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Meserve JH, Navarro MF, Ortiz EA, Granato M. Celsr3 drives development and connectivity of the acoustic startle hindbrain circuit. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.07.583806. [PMID: 38496637 PMCID: PMC10942420 DOI: 10.1101/2024.03.07.583806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
In the developing brain, groups of neurons organize into functional circuits that direct diverse behaviors. One such behavior is the evolutionarily conserved acoustic startle response, which in zebrafish is mediated by a well-defined hindbrain circuit. While numerous molecular pathways that guide neurons to their synaptic partners have been identified, it is unclear if and to what extent distinct neuron populations in the startle circuit utilize shared molecular pathways to ensure coordinated development. Here, we show that the planar cell polarity (PCP)-associated atypical cadherins Celsr3 and Celsr2, as well as the Celsr binding partner Frizzled 3a/Fzd3a, are critical for axon guidance of two neuron types that form synapses with each other: the command-like neuron Mauthner cells that drive the acoustic startle escape response, and spiral fiber neurons which provide excitatory input to Mauthner cells. We find that Mauthner axon growth towards synaptic targets is vital for Mauthner survival. We also demonstrate that symmetric spiral fiber input to Mauthner cells is critical for escape direction, which is necessary to respond to directional threats. Moreover, we identify distinct roles for Celsr3 and Celsr2, as Celsr3 is required for startle circuit development while Celsr2 is dispensable, though Celsr2 can partially compensate for loss of Celsr3 in Mauthner cells. This contrasts with facial branchiomotor neuron migration in the hindbrain, which requires Celsr2 while we find that Celsr3 is dispensable. Combined, our data uncover critical and distinct roles for individual PCP components during assembly of the acoustic startle hindbrain circuit.
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Affiliation(s)
- Joy H Meserve
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Maria F Navarro
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Elelbin A Ortiz
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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2
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Brown-Panton CA, Sabour S, Zoidl GSO, Zoidl C, Tabatabaei N, Zoidl GR. Gap junction Delta-2b ( gjd2b/Cx35.1) depletion causes hyperopia and visual-motor deficiencies in the zebrafish. Front Cell Dev Biol 2023; 11:1150273. [PMID: 36936688 PMCID: PMC10017553 DOI: 10.3389/fcell.2023.1150273] [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: 01/23/2023] [Accepted: 02/15/2023] [Indexed: 03/06/2023] Open
Abstract
The zebrafish is a powerful model to investigate the developmental roles of electrical synapses because many signaling pathways that regulate the development of the nervous system are highly conserved from fish to humans. Here, we provide evidence linking the mammalian connexin-36 (Cx36) ortholog gjd2b/Cx35.1, a major component of electrical synapses in the zebrafish, with a refractive error in the context of morphological, molecular, and behavioral changes of zebrafish larvae. Two abnormalities were identified. The optical coherence tomography analysis of the adult retina confirmed changes to the refractive properties caused by eye axial length reduction, leading to hyperopic shifts. The gjd2b/Cx35.1 depletion was also correlated with morphological changes to the head and body ratios in larvae. The differential expression of Wnt/ß-catenin signaling genes, connexins, and dopamine receptors suggested a contribution to the observed phenotypic differences. The alteration of visual-motor behavioral responses to abrupt light transitions was aggravated in larvae, providing evidence that cone photoreceptor cell activity was enhanced when gjd2b/Cx35.1 was depleted. The visual disturbances were reversed under low light conditions in gjd2b -/- /Cx35.1-/- larvae. Since qRT-PCR data demonstrated that two rhodopsin genes were downregulated, we speculated that rod photoreceptor cells in gjd2b/Cx35.1-/- larvae were less sensitive to bright light transitions, thus providing additional evidence that a cone-mediated process caused the VMR light-ON hyperactivity after losing Cx35.1 expression. Together, this study provides evidence for the role of gjd2b/Cx35.1 in the development of the visual system and visually guided behaviors.
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Affiliation(s)
- Cherie A. Brown-Panton
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
- *Correspondence: Cherie A. Brown-Panton, ; Georg R. Zoidl,
| | - Shiva Sabour
- Department of Mechanical Engineering, York University, Toronto, ON, Canada
| | - Georg S. O. Zoidl
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
| | - Christiane Zoidl
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
| | - Nima Tabatabaei
- Center for Vision Research, York University, Toronto, ON, Canada
- Department of Mechanical Engineering, York University, Toronto, ON, Canada
| | - Georg R. Zoidl
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
- Department of Psychology, York University, Toronto, ON, Canada
- *Correspondence: Cherie A. Brown-Panton, ; Georg R. Zoidl,
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3
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Sitaraman S, Yadav G, Agarwal V, Jabeen S, Verma S, Jadhav M, Thirumalai V. Gjd2b-mediated gap junctions promote glutamatergic synapse formation and dendritic elaboration in Purkinje neurons. eLife 2021; 10:68124. [PMID: 34346310 PMCID: PMC8382294 DOI: 10.7554/elife.68124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 08/03/2021] [Indexed: 11/13/2022] Open
Abstract
Gap junctions between neurons serve as electrical synapses, in addition to conducting metabolites and signaling molecules. During development, early-appearing gap junctions are thought to prefigure chemical synapses, which appear much later. We present evidence for this idea at a central, glutamatergic synapse and provide some mechanistic insights. Loss or reduction in the levels of the gap junction protein Gjd2b decreased the frequency of glutamatergic miniature excitatory postsynaptic currents (mEPSCs) in cerebellar Purkinje neurons (PNs) in larval zebrafish. Ultrastructural analysis in the molecular layer showed decreased synapse density. Further, mEPSCs had faster kinetics and larger amplitudes in mutant PNs, consistent with their stunted dendritic arbors. Time-lapse microscopy in wild-type and mutant PNs reveals that Gjd2b puncta promote the elongation of branches and that CaMKII may be a critical mediator of this process. These results demonstrate that Gjd2b-mediated gap junctions regulate glutamatergic synapse formation and dendritic elaboration in PNs.
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Affiliation(s)
- Sahana Sitaraman
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Gnaneshwar Yadav
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Vandana Agarwal
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shaista Jabeen
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shivangi Verma
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Meha Jadhav
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Vatsala Thirumalai
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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4
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Shan L, Zhang T, Fan K, Cai W, Liu H. Astrocyte-Neuron Signaling in Synaptogenesis. Front Cell Dev Biol 2021; 9:680301. [PMID: 34277621 PMCID: PMC8284252 DOI: 10.3389/fcell.2021.680301] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 06/14/2021] [Indexed: 01/10/2023] Open
Abstract
Astrocytes are the key component of the central nervous system (CNS), serving as pivotal regulators of neuronal synapse formation and maturation through their ability to dynamically and bidirectionally communicate with synapses throughout life. In the past 20 years, numerous astrocyte-derived molecules promoting synaptogenesis have been discovered. However, our understanding of the cell biological basis underlying intra-neuron processes and astrocyte-mediated synaptogenesis is still in its infancy. Here, we provide a comprehensive overview of the various ways astrocytes talk to neurons, and highlight astrocytes’ heterogeneity that allow them to displays regional-specific capabilities in boosting synaptogenesis. Finally, we conclude with promises and future directions on how organoids generated from human induced pluripotent stem cells (hiPSCs) effectively address the signaling pathways astrocytes employ in synaptic development.
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Affiliation(s)
- Lili Shan
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Tongran Zhang
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Kevin Fan
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Weibo Cai
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Huisheng Liu
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
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5
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Zoidl GR, Spray DC. The Roles of Calmodulin and CaMKII in Cx36 Plasticity. Int J Mol Sci 2021; 22:4473. [PMID: 33922931 PMCID: PMC8123330 DOI: 10.3390/ijms22094473] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 01/07/2023] Open
Abstract
Anatomical and electrophysiological evidence that gap junctions and electrical coupling occur between neurons was initially confined to invertebrates and nonmammals and was thought to be a primitive form of synaptic transmission. More recent studies revealed that electrical communication is common in the mammalian central nervous system (CNS), often coexisting with chemical synaptic transmission. The subsequent progress indicated that electrical synapses formed by the gap junction protein connexin-36 (Cx36) and its paralogs in nonmammals constitute vital elements in mammalian and fish synaptic circuitry. They govern the collective activity of ensembles of coupled neurons, and Cx36 gap junctions endow them with enormous adaptive plasticity, like that seen at chemical synapses. Moreover, they orchestrate the synchronized neuronal network activity and rhythmic oscillations that underlie the fundamental integrative processes, such as memory and learning. Here, we review the available mechanistic evidence and models that argue for the essential roles of calcium, calmodulin, and the Ca2+/calmodulin-dependent protein kinase II in integrating calcium signals to modulate the strength of electrical synapses through interactions with the gap junction protein Cx36.
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Affiliation(s)
- Georg R. Zoidl
- Department of Biology & Center for Vision Research (CVR), York University, Toronto, ON M3J 1P3, Canada
| | - David C. Spray
- Dominick P. Purpura Department of Neuroscience & Department of Medicine (Cardiology), Albert Einstein College of Medicine, New York, NY 10461, USA;
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6
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Emfinger CH, Lőrincz R, Wang Y, York NW, Singareddy SS, Ikle JM, Tryon RC, McClenaghan C, Shyr ZA, Huang Y, Reissaus CA, Meyer D, Piston DW, Hyrc K, Remedi MS, Nichols CG. Beta-cell excitability and excitability-driven diabetes in adult Zebrafish islets. Physiol Rep 2019; 7:e14101. [PMID: 31161721 PMCID: PMC6546968 DOI: 10.14814/phy2.14101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 12/15/2022] Open
Abstract
Islet β-cell membrane excitability is a well-established regulator of mammalian insulin secretion, and defects in β-cell excitability are linked to multiple forms of diabetes. Evolutionary conservation of islet excitability in lower organisms is largely unexplored. Here we show that adult zebrafish islet calcium levels rise in response to elevated extracellular [glucose], with similar concentration-response relationship to mammalian β-cells. However, zebrafish islet calcium transients are nor well coupled, with a shallower glucose-dependence of cytoplasmic calcium concentration. We have also generated transgenic zebrafish that conditionally express gain-of-function mutations in ATP-sensitive K+ channels (KATP -GOF) in β-cells. Following induction, these fish become profoundly diabetic, paralleling features of mammalian diabetes resulting from equivalent mutations. KATP -GOF fish become severely hyperglycemic, with slowed growth, and their islets lose glucose-induced calcium responses. These results indicate that, although lacking tight cell-cell coupling of intracellular Ca2+ , adult zebrafish islets recapitulate similar excitability-driven β-cell glucose responsiveness to those in mammals, and exhibit profound susceptibility to diabetes as a result of inexcitability. While illustrating evolutionary conservation of islet excitability in lower vertebrates, these results also provide important validation of zebrafish as a suitable animal model in which to identify modulators of islet excitability and diabetes.
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Affiliation(s)
- Christopher H. Emfinger
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Department of MedicineDivision of Endocrinology, Metabolism, and Lipid ResearchWashington University in St. Louis School of MedicineSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Réka Lőrincz
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
- Institute of Molecular Biology/CMBILeopold‐Franzens‐University InnsbruckInnsbruckAustria
| | - Yixi Wang
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Nathaniel W. York
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Soma S. Singareddy
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Jennifer M. Ikle
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
- Department of PediatricsWashington University in St. Louis School of MedicineSt. LouisMissouri
- Present address:
Department of CardiologyRenmin Hospital of Wuhan UniversityWuhanChina
| | - Robert C. Tryon
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Conor McClenaghan
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Zeenat A. Shyr
- Department of MedicineDivision of Endocrinology, Metabolism, and Lipid ResearchWashington University in St. Louis School of MedicineSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Yan Huang
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
- Department of PediatricsWashington University in St. Louis School of MedicineSt. LouisMissouri
- Present address:
Department of CardiologyRenmin Hospital of Wuhan UniversityWuhanChina
| | - Christopher A. Reissaus
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
| | - Dirk Meyer
- Institute of Molecular Biology/CMBILeopold‐Franzens‐University InnsbruckInnsbruckAustria
| | - David W. Piston
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Krzysztof Hyrc
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Maria S. Remedi
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Department of MedicineDivision of Endocrinology, Metabolism, and Lipid ResearchWashington University in St. Louis School of MedicineSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
| | - Colin G. Nichols
- Department of Cell Biology and PhysiologyWashington University in St. LouisSt. LouisMissouri
- Center for the Investigation of Membrane Excitability DiseasesWashington University in St. Louis School of MedicineSt. LouisMissouri
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7
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Jabeen S, Thirumalai V. The interplay between electrical and chemical synaptogenesis. J Neurophysiol 2018; 120:1914-1922. [PMID: 30067121 PMCID: PMC6230774 DOI: 10.1152/jn.00398.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neurons communicate with each other via electrical or chemical synaptic connections. The pattern and strength of connections between neurons are critical for generating appropriate output. What mechanisms govern the formation of electrical and/or chemical synapses between two neurons? Recent studies indicate that common molecular players could regulate the formation of both of these classes of synapses. In addition, electrical and chemical synapses can mutually coregulate each other’s formation. Electrical activity, generated spontaneously by the nervous system or initiated from sensory experience, plays an important role in this process, leading to the selection of appropriate connections and the elimination of inappropriate ones. In this review, we discuss recent studies that shed light on the formation and developmental interactions of chemical and electrical synapses.
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Affiliation(s)
- Shaista Jabeen
- National Centre for Biological Sciences, Tata Institute for Fundamental Research , Bangalore , India.,Manipal Academy of Higher Education, Madhav Nagar, Manipal , India
| | - Vatsala Thirumalai
- National Centre for Biological Sciences, Tata Institute for Fundamental Research , Bangalore , India
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8
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Jain RA, Wolman MA, Marsden KC, Nelson JC, Shoenhard H, Echeverry FA, Szi C, Bell H, Skinner J, Cobbs EN, Sawada K, Zamora AD, Pereda AE, Granato M. A Forward Genetic Screen in Zebrafish Identifies the G-Protein-Coupled Receptor CaSR as a Modulator of Sensorimotor Decision Making. Curr Biol 2018; 28:1357-1369.e5. [PMID: 29681477 DOI: 10.1016/j.cub.2018.03.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 01/24/2018] [Accepted: 03/13/2018] [Indexed: 12/26/2022]
Abstract
Animals continuously integrate sensory information and select contextually appropriate responses. Here, we show that zebrafish larvae select a behavioral response to acoustic stimuli from a pre-existing choice repertoire in a context-dependent manner. We demonstrate that this sensorimotor choice is modulated by stimulus quality and history, as well as by neuromodulatory systems-all hallmarks of more complex decision making. Moreover, from a genetic screen coupled with whole-genome sequencing, we identified eight mutants with deficits in this sensorimotor choice, including mutants of the vertebrate-specific G-protein-coupled extracellular calcium-sensing receptor (CaSR), whose function in the nervous system is not well understood. We demonstrate that CaSR promotes sensorimotor decision making acutely through Gαi/o and Gαq/11 signaling, modulated by clathrin-mediated endocytosis. Combined, our results identify the first set of genes critical for behavioral choice modulation in a vertebrate and reveal an unexpected critical role for CaSR in sensorimotor decision making.
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Affiliation(s)
- Roshan A Jain
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biology, Haverford College, Haverford, PA 19041, USA.
| | - Marc A Wolman
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kurt C Marsden
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jessica C Nelson
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hannah Shoenhard
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Fabio A Echeverry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Rose F. Kennedy Center, 1410 Pelham Parkway South, Bronx, NY 10461, USA
| | - Christina Szi
- Department of Biology, Haverford College, Haverford, PA 19041, USA
| | - Hannah Bell
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Julianne Skinner
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emilia N Cobbs
- Department of Biology, Haverford College, Haverford, PA 19041, USA
| | - Keisuke Sawada
- Department of Biology, Haverford College, Haverford, PA 19041, USA
| | - Amy D Zamora
- Department of Biology, Haverford College, Haverford, PA 19041, USA
| | - Alberto E Pereda
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Rose F. Kennedy Center, 1410 Pelham Parkway South, Bronx, NY 10461, USA
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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9
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Sarasamma S, Varikkodan MM, Liang ST, Lin YC, Wang WP, Hsiao CD. Zebrafish: A Premier Vertebrate Model for Biomedical Research in Indian Scenario. Zebrafish 2017; 14:589-605. [PMID: 29023224 DOI: 10.1089/zeb.2017.1447] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The zebrafish (Danio rerio) is a versatile model organism that has been used in biomedical research for several decades to study a wide range of biological phenomena. There are many technical advantages of using zebrafish over other vertebrate models. They are readily available, hardy, easy, and inexpensive to maintain in the laboratory, have a short life cycle, and have excellent fecundity. Due to its optical clarity and reproducible capabilities, it has become one of the predominant models of human genetic diseases. Zebrafish research has made rapid strides in the United States and Europe, but in India the field is at an early stage and many researchers still remain unaware of the full research potential of this tiny fish. The zebrafish model system was introduced into India in the early 2000s. Up to now, more than 200 scientific referred articles have been published by Indian researchers. This review gives an overview of the current state of knowledge for zebrafish research in India, with the aim of promoting wider utilization of zebrafish for high level biological studies.
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Affiliation(s)
- Sreeja Sarasamma
- 1 Department of Chemistry, Chung Yuan Christian University , Chung-Li, Taiwan .,2 Department of Bioscience Technology, Chung Yuan Christian University , Chung-Li, Taiwan .,3 Department of Chemical Biology, Rajiv Gandhi Centre for Biotechnology , Thiruvananthapuram, Kerala, India
| | - Muhammed Muhsin Varikkodan
- 1 Department of Chemistry, Chung Yuan Christian University , Chung-Li, Taiwan .,2 Department of Bioscience Technology, Chung Yuan Christian University , Chung-Li, Taiwan .,4 Department of Biotechnology and Genetic Engineering, Bharathidasan University , Tiruchirapalli, India
| | - Sung-Tzu Liang
- 1 Department of Chemistry, Chung Yuan Christian University , Chung-Li, Taiwan
| | - Yen-Chang Lin
- 5 Graduate Institute of Biotechnology, Chinese Culture University , Taipei, Taiwan
| | - Wen-Pin Wang
- 6 Institute of Medical Sciences, Tzu-Chi University , Hualien, Taiwan .,7 Department of Molecular Biology and Human Genetics, Tzu-Chi University , Hualien, Taiwan
| | - Chung-Der Hsiao
- 1 Department of Chemistry, Chung Yuan Christian University , Chung-Li, Taiwan .,8 Center for Biomedical Technology, Chung Yuan Christian University , Chung-Li, Taiwan .,9 Center for Nanotechnology, Chung Yuan Christian University , Chung-Li, Taiwan
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10
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Vishwanathan A, Daie K, Ramirez AD, Lichtman JW, Aksay ERF, Seung HS. Electron Microscopic Reconstruction of Functionally Identified Cells in a Neural Integrator. Curr Biol 2017; 27:2137-2147.e3. [PMID: 28712570 DOI: 10.1016/j.cub.2017.06.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/02/2017] [Accepted: 06/09/2017] [Indexed: 11/27/2022]
Abstract
Neural integrators are involved in a variety of sensorimotor and cognitive behaviors. The oculomotor system contains a simple example, a hindbrain neural circuit that takes velocity signals as inputs and temporally integrates them to control eye position. Here we investigated the structural underpinnings of temporal integration in the larval zebrafish by first identifying integrator neurons using two-photon calcium imaging and then reconstructing the same neurons through serial electron microscopic analysis. Integrator neurons were identified as those neurons with activities highly correlated with eye position during spontaneous eye movements. Three morphological classes of neurons were observed: ipsilaterally projecting neurons located medially, contralaterally projecting neurons located more laterally, and a population at the extreme lateral edge of the hindbrain for which we were not able to identify axons. Based on their somatic locations, we inferred that neurons with only ipsilaterally projecting axons are glutamatergic, whereas neurons with only contralaterally projecting axons are largely GABAergic. Dendritic and synaptic organization of the ipsilaterally projecting neurons suggests a broad sampling from inputs on the ipsilateral side. We also observed the first conclusive evidence of synapses between integrator neurons, which have long been hypothesized by recurrent network models of integration via positive feedback.
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Affiliation(s)
| | - Kayvon Daie
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10021, USA
| | - Alexandro D Ramirez
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10021, USA
| | - Jeff W Lichtman
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Emre R F Aksay
- Institute for Computational Biomedicine and Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10021, USA
| | - H Sebastian Seung
- Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Computer Science Department, Princeton University, Princeton, NJ 08544, USA.
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11
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The Severity of Acute Stress Is Represented by Increased Synchronous Activity and Recruitment of Hypothalamic CRH Neurons. J Neurosci 2016; 36:3350-62. [PMID: 26985042 DOI: 10.1523/jneurosci.3390-15.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The hypothalamo-pituitary-adrenocortical (HPA) axis regulates stress physiology and behavior. To achieve an optimally tuned adaptive response, it is critical that the magnitude of the stress response matches the severity of the threat. Corticotropin-releasing hormone (CRH) released from the paraventricular nucleus of the hypothalamus is a major regulator of the HPA axis. However, how CRH-producing neurons in an intact animal respond to different stressor intensities is currently not known. Using two-photon calcium imaging on intact larval zebrafish, we recorded the activity of CRH cells, while the larvae were exposed to stressors of varying intensity. By combining behavioral and physiological measures, we first determined how sudden alterations in environmental conditions lead to different levels of stress axis activation. Then, we measured changes in the frequency and amplitude of Ca(2+) transients in individual CRH neurons in response to such stressors. The response magnitude of individual CRH cells covaried with stressor intensity. Furthermore, stressors caused the recruitment of previously inactive CRH neurons in an intensity-dependent manner, thus increasing the pool of responsive CRH cells. Strikingly, stressor-induced activity appeared highly synchronized among CRH neurons, and also across hemispheres. Thus, the stressor strength-dependent output of CRH neurons emerges by a dual mechanism that involves both the increased activity of individual cells and the recruitment of a larger pool of responsive cells. The synchronicity of CRH neurons within and across hemispheres ensures that the overall output of the HPA axis matches the severity of the threat. SIGNIFICANCE STATEMENT Stressors trigger adaptive responses in the body that are essential for survival. How the brain responds to acute stressors of varying intensity in an intact animal, however, is not well understood. We address this question using two-photon Ca(2+) imaging in larval zebrafish with transgenically labeled corticotropin-releasing hormone (CRH) cells, which represent a major regulator of the stress axis. We show that stressor strength-dependent responses of CRH neurons emerge via an intensity-dependent increase in the activity of individual CRH cells, and by an increase in the pool of responsive CRH cells at the population level. Furthermore, we report striking synchronicity among CRH neurons even across hemispheres, which suggests tight intrahypothalamic and interhypothalamic coordination. Thus, our work reveals how CRH neurons respond to different levels of acute stress in vivo.
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Liu Z, Ciarleglio CM, Hamodi AS, Aizenman CD, Pratt KG. A population of gap junction-coupled neurons drives recurrent network activity in a developing visual circuit. J Neurophysiol 2016; 115:1477-86. [PMID: 26763780 DOI: 10.1152/jn.01046.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/08/2016] [Indexed: 01/04/2023] Open
Abstract
In many regions of the vertebrate brain, microcircuits generate local recurrent activity that aids in the processing and encoding of incoming afferent inputs. Local recurrent activity can amplify, filter, and temporally and spatially parse out incoming input. Determining how these microcircuits function is of great interest because it provides glimpses into fundamental processes underlying brain computation. Within the Xenopus tadpole optic tectum, deep layer neurons display robust recurrent activity. Although the development and plasticity of this local recurrent activity has been well described, the underlying microcircuitry is not well understood. Here, using a whole brain preparation that allows for whole cell recording from neurons of the superficial tectal layers, we identified a physiologically distinct population of excitatory neurons that are gap junctionally coupled and through this coupling gate local recurrent network activity. Our findings provide a novel role for neuronal coupling among excitatory interneurons in the temporal processing of visual stimuli.
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Affiliation(s)
- Zhenyu Liu
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming; and
| | | | - Ali S Hamodi
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming; and
| | - Carlos D Aizenman
- Department of Neuroscience, Brown University, Providence, Rhode Island
| | - Kara G Pratt
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming; and
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Modelling the Effects of Electrical Coupling between Unmyelinated Axons of Brainstem Neurons Controlling Rhythmic Activity. PLoS Comput Biol 2015; 11:e1004240. [PMID: 25954930 PMCID: PMC4425518 DOI: 10.1371/journal.pcbi.1004240] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/15/2015] [Indexed: 11/19/2022] Open
Abstract
Gap junctions between fine unmyelinated axons can electrically couple groups of brain neurons to synchronise firing and contribute to rhythmic activity. To explore the distribution and significance of electrical coupling, we modelled a well analysed, small population of brainstem neurons which drive swimming in young frog tadpoles. A passive network of 30 multicompartmental neurons with unmyelinated axons was used to infer that: axon-axon gap junctions close to the soma gave the best match to experimentally measured coupling coefficients; axon diameter had a strong influence on coupling; most neurons were coupled indirectly via the axons of other neurons. When active channels were added, gap junctions could make action potential propagation along the thin axons unreliable. Increased sodium and decreased potassium channel densities in the initial axon segment improved action potential propagation. Modelling suggested that the single spike firing to step current injection observed in whole-cell recordings is not a cellular property but a dynamic consequence of shunting resulting from electrical coupling. Without electrical coupling, firing of the population during depolarising current was unsynchronised; with coupling, the population showed synchronous recruitment and rhythmic firing. When activated instead by increasing levels of modelled sensory pathway input, the population without electrical coupling was recruited incrementally to unpatterned activity. However, when coupled, the population was recruited all-or-none at threshold into a rhythmic swimming pattern: the tadpole “decided” to swim. Modelling emphasises uncertainties about fine unmyelinated axon physiology but, when informed by biological data, makes general predictions about gap junctions: locations close to the soma; relatively small numbers; many indirect connections between neurons; cause of action potential propagation failure in fine axons; misleading alteration of intrinsic firing properties. Modelling also indicates that electrical coupling within a population can synchronize recruitment of neurons and their pacemaker firing during rhythmic activity. Some groups of nerve cells in the brain are connected to each other electrically where their processes make contact and form specialized “gap” junctions. The simplest function of electrical connections is to make activity propagate faster by avoiding the delays resulting from chemical messengers at synaptic connections. In other cases, especially in higher brain regions where more spread out nerve cells may be connected by their axons, the function of electrical coupling is less clear. To understand this type of electrical connection better we have built computer models of a group of electrically coupled nerve cells in the brain which control swimming in very young frog tadpoles. We show that the coupling can be indirect, via other members of the group, and can profoundly influence the properties of the nerve cells which would be recorded during real experiments. The main role of the coupling is to synchronise the firing of the group so they are all recruited together when the tadpole is stimulated and then fire in a rhythm suitable to drive swimming movements. The results from this simple animal raise issues which will help to understand coupling in more complex brains.
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Yao C, Vanderpool KG, Delfiner M, Eddy V, Lucaci AG, Soto-Riveros C, Yasumura T, Rash JE, Pereda AE. Electrical synaptic transmission in developing zebrafish: properties and molecular composition of gap junctions at a central auditory synapse. J Neurophysiol 2014; 112:2102-13. [PMID: 25080573 PMCID: PMC4274921 DOI: 10.1152/jn.00397.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/29/2014] [Indexed: 11/22/2022] Open
Abstract
In contrast to the knowledge of chemical synapses, little is known regarding the properties of gap junction-mediated electrical synapses in developing zebrafish, which provide a valuable model to study neural function at the systems level. Identifiable "mixed" (electrical and chemical) auditory synaptic contacts known as "club endings" on Mauthner cells (2 large reticulospinal neurons involved in tail-flip escape responses) allow exploration of electrical transmission in fish. Here, we show that paralleling the development of auditory responses, electrical synapses at these contacts become anatomically identifiable at day 3 postfertilization, reaching a number of ∼6 between days 4 and 9. Furthermore, each terminal contains ∼18 gap junctions, representing between 2,000 and 3,000 connexon channels formed by the teleost homologs of mammalian connexin 36. Electrophysiological recordings revealed that gap junctions at each of these contacts are functional and that synaptic transmission has properties that are comparable with those of adult fish. Thus a surprisingly small number of mixed synapses are responsible for the acquisition of auditory responses by the Mauthner cells, and these are likely sufficient to support escape behaviors at early developmental stages.
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Affiliation(s)
- Cong Yao
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Kimberly G Vanderpool
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado; and
| | - Matthew Delfiner
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Vanessa Eddy
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Alexander G Lucaci
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Carolina Soto-Riveros
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Thomas Yasumura
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado; and
| | - John E Rash
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado; and Program in Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, Colorado
| | - Alberto E Pereda
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York;
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Carlisle TC, Ribera AB. Connexin 35b expression in the spinal cord of Danio rerio embryos and larvae. J Comp Neurol 2014; 522:861-75. [PMID: 23939687 DOI: 10.1002/cne.23449] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/10/2013] [Accepted: 08/02/2013] [Indexed: 11/11/2022]
Abstract
Electrical synapses are expressed prominently in the developing and mature nervous systems. Unlike chemical synapses, little is known about the developmental role of electrical synapses, reflecting the limitations imposed by the lack of selective pharmacological blockers. At a molecular level, the building blocks of electrical synapses are connexin proteins. In this study, we report the expression pattern for neuronally expressed connexin 35b (cx35b), the zebrafish orthologue of mammalian connexin (Cx) 36. We find that cx35b is expressed at the time of neural induction, indicating a possible early role in neural progenitor cells. Additionally, cx35b localizes to the ventral spinal cord during embryonic and early larval stages. We detect cx35b mRNA in secondary motor neurons (SMNs) and interneurons. We identified the premotor circumferential descending (CiD) interneuron as one interneuron subtype expressing cx35b. In addition, cx35b is present in other ventral interneurons of unknown subtype(s). This early expression of cx35b in SMNs and CiDs suggests a possible role in motor network function during embryonic and larval stages.
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Affiliation(s)
- Tara C Carlisle
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045; Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045; Colorado Clinical and Translational Sciences Institute, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045; Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045
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