1
|
Dey S, Ghosh-Roy A. In vivo Assessment of Microtubule Dynamics and Orientation in Caenorhabditis elegans Neurons. J Vis Exp 2021:10.3791/62744. [PMID: 34866634 PMCID: PMC7614928 DOI: 10.3791/62744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In neurons, microtubule orientation has been a key assessor to identify axons that have plus-end out microtubules and dendrites that generally have mixed orientation. Here we describe methods to label, image, and analyze the microtubule dynamics and growth during the development and regeneration of touch neurons in C. elegans. Using genetically encoded fluorescent reporters of microtubule tips, we imaged the axonal microtubules. The local changes in microtubule behavior that initiates axon regeneration following axotomy can be quantified using this protocol. This assay is adaptable to other neurons and genetic backgrounds to investigate the regulation of microtubule dynamics in various cellular processes.
Collapse
|
2
|
Harreguy MB, Marfil V, Grooms NWF, Gabel CV, Chung SH, Haspel G. Ytterbium-doped fibre femtosecond laser offers robust operation with deep and precise microsurgery of C. elegans neurons. Sci Rep 2020; 10:4545. [PMID: 32161333 PMCID: PMC7066168 DOI: 10.1038/s41598-020-61479-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/25/2020] [Indexed: 11/15/2022] Open
Abstract
Laser microsurgery is a powerful tool for neurobiology, used to ablate cells and sever neurites in-vivo. We compare a relatively new laser source to two well-established designs. Rare-earth-doped mode-locked fibre lasers that produce high power pulses recently gained popularity for industrial uses. Such systems are manufactured to high standards of robustness and low maintenance requirements typical of solid-state lasers. We demonstrate that an Ytterbium-doped fibre femtosecond laser is comparable in precision to a Ti:Sapphire femtosecond laser (1-2 micrometres), but with added operational reliability. Due to the lower pulse energy required to ablate, it is more precise than a solid-state nanosecond laser. Due to reduced scattering of near infrared light, it can lesion deeper (more than 100 micrometres) in tissue. These advantages are not specific to the model system ablated for our demonstration, namely neurites in the nematode C. elegans, but are applicable to other systems and transparent tissue where a precise micron-resolution dissection is required.
Collapse
Affiliation(s)
- M B Harreguy
- New Jersey Institute of Technology and Rutgers University, Federated Department of Biological Sciences and New Jersey Institute of Technology, Institute of Brain Research and Neuroscience, 100 Summit St, Newark, NJ, 07102, USA
| | - V Marfil
- New Jersey Institute of Technology and Rutgers University, Federated Department of Biological Sciences and New Jersey Institute of Technology, Institute of Brain Research and Neuroscience, 100 Summit St, Newark, NJ, 07102, USA
| | - N W F Grooms
- Northeastern University, Department of Bioengineering, 360 Huntington Avenue, Boston, MA, 02115, USA
| | - C V Gabel
- Department of Physiology and Biophysics and Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine and Boston University Photonics Center, 700 Albany St, Boston, Massachusetts, 02215, USA
| | - S H Chung
- Northeastern University, Department of Bioengineering, 360 Huntington Avenue, Boston, MA, 02115, USA.
| | - G Haspel
- New Jersey Institute of Technology and Rutgers University, Federated Department of Biological Sciences and New Jersey Institute of Technology, Institute of Brain Research and Neuroscience, 100 Summit St, Newark, NJ, 07102, USA.
| |
Collapse
|
3
|
Li D, Li F, Guttipatti P, Song Y. A Drosophila In Vivo Injury Model for Studying Neuroregeneration in the Peripheral and Central Nervous System. J Vis Exp 2018:57557. [PMID: 29781994 PMCID: PMC6101115 DOI: 10.3791/57557] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The regrowth capacity of damaged neurons governs neuroregeneration and functional recovery after nervous system trauma. Over the past few decades, various intrinsic and extrinsic inhibitory factors involved in the restriction of axon regeneration have been identified. However, simply removing these inhibitory cues is insufficient for successful regeneration, indicating the existence of additional regulatory machinery. Drosophila melanogaster, the fruit fly, shares evolutionarily conserved genes and signaling pathways with vertebrates, including humans. Combining the powerful genetic toolbox of flies with two-photon laser axotomy/dendriotomy, we describe here the Drosophila sensory neuron - dendritic arborization (da) neuron injury model as a platform for systematically screening for novel regeneration regulators. Briefly, this paradigm includes a) the preparation of larvae, b) lesion induction to dendrite(s) or axon(s) using a two-photon laser, c) live confocal imaging post-injury and d) data analysis. Our model enables highly reproducible injury of single labeled neurons, axons, and dendrites of well-defined neuronal subtypes, in both the peripheral and central nervous system.
Collapse
Affiliation(s)
- Dan Li
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia
| | - Feng Li
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia
| | - Pavithran Guttipatti
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia
| | - Yuanquan Song
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia; Department of Pathology and Laboratory Medicine, University of Pennsylvania;
| |
Collapse
|
4
|
Basu A, Dey S, Puri D, Das Saha N, Sabharwal V, Thyagarajan P, Srivastava P, Koushika SP, Ghosh-Roy A. let-7 miRNA controls CED-7 homotypic adhesion and EFF-1-mediated axonal self-fusion to restore touch sensation following injury. Proc Natl Acad Sci U S A 2017; 114:E10206-E10215. [PMID: 29109254 PMCID: PMC5703274 DOI: 10.1073/pnas.1704372114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuronal injury often leads to devastating consequences such as loss of senses or locomotion. Restoration of function after injury relies on whether the injured axons can find their target cells. Although fusion between injured proximal axon and distal fragment has been observed in many organisms, its functional significance is not clear. Here, using Caenorhabditis elegans mechanosensory neurons, we address this question. Using two femtosecond lasers simultaneously, we could scan and sever posterior lateral microtubule neurons [posterior lateral microtubules (PLMs)] on both sides of the worm. We showed that axotomy of both PLMs leads to a dramatic loss of posterior touch sensation. During the regenerative phase, only axons that fuse to their distal counterparts contribute to functional recovery. Loss of let-7 miRNA promotes functional restoration in both larval and adult stages. In the L4 stage, loss of let-7 increases fusion events by increasing the mRNA level of one of the cell-recognition molecules, CED-7. The ability to establish cytoplasmic continuity between the proximal and distal ends declines with age. Loss of let-7 overcomes this barrier by promoting axonal transport and enrichment of the EFF-1 fusogen at the growing tip of cut processes. Our data reveal the functional property of a regenerating neuron.
Collapse
Affiliation(s)
- Atrayee Basu
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Shirshendu Dey
- Bruker India Scientific Private Ltd, New Delhi 110019, India
| | - Dharmendra Puri
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Nilanjana Das Saha
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Vidur Sabharwal
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400 005, India
| | - Pankajam Thyagarajan
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Prerna Srivastava
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | | | - Anindya Ghosh-Roy
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India;
- Wellcome Trust-Department of Biotechnology India Alliance, Banjara Hills, Hyderabad, Telangana 500034, India
| |
Collapse
|
5
|
Chisholm AD, Hutter H, Jin Y, Wadsworth WG. The Genetics of Axon Guidance and Axon Regeneration in Caenorhabditis elegans. Genetics 2016; 204:849-882. [PMID: 28114100 PMCID: PMC5105865 DOI: 10.1534/genetics.115.186262] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/06/2016] [Indexed: 11/18/2022] Open
Abstract
The correct wiring of neuronal circuits depends on outgrowth and guidance of neuronal processes during development. In the past two decades, great progress has been made in understanding the molecular basis of axon outgrowth and guidance. Genetic analysis in Caenorhabditis elegans has played a key role in elucidating conserved pathways regulating axon guidance, including Netrin signaling, the slit Slit/Robo pathway, Wnt signaling, and others. Axon guidance factors were first identified by screens for mutations affecting animal behavior, and by direct visual screens for axon guidance defects. Genetic analysis of these pathways has revealed the complex and combinatorial nature of guidance cues, and has delineated how cues guide growth cones via receptor activity and cytoskeletal rearrangement. Several axon guidance pathways also affect directed migrations of non-neuronal cells in C. elegans, with implications for normal and pathological cell migrations in situations such as tumor metastasis. The small number of neurons and highly stereotyped axonal architecture of the C. elegans nervous system allow analysis of axon guidance at the level of single identified axons, and permit in vivo tests of prevailing models of axon guidance. C. elegans axons also have a robust capacity to undergo regenerative regrowth after precise laser injury (axotomy). Although such axon regrowth shares some similarities with developmental axon outgrowth, screens for regrowth mutants have revealed regeneration-specific pathways and factors that were not identified in developmental screens. Several areas remain poorly understood, including how major axon tracts are formed in the embryo, and the function of axon regeneration in the natural environment.
Collapse
Affiliation(s)
| | - Harald Hutter
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, and
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
- Department of Pathology and Laboratory Medicine, Howard Hughes Medical Institute, Chevy Chase, Maryland, and
| | - William G Wadsworth
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| |
Collapse
|
6
|
Byrne AB, Hammarlund M. Axon regeneration in C. elegans: Worming our way to mechanisms of axon regeneration. Exp Neurol 2016; 287:300-309. [PMID: 27569538 DOI: 10.1016/j.expneurol.2016.08.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/19/2016] [Accepted: 08/24/2016] [Indexed: 12/12/2022]
Abstract
How axons repair themselves after injury is a fundamental question in neurobiology. With its conserved genome, relatively simple nervous system, and transparent body, C. elegans has recently emerged as a productive model to uncover the cellular mechanisms that regulate and execute axon regeneration. In this review, we discuss the strengths and weaknesses of the C. elegans model of regeneration. We explore the technical advances that enable the use of C. elegans for in vivo regeneration studies, review findings in C. elegans that have contributed to our understanding of the regeneration response across species, discuss the potential of C. elegans research to provide insight into mechanisms that function in the injured mammalian nervous system, and present potential future directions of axon regeneration research using C. elegans.
Collapse
Affiliation(s)
- Alexandra B Byrne
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Marc Hammarlund
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States.
| |
Collapse
|
7
|
Abstract
Axons of the mammalian CNS lose the ability to regenerate soon after development due to both an inhibitory CNS environment and the loss of cell-intrinsic factors necessary for regeneration. The complex molecular events required for robust regeneration of mature neurons are not fully understood, particularly in vivo. To identify genes affecting axon regeneration in Caenorhabditis elegans, we performed both an RNAi-based screen for defective motor axon regeneration in unc-70/β-spectrin mutants and a candidate gene screen. From these screens, we identified at least 50 conserved genes with growth-promoting or growth-inhibiting functions. Through our analysis of mutants, we shed new light on certain aspects of regeneration, including the role of β-spectrin and membrane dynamics, the antagonistic activity of MAP kinase signaling pathways, and the role of stress in promoting axon regeneration. Many gene candidates had not previously been associated with axon regeneration and implicate new pathways of interest for therapeutic intervention.
Collapse
|
8
|
Mishra B, Ghannad-Rezaie M, Li J, Wang X, Hao Y, Ye B, Chronis N, Collins CA. Using microfluidics chips for live imaging and study of injury responses in Drosophila larvae. J Vis Exp 2014:e50998. [PMID: 24562098 PMCID: PMC4117361 DOI: 10.3791/50998] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Live imaging is an important technique for studying cell biological processes, however this can be challenging in live animals. The translucent cuticle of the Drosophila larva makes it an attractive model organism for live imaging studies. However, an important challenge for live imaging techniques is to noninvasively immobilize and position an animal on the microscope. This protocol presents a simple and easy to use method for immobilizing and imaging Drosophila larvae on a polydimethylsiloxane (PDMS) microfluidic device, which we call the 'larva chip'. The larva chip is comprised of a snug-fitting PDMS microchamber that is attached to a thin glass coverslip, which, upon application of a vacuum via a syringe, immobilizes the animal and brings ventral structures such as the nerve cord, segmental nerves, and body wall muscles, within close proximity to the coverslip. This allows for high-resolution imaging, and importantly, avoids the use of anesthetics and chemicals, which facilitates the study of a broad range of physiological processes. Since larvae recover easily from the immobilization, they can be readily subjected to multiple imaging sessions. This allows for longitudinal studies over time courses ranging from hours to days. This protocol describes step-by-step how to prepare the chip and how to utilize the chip for live imaging of neuronal events in 3rd instar larvae. These events include the rapid transport of organelles in axons, calcium responses to injury, and time-lapse studies of the trafficking of photo-convertible proteins over long distances and time scales. Another application of the chip is to study regenerative and degenerative responses to axonal injury, so the second part of this protocol describes a new and simple procedure for injuring axons within peripheral nerves by a segmental nerve crush.
Collapse
Affiliation(s)
- Bibhudatta Mishra
- Department of Molecular, Cellular and Developmental Biology, University of Michigan
| | | | - Jiaxing Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan
| | - Xin Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan
| | - Yan Hao
- Department of Molecular, Cellular and Developmental Biology, University of Michigan
| | - Bing Ye
- Life Sciences Institute, University of Michigan; Department of Cell and Developmental Biology, University of Michigan
| | - Nikos Chronis
- Department of Biomedical Engineering, University of Michigan; Department of Mechanical Engineering, University of Michigan
| | - Catherine A Collins
- Department of Molecular, Cellular and Developmental Biology, University of Michigan;
| |
Collapse
|
9
|
Abstract
Axon regeneration is a medically relevant process that can repair damaged neurons. This review describes current progress in understanding axon regeneration in the model organism Caenorhabditis elegans. Factors that regulate axon regeneration in C. elegans have broadly similar roles in vertebrate neurons. This means that using C. elegans as a tool to leverage discovery is a legitimate strategy for identifying conserved mechanisms of axon regeneration.
Collapse
Affiliation(s)
- Rachid El Bejjani
- Department of Genetics, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University, New Haven, Connecticut 06510, USA
| | | |
Collapse
|