1
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Żak M, Støle TP, Plagnol V, Daudet N. Regulation of otic neurosensory specification by Notch and Wnt signalling: insights from RNA-seq screenings in the embryonic chicken inner ear. Front Cell Dev Biol 2023; 11:1245330. [PMID: 37900277 PMCID: PMC10600479 DOI: 10.3389/fcell.2023.1245330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
The Notch and Wnt signalling pathways play key roles in the formation of inner ear sensory organs, but little is known about their transcriptional effectors and targets in this context. Here, we perturbed Notch and Wnt activities in the embryonic chicken otic vesicle using pharmacological treatment or in ovo electroporation of plasmid DNA, and used RNA-Seq to analyse the resulting changes in gene expression. Compared to pharmacological treatments, in ovo electroporation changed the expression of fewer genes, a likely consequence of the variability and mosaicism of transfection. The pharmacological inhibition of Notch activity induced a rapid change in the expression of known effectors of this pathway and genes associated with neurogenesis, consistent with a switch towards an otic neurosensory fate. The Wnt datasets contained many genes associated with a neurosensory biological function, confirming the importance of this pathway for neurosensory specification in the otocyst. Finally, the results of a preliminary gain-of-function screening of selected transcription factors and Wnt signalling components suggest that the endogenous programs of otic neurosensory specification are very robust, and in general unaffected by the overexpression of a single factor. Altogether this work provides new insights into the effectors and candidate targets of the Notch and Wnt pathways in the early developing inner ear and could serve as a useful reference for future functional genomics experiments in the embryonic avian inner ear.
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Affiliation(s)
- Magdalena Żak
- UCL Ear Institute, University College London, London, United Kingdom
| | - Thea P. Støle
- UCL Ear Institute, University College London, London, United Kingdom
| | - Vincent Plagnol
- Genetics Institute, University College London, London, United Kingdom
| | - Nicolas Daudet
- UCL Ear Institute, University College London, London, United Kingdom
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2
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Chen Y, Lee JH, Li J, Park S, Flores MCP, Peguero B, Kersigo J, Kang M, Choi J, Levine L, Gratton MA, Fritzsch B, Yamoah EN. Genetic and pharmacologic alterations of claudin9 levels suffice to induce functional and mature inner hair cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.08.561387. [PMID: 37873357 PMCID: PMC10592694 DOI: 10.1101/2023.10.08.561387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Hearing loss is the most common form of sensory deficit. It occurs predominantly due to hair cell (HC) loss. Mammalian HCs are terminally differentiated by birth, making HC loss incurable. Here, we show the pharmacogenetic downregulation of Cldn9, a tight junction protein, generates robust supernumerary inner HCs (IHCs) in mice. The putative ectopic IHCs have functional and synaptic features akin to typical IHCs and were surprisingly and remarkably preserved for at least fifteen months >50% of the mouse's life cycle. In vivo, Cldn9 knockdown using shRNA on postnatal days (P) P1-7 yielded analogous functional putative ectopic IHCs that were equally durably conserved. The findings suggest that Cldn9 levels coordinate embryonic and postnatal HC differentiation, making it a viable target for altering IHC development pre- and post-terminal differentiation.
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Affiliation(s)
- Yingying Chen
- University of Nevada, Reno, School of Medicine, Department of Physiology and Cell Biology, Reno NV 89557
- Indiana University School of Medicine, Department of Pharmacology and Toxicology, Indianapolis, IN, 46202, USA
| | - Jeong Han Lee
- University of Nevada, Reno, School of Medicine, Department of Physiology and Cell Biology, Reno NV 89557
| | - Jin Li
- Department of Otolaryngology, University of Washington Seattle, WA, USA
| | - Seojin Park
- University of Nevada, Reno, School of Medicine, Department of Physiology and Cell Biology, Reno NV 89557
- Prestige Biopharma, 11-12F, 44, Myongjigukje7-ro, Gangseo-gu, Busan, South Korea 67264
| | - Maria C. Perez Flores
- University of Nevada, Reno, School of Medicine, Department of Physiology and Cell Biology, Reno NV 89557
| | - Braulio Peguero
- Otolaryngology-Head, Neck Surgery, St. Louis University, St. Louis, Missouri 63108
| | | | - Mincheol Kang
- University of Nevada, Reno, School of Medicine, Department of Physiology and Cell Biology, Reno NV 89557
- Prestige Biopharma, 11-12F, 44, Myongjigukje7-ro, Gangseo-gu, Busan, South Korea 67264
| | - Jinsil Choi
- University of Nevada, Reno, School of Medicine, Department of Physiology and Cell Biology, Reno NV 89557
| | | | | | | | - Ebenezer N. Yamoah
- University of Nevada, Reno, School of Medicine, Department of Physiology and Cell Biology, Reno NV 89557
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3
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Oguma T, Takigawa-Imamura H, Shinoda T, Ogura S, Uemura A, Miyata T, Maini PK, Miura T. Analyzing the effect of cell rearrangement on Delta-Notch pattern formation. Phys Rev E 2023; 107:064404. [PMID: 37464594 DOI: 10.1103/physreve.107.064404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 04/24/2023] [Indexed: 07/20/2023]
Abstract
The Delta-Notch system plays a vital role in many areas of biology and typically forms a salt and pepper pattern in which cells strongly expressing Delta and cells strongly expressing Notch are alternately aligned via lateral inhibition. In this study, we consider cell rearrangement events, such as cell mixing and proliferation, that alter the spatial structure itself and affect the pattern dynamics. We model cell rearrangement events by a Poisson process and analyze the model while preserving the discrete properties of the spatial structure. We investigate the effects of the intermittent perturbations arising from these cell rearrangement events on the discrete spatial structure itself in the context of pattern formation and by using an analytical approach, coupled with numerical simulation. We find that the homogeneous expression pattern is stabilized if the frequency of cell rearrangement events is sufficiently large. We analytically obtain the balanced frequencies of the cell rearrangement events where the decrease of the pattern amplitude, as a result of cell rearrangement, is balanced by the increase in amplitude due to the Delta-Notch interaction dynamics. Our framework, while applied here to the specific case of the Delta-Notch system, is applicable more widely to other pattern formation mechanisms.
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Affiliation(s)
- Toshiki Oguma
- Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | | | - Tomoyasu Shinoda
- Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Shuntaro Ogura
- Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
| | - Akiyoshi Uemura
- Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
| | - Takaki Miyata
- Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Philip K Maini
- Wolfson Centre for Mathematical Biology, Mathematical Institute, Oxford OX2 6GG, United Kingdom
| | - Takashi Miura
- Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
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4
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Vázquez-Ulloa E, Lin KL, Lizano M, Sahlgren C. Reversible and bidirectional signaling of notch ligands. Crit Rev Biochem Mol Biol 2022; 57:377-398. [PMID: 36048510 DOI: 10.1080/10409238.2022.2113029] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Notch signaling pathway is a direct cell-cell communication system involved in a wide variety of biological processes, and its disruption is observed in several pathologies. The pathway is comprised of a ligand-expressing (sender) cell and a receptor-expressing (receiver) cell. The canonical ligands are members of the Delta/Serrate/Lag-1 (DSL) family of proteins. Their binding to a Notch receptor in a neighboring cell induces a conformational change in the receptor, which will undergo regulated intramembrane proteolysis (RIP), liberating the Notch intracellular domain (NICD). The NICD is translocated to the nucleus and promotes gene transcription. It has been demonstrated that the ligands can also undergo RIP and nuclear translocation, suggesting a function for the ligands in the sender cell and possible bidirectionality of the Notch pathway. Although the complete mechanism of ligand processing is not entirely understood, and its dependence on Notch receptors has not been ruled out. Also, ligands have autonomous functions beyond Notch activation. Here we review the concepts of reverse and bidirectional signalization of DSL proteins and discuss the characteristics that make them more than just ligands of the Notch pathway.
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Affiliation(s)
- Elenaé Vázquez-Ulloa
- Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Kai-Lan Lin
- Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Marcela Lizano
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Departamento de Medicina Genomica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Cecilia Sahlgren
- Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland.,Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
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5
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Li S, Fan T, Li C, Wang Y, Li J, Liu Z. Fate-mapping analysis of cochlear cells expressing Atoh1 mRNA via a new Atoh1 3*HA-P2A-Cre knockin mouse strain. Dev Dyn 2022; 251:1156-1174. [PMID: 35038200 DOI: 10.1002/dvdy.453] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Atoh1 is recognized to be essential for cochlear hair cell (HC) development. However, Atoh1 temporal and spatial expression patterns remain widely debated. Here, we aimed to obtain evidence to resolve the controversies regarding Atoh1 expression by generating a new knockin mouse strain: Atoh13*HA-P2A-Cre . RESULTS Fate-mapping analysis of Atoh13*HA-P2A-Cre/+ ; Rosa26-CAG-LSL-tdTomato (Ai9)/+ mice enabled us to concurrently characterize the temporal expression of Atoh1 protein (through HA-tag immunostaining) and visualize the cells expressing Atoh1 mRNA (as tdTomato+ cells). Our findings show that whereas Atoh1 mRNA expression is rapidly turned on in early cochlear progenitors, Atoh1 protein is only detected in differentiating HCs or progenitors just committed to the HC fate. Cre activity is also stronger in Atoh13*HA-P2A-Cre/+ than in previous mouse models, because almost all cochlear HCs and nearby supporting cells here are tdTomato+. Furthermore, tdTomato, but not HA, is expressed in middle and apical spiral ganglion neurons. CONCLUSION Collectively, our findings indicate that Atoh13*HA-P2A-Cre can serve as a powerful genetic model in the developmental biology field. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Shuting Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Ting Fan
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine, National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Chao Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yunfeng Wang
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine, National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Jian Li
- Clinical Laboratory Center, Children's Hospital of Fudan University, Shanghai, China
| | - Zhiyong Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
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6
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Rai V, Tu S, Frank JR, Zuo J. Molecular Pathways Modulating Sensory Hair Cell Regeneration in Adult Mammalian Cochleae: Progress and Perspectives. Int J Mol Sci 2021; 23:ijms23010066. [PMID: 35008497 PMCID: PMC8745006 DOI: 10.3390/ijms23010066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 12/30/2022] Open
Abstract
Noise-induced, drug-related, and age-related disabling hearing loss is a major public health problem and affect approximately 466 million people worldwide. In non-mammalian vertebrates, the death of sensory hair cells (HCs) induces the proliferation and transdifferentiation of adjacent supporting cells into new HCs; however, this capacity is lost in juvenile and adult mammalian cochleae leading to permanent hearing loss. At present, cochlear implants and hearing devices are the only available treatments and can help patients to a certain extent; however, no biological approach or FDA-approved drug is effective to treat disabling hearing loss and restore hearing. Recently, regeneration of mammalian cochlear HCs by modulating molecular pathways or transcription factors has offered some promising results, although the immaturity of the regenerated HCs remains the biggest concern. Furthermore, most of the research done is in neonates and not in adults. This review focuses on critically summarizing the studies done in adult mammalian cochleae and discusses various strategies to elucidate novel transcription factors for better therapeutics.
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Affiliation(s)
| | | | | | - Jian Zuo
- Correspondence: ; Tel.: +1-(402)-280-2916
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7
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Żak M, Daudet N. A gradient of Wnt activity positions the neurosensory domains of the inner ear. eLife 2021; 10:59540. [PMID: 33704062 PMCID: PMC7993990 DOI: 10.7554/elife.59540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 03/09/2021] [Indexed: 12/25/2022] Open
Abstract
The auditory and vestibular organs of the inner ear and the neurons that innervate them originate from Sox2-positive and Notch-active neurosensory domains specified at early stages of otic development. Sox2 is initially present throughout the otic placode and otocyst, and then it becomes progressively restricted to a ventro-medial domain. Using gain- and loss-of-function approaches in the chicken otocyst, we show that these early changes in Sox2 expression are regulated in a dose-dependent manner by Wnt/beta-catenin signalling. Both high and very low levels of Wnt activity repress Sox2 and neurosensory competence. However, intermediate levels allow the maintenance of Sox2 expression and sensory organ formation. We propose that a dorso-ventral (high-to-low) gradient and wave of Wnt activity initiated at the dorsal rim of the otic placode progressively restricts Sox2 and Notch activity to the ventral half of the otocyst, thereby positioning the neurosensory competent domains in the inner ear.
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Affiliation(s)
- Magdalena Żak
- UCL Ear Institute, University College London, London, United Kingdom
| | - Nicolas Daudet
- UCL Ear Institute, University College London, London, United Kingdom
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8
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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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9
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Chen Y, Lu X, Guo L, Ni W, Zhang Y, Zhao L, Wu L, Sun S, Zhang S, Tang M, Li W, Chai R, Li H. Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea. Front Mol Neurosci 2017; 10:426. [PMID: 29311816 PMCID: PMC5742997 DOI: 10.3389/fnmol.2017.00426] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/06/2017] [Indexed: 12/11/2022] Open
Abstract
Hair cell (HC) loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh) protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway.
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Affiliation(s)
- Yan Chen
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Wenli Ni
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Yanping Zhang
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Liping Zhao
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Lingjie Wu
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.,Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.,Shanghai Engineering Research Centre of Cochlear Implant, Shanghai, China
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10
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Mann ZF, Gálvez H, Pedreno D, Chen Z, Chrysostomou E, Żak M, Kang M, Canden E, Daudet N. Shaping of inner ear sensory organs through antagonistic interactions between Notch signalling and Lmx1a. eLife 2017; 6:e33323. [PMID: 29199954 PMCID: PMC5724992 DOI: 10.7554/elife.33323] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/02/2017] [Indexed: 12/19/2022] Open
Abstract
The mechanisms of formation of the distinct sensory organs of the inner ear and the non-sensory domains that separate them are still unclear. Here, we show that several sensory patches arise by progressive segregation from a common prosensory domain in the embryonic chicken and mouse otocyst. This process is regulated by mutually antagonistic signals: Notch signalling and Lmx1a. Notch-mediated lateral induction promotes prosensory fate. Some of the early Notch-active cells, however, are normally diverted from this fate and increasing lateral induction produces misshapen or fused sensory organs in the chick. Conversely Lmx1a (or cLmx1b in the chick) allows sensory organ segregation by antagonizing lateral induction and promoting commitment to the non-sensory fate. Our findings highlight the dynamic nature of sensory patch formation and the labile character of the sensory-competent progenitors, which could have facilitated the emergence of new inner ear organs and their functional diversification in the course of evolution.
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Affiliation(s)
- Zoe F Mann
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - Héctor Gálvez
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - David Pedreno
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - Ziqi Chen
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | | | - Magdalena Żak
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | - Miso Kang
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
| | | | - Nicolas Daudet
- The Ear InstituteUniversity College LondonLondonUnited Kingdom
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11
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Siebel C, Lendahl U. Notch Signaling in Development, Tissue Homeostasis, and Disease. Physiol Rev 2017; 97:1235-1294. [PMID: 28794168 DOI: 10.1152/physrev.00005.2017] [Citation(s) in RCA: 590] [Impact Index Per Article: 84.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/19/2017] [Accepted: 05/26/2017] [Indexed: 02/07/2023] Open
Abstract
Notch signaling is an evolutionarily highly conserved signaling mechanism, but in contrast to signaling pathways such as Wnt, Sonic Hedgehog, and BMP/TGF-β, Notch signaling occurs via cell-cell communication, where transmembrane ligands on one cell activate transmembrane receptors on a juxtaposed cell. Originally discovered through mutations in Drosophila more than 100 yr ago, and with the first Notch gene cloned more than 30 yr ago, we are still gaining new insights into the broad effects of Notch signaling in organisms across the metazoan spectrum and its requirement for normal development of most organs in the body. In this review, we provide an overview of the Notch signaling mechanism at the molecular level and discuss how the pathway, which is architecturally quite simple, is able to engage in the control of cell fates in a broad variety of cell types. We discuss the current understanding of how Notch signaling can become derailed, either by direct mutations or by aberrant regulation, and the expanding spectrum of diseases and cancers that is a consequence of Notch dysregulation. Finally, we explore the emerging field of Notch in the control of tissue homeostasis, with examples from skin, liver, lung, intestine, and the vasculature.
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Affiliation(s)
- Chris Siebel
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Urban Lendahl
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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12
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Cheng C, Guo L, Lu L, Xu X, Zhang S, Gao J, Waqas M, Zhu C, Chen Y, Zhang X, Xuan C, Gao X, Tang M, Chen F, Shi H, Li H, Chai R. Characterization of the Transcriptomes of Lgr5+ Hair Cell Progenitors and Lgr5- Supporting Cells in the Mouse Cochlea. Front Mol Neurosci 2017; 10:122. [PMID: 28491023 PMCID: PMC5405134 DOI: 10.3389/fnmol.2017.00122] [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] [Received: 02/25/2017] [Accepted: 04/11/2017] [Indexed: 12/27/2022] Open
Abstract
Cochlear supporting cells (SCs) have been shown to be a promising resource for hair cell (HC) regeneration in the neonatal mouse cochlea. Previous studies have reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo and thus are considered to be inner ear progenitor cells. Lgr5+ progenitors are able to regenerate more HCs than Lgr5- SCs, and it is important to understand the mechanism behind the proliferation and HC regeneration of these progenitors. Here, we isolated Lgr5+ progenitors and Lgr5- SCs from Lgr5-EGFP-CreERT2/Sox2-CreERT2/Rosa26-tdTomato mice via flow cytometry. As expected, we found that Lgr5+ progenitors had significantly higher proliferation and HC regeneration ability than Lgr5- SCs. Next, we performed RNA-Seq to determine the gene expression profiles of Lgr5+ progenitors and Lgr5- SCs. We analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors and Lgr5- SCs, and we found 8 cell cycle genes, 9 transcription factors, and 24 cell signaling pathway genes that were uniquely expressed in one population but not the other. Last, we made a protein–protein interaction network to further analyze the role of these differentially expressed genes. In conclusion, we present a set of genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these might serve as potential new therapeutic targets for HC regeneration.
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Affiliation(s)
- Cheng Cheng
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China.,Research Institute of OtolaryngologyNanjing, China.,Co-innovation Center of Neuroregeneration, Nantong UniversityNantong, China
| | - Luo Guo
- Department of Otorhinolaryngology, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning CommissionShanghai, China
| | - Ling Lu
- Department of Otolaryngology-Head and Neck Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical SchoolNanjing, China.,Department of Otolaryngology-Head and Neck Surgery, Drum Tower Clinical Medical College of Nanjing Medical UniversityNanjing, China
| | - Xiaochen Xu
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - ShaSha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Junyan Gao
- Health Management and Policy, College of Public Health, Saint Louis University, St. LouisMO, USA
| | - Muhammad Waqas
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China.,Department of Biotechnology, Federal Urdu University of Arts, Science and TechnologyGulshan-e-Iqbal, Pakistan
| | - Chengwen Zhu
- Department of Otolaryngology-Head and Neck Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical SchoolNanjing, China
| | - Yan Chen
- Department of Otorhinolaryngology, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning CommissionShanghai, China
| | - Xiaoli Zhang
- Department of Otolaryngology-Head and Neck Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical SchoolNanjing, China
| | - Chuanying Xuan
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Xia Gao
- Department of Otolaryngology-Head and Neck Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical SchoolNanjing, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Fangyi Chen
- Department of Biomedical Engineering, Southern University of Science and TechnologyShenzhen, China
| | - Haibo Shi
- Department of Otorhinolaryngology Head and Neck Surgery, The Sixth People's Hospital, Shanghai Jiao Tong UniversityShanghai, China
| | - Huawei Li
- Department of Otorhinolaryngology, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning CommissionShanghai, China.,Institutes of Biomedical Sciences, Fudan UniversityShanghai, China.,Shanghai Engineering Research Centre of Cochlear ImplantShanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China.,Research Institute of OtolaryngologyNanjing, China.,Co-innovation Center of Neuroregeneration, Nantong UniversityNantong, China
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13
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Inomata H. Scaling of pattern formations and morphogen gradients. Dev Growth Differ 2017; 59:41-51. [PMID: 28097650 DOI: 10.1111/dgd.12337] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/08/2016] [Accepted: 12/08/2016] [Indexed: 12/31/2022]
Abstract
The concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. Morphogen-dependent pattern formations show robustness despite various perturbations. Although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. Furthermore, even when the blastula embryo of Xenopus laevis is bisected into dorsal and ventral halves, the dorsal half of the embryo leads to proportionally patterned half-sized embryos. This robustness of pattern formation despite size variations is termed as scaling. In this review, I focused on the morphogen-dependent dorsal-ventral axis formation in Xenopus and described how morphogens form a proper gradient shape according to the embryo size.
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Affiliation(s)
- Hidehiko Inomata
- Axial Pattern Dynamics Team, Center for Developmental Biology, RIKEN, Kobe, Japan
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14
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Żak M, Klis SFL, Grolman W. The Wnt and Notch signalling pathways in the developing cochlea: Formation of hair cells and induction of regenerative potential. Int J Dev Neurosci 2015; 47:247-58. [PMID: 26471908 DOI: 10.1016/j.ijdevneu.2015.09.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 09/25/2015] [Accepted: 09/26/2015] [Indexed: 12/21/2022] Open
Abstract
The Wnt and Notch signalling pathways control proliferation, specification, and cell fate choices during embryonic development and in adult life. Hence, there is much interest in both signalling pathways in the context of stem cell biology and tissue regeneration. In the developing ear, the Wnt and Notch signalling pathways specify otic cells and refine the ventral boundary of the otic placode. Since both signalling pathways control events essential for the formation of sensory cells, such as proliferation and hair cell differentiation, these pathways could hold promise for the regeneration of hair cells in adult mammalian cochlea. Indeed, modulating either the Wnt or Notch pathways can trigger the regenerative potential of supporting cells. In the neonatal mouse cochlea, Notch-mediated regeneration of hair cells partially depends on Wnt signalling, which implies an interaction between the pathways. This review presents how the Wnt and Notch signalling pathways regulate the formation of sensory hair cells and how modulating their activity induces regenerative potential in the mammalian cochlea.
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Affiliation(s)
- Magdalena Żak
- Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Room G.02.531, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
| | - Sjaak F L Klis
- Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Room G.02.531, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Wilko Grolman
- Department of Otorhinolaryngology and Head & Neck Surgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Room G.02.531, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
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15
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Expression and Misexpression of the miR-183 Family in the Developing Hearing Organ of the Chicken. PLoS One 2015; 10:e0132796. [PMID: 26176784 PMCID: PMC4503353 DOI: 10.1371/journal.pone.0132796] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/19/2015] [Indexed: 12/31/2022] Open
Abstract
The miR-183 family consists of 3 related microRNAs (miR-183, miR-96, miR-182) that are required to complete maturation of primary sensory cells in the mammalian inner ear. Because the level of these microRNAs is not uniform across hair cell subtypes in the murine cochlea, the question arises as to whether hair cell phenotypes are influenced by microRNA expression levels. To address this, we used the chicken embryo to study expression and misexpression of this gene family. By in situ hybridization, expression of all 3 microRNAs is robust in immature hair cells of both auditory and vestibular organs and is present in the statoacoustic ganglion. The auditory organ, called the basilar papilla, shows a weak radial gradient (highest on the neural side) in prosensory cells near the base on embryonic day 7. About nine days later, the basilar papilla also displays a longitudinal gradient (highest in apical hair cells) for the 3 microRNAs. Tol2-mediated gene delivery was used to ask whether cell phenotypes are malleable when the prosensory epithelium was forced to overexpress the miR-183 family. The expression plasmid included EGFP as a reporter located upstream of an intron carrying the microRNA genes. The vectors were electroporated into the otic cup/vesicle, resulting in strong co-expression of EGFP and the miR-183 family that persisted for at least 2 weeks. This manipulation did not generate ectopic hair cells in non-sensory territories of the cochlear duct, although within the basilar papilla, hair cells were over-represented relative to supporting cells. There was no evidence for a change in hair cell phenotypes, such as short-to-tall, or basal-to-apical hair cell features. Therefore, while increasing expression of the miR-183 family was sufficient to influence cell lineage decisions, it did not redirect the differentiation of hair cells towards alternative radial or longitudinal phenotypes.
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16
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Eddison M, Weber SJ, Ariza-McNaughton L, Lewis J, Daudet N. Numb is not a critical regulator of Notch-mediated cell fate decisions in the developing chick inner ear. Front Cell Neurosci 2015; 9:74. [PMID: 25814931 PMCID: PMC4357303 DOI: 10.3389/fncel.2015.00074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 02/19/2015] [Indexed: 11/27/2022] Open
Abstract
The Notch signaling pathway controls differentiation of hair cells and supporting cells in the vertebrate inner ear. Here, we have investigated whether Numb, a known regulator of Notch activity in Drosophila, is involved in this process in the embryonic chick. The chicken homolog of Numb is expressed throughout the otocyst at early stages of development and is concentrated at the basal pole of the cells. It is asymmetrically allocated at some cell divisions, as in Drosophila, suggesting that it could act as a determinant inherited by one of the two daughter cells and favoring adoption of a hair-cell fate. To test the implication of Numb in hair cell fate decisions and the regulation of Notch signaling, we used different methods to overexpress Numb at different stages of inner ear development. We found that sustained or late Numb overexpression does not promote hair cell differentiation, and Numb does not prevent the reception of Notch signaling. Surprisingly, none of the Numb-overexpressing cells differentiated into hair cells, suggesting that high levels of Numb protein could interfere with intracellular processes essential for hair cell survival. However, when Numb was overexpressed early and more transiently during ear development, no effect on hair cell formation was seen. These results suggest that in the inner ear at least, Numb does not significantly repress Notch activity and that its asymmetric distribution in dividing precursor cells does not govern the choice between hair cell and supporting cell fates.
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Affiliation(s)
- Mark Eddison
- Howard Hughes Medical Institute, Janelia Research Campus Ashburn, VA, USA
| | - Sara J Weber
- Ear Institute, University College London London, UK
| | - Linda Ariza-McNaughton
- Haematopoietic Stem cell Laboratory, Cancer Research UK, London Research Institute London, UK
| | - Julian Lewis
- Formerly of Vertebrate Development Laboratory, Cancer Research UK London, UK
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17
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Matsuda M, Koga M, Woltjen K, Nishida E, Ebisuya M. Synthetic lateral inhibition governs cell-type bifurcation with robust ratios. Nat Commun 2015; 6:6195. [PMID: 25652697 DOI: 10.1038/ncomms7195] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/05/2015] [Indexed: 01/20/2023] Open
Abstract
Cell-type diversity in multicellular organisms is created through a series of binary cell fate decisions. Lateral inhibition controlled by Delta-Notch signalling is the core mechanism for the choice of alternative cell types by homogeneous neighbouring cells. Here, we show that cells engineered with a Delta-Notch-dependent lateral inhibition circuit spontaneously bifurcate into Delta-positive and Notch-active cell populations. The synthetic lateral inhibition circuit comprises transcriptional repression of Delta and intracellular feedback of Lunatic fringe (Lfng). The Lfng-feedback subcircuit, even alone, causes the autonomous cell-type bifurcation. Furthermore, the ratio of two cell populations bifurcated by lateral inhibition is reproducible and robust against perturbation. The cell-type ratio is adjustable by the architecture of the lateral inhibition circuit as well as the degree of cell-cell attachment. Thus, the minimum lateral inhibition mechanism between adjacent cells not only serves as a binary cell-type switch of individual cells but also governs the cell-type ratio at the cell-population level.
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Affiliation(s)
- Mitsuhiro Matsuda
- 1] RIKEN Center for Developmental Biology, Kobe 650-0047, Japan [2] Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Kyoto 606-8501, Japan [3] Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Makito Koga
- 1] RIKEN Center for Developmental Biology, Kobe 650-0047, Japan [2] Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Kyoto 606-8501, Japan [3] Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Knut Woltjen
- 1] Center for iPS Cell Research and Application, Kyoto University, Kyoto 606-8507, Japan [2] Hakubi Center for Advanced Research, Kyoto University, Kyoto 606-8501, Japan
| | - Eisuke Nishida
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Miki Ebisuya
- 1] RIKEN Center for Developmental Biology, Kobe 650-0047, Japan [2] Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Kyoto 606-8501, Japan [3] Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
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18
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Nakajima Y. Signaling regulating inner ear development: cell fate determination, patterning, morphogenesis, and defects. Congenit Anom (Kyoto) 2015; 55:17-25. [PMID: 25040109 DOI: 10.1111/cga.12072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 06/07/2014] [Indexed: 12/28/2022]
Abstract
The membranous labyrinth of the inner ear is a highly complex organ that detects sound and balance. Developmental defects in the inner ear cause congenital hearing loss and balance disorders. The membranous labyrinth consists of three semicircular ducts, the utricle, saccule, and endolymphatic ducts, and the cochlear duct. These complex structures develop from the simple otic placode, which is established in the cranial ectoderm adjacent to the neural crest at the level of the hindbrain at the early neurula stage. During development, the otic placode invaginates to form the otic vesicle, which subsequently gives rise to neurons for the vestibulocochlear ganglion, the non-sensory and sensory epithelia of the membranous labyrinth that includes three ampullary crests, two maculae, and the organ of Corti. Combined paracrine and autocrine signals including fibroblast growth factor, Wnt, retinoic acid, hedgehog, and bone morphogenetic protein regulate fate determination, axis formation, and morphogenesis in the developing inner ear. Juxtacrine signals mediated by Notch pathways play a role in establishing the sensory epithelium, which consists of mechanosensory hair cells and supporting cells. The highly differentiated organ of Corti, which consists of uniformly oriented inner/outer hair cells and specific supporting cells, develops during fetal development. Developmental alterations/arrest causes congenital malformations in the inner ear in a spatiotemporal-restricted manner. A clearer understanding of the mechanisms underlying inner ear development is important not only for the management of patients with congenital inner ear malformations, but also for the development of regenerative therapy for impaired function.
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Affiliation(s)
- Yuji Nakajima
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Osaka City University, Osaka, Japan
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19
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Petrovic J, Gálvez H, Neves J, Abelló G, Giraldez F. Differential regulation of Hes/Hey genes during inner ear development. Dev Neurobiol 2014; 75:703-20. [PMID: 25363712 DOI: 10.1002/dneu.22243] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/28/2014] [Indexed: 11/09/2022]
Abstract
Notch signaling plays a crucial role during inner ear development and regeneration. Hes/Hey genes encode for bHLH transcription factors identified as Notch targets. We have studied the expression and regulation of Hes/Hey genes during inner ear development in the chicken embryo. Among several Hes/Hey genes examined, only Hey1 and Hes5 map to the sensory regions, although with salient differences. Hey1 expression follows Jag1 expression except at early prosensory stages while Hes5 expression corresponds well to Dl1 expression throughout otic development. Although Hey1 and Hes5 are direct Notch downstream targets, they differ in the level of Notch required for activation. Moreover, they also differ in mRNA stability, showing different temporal decays after Notch blockade. In addition, Bmp, Wnt and Fgf pathways also modify Hey1 and Hes5 expression in the inner ear. Particularly, the Wnt pathway modulates Hey1 and Jag1 expression. Finally, gain of function experiments show that Hey1 and Hes5 cross-regulate each other in a complex manner. Both Hey1 and Hes5 repress Dl1 and Hes5 expression, suggesting that they prevent the transition to differentiation stages, probably by preventing Atoh1 expression. In spite of its association with Jag1, Hey1 does not seem to be instrumental for lateral induction as it does not promote Jag1 expression. We suggest that, besides being both targets of Notch, Hey1 and Hes5 are subject to a rather complex regulation that includes the stability of their transcripts, cross regulation and other signaling pathways.
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Affiliation(s)
- Jelena Petrovic
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
| | - Hector Gálvez
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
| | - Joana Neves
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
| | - Gina Abelló
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
| | - Fernando Giraldez
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
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20
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Radosevic M, Fargas L, Alsina B. The role of her4 in inner ear development and its relationship with proneural genes and Notch signalling. PLoS One 2014; 9:e109860. [PMID: 25299450 PMCID: PMC4192589 DOI: 10.1371/journal.pone.0109860] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/08/2014] [Indexed: 01/13/2023] Open
Abstract
The generation of sensory neurons and hair cells of the inner ear is under tight control. Different members of the Hairy and Enhancer of Split genes (HES) are expressed in the inner ear, their full array of functions still not being disclosed. We have previously shown that zebrafish her9 acts as a patterning gene to restrict otic neurogenesis to an anterior domain. Here, we disclose the role of another her gene, her4, a zebrafish ortholog of Hes5 that is expressed in the neurogenic and sensory domains of the inner ear. The expression of her4 is highly dynamic and spatiotemporally regulated. We demonstrate by loss of function experiments that in the neurogenic domain her4 expression is under the regulation of neurogenin1 (neurog1) and the Notch pathway. Moreover, her4 participates in lateral inhibition during otic neurogenesis since her4 knockdown results in overproduction of the number of neurog1 and deltaB-positive otic neurons. In contrast, during sensorigenesis her4 is initially Notch-independent and induced by atoh1b in a broad prosensory domain. At later stages her4 expression becomes Notch-dependent in the future sensory domains but loss of her4 does not result in hair cell overproduction, suggesting that there other her genes can compensate its function.
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Affiliation(s)
- Marija Radosevic
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
| | - Laura Fargas
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
| | - Berta Alsina
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
- * E-mail:
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21
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A gradient of Bmp7 specifies the tonotopic axis in the developing inner ear. Nat Commun 2014; 5:3839. [PMID: 24845721 PMCID: PMC4264580 DOI: 10.1038/ncomms4839] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 04/08/2014] [Indexed: 11/09/2022] Open
Abstract
The auditory systems of animals that perceive sounds in air are organized to separate sound stimuli into their component frequencies. Individual tones then stimulate mechanosensory hair cells located at different positions on an elongated frequency (tonotopic) axis. During development, immature hair cells located along the axis must determine their tonotopic position in order to generate frequency-specific characteristics. Expression profiling along the developing tonotopic axis of the chick basilar papilla (BP) identified a gradient of Bmp7. Disruption of that gradient in vitro or in ovo induces changes in hair cell morphologies consistent with a loss of tonotopic organization and the formation of an organ with uniform frequency characteristics. Further, the effects of Bmp7 in determination of positional identity are shown to be mediated through activation of the Mapk, Tak1. These results indicate that graded, Bmp7-dependent, activation of Tak1 signalling controls the determination of frequency-specific hair cell characteristics along the tonotopic axis.
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22
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Petrovic J, Formosa-Jordan P, Luna-Escalante JC, Abelló G, Ibañes M, Neves J, Giraldez F. Ligand-dependent Notch signaling strength orchestrates lateral induction and lateral inhibition in the developing inner ear. Development 2014; 141:2313-24. [PMID: 24821984 DOI: 10.1242/dev.108100] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
During inner ear development, Notch exhibits two modes of operation: lateral induction, which is associated with prosensory specification, and lateral inhibition, which is involved in hair cell determination. These mechanisms depend respectively on two different ligands, jagged 1 (Jag1) and delta 1 (Dl1), that rely on a common signaling cascade initiated after Notch activation. In the chicken otocyst, expression of Jag1 and the Notch target Hey1 correlates well with lateral induction, whereas both Jag1 and Dl1 are expressed during lateral inhibition, as are Notch targets Hey1 and Hes5. Here, we show that Jag1 drives lower levels of Notch activity than Dl1, which results in the differential expression of Hey1 and Hes5. In addition, Jag1 interferes with the ability of Dl1 to elicit high levels of Notch activity. Modeling the sensory epithelium when the two ligands are expressed together shows that ligand regulation, differential signaling strength and ligand competition are crucial to allow the two modes of operation and for establishing the alternate pattern of hair cells and supporting cells. Jag1, while driving lateral induction on its own, facilitates patterning by lateral inhibition in the presence of Dl1. This novel behavior emerges from Jag1 acting as a competitive inhibitor of Dl1 for Notch signaling. Both modeling and experiments show that hair cell patterning is very robust. The model suggests that autoactivation of proneural factor Atoh1, upstream of Dl1, is a fundamental component for robustness. The results stress the importance of the levels of Notch signaling and ligand competition for Notch function.
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Affiliation(s)
- Jelena Petrovic
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), 08003 Barcelona, Spain
| | - Pau Formosa-Jordan
- Departament d'Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Juan C Luna-Escalante
- Departament d'Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Gina Abelló
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), 08003 Barcelona, Spain
| | - Marta Ibañes
- Departament d'Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Joana Neves
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), 08003 Barcelona, Spain
| | - Fernando Giraldez
- Developmental Biology Unit, CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona (PRBB), 08003 Barcelona, Spain
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23
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Al-Awqati Q. Cell biology of the intercalated cell in the kidney. FEBS Lett 2013; 587:1911-4. [PMID: 23684635 DOI: 10.1016/j.febslet.2013.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/02/2013] [Accepted: 05/02/2013] [Indexed: 12/13/2022]
Abstract
The intercalated cell of the collecting tubule of the mammalian kidney is specialized for the transport of H(+) and HCO3. They exist in two forms; one specialized for acid secretion and the other secretes HCO3 into the urine. We discovered many years ago that feeding animals an acid diet converts the HCO3 secreting form to an acid secreting type. Here I discuss the molecular basis of this transformation. The conversion of the cell types is mediated by an extracellular matrix protein hensin (also known as DMBT1). However much remains to be identified in the differentiation of these cells.
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Affiliation(s)
- Qais Al-Awqati
- Department of Medicine, College of Physicians & Surgeons of Columbia University, 630 W 168th Str., New York, NY 10032, USA.
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24
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Kiernan AE. Notch signaling during cell fate determination in the inner ear. Semin Cell Dev Biol 2013; 24:470-9. [PMID: 23578865 DOI: 10.1016/j.semcdb.2013.04.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/27/2013] [Accepted: 04/02/2013] [Indexed: 01/05/2023]
Abstract
In the inner ear, Notch signaling has been proposed to specify the sensory regions, as well as regulate the differentiation of hair cells and supporting cell within those regions. In addition, Notch plays an important role in otic neurogenesis, by determining which cells differentiate as neurons, sensory cells and non-sensory cells. Here, I review the evidence for the complex and myriad roles Notch participates in during inner ear development. A particular challenge for those studying ear development and Notch is to decipher how activation of a single pathway can lead to different outcomes within the ear, which may include changes in the intrinsic properties of the cell, Notch modulation, and potential non-canonical pathways.
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Affiliation(s)
- Amy E Kiernan
- Department of Ophthalmology, University of Rochester, Rochester, NY 14642, United States.
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25
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Inner ear supporting cells: rethinking the silent majority. Semin Cell Dev Biol 2013; 24:448-59. [PMID: 23545368 DOI: 10.1016/j.semcdb.2013.03.009] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/21/2013] [Indexed: 11/21/2022]
Abstract
Sensory epithelia of the inner ear contain two major cell types: hair cells and supporting cells. It has been clear for a long time that hair cells play critical roles in mechanoreception and synaptic transmission. In contrast, until recently the more abundant supporting cells were viewed as serving primarily structural and homeostatic functions. In this review, we discuss the growing information about the roles that supporting cells play in the development, function and maintenance of the inner ear, their activities in pathological states, their potential for hair cell regeneration, and the mechanisms underlying these processes.
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26
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Neves J, Abelló G, Petrovic J, Giraldez F. Patterning and cell fate in the inner ear: a case for Notch in the chicken embryo. Dev Growth Differ 2012; 55:96-112. [PMID: 23252974 DOI: 10.1111/dgd.12016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/09/2012] [Accepted: 10/09/2012] [Indexed: 01/08/2023]
Abstract
The development of the inner ear provides a beautiful example of one basic problem in development, that is, to understand how different cell types are generated at specific times and domains throughout embryonic life. The functional unit of the inner ear consists of hair cells, supporting cells and neurons, all deriving from progenitor cells located in the neurosensory competent domain of the otic placode. Throughout development, the otic placode resolves into the complex inner ear labyrinth, which holds the auditory and vestibular sensory organs that are innervated in a highly specific manner. How does the early competent domain of the otic placode give rise to the diverse specialized cell types of the different sensory organs of the inner ear? We review here our current understanding on the role of Notch signaling in coupling patterning and cell fate determination during inner ear development, with a particular emphasis on contributions from the chicken embryo as a model organism. We discuss further the question of how these two processes rely on two modes of operation of the Notch signaling pathway named lateral induction and lateral inhibition.
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Affiliation(s)
- Joana Neves
- CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
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