1
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Mori Y, Smith S, Wang J, Munjal A. Versican controlled by Lmx1b regulates hyaluronate density and hydration for semicircular canal morphogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592968. [PMID: 38766227 PMCID: PMC11100707 DOI: 10.1101/2024.05.07.592968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
During inner ear semicircular canal morphogenesis in zebrafish, patterned canal-genesis zones express genes for extracellular matrix component synthesis. These include hyaluronan and the hyaluronan-binding chondroitin sulfate proteoglycan Versican, which are abundant in the matrices of many developing organs. Charged hyaluronate polymers play a key role in canal morphogenesis through osmotic swelling. However, the developmental factor(s) that control the synthesis of the matrix components and regulation of hyaluronate density and swelling are unknown. Here, we identify the transcription factor, Lmx1b, as a positive transcriptional regulator of hyaluronan, Versican, and chondroitin synthesis genes crucial for canal morphogenesis. We show that Versican regulates hyaluronan density through its protein core, whereas the charged chondroitin side chains contribute to the osmotic swelling of hyaluronate. Versican-tuned properties of hyaluronate matrices may be a broadly used mechanism in morphogenesis with important implications for understanding diseases where these matrices are impaired, and for hydrogel engineering for tissue regeneration.
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Affiliation(s)
- Yusuke Mori
- Department of Cell Biology, Duke University School of Medicine, Durham NC 27710
| | - Sierra Smith
- Department of Cell Biology, Duke University School of Medicine, Durham NC 27710
| | - Jiacheng Wang
- Department of Cell Biology, Duke University School of Medicine, Durham NC 27710
| | - Akankshi Munjal
- Department of Cell Biology, Duke University School of Medicine, Durham NC 27710
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2
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Functional Characterization of the MYO6 Variant p.E60Q in Non-Syndromic Hearing Loss Patients. Int J Mol Sci 2022; 23:ijms23063369. [PMID: 35328790 PMCID: PMC8949016 DOI: 10.3390/ijms23063369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/04/2022] [Accepted: 03/10/2022] [Indexed: 11/24/2022] Open
Abstract
Hereditary hearing loss (HHL) is a common genetic disorder accounting for at least 60% of pre-lingual deafness in children, of which 70% is inherited in an autosomal recessive pattern. The long tradition of consanguinity among the Qatari population has increased the prevalence of HHL, which negatively impacts the quality of life. Here, we functionally validated the pathogenicity of the c.178G>C, p.E60Q mutation in the MYO6 gene, which was detected previously in a Qatari HHL family, using cellular and animal models. In vitro analysis was conducted in HeLa cells transiently transfected with plasmids carrying MYO6WT or MYO6p.E60Q, and a zebrafish model was generated to characterize the in vivo phenotype. Cells transfected with MYO6WT showed higher expression of MYO6 in the plasma membrane and increased ATPase activity. Modeling the human MYO6 variants in zebrafish resulted in severe otic defects. At 72 h post-injection, MYO6p.E60Q embryos demonstrated alterations in the sizes of the saccule and utricle. Additionally, zebrafish with MYO6p.E60Q displayed super-coiled and bent hair bundles in otic hair cells when compared to control and MYO6WT embryos. In conclusion, our cellular and animal models add support to the in silico prediction that the p.E60Q missense variant is pathogenic and damaging to the protein. Since the c.178G>C MYO6 variant has a 0.5% allele frequency in the Qatari population, about 400 times higher than in other populations, it could contribute to explaining the high prevalence of hearing impairment in Qatar.
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3
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Vona B, Doll J, Hofrichter MAH, Haaf T, Varshney GK. Small fish, big prospects: using zebrafish to unravel the mechanisms of hereditary hearing loss. Hear Res 2020; 397:107906. [PMID: 32063424 PMCID: PMC7415493 DOI: 10.1016/j.heares.2020.107906] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/13/2020] [Accepted: 01/29/2020] [Indexed: 12/16/2022]
Abstract
Over the past decade, advancements in high-throughput sequencing have greatly enhanced our knowledge of the mutational signatures responsible for hereditary hearing loss. In its present state, the field has a largely uncensored view of protein coding changes in a growing number of genes that have been associated with hereditary hearing loss, and many more that have been proposed as candidate genes. Sequencing data can now be generated using methods that have become widespread and affordable. The greatest hurdles facing the field concern functional validation of uncharacterized genes and rapid application to human diseases, including hearing and balance disorders. To date, over 30 hearing-related disease models exist in zebrafish. New genome editing technologies, including CRISPR/Cas9 will accelerate the functional validation of hearing loss genes and variants in zebrafish. Here, we discuss current progress in the field and recent advances in genome editing approaches.
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Affiliation(s)
- Barbara Vona
- Department of Otolaryngology--Head & Neck Surgery, Tübingen Hearing Research Centre, Eberhard Karls University Tübingen, Tübingen, Germany.
| | - Julia Doll
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | | | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States.
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4
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Wang F, Ren D, Liang X, Ke S, Zhang B, Hu B, Song X, Wang X. A long noncoding RNA cluster-based genomic locus maintains proper development and visual function. Nucleic Acids Res 2020; 47:6315-6329. [PMID: 31127312 PMCID: PMC6614851 DOI: 10.1093/nar/gkz444] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 04/29/2019] [Accepted: 05/10/2019] [Indexed: 01/07/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) represent a group of regulatory RNAs that play critical roles in numerous cellular events, but their functional importance in development remains largely unexplored. Here, we discovered a series of previously unidentified gene clusters harboring conserved lncRNAs at the nonimprinting regions in brain (CNIBs). Among the seven identified CNIBs, human CNIB1 locus is located at Chr 9q33.3 and conserved from Danio rerio to Homo sapiens. Chr 9q33.3-9q34.11 microdeletion has previously been linked to human nail-patella syndrome (NPS) which is frequently accompanied by developmental and visual deficiencies. By generating CNIB1 deletion alleles in zebrafish, we demonstrated the requirement of CNIB1 for proper growth and development, and visual activities. Furthermore, we found that the role of CNIB1 on visual activity is mediated through a regulator of ocular development-lmx1bb. Collectively, our study shows that CNIB1 lncRNAs are important for zebrafish development and provides an lncRNA cluster-mediated pathophysiological mechanism for human Chr 9q33.3-9q34.11 microdeletion syndrome.
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Affiliation(s)
- Fei Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Dalong Ren
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaolin Liang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shengwei Ke
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bowen Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bing Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaoyuan Song
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiangting Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
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5
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Lee MS, Philippe J, Katsanis N, Zhou W. Polyketide Synthase Plays a Conserved Role in Otolith Formation. Zebrafish 2019; 16:363-369. [PMID: 31188077 DOI: 10.1089/zeb.2019.1734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Otoliths (ear stones) are biomineralized complexes essential for the balancing and hearing function of the inner ears in fish. Their formation is controlled by a genetically programmed biological process that is yet to be defined. We have isolated and characterized a spontaneous genetic mutant zebrafish with a complete absence of otoliths, named no otolith 1 (not1). not1 mutants are unable to develop otoliths during embryonic stages and fail to respond to acoustic stimuli, indicating an inner ear defect. We identified a deleterious mutation (G239R) that altered a highly conserved amino acid residue in the zebrafish ortholog of type I polyketide synthase (pks1) to underlie these phenotypes and showed that expression of the polyketide synthase gene of Japanese medaka fish could rescue the otolith deficiency in not1 mutant zebrafish. Our finding highlights a critical and conserved role of type I polyketide synthase in the initiation of otolith formation. Given the functional homology between otoliths in teleost fish and otoconia in mammals and humans, not1 mutants provide a new animal model for the study of human otoconia-related diseases.
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Affiliation(s)
- Mi-Sun Lee
- 1Department of Biological Chemistry, Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan
| | - Julien Philippe
- 2Center for Human Disease Modeling, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina.,3Department of Cell Biology, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina
| | - Nicholas Katsanis
- 2Center for Human Disease Modeling, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina.,3Department of Cell Biology, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina
| | - Weibin Zhou
- 2Center for Human Disease Modeling, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina.,4Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina
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6
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Thiessen KD, Grzegorski SJ, Chin Y, Higuchi LN, Wilkinson CJ, Shavit JA, Kramer KL. Zebrafish otolith biomineralization requires polyketide synthase. Mech Dev 2019; 157:1-9. [PMID: 30974150 PMCID: PMC6531356 DOI: 10.1016/j.mod.2019.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/12/2019] [Accepted: 04/01/2019] [Indexed: 11/20/2022]
Abstract
Deflecting biomineralized crystals attached to vestibular hair cells are necessary for maintaining balance. Zebrafish (Danio rerio) are useful organisms to study these biomineralized crystals called otoliths, as many required genes are homologous to human otoconial development. We sought to identify and characterize the causative gene in a trio of homozygous recessive mutants, no content (nco) and corkscrew (csr), and vanished (vns), which fail to develop otoliths during early ear development. We show that nco, csr, and vns have potentially deleterious mutations in polyketide synthase (pks1), a multi-modular protein that has been previously implicated in biomineralization events in chordates and echinoderms. We found that Otoconin-90 (Oc90) expression within the otocyst is diffuse in nco and csr; therefore, it is not sufficient for otolith biomineralization in zebrafish. Similarly, normal localization of Otogelin, a protein required for otolith tethering in the otolithic membrane, is not sufficient for Oc90 attachment. Furthermore, eNOS signaling and Endothelin-1 signaling were the most up- and down-regulated pathways during otolith agenesis in nco, respectively. Our results demonstrate distinct processes for otolith nucleation and biomineralization in vertebrates and will be a starting point for models that are independent of Oc90-mediated seeding. This study will serve as a basis for investigating the role of eNOS signaling and Endothelin-1 signaling during otolith formation.
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Affiliation(s)
- Kevin D Thiessen
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - Steven J Grzegorski
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
| | - Yvonne Chin
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, United Kingdom
| | - Lisa N Higuchi
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States
| | - Christopher J Wilkinson
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, United Kingdom
| | - Jordan A Shavit
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
| | - Kenneth L Kramer
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, United States.
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7
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DeSmidt AA, Zou B, Grati M, Yan D, Mittal R, Yao Q, Richmond MT, Denyer S, Liu XZ, Lu Z. Zebrafish Model for Nonsyndromic X-Linked Sensorineural Deafness, DFNX1. Anat Rec (Hoboken) 2019; 303:544-555. [PMID: 30874365 DOI: 10.1002/ar.24115] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/23/2018] [Accepted: 09/05/2018] [Indexed: 11/08/2022]
Abstract
Hereditary deafness is often a neurosensory disorder and affects the quality of life of humans. Only three X-linked genes (POU class 3 homeobox 4 (POU3F4), phosphoribosyl pyrophosphate synthetase 1 (PRPS1), and small muscle protein X-linked (SMPX)) are known to be involved in nonsyndromic hearing loss. Four PRPS1 missense mutations have been found to associate with X-linked nonsyndromic sensorineural deafness (DFNX1/DFN2) in humans. However, a causative relationship between PRPS1 mutations and hearing loss in humans has not been well studied in any animal model. Phosphoribosyl pyrophosphate synthetase 1 (PRS-I) is highly conserved in vertebrate taxa. In this study, we used the zebrafish as a model to investigate the auditory role of zebrafish orthologs (prps1a and prps1b) of the human PRPS1 gene with whole mount in situ hybridization, reverse transcription polymerase chain reaction, phenotypic screening, confocal imaging, and electrophysiological methods. We found that both prps1a and prps1b genes were expressed in the inner ear of zebrafish. Splice-blocking antisense morpholino oligonucleotides (MO1 and MO2) caused exon-2 skip and intron-2 retention of prps1a and exon-2 skip and intron-1 retention of prps1b to knock down functions of the genes, respectively. MO1 and MO2 morphants had smaller otic vesicles and otoliths, fewer inner ear hair cells, and lower microphonic response amplitude and sensitivity than control zebrafish. Therefore, knockdown of either prps1a or prps1b resulted in significant sensorineural hearing loss in zebrafish. We conclude that the prps1 genes are essential for hearing in zebrafish, which has the potential to help us understand the biology of human deafness DFNX1/DFN2. Anat Rec, 303:544-555, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
| | - Bing Zou
- Department of Biology, University of Miami, Coral Gables, Florida.,Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - M'hamed Grati
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Qi Yao
- Department of Biology, University of Miami, Coral Gables, Florida.,Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | | | - Steven Denyer
- Department of Biology, University of Miami, Coral Gables, Florida
| | - Xue Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida.,Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Zhongmin Lu
- Department of Biology, University of Miami, Coral Gables, Florida.,Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida.,Neuroscience Program, University of Miami, Miami, Florida.,International Center for Marine Studies, Shanghai Ocean University, Shanghai, People's Republic of China
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8
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Girotto G, Morgan A, Krishnamoorthy N, Cocca M, Brumat M, Bassani S, La Bianca M, Di Stazio M, Gasparini P. Next Generation Sequencing and Animal Models Reveal SLC9A3R1 as a New Gene Involved in Human Age-Related Hearing Loss. Front Genet 2019; 10:142. [PMID: 30863428 PMCID: PMC6399162 DOI: 10.3389/fgene.2019.00142] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/11/2019] [Indexed: 01/29/2023] Open
Abstract
Age-related hearing loss (ARHL) is the most common sensory impairment in the elderly affecting millions of people worldwide. To shed light on the genetics of ARHL, a large cohort of 464 Italian patients has been deeply characterized at clinical and molecular level. In particular, 46 candidate genes, selected on the basis of genome-wide association studies (GWAS), animal models and literature updates, were analyzed by targeted re-sequencing. After filtering and prioritization steps, SLC9A3R1 has been identified as a strong candidate and then validated by "in vitro" and "in vivo" studies. Briefly, a rare (MAF: 2.886e-5) missense variant c.539G > A, p.(R180Q) was detected in two unrelated male patients affected by ARHL characterized by a severe to profound high-frequency hearing loss. The variant, predicted as damaging, was not present in healthy matched controls. Protein modeling confirmed the pathogenic effect of p.(R180Q) variant on protein's structure leading to a change in the total number of hydrogen bonds. In situ hybridization showed slc9a3r1 expression in zebrafish inner ear. A zebrafish knock-in model, generated by CRISPR-Cas9 technology, revealed a reduced auditory response at all frequencies in slc9a3r1 R180Q/R180Q mutants compared to slc9a3r1 +/+ and slc9a3r1 +/R180Q animals. Moreover, a significant reduction (5.8%) in the total volume of the saccular otolith (which is responsible for sound detection) was observed in slc9a3r1 R180Q/R180Q compared to slc9a3r1 +/+ (P = 0.0014), while the utricular otolith, necessary for balance, was not affected in agreement with the human phenotype. Overall, these data strongly support the role of SLC9A3R1 gene in the pathogenesis of ARHL opening new perspectives in terms of diagnosis, prevention and treatment.
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Affiliation(s)
- Giorgia Girotto
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Anna Morgan
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Navaneethakrishnan Krishnamoorthy
- Sidra Medical and Research Center, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Massimiliano Cocca
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Marco Brumat
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Sissy Bassani
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Martina La Bianca
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Mariateresa Di Stazio
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Paolo Gasparini
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
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9
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Swinburne IA, Mosaliganti KR, Upadhyayula S, Liu TL, Hildebrand DGC, Tsai TYC, Chen A, Al-Obeidi E, Fass AK, Malhotra S, Engert F, Lichtman JW, Kirchhausen T, Betzig E, Megason SG. Lamellar projections in the endolymphatic sac act as a relief valve to regulate inner ear pressure. eLife 2018; 7:37131. [PMID: 29916365 PMCID: PMC6008045 DOI: 10.7554/elife.37131] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 05/09/2018] [Indexed: 01/23/2023] Open
Abstract
The inner ear is a fluid-filled closed-epithelial structure whose function requires maintenance of an internal hydrostatic pressure and fluid composition. The endolymphatic sac (ES) is a dead-end epithelial tube connected to the inner ear whose function is unclear. ES defects can cause distended ear tissue, a pathology often seen in hearing and balance disorders. Using live imaging of zebrafish larvae, we reveal that the ES undergoes cycles of slow pressure-driven inflation followed by rapid deflation. Absence of these cycles in lmx1bb mutants leads to distended ear tissue. Using serial-section electron microscopy and adaptive optics lattice light-sheet microscopy, we find a pressure relief valve in the ES comprised of partially separated apical junctions and dynamic overlapping basal lamellae that separate under pressure to release fluid. We propose that this lmx1-dependent pressure relief valve is required to maintain fluid homeostasis in the inner ear and other fluid-filled cavities. The most internal part of the human ear, the inner ear, is essential for us to hear and have a sense of balance. It is formed by a complex series of connected cavities filled by a liquid. When sound waves and changes in the position of the body make this liquid move, specialized ‘hair’ cells can detect these subtle movements; neurons then relay this information to the brain where it is decoded and interpreted. For the inner ear to work properly, the body needs to finely regulate the pressure created by the liquid inside the cavities. For example, people with unstable pressure in their ears can experience deafness or problems with balance. A structure known as the endolymphatic sac, which is a balloon-like chamber connected to the rest of the inner ear by a thin tube, helps with this regulation. However, scientists are still unsure about how exactly the sac performs its role. One problem is that the inner ear is difficult to study because it is encased in one of the densest bones in the body. Many other animals also have inner ears, from fish to birds and mammals. Here, Swinburne et al. examine the inner ear of zebrafish embryos because, in this fish, the ear starts working before the bones around it form; the structure is therefore accessible for injections and microscopy. Experiments show that when the pressure in the inner ear rises, the endolymphatic sac slowly fills up with the ear liquid, and then it rapidly deflates. Fish with mutations that stop the sac from deflating have overinflated sacs, which is a symptom also found in certain patients with hearing and balance disorders. Looking into the details of these inflation-deflation cycles, Swinburne et al. found that the cells that form the sac have gaps between them, unlike a normal sheet of cells. A flap covers these gaps to keep the liquid in, but under pressure, the flap opens and the liquid can escape. These results show that the endolymphatic sac works as a pressure relief valve for the inner ear. Ultimately, understanding how pressure is regulated in the ear could help patients with inner ear disorders. It could also serve as a template to investigate how eyes, kidneys and the brain, which all have liquid-filled cavities, control their internal pressure.
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Affiliation(s)
- Ian A Swinburne
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | | | - Srigokul Upadhyayula
- Department of Pediatrics, Harvard Medical School, Boston, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, United States.,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Tsung-Li Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - David G C Hildebrand
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Tony Y-C Tsai
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Anzhi Chen
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Ebaa Al-Obeidi
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Anna K Fass
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Samir Malhotra
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Florian Engert
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Jeff W Lichtman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Tomas Kirchhausen
- Department of Pediatrics, Harvard Medical School, Boston, United States.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Eric Betzig
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Sean G Megason
- Department of Systems Biology, Harvard Medical School, Boston, United States
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10
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Behavioral methods for the functional assessment of hair cells in zebrafish. Front Med 2017; 11:178-190. [PMID: 28349300 DOI: 10.1007/s11684-017-0507-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 11/24/2016] [Indexed: 10/19/2022]
Abstract
Zebrafish is an emerging animal model for studies on auditory system. This model presents high comparability with humans, good accessibility to the hearing organ, and high throughput capacity. To better utilize this animal model, methodologies need to be used to quantify the hearing function of the zebrafish. Zebrafish displays a series of innate and robust behavior related to its auditory function. Here, we reviewed the advantage of using zebrafish in auditory research and then introduced three behavioral tests, as follows: the startle response, the vestibular-ocular reflex, and rheotaxis. These tests are discussed in terms of their physiological characteristics, up-to-date technical development, and apparatus description. Test limitation and areas to improve are also introduced. Finally, we revealed the feasibility of these applications in zebrafish behavioral assessment and their potential in the high-throughput screening on hearing-related genes and drugs.
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11
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Hilinski WC, Bostrom JR, England SJ, Juárez-Morales JL, de Jager S, Armant O, Legradi J, Strähle U, Link BA, Lewis KE. Lmx1b is required for the glutamatergic fates of a subset of spinal cord neurons. Neural Dev 2016; 11:16. [PMID: 27553035 PMCID: PMC4995821 DOI: 10.1186/s13064-016-0070-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/08/2016] [Indexed: 01/27/2023] Open
Abstract
Background Alterations in neurotransmitter phenotypes of specific neurons can cause imbalances in excitation and inhibition in the central nervous system (CNS), leading to diseases. Therefore, the correct specification and maintenance of neurotransmitter phenotypes is vital. As with other neuronal properties, neurotransmitter phenotypes are often specified and maintained by particular transcription factors. However, the specific molecular mechanisms and transcription factors that regulate neurotransmitter phenotypes remain largely unknown. Methods In this paper we use single mutant, double mutant and transgenic zebrafish embryos to elucidate the functions of Lmx1ba and Lmx1bb in the regulation of spinal cord interneuron neurotransmitter phenotypes. Results We demonstrate that lmx1ba and lmx1bb are both expressed in zebrafish spinal cord and that lmx1bb is expressed by both V0v cells and dI5 cells. Our functional analyses demonstrate that these transcription factors are not required for neurotransmitter fate specification at early stages of development, but that in embryos with at least two lmx1ba and/or lmx1bb mutant alleles there is a reduced number of excitatory (glutamatergic) spinal interneurons at later stages of development. In contrast, there is no change in the numbers of V0v or dI5 cells. These data suggest that lmx1b-expressing spinal neurons still form normally, but at least a subset of them lose, or do not form, their normal excitatory fates. As the reduction in glutamatergic cells is only seen at later stages of development, Lmx1b is probably required either for the maintenance of glutamatergic fates or to specify glutamatergic phenotypes of a subset of later forming neurons. Using double labeling experiments, we also show that at least some of the cells that lose their normal glutamatergic phenotype are V0v cells. Finally, we also establish that Evx1 and Evx2, two transcription factors that are required for V0v cells to acquire their excitatory neurotransmitter phenotype, are also required for lmx1ba and lmx1bb expression in these cells, suggesting that Lmx1ba and Lmx1bb act downstream of Evx1 and Evx2 in V0v cells. Conclusions Lmx1ba and Lmx1bb function at least partially redundantly in the spinal cord and three functional lmx1b alleles are required in zebrafish for correct numbers of excitatory spinal interneurons at later developmental stages. Taken together, our data significantly enhance our understanding of how spinal cord neurotransmitter fates are regulated.
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Affiliation(s)
- William C Hilinski
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.,Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Avenue, Syracuse, NY, 13210, USA
| | - Jonathan R Bostrom
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Samantha J England
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Sarah de Jager
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Olivier Armant
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021, Karlsruhe, Germany
| | - Jessica Legradi
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021, Karlsruhe, Germany
| | - Uwe Strähle
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021, Karlsruhe, Germany
| | - Brian A Link
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.
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12
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Leventea E, Hazime K, Zhao C, Malicki J. Analysis of cilia structure and function in zebrafish. Methods Cell Biol 2016; 133:179-227. [PMID: 27263414 DOI: 10.1016/bs.mcb.2016.04.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cilia are microtubule-based protrusions on the surface of most eukaryotic cells. They are found in most, if not all, vertebrate organs. Prominent cilia form in sensory structures, the eye, the ear, and the nose, where they are crucial for the detection of environmental stimuli, such as light and odors. Cilia are also involved in developmental processes, including left-right asymmetry formation, limb morphogenesis, and the patterning of neurons in the neural tube. Some cilia, such as those found in nephric ducts, are thought to have mechanosensory roles. Zebrafish proved very useful in genetic analysis and imaging of cilia-related processes, and in the modeling of mechanisms behind human cilia abnormalities, known as ciliopathies. A number of zebrafish defects resemble those seen in human ciliopathies. Forward and reverse genetic strategies generated a wide range of cilia mutants in zebrafish, which can be studied using sophisticated genetic and imaging approaches. In this chapter, we provide a set of protocols to examine cilia morphology, motility, and cilia-related defects in a variety of organs, focusing on the embryo and early postembryonic development.
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Affiliation(s)
- E Leventea
- The University of Sheffield, Sheffield, United Kingdom
| | - K Hazime
- The University of Sheffield, Sheffield, United Kingdom
| | - C Zhao
- The University of Sheffield, Sheffield, United Kingdom; Ocean University of China, Qingdao, China
| | - J Malicki
- The University of Sheffield, Sheffield, United Kingdom
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13
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Schulz-Mirbach T, Ladich F. Diversity of Inner Ears in Fishes: Possible Contribution Towards Hearing Improvements and Evolutionary Considerations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 877:341-91. [DOI: 10.1007/978-3-319-21059-9_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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14
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Manda P, Balhoff JP, Lapp H, Mabee P, Vision TJ. Using the phenoscape knowledgebase to relate genetic perturbations to phenotypic evolution. Genesis 2015. [PMID: 26220875 DOI: 10.1002/dvg.22878] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The abundance of phenotypic diversity among species can enrich our knowledge of development and genetics beyond the limits of variation that can be observed in model organisms. The Phenoscape Knowledgebase (KB) is designed to enable exploration and discovery of phenotypic variation among species. Because phenotypes in the KB are annotated using standard ontologies, evolutionary phenotypes can be compared with phenotypes from genetic perturbations in model organisms. To illustrate the power of this approach, we review the use of the KB to find taxa showing evolutionary variation similar to that of a query gene. Matches are made between the full set of phenotypes described for a gene and an evolutionary profile, the latter of which is defined as the set of phenotypes that are variable among the daughters of any node on the taxonomic tree. Phenoscape's semantic similarity interface allows the user to assess the statistical significance of each match and flags matches that may only result from differences in annotation coverage between genetic and evolutionary studies. Tools such as this will help meet the challenge of relating the growing volume of genetic knowledge in model organisms to the diversity of phenotypes in nature. The Phenoscape KB is available at http://kb.phenoscape.org.
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Affiliation(s)
- Prashanti Manda
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina.,US National Evolutionary Synthesis Center, Durham, North Carolina
| | - James P Balhoff
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina.,US National Evolutionary Synthesis Center, Durham, North Carolina
| | - Hilmar Lapp
- US National Evolutionary Synthesis Center, Durham, North Carolina.,Center for Genomic and Computational Biology, Duke University, Durham, North Carolina
| | - Paula Mabee
- Department of Biology, University of South Dakota, Vermillion, South Dakota
| | - Todd J Vision
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina.,US National Evolutionary Synthesis Center, Durham, North Carolina
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15
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Monroe JD, Rajadinakaran G, Smith ME. Sensory hair cell death and regeneration in fishes. Front Cell Neurosci 2015; 9:131. [PMID: 25954154 PMCID: PMC4404912 DOI: 10.3389/fncel.2015.00131] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 03/21/2015] [Indexed: 01/31/2023] Open
Abstract
Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation vs. direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.
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Affiliation(s)
- Jerry D Monroe
- Department of Biology, Western Kentucky University Bowling Green, KY, USA
| | - Gopinath Rajadinakaran
- Department of Genetics and Genome Sciences, University of Connecticut Health Center Farmington, CT, USA
| | - Michael E Smith
- Department of Biology, Western Kentucky University Bowling Green, KY, USA
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16
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Hojo M, Omi A, Hamanaka G, Shindo K, Shimada A, Kondo M, Narita T, Kiyomoto M, Katsuyama Y, Ohnishi Y, Irie N, Takeda H. Unexpected link between polyketide synthase and calcium carbonate biomineralization. ZOOLOGICAL LETTERS 2015; 1:3. [PMID: 26605048 PMCID: PMC4604110 DOI: 10.1186/s40851-014-0001-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 10/15/2014] [Indexed: 06/05/2023]
Abstract
INTRODUCTION Calcium carbonate biominerals participate in diverse physiological functions. Despite intensive studies, little is known about how mineralization is initiated in organisms. RESULTS We analyzed the medaka spontaneous mutant, ha, defective in otolith (calcareous ear stone) formation. ha lacks a trigger for otolith mineralization, and the causative gene was found to encode polyketide synthase (pks), a multifunctional enzyme mainly found in bacteria, fungi, and plant. Subsequent experiments demonstrate that the products of medaka PKS, most likely polyketides or their derivatives, act as nucleation facilitators in otolith mineralization. The generality of this novel PKS function is supported by the essential role of echinoderm PKS in calcareous skeleton formation together with the presence of PKSs in a much wider range of animals from coral to vertebrates. CONCLUSION The present study first links PKS to biomineralization and provides a genetic cue for biogeochemistry of carbon and calcium cycles.
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Affiliation(s)
- Motoki Hojo
- />Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
- />Present address: Department of Pharmaceutical and Environmental Sciences, Tokyo Metropolitan Institute of Public Health, 3-24–1, Hyakunincho, Shinju-ku, Tokyo 169-0073 Japan
| | - Ai Omi
- />Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
- />Present address: Division of Molecular Pathology, Research Institute for Biomedical Sciences, Tokyo University of Science, 2669 Yamazaki, Noda, Chiba 278-0022 Japan
| | - Gen Hamanaka
- />Tateyama Marine Laboratory, Marine and Coastal Research Center, Ochanomizu University, Kou-yatsu 11, Tateyama, Chiba 294-0301 Japan
| | - Kazutoshi Shindo
- />Department of Food and Nutrition, Japan Women’s University, 2-8-1, Mejirodai, Bunkyo-ku, Tokyo 112-8681 Japan
| | - Atsuko Shimada
- />Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
| | - Mariko Kondo
- />Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa 238-0225 Japan
| | - Takanori Narita
- />Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
- />Present address: Laboratory of Veterinary Biochemistry, Nihon University College of Bioresource Sciences, 1866 Kameino, Fujisawa, Kanagawa 252-0880 Japan
| | - Masato Kiyomoto
- />Tateyama Marine Laboratory, Marine and Coastal Research Center, Ochanomizu University, Kou-yatsu 11, Tateyama, Chiba 294-0301 Japan
| | - Yohei Katsuyama
- />Department of Biotechnology, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-8657 Japan
| | - Yasuo Ohnishi
- />Department of Biotechnology, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-8657 Japan
| | - Naoki Irie
- />Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
| | - Hiroyuki Takeda
- />Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan
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17
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Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014; 244:239-53. [PMID: 25255879 DOI: 10.1002/dvdy.24195] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
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Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
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18
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Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014. [PMID: 25255879 DOI: 10.1002/dvdy.24195(2014)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
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Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
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19
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Rothschild SC, Lahvic J, Francescatto L, McLeod JJA, Burgess SM, Tombes RM. CaMK-II activation is essential for zebrafish inner ear development and acts through Delta-Notch signaling. Dev Biol 2013; 381:179-88. [PMID: 23747599 DOI: 10.1016/j.ydbio.2013.05.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 11/30/2022]
Abstract
Zebrafish inner ear development is characterized by the crystallization of otoliths onto immotile kinocilia that protrude from sensory "hair" cells. The stereotypical formation of these sensory structures is dependent on the expression of key patterning genes and on Ca2+ signals. One potential target of Ca2+ signaling in the inner ear is the type II Ca2+/calmodulin-dependent protein kinase (CaMK-II), which is preferentially activated in hair cells, with intense activation at the base of kinocilia. In zebrafish, CaMK-II is encoded by seven genes; the expression of one of these genes (camk2g1) is enriched in hair cells. The suppression of camk2g1 expression by antisense morpholino oligonucleotides or inhibition of CaMK-II activation by the pharmacological antagonist, KN-93, results in aberrant otolith formation without preventing cilia formation. In fact, CaMK-II suppression results in additional ciliated hair cells and altered levels of Delta-Notch signaling members. DeltaA and deltaD transcripts are increased and DeltaD protein accumulates in hair cells of CaMK-II morphants, indicative of defective recycling and/or exocytosis. Our findings indicate that CaMK-II plays a critical role in the developing ear, influencing cell differentiation through extranuclear effects on Delta-Notch signaling. Continued expression and activation of CaMK-II in maculae and cristae in older embryos suggests continued roles in auditory sensory maturation and transduction.
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Affiliation(s)
- Sarah C Rothschild
- Department of Biology, Virginia Commonwealth University, Richmond, VA, USA
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20
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Zamora LY, Lu Z. Alcohol-induced morphological deficits in the development of octavolateral organs of the zebrafish (Danio rerio). Zebrafish 2013; 10:52-61. [PMID: 23461415 DOI: 10.1089/zeb.2012.0830] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Prenatal alcohol exposure is known to have many profound detrimental effects on human fetal development (fetal alcohol spectrum disorders), which may manifest as lifelong disabilities. However, how alcohol affects the auditory/vestibular system is still largely unknown. This is the first study to investigate morphological effects of alcohol on the developing octavolateral system (the inner ear and lateral line) using the zebrafish, Danio rerio. Zebrafish embryos of 2 hours post fertilization (hpf) were treated in 2% alcohol for 48 hours and screened at 72 hpf for morphological defects of the inner ear and lateral line. Octavolateral organs from both alcohol-treated and control zebrafish were examined using light, confocal, and scanning electron microscopy. We observed several otolith phenotypes for alcohol-treated zebrafish including zero, one, two abnormal, two normal, and multiple otoliths. Results of this study show that alcohol treatment during early development impairs the inner ear (smaller ear, abnormal otoliths, and fewer sensory hair cells) and the lateral line (smaller neuromasts, fewer neuromasts and hair cells per neuromast, and shorter kinocilia of hair cells). Early embryonic alcohol exposure may also result in defects in hearing, balance, and hydrodynamic function of zebrafish.
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Affiliation(s)
- Lilliann Y Zamora
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA
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21
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Obholzer N, Swinburne IA, Schwab E, Nechiporuk AV, Nicolson T, Megason SG. Rapid positional cloning of zebrafish mutations by linkage and homozygosity mapping using whole-genome sequencing. Development 2012; 139:4280-90. [PMID: 23052906 DOI: 10.1242/dev.083931] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Forward genetic screens in zebrafish have identified >9000 mutants, many of which are potential disease models. Most mutants remain molecularly uncharacterized because of the high cost, time and labor investment required for positional cloning. These costs limit the benefit of previous genetic screens and discourage future screens. Drastic improvements in DNA sequencing technology could dramatically improve the efficiency of positional cloning in zebrafish and other model organisms, but the best strategy for cloning by sequencing has yet to be established. Using four zebrafish inner ear mutants, we developed and compared two approaches for 'cloning by sequencing': one based on bulk segregant linkage (BSFseq) and one based on homozygosity mapping (HMFseq). Using BSFseq we discovered that mutations in lmx1b and jagged1b cause abnormal ear morphogenesis. With HMFseq we validated that the disruption of cdh23 abolishes the ear's sensory functions and identified a candidate lesion in lhfpl5a predicted to cause nonsyndromic deafness. The success of HMFseq shows that the high intrastrain polymorphism rate in zebrafish eliminates the need for time-consuming map crosses. Additionally, we analyzed diversity in zebrafish laboratory strains to find areas of elevated diversity and areas of fixed homozygosity, reinforcing recent findings that genome diversity is clustered. We present a database of >15 million sequence variants that provides much of this approach's power. In our four test cases, only a single candidate single nucleotide polymorphism (SNP) remained after subtracting all database SNPs from a mutant's critical region. The saturation of the common SNP database and our open source analysis pipeline MegaMapper will improve the pace at which the zebrafish community makes unique discoveries relevant to human health.
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Affiliation(s)
- Nikolaus Obholzer
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
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22
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Wu D, Freund JB, Fraser SE, Vermot J. Mechanistic basis of otolith formation during teleost inner ear development. Dev Cell 2011; 20:271-8. [PMID: 21316594 DOI: 10.1016/j.devcel.2010.12.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 10/13/2010] [Accepted: 11/27/2010] [Indexed: 11/26/2022]
Abstract
Otoliths, which are connected to stereociliary bundles in the inner ear, serve as inertial sensors for balance. In teleostei, otolith development is critically dependent on flow forces generated by beating cilia; however, the mechanism by which flow controls otolith formation remains unclear. Here, we have developed a noninvasive flow probe using optical tweezers and a viscous flow model in order to demonstrate how the observed hydrodynamics influence otolith assembly. We show that rotational flow stirs and suppresses precursor agglomeration in the core of the cilia-driven vortex. The velocity field correlates with the shape of the otolith and we provide evidence that hydrodynamics is actively involved in controlling otolith morphogenesis. An implication of this hydrodynamic effect is that otolith self-assembly is mediated by the balance between Brownian motion and cilia-driven flow. More generally, this flow feature highlights an alternative biological strategy for controlling particle localization in solution.
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Affiliation(s)
- David Wu
- Biological Imaging Center, Beckman Institute, Option in Bioengineering, Caltech, Pasadena, CA 91125, USA
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23
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Malicki J, Avanesov A, Li J, Yuan S, Sun Z. Analysis of cilia structure and function in zebrafish. Methods Cell Biol 2011; 101:39-74. [PMID: 21550439 DOI: 10.1016/b978-0-12-387036-0.00003-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The cilium, a previously little studied cell surface protrusion, has emerged as an important organelle in vertebrate cells. This tiny structure is essential for normal embryonic development, including the formation of left-right asymmetry, limb morphogenesis, and the differentiation of sensory cells. In the adult, cilia also function in a variety of processes, such as the survival of photoreceptor cells, and the homeostasis in several tissues, including the epithelia of nephric ducts. Human ciliary malfunction is associated with situs inversus, kidney cysts, polydactyly, blindness, mental retardation, obesity, and many other abnormalities. The genetic accessibility and optical transparency of the zebrafish make it an excellent vertebrate model system to study cilia biology. In this chapter, we describe the morphology and distribution of cilia in zebrafish embryonic and larval organs. We also provide essential protocols to analyze cilia formation and function.
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Affiliation(s)
- Jarema Malicki
- Division of Craniofacial and Molecular Genetics, Tufts University, Massachusetts, USA
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24
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Petko JA, Kabbani N, Frey C, Woll M, Hickey K, Craig M, Canfield VA, Levenson R. Proteomic and functional analysis of NCS-1 binding proteins reveals novel signaling pathways required for inner ear development in zebrafish. BMC Neurosci 2009; 10:27. [PMID: 19320994 PMCID: PMC2679751 DOI: 10.1186/1471-2202-10-27] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 03/25/2009] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The semicircular canals, a subdivision of the vestibular system of the vertebrate inner ear, function as sensors of angular acceleration. Little is currently known, however, regarding the underlying molecular mechanisms that govern the development of this intricate structure. Zebrafish represent a particularly tractable model system for the study of inner ear development. This is because the ear can be easily visualized during early embryogenesis, and both forward and reverse genetic techniques are available that can be applied to the discovery of novel genes that contribute to proper ear development. We have previously shown that in zebrafish, the calcium sensing molecule neuronal calcium sensor-1 (NCS-1) is required for semicircular canal formation. The function of NCS-1 in regulating semicircular canal formation has not yet been elucidated. RESULTS We initiated a multistep functional proteomic strategy to identify neuronal calcium sensor-1 (NCS-1) binding partners (NBPs) that contribute to inner ear development in zebrafish. By performing a Y2H screen in combination with literature and database searches, we identified 10 human NBPs. BLAST searches of the zebrafish EST and genomic databases allowed us to clone zebrafish orthologs of each of the human NBPs. By investigating the expression profiles of zebrafish NBP mRNAs, we identified seven that were expressed in the developing inner ear and overlapped with the ncs-1a expression profile. GST pulldown experiments confirmed that selected NBPs interacted with NCS-1, while morpholino-mediated knockdown experiments demonstrated an essential role for arf1, pi4kbeta, dan, and pink1 in semicircular canal formation. CONCLUSION Based on their functional profiles, the hypothesis is presented that Ncs-1a/Pi4kbeta/Arf1 form a signaling pathway that regulates secretion of molecular components, including Dan and Bmp4, that are required for development of the vestibular apparatus. A second set of NBPs, consisting of Pink1, Hint2, and Slc25a25, are destined for localization in mitochondria. Our findings reveal a novel signalling pathway involved in development of the semicircular canal system, and suggest a previously unrecognized role for NCS-1 in mitochondrial function via its association with several mitochondrial proteins.
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Affiliation(s)
- Jessica A Petko
- Department of Pharmacology, Penn State College of Medicine, 500 University Drive, Hershey PA 17033, USA.
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