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Teletin M, Mark M, Wendling O, Vernet N, Féret B, Klopfenstein M, Herault Y, Ghyselinck NB. Timeline of Developmental Defects Generated upon Genetic Inhibition of the Retinoic Acid Receptor Signaling Pathway. Biomedicines 2023; 11:biomedicines11010198. [PMID: 36672706 PMCID: PMC9856201 DOI: 10.3390/biomedicines11010198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/06/2023] [Indexed: 01/14/2023] Open
Abstract
It has been established for almost 30 years that the retinoic acid receptor (RAR) signalling pathway plays essential roles in the morphogenesis of a large variety of organs and systems. Here, we used a temporally controlled genetic ablation procedure to precisely determine the time windows requiring RAR functions. Our results indicate that from E8.5 to E9.5, RAR functions are critical for the axial rotation of the embryo, the appearance of the sinus venosus, the modelling of blood vessels, and the formation of forelimb buds, lung buds, dorsal pancreatic bud, lens, and otocyst. They also reveal that E9.5 to E10.5 spans a critical developmental period during which the RARs are required for trachea formation, lung branching morphogenesis, patterning of great arteries derived from aortic arches, closure of the optic fissure, and growth of inner ear structures and of facial processes. Comparing the phenotypes of mutants lacking the 3 RARs with that of mutants deprived of all-trans retinoic acid (ATRA) synthesising enzymes establishes that cardiac looping is the earliest known morphogenetic event requiring a functional ATRA-activated RAR signalling pathway.
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Affiliation(s)
- Marius Teletin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS UMR7104), Institut National de la Sante et de la Recherche Médicale (INSERM U1258), Université de Strasbourg (UNISTRA), 1 Rue Laurent Fries, BP-10142, F-67404 Illkirch Graffenstaden, France
- Service de Biologie de la Reproduction, Hôpitaux Universitaires de Strasbourg (HUS), F-67000 Strasbourg, France
| | - Manuel Mark
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS UMR7104), Institut National de la Sante et de la Recherche Médicale (INSERM U1258), Université de Strasbourg (UNISTRA), 1 Rue Laurent Fries, BP-10142, F-67404 Illkirch Graffenstaden, France
- Service de Biologie de la Reproduction, Hôpitaux Universitaires de Strasbourg (HUS), F-67000 Strasbourg, France
- Institut Clinique de la Souris (ICS), Université de Strasbourg, CNRS, INSERM, CELPHEDIA, PHENOMIN, 1 Rue Laurent Fries, 67404 Illkirch Graffenstaden, France
- Correspondence:
| | - Olivia Wendling
- Institut Clinique de la Souris (ICS), Université de Strasbourg, CNRS, INSERM, CELPHEDIA, PHENOMIN, 1 Rue Laurent Fries, 67404 Illkirch Graffenstaden, France
| | - Nadège Vernet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS UMR7104), Institut National de la Sante et de la Recherche Médicale (INSERM U1258), Université de Strasbourg (UNISTRA), 1 Rue Laurent Fries, BP-10142, F-67404 Illkirch Graffenstaden, France
| | - Betty Féret
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS UMR7104), Institut National de la Sante et de la Recherche Médicale (INSERM U1258), Université de Strasbourg (UNISTRA), 1 Rue Laurent Fries, BP-10142, F-67404 Illkirch Graffenstaden, France
| | - Muriel Klopfenstein
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS UMR7104), Institut National de la Sante et de la Recherche Médicale (INSERM U1258), Université de Strasbourg (UNISTRA), 1 Rue Laurent Fries, BP-10142, F-67404 Illkirch Graffenstaden, France
| | - Yann Herault
- Institut Clinique de la Souris (ICS), Université de Strasbourg, CNRS, INSERM, CELPHEDIA, PHENOMIN, 1 Rue Laurent Fries, 67404 Illkirch Graffenstaden, France
| | - Norbert B. Ghyselinck
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS UMR7104), Institut National de la Sante et de la Recherche Médicale (INSERM U1258), Université de Strasbourg (UNISTRA), 1 Rue Laurent Fries, BP-10142, F-67404 Illkirch Graffenstaden, France
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Cardeña-Núñez S, Callejas-Marín A, Villa-Carballar S, Rodríguez-Gallardo L, Sánchez-Guardado LÓ, Hidalgo-Sánchez M. CRABP-I Expression Patterns in the Developing Chick Inner Ear. BIOLOGY 2023; 12:biology12010104. [PMID: 36671796 PMCID: PMC9855850 DOI: 10.3390/biology12010104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/30/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
The vertebrate inner ear is a complex three-dimensional sensorial structure with auditory and vestibular functions, regarded as an excellent system for analyzing events that occur during development, such as patterning, morphogenesis, and cell specification. Retinoic acid (RA) is involved in all these development processes. Cellular retinoic acid-binding proteins (CRABPs) bind RA with high affinity, buffering cellular free RA concentrations and consequently regulating the activation of precise specification programs mediated by particular regulatory genes. In the otic vesicle, strong CRABP-I expression was detected in the otic wall's dorsomedial aspect, where the endolymphatic apparatus develops, whereas this expression was lower in the ventrolateral aspect, where part of the auditory system forms. Thus, CRABP-I proteins may play a role in the specification of the dorsal-to-ventral and lateral-to-medial axe of the otic anlagen. Regarding the developing sensory patches, a process partly involving the subdivision of a ventromedial pro-sensory domain, the CRABP-I gene displayed different levels of expression in the presumptive territory of each sensory patch, which was maintained throughout development. CRABP-I was also relevant in the acoustic-vestibular ganglion and in the periotic mesenchyme. Therefore, CRABP-I could protect RA-sensitive cells in accordance with its dissimilar concentration in specific areas of the developing chick inner ear.
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Cardeña-Núñez S, Sánchez-Guardado LÓ, Hidalgo-Sánchez M. Cyp1B1 expression patterns in the developing chick inner ear. Dev Dyn 2019; 249:410-424. [PMID: 31400045 DOI: 10.1002/dvdy.99] [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: 06/24/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Retinoic acid (RA) plays an important role in organogenesis as a paracrine signal through transcriptional regulation of an increasing number of known downstream target genes, regulating cell proliferation, and differentiation. During the development of the inner ear, RA directly governs the morphogenesis and specification processes mainly by means of RA-synthesizing retinaldehyde dehydrogenase (RALDH) enzymes. Interestingly, CYP1B1, a cytochrome P450 enzyme, is able to mediate the oxidative metabolisms also leading to RA generation, its expression patterns being associated with many known sites of RA activity. RESULTS This study describes for the first time the presence of CYP1B1 in the developing chick inner ear as a RALDH-independent RA-signaling mechanism. In our in situ hybridization analysis, Cyp1B1 expression was first observed in a domain located in the ventromedial wall of the otic anlagen, being included within the rostralmost aspect of an Fgf10-positive pan-sensory domain. As development proceeds, all identified Fgf10-positive areas were Cyp1B1 stained, with all sensory patches being Cyp1B1 positive at stage HH34, except the macula neglecta. CONCLUSIONS Cyp1B1 expression suggested a possible contribution of CYP1B1 action in the specification of the lateral-to-medial and dorsal-to-ventral axes of the developing chick inner ear.
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Affiliation(s)
- Sheila Cardeña-Núñez
- Department of Cell Biology, School of Science, University of Extremadura, Badajoz, Spain
| | - Luis Ó Sánchez-Guardado
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California
| | - Matías Hidalgo-Sánchez
- Department of Cell Biology, School of Science, University of Extremadura, Badajoz, Spain
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Retinoic Acid Signaling Mediates Hair Cell Regeneration by Repressing p27kip and sox2 in Supporting Cells. J Neurosci 2016; 35:15752-66. [PMID: 26609166 DOI: 10.1523/jneurosci.1099-15.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED During development, otic sensory progenitors give rise to hair cells and supporting cells. In mammalian adults, differentiated and quiescent sensory cells are unable to generate new hair cells when these are lost due to various insults, leading to irreversible hearing loss. Retinoic acid (RA) has strong regenerative capacity in several organs, but its role in hair cell regeneration is unknown. Here, we use genetic and pharmacological inhibition to show that the RA pathway is required for hair cell regeneration in zebrafish. When regeneration is induced by laser ablation in the inner ear or by neomycin treatment in the lateral line, we observe rapid activation of several components of the RA pathway, with dynamics that position RA signaling upstream of other signaling pathways. We demonstrate that blockade of the RA pathway impairs cell proliferation of supporting cells in the inner ear and lateral line. Moreover, in neuromast, RA pathway regulates the transcription of p27(kip) and sox2 in supporting cells but not fgf3. Finally, genetic cell-lineage tracing using Kaede photoconversion demonstrates that de novo hair cells derive from FGF-active supporting cells. Our findings reveal that RA has a pivotal role in zebrafish hair cell regeneration by inducing supporting cell proliferation, and shed light on the underlying transcriptional mechanisms involved. This signaling pathway might be a promising approach for hearing recovery. SIGNIFICANCE STATEMENT Hair cells are the specialized mechanosensory cells of the inner ear that capture auditory and balance sensory input. Hair cells die after acoustic trauma, ototoxic drugs or aging diseases, leading to progressive hearing loss. Mammals, in contrast to zebrafish, lack the ability to regenerate hair cells. Here, we find that retinoic acid (RA) pathway is required for hair cell regeneration in vivo in the zebrafish inner ear and lateral line. RA pathway is activated very early upon hair cell loss, promotes cell proliferation of progenitor cells, and regulates two key genes, p27(kip) and sox2. Our results position RA as an essential signal for hair cell regeneration with relevance in future regenerative strategies in mammals.
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Romand R, Krezel W, Beraneck M, Cammas L, Fraulob V, Messaddeq N, Kessler P, Hashino E, Dollé P. Retinoic acid deficiency impairs the vestibular function. J Neurosci 2013; 33:5856-66. [PMID: 23536097 PMCID: PMC6705067 DOI: 10.1523/jneurosci.4618-12.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 01/28/2013] [Accepted: 02/21/2013] [Indexed: 11/21/2022] Open
Abstract
The retinaldehyde dehydrogenase 3 (Raldh3) gene encodes a major retinoic acid synthesizing enzyme and is highly expressed in the inner ear during embryogenesis. We found that mice deficient in Raldh3 bear severe impairment in vestibular functions. These mutant mice exhibited spontaneous circling/tilted behaviors and performed poorly in several vestibular-motor function tests. In addition, video-oculography revealed a complete loss of the maculo-ocular reflex and a significant reduction in the horizontal angular vestibulo-ocular reflex, indicating that detection of both linear acceleration and angular rotation were compromised in the mutants. Consistent with these behavioral and functional deficiencies, morphological anomalies, characterized by a smaller vestibular organ with thinner semicircular canals and a significant reduction in the number of otoconia in the saccule and the utricle, were consistently observed in the Raldh3 mutants. The loss of otoconia in the mutants may be attributed, at least in part, to significantly reduced expression of Otop1, which encodes a protein known to be involved in calcium regulation in the otolithic organs. Our data thus reveal a previously unrecognized role of Raldh3 in structural and functional development of the vestibular end organs.
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MESH Headings
- Aldehyde Dehydrogenase 1 Family
- Analysis of Variance
- Animals
- Behavioral Symptoms/etiology
- Behavioral Symptoms/genetics
- Embryo, Mammalian
- Eye Movements/drug effects
- Eye Movements/genetics
- Female
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Developmental/genetics
- Imaging, Three-Dimensional
- Isoenzymes/deficiency
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Knockout
- Microscopy, Electron, Transmission
- Motor Activity/drug effects
- Motor Activity/genetics
- Mutation/genetics
- Otolithic Membrane/pathology
- Pregnancy
- Prenatal Exposure Delayed Effects/physiopathology
- Reflex, Vestibulo-Ocular/drug effects
- Reflex, Vestibulo-Ocular/genetics
- Retinal Dehydrogenase/deficiency
- Swimming
- Tretinoin/pharmacology
- Vestibular Function Tests
- Vestibule, Labyrinth/physiopathology
- Vestibule, Labyrinth/ultrastructure
- Video Recording
- Vitamin A Deficiency/etiology
- Vitamin A Deficiency/pathology
- Walking/physiology
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Affiliation(s)
- Raymond Romand
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), BP 10142, Illkirch F-67404, France.
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6
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Cadot S, Frenz D, Maconochie M. A novel method for retinoic acid administration reveals differential and dose-dependent downregulation of Fgf3 in the developing inner ear and anterior CNS. Dev Dyn 2012; 241:741-58. [DOI: 10.1002/dvdy.23748] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2012] [Indexed: 12/23/2022] Open
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Braunstein EM, Monks DC, Aggarwal VS, Arnold JS, Morrow BE. Tbx1 and Brn4 regulate retinoic acid metabolic genes during cochlear morphogenesis. BMC DEVELOPMENTAL BIOLOGY 2009; 9:31. [PMID: 19476657 PMCID: PMC2700094 DOI: 10.1186/1471-213x-9-31] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 05/29/2009] [Indexed: 11/10/2022]
Abstract
BACKGROUND In vertebrates, the inner ear is comprised of the cochlea and vestibular system, which develop from the otic vesicle. This process is regulated via inductive interactions from surrounding tissues. Tbx1, the gene responsible for velo-cardio-facial syndrome/DiGeorge syndrome in humans, is required for ear development in mice. Tbx1 is expressed in the otic epithelium and adjacent periotic mesenchyme (POM), and both of these domains are required for inner ear formation. To study the function of Tbx1 in the POM, we have conditionally inactivated Tbx1 in the mesoderm while keeping expression in the otic vesicle intact. RESULTS Conditional mutants (TCre-KO) displayed malformed inner ears, including a hypoplastic otic vesicle and a severely shortened cochlear duct, indicating that Tbx1 expression in the POM is necessary for proper inner ear formation. Expression of the mesenchyme marker Brn4 was also lost in the TCre-KO. Brn4-;Tbx1+/-embryos displayed defects in growth of the distal cochlea. To identify a potential signal from the POM to the otic epithelium, expression of retinoic acid (RA) catabolizing genes was examined in both mutants. Cyp26a1 expression was altered in the TCre-KO, while Cyp26c1 showed reduced expression in both TCre-KO and Brn4-;Tbx1+/- embryos. CONCLUSION These results indicate that Tbx1 expression in the POM regulates cochlear outgrowth potentially via control of local retinoic acid activity.
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Affiliation(s)
- Evan M Braunstein
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA.
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8
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Sánchez-Guardado LÓ, Ferran JL, Mijares J, Puelles L, Rodríguez-Gallardo L, Hidalgo-Sánchez M. Raldh3gene expression pattern in the developing chicken inner ear. J Comp Neurol 2009; 514:49-65. [DOI: 10.1002/cne.21984] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Helyer R, Cacciabue-Rivolta D, Davies D, Rivolta MN, Kros CJ, Holley MC. A model for mammalian cochlear hair cell differentiation in vitro: effects of retinoic acid on cytoskeletal proteins and potassium conductances. Eur J Neurosci 2007; 25:957-73. [PMID: 17331193 DOI: 10.1111/j.1460-9568.2007.05338.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have established a model for the in-vitro differentiation of mouse cochlear hair cells and have used it to explore the influence of retinoic acid on proliferation, cytoskeletal proteins and voltage-gated potassium conductances. The model is based on the conditionally immortal cell line University of Sheffield/ventral otocyst-epithelial cell line clone 36 (US/VOT-E36), derived from ventral otic epithelial cells of the mouse at embryonic day 10.5 and transfected with a reporter for myosin VIIa. Retinoic acid did not increase cell proliferation but led to up-regulation of myosin VIIa and formation of prominent actin rings that gave rise to numerous large, linear actin bundles. Cells expressing myosin VIIa had larger potassium conductances and did not express the cyclin-dependent kinase inhibitor p27(kip1). US/VOT-E36 endogenously expressed the voltage-gated potassium channel alpha-subunits Kv1.3 and Kv2.1, which we subsequently identified in embryonic and neonatal hair cells in both auditory and vestibular sensory epithelia in vivo. These subunits could underlie the embryonic and neonatal delayed-rectifiers recorded in nascent hair cells in vivo. Kv2.1 was particularly prominent on the basolateral membrane of cochlear inner hair cells. Kv1.3 was distributed throughout all hair cells but tended to be localized to the cuticular plates. US/VOT-E36 recapitulates a coherent pattern of cell differentiation under the influence of retinoic acid and will provide a convenient model for screening the effects of other extrinsic factors on the differentiation of cochlear epithelial cell types in vitro.
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Affiliation(s)
- R Helyer
- Department of Biomedical Science, Addison Building, Western Bank, Sheffield, UK
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Romand R, Kondo T, Fraulob V, Petkovich M, Dollé P, Hashino E. Dynamic expression of retinoic acid-synthesizing and -metabolizing enzymes in the developing mouse inner ear. J Comp Neurol 2006; 496:643-54. [PMID: 16615129 PMCID: PMC2845518 DOI: 10.1002/cne.20936] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Retinoic acid signaling plays essential roles in morphogenesis and neural development through transcriptional regulation of downstream target genes. It is believed that the balance between the activities of synthesizing and metabolizing enzymes determines the amount of active retinoic acid to which a developing tissue is exposed. In this study, we investigated spatiotemporal expression patterns of four synthesizing enzymes, the retinaldehyde dehydrogenases 1, 2, 3, and 4 (Raldh1, Raldh2, Raldh3, and Raldh4) and two metabolizing enzymes (Cyp26A1 and Cyp26B1) in the embryonic and postnatal mouse inner ear by using quantitative reverse transcriptase polymerase chain reaction (RT-PCR), in situ hybridization, and Western blot analysis. Quantitative RT-PCR analysis and Western blot data revealed that the expression of CYP26s was much higher than that of Raldhs at early embryonic ages but that Cyp26 expression was downregulated during embryonic development. Conversely, the expression levels of Raldh2 and -3 increased during development and were significantly higher than the Cyp26 levels at postnatal day 20. At this age, Raldh3 was expressed predominantly in the cochlea, whereas Raldh2 was present in the vestibular end organ. At early embryonic stages, as observed by in situ hybridization, the synthesizing enzymes were expressed only in the dorsoventral epithelium of the otocyst, whereas the metabolizing enzymes were present mainly in mesenchymal cells surrounding the otic epithelium. At later stages, Raldh2, Raldh3, and Cyp26B1 were confined to the stria vascularis, spiral ganglion, and supporting cells in the cochlear and vestibular epithelia, respectively. The downregulation of Cyp26s and the upregulation of Raldhs after birth during inner ear maturation suggest tissue changes in the sensitivity to retinoic acid concentrations.
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Abstract
The inner ear originates from an embryonic ectodermal placode and rapidly develops into a three-dimensional structure (the otocyst) through complex molecular and cellular interactions. Many genes and their products are involved in inner ear induction, organogenesis, and cell differentiation. Retinoic acid (RA) is an endogenous signaling molecule that may play a role during different phases of inner ear development, as shown from pathological observations. To gain insight into the function of RA during inner ear development, we have investigated the spatio-temporal expression patterns of major components of RA signaling pathway, including cellular retinoic acid binding proteins (CRABPs), cellular retinoid binding proteins (CRBPs), retinaldehyde dehydrogenases (RALDHs), catabolic enzymes (CYP26s), and nuclear receptors (RARs). Although the CrbpI, CrabpI, and -II genes are specifically expressed in the inner ear throughout development, loss-of-function studies have revealed that these proteins are dispensable for inner development and function. Several Raldh and Cyp26 gene transcripts are expressed at embryological day (E) 9.0-9.5 in the otocyst and show mainly complementary distributions in the otic epithelium and mesenchyme during following stages. From Western blot, RT-PCR, and in situ hybridization analysis, there is a low expression of Raldhs in the early otocyst at E9, while Cyp26s are strongly expressed. During the following days, there is an up-regulation of Raldhs and a down-regulation for Cyp26s. Specific RA receptor (Rar and Rxr) genes are expressed in the otocyst and during further development of the inner ear. At the otocyst stage, most of the components of the retinoid pathway are present, suggesting that the embryonic inner ear might act as an autocrine system, which is able to synthesize and metabolize RA necessary for its development. We propose a model in which two RA-dependent pathways may control inner ear ontogenesis: one indirect with RA from somitic mesoderm acting to regulate gene expression within the hindbrain neuroepithelium, and another with RA acting directly on the otocyst. Current evidence suggests that RA may regulate several genes involved in mesenchyme-epithelial interactions, thereby controlling inner ear morphogenesis. Our investigations suggest that RA signaling is a critical component not only of embryonic development, but also of postnatal maintenance of the inner ear.
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Affiliation(s)
- Raymond Romand
- Institut Clinique de la Souris and Institut de Génétique et de Biologie Moléculaire et cellulaire, B.P. 10142, 67404 Illkirch Cedex, France.
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12
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Choo D, Ward J, Reece A, Dou H, Lin Z, Greinwald J. Molecular mechanisms underlying inner ear patterning defects in kreisler mutants. Dev Biol 2006; 289:308-17. [PMID: 16325169 DOI: 10.1016/j.ydbio.2005.10.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 10/04/2005] [Accepted: 10/06/2005] [Indexed: 10/25/2022]
Abstract
Prior studies have shown that kreisler mutants display early inner ear defects that are related to abnormal hindbrain development and signaling. These defects in kreisler mice have been linked to mutation of the kr/mafB gene. To investigate potential relevance of kr/mafB and abnormal hindbrain development in inner ear patterning, we analyzed the ear morphogenesis in kreisler mice using a paint-fill technique. We also examined the expression patterns of a battery of genes important for normal inner ear patterning and development. Our results indicate that the loss of dorsal otic structures such as the endolymphatic duct and sac is attributable to the downregulation of Gbx2, Dlx5 and Wnt2b in the dorsal region of the otocyst. In contrast, the expanded expression domain of Otx2 in the ventral otic region likely contributes to the cochlear phenotype seen in kreisler mutants. Sensory organ development is also markedly disrupted in kreisler mutants. This pattern of defects and gene expression changes is remarkably similar to that observed in Gbx2 mutants. Taken together, the data show an important role for hindbrain cues, and indirectly, kr/mafB, in guiding inner ear morphogenesis. The data also identify Gbx2, Dlx5, Wnt2b and Otx2 as key otic genes ultimately affected by perturbation of the kr/mafB-hindbrain pathway.
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Affiliation(s)
- Daniel Choo
- Department of Otolaryngology Head and Neck Surgery, Center for Hearing and Deafness Research, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, OH 45229-3039, USA.
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13
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Kil SH, Streit A, Brown ST, Agrawal N, Collazo A, Zile MH, Groves AK. Distinct roles for hindbrain and paraxial mesoderm in the induction and patterning of the inner ear revealed by a study of vitamin-A-deficient quail. Dev Biol 2005; 285:252-71. [PMID: 16039643 DOI: 10.1016/j.ydbio.2005.05.044] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 05/25/2005] [Accepted: 05/25/2005] [Indexed: 01/22/2023]
Abstract
The hindbrain and cranial paraxial mesoderm have been implicated in the induction and patterning of the inner ear, but the precise role of the two tissues in these processes is still not clear. We have addressed these questions using the vitamin-A-deficient (VAD) quail model, in which VAD embryos lack the posterior half of the hindbrain that normally lies next to the inner ear. Using a battery of molecular markers, we show that the anlagen of the inner ear, the otic placode, is induced in VAD embryos in the absence of the posterior hindbrain. By performing grafting and ablation experiments in chick embryos, we also show that cranial paraxial mesoderm which normally lies beneath the presumptive otic placode is necessary for otic placode induction and that paraxial mesoderm from other locations cannot induce the otic placode. Two members of the fibroblast growth factor family, FGF3 and FGF19, continue to be expressed in this mesodermal population in VAD embryos, and these may be responsible for otic placode induction in the absence of the posterior hindbrain. Although the posterior hindbrain is not required for otic placode induction in VAD embryos, the subsequent patterning of the inner ear is severely disrupted. Several regional markers of the inner ear, such as Pax2, EphA4, SOHo1 and Wnt3a, are incorrectly expressed in VAD otocysts, and the sensory patches and vestibulo-acoustic ganglia are either greatly reduced or absent. Exogenous application of retinoic acid prior to 30 h of development is able rescue the VAD phenotype. By performing such rescue experiments before and after 30 h of development, we show that the inner ear defects of VAD embryos correlate with the absence of the posterior hindbrain. These results show that induction and patterning of the inner ear are governed by separate developmental processes that can be experimentally uncoupled from each other.
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Affiliation(s)
- Sung-Hee Kil
- Gonda Department of Cell and Molecular Biology, House Ear Institute, 2100 West 3rd Street, Los Angeles, CA 90057, USA
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Butts SC, Liu W, Li G, Frenz DA. Transforming growth factor-beta1 signaling participates in the physiological and pathological regulation of mouse inner ear development by all-trans retinoic acid. ACTA ACUST UNITED AC 2005; 73:218-28. [PMID: 15799023 DOI: 10.1002/bdra.20128] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND Retinoic acid (RA) is a vitamin A derivative that participates in patterning and regulation of inner ear development. Either excess RA or RA deficiency during a critical stage of inner ear development can produce teratogenic effects. Previous studies have shown that in utero exposure of the developing mouse inner ear to a high dose of all-trans RA (atRA) results in severe malformations of the inner ear that are associated with diminished levels of endogenous transforming growth factor-beta1 (TGF-beta(1)) protein. METHODS In this study, the effects of a teratogenic level of atRA on levels and patterns of expression of TGFbeta receptor II (TGFbetaRII) and Smad2, a downstream component of the TGFbeta signal transduction pathway, are investigated in the developing mouse inner ear. The expression pattern of endogenous RA receptor alpha (RARalpha) and the ability of an RARalpha(1)-specific antisense oligonucleotide (AS) to modulate otic capsule chondrogenesis are demonstrated in the inner ear and in culture. RESULTS Endogenous TGFbetaRII and Smad2 are downregulated in the inner ear following in utero atRA treatment. In addition, a reduction in endogenous TGFbeta(1) and a marked suppression of chondrogenesis occur in RARalpha(1) AS-treated cultures in comparison to untreated or oligonucleotide-treated control cultures. This chondrogenic suppression can be partially overcome by supplementation of RARalpha(1) AS-treated cultures with exogenous TGFbeta(1) protein. CONCLUSIONS Our findings support a role for TGFbeta in the physiological and pathological effects of RA on inner ear development.
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MESH Headings
- Abnormalities, Drug-Induced
- Animals
- Chondrogenesis/genetics
- Chondrogenesis/physiology
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Down-Regulation
- Ear, Inner/abnormalities
- Ear, Inner/drug effects
- Ear, Inner/embryology
- Epithelium/immunology
- Female
- Gene Expression/drug effects
- Male
- Mesoderm/immunology
- Mice
- Oligonucleotides, Antisense/pharmacology
- Pregnancy
- Protein Serine-Threonine Kinases
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Retinoic Acid/analysis
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/metabolism
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Retinoic Acid Receptor alpha
- Signal Transduction
- Smad2 Protein
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transforming Growth Factor beta/physiology
- Transforming Growth Factor beta1
- Tretinoin/toxicity
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Affiliation(s)
- Sydney C Butts
- Department of Otolaryngology, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY 10461, USA
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15
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Lefebvre P, Martin PJ, Flajollet S, Dedieu S, Billaut X, Lefebvre B. Transcriptional activities of retinoic acid receptors. VITAMINS AND HORMONES 2005; 70:199-264. [PMID: 15727806 DOI: 10.1016/s0083-6729(05)70007-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vitamin A derivatives plays a crucial role in embryonic development, as demonstrated by the teratogenic effect of either an excess or a deficiency in vitamin A. Retinoid effects extend however beyond embryonic development, and tissue homeostasis, lipid metabolism, cellular differentiation and proliferation are in part controlled through the retinoid signaling pathway. Retinoids are also therapeutically effective in the treatment of skin diseases (acne, psoriasis and photoaging) and of some cancers. Most of these effects are the consequences of retinoic acid receptors activation, which triggers transcriptional events leading either to transcriptional activation or repression of retinoid-controlled genes. Synthetic molecules are able to mimic part of the biological effects of the natural retinoic acid receptors, all-trans retinoic acid. Therefore, retinoic acid receptors are considered as highly valuable therapeutic targets and limiting unwanted secondary effects due to retinoid treatment requires a molecular knowledge of retinoic acid receptors biology. In this review, we will examine experimental evidence which provide a molecular basis for the pleiotropic effects of retinoids, and emphasize the crucial roles of coregulators of retinoic acid receptors, providing a conceptual framework to identify novel therapeutic targets.
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Affiliation(s)
- Philippe Lefebvre
- INSERM U459 and Ligue Nationale Contre le Cancer, Faculté de Médecine de Lille, 59045 Lille cedex, France
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16
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Germiller JA, Smiley EC, Ellis AD, Hoff JS, Deshmukh I, Allen SJ, Barald KF. Molecular characterization of conditionally immortalized cell lines derived from mouse early embryonic inner ear. Dev Dyn 2004; 231:815-27. [PMID: 15517566 DOI: 10.1002/dvdy.20186] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Inner ear sensory hair cells (HCs), supporting cells (SCs), and sensory neurons (SNs) are hypothesized to develop from common progenitors in the early embryonic otocyst. Because little is known about the molecular signals that control this lineage specification, we derived a model system of early otic development: conditionally immortalized otocyst (IMO) cell lines from the embryonic day 9.5 Immortomouse. This age is the earliest stage at which the otocyst can easily be separated from surrounding mesenchymal, nervous system, and epithelial cells. At 9.5 days post coitum, there are still pluripotent cells in the otocyst, allowing for the eventual identification of both SN and HC precursors--and possibly an elusive inner ear stem cell. Cell lines derived from primitive precursor cells can also be used as blank canvases for transfections of genes that can affect lineage decisions as the cells differentiate. It is important, therefore, to characterize the "baseline state" of these cell lines in as much detail as possible. We characterized seven representative "precursor-like" IMO cell populations and the uncloned IMO cells, before cell sorting, at the molecular level by polymerase chain reaction (PCR) and immunocytochemistry (IHC), and one line (IMO-2B1) in detail by real-time quantitative PCR and IHC. Many of the phenotypic markers characteristic of differentiated HCs or SCs were detected in IMO-2B1 proliferating cells, as well as during differentiation for up to 30 days in culture. These IMO cell lines represent a unique model system for studying early stages of inner ear development and determining the consequences of affecting key molecular events in their differentiation.
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Affiliation(s)
- John A Germiller
- Department of Cell and Developmental Biology, Program in Cell and Molecular Biology, Program in Neuroscience, University of Michigan, Ann Arbor, Michigan 48109-0616, USA
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17
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Abstract
The highly orchestrated processes that generate the vertebrate inner ear from the otic placode provide an excellent and circumscribed testing ground for fundamental cellular and molecular mechanisms of development. The recent pace of discovery in developmental auditory biology has been unusually rapid,with hundreds of papers published in the past 4 years. This review summarizes studies addressing several key issues that shape our current thinking about inner ear development, with particular emphasis on early patterning events,sensory hair cell specification and planar cell polarity.
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Affiliation(s)
- Kate F Barald
- Department of Cell and Developmental Biology, Program in Neuroscience, Cell and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109-0616, USA
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18
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Chang W, Brigande JV, Fekete DM, Wu DK. The development of semicircular canals in the inner ear: role of FGFs in sensory cristae. Development 2004; 131:4201-11. [PMID: 15280215 DOI: 10.1242/dev.01292] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the vertebrate inner ear, the ability to detect angular head movements lies in the three semicircular canals and their sensory tissues, the cristae. The molecular mechanisms underlying the formation of the three canals are largely unknown. Malformations of this vestibular apparatus found in zebrafish and mice usually involve both canals and cristae. Although there are examples of mutants with only defective canals, few mutants have normal canals without some prior sensory tissue specification, suggesting that the sensory tissues,cristae, might induce the formation of their non-sensory components, the semicircular canals. We fate-mapped the vertical canal pouch in chicken that gives rise to the anterior and posterior canals, using a fluorescent,lipophilic dye (DiI), and identified a canal genesis zone adjacent to each prospective crista that corresponds to the Bone morphogenetic protein 2 (Bmp2)-positive domain in the canal pouch. Using retroviruses or beads to increase Fibroblast Growth Factors (FGFs) for gain-of-function and beads soaked with the FGF inhibitor SU5402 for loss-of-function experiments,we show that FGFs in the crista promote canal development by upregulating Bmp2. We postulate that FGFs in the cristae induce a canal genesis zone by inducing/upregulating Bmp2 expression. Ectopic FGF treatments convert some of the cells in the canal pouch from the prospective common crus to a canal-like fate. Thus, we provide the first molecular evidence whereby sensory organs direct the development of the associated non-sensory components, the semicircular canals, in vertebrate inner ears.
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Affiliation(s)
- Weise Chang
- National Institute on Deafness and Other Communication Disorders, Rockville, MD 20850, USA
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19
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Pilipenko VV, Reece A, Choo DI, Greinwald JH. Genomic organization and expression analysis of the murine Fam3c gene. Gene 2004; 335:159-68. [PMID: 15194199 DOI: 10.1016/j.gene.2004.03.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Revised: 02/02/2004] [Accepted: 03/29/2004] [Indexed: 10/26/2022]
Abstract
Previously, we identified FAM3C as a candidate gene for autosomal recessive nonsyndromic hearing loss locus 17 (DFNB17). This gene has since been found to be a member of a cytokine-like gene family, but its function has not been determined. The purpose of this study was thus to elucidate the gene structure and pattern of expression, providing information that might allow a hypothesis to be developed about FAM3C function of in the inner ear. To do this we analyzed its mouse ortholog, Fam3c. Fam3c was found to be ubiquitously expressed in all analyzed tissues, and had two major transcript variants presumed to result from an alternative use of two distinct polyadenylation signals. In situ hybridization experiments revealed a predominant Fam3c pattern of expression in the nonsensory epithelium of the growing semicircular canals at embryonic day (E) 15.5. This expression pattern resembles the known pattern of the Nkx5 homeobox genes. Analysis of the Fam3c promoter region demonstrated a putative Nkx5.1 binding site. Based on our findings, we hypothesize that Fam3c may be a downstream target gene for the Nkx5.1 transcription factor, and may thus be involved in cell differentiation and proliferation during inner ear embryogenesis. Additionally, analyses of putative amino acid sequences of FAM3C orthologous proteins showed that their primary and secondary structures and overall topology were highly conserved. Further study is underway to determine the role of FAM3C in inner ear development.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Binding Sites/genetics
- Blotting, Northern
- Conserved Sequence/genetics
- Cytokines
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Ear, Inner/embryology
- Ear, Inner/metabolism
- Gene Expression Profiling
- Gene Expression Regulation, Developmental
- Genes/genetics
- Humans
- In Situ Hybridization
- Mice
- Molecular Sequence Data
- Neoplasm Proteins
- Proteins/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Regulatory Sequences, Nucleic Acid/genetics
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Time Factors
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Affiliation(s)
- Valentina V Pilipenko
- Center for Hearing and Deafness Research, Division of Otolaryngology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
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20
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zur Nieden NI, Kempka G, Ahr HJ. Molecular multiple endpoint embryonic stem cell test--a possible approach to test for the teratogenic potential of compounds. Toxicol Appl Pharmacol 2004; 194:257-69. [PMID: 14761682 DOI: 10.1016/j.taap.2003.09.019] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2003] [Accepted: 09/23/2003] [Indexed: 01/09/2023]
Abstract
The embryonic stem cell test (EST) examines the cytotoxicity of chemical compounds on embryonic stem (ES) cells and 3T3.A31 fibroblasts. Additionally, the EST measures the ability of ES cells to differentiate into contracting cardiomyocytes following drug exposure. In this study, we introduce new endpoints to obtain a molecular multiple endpoint EST (mme-EST), enabling the identification of potential chemical effects on osteogenic, chondrogenic and neural differentiation in addition to the traditional endpoint of cardiomyocyte differentiation. Six compounds in three classes with known teratogenic in vivo potential were assayed with the mme-EST in a pilot study: penicillin G (non-teratogenic), 5-fluorouracil and retinoic acid (strongly teratogenic), diphenylhydantoin, valproic acid and thalidomide (moderately teratogenic). While the traditional EST measures a morphological endpoint, we included molecular markers of differentiation as endpoints. With the mme-EST, every compound could be classified correctly according to its known teratogenic potential in vivo. Penicillin G, 5-fluorouracil and diphenylhydantoin inhibited differentiation of all endpoints equally. Interestingly, valproic acid showed the strongest inhibition of neural differentiation, while thalidomide specifically inhibited osteogenic development. Retinoic acid, on the other hand, supported neural but inhibited chondrogenic and osteogenic differentiation concentration-dependently. Valproic acid and thalidomide, classified incorrectly with the established EST model, were classified correctly with the mme-EST according to their effects on specific endpoints. This pilot study indicates that the predictive value of the EST may be enhanced by including further differentiation endpoints.
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Affiliation(s)
- N I zur Nieden
- Research Toxicology, Bayer AG, Aprather Weg, D-42096 Wuppertal, Germany.
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21
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Abstract
The vertebrate inner ear is a marvel of structural and functional complexity, which is all the more remarkable because it develops from such a simple structure, the otic placode. Analysis of inner ear development has long been a fascination of experimental embryologists, who sought to understand cellular mechanisms of otic placode induction. More recently, however, molecular and genetic approaches have made the inner ear a useful model system for studying a much broader range of basic developmental mechanisms, including cell fate specification and differentiation, axial patterning, epithelial morphogenesis, cytoskeletal dynamics, stem cell biology, neurobiology, physiology, etc. Of course, there has also been tremendous progress in understanding the functions and processes peculiar to the inner ear. The goal of this review is to recount how historical approaches have shaped our understanding of the signaling interactions controlling early otic development; to discuss how new findings have led to fundamental new insights; and to point out new problems that need to be resolved in future research.
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Affiliation(s)
- Bruce B Riley
- Biology Department, Texas A&M University, College Station, TX 77843-3258, USA.
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22
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Merves M, Krane CM, Dou H, Greinwald JH, Menon AG, Choo D. Expression of aquaporin 1 and 5 in the developing mouse inner ear and audiovestibular assessment of an Aqp5 null mutant. J Assoc Res Otolaryngol 2003; 4:264-75. [PMID: 12943377 PMCID: PMC3202717 DOI: 10.1007/s10162-002-3033-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Accepted: 11/07/2002] [Indexed: 10/26/2022] Open
Abstract
To examine the potential roles of aquaporins 1 and 5 (AQP1 and AQP5, respectively) in inner ear development and function, we defined their spatial and temporal expression patterns in the developing mouse inner ear and examined the morphologic and physiologic effects of loss of Aqp5 function. Standard in situ hybridization (ISH) and immunohistochemical (IHC) assays were used for expression studies with routine morphologic, behavioral, and physiologic assessments of hearing and balance in Aqp5 null mutant mice. AQP1 was first detected at embryonic day 10.5 (E10.5) in the otocyst but eventually localized to specific nonsensory portions of the inner ear and connective tissue cells surrounding the membranous labyrinth. AQP5 displayed specific cochlear expression, first detectable at E15.5 in the nonsensory epithelium and later restricted to the lateral wall of the cochlear duct near the spiral prominence. AQP5 expression continued through postnatal periods with a change of expression domain to the stria vascularis between postnatal day 7 (P7) and P14. By in situ hybridization and immunohistochemical techniques, subtle differences between transcript and protein expression patterns were noted for both AQP1 and 5. Although AQP5 is dynamically expressed in the developing mouse inner ear, adult Aqp5 knockout mice show normal hearing when tested and normal inner ear structural development. These results suggest redundant or alternative mechanisms that likely regulate water homeostasis in the developing and mature inner ear.
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MESH Headings
- Aging/metabolism
- Animals
- Animals, Newborn/growth & development
- Animals, Newborn/metabolism
- Aquaporin 1
- Aquaporin 5
- Aquaporins/deficiency
- Aquaporins/metabolism
- Behavior, Animal
- Ear, Inner/embryology
- Ear, Inner/metabolism
- Ear, Inner/pathology
- Ear, Inner/physiopathology
- Embryo, Mammalian/metabolism
- Embryonic and Fetal Development
- Evoked Potentials, Auditory, Brain Stem
- Hearing
- Membrane Proteins
- Mice
- Mice, Inbred Strains
- Mice, Knockout
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Affiliation(s)
- Michele Merves
- Department of Pediatric Otolaryngology, Center for Hearing and Deafness Research, Cincinnati, OH 45229, USA
| | - Carissa M. Krane
- Department of Biology, University of Dayton, Dayton, OH 45404, USA
| | - Hongwei Dou
- Department of Pediatric Otolaryngology, Center for Hearing and Deafness Research, Cincinnati, OH 45229, USA
| | - John H. Greinwald
- Department of Pediatric Otolaryngology, Center for Hearing and Deafness Research, Cincinnati, OH 45229, USA
| | - Anil G. Menon
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Daniel Choo
- Department of Pediatric Otolaryngology, Center for Hearing and Deafness Research, Cincinnati, OH 45229, USA
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23
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Abstract
Acid-base homeostasis of endolymph is thought to be essential for normal inner ear function. This assumption was supported by clinical data from individuals affected by autosomal recessive distal renal tubular acidosis with sensorineural hearing loss. This recessive syndrome was recently demonstrated to be due to mutations in the gene encoding the B1 subunit of H(+)-ATPase (ATP6B1). To examine the potential roles of H(+)-ATPase B1 subunit in inner ear development and function, we defined its spatial and temporal expression patterns in the developing mouse inner ear and examined the morphologic and physiologic effects of loss of its function. Standard in situ hybridization was used for the expression study with routine morphologic and physiologic assessments of hearing and balance in H(+)-ATPase B1 subunit (Atp6b1) null mutant mice. Atp6b1 mRNA was first detected at embryonic day 11.5 (E11.5) in the endolymphatic duct epithelia. From E16.5 onward, Atp6b1 was also observed in the presumptive interdental cell layer of the spiral limbus in the cochlea. Auditory brainstem response tests revealed normal hearing in mice lacking Atp6b1. The inner ears of these mice develop normally and show no overt morphological abnormalities. Our data demonstrate that Atp6b1 is not critical for normal inner ear development or normal inner ear function in mice and suggest that other proton-transporting mechanisms or pH buffering systems must allow the mouse inner ear to compensate for lack of normal Atp6b1 activity.
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Affiliation(s)
- Hongwei Dou
- Center for Hearing and Deafness Research, Department of Pediatric Otolaryngology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA
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24
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Thompson DL, Gerlach-Bank LM, Barald KF, Koenig RJ. Retinoic acid repression of bone morphogenetic protein 4 in inner ear development. Mol Cell Biol 2003; 23:2277-86. [PMID: 12640113 PMCID: PMC150746 DOI: 10.1128/mcb.23.7.2277-2286.2003] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2002] [Revised: 01/02/2003] [Accepted: 01/08/2003] [Indexed: 11/20/2022] Open
Abstract
Bone morphogenetic protein 4 (BMP4) and retinoic acid are important for normal development of the inner ear, but whether they are linked mechanistically is not known. BMP4 antagonists disrupt semicircular canal formation, as does exposure to retinoic acid. We demonstrate that retinoic acid directly down-regulates BMP4 transcription in a mouse inner ear-derived cell line, and we identify a novel promoter in the second intron of the BMP4 gene that is a target of this regulation both in the cell line and in the mouse embryonic inner ear in vivo. The importance of this down-regulation is demonstrated in chicken embryos by showing that the retinoic acid effect on semicircular canal development can be overcome by exogenous BMP4.
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MESH Headings
- Animals
- Benzoates/pharmacology
- Bone Morphogenetic Protein 4
- Bone Morphogenetic Proteins/antagonists & inhibitors
- Bone Morphogenetic Proteins/pharmacology
- Bone Morphogenetic Proteins/physiology
- Cell Line
- Chick Embryo
- Ear, Inner/cytology
- Ear, Inner/drug effects
- Ear, Inner/embryology
- Ear, Inner/metabolism
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Developmental/physiology
- Introns
- Mice
- Promoter Regions, Genetic/physiology
- RNA/metabolism
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/metabolism
- Retinoic Acid Receptor alpha
- Retinoids/pharmacology
- Transcription, Genetic/physiology
- Tretinoin/pharmacology
- Tretinoin/physiology
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Affiliation(s)
- Deborah L Thompson
- Department of Internal Medicine, Endocrinology Division, University of Michigan, Ann Arbor, Michigan 48109-0678, USA
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25
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Affiliation(s)
- Raymond Romand
- Institut Clinique de la Souris, 67404 Illkirch Cedex, France
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26
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Romand R, Hashino E, Dollé P, Vonesch JL, Chambon P, Ghyselinck NB. The retinoic acid receptors RARalpha and RARgamma are required for inner ear development. Mech Dev 2002; 119:213-23. [PMID: 12464434 DOI: 10.1016/s0925-4773(02)00385-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To define the signal transduction pathway of retinoic acid during inner ear development, we analyzed the expression patterns of transcripts encoding the three retinoic acid receptors (RARalpha, beta, and gamma) and related them to phenotypes resulting from single or compound inactivation of these nuclear receptors. The expression of all three RARs was observed in the developing mouse otocyst as early as embryonic day 10.5 (E10.5)-E12.5 and continued into adulthood. Expression domains of the three RAR receptors, however, were largely non-overlapping: RARalpha was predominantly expressed in the developing sensory epithelium, RARbeta in inner ear mesenchymal tissues and RARgamma in the differentiating otic capsule. In the adult, RARalpha and RARgamma transcripts were found in the organ of Corti and the spiral ganglion, whereas RARbeta transcripts were localized in mesenchyme-derived tissues. RARalpha, beta, and gamma null mutant mice, as well as RARalpha/RARbeta and RARbeta/RARgamma combined null fetuses, did not present any noticeable morphological abnormalities in the inner ear. In contrast, RARalpha/RARgamma null mutants displayed a severe hypoplasia of the otocyst that was already visible at E10.5 without any visible endolymphatic duct. The hypoplastic otocyst in RARalpha/RARgamma null mutants was characterized by impaired chondrocyte differentiation and neural development. After the second week of gestation, these mutant fetuses lacked all of the semi-circular canals and the endolymphatic duct and displayed strong anomalies in the inner ear structures. The morphological deficits were generally more severe in the cochlear portion than in the vestibular portion of the inner ear. Altogether, these results demonstrate that RARalpha and RARgamma play an essential role in the initial differentiation of otic placode derivatives, whereas RARbeta plays a minimal role in this process.
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Affiliation(s)
- Raymond Romand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis Pasteur, Collège de France, B.P. 10142, 67404 Illkirch Cedex, France.
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27
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Abstract
Inner ear induction, like induction of other tissues examined in recent years, is likely to be comprised of several stages. The process begins during gastrulation when the ectoderm is competent to respond to induction. It appears that a signal from the endomesoderm underlying the otic area during gastrulation initiates induction complemented by a signal from presumptive neural tissue. By the neural plate stage, a region of ectoderm outside the neural plate is "biased" toward ear formation; this process may be part of a more general "placodal" bias shared by several sensory tissues. Induction continues during neurulation when a signal from neural tissue (possibly augmented by mesoderm underlying the otic area) results in ectoderm committed to otic vesicle formation at the time of neural tube closure. Studies on several gene families implicate them in the ear determination process. Fibroblast Growth Factor (FGF) family members are clearly involved in induction: FGFs are appropriately expressed for such a role, and have been shown to be essential for inner ear development. FGFs also have inductive activity, although it is not clear if they are sufficient for ear induction. Activation of transcription factors in the otic ectoderm, for example, by Pax gene family members, provides evidence for important changes in the responding ectoderm beginning during gastrulation and continuing through specification at the end of neurulation, although few functional tests have defined the role of these genes in determination. The challenge remains to merge embryologic data with gene function studies to develop a clear model for the molecular basis of inner ear induction.
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Affiliation(s)
- Selina Noramly
- Department of Biology, University of Virginia, Gilmer Hall, Charlottesville, Virginia 22904, USA
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28
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Pasqualetti M, Neun R, Davenne M, Rijli FM. Retinoic acid rescues inner ear defects in Hoxa1 deficient mice. Nat Genet 2001; 29:34-9. [PMID: 11528388 DOI: 10.1038/ng702] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Little is known about the genetic pathways involved in the early steps of inner ear morphogenesis. Hoxa1 is transiently expressed in the developing hindbrain; its targeted inactivation in mice results in severe abnormalities of the otic capsule and membranous labyrinth. Here we show that a single maternal administration of a low dose of the vitamin A metabolite retinoic acid is sufficient to compensate the requirement for Hoxa1 function. It rescues cochlear and vestibular defects in mutant fetuses without affecting the development of the wildtype fetuses. These results identify a temporal window of susceptibility to retinoids that is critical for mammalian inner ear specification, and provide the first evidence that a subteratogenic dose of vitamin A derivative can be effective in rescuing a congenital defect in the mammalian embryo.
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Affiliation(s)
- M Pasqualetti
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Collège de France, BP 163-67404 Illkirch Cedex, C.U. de Strasbourg, France
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29
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Romand R, Albuisson E, Niederreither K, Fraulob V, Chambon P, Dollé P. Specific expression of the retinoic acid-synthesizing enzyme RALDH2 during mouse inner ear development. Mech Dev 2001; 106:185-9. [PMID: 11472854 DOI: 10.1016/s0925-4773(01)00447-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Retinoid binding proteins and nuclear receptors are expressed in the developing mouse inner ear. Here, we report that the retinaldehyde dehydrogenase 2 (Raldh2) gene, whose product is involved in the enzymatic generation of retinoic acid (RA), exhibits a restricted expression pattern during mouse inner ear ontogenesis. The Raldh2 gene is first expressed at embryonic day (E) 10.5 in a V-shaped medio-dorsal region of the otocyst outer epithelium, which evolves as two separate domains upon otocyst morphogenesis. At E14.5, Raldh2 is expressed in two areas of the utricle epithelium and specific regions of the saccule and cochlear mesenchyme. Later, Raldh2 transcripts are restricted to two cochlear areas, the stria vascularis and Reissner membrane. Raldh2 mesenchymal expression did not correlate with migrating neural crest-derived melanoblasts. These restricted expression domains may correspond to specific sites of RA synthesis during inner ear morphogenesis.
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Affiliation(s)
- R Romand
- Laboratoire de Neurobiologie, Université Blaise Pascal, 63177 Cedex, Aubière, France.
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Brigande JV, Kiernan AE, Gao X, Iten LE, Fekete DM. Molecular genetics of pattern formation in the inner ear: do compartment boundaries play a role? Proc Natl Acad Sci U S A 2000; 97:11700-6. [PMID: 11050198 PMCID: PMC34338 DOI: 10.1073/pnas.97.22.11700] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The membranous labyrinth of the inner ear establishes a precise geometrical topology so that it may subserve the functions of hearing and balance. How this geometry arises from a simple ectodermal placode is under active investigation. The placode invaginates to form the otic cup, which deepens before pinching off to form the otic vesicle. By the vesicle stage many genes expressed in the developing ear have assumed broad, asymmetrical expression domains. We have been exploring the possibility that these domains may reflect developmental compartments that are instrumental in specifying the location and identity of different parts of the ear. The boundaries between compartments are proposed to be the site of inductive interactions required for this specification. Our work has shown that sensory organs and the endolymphatic duct each arise near the boundaries of broader gene expression domains, lending support to this idea. A further prediction of the model, that the compartment boundaries will also represent lineage-restriction compartments, is supported in part by fate mapping the otic cup. Our data suggest that two lineage-restriction boundaries intersect at the dorsal pole of the otocyst, a convergence that may be critical for the specification of endolymphatic duct outgrowth. We speculate that the patterning information necessary to establish these two orthogonal boundaries may emanate, in part, from the hindbrain. The compartment boundary model of ear development now needs to be tested through a variety of experimental perturbations, such as the removal of boundaries, the generation of ectopic boundaries, and/or changes in compartment identity.
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Affiliation(s)
- J V Brigande
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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Frenz DA, Liu W. Treatment with all-trans-retinoic acid decreases levels of endogenous TGF-beta(1) in the mesenchyme of the developing mouse inner ear. TERATOLOGY 2000; 61:297-304. [PMID: 10716749 DOI: 10.1002/(sici)1096-9926(200004)61:4<297::aid-tera9>3.0.co;2-h] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Previous studies have shown that in utero exposure of the mouse embryo to high doses of all-trans-retinoic acid (atRA) produces defects of the developing inner ear and its surrounding cartilaginous capsule, while exposure of cultured periotic mesenchyme plus otic epithelium to high doses of exogenous atRA results in an inhibition of otic capsule chondrogenesis. METHODS In this study, we examine the effects of atRA exposure on the endogenous expression of transforming growth factor-beta(1) (TGF-beta(1)), a signaling molecule that mediates the epithelial-mesenchymal interactions that guide the development of the capsule of the inner ear. RESULTS Our results demonstrate a marked reduction in immunostaining for TGF-beta(1) in the periotic mesenchyme of atRA-exposed embryos of age E10.5 and E12 days in comparison with control specimens. Consistent with these in vivo findings, high-density cultures of E10.5 periotic mesenchyme plus otic epithelium, treated with doses of atRA that suppress chondrogenesis, showed significantly decreased levels of TGF-beta(1), as compared with TGF-beta(1) levels in untreated control cultures. Furthermore, we demonstrate a rescue of cultured periotic mesenchyme plus otic epithelium from atRA-induced chondrogenic suppression by supplementation of cultures with excess TGF-beta(1). CONCLUSIONS Our results support the hypothesis that TGF-beta(1) plays a role in mechanisms of atRA teratogenicity during inner ear development.
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Affiliation(s)
- D A Frenz
- Department of Otolaryngology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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Niederreither K, Vermot J, Schuhbaur B, Chambon P, Dollé P. Retinoic acid synthesis and hindbrain patterning in the mouse embryo. Development 2000; 127:75-85. [PMID: 10654602 DOI: 10.1242/dev.127.1.75] [Citation(s) in RCA: 228] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Targeted disruption of the murine retinaldehyde dehydrogenase 2 (Raldh2) gene precludes embryonic retinoic acid (RA) synthesis, leading to midgestational lethality (Niederreither, K., Subbarayan, V., Dolle, P. and Chambon, P. (1999). Nature Genet. 21, 444–448). We describe here the effects of this RA deficiency on the development of the hindbrain and associated neural crest. Morphological segmentation is impaired throughout the hindbrain of Raldh2−/− embryos, but its caudal portion becomes preferentially reduced in size during development. Specification of the midbrain region and of the rostralmost rhombomeres is apparently normal in the absence of RA synthesis. In contrast, marked alterations are seen throughout the caudal hindbrain of mutant embryos. Instead of being expressed in two alternate rhombomeres (r3 and r5), Krox20 is expressed in a single broad domain, correlating with an abnormal expansion of the r2-r3 marker Meis2. Instead of forming a defined r4, Hoxb1- and Wnt8A-expressing cells are scattered throughout the caudal hindbrain, whereas r5/r8 markers such as kreisler or group 3/4 Hox genes are undetectable or markedly downregulated. Lack of alternate Eph receptor gene expression could explain the failure to establish rhombomere boundaries. Increased apoptosis and altered migratory pathways of the posterior rhombencephalic neural crest cells are associated with impaired branchial arch morphogenesis in mutant embryos. We conclude that RA produced by the embryo is required to generate posterior cell fates in the developing mouse hindbrain, its absence leading to an abnormal r3 (and, to a lesser extent, r4) identity of the caudal hindbrain cells.
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Affiliation(s)
- K Niederreither
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP/Collège de France, CU de Strasbourg
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