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Tan AL, Christensen SE, Baker AK, Riley BB. Fgf, Hh, and pax2a differentially regulate expression of pax5 and pou3f3b in vestibular and auditory maculae in the zebrafish otic vesicle. Dev Dyn 2023; 252:1269-1279. [PMID: 37171017 DOI: 10.1002/dvdy.599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 04/02/2023] [Accepted: 04/30/2023] [Indexed: 05/13/2023] Open
Abstract
BACKGROUND The vertebrate inner ear contains distinct sensory epithelia specialized for auditory or vestibular function. In zebrafish, the first sensory epithelia form at opposite ends of the otic vesicle and are functionally distinct: the anterior utricular macula is essential for vestibular function whereas the posterior saccular macula is critical for hearing. Mechanisms distinguishing these maculae are not clear. Here, we examined the effects of manipulating Fgf or Hh on expression of pax5 and pou3f3b, unique markers of utricular and saccular identity. We also examined the roles of pax2a and atoh1a/b, early regulators of sensory specification. RESULTS fgf3 and fgf8a were uniquely required for pax5 and pou3f3b, respectively. Elevating Fgf or blocking Hh expanded expression of pax5 but repressed pou3f3b, while blocking Fgf had the opposite effect. Blocking sensory specification did not affect pax5 or pou3f3b, but both markers were lost in pax2a-/- mutants. Maintenance of pax2a expression requires Fgf, Hh and Pax2a itself. CONCLUSION Specification of utricular identity requires high Fgf and is repressed by Hh, whereas saccular identity requires Hh plus low Fgf. pax2a acts downstream of Fgf and Hh to maintain both fates. Comparison with mouse suggests this may reflect a broadly conserved developmental mechanism.
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Affiliation(s)
- Amy L Tan
- Biology Department, Texas A&M University, Texas, USA
| | | | | | - Bruce B Riley
- Biology Department, Texas A&M University, Texas, USA
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2
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Riley BB. Comparative assessment of Fgf's diverse roles in inner ear development: A zebrafish perspective. Dev Dyn 2021; 250:1524-1551. [PMID: 33830554 DOI: 10.1002/dvdy.343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 01/21/2023] Open
Abstract
Progress in understanding mechanisms of inner ear development has been remarkably rapid in recent years. The research community has benefited from the availability of several diverse model organisms, including zebrafish, chick, and mouse. The complexity of the inner ear has proven to be a challenge, and the complexity of the mammalian cochlea in particular has been the subject of intense scrutiny. Zebrafish lack a cochlea and exhibit a number of other differences from amniote species, hence they are sometimes seen as less relevant for inner ear studies. However, accumulating evidence shows that underlying cellular and molecular mechanisms are often highly conserved. As a case in point, consideration of the diverse functions of Fgf and its downstream effectors reveals many similarities between vertebrate species, allowing meaningful comparisons the can benefit the entire research community. In this review, I will discuss mechanisms by which Fgf controls key events in early otic development in zebrafish and provide direct comparisons with chick and mouse.
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Affiliation(s)
- Bruce B Riley
- Biology Department, Texas A&M University, College Station, Texas, USA
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3
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Warnecke A, Giesemann A. Embryology, Malformations, and Rare Diseases of the Cochlea. Laryngorhinootologie 2021; 100:S1-S43. [PMID: 34352899 PMCID: PMC8354575 DOI: 10.1055/a-1349-3824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Despite the low overall prevalence of individual rare diseases, cochlear
dysfunction leading to hearing loss represents a symptom in a large
proportion. The aim of this work was to provide a clear overview of rare
cochlear diseases, taking into account the embryonic development of the
cochlea and the systematic presentation of the different disorders. Although
rapid biotechnological and bioinformatic advances may facilitate the
diagnosis of a rare disease, an interdisciplinary exchange is often required
to raise the suspicion of a rare disease. It is important to recognize that
the phenotype of rare inner ear diseases can vary greatly not only in
non-syndromic but also in syndromic hearing disorders. Finally, it becomes
clear that the phenotype of the individual rare diseases cannot be
determined exclusively by classical genetics even in monogenetic
disorders.
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Affiliation(s)
- Athanasia Warnecke
- Klinik für Hals-, Nasen- und Ohrenheilkunde, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover.,Deutsche Forschungsgemeinschaft Exzellenzcluster"Hearing4all" - EXC 2177/1 - Project ID 390895286
| | - Anja Giesemann
- Institut für Neuroradiologie, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover
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4
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Yang LM, Ornitz DM. Sculpting the skull through neurosensory epithelial-mesenchymal signaling. Dev Dyn 2018; 248:88-97. [PMID: 30117627 DOI: 10.1002/dvdy.24664] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 12/16/2022] Open
Abstract
The vertebrate skull is a complex structure housing the brain and specialized sensory organs, including the eye, the inner ear, and the olfactory system. The close association between bones of the skull and the sensory organs they encase has posed interesting developmental questions about how the tissues scale with one another. Mechanisms that regulate morphogenesis of the skull are hypothesized to originate in part from the encased neurosensory organs. Conversely, the developing skull is hypothesized to regulate the growth of neurosensory organs, through mechanical forces or molecular signaling. Here, we review studies of epithelial-mesenchymal interactions during inner ear and olfactory system development that may coordinate the growth of the two sensory organs with their surrounding bone. We highlight recent progress in the field and provide evidence that mechanical forces arising from bone growth may affect olfactory epithelium development. Developmental Dynamics 248:88-97, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Lu M Yang
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri
| | - David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri
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5
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Ma JY, You D, Li WY, Lu XL, Sun S, Li HW. Bone morphogenetic proteins and inner ear development. J Zhejiang Univ Sci B 2018; 20:131-145. [PMID: 30112880 DOI: 10.1631/jzus.b1800084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bone morphogenetic proteins (BMPs) are the largest subfamily of the transforming growth factor-β superfamily, and they play important roles in the development of numerous organs, including the inner ear. The inner ear is a relatively small organ but has a highly complex structure and is involved in both hearing and balance. Here, we discuss BMPs and BMP signaling pathways and then focus on the role of BMP signal pathway regulation in the development of the inner ear and the implications this has for the treatment of human hearing loss and balance dysfunction.
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Affiliation(s)
- Jiao-Yao Ma
- Ear, Nose & Throat Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China
| | - Dan You
- Ear, Nose & Throat Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China
| | - Wen-Yan Li
- Ear, Nose & Throat Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China
| | - Xiao-Ling Lu
- Ear, Nose & Throat Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China
| | - Shan Sun
- Ear, Nose & Throat Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China
| | - Hua-Wei Li
- Ear, Nose & Throat Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China.,Institutes of Biomedical Sciences and the Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
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6
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Chang CN, Kioussi C. Location, Location, Location: Signals in Muscle Specification. J Dev Biol 2018; 6:E11. [PMID: 29783715 PMCID: PMC6027348 DOI: 10.3390/jdb6020011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/11/2018] [Accepted: 05/15/2018] [Indexed: 12/15/2022] Open
Abstract
Muscles control body movement and locomotion, posture and body position and soft tissue support. Mesoderm derived cells gives rise to 700 unique muscles in humans as a result of well-orchestrated signaling and transcriptional networks in specific time and space. Although the anatomical structure of skeletal muscles is similar, their functions and locations are specialized. This is the result of specific signaling as the embryo grows and cells migrate to form different structures and organs. As cells progress to their next state, they suppress current sequence specific transcription factors (SSTF) and construct new networks to establish new myogenic features. In this review, we provide an overview of signaling pathways and gene regulatory networks during formation of the craniofacial, cardiac, vascular, trunk, and limb skeletal muscles.
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Affiliation(s)
- Chih-Ning Chang
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA.
- Molecular Cell Biology Graduate Program, Oregon State University, Corvallis, OR 97331, USA.
| | - Chrissa Kioussi
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA.
- Molecular Cell Biology Graduate Program, Oregon State University, Corvallis, OR 97331, USA.
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7
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Ohta S, Wang B, Mansour SL, Schoenwolf GC. BMP regulates regional gene expression in the dorsal otocyst through canonical and non-canonical intracellular pathways. Development 2016; 143:2228-37. [PMID: 27151948 DOI: 10.1242/dev.137133] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/27/2016] [Indexed: 12/13/2022]
Abstract
The inner ear consists of two otocyst-derived, structurally and functionally distinct components: the dorsal vestibular and ventral auditory compartments. BMP signaling is required to form the vestibular compartment, but how it complements other required signaling molecules and acts intracellularly is unknown. Using spatially and temporally controlled delivery of signaling pathway regulators to developing chick otocysts, we show that BMP signaling regulates the expression of Dlx5 and Hmx3, both of which encode transcription factors essential for vestibular formation. However, although BMP regulates Dlx5 through the canonical SMAD pathway, surprisingly, it regulates Hmx3 through a non-canonical pathway involving both an increase in cAMP-dependent protein kinase A activity and the GLI3R to GLI3A ratio. Thus, both canonical and non-canonical BMP signaling establish the precise spatiotemporal expression of Dlx5 and Hmx3 during dorsal vestibular development. The identification of the non-canonical pathway suggests an intersection point between BMP and SHH signaling, which is required for ventral auditory development.
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Affiliation(s)
- Sho Ohta
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132-3401, USA
| | - Baolin Wang
- Department of Cell and Developmental Biology and Genetic Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Suzanne L Mansour
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132-3401, USA Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112-5330, USA
| | - Gary C Schoenwolf
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132-3401, USA
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8
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Brazil DP, Church RH, Surae S, Godson C, Martin F. BMP signalling: agony and antagony in the family. Trends Cell Biol 2015; 25:249-64. [DOI: 10.1016/j.tcb.2014.12.004] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 01/14/2023]
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9
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Chervenak AP, Hakim IS, Barald KF. Spatiotemporal expression of Zic genes during vertebrate inner ear development. Dev Dyn 2013; 242:897-908. [PMID: 23606270 DOI: 10.1002/dvdy.23978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/09/2013] [Accepted: 04/10/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Inner ear development involves signaling from surrounding tissues, including the adjacent hindbrain, periotic mesenchyme, and notochord. These signals include SHH, FGFs, BMPs, and WNTs from the hindbrain and SHH from the notochord. Zic genes, which are expressed in the dorsal neural tube and act during neural development, have been implicated as effectors of these pathways. This report examines whether Zic genes' involvement in inner ear development is a tenable hypothesis based on their expression patterns. RESULTS In the developing inner ear of both the chick and mouse, all of the Zic genes were expressed in the dorsal neural tube and variably in the periotic mesenchyme, but expression of the Zic genes in the otic epithelium was not found. The onset of expression differed among the Zic genes; within any given region surrounding the otic epithelium, multiple Zic genes were expressed in the same place at the same time. CONCLUSIONS Zic gene expression in the region of the developing inner ear is similar between mouse and chick. Zic expression domains overlap with sites of WNT and SHH signaling during otocyst patterning, suggesting a role for Zic genes in modulating signaling from these pathways.
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Affiliation(s)
- Andrew P Chervenak
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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10
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Abstract
The inner ear is a structurally complex vertebrate organ built to encode sound, motion, and orientation in space. Given its complexity, it is not surprising that inner ear dysfunction is a relatively common consequence of human genetic mutation. Studies in model organisms suggest that many genes currently known to be associated with human hearing impairment are active during embryogenesis. Hence, the study of inner ear development provides a rich context for understanding the functions of genes implicated in hearing loss. This chapter focuses on molecular mechanisms of inner ear development derived from studies of model organisms.
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Affiliation(s)
- Doris K Wu
- National Institute on Deafness and Other Communication Disorders, Rockville, Maryland 20850, USA.
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11
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Groves AK, Fekete DM. Shaping sound in space: the regulation of inner ear patterning. Development 2012; 139:245-57. [PMID: 22186725 DOI: 10.1242/dev.067074] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The inner ear is one of the most morphologically elaborate tissues in vertebrates, containing a group of mechanosensitive sensory organs that mediate hearing and balance. These organs are arranged precisely in space and contain intricately patterned sensory epithelia. Here, we review recent studies of inner ear development and patterning which reveal that multiple stages of ear development - ranging from its early induction from the embryonic ectoderm to the establishment of the three cardinal axes and the fine-grained arrangement of sensory cells - are orchestrated by gradients of signaling molecules.
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Affiliation(s)
- Andrew K Groves
- Departments of Neuroscience and Molecular and Human Genetics, BCM295, Baylor College of Medicine, Houston, TX 77030, USA.
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12
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Li Y, Laue K, Temtamy S, Aglan M, Kotan LD, Yigit G, Canan H, Pawlik B, Nürnberg G, Wakeling EL, Quarrell OW, Baessmann I, Lanktree MB, Yilmaz M, Hegele RA, Amr K, May KW, Nürnberg P, Topaloglu AK, Hammerschmidt M, Wollnik B. Temtamy preaxial brachydactyly syndrome is caused by loss-of-function mutations in chondroitin synthase 1, a potential target of BMP signaling. Am J Hum Genet 2010; 87:757-67. [PMID: 21129728 DOI: 10.1016/j.ajhg.2010.10.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 10/03/2010] [Accepted: 10/07/2010] [Indexed: 01/09/2023] Open
Abstract
Altered Bone Morphogenetic Protein (BMP) signaling leads to multiple developmental defects, including brachydactyly and deafness. Here we identify chondroitin synthase 1 (CHSY1) as a potential mediator of BMP effects. We show that loss of human CHSY1 function causes autosomal-recessive Temtamy preaxial brachydactyly syndrome (TPBS), mainly characterized by limb malformations, short stature, and hearing loss. After mapping the TPBS locus to chromosome 15q26-qterm, we identified causative mutations in five consanguineous TPBS families. In zebrafish, antisense-mediated chsy1 knockdown causes defects in multiple developmental processes, some of which are likely to also be causative in the etiology of TPBS. In the inner ears of zebrafish larvae, chsy1 is expressed similarly to the BMP inhibitor dan and in a complementary fashion to bmp2b. Furthermore, unrestricted Bmp2b signaling or loss of Dan activity leads to reduced chsy1 expression and, during epithelial morphogenesis, defects similar to those that occur upon Chsy1 inactivation, indicating that Bmp signaling affects inner-ear development by repressing chsy1. In addition, we obtained strikingly similar zebrafish phenotypes after chsy1 overexpression, which might explain why, in humans, brachydactyly can be caused by mutations leading either to loss or to gain of BMP signaling.
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Affiliation(s)
- Yun Li
- Center for Molecular Medicine Cologne, University of Cologne, Germany
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13
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BMP/SMAD signaling regulates the cell behaviors that drive the initial dorsal-specific regional morphogenesis of the otocyst. Dev Biol 2010; 347:369-81. [PMID: 20837004 DOI: 10.1016/j.ydbio.2010.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 09/02/2010] [Accepted: 09/02/2010] [Indexed: 12/20/2022]
Abstract
During development of the otocyst, regional morphogenesis establishes a dorsal vestibular chamber and a ventral auditory chamber, which collectively constitute the membranous labyrinth of the inner ear. We identified the earliest morphogenetic event heralding the formation of the vestibular chamber, a rapid thinning and expansion of the dorsolateral wall of the otocyst, and showed that this process is generated by changes in otocyst cell shape from columnar to squamous, as opposed to changes in other cell behaviors, such as localized changes in cell proliferation or cell death. Moreover, we showed that thinning and expansion of the dorsolateral otocyst is regulated by BMP/SMAD signaling, which is both sufficient and necessary for localized thinning and expansion. Finally, we showed that BMP/SMAD signaling causes fragmentation of E-cadherin in the dorsolateral otocyst, occurring concomitantly with cell shape change, suggesting that BMP/SMAD signaling regulates cell-cell adhesion during the initial morphogenesis of the otocyst epithelium. Collectively, our results show that BMP signaling via SMADs regulates the cell behaviors that drive the initial dorsal-specific morphogenesis of the otocyst, providing new information about how regional morphogenesis of a complex organ rudiment, the developing membranous labyrinth, is initiated.
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14
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Hwang CH, Guo D, Harris MA, Howard O, Mishina Y, Gan L, Harris SE, Wu DK. Role of bone morphogenetic proteins on cochlear hair cell formation: analyses of Noggin and Bmp2 mutant mice. Dev Dyn 2010; 239:505-13. [PMID: 20063299 DOI: 10.1002/dvdy.22200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The mammalian organ of Corti of the inner ear is a highly sophisticated sensory end organ responsible for detecting sound. Noggin is a secreted glycoprotein, which antagonizes bone morphogenetic proteins 2 and 4 (Bmp2 and Bmp4). The lack of this antagonist causes increased rows of inner and outer hair cells in the organ of Corti. In mice, Bmp2 is expressed transiently in nascent cochlear hair cells. To investigate whether Noggin normally modulates the levels of Bmp2 for hair cell formation, we deleted Bmp2 in the cochlear hair cells using two cre strains, Foxg1(cre/+) and Gfi1(cre/+). Bmp2 conditional knockout cochleae generated using these two cre strains show normal hair cells. Furthermore, Gfi1(cre/+);Bmp2(lox/-) mice are viable and have largely normal hearing. The combined results of Noggin and Bmp2 mutants suggest that Noggin is likely to regulate other Bmps in the cochlea such as Bmp4.
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Affiliation(s)
- Chan Ho Hwang
- Laboratory of Molecular Biology, National Institute on Deafness and Other Communication Disorders, Rockville, Maryland, USA
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15
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16
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Liang JK, Bok J, Wu DK. Distinct contributions from the hindbrain and mesenchyme to inner ear morphogenesis. Dev Biol 2009; 337:324-34. [PMID: 19896934 DOI: 10.1016/j.ydbio.2009.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 10/29/2009] [Accepted: 11/02/2009] [Indexed: 10/20/2022]
Abstract
A mature inner ear is a complex structure consisting of vestibular and auditory components. Microsurgical ablations, rotations, and translocations were performed in ovo to identify the tissues that control inner ear morphogenesis. We show that mesenchyme/ectoderm adjacent to the developing ear specifically governs the shape of vestibular components - the semicircular canals and ampullae - by conferring anteroposterior axial information to these structures. In contrast, removal of individual hindbrain rhombomeres adjacent to the developing ear preferentially affects the growth and morphogenesis of the auditory subdivision, the cochlear duct, or basilar papilla. Removal of rhombomere 5 affects cochlear duct growth, while rhombomere 6 removal affects cochlear growth and morphogenesis. Rotating rhombomeres 5 and 6 along the anteroposterior axis also impacts cochlear duct morphogenesis but has little effect on the vestibular components. Our studies indicate that discrete tissues, acting at a distance, control the morphogenesis of distinct elements of the inner ear. These results provide a basis for identifying factors that are essential to vestibular and auditory development in vertebrates.
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Affiliation(s)
- Jennifer K Liang
- National Institute on Deafness and Other Communication Disorders, 5 Research Court, Rockville, MD 20850, USA
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17
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Hwang CH, Simeone A, Lai E, Wu DK. Foxg1is required for proper separation and formation of sensory cristae during inner ear development. Dev Dyn 2009; 238:2725-34. [PMID: 19842177 DOI: 10.1002/dvdy.22111] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Chan Ho Hwang
- Lab of Molecular Biology, National Institute on Deafness and Other Communication Disorders, Rockville, Maryland 20850, USA
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18
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Soukup GA, Fritzsch B, Pierce ML, Weston MD, Jahan I, McManus MT, Harfe BD. Residual microRNA expression dictates the extent of inner ear development in conditional Dicer knockout mice. Dev Biol 2009; 328:328-41. [PMID: 19389351 PMCID: PMC2793102 DOI: 10.1016/j.ydbio.2009.01.037] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 01/25/2009] [Accepted: 01/27/2009] [Indexed: 01/09/2023]
Abstract
Inner ear development requires coordinated transformation of a uniform sheet of cells into a labyrinth with multiple cell types. While numerous regulatory proteins have been shown to play critical roles in this process, the regulatory functions of microRNAs (miRNAs) have not been explored. To demonstrate the importance of miRNAs in inner ear development, we generated conditional Dicer knockout mice by the expression of Cre recombinase in the otic placode at E8.5. Otocyst-derived ganglia exhibit rapid neuron-specific miR-124 depletion by E11.5, degeneration by E12.5, and profound defects in subsequent sensory epithelial innervations by E17.5. However, the small and malformed inner ear at E17.5 exhibits residual and graded hair cell-specific miR-183 expression in the three remaining sensory epithelia (posterior crista, utricle, and cochlea) that closely corresponds to the degree of hair cell and sensory epithelium differentiation, and Fgf10 expression required for morphohistogenesis. The highest miR-183 expression is observed in near-normal hair cells of the posterior crista, whereas the reduced utricular macula demonstrates weak miR-183 expression and develops presumptive hair cells with numerous disorganized microvilli instead of ordered stereocilia. The correlation of differential and delayed depletion of mature miRNAs with the derailment of inner ear development demonstrates that miRNAs are crucial for inner ear neurosensory development and neurosensory-dependent morphogenesis.
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Affiliation(s)
- Garrett A Soukup
- Department of Biomedical Sciences, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA.
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19
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Colantonio JR, Vermot J, Wu D, Langenbacher AD, Fraser S, Chen JN, Hill KL. The dynein regulatory complex is required for ciliary motility and otolith biogenesis in the inner ear. Nature 2008; 457:205-9. [PMID: 19043402 DOI: 10.1038/nature07520] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 09/30/2008] [Indexed: 11/09/2022]
Abstract
In teleosts, proper balance and hearing depend on mechanical sensors in the inner ear. These sensors include actin-based microvilli and microtubule-based cilia that extend from the surface of sensory hair cells and attach to biomineralized 'ear stones' (or otoliths). Otolith number, size and placement are under strict developmental control, but the mechanisms that ensure otolith assembly atop specific cells of the sensory epithelium are unclear. Here we demonstrate that cilia motility is required for normal otolith assembly and localization. Using in vivo video microscopy, we show that motile tether cilia at opposite poles of the otic vesicle create fluid vortices that attract otolith precursor particles, thereby biasing an otherwise random distribution to direct localized otolith seeding on tether cilia. Independent knockdown of subunits for the dynein regulatory complex and outer-arm dynein disrupt cilia motility, leading to defective otolith biogenesis. These results demonstrate a requirement for the dynein regulatory complex in vertebrates and show that cilia-driven flow is a key epigenetic factor in controlling otolith biomineralization.
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Affiliation(s)
- Jessica R Colantonio
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095, USA
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