofacial Dysostosis-Cincinnati Type as well as Nager and Miller syndromes, and animal models that provide new insights into the molecular and cellular basis of these congenital syndromes. We emphasize the etiologic and pathogenetic similarities between these birth defects, specifically their unique deficiencies in global processes including ribosome biogenesis, DNA damage repair, and pre-mRNA splicing, all of which affect neural crest cell development and result in similar tissue-specific defects. WIREs Dev Biol 2017, 6:e263. doi: 10.1002/wdev.263 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Karla Terrazas
- Stowers Institute for Medical Research, 1000 E. 50th Street Kansas City, MO 64110, USA
| | - Jill Dixon
- Division of Dentistry, Faculty of Biology, Medicine & Health, Michael Smith Building, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Paul A Trainor
- Stowers Institute for Medical Research, 1000 E. 50th Street Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Michael J Dixon
- Division of Dentistry, Faculty of Biology, Medicine & Health, Michael Smith Building, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
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24
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Chhan D, McKinnon ML, Rosowski JJ. Identification of induced and naturally occurring conductive hearing loss in mice using bone conduction. Hear Res 2017; 346:45-54. [PMID: 28167132 DOI: 10.1016/j.heares.2017.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/04/2017] [Accepted: 02/01/2017] [Indexed: 01/05/2023]
Abstract
While many mouse models of hearing loss have been described, a significant fraction of the genetic defects in these models affect both the inner ear and middle ears. A common method used to separate inner-ear (sensory-neural) from middle-ear (conductive) pathologies in the hearing clinic is the combination of air-conduction and bone-conduction audiometry. In this report, we investigate the use of air- and bone-conducted evoked auditory brainstem responses to perform a similar separation in mice. We describe a technique by which we stimulate the mouse ear both acoustically and via whole-head vibration. We investigate the sensitivity of this technique to conductive hearing loss by introducing middle-ear lesions in normal hearing mice. We also use the technique to investigate the presence of an age-related conductive hearing loss in a common mouse model of presbycusis, the BALB/c mouse.
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Affiliation(s)
- David Chhan
- Army Research Lab, Aberdeen Proving Ground, MD, USA.
| | - Melissa L McKinnon
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA.
| | - John J Rosowski
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA; Department of Otolaryngology, Harvard Medical School, Boston, MA, USA.
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25
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Sakamoto A, Kuroda Y, Kanzaki S, Matsuo K. Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis. J Vis Exp 2017. [PMID: 28117786 PMCID: PMC5408703 DOI: 10.3791/55054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In most mammals, auditory ossicles in the middle ear, including the malleus, incus and stapes, are the smallest bones. In mice, a bony structure called the auditory bulla houses the ossicles, whereas the auditory capsule encloses the inner ear, namely the cochlea and semicircular canals. Murine ossicles are essential for hearing and thus of great interest to researchers in the field of otolaryngology, but their metabolism, development, and evolution are highly relevant to other fields. Altered bone metabolism can affect hearing function in adult mice, and various gene-deficient mice show changes in morphogenesis of auditory ossicles in utero. Although murine auditory ossicles are tiny, their manipulation is feasible if one understands their anatomical orientation and 3D structure. Here, we describe how to dissect the auditory bulla and capsule of postnatal mice and then isolate individual ossicles by removing part of the bulla. We also discuss how to embed the bulla and capsule in different orientations to generate paraffin or frozen sections suitable for preparation of longitudinal, horizontal, or frontal sections of the malleus. Finally, we enumerate anatomical differences between mouse and human auditory ossicles. These methods would be useful in analyzing pathological, developmental and evolutionary aspects of auditory ossicles and the middle ear in mice.
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Affiliation(s)
- Ayako Sakamoto
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine
| | - Yukiko Kuroda
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine
| | - Sho Kanzaki
- Department of Otolaryngology Head and Neck Surgery, Keio University School of Medicine
| | - Koichi Matsuo
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine;
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Mutational Analysis of TCOF1, GSC, and HOXA2 in Patients With Treacher Collins Syndrome. J Craniofac Surg 2016; 27:e583-6. [PMID: 27526242 PMCID: PMC5023764 DOI: 10.1097/scs.0000000000002934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Treacher Collins syndrome is an autosomal dominant craniofacial malformation mainly caused by mutations in the TCOF1 gene. Few cases have been observed in the Chinese population. Herein, the authors report the mutational analysis of TCOF1, GSC, and HOXA2 to determine the mutational features of the 3 genes in Chinese patients with Treacher Collins syndrome. Genomic DNA of the patients and their parents was extracted from peripheral blood following a standard protocol. DNA sequencing analysis was performed on all exons and the exon-intron borders of TCOF1, GSC, and HOXA2 in addition to the 1200-bp upstream of TCOF1. Four novel single nucleotide polymorphisms were detected in TCOF1, one of which was in the promoter region. Mutations in GSC and HOXA2 were not found in the 3 patients. Our results suggest the possibility of genetic heterogeneity or different mechanisms leading to the disease. Further functional study of the alteration is necessary to obtain more definitive information.
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Abstract
The mammalian ear is a complex structure divided into three main parts: the outer; middle; and inner ear. These parts are formed from all three germ layers and neural crest cells, which have to integrate successfully in order to form a fully functioning organ of hearing. Any defect in development of the outer and middle ear leads to conductive hearing loss, while defects in the inner ear can lead to sensorineural hearing loss. This review focuses on the development of the parts of the ear involved with sound transduction into the inner ear, and the parts largely ignored in the world of hearing research: the outer and middle ear. The published data on the embryonic origin, signalling, genetic control, development and timing of the mammalian middle and outer ear are reviewed here along with new data showing the Eustachian tube cartilage is of dual embryonic origin. The embryonic origin of some of these structures has only recently been uncovered (Science, 339, 2013, 1453; Development, 140, 2013, 4386), while the molecular mechanisms controlling the growth, structure and integration of many outer and middle ear components are hardly known. The genetic analysis of outer and middle ear development is rather limited, with a small number of genes often affecting either more than one part of the ear or having only very small effects on development. This review therefore highlights the necessity for further research into the development of outer and middle ear structures, which will be important for the understanding and treatment of conductive hearing loss.
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Affiliation(s)
- Neal Anthwal
- Craniofacial Development and Stem Cell BiologyKing's College LondonLondonUK
| | - Hannah Thompson
- Craniofacial Development and Stem Cell BiologyKing's College LondonLondonUK
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28
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Abstract
The perception of our environment via sensory organs plays a crucial role in survival and evolution. Hearing, one of our most developed senses, depends on the proper function of the auditory system and plays a key role in social communication, integration, and learning ability. The ear is a composite structure, comprised of the external, middle, and inner ear. During development, the ear is formed from the integration of a number of tissues of different embryonic origin, which initiate in distinct areas of the embryo at different time points. Functional connections between the components of the hearing apparatus have to be established and maintained during development and adulthood to allow proper sound submission from the outer to the middle and inner ear. This highly organized and intimate connectivity depends on intricate spatiotemporal signaling between the various tissues that give rise to the structures of the ear. Any alterations in this chain of events can lead to the loss of integration, which can subsequently lead to conductive hearing loss, in case of outer and middle ear defects or sensorineural hearing loss, if inner ear structures are defective. This chapter aims to review the current knowledge concerning the development of the three ear compartments as well as mechanisms and signaling pathways that have been implicated in the coordination and integration process of the ear.
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Affiliation(s)
- Jennifer C Fuchs
- Department of Craniofacial Development & Stem Cell Biology, King's College London, London, United Kingdom
| | - Abigail S Tucker
- Department of Craniofacial Development & Stem Cell Biology, King's College London, London, United Kingdom.
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Fuchs JC, Linden JF, Baldini A, Tucker AS. A defect in early myogenesis causes Otitis media in two mouse models of 22q11.2 Deletion Syndrome. Hum Mol Genet 2014; 24:1869-82. [PMID: 25452432 PMCID: PMC4355021 DOI: 10.1093/hmg/ddu604] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Otitis media (OM), the inflammation of the middle ear, is the most common disease and cause for surgery in infants worldwide. Chronic Otitis media with effusion (OME) often leads to conductive hearing loss and is a common feature of a number of craniofacial syndromes, such as 22q11.2 Deletion Syndrome (22q11.2DS). OM is more common in children because the more horizontal position of the Eustachian tube (ET) in infants limits or delays clearance of middle ear effusions. Some mouse models with OM have shown alterations in the morphology and angle of the ET. Here, we present a novel mechanism in which OM is caused not by a defect in the ET itself but in the muscles that control its function. Our results show that in two mouse models of 22q11.2DS (Df1/+ and Tbx1(+/-)) presenting with bi- or unilateral OME, the fourth pharyngeal arch-derived levator veli palatini muscles were hypoplastic, which was associated with an earlier altered pattern of MyoD expression. Importantly, in mice with unilateral OME, the side with the inflammation was associated with significantly smaller muscles than the contralateral unaffected ear. Functional tests examining ET patency confirmed a reduced clearing ability in the heterozygous mice. Our findings are also of clinical relevance as targeting hypoplastic muscles might present a novel preventative measure for reducing the high rates of OM in 22q11.2DS patients.
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Affiliation(s)
- Jennifer C Fuchs
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Jennifer F Linden
- Ear Institute and Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 8XX, UK
| | - Antonio Baldini
- Institute of Genetics and Biophysics, National Research Council, and Department of Molecular Medicine and Medical Biotechnology, University Federico II, Naples 80138, Italy
| | - Abigail S Tucker
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK,
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Chen L, Dean C, Gandolfi M, Nahm E, Mattiace L, Kim AH. Dexamethasone's effect in the retrocochlear auditory centers of a noise-induced hearing loss mouse model. Otolaryngol Head Neck Surg 2014; 151:667-74. [PMID: 25113508 DOI: 10.1177/0194599814545771] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Examine prophylactic effects of dexamethasone (Dex) in retrocochlear auditory centers in a noise-induced hearing loss (NIHL) mouse model. STUDY DESIGN Prospective animal study. SETTING Academic research center. SUBJECTS AND METHODS Thirty-two mice were divided into control, untreated, saline (2 and 10 µL), and Dex (2 and 10 µL) groups. Dex was applied intratympanically (IT) prior to 110 to 120 dB noise over 6 hours. Auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) were performed at 1 day, 1 week, 1 month, and 2 months. Retrocochlear neuronal cells were labeled with FluoroGold and counted. Hair cells of the organ of Corti were labeled with fluorescein isothiocyanate-conjugated phalloidin and counted. RESULTS Auditory brainstem response thresholds of untreated NIHL, 2 and 10 µL IT saline, and 2 and 10 µL IT Dex were 21.7 ± 2.9 dB, 20 ± 0 dB, 20 ± 5 dB, 18.3 ± 2.9 dB, and 18.3 ± 2.9 dB, respectively. At 1-day post NIHL, all groups demonstrated profound hearing loss. At 2 weeks, 2 and 10 µL Dex thresholds improved to 47.5 ± 3.5 dB and 48.8 ± 18.9 dB, respectively, whereas the untreated and saline groups remained unchanged. Mean cell counts in the cochlear nucleus (CN), superior olivary complex (SOC), and lateral lemniscus (LL) of control mice were 1483 ± 190, 2807 ± 67, and 112 ± 20, respectively. After acoustic trauma, the untreated, saline, and 2 µL Dex groups yielded decreased neuronal counts in the SOC. In contrast, the 10 µL Dex group had 1883 ± 186 (CN), 2774 ± 182 (SOC), and 166 ± 18 (LL). There was sporadic hair cell loss for all traumatized groups. CONCLUSION Our NIHL mouse model demonstrated dose-dependent Dex pretreatment otoprotection against NIHL with preservation of retrocochlear auditory neurons.
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Affiliation(s)
- Leon Chen
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary, New York, New York, USA
| | - Clare Dean
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary, New York, New York, USA
| | - Michele Gandolfi
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary, New York, New York, USA
| | - Edmund Nahm
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary, New York, New York, USA
| | - Linda Mattiace
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, USA
| | - Ana H Kim
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary, New York, New York, USA Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, USA
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Armistead J, Triggs-Raine B. Diverse diseases from a ubiquitous process: the ribosomopathy paradox. FEBS Lett 2014; 588:1491-500. [PMID: 24657617 DOI: 10.1016/j.febslet.2014.03.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 03/08/2014] [Accepted: 03/12/2014] [Indexed: 01/03/2023]
Abstract
Collectively, the ribosomopathies are caused by defects in ribosome biogenesis. Although these disorders encompass deficiencies in a ubiquitous and fundamental process, the clinical manifestations are extremely variable and typically display tissue specificity. Research into this paradox has offered fascinating new insights into the role of the ribosome in the regulation of mRNA translation, cell cycle control, and signaling pathways involving TP53, MYC and mTOR. Several common features of ribosomopathies such as small stature, cancer predisposition, and hematological defects, point to how these diverse diseases may be related at a molecular level.
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Affiliation(s)
- Joy Armistead
- Department of Biochemistry and Medical Genetics, The University of Manitoba, 745 Bannatyne Ave., Winnipeg, MB R3E 0J9, Canada
| | - Barbara Triggs-Raine
- Department of Biochemistry and Medical Genetics, The University of Manitoba, 745 Bannatyne Ave., Winnipeg, MB R3E 0J9, Canada; The Manitoba Institute of Child Health, 715 McDermot Ave., Winnipeg, MB R3E 3P4, Canada.
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Fuchs JC, Zinnamon FA, Taylor RR, Ivins S, Scambler PJ, Forge A, Tucker AS, Linden JF. Hearing loss in a mouse model of 22q11.2 Deletion Syndrome. PLoS One 2013; 8:e80104. [PMID: 24244619 PMCID: PMC3828191 DOI: 10.1371/journal.pone.0080104] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/09/2013] [Indexed: 11/19/2022] Open
Abstract
22q11.2 Deletion Syndrome (22q11DS) arises from an interstitial chromosomal microdeletion encompassing at least 30 genes. This disorder is one of the most significant known cytogenetic risk factors for schizophrenia, and can also cause heart abnormalities, cognitive deficits, hearing difficulties, and a variety of other medical problems. The Df1/+ hemizygous knockout mouse, a model for human 22q11DS, recapitulates many of the deficits observed in the human syndrome including heart defects, impaired memory, and abnormal auditory sensorimotor gating. Here we show that Df1/+ mice, like human 22q11DS patients, have substantial rates of hearing loss arising from chronic middle ear infection. Auditory brainstem response (ABR) measurements revealed significant elevation of click-response thresholds in 48% of Df1/+ mice, often in only one ear. Anatomical and histological analysis of the middle ear demonstrated no gross structural abnormalities, but frequent signs of otitis media (OM, chronic inflammation of the middle ear), including excessive effusion and thickened mucosa. In mice for which both in vivo ABR thresholds and post mortem middle-ear histology were obtained, the severity of signs of OM correlated directly with the level of hearing impairment. These results suggest that abnormal auditory sensorimotor gating previously reported in mouse models of 22q11DS could arise from abnormalities in auditory processing. Furthermore, the findings indicate that Df1/+ mice are an excellent model for increased risk of OM in human 22q11DS patients. Given the frequently monaural nature of OM in Df1/+ mice, these animals could also be a powerful tool for investigating the interplay between genetic and environmental causes of OM.
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Affiliation(s)
- Jennifer C. Fuchs
- Craniofacial Development & Stem Cell Biology, King's College London, London, United Kingdom
| | | | - Ruth R. Taylor
- Ear Institute, University College London, London, United Kingdom
| | - Sarah Ivins
- Institute of Child Health, University College London, London, United Kingdom
| | - Peter J. Scambler
- Institute of Child Health, University College London, London, United Kingdom
| | - Andrew Forge
- Ear Institute, University College London, London, United Kingdom
| | - Abigail S. Tucker
- Craniofacial Development & Stem Cell Biology, King's College London, London, United Kingdom
| | - Jennifer F. Linden
- Ear Institute, University College London, London, United Kingdom
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
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33
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van Gijn DR, Tucker AS, Cobourne MT. Craniofacial development: current concepts in the molecular basis of Treacher Collins syndrome. Br J Oral Maxillofac Surg 2013; 51:384-8. [DOI: 10.1016/j.bjoms.2012.09.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 09/07/2012] [Indexed: 12/12/2022]
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35
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Developmental origin and fate of middle ear structures. Hear Res 2013; 301:19-26. [PMID: 23396272 DOI: 10.1016/j.heares.2013.01.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 11/21/2022]
Abstract
Results from developmental and phylogenetic studies have converged to facilitate insight into two important steps in vertebrate evolution: (1) the ontogenetic origin of articulating elements of the buccal skeleton, i.e., jaws, and (2) the later origins of middle ear impedance-matching systems that convey air-borne sound to the inner ear fluids. Middle ear ossicles and other skeletal elements of the viscerocranium (i.e., gill suspensory arches and jaw bones) share a common origin both phylogenetically and ontogenetically. The intention of this brief overview of middle-ear development is to emphasize the intimate connection between evolution and embryogenesis. Examples of developmental situations are discussed in which cells of different provenance, such as neural crest, mesoderm or endoderm, gather together and reciprocal interactions finally determine cell fate. Effects of targeted mutagenesis on middle ear development are described to illustrate how the alteration of molecularly-controlled morphogenetic programs led to phylogenetic modifications of skeletal development. Ontogenetic plasticity has enabled the diversification of jaw elements as well as middle ear structures during evolution. This article is part of a special issue entitled "MEMRO 2012".
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36
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Cordas EA, Ng L, Hernandez A, Kaneshige M, Cheng SY, Forrest D. Thyroid hormone receptors control developmental maturation of the middle ear and the size of the ossicular bones. Endocrinology 2012; 153:1548-60. [PMID: 22253431 PMCID: PMC3281545 DOI: 10.1210/en.2011-1834] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thyroid hormone is critical for auditory development and has well-known actions in the inner ear. However, less is known of thyroid hormone functions in the middle ear, which contains the ossicles (malleus, incus, stapes) that relay mechanical sound vibrations from the outer ear to the inner ear. During the later stages of middle ear development, prior to the onset of hearing, middle ear cavitation occurs, involving clearance of mesenchyme from the middle ear cavity while the immature cartilaginous ossicles attain appropriate size and ossify. Using in situ hybridization, we detected expression of Thra and Thrb genes encoding thyroid hormone receptors α1 and β (TRα1 and TRβ, respectively) in the immature ossicles, surrounding mesenchyme and tympanic membrane in the mouse. Thra(+/PV) mice that express a dominant-negative TRα1 protein exhibited deafness with elevated auditory thresholds and a range of middle ear abnormalities including chronic persistence of mesenchyme in the middle ear into adulthood, markedly enlarged ossicles, and delayed ossification of the ossicles. Congenitally hypothyroid Tshr(-/-) mice and TR-deficient Thra1(-/-);Thrb(-/-) mice displayed similar abnormalities. These findings demonstrate that middle ear maturation is TR dependent and suggest that the middle ear is a sensitive target for thyroid hormone in development.
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Affiliation(s)
- Emily A Cordas
- Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, 10 Center Drive, Bethesda, Maryland 20892-1772, USA
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Su PH, Liu YF, Yu JS, Chen JY, Chen SJ, Lai YJ. Facial asymmetry and clinical manifestations in patients with novel insertion of the TCOF1 gene. Clin Genet 2011; 82:460-5. [PMID: 21848650 DOI: 10.1111/j.1399-0004.2011.01765.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This study explored the role of TCOF1 insertion mutations in Taiwanese patients with craniofacial anomalies. Twelve patients with single or multiple, asymmetrical congenital craniofacial anomalies were enrolled. Genomic DNA was prepared from leukocytes; the coding regions of TCOF1 were analyzed by polymerase chain reaction and direct sequencing. Clinical manifestations were correlated to the TCOF1 mutation. Six of 12 patients diagnosed with hemifacial microsomia exhibited a novel insertion mutation 4127 ins G (frameshift) in exon 24 in the TCOF1 gene. All six patients were diagnosed with anomalies on the left side. In addition, four of these six patients had hearing impairment; three had other major anomalies; and two had developmental delay. The insertion caused a frameshift, an early truncation, the loss of two putative nuclear localization signals (residues 1404-1420 and 1424-1440), and the loss of coiled coil domain (1406-1426) in treacle protein. These findings support the existence of two regulators of growth of the mandibular condyles.
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Affiliation(s)
- P-H Su
- Division of Genetics, Department of Pediatrics School of Medicine Department of Biomedical Sciences, Chung Shan Medical University, Taichung City, Taiwan
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