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Saccomanno V, Love H, Sylvester A, Li WC. The early development and physiology of Xenopus laevis tadpole lateral line system. J Neurophysiol 2021; 126:1814-1830. [PMID: 34705593 DOI: 10.1152/jn.00618.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Xenopus laevis has a lateral line mechanosensory system throughout its full life cycle, and a previous study on prefeeding stage tadpoles revealed that it may play a role in motor responses to both water suction and water jets. Here, we investigated the physiology of the anterior lateral line system in newly hatched tadpoles and the motor outputs induced by its activation in response to brief suction stimuli. High-speed videoing showed tadpoles tended to turn and swim away when strong suction was applied close to the head. The lateral line neuromasts were revealed by using DASPEI staining, and their inactivation with neomycin eliminated tadpole motor responses to suction. In immobilized preparations, suction or electrically stimulating the anterior lateral line nerve reliably initiated swimming but the motor nerve discharges implicating turning was observed only occasionally. The same stimulation applied during ongoing fictive swimming produced a halting response. The anterior lateral line nerve showed spontaneous afferent discharges at rest and increased activity during stimulation. Efferent activities were only recorded during tadpole fictive swimming and were largely synchronous with the ipsilateral motor nerve discharges. Finally, calcium imaging identified neurons with fluorescence increase time-locked with suction stimulation in the hindbrain and midbrain. A cluster of neurons at the entry point of the anterior lateral line nerve in the dorsolateral hindbrain had the shortest latency in their responses, supporting their potential sensory interneuron identity. Future studies need to reveal how the lateral line sensory information is processed by the central circuit to determine tadpole motor behavior.NEW & NOTEWORTHY We studied Xenopus tadpole motor responses to anterior lateral line stimulation using high-speed videos, electrophysiology and calcium imaging. Activating the lateral line reliably started swimming. At high stimulation intensities, turning was observed behaviorally but suitable motor nerve discharges were seen only occasionally in immobilized tadpoles. Suction applied during swimming produced a halting response. We analyzed afferent and efferent activities of the tadpole anterior lateral line nerve and located sensory interneurons using calcium imaging.
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Affiliation(s)
- Valentina Saccomanno
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom.,Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Heather Love
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom
| | - Amy Sylvester
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom
| | - Wen-Chang Li
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom
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Bao B, He Y, Tang D, Li W, Li H. Inhibition of H3K27me3 Histone Demethylase Activity Prevents the Proliferative Regeneration of Zebrafish Lateral Line Neuromasts. Front Mol Neurosci 2017; 10:51. [PMID: 28348517 PMCID: PMC5346882 DOI: 10.3389/fnmol.2017.00051] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/14/2017] [Indexed: 01/01/2023] Open
Abstract
The H3K27 demethylases are involved in a variety of biological processes, including cell differentiation, proliferation, and cell death by regulating transcriptional activity. However, the function of H3K27 demethylation in the field of hearing research is poorly understood. Here, we investigated the role of H3K27me3 histone demethylase activity in hair cell regeneration using an in vivo animal model. Our data showed that pharmacologic inhibition of H3K27 demethylase activity with the specific small-molecule inhibitor GSK-J4 decreased the number of regenerated hair cells in response to neomycin damage. Furthermore, inhibition of H3K27me3 histone demethylase activity dramatically suppressed cell proliferation and activated caspase-3 levels in the regenerating neuromasts of the zebrafish lateral line. GSK-J4 administration also increased the expression of p21 and p27 in neuromast cells and inhibited the ERK signaling pathway. Collectively, our findings indicate that H3K27me3 demethylation is a key epigenetic regulator in the process of hair cell regeneration in zebrafish and suggest that H3K27me3 histone demethylase activity might be a novel therapeutic target for the treatment of hearing loss.
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Affiliation(s)
- Beier Bao
- State Key Laboratory of Medical Neurobiology, Medical College of Fudan University Shanghai, China
| | - Yingzi He
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China; Key Laboratory of Hearing Medicine of National Health and Family Planning CommissionShanghai, China
| | - Dongmei Tang
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China; Key Laboratory of Hearing Medicine of National Health and Family Planning CommissionShanghai, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China; Key Laboratory of Hearing Medicine of National Health and Family Planning CommissionShanghai, China
| | - Huawei Li
- State Key Laboratory of Medical Neurobiology, Medical College of Fudan UniversityShanghai, China; ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China; Key Laboratory of Hearing Medicine of National Health and Family Planning CommissionShanghai, China; Institutes of Biomedical Science, Fudan UniversityShanghai, China; The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan UniversityShanghai, China
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Cruz IA, Kappedal R, Mackenzie SM, Hailey DW, Hoffman TL, Schilling TF, Raible DW. Robust regeneration of adult zebrafish lateral line hair cells reflects continued precursor pool maintenance. Dev Biol 2015; 402:229-38. [PMID: 25869855 DOI: 10.1016/j.ydbio.2015.03.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 03/03/2015] [Accepted: 03/27/2015] [Indexed: 01/08/2023]
Abstract
We have examined lateral line hair cell and support cell maintenance in adult zebrafish when growth is largely complete. We demonstrate that adult zebrafish not only replenish hair cells after a single instance of hair cell damage, but also maintain hair cells and support cells after multiple rounds of damage and regeneration. We find that hair cells undergo continuous turnover in adult zebrafish in the absence of damage. We identify mitotically-distinct support cell populations and show that hair cells regenerate from underlying support cells in a region-specific manner. Our results demonstrate that there are two distinct support cell populations in the lateral line, which may help explain why zebrafish hair cell regeneration is extremely robust, retained throughout life, and potentially unlimited in regenerative capacity.
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Affiliation(s)
- Ivan A Cruz
- Molecular Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA; Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Ryan Kappedal
- Department of Statistics, University of Washington, Seattle, WA 98195, USA
| | - Scott M Mackenzie
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA; Neurobiology and Behavior Graduate Program, University of Washington, Seattle, WA 98195, USA
| | - Dale W Hailey
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Trevor L Hoffman
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697-2300, USA; Kaiser Permanente, 5971 Venice Boulevard, West Los Angeles, CA 90034, USA
| | - Thomas F Schilling
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697-2300, USA
| | - David W Raible
- Molecular Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA; Department of Biological Structure, University of Washington, Seattle, WA 98195, USA; Neurobiology and Behavior Graduate Program, University of Washington, Seattle, WA 98195, USA.
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