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Navajas Acedo J. Complete persistence of the primary somatosensory system in zebrafish. Dev Biol 2024:S0012-1606(24)00115-5. [PMID: 39021074 DOI: 10.1016/j.ydbio.2024.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/20/2024] [Accepted: 05/07/2024] [Indexed: 07/20/2024]
Abstract
The somatosensory system detects peripheral stimuli that are translated into behaviors necessary for survival. Fishes and amphibians possess two somatosensory systems in the trunk: the primary somatosensory system, formed by the Rohon-Beard neurons, and the secondary somatosensory system, formed by the neural crest cell-derived neurons of the Dorsal Root Ganglia. Rohon-Beard neurons have been characterized as a transient population that mostly disappears during the first days of life and is functionally replaced by the Dorsal Root Ganglia. Here, I follow Rohon-Beard neurons in vivo and show that the entire repertoire remains present in zebrafish from 1-day post-fertilization until the juvenile stage, 15-days post-fertilization. These data indicate that zebrafish retain two complete somatosensory systems until at least a developmental stage when the animals display complex behavioral repertoires.
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Affiliation(s)
- Joaquín Navajas Acedo
- Biozentrum at University of Basel, Spitalstrasse 41, Basel, Switzerland; Allen Discovery Center for Cell Lineage Tracing, University of Washington, Seattle, WA, USA.
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2
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Tuz-Sasik MU, Manuel R, Boije H. Efferent axons in the zebrafish lateral line degenerate following sensory hair cell ablation. Mol Cell Neurosci 2023; 127:103900. [PMID: 37714280 DOI: 10.1016/j.mcn.2023.103900] [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: 07/06/2023] [Revised: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 09/17/2023] Open
Abstract
The zebrafish lateral line is a frequently used model to study the mechanisms behind peripheral neuronal innervation of sensory organs and the regeneration thereof. The lateral line system consists of neuromasts, a cluster of protruding hair cells, which are innervated by sensory afferent and modulatory efferent neurons. These flow-sensing hair cells are similar to the hair cells in the mammalian ear. Though, while hair cell loss in humans is irreversible, the zebrafish neuromasts are regarded as the fastest regenerating structure in vertebrates, making them an ideal model to study regeneration. However, one component of the lateral line system, the efferent projections, has largely been omitted in regenerative studies. Here, for the first time, we bring insights into the fate of efferent axons during ablation and regeneration of the hair cells in the zebrafish lateral line. Our behavioral analysis showed functional recovery of hair cells and sensory transmission within 48 h and their regeneration were in line with previous studies. Analysis of the inhibitory efferent projections revealed that in approximately half the cases the inhibitory efferent axons degenerated, which was never observed for the sensory afferent axons. Quantification of hair cells following ablation suggests that the presence of mature hair cells in the neuromast may prevent axon degeneration. Within 120 h, degenerated efferent axons regenerated along the axonal tract of the lateral line. Reanalysis of published single cell neuromast data hinted to a role for Bdnf in the survival of efferent axons. However, sequestering Bdnf, blocking the Trk-receptors, and inhibiting the downstream ERK-signaling, did not induce axon degeneration, indicating that efferent survival is not mediated through neurotrophic factors. To further explore the relation between hair cells and efferent projections, we generated atoh1a mutants, where mature hair cells never form. In larvae lacking hair cells, inhibitory efferent projections were still present, following the tract of the sensory afferent without displaying any innervation. Our study reveal the fate of efferent innervation following hair cell ablation and provide insights into the inherent differences in regeneration between neurons in the peripheral and central nervous system.
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Affiliation(s)
- Melek Umay Tuz-Sasik
- Department of Immunology, Genetics and Pathology, Cell and Neurobiology, Uppsala University, Uppsala, Sweden
| | - Remy Manuel
- Department of Immunology, Genetics and Pathology, Cell and Neurobiology, Uppsala University, Uppsala, Sweden
| | - Henrik Boije
- Department of Immunology, Genetics and Pathology, Cell and Neurobiology, Uppsala University, Uppsala, Sweden.
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Elorza Ridaura I, Sorrentino S, Moroni L. Parallels between the Developing Vascular and Neural Systems: Signaling Pathways and Future Perspectives for Regenerative Medicine. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2101837. [PMID: 34693660 PMCID: PMC8655224 DOI: 10.1002/advs.202101837] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 07/23/2021] [Indexed: 05/10/2023]
Abstract
Neurovascular disorders, which involve the vascular and nervous systems, are common. Research on such disorders usually focuses on either vascular or nervous components, without looking at how they interact. Adopting a neurovascular perspective is essential to improve current treatments. Therefore, comparing molecular processes known to be involved in both systems separately can provide insight into promising areas of future research. Since development and regeneration share many mechanisms, comparing signaling molecules involved in both the developing vascular and nervous systems and shedding light to those that they have in common can reveal processes, which have not yet been studied from a regenerative perspective, yet hold great potential. Hence, this review discusses and compares processes involved in the development of the vascular and nervous systems, in order to provide an overview of the molecular mechanisms, which are most promising with regards to treatment for neurovascular disorders. Vascular endothelial growth factor, semaphorins, and ephrins are found to hold the most potential, while fibroblast growth factor, bone morphogenic protein, slits, and sonic hedgehog are shown to participate in both the developing vascular and nervous systems, yet have not been studied at the neurovascular level, therefore being of special interest for future research.
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Affiliation(s)
- Idoia Elorza Ridaura
- Complex Tissue Regeneration DepartmentMERLN Institute for Technology‐Inspired Regenerative MedicineMaastricht UniversityUniversiteitssingel 40Maastricht6229ERThe Netherlands
| | - Stefano Sorrentino
- CNR Nanotec – Institute of NanotechnologyCampus Ecotekne, via MonteroniLecce73100Italy
| | - Lorenzo Moroni
- Complex Tissue Regeneration DepartmentMERLN Institute for Technology‐Inspired Regenerative MedicineMaastricht UniversityUniversiteitssingel 40Maastricht6229ERThe Netherlands
- CNR Nanotec – Institute of NanotechnologyCampus Ecotekne, via MonteroniLecce73100Italy
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4
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Levin M, Ribera AB. Editorial: Interplay Between Ion Channels, the Nervous System, and Embryonic Development. Front Mol Neurosci 2021; 14:618815. [PMID: 33841097 PMCID: PMC8024538 DOI: 10.3389/fnmol.2021.618815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 03/04/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael Levin
- Department of Biology and Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Angeles B Ribera
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Denver, CO, United States
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5
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Kteeba SM, El-Ghobashy AE, El-Adawi HI, El-Rayis OA, Sreevidya VS, Guo L, Svoboda KR. Exposure to ZnO nanoparticles alters neuronal and vascular development in zebrafish: Acute and transgenerational effects mitigated with dissolved organic matter. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 242:433-448. [PMID: 30005256 DOI: 10.1016/j.envpol.2018.06.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 05/21/2018] [Accepted: 06/09/2018] [Indexed: 06/08/2023]
Abstract
Exposure to ZnO-nanoparticles (NPs) in embryonic zebrafish reduces hatching rates which can be mitigated with dissolved organic material (DOM). Although hatching rate can be a reliable indicator of toxicity and DOM mitigation potential, a fish that has been exposed to ZnO-NPs or any other toxicant may also exhibit other abnormal phenotypes not readily detected by the unaided eye. In this study, we moved beyond hatching rate analysis to investigate the consequences of ZnO-NPs exposure on the nervous and vascular systems in developing zebrafish. Zebrafish exposed to ZnO-NPs (1-100 ppm) exhibited an array of cellular phenotypes including: abnormal secondary motoneuron (SMN) axonal projections, abnormal dorsal root ganglion development and abnormal blood vessel development. Dissolved Zn (<10 kDa) exposure also caused abnormal SMN axonal projections, but to a lesser extent than ZnO-NPs. The ZnO-NPs-induced abnormal phenotypes were reversed in embryos concurrently exposed with various types of DOM. In these acute mitigation exposure experiments, humic acid and carbohydrate, along with natural organic matter obtained from the Suwannee River in Georgia and Milwaukee River in Wisconsin, were the best mitigators of ZnO-NPs-induced motoneuron toxicity at 96 h post fertilization. Further experiments were performed to determine if the ZnO-NPs-induced, abnormal axonal phenotypes and the DOM mitigated axonal phenotypes could persist across generations. Abnormal SMN axon phenotypes caused by ZnO-NPs-exposure were detected in F1 and F2 generations. These are fish that have not been directly exposed to ZnO-NPs. Fish mitigated with DOM during the acute exposure (F0 generation) had a reduction in abnormal motoneuron axon errors in larvae of subsequent generations. Therefore, ZnO-NPs exposure results in neurotoxicity in developing zebrafish which can persist from one generation to the next. Mitigation with DOM can reverse the abnormal phenotypes in an acute embryonic exposure context, as well as across generations, resulting in healthy fish.
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Affiliation(s)
- Shimaa M Kteeba
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E. Greenfield Avenue, Milwaukee, WI, 53204, USA; Zoology Department, Faculty of Science, Damietta University, New Damietta 34511, Damietta, Egypt
| | - Ahmed E El-Ghobashy
- Zoology Department, Faculty of Science, Damietta University, New Damietta 34511, Damietta, Egypt
| | - Hala I El-Adawi
- Medical Biotechnology Department, Genetic Engineering and Biotech Institute, Borg El-Arab City for Scientific Research, Universities and Research District Sector, New Borg El-Arab 21934, Alexandria, Egypt
| | - Osman A El-Rayis
- Oceanography Department, Faculty of Science, Alexandria University, Moharrem Bek 21511, Alexandria, Egypt
| | - Virinchipuram S Sreevidya
- Joseph J. Zilber School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, WI, 53205, USA
| | - Laodong Guo
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E. Greenfield Avenue, Milwaukee, WI, 53204, USA
| | - Kurt R Svoboda
- Joseph J. Zilber School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, WI, 53205, USA.
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The Dynamics of Neurosteroids and Sex-Related Hormones in the Pathogenesis of Alzheimer’s Disease. Neuromolecular Med 2018; 20:215-224. [DOI: 10.1007/s12017-018-8493-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/28/2018] [Indexed: 12/11/2022]
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The Potential of Gonadal Hormone Signalling Pathways as Therapeutics for Dementia. J Mol Neurosci 2016; 60:336-348. [PMID: 27525638 DOI: 10.1007/s12031-016-0813-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/01/2016] [Indexed: 12/17/2022]
Abstract
Dementia is an ever-expanding problem facing an ageing society. Currently, there is a sharp paucity of treatment strategies. It has long been known that sex hormones, namely 17β-estradiol and testosterone, possess neuroprotective- and cognitive-enhancing qualities. However, certain lacunae in the knowledge underlying their molecular mechanisms have delayed their use as treatment strategies in dementia. With recent advancements in pharmacology and molecular biology, especially in the development of safer selective oestrogen receptor modulators and the recent discovery of the small-molecule brain-derived neurotrophic factor receptor agonist, 7,8-dihydroxyflavone, the exploitation of these signalling pathways for clinical use has become possible. This review aims to adumbrate the evidence and hurdles underscoring the use of sex hormones in the treatment of dementia as well as discussing some direction that is required to advance the translation of evidence into practise.
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Du X, Hill R. 7,8-Dihydroxyflavone as a pro-neurotrophic treatment for neurodevelopmental disorders. Neurochem Int 2015. [DOI: 10.1016/j.neuint.2015.07.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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9
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Newbern JM. Molecular control of the neural crest and peripheral nervous system development. Curr Top Dev Biol 2015; 111:201-31. [PMID: 25662262 DOI: 10.1016/bs.ctdb.2014.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A transient and unique population of multipotent stem cells, known as neural crest cells (NCCs), generate a bewildering array of cell types during vertebrate development. An attractive model among developmental biologists, the study of NCC biology has provided a wealth of knowledge regarding the cellular and molecular mechanisms important for embryogenesis. Studies in numerous species have defined how distinct phases of NCC specification, proliferation, migration, and survival contribute to the formation of multiple functionally distinct organ systems. NCC contributions to the peripheral nervous system (PNS) are well known. Critical developmental processes have been defined that provide outstanding models for understanding how extracellular stimuli, cell-cell interactions, and transcriptional networks cooperate to direct cellular diversification and PNS morphogenesis. Dissecting the complex extracellular and intracellular mechanisms that mediate the formation of the PNS from NCCs may have important therapeutic implications for neurocristopathies, neuropathies, and certain forms of cancer.
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Affiliation(s)
- Jason M Newbern
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA.
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10
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Non-cell-autonomous mechanism of activity-dependent neurotransmitter switching. Neuron 2014; 82:1004-16. [PMID: 24908484 DOI: 10.1016/j.neuron.2014.04.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2014] [Indexed: 11/21/2022]
Abstract
Activity-dependent neurotransmitter switching engages genetic programs regulating transmitter synthesis, but the mechanism by which activity is transduced is unknown. We suppressed activity in single neurons in the embryonic spinal cord to determine whether glutamate-gamma-aminobutyric acid (GABA) switching is cell autonomous. Transmitter respecification did not occur, suggesting that it is homeostatically regulated by the level of activity in surrounding neurons. Graded increase in the number of silenced neurons in cultures led to graded decrease in the number of neurons expressing GABA, supporting non-cell-autonomous transmitter switching. We found that brain-derived neurotrophic factor (BDNF) is expressed in the spinal cord during the period of transmitter respecification and that spike activity causes release of BDNF. Activation of TrkB receptors triggers a signaling cascade involving JNK-mediated activation of cJun that regulates tlx3, a glutamate/GABA selector gene, accounting for calcium-spike BDNF-dependent transmitter switching. Our findings identify a molecular mechanism for activity-dependent respecification of neurotransmitter phenotype in developing spinal neurons.
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De Felice E, Porreca I, Alleva E, De Girolamo P, Ambrosino C, Ciriaco E, Germanà A, Sordino P. Localization of BDNF expression in the developing brain of zebrafish. J Anat 2014; 224:564-74. [PMID: 24588510 DOI: 10.1111/joa.12168] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2014] [Indexed: 12/14/2022] Open
Abstract
The brain-derived neurotrophic factor (BDNF) gene is expressed in differentiating and post-mitotic neurons of the zebrafish embryo, where it has been implicated in Huntington's disease. Little is known, however, about the full complement of neuronal cell types that express BDNF in this important vertebrate model. Here, we further explored the transcriptional profiles during the first week of development using real-time quantitative polymerase chain reaction (RT-qPCR) and whole-mount in situ hybridization (WISH). RT-qPCR results revealed a high level of maternal contribution followed by a steady increase of zygotic transcription, consistent with the notion of a prominent role of BDNF in neuronal maturation and maintenance. Based on WISH, we demonstrate for the first time that BDNF expression in the developing brain of zebrafish is structure specific. Anatomical criteria and co-staining with genetic markers (shh, pax2a, emx1, krox20, lhx2b and lhx9) visualized major topological domains of BDNF-positive cells in the pallium, hypothalamus, posterior tuberculum and optic tectum. Moreover, the relative timing of BDNF transcription in the eye and tectum may illustrate a mechanism for coordinated development of the retinotectal system. Taken together, our results are compatible with a local delivery and early role of BDNF in the developing brain of zebrafish, adding basic knowledge to the study of neurotrophin functions in neural development and disease.
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Affiliation(s)
- E De Felice
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Naples, Italy; Department of Morphology, Biochemistry, Physiology and Animal Productions, Section of Morphology, University of Messina, Messina, Italy
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12
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Interplay between electrical activity and bone morphogenetic protein signaling regulates spinal neuron differentiation. Proc Natl Acad Sci U S A 2012; 109:16336-41. [PMID: 22991474 DOI: 10.1073/pnas.1202818109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A gradient of bone morphogenetic proteins (BMPs) along the dorsoventral axis of the spinal cord is necessary for the specification of dorsal neurons. Concurrently, a gradient of calcium-mediated electrical activity is present in the developing spinal cord but in an opposing ventrodorsal direction. Whether BMPs and electrical activity interact in embryonic spinal neurons remains unknown. We show that BMP decreases electrical activity by enhancing p38 MAPK-mediated negative modulation of voltage-gated sodium channels. In turn, electrical activity affects the phosphorylation status and nuclear level of activated Smads, the canonical components of BMP signaling. This interaction between calcium spike activity and BMP signaling regulates the specification of the dorsal commissural spinal neuron phenotype. The present study identifies an unexpected interplay between BMPs and electrical activity that is critical for decoding the morphogen gradient during spinal neuron differentiation.
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Won YJ, Ono F, Ikeda SR. Characterization of Na+ and Ca2+ channels in zebrafish dorsal root ganglion neurons. PLoS One 2012; 7:e42602. [PMID: 22880050 PMCID: PMC3411820 DOI: 10.1371/journal.pone.0042602] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 07/10/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Dorsal root ganglia (DRG) somata from rodents have provided an excellent model system to study ion channel properties and modulation using electrophysiological investigation. As in other vertebrates, zebrafish (Danio rerio) DRG are organized segmentally and possess peripheral axons that bifurcate into each body segment. However, the electrical properties of zebrafish DRG sensory neurons, as compared with their mammalian counterparts, are relatively unexplored because a preparation suitable for electrophysiological studies has not been available. METHODOLOGY/PRINCIPAL FINDINGS We show enzymatically dissociated DRG neurons from juvenile zebrafish expressing Isl2b-promoter driven EGFP were easily identified with fluorescence microscopy and amenable to conventional whole-cell patch-clamp studies. Two kinetically distinct TTX-sensitive Na(+) currents (rapidly- and slowly-inactivating) were discovered. Rapidly-inactivating I(Na) were preferentially expressed in relatively large neurons, while slowly-inactivating I(Na) was more prevalent in smaller DRG neurons. RT-PCR analysis suggests zscn1aa/ab, zscn8aa/ab, zscn4ab and zscn5Laa are possible candidates for these I(Na) components. Voltage-gated Ca(2+) currents (I(Ca)) were primarily (87%) comprised of a high-voltage activated component arising from ω-conotoxin GVIA-sensitive Ca(V)2.2 (N-type) Ca(2+) channels. A few DRG neurons (8%) displayed a miniscule low-voltage-activated component. I(Ca) in zebrafish DRG neurons were modulated by neurotransmitters via either voltage-dependent or -independent G-protein signaling pathway with large cell-to-cell response variability. CONCLUSIONS/SIGNIFICANCE Our present results indicate that, as in higher vertebrates, zebrafish DRG neurons are heterogeneous being composed of functionally distinct subpopulations that may correlate with different sensory modalities. These findings provide the first comparison of zebrafish and rodent DRG neuron electrical properties and thus provide a basis for future studies.
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Affiliation(s)
- Yu-Jin Won
- Section on Transmitter Signaling, Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Fumihito Ono
- Section on Model Synaptic Systems, Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stephen R. Ikeda
- Section on Transmitter Signaling, Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, United States of America
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Mo W, Nicolson T. Both pre- and postsynaptic activity of Nsf prevents degeneration of hair-cell synapses. PLoS One 2011; 6:e27146. [PMID: 22073277 PMCID: PMC3207842 DOI: 10.1371/journal.pone.0027146] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 10/11/2011] [Indexed: 01/27/2023] Open
Abstract
Vesicle fusion contributes to the maintenance of synapses in the nervous system by mediating synaptic transmission, release of neurotrophic factors, and trafficking of membrane receptors. N-ethylmaleimide-sensitive factor (NSF) is indispensible for dissociation of the SNARE-complex following vesicle fusion. Although NSF function has been characterized extensively in vitro, the in vivo role of NSF in vertebrate synaptogenesis is relatively unexplored. Zebrafish possess two nsf genes, nsf and nsfb. Here, we examine the function of either Nsf or Nsfb in the pre- and postsynaptic cells of the zebrafish lateral line organ and demonstrate that Nsf, but not Nsfb, is required for maintenance of afferent synapses in hair cells. In addition to peripheral defects in nsf mutants, neurodegeneration of glutamatergic synapses in the central nervous system also occurs in the absence of Nsf function. Expression of an nsf transgene in a null background indicates that stabilization of synapses requires Nsf function in both hair cells and afferent neurons. To identify potential targets of Nsf-mediated fusion, we examined the expression of genes implicated in stabilizing synapses and found that transcripts for multiple genes including brain-derived neurotrophic factor (bdnf) were significantly reduced in nsf mutants. With regard to trafficking of BDNF, we observed a striking accumulation of BDNF in the neurites of nsf mutant afferent neurons. In addition, injection of recombinant BDNF protein partially rescued the degeneration of afferent synapses in nsf mutants. These results establish a role for Nsf in the maintenance of synaptic contacts between hair cells and afferent neurons, mediated in part via the secretion of trophic signaling factors.
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Affiliation(s)
- Weike Mo
- Howard Hughes Medical Institute, Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Teresa Nicolson
- Howard Hughes Medical Institute, Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, Oregon, United States of America
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