1
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Guo C, Webb SE, Chan CM, Miller AL. TPC2-mediated Ca 2+ signaling is required for axon extension in caudal primary motor neurons in zebrafish embryos. J Cell Sci 2020; 133:jcs244780. [PMID: 32546534 DOI: 10.1242/jcs.244780] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 05/27/2020] [Indexed: 12/13/2022] Open
Abstract
The role of two-pore channel type 2 (TPC2, encoded by tcpn2)-mediated Ca2+ release was recently characterized in zebrafish during establishment of the early spinal circuitry, one of the key events in the coordination of neuromuscular activity. Here, we extend our study to investigate the in vivo role of TPC2 in the regulation of caudal primary motor neuron (CaP) axon extension. We used a combination of TPC2 knockdown with a translation-blocking morpholino antisense oligonucleotide (MO), TPC2 knockout via the generation of a tpcn2dhkz1a mutant line of zebrafish using CRISPR/Cas9 gene-editing and pharmacological inhibition of TPC2 via incubation with bafilomycin A1 (an H+-ATPase inhibitor) or trans-ned-19 (an NAADP receptor antagonist), and showed that these treatments attenuated CaP Ca2+ signaling and inhibited axon extension. We also characterized the expression of an arc1-like transcript in CaPs grown in primary culture. MO-mediated knockdown of ARC1-like in vivo led to attenuation of the Ca2+ transients in the CaP growth cones and an inhibition of axon extension. Together, our new data suggest a link between ARC1-like, TPC2 and Ca2+ signaling during axon extension in zebrafish.
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Affiliation(s)
- Chenxi Guo
- Division of Life Science and State Key Laboratory for Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Sarah E Webb
- Division of Life Science and State Key Laboratory for Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Ching Man Chan
- Division of Life Science and State Key Laboratory for Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Andrew L Miller
- Division of Life Science and State Key Laboratory for Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
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2
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Harris JM, Wang AYD, Boulanger-Weill J, Santoriello C, Foianini S, Lichtman JW, Zon LI, Arlotta P. Long-Range Optogenetic Control of Axon Guidance Overcomes Developmental Boundaries and Defects. Dev Cell 2020; 53:577-588.e7. [PMID: 32516597 PMCID: PMC7375170 DOI: 10.1016/j.devcel.2020.05.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 03/12/2020] [Accepted: 05/11/2020] [Indexed: 01/12/2023]
Abstract
Axons connect neurons together, establishing the wiring architecture of neuronal networks. Axonal connectivity is largely built during embryonic development through highly constrained processes of axon guidance, which have been extensively studied. However, the inability to control axon guidance, and thus neuronal network architecture, has limited investigation of how axonal connections influence subsequent development and function of neuronal networks. Here, we use zebrafish motor neurons expressing a photoactivatable Rac1 to co-opt endogenous growth cone guidance machinery to precisely and non-invasively direct axon growth using light. Axons can be guided over large distances, within complex environments of living organisms, overriding competing endogenous signals and redirecting axons across potent repulsive barriers to construct novel circuitry. Notably, genetic axon guidance defects can be rescued, restoring functional connectivity. These data demonstrate that intrinsic growth cone guidance machinery can be co-opted to non-invasively build new connectivity, allowing investigation of neural network dynamics in intact living organisms.
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Affiliation(s)
- James M. Harris
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Harvard-MIT Division of Health Sciences and Technology, Harvard Medical School, Boston, MA 02115, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA
| | - Andy Yu-Der Wang
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Current Address: Tufts University School of Medicine, Boston, MA 02115, USA
| | - Jonathan Boulanger-Weill
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Cristina Santoriello
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Stem Cell Program and Division of Hematology/Oncology, Children’s Hospital and Dana Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Medical School, Harvard Stem Cell Institute, Stem Cell and Regenerative Biology Department, Harvard University, Boston, MA 02115, USA
| | - Stephan Foianini
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jeff W. Lichtman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Leonard I. Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Stem Cell Program and Division of Hematology/Oncology, Children’s Hospital and Dana Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Medical School, Harvard Stem Cell Institute, Stem Cell and Regenerative Biology Department, Harvard University, Boston, MA 02115, USA
| | - Paola Arlotta
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA.,Lead contact. Correspondence:
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3
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Patel BB, Clark KL, Kozik EM, Dash L, Kuhlman JA, Sakaguchi DS. Isolation and culture of primary embryonic zebrafish neural tissue. J Neurosci Methods 2019; 328:108419. [PMID: 31472190 DOI: 10.1016/j.jneumeth.2019.108419] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Primary cell culture is a valuable tool to utilize in parallel with in vivo studies in order to maximize our understanding of the mechanisms surrounding neurogenesis and central nervous system (CNS) regeneration and plasticity. The zebrafish is an important model for biomedical research and primary neural cells are readily obtainable from their embryonic stages viatissue dissociation. Further, transgenic reporter lines with cell type-specific expression allows for observation of distinct cell populations within the dissociated tissue. NEW METHOD Here, we define an efficient method for ex vivo quantification and characterization of neuronal and glial tissue dissociated from embryonic zebrafish. RESULTS Zebrafish brain dissociated cells have been documented to survive in culture for at least 9 days in vitro (div). Anti-HuC/D and anti-Acetylated Tubulin antibodies were used to identify neurons in culture; at 3 div approximately 48% of cells were HuC/D positive and 85% expressed serotonin, suggesting our protocol can efficiently isolate neurons from whole embryonic zebrafish brains. Live time-lapse imaging was also carried out to analyze cell migration in vitro. COMPARISON WITH EXISTING METHODS Primary cultures of zebrafish neural cells typically have low rates of survivability in vitro. We have developed a culture system that has long term cell viability, enabling direct analysis of cell-cell and cell-extracellular matrix interactions. CONCLUSIONS These results demonstrate a practical method for isolating, dissociating and culturing of embryonic zebrafish neural tissue. This approach could further be utilized to better understand zebrafish regeneration in vitro.
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Affiliation(s)
- Bhavika B Patel
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, United States; Neuroscience Program, United States
| | - Kendra L Clark
- Department of Animal Science, Iowa State University, Ames, IA 50011, United States; Genetics and Genomics Program, United States
| | - Emily M Kozik
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, United States
| | - Linkan Dash
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, United States; Genetics and Genomics Program, United States
| | - Julie A Kuhlman
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, United States.
| | - Donald S Sakaguchi
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, United States; Neuroscience Program, United States.
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4
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Zebrafish as an Emerging Model for Bioassay-Guided Natural Product Drug Discovery for Neurological Disorders. MEDICINES 2019; 6:medicines6020061. [PMID: 31151179 PMCID: PMC6631710 DOI: 10.3390/medicines6020061] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/26/2019] [Accepted: 05/27/2019] [Indexed: 02/06/2023]
Abstract
Most neurodegenerative diseases are currently incurable, with large social and economic impacts. Recently, there has been renewed interest in investigating natural products in the modern drug discovery paradigm as novel, bioactive small molecules. Moreover, the discovery of potential therapies for neurological disorders is challenging and involves developing optimized animal models for drug screening. In contemporary biomedicine, the growing need to develop experimental models to obtain a detailed understanding of malady conditions and to portray pioneering treatments has resulted in the application of zebrafish to close the gap between in vitro and in vivo assays. Zebrafish in pharmacogenetics and neuropharmacology are rapidly becoming a widely used organism. Brain function, dysfunction, genetic, and pharmacological modulation considerations are enhanced by both larval and adult zebrafish. Bioassay-guided identification of natural products using zebrafish presents as an attractive strategy for generating new lead compounds. Here, we see evidence that the zebrafish's central nervous system is suitable for modeling human neurological disease and we review and evaluate natural product research using zebrafish as a vertebrate model platform to systematically identify bioactive natural products. Finally, we review recently developed zebrafish models of neurological disorders that have the potential to be applied in this field of research.
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5
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STIM1 Is Required for Remodeling of the Endoplasmic Reticulum and Microtubule Cytoskeleton in Steering Growth Cones. J Neurosci 2019; 39:5095-5114. [PMID: 31023836 DOI: 10.1523/jneurosci.2496-18.2019] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 11/21/2022] Open
Abstract
The spatial and temporal regulation of calcium signaling in neuronal growth cones is essential for axon guidance. In growth cones, the endoplasmic reticulum (ER) is a significant source of calcium signals. However, it is not clear whether the ER is remodeled during motile events to localize calcium signals in steering growth cones. The expression of the ER-calcium sensor, stromal interacting molecule 1 (STIM1) is necessary for growth cone steering toward the calcium-dependent guidance cue BDNF, with STIM1 functioning to sustain calcium signals through store-operated calcium entry. However, STIM1 is also required for growth cone steering away from semaphorin-3a, a guidance cue that does not activate ER-calcium release, suggesting multiple functions of STIM1 within growth cones (Mitchell et al., 2012). STIM1 also interacts with microtubule plus-end binding proteins EB1/EB3 (Grigoriev et al., 2008). Here, we show that STIM1 associates with EB1/EB3 in growth cones and that STIM1 expression is critical for microtubule recruitment and subsequent ER remodeling to the motile side of steering growth cones. Furthermore, we extend our data in vivo, demonstrating that zSTIM1 is required for axon guidance in actively navigating zebrafish motor neurons, regulating calcium signaling and filopodial formation. These data demonstrate that, in response to multiple guidance cues, STIM1 couples microtubule organization and ER-derived calcium signals, thereby providing a mechanism where STIM1-mediated ER remodeling, particularly in filopodia, regulates spatiotemporal calcium signals during axon guidance.SIGNIFICANCE STATEMENT Defects in both axon guidance and endoplasmic reticulum (ER) function are implicated in a range of developmental disorders. During neuronal circuit development, the spatial localization of calcium signals controls the growth cone cytoskeleton to direct motility. We demonstrate a novel role for stromal interacting molecule 1 (STIM1) in regulating microtubule and subsequent ER remodeling in navigating growth cones. We show that STIM1, an activator of store-operated calcium entry, regulates the dynamics of microtubule-binding proteins EB1/EB3, coupling ER to microtubules, within filopodia, thereby steering growth cones. The STIM1-microtubule-ER interaction provides a new model for spatial localization of calcium signals in navigating growth cones in the nascent nervous system.
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6
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Meade ME, Roginsky JE, Schulz JR. Primary cell culture of adult zebrafish spinal neurons for electrophysiological studies. J Neurosci Methods 2019; 322:50-57. [PMID: 31028770 DOI: 10.1016/j.jneumeth.2019.04.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/21/2019] [Accepted: 04/23/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Zebrafish (Danio rerio) are growing in popularity as a vertebrate model organism for the study of spinal neurocircuitry and locomotion. While many studies have used the zebrafish model system for electrophysiological analyses in embryonic and larval stages, there is a growing interest in studying spinal circuits and neurons from adult fish. NEW METHOD To expand upon the existing toolset available to the zebrafish research community, we have developed the first primary cell culture system of adult zebrafish spinal neurons. The intact spinal cord is dissected, and neurons are isolated through enzymatic digestion and mechanical dissociation. Identifiable neurons are viable for electrophysiological analyses after two days in culture. RESULTS Spinal neurons in culture were confirmed by immunofluorescence labeling and found to exhibit distinct morphologies from other cell types, allowing neurons to be identified based on morphology alone. Neurons were suitable for calcium imaging and whole cell patch clamp recordings, which revealed excitable cells with voltage-gated whole cell currents, including tetrodotoxin-sensitive sodium currents. COMPARISON WITH EXISTING METHODS This primary cell culture system is the only methodology available to isolate neurons from the adult zebrafish spinal cord. Other methods rely on keeping the spinal cord intact or the utilization of embryonic or larval stage fish. This method provides a robust platform for use in neurophysiological and pharmacological studies. CONCLUSIONS The novel primary cell culture system described here provides the first in vitro methodology available to isolate and culture neurons from the adult zebrafish spinal cord for use in electrophysiological analyses.
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Affiliation(s)
- Max E Meade
- Occidental College, Department of Biology, 1600 Campus Road, Los Angeles, California, 90041, United States.
| | - Jessica E Roginsky
- Occidental College, Department of Biology, 1600 Campus Road, Los Angeles, California, 90041, United States.
| | - Joseph R Schulz
- Occidental College, Department of Biology, 1600 Campus Road, Los Angeles, California, 90041, United States.
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7
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Acosta JR, Watchon M, Yuan KC, Fifita JA, Svahn AJ, Don EK, Winnick CG, Blair IP, Nicholson GA, Cole NJ, Goldsbury C, Laird AS. Neuronal cell culture from transgenic zebrafish models of neurodegenerative disease. Biol Open 2018; 7:bio.036475. [PMID: 30190267 PMCID: PMC6215410 DOI: 10.1242/bio.036475] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We describe a protocol for culturing neurons from transgenic zebrafish embryos to investigate the subcellular distribution and protein aggregation status of neurodegenerative disease-causing proteins. The utility of the protocol was demonstrated on cell cultures from zebrafish that transgenically express disease-causing variants of human fused in sarcoma (FUS) and ataxin-3 proteins, in order to study amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia type-3 (SCA3), respectively. A mixture of neuronal subtypes, including motor neurons, exhibited differentiation and neurite outgrowth in the cultures. As reported previously, mutant human FUS was found to be mislocalized from nuclei to the cytosol, mimicking the pathology seen in human ALS and the zebrafish FUS model. In contrast, neurons cultured from zebrafish expressing human ataxin-3 with disease-associated expanded polyQ repeats did not accumulate within nuclei in a manner often reported to occur in SCA3. Despite this, the subcellular localization of the human ataxin-3 protein seen in cell cultures was similar to that found in the SCA3 zebrafish themselves. The finding of similar protein localization and aggregation status in the neuronal cultures and corresponding transgenic zebrafish models confirms that this cell culture model is a useful tool for investigating the cell biology and proteinopathy signatures of mutant proteins for the study of neurodegenerative disease. Summary: This article describes the optimization and validation of a protocol for culturing of neurons from transgenic zebrafish for the study of neurodegenerative diseases.
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Affiliation(s)
- Jamie R Acosta
- The Brain & Mind Centre, University of Sydney, Sydney, New South Wales 2050, Australia.,The Bosch Institute, University of Sydney, Sydney, New South Wales 2006, Australia.,Discipline of Anatomy and Histology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Maxinne Watchon
- Discipline of Anatomy and Histology, University of Sydney, Sydney, New South Wales 2006, Australia.,Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia.,Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Kristy C Yuan
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Jennifer A Fifita
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Adam J Svahn
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Emily K Don
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Claire G Winnick
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Ian P Blair
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Garth A Nicholson
- Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia.,Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia.,ANZAC Research Institute, Concord Repatriation Hospital, Sydney, New South Wales 2139, Australia
| | - Nicholas J Cole
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Claire Goldsbury
- The Brain & Mind Centre, University of Sydney, Sydney, New South Wales 2050, Australia.,The Bosch Institute, University of Sydney, Sydney, New South Wales 2006, Australia.,Discipline of Anatomy and Histology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Angela S Laird
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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8
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Souto S, Olveira JG, Vázquez-Salgado L, Dopazo CP, Bandín I. Betanodavirus infection in primary neuron cultures from sole. Vet Res 2018; 49:86. [PMID: 30185222 PMCID: PMC6125867 DOI: 10.1186/s13567-018-0580-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/04/2018] [Indexed: 01/03/2023] Open
Abstract
Nervous necrosis virus (NNV), G. Betanodavirus, is the causative agent of viral encephalopathy and retinopathy, a disease that causes mass mortalities in a wide range of fish species. Betanodaviruses are neurotropic viruses and their replication in the susceptible fish species seems to be almost entirely restricted to nerve tissue. However, none of the cell lines used for NNV propagation has a nervous origin. In this study, first we established a protocol for the primary culture of neurons from Senegalese sole, which made it possible to further study virus-host cell interactions. Then, we compared the replication of three NNV strains with different genotypes (SJNNV, RGNNV and a RGNNV/SJNNV reassortant strain) in sole neuron primary cultures and E-11 cells. In addition, to study how two amino acid substitutions at the c-terminal of the capsid protein (positions 247 and 270) affect the binding to cell receptors, a recombinant strain was also tested. The results show that sole neural cells enabled replication of all the tested NNV strains. However, the recombinant strain shows a clearly delayed replication when compared with the wt strain. This delay was not observed in virus replicating in E-11 cells, suggesting a viral interaction with different cell receptors. The establishment of a sole primary neuronal culture protocol provides an important tool for research into betanodavirus infection in sole.
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Affiliation(s)
- Sandra Souto
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain.
| | - José G Olveira
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Lucía Vázquez-Salgado
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Carlos P Dopazo
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Isabel Bandín
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
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9
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Kelu JJ, Webb SE, Galione A, Miller AL. TPC2-mediated Ca 2+ signaling is required for the establishment of synchronized activity in developing zebrafish primary motor neurons. Dev Biol 2018; 438:57-68. [PMID: 29577882 DOI: 10.1016/j.ydbio.2018.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 10/17/2022]
Abstract
During the development of the early spinal circuitry in zebrafish, spontaneous Ca2+ transients in the primary motor neurons (PMNs) are reported to transform from being slow and uncorrelated, to being rapid, synchronized and patterned. In this study, we demonstrated that in intact zebrafish, Ca2+ release via two-pore channel type 2 (TPC2) from acidic stores/endolysosomes is required for the establishment of synchronized activity in the PMNs. Using the SAIGFF213A;UAS:GCaMP7a double-transgenic zebrafish line, Ca2+ transients were visualized in the caudal PMNs (CaPs). TPC2 inhibition via molecular, genetic or pharmacological means attenuated the CaP Ca2+ transients, and decreased the normal ipsilateral correlation and contralateral anti-correlation, indicating a disruption in normal spinal circuitry maturation. Furthermore, treatment with MS-222 resulted in a complete (but reversible) inhibition of the CaP Ca2+ transients, as well as a significant decrease in the concentration of the Ca2+ mobilizing messenger, nicotinic acid adenine diphosphate (NAADP) in whole embryo extract. Together, our new data suggest a novel function for NAADP/TPC2-mediated Ca2+ signaling in the development, coordination, and maturation of the spinal network in zebrafish embryos.
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Affiliation(s)
- Jeffrey J Kelu
- Division of Life Science&State Key Laboratory of Molecular Neuroscience, HKUST, Hong Kong
| | - Sarah E Webb
- Division of Life Science&State Key Laboratory of Molecular Neuroscience, HKUST, Hong Kong
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Andrew L Miller
- Division of Life Science&State Key Laboratory of Molecular Neuroscience, HKUST, Hong Kong.
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10
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Kelu JJ, Webb SE, Parrington J, Galione A, Miller AL. Ca 2+ release via two-pore channel type 2 (TPC2) is required for slow muscle cell myofibrillogenesis and myotomal patterning in intact zebrafish embryos. Dev Biol 2017; 425:109-129. [PMID: 28390800 DOI: 10.1016/j.ydbio.2017.03.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/30/2017] [Accepted: 03/31/2017] [Indexed: 01/14/2023]
Abstract
We recently demonstrated a critical role for two-pore channel type 2 (TPC2)-mediated Ca2+ release during the differentiation of slow (skeletal) muscle cells (SMC) in intact zebrafish embryos, via the introduction of a translational-blocking morpholino antisense oligonucleotide (MO). Here, we extend our study and demonstrate that knockdown of TPC2 with a non-overlapping splice-blocking MO, knockout of TPC2 (via the generation of a tpcn2dhkz1a mutant line of zebrafish using CRISPR/Cas9 gene-editing), or the pharmacological inhibition of TPC2 action with bafilomycin A1 or trans-ned-19, also lead to a significant attenuation of SMC differentiation, characterized by a disruption of SMC myofibrillogenesis and gross morphological changes in the trunk musculature. When the morphants were injected with tpcn2-mRNA or were treated with IP3/BM or caffeine (agonists of the inositol 1,4,5-trisphosphate receptor (IP3R) and ryanodine receptor (RyR), respectively), many aspects of myofibrillogenesis and myotomal patterning (and in the case of the pharmacological treatments, the Ca2+ signals generated in the SMCs), were rescued. STED super-resolution microscopy revealed a close physical relationship between clusters of RyR in the terminal cisternae of the sarcoplasmic reticulum (SR), and TPC2 in lysosomes, with a mean estimated separation of ~52-87nm. Our data therefore add to the increasing body of evidence, which indicate that localized Ca2+ release via TPC2 might trigger the generation of more global Ca2+ release from the SR via Ca2+-induced Ca2+ release.
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MESH Headings
- Animals
- Base Sequence
- Behavior, Animal/drug effects
- Body Patterning/drug effects
- CRISPR-Cas Systems/genetics
- Caffeine/pharmacology
- Calcium/metabolism
- Calcium Channels/metabolism
- Calcium Signaling/drug effects
- Cell Death/drug effects
- Cells, Cultured
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Gene Knockdown Techniques
- Gene Knockout Techniques
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Kinesins/metabolism
- Macrolides/pharmacology
- Models, Biological
- Morpholinos/pharmacology
- Motor Activity/drug effects
- Muscle Cells/cytology
- Muscle Cells/drug effects
- Muscle Cells/metabolism
- Muscle Development/drug effects
- Muscle Fibers, Slow-Twitch/cytology
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Phenotype
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Ryanodine Receptor Calcium Release Channel/metabolism
- Sarcomeres/drug effects
- Sarcomeres/metabolism
- Zebrafish/embryology
- Zebrafish/metabolism
- Zebrafish Proteins/metabolism
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Affiliation(s)
- Jeffrey J Kelu
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PR China
| | - Sarah E Webb
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PR China
| | - John Parrington
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Andrew L Miller
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PR China; Marine Biological Laboratory, Woods Hole, MA, USA.
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11
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Kelu JJ, Chan HLH, Webb SE, Cheng AHH, Ruas M, Parrington J, Galione A, Miller AL. Two-Pore Channel 2 activity is required for slow muscle cell-generated Ca(2+) signaling during myogenesis in intact zebrafish. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2016; 59:313-25. [PMID: 26679948 DOI: 10.1387/ijdb.150206am] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We have recently characterized essential inositol 1,4,5-trisphosphate receptor (IP 3R) and ryanodine receptor (RyR)-mediated Ca(2+) signals generated during the differentiation of slow muscle cells (SMCs) in intact zebrafish embryos. Here, we show that the lysosomal two-pore channel 2 (TPC2) also plays a crucial role in generating, and perhaps triggering, these essential Ca(2+) signals, and thus contributes to the regulation of skeletal muscle myogenesis. We used a transgenic line of zebrafish that expresses the bioluminescent Ca(2+) reporter, aequorin, specifically in skeletal muscle, in conjunction with morpholino (MO)-based and pharmacological inhibition of TPC2, in both intact embryos and isolated SMCs. MO-based knock-down of TPC2 resulted in a dramatic attenuation of the Ca(2+) signals, whereas the introduction of TPCN2-MO and TPCN2 mRNA together partially rescued the Ca(2+) signaling signature. Embryos treated with trans-ned-19 or bafilomycin A1, a specific NAADP receptor inhibitor and vacuolar-type H(+)ATPase inhibitor, respectively, also displayed a similar disruption of SMC Ca(2+) signaling. TPC2 and lysosomes were shown via immunohistochemistry and confocal laser scanning microscopy to be localized in perinuclear and striated cytoplasmic domains of SMCs, coincident with patterns of IP 3R and RyR expression. These data together imply that TPC2-mediated Ca(2+) release from lysosomes acts upstream from RyR- and IP 3R-mediated Ca(2+) release, suggesting that the former might act as a sensitive trigger to initiate the SR-mediated Ca(2+)-induced-Ca(2+)-release essential for SMC myogenesis and function.
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Affiliation(s)
- Jeffrey J Kelu
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PRC
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12
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Davey CF, Mathewson AW, Moens CB. PCP Signaling between Migrating Neurons and their Planar-Polarized Neuroepithelial Environment Controls Filopodial Dynamics and Directional Migration. PLoS Genet 2016; 12:e1005934. [PMID: 26990447 PMCID: PMC4798406 DOI: 10.1371/journal.pgen.1005934] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 02/24/2016] [Indexed: 11/18/2022] Open
Abstract
The planar cell polarity (PCP) pathway is a cell-contact mediated mechanism for transmitting polarity information between neighboring cells. PCP “core components” (Vangl, Fz, Pk, Dsh, and Celsr) are essential for a number of cell migratory events including the posterior migration of facial branchiomotor neurons (FBMNs) in the plane of the hindbrain neuroepithelium in zebrafish and mice. While the mechanism by which PCP signaling polarizes static epithelial cells is well understood, how PCP signaling controls highly dynamic processes like neuronal migration remains an important outstanding question given that PCP components have been implicated in a range of directed cell movements, particularly during vertebrate development. Here, by systematically disrupting PCP signaling in a rhombomere-restricted manner we show that PCP signaling is required both within FBMNs and the hindbrain rhombomere 4 environment at the time when they initiate their migration. Correspondingly, we demonstrate planar polarized localization of PCP core components Vangl2 and Fzd3a in the hindbrain neuroepithelium, and transient localization of Vangl2 at the tips of retracting FBMN filopodia. Using high-resolution timelapse imaging of FBMNs in genetic chimeras we uncover opposing cell-autonomous and non-cell-autonomous functions for Fzd3a and Vangl2 in regulating FBMN protrusive activity. Within FBMNs, Fzd3a is required to stabilize filopodia while Vangl2 has an antagonistic, destabilizing role. However, in the migratory environment Fzd3a acts to destabilize FBMN filopodia while Vangl2 has a stabilizing role. Together, our findings suggest a model in which PCP signaling between the planar polarized neuroepithelial environment and FBMNs directs migration by the selective stabilization of FBMN filopodia. Planar cell polarity (PCP) is a common feature of many animal tissues. This type of polarity is most obvious in cells that are organized into epithelial sheets, where PCP signaling components act to orient cells in the plane of the tissue. Although, PCP is best understood for its function in polarizing stable epithelia, PCP is also required for the dynamic process of cell migration in animal development and disease. The goal of this study was to determine how PCP functions to control cell migration. We used the migration of facial branchiomotor neurons in the zebrafish hindbrain, which requires almost the entire suite of PCP core components, to address this question. We present evidence that PCP signaling within migrating neurons, and between migrating neurons and cells of their migratory environment promote migration by regulating filopodial dynamics. Our results suggest that broadly conserved interactions between PCP components control the cytoskeleton in motile cells and non-motile epithelia alike.
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Affiliation(s)
- Crystal F. Davey
- Division of Basic Science, Fred Hutchinson Cancer Research Center, and University of Washington Molecular and Cellular Biology Graduate Program, Seattle, Washington, United States of America
| | - Andrew W. Mathewson
- Division of Basic Science, Fred Hutchinson Cancer Research Center, and University of Washington Molecular and Cellular Biology Graduate Program, Seattle, Washington, United States of America
| | - Cecilia B. Moens
- Division of Basic Science, Fred Hutchinson Cancer Research Center, and University of Washington Molecular and Cellular Biology Graduate Program, Seattle, Washington, United States of America
- * E-mail:
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13
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Wang F, Chen X, Shi W, Yao L, Gao M, Yang Y, Hao A. Zdhhc15b Regulates Differentiation of Diencephalic Dopaminergic Neurons in zebrafish. J Cell Biochem 2015; 116:2980-91. [DOI: 10.1002/jcb.25256] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 06/09/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Fen Wang
- KeyLaboratory of the Ministry of Education; Shandong Provincial Key Laboratory of Mental Department of Histology Embryology; Shandong University School of Medicine; No. 44 Wenhua Xi Road; Jinan Shandong 250012 PR China
| | - Xueran Chen
- Center of Medical Physics and Technology; Hefei Institutes of Physical Science, Chinese Academy of Sciences; No. 350, Shushan Hu Road Hefei AnHui 230031 PR China
| | - Wei Shi
- KeyLaboratory of the Ministry of Education; Shandong Provincial Key Laboratory of Mental Department of Histology Embryology; Shandong University School of Medicine; No. 44 Wenhua Xi Road; Jinan Shandong 250012 PR China
| | - Linli Yao
- KeyLaboratory of the Ministry of Education; Shandong Provincial Key Laboratory of Mental Department of Histology Embryology; Shandong University School of Medicine; No. 44 Wenhua Xi Road; Jinan Shandong 250012 PR China
| | - Ming Gao
- Reproductive medical center of Shandong University; Shandong University School of Medicine; No. 44, Wenhua Xi Road; Jinan Shandong 250012 PR China
| | - Yang Yang
- Infertility Center, Qilu Hospital; Shandong University School of Medicine; No. 44, Wenhua Xi Road; Jinan Shandong 250012 PR China
| | - Aijun Hao
- KeyLaboratory of the Ministry of Education; Shandong Provincial Key Laboratory of Mental Department of Histology Embryology; Shandong University School of Medicine; No. 44 Wenhua Xi Road; Jinan Shandong 250012 PR China
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14
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Welzel G, Seitz D, Schuster S. Magnetic-activated cell sorting (MACS) can be used as a large-scale method for establishing zebrafish neuronal cell cultures. Sci Rep 2015; 5:7959. [PMID: 25609542 PMCID: PMC4302367 DOI: 10.1038/srep07959] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/29/2014] [Indexed: 01/07/2023] Open
Abstract
Neuronal cell cultures offer a crucial tool to mechanistically analyse regeneration in the nervous system. Despite the increasing importance of zebrafish (Danio rerio) as an in vivo model in neurobiological and biomedical research, in vitro approaches to the nervous system are lagging far behind and no method is currently available for establishing enriched neuronal cell cultures. Here we show that magnetic-activated cell sorting (MACS) can be used for the large-scale generation of neuronal-restricted progenitor (NRP) cultures from embryonic zebrafish. Our findings provide a simple and semi-automated method that is likely to boost the use of neuronal cell cultures as a tool for the mechanistic dissection of key processes in neuronal regeneration and development.
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Affiliation(s)
- Georg Welzel
- 1] Department of Animal Physiology, University of Bayreuth, 95440 Bayreuth, Germany [2] Friedrich-Baur BioMed Center, 95448 Bayreuth
| | - Daniel Seitz
- 1] Department of Animal Physiology, University of Bayreuth, 95440 Bayreuth, Germany [2] Friedrich-Baur BioMed Center, 95448 Bayreuth
| | - Stefan Schuster
- 1] Department of Animal Physiology, University of Bayreuth, 95440 Bayreuth, Germany [2] Friedrich-Baur BioMed Center, 95448 Bayreuth
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15
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Chen Z, Lee H, Henle SJ, Cheever TR, Ekker SC, Henley JR. Primary neuron culture for nerve growth and axon guidance studies in zebrafish (Danio rerio). PLoS One 2013; 8:e57539. [PMID: 23469201 PMCID: PMC3587632 DOI: 10.1371/journal.pone.0057539] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/25/2013] [Indexed: 12/21/2022] Open
Abstract
Zebrafish (Danio rerio) is a widely used model organism in genetics and developmental biology research. Genetic screens have proven useful for studying embryonic development of the nervous system in vivo, but in vitro studies utilizing zebrafish have been limited. Here, we introduce a robust zebrafish primary neuron culture system for functional nerve growth and guidance assays. Distinct classes of central nervous system neurons from the spinal cord, hindbrain, forebrain, and retina from wild type zebrafish, and fluorescent motor neurons from transgenic reporter zebrafish lines, were dissociated and plated onto various biological and synthetic substrates to optimize conditions for axon outgrowth. Time-lapse microscopy revealed dynamically moving growth cones at the tips of extending axons. The mean rate of axon extension in vitro was 21.4±1.2 µm hr−1 s.e.m. for spinal cord neurons, which corresponds to the typical ∼0.5 mm day−1 growth rate of nerves in vivo. Fluorescence labeling and confocal microscopy demonstrated that bundled microtubules project along axons to the growth cone central domain, with filamentous actin enriched in the growth cone peripheral domain. Importantly, the growth cone surface membrane expresses receptors for chemotropic factors, as detected by immunofluorescence microscopy. Live-cell functional assays of axon extension and directional guidance demonstrated mammalian brain-derived neurotrophic factor (BDNF)-dependent stimulation of outgrowth and growth cone chemoattraction, whereas mammalian myelin-associated glycoprotein inhibited outgrowth. High-resolution live-cell Ca2+-imaging revealed local elevation of cytoplasmic Ca2+ concentration in the growth cone induced by BDNF application. Moreover, BDNF-induced axon outgrowth, but not basal outgrowth, was blocked by treatments to suppress cytoplasmic Ca2+ signals. Thus, this primary neuron culture model system may be useful for studies of neuronal development, chemotropic axon guidance, and mechanisms underlying inhibition of neural regeneration in vitro, and complement observations made in vivo.
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Affiliation(s)
- Zheyan Chen
- Mayo Graduate School, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Han Lee
- Mayo Graduate School, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Steven J. Henle
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Thomas R. Cheever
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Stephen C. Ekker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - John R. Henley
- Mayo Graduate School, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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16
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Song Y, Wang M, Mao F, Shao M, Zhao B, Song Z, Shao C, Gong Y. Knockdown of Pnpla6 protein results in motor neuron defects in zebrafish. Dis Model Mech 2012; 6:404-13. [PMID: 22996643 PMCID: PMC3597022 DOI: 10.1242/dmm.009688] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mutations in patatin-like phospholipase domain containing 6 (PNPLA6), also known as neuropathy target esterase (NTE) or SPG39, cause hereditary spastic paraplegia (HSP). Although studies on animal models, including mice and Drosophila, have extended our understanding of PNPLA6, its roles in neural development and in HSP are not clearly understood. Here, we describe the generation of a vertebrate model of PNPLA6 insufficiency using morpholino oligonucleotide knockdown in zebrafish (Danio rerio). Pnpla6 knockdown resulted in developmental abnormalities and motor neuron defects, including axon truncation and branching. The phenotypes in pnpla6 knockdown morphants were rescued by the introduction of wild-type, but not mutant, human PNPLA6 mRNA. Our results also revealed the involvement of BMP signaling in pnpla6 knockdown phenotypes. Taken together, these results demonstrate an important role of PNPLA6 in motor neuron development and implicate overexpression of BMP signaling as a possible mechanism underlying the developmental defects in pnpla6 morphants.
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Affiliation(s)
- Yang Song
- Institute of Medical Genetics and Key Laboratory for Experimental Teratology of Ministry of Education, School of Medicine, Shandong University, Jinan 250012 Shandong, China
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17
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Sakowski SA, Lunn JS, Busta AS, Palmer M, Dowling JJ, Feldman EL. A novel approach to study motor neurons from zebrafish embryos and larvae in culture. J Neurosci Methods 2012; 205:277-82. [PMID: 22285259 DOI: 10.1016/j.jneumeth.2012.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 01/11/2012] [Accepted: 01/11/2012] [Indexed: 12/27/2022]
Abstract
Zebrafish are becoming increasingly popular models for examining the mechanisms of and treatments for neurological diseases. The available methods and technology to examine disease processes in vivo are increasing, however, detailed observations of subcellular structures and processes are complex in whole organisms. To address this need, we developed a primary motor neuron (MN) culture technique for utilization with zebrafish neurological disease models. Our protocol enables the culturing of cells from embryos older than 24h post-fertilization, at points after MN axonal development and outgrowth begins, which enables MN axons to develop in vivo in the context of the normal endogenous cues of the model organism, while also providing the accessibility of an in vitro system. When utilized with the increasing number of genetically modified or transgenic models of neurological diseases, this approach provides a novel tool for the examination of cellular and subcellular disease mechanisms, and offers a new platform for therapeutic discoveries in zebrafish.
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18
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Chung AY, Kim MJ, Kim D, Bang S, Hwang SW, Lim CS, Lee S, Park HC, Huh TL. Neuron-specific expression of atp6v0c2 in zebrafish CNS. Dev Dyn 2011; 239:2501-8. [PMID: 20839327 DOI: 10.1002/dvdy.22383] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Vacuolar ATPase (V-ATPase) is a multi-subunit enzyme that plays an important role in the acidification of a variety of intracellular compartments. ATP6V0C is subunit c of the V(0) domain that forms the proteolipid pore of the enzyme. In the present study, we investigated the neuron-specific expression of atp6v0c2, a novel isoform of the V-ATPase c-subunit, during the development of the zebrafish CNS. Zebrafish atp6v0c2 was isolated from a genome-wide analysis of the zebrafish mib(ta52b) mutant designed to identify genes differentially regulated by Notch signaling. Whole-mount in situ hybridization revealed that atp6v0c2 is expressed in a subset of CNS neurons beginning several hours after the emergence of post-mitotic neurons. The ATP6V0C2 protein is co-localized with the presynaptic vesicle marker, SV2, suggesting that it is involved in neurotransmitter storage and/or secretion in neurons. In addition, the loss-of-function experiment suggests that ATP6V0C2 is involved in the control of neuronal excitability.
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Affiliation(s)
- Ah-Young Chung
- School of Life Science and Biotechnology, Kyungpook National University, Daegu, Korea
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19
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Fassier C, Hutt JA, Scholpp S, Lumsden A, Giros B, Nothias F, Schneider-Maunoury S, Houart C, Hazan J. Zebrafish atlastin controls motility and spinal motor axon architecture via inhibition of the BMP pathway. Nat Neurosci 2010; 13:1380-7. [PMID: 20935645 DOI: 10.1038/nn.2662] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 08/26/2010] [Indexed: 01/25/2023]
Abstract
To better understand hereditary spastic paraplegia (HSP), we characterized the function of atlastin, a protein that is frequently involved in juvenile forms of HSP, by analyzing loss- and gain-of-function phenotypes in the developing zebrafish. We found that knockdown of the gene for atlastin (atl1) caused a severe decrease in larval mobility that was preceded by abnormal architecture of spinal motor axons and was associated with a substantial upregulation of the bone morphogenetic protein (BMP) signaling pathway. Overexpression analyses confirmed that atlastin inhibits BMP signaling. In primary cultures of zebrafish spinal neurons, Atlastin partially colocalized with type I BMP receptors in late endosomes distributed along neurites, which suggests that atlastin may regulate BMP receptor trafficking. Finally, genetic or pharmacological inhibition of BMP signaling was sufficient to rescue the loss of mobility and spinal motor axon defects of atl1 morphants, emphasizing the importance of fine-tuning the balance of BMP signaling for vertebrate motor axon architecture and stability.
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Affiliation(s)
- Coralie Fassier
- CNRS UMR 7224, Physiopathologie des Maladies du Système Nerveux Central, Paris, France
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20
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Nakano Y, Fujita M, Ogino K, Saint-Amant L, Kinoshita T, Oda Y, Hirata H. Biogenesis of GPI-anchored proteins is essential for surface expression of sodium channels in zebrafish Rohon-Beard neurons to respond to mechanosensory stimulation. Development 2010; 137:1689-98. [PMID: 20392743 DOI: 10.1242/dev.047464] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In zebrafish, Rohon-Beard (RB) neurons are primary sensory neurons present during the embryonic and early larval stages. At 2 days post-fertilization (dpf), wild-type zebrafish embryos respond to mechanosensory stimulation and swim away from the stimuli, whereas mi310 mutants are insensitive to touch. During approximately 2-4 dpf, wild-type RB neurons undergo programmed cell death, which is caused by sodium current-mediated electrical activity, whereas mutant RB cells survive past 4 dpf, suggesting a defect of sodium currents in the mutants. Indeed, electrophysiological recordings demonstrated the generation of action potentials in wild-type RB neurons, whereas mutant RB cells failed to fire owing to the reduction of voltage-gated sodium currents. Labeling of dissociated RB neurons with an antibody against voltage-gated sodium channels revealed that sodium channels are expressed at the cell surface in wild-type, but not mutant, RB neurons. Finally, in mi310 mutants, we identified a mis-sense mutation in pigu, a subunit of GPI (glycosylphosphatidylinositol) transamidase, which is essential for membrane anchoring of GPI-anchored proteins. Taken together, biogenesis of GPI-anchored proteins is necessary for cell surface expression of sodium channels and thus for firings of RB neurons, which enable zebrafish embryos to respond to mechanosensory stimulation.
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Affiliation(s)
- Yuri Nakano
- Graduate School of Science, Nagoya University, Nagoya, Japan
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21
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Latefi NS, Pedraza L, Schohl A, Li Z, Ruthazer ES. N-cadherin prodomain cleavage regulates synapse formation in vivo. Dev Neurobiol 2009; 69:518-29. [PMID: 19365814 DOI: 10.1002/dneu.20718] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cadherins are initially synthesized bearing a prodomain that is thought to limit adhesion during early stages of biosynthesis. Functional cadherins lack this prodomain, raising the intriguing possibility that cells may utilize prodomain cleavage as a means to temporally or spatially regulate adhesion after delivery of cadherin to the cell surface. In support of this idea, immunostaining for the prodomain of zebrafish N-cadherin revealed enriched labeling at neuronal surfaces at the soma and along axonal processes. To determine whether post-translational cleavage of the prodomain affects synapse formation, we imaged Rohon-Beard cells in zebrafish embryos expressing GFP-tagged wild-type N-cadherin (NCAD-GFP) or a GFP-tagged N-cadherin mutant expressing an uncleavable prodomain (PRON-GFP) rendering it nonadhesive. NCAD-GFP accumulated at synaptic microdomains in a developmentally regulated manner, and its overexpression transiently accelerated synapse formation. PRON-GFP was much more diffusely distributed along the axon and its overexpression delayed synapse formation. Our results support the notion that N-cadherin serves to stabilize pre- to postsynaptic contacts early in synapse development and suggests that regulated cleavage of the N-cadherin prodomain may be a mechanism by which the kinetics of synaptogenesis are regulated.
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Affiliation(s)
- Nazlie S Latefi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4
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22
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Abe H, Oka Y. Primary culture of the isolated terminal nerve-gonadotrophin-releasing hormone neurones derived from adult teleost (dwarf gourami, Colisa lalia) brain for the study of peptide release mechanisms. J Neuroendocrinol 2009; 21:489-505. [PMID: 19302187 DOI: 10.1111/j.1365-2826.2009.01866.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Terminal nerve (TN)-gonadotrophin-releasing hormone (GnRH) neurones are suggested to release GnRH peptides from widely-branched neural processes and the somatodendritic regions, depending on their firing activities. The released GnRH may exert its neuromodulatory actions on GnRH receptors located on various target neurones. The electrophysiological and morphological characteristics of TN-GnRH neurones, which are shared with other peptidergic neurones of vertebrate brains, are thought to represent general features of neuromodulatory and ⁄ or neurosecretory neurones. To address questions concerning the ways in which the electrical activities of peptidergic (TN-GnRH) neuronal somata affect GnRH release from different neuronal compartments, we established a primary culture system of TN-GnRH neurones, which will facilitate simultaneous recordings of various physiological signals from different compartments of a single TN-GnRH neurone cultured in a flat plane. The whole brain of an adult freshwater teleost, the dwarf gourami, was dissected out. The TN-GnRH neurones were then isolated and plated on a coverslip in culture medium. The isolated TN-GnRH neurones could be cultured for up to 2 weeks. In culture, the neurones grew both axon- and dendrite-like neurites, and these processes were phenotypically similar to those found in situ. Unlike the neurones in situ, the cultured neurones had somewhat depolarised resting membrane potentials and showed no spontaneous discharge, which, however, should not be considered to comprise unhealthy culture conditions. Instead, they showed subthreshold spontaneous membrane potential oscillations and could be induced to fire in phasic or tonic patterns. In addition, stimulus-induced exocytotic events could be demonstrated in the soma and neurites using a fluorescent dye, FM1-43. Thus, the present isolated culture of TN-GnRH neurones will open up a wide range of possibilities for studying cellular mechanism of exocytosis, generation of spontaneous firing activity, and neurite outgrowth in peptidergic neurones.
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Affiliation(s)
- Hideki Abe
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Japan.
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23
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Fan X, Majumder A, Reagin SS, Porter EL, Sornborger AT, Keith CH, Lauderdale JD. New statistical methods enhance imaging of cameleon fluorescence resonance energy transfer in cultured zebrafish spinal neurons. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:034017. [PMID: 17614725 DOI: 10.1117/1.2745263] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Cameleons are genetically encoded fluorescence resonance energy transfer (FRET)-based Ca(2+) indicators. Attempts to use cameleons to detect neural activity in vertebrate systems have been largely frustrated by the small FRET signal, in contradistinction to the higher signals seen in Drosophila and Caenorhabditis elegans. We have developed a statistical optimization method capable of detecting small ratiometric signals in noisy imaging data, called statistical optimization for the analysis of ratiometric signals. Using this method, we can detect and estimate anticorrelated ratiometric signals with subcellular resolution in cultured, dissociated zebrafish spinal neurons expressing cameleon or loaded with fluo-4 and fura-red. This method may make it possible to use yellow cameleons for measuring neural activity at high resolution in transgenic animals.
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Affiliation(s)
- Xiang Fan
- The University of Georgia, Department of Cellular Biology, Athens, Georgia 30602, USA
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24
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Duarte AS, Rosa N, Duarte EP, Pires E, Barros MT. Cardosins: A new and efficient plant enzymatic tool to dissociate neuronal cells for the establishment of cell cultures. Biotechnol Bioeng 2006; 97:991-6. [PMID: 17099909 DOI: 10.1002/bit.21259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the present work, we examined the feasibility of using cardosins, plant aspartic-proteinases from Cynara cardunculus L., to isolate cells from rat embryonic brain. Using morphological and functional assays, we compared cell cultures obtained with cardosins with those prepared with a well-established trypsin protocol. Cardosins and trypsin dissociation produced cells with similar yield, viability, and GABA release in response to a depolarizing stimulus. However, cardosins-dissociated cells appeared to recover faster in culture, as assessed by the MTT-test and by the number and length of neurtites, suggesting that cardosins are less aggressive to neurons than trypsin. This feature might be helpful for research and medical purposes requiring fast manipulations of cells.
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Affiliation(s)
- A S Duarte
- CESAM and Departamento de Biologia, Universidade de Aveiro, Aveiro, Portugal
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25
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Cormie P, Robinson KR. Embryonic zebrafish neuronal growth is not affected by an applied electric field in vitro. Neurosci Lett 2006; 411:128-32. [PMID: 17084971 PMCID: PMC1847632 DOI: 10.1016/j.neulet.2006.10.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 10/13/2006] [Accepted: 10/17/2006] [Indexed: 11/21/2022]
Abstract
Naturally occurring electric fields (EFs) have been implicated in cell guidance during embryonic development and adult wound healing. Embryonic Xenopus laevis neurons sprout preferentially towards the cathode, turn towards the cathode, and migrate faster towards the cathode in the presence of an external EF in vitro. A recent Phase 1 clinical trial has investigated the effects of oscillating EFs on human spinal cord regeneration. The purpose of this study was to investigate whether embryonic zebrafish neurons respond to an applied EF, and thus extend this research into another vertebrate system. Neural tubes of zebrafish embryos (16-17 somites) were dissected and dissociated neuroblasts were plated onto laminin-coated glass. A 100 mV/mm EF was applied to cell cultures for 4 or 20 h and the responses of neurons to the applied EFs were investigated. After 4h in an EF neurites were significantly shorter than control neurites. No other statistically significant effects were observed. After 20 h, control and EF-exposed neurites were no different in length. No length difference was seen between cathodally- and anodally-sprouted neurites. Application of an EF did not affect the average number of neurons in a chamber. Growth cones did not migrate preferentially towards either pole of the EF and no asymmetry was seen in neurite sprout sites. We conclude that zebrafish neurons do not respond to a 100 mV/mm applied EF in vitro. This suggests that neurons of other vertebrate species may not respond to applied EFs in the same ways as Xenopus laevis neurons.
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Affiliation(s)
- Peter Cormie
- Purdue University, Department of Biological Sciences, 915 West State Street, West Lafayette, IN 47907, USA.
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