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Xu Y, Chao A, Rinaldin M, Kickuth A, Brugués J, Di Talia S. The cell cycle oscillator and spindle length set the speed of chromosome separation in Drosophila embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.17.598879. [PMID: 38948726 PMCID: PMC11212860 DOI: 10.1101/2024.06.17.598879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Anaphase is tightly controlled in space and time to ensure proper separation of chromosomes. The mitotic spindle, the self-organized microtubule structure driving chromosome segregation, scales in size with the available cytoplasm. Yet, the relationship between spindle size and chromosome movement remains poorly understood. Here, we address how the movement of chromosomes changes during the cleavage divisions of the Drosophila blastoderm. We show that the speed of chromosome separation gradually decreases during the 4 nuclear divisions of the blastoderm. This reduction in speed is accompanied by a similar reduction in the length of the spindle, thus ensuring that these two quantities are tightly linked. Using a combination of genetic and quantitative imaging approaches, we find that two processes contribute to controlling the speed at which chromosomes move at mitotic exit: the activity of molecular motors important for microtubule depolymerization and the cell cycle oscillator. Specifically, we found that the levels of Klp10A, Klp67A, and Klp59C, three kinesin-like proteins important for microtubule depolymerization, contribute to setting the speed of chromosome separation. This observation is supported by quantification of microtubule dynamics indicating that poleward flux rate scales with the length of the spindle. Perturbations of the cell cycle oscillator using heterozygous mutants of mitotic kinases and phosphatases revealed that the duration of anaphase increases during the blastoderm cycles and is the major regulator of chromosome velocity. Thus, our work suggests a potential link between the biochemical rate of mitotic exit and the forces exerted by the spindle. Collectively, we propose that the cell cycle oscillator and spindle length set the speed of chromosome separation in anaphase.
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Affiliation(s)
- Yitong Xu
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
| | - Anna Chao
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
| | - Melissa Rinaldin
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Alison Kickuth
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Jan Brugués
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
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2
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Clark MG, Ma S, Mahapatra S, Mohn KJ, Zhang C. Chemical-imaging-guided optical manipulation of biomolecules. Front Chem 2023; 11:1198670. [PMID: 37214479 PMCID: PMC10196011 DOI: 10.3389/fchem.2023.1198670] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 04/20/2023] [Indexed: 05/24/2023] Open
Abstract
Chemical imaging via advanced optical microscopy technologies has revealed remarkable details of biomolecules in living specimens. However, the ways to control chemical processes in biological samples remain preliminary. The lack of appropriate methods to spatially regulate chemical reactions in live cells in real-time prevents investigation of site-specific molecular behaviors and biological functions. Chemical- and site-specific control of biomolecules requires the detection of chemicals with high specificity and spatially precise modulation of chemical reactions. Laser-scanning optical microscopes offer great platforms for high-speed chemical detection. A closed-loop feedback control system, when paired with a laser scanning microscope, allows real-time precision opto-control (RPOC) of chemical processes for dynamic molecular targets in live cells. In this perspective, we briefly review recent advancements in chemical imaging based on laser scanning microscopy, summarize methods developed for precise optical manipulation, and highlight a recently developed RPOC technology. Furthermore, we discuss future directions of precision opto-control of biomolecules.
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Affiliation(s)
| | - Seohee Ma
- Department of Chemistry, West Lafayette, IN, United States
| | | | | | - Chi Zhang
- Department of Chemistry, West Lafayette, IN, United States
- Purdue Center for Cancer Research, West Lafayette, IN, United States
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States
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3
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Haig H, Sidorenko P, Thorne R, Wise F. Megawatt pulses from an all-fiber and self-starting femtosecond oscillator. OPTICS LETTERS 2022; 47:762-765. [PMID: 35167519 DOI: 10.1364/ol.450313] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
Mamyshev oscillators produce high-performance pulses, but technical and practical issues render them unsuitable for widespread use. Here we present a Mamyshev oscillator with several key design features that enable self-starting operation and unprecedented performance and simplicity from an all-fiber laser. The laser generates 110 nJ pulses that compress to 40 fs and 80 nJ with a grating pair. The pulse energy and duration are both the best achieved by a femtosecond all-fiber laser to date, to our knowledge, and the resulting peak power of 1.5 MW is 20 times higher than that of prior all-fiber, self-starting lasers. The simplicity of the design, ease of use, and pulse performance make this laser an attractive tool for practical applications.
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4
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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.
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Rieckhoff EM, Berndt F, Elsner M, Golfier S, Decker F, Ishihara K, Brugués J. Spindle Scaling Is Governed by Cell Boundary Regulation of Microtubule Nucleation. Curr Biol 2020; 30:4973-4983.e10. [DOI: 10.1016/j.cub.2020.10.093] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/11/2020] [Accepted: 10/29/2020] [Indexed: 02/08/2023]
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6
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Wang F, Pan C, Sun J, Wang Q, Lu Y, Jiang L. Direct observation of structure-assisted filament splitting during ultrafast multiple-pulse laser ablation. OPTICS EXPRESS 2019; 27:10050-10057. [PMID: 31045151 DOI: 10.1364/oe.27.010050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 03/14/2019] [Indexed: 06/09/2023]
Abstract
Laser-induced plasma evolution in fused silica through multipulse laser ablation was studied using pump-probe technology. Filament splitting was observed in the early stage of plasma evolution (before ~300 fs). This phenomenon can be attributed to competition between laser divergent propagation induced by a pre-pulse-induced crater and the nonlinear self-focusing effect. This effect was validated through simulation results. With the increasing pulse number, the appearance of filament peak electron density was postponed. Furthermore, a second peak in the filament and peak position separation were observed because of an optical path difference between the lasers propagating from the crater center and edge. The experimental results revealed the influence of a prepulse-induced structure on the energy distribution of subsequent pulses, which are essential for understanding the mechanism of laser-material interactions, particularly in ultrafast multiple-pulse laser ablation.
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7
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Baskey SJ, Andreana M, Lanteigne E, Ridsdale A, Stolow A, Schweitzer ME. Pre-Clinical Translation of Second Harmonic Microscopy of Meniscal and Articular Cartilage Using a Prototype Nonlinear Microendoscope. IEEE JOURNAL OF TRANSLATIONAL ENGINEERING IN HEALTH AND MEDICINE-JTEHM 2018; 7:1800211. [PMID: 30701146 PMCID: PMC6342420 DOI: 10.1109/jtehm.2018.2889496] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/05/2018] [Accepted: 11/30/2018] [Indexed: 11/06/2022]
Abstract
Previous studies using nonlinear microscopy have demonstrated that osteoarthritis (OA) is characterized by the gradual replacement of Type II collagen with Type I collagen. The objective of this study was to develop a prototype nonlinear laser scanning microendoscope capable of resolving the structural differences of collagen in various orthopaedically relevant cartilaginous surfaces. The current prototype developed a miniaturized femtosecond laser scanning instrument, mounted on an articulated positioning system, capable of both conventional arthroscopy and second-harmonic laser-scanning microscopy. Its optical system includes a multi-resolution optical system using a gradient index objective lens and a customized multi-purpose fiber optic sheath to maximize the collection of backscattered photons or provide joint capsule illumination. The stability and suitability of the prototype arthroscope to approach and image cartilage were evaluated through preliminary testing on fresh, minimally processed, and partially intact porcine knee joints. Image quality was sufficient to distinguish between hyaline cartilage and fibrocartilage through unique Type I and Type II collagen-specific characteristics. Imaging the meniscus revealed that the system was able to visualize differences in the collagen arrangement between the superficial and lamellar layers. Such detailed in vivo imaging of the cartilage surfaces could obviate the need to perform biopsies for ex vivo histological analysis in the future, and provide an alternative to conventional external imaging to characterize and diagnose progressive and degenerative cartilage diseases such as OA. Moreover, this system is readily customizable and may provide a suitable and modular platform for developing additional tools utilizing femtosecond lasers for tissue cutting within the familiar confines of two or three portal arthroscopy techniques.
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Affiliation(s)
- Stephen J Baskey
- Faculty of MedicineUniversity of OttawaOttawaONK1H 8M5Canada.,Department of Mechanical EngineeringUniversity of OttawaOttawaONK1N 6N5Canada.,Emerging Technologies Division, Molecular Photonics GroupNational Research Council CanadaOttawaONK1A 0R6Canada
| | - Marco Andreana
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna1090ViennaAustria
| | - Eric Lanteigne
- Department of Mechanical EngineeringUniversity of OttawaOttawaONK1N 6N5Canada
| | - Andrew Ridsdale
- Emerging Technologies Division, Molecular Photonics GroupNational Research Council CanadaOttawaONK1A 0R6Canada
| | - Albert Stolow
- Emerging Technologies Division, Molecular Photonics GroupNational Research Council CanadaOttawaONK1A 0R6Canada.,Department of PhysicsUniversity of OttawaOttawaONK1N 6N5Canada.,Department of ChemistryUniversity of OttawaOttawaONK1N 6N5Canada
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8
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Penilla EH, Devia-Cruz LF, Duarte MA, Hardin CL, Kodera Y, Garay JE. Gain in polycrystalline Nd-doped alumina: leveraging length scales to create a new class of high-energy, short pulse, tunable laser materials. LIGHT, SCIENCE & APPLICATIONS 2018; 7:33. [PMID: 30839607 PMCID: PMC6107005 DOI: 10.1038/s41377-018-0023-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/28/2018] [Accepted: 04/15/2018] [Indexed: 05/05/2023]
Abstract
Traditionally accepted design paradigms dictate that only optically isotropic (cubic) crystal structures with high equilibrium solubilities of optically active ions are suitable for polycrystalline laser gain media. The restriction of symmetry is due to light scattering caused by randomly oriented anisotropic crystals, whereas the solubility problem arises from the need for sufficient active dopants in the media. These criteria limit material choices and exclude materials that have superior thermo-mechanical properties than state-of-the-art laser materials. Alumina (Al2O3) is an ideal example; it has a higher fracture strength and thermal conductivity than today's gain materials, which could lead to revolutionary laser performance. However, alumina has uniaxial optical proprieties, and the solubility of rare earths (REs) is two-to-three orders of magnitude lower than the dopant concentrations in typical RE-based gain media. We present new strategies to overcome these obstacles and demonstrate gain in a RE-doped alumina (Nd:Al2O3) for the first time. The key insight relies on tailoring the crystallite size to other important length scales-the wavelength of light and interatomic dopant distances, which minimize optical losses and allow successful Nd doping. The result is a laser gain medium with a thermo-mechanical figure of merit of R s~19,500 Wm-1 a 24-fold and 19,500-fold improvements over the high-energy-laser leaders Nd:YAG (R s~800 Wm-1) and Nd:Glass (R s~1 Wm-1), respectively. Moreover, the emission bandwidth of Nd:Al2O3 is broad: ~13 THz. The successful demonstration of gain and high bandwidth in a medium with superior R s can lead to the development of lasers with previously unobtainable high-peak powers, short pulses, tunability, and high-duty cycles.
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Affiliation(s)
- Elias H. Penilla
- Advanced Materials Processing and Synthesis (AMPS) Laboratory, UC San Diego, La Jolla, CA 92093 USA
- Materials Science & Engineering and Mechanical & Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 USA
| | - Luis F. Devia-Cruz
- Advanced Materials Processing and Synthesis (AMPS) Laboratory, UC San Diego, La Jolla, CA 92093 USA
| | - Matthew A. Duarte
- Advanced Materials Processing and Synthesis (AMPS) Laboratory, UC San Diego, La Jolla, CA 92093 USA
- Materials Science & Engineering and Mechanical & Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 USA
| | - Corey L. Hardin
- Advanced Materials Processing and Synthesis (AMPS) Laboratory, UC San Diego, La Jolla, CA 92093 USA
| | - Yasuhiro Kodera
- Advanced Materials Processing and Synthesis (AMPS) Laboratory, UC San Diego, La Jolla, CA 92093 USA
- Materials Science & Engineering and Mechanical & Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 USA
| | - Javier E. Garay
- Advanced Materials Processing and Synthesis (AMPS) Laboratory, UC San Diego, La Jolla, CA 92093 USA
- Materials Science & Engineering and Mechanical & Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 USA
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9
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Buđa R, Vukušić K, Tolić IM. Dissection and characterization of microtubule bundles in the mitotic spindle using femtosecond laser ablation. Methods Cell Biol 2017; 139:81-101. [PMID: 28215341 DOI: 10.1016/bs.mcb.2016.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mitotic spindle is a highly organized and dynamic structure required for segregation of the genetic material into two daughter cells. Although most of the individual players involved in building the spindle have been characterized in vitro, a general understanding of how all of the spindle players act together in vivo is still missing. Hence, in recent years, experiments have focused on introducing mechanical perturbations of the spindle on a micron scale, thereby providing insight into its function and organization, as well as into forces acting in the spindle. Among different types of mechanical perturbations, optical ones are more flexible, less invasive, and more precise than other approaches. In this chapter, we describe a detailed protocol for cutting the microtubule bundles in human cells using a near-infrared femtosecond laser. This type of laser microsurgery provides the ability to precisely sever a single microtubule bundle while preserving spindle integrity and dynamics. Furthermore, we describe quantitative measurements obtained from the response of a severed microtubule bundle to laser ablation, which reveal the structure and function of individual parts of the spindle, such as the bridging fiber connecting sister k-fibers. Finally, the method described here can be easily combined with other quantitative techniques to address the complexity of the spindle.
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Affiliation(s)
- R Buđa
- Ruđer Bošković Institute, Zagreb, Croatia
| | - K Vukušić
- Ruđer Bošković Institute, Zagreb, Croatia
| | - I M Tolić
- Ruđer Bošković Institute, Zagreb, Croatia
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10
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Ablation-cooled material removal with ultrafast bursts of pulses. Nature 2016; 537:84-88. [DOI: 10.1038/nature18619] [Citation(s) in RCA: 414] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 05/24/2016] [Indexed: 11/08/2022]
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11
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Stirman JN, Harker B, Lu H, Crane MM. Animal microsurgery using microfluidics. Curr Opin Biotechnol 2013; 25:24-9. [PMID: 24484877 DOI: 10.1016/j.copbio.2013.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 08/14/2013] [Indexed: 10/26/2022]
Abstract
Small multicellular genetic organisms form a central part of modern biological research. Using these small organisms provides significant advantages in genetic tractability, manipulation, lifespan and cost. Although the small size is generally advantageous, it can make procedures such as surgeries both time consuming and labor intensive. Over the past few years there have been dramatic improvements in microfluidic technologies that enable significant improvements in microsurgery and interrogation of small multicellular model organisms.
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Affiliation(s)
- Jeffrey N Stirman
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, USA; Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC, USA
| | - Bethany Harker
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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12
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Antkowiak M, Torres-Mapa ML, Stevenson DJ, Dholakia K, Gunn-Moore FJ. Femtosecond optical transfection of individual mammalian cells. Nat Protoc 2013; 8:1216-33. [PMID: 23722260 DOI: 10.1038/nprot.2013.071] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Laser-mediated gene transfection into mammalian cells has recently emerged as a powerful alternative to more traditional transfection techniques. In particular, the use of a femtosecond-pulsed laser operating in the near-infrared (NIR) region has been proven to provide single-cell selectivity, localized delivery, low toxicity and consistent performance. This approach can easily be integrated with advanced multimodal live-cell microscopy and micromanipulation techniques. The efficiency of this technique depends on an understanding by the user of both biology and physics. Therefore, in this protocol we discuss the subtleties that apply to both fields, including sample preparation, alignment and calibration of laser optics and their integration into a microscopy platform. The entire protocol takes ~5 d to complete, from the initial setup of the femtosecond optical transfection system to the final stage of fluorescence imaging to assay for successful expression of the gene of interest.
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Affiliation(s)
- Maciej Antkowiak
- Scottish Universities Life Sciences Alliance (SULSA), School of Biology, University of St. Andrews, St. Andrews, UK
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13
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Sivagnanam V, Gijs MAM. Exploring Living Multicellular Organisms, Organs, and Tissues Using Microfluidic Systems. Chem Rev 2013; 113:3214-47. [DOI: 10.1021/cr200432q] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | - Martin A. M. Gijs
- Laboratory
of Microsystems, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne,
Switzerland
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14
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Kizil C, Kaslin J, Kroehne V, Brand M. Adult neurogenesis and brain regeneration in zebrafish. Dev Neurobiol 2012; 72:429-61. [DOI: 10.1002/dneu.20918] [Citation(s) in RCA: 249] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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Abstract
Laser killing of cell nuclei has long been a powerful means of examining the roles of individual cells in C. elegans. Advances in genetics, laser technology, and imaging have further expanded the capabilities and usefulness of laser surgery. Here, we review the implementation and application of currently used methods for target edoptical disruption in C. elegans.
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Williams W, Nix P, Bastiani M. Constructing a low-budget laser axotomy system to study axon regeneration in C. elegans. J Vis Exp 2011:3331. [PMID: 22126922 PMCID: PMC3308599 DOI: 10.3791/3331] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Laser axotomy followed by time-lapse microscopy is a sensitive assay for axon regeneration phenotypes in C. elegans(1). The main difficulty of this assay is the perceived cost ($25-100K) and technical expertise required for implementing a laser ablation system(2,3). However, solid-state pulse lasers of modest costs (<$10K) can provide robust performance for laser ablation in transparent preparations where target axons are "close" to the tissue surface. Construction and alignment of a system can be accomplished in a day. The optical path provided by light from the focused condenser to the ablation laser provides a convenient alignment guide. An intermediate module with all optics removed can be dedicated to the ablation laser and assures that no optical elements need be moved during a laser ablation session. A dichroic in the intermediate module allows simultaneous imaging and laser ablation. Centering the laser beam to the outgoing beam from the focused microscope condenser lens guides the initial alignment of the system. A variety of lenses are used to condition and expand the laser beam to fill the back aperture of the chosen objective lens. Final alignment and testing is performed with a front surface mirrored glass slide target. Laser power is adjusted to give a minimum size ablation spot (<1 um). The ablation spot is centered with fine adjustments of the last kinematically mounted mirror to cross hairs fixed in the imaging window. Laser power for axotomy will be approximately 10X higher than needed for the minimum ablation spot on the target slide (this may vary with the target you use). Worms can be immobilized for laser axotomy and time-lapse imaging by mounting on agarose pads (or in microfluidic chambers(4)). Agarose pads are easily made with 10% agarose in balanced saline melted in a microwave. A drop of molten agarose is placed on a glass slide and flattened with another glass slide into a pad approximately 200 um thick (a single layer of time tape on adjacent slides is used as a spacer). A "Sharpie" cap is used to cut out a uniformed diameter circular pad of 13 mm. Anesthetic (1 ul Muscimol 20mM) and Microspheres (Chris Fang-Yen personal communication) (1 ul 2.65% Polystyrene 0.1 um in water) are added to the center of the pad followed by 3-5 worms oriented so they are lying on their left sides. A glass coverslip is applied and then Vaseline is used to seal the coverslip and prevent evaporation of the sample.
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Kunik D, Dion C, Ozaki T, Levin LA, Costantino S. Laser-based single-axon transection for high-content axon injury and regeneration studies. PLoS One 2011; 6:e26832. [PMID: 22073205 PMCID: PMC3206876 DOI: 10.1371/journal.pone.0026832] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 10/05/2011] [Indexed: 01/15/2023] Open
Abstract
The investigation of the regenerative response of the neurons to axonal injury is essential to the development of new axoprotective therapies. Here we study the retinal neuronal RGC-5 cell line after laser transection, demonstrating that the ability of these cells to initiate a regenerative response correlates with axon length and cell motility after injury. We show that low energy picosecond laser pulses can achieve transection of unlabeled single axons in vitro and precisely induce damage with micron precision. We established the conditions to achieve axon transection, and characterized RGC-5 axon regeneration and cell body response using time-lapse microscopy. We developed an algorithm to analyze cell trajectories and established correlations between cell motility after injury, axon length, and the initiation of the regeneration response. The characterization of the motile response of axotomized RGC-5 cells showed that cells that were capable of repair or regrowth of damaged axons migrated more slowly than cells that could not. Moreover, we established that RGC-5 cells with long axons could not recover their injured axons, and such cells were much more motile. The platform we describe allows highly controlled axonal damage with subcellular resolution and the performance of high-content screening in cell cultures.
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Affiliation(s)
- Darío Kunik
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Institut de Génie Biomédical, Université de Montréal, Montréal, Quebec, Canada
| | - Carolyne Dion
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Energie Materiaux et Communications, Institut National de la Recherche Scientifique, Quebec City, Quebec, Canada
| | - Tsuneyuki Ozaki
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Energie Materiaux et Communications, Institut National de la Recherche Scientifique, Quebec City, Quebec, Canada
| | - Leonard A. Levin
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Département d'Ophtalmologie Université de Montréal, Montréal, Quebec, Canada
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Santiago Costantino
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Institut de Génie Biomédical, Université de Montréal, Montréal, Quebec, Canada
- Département d'Ophtalmologie Université de Montréal, Montréal, Quebec, Canada
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18
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Yanik MF, Rohde CB, Pardo-Martin C. Technologies for Micromanipulating, Imaging, and Phenotyping Small Invertebrates and Vertebrates. Annu Rev Biomed Eng 2011; 13:185-217. [DOI: 10.1146/annurev-bioeng-071910-124703] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mehmet Fatih Yanik
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Christopher B. Rohde
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Carlos Pardo-Martin
- Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139;
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
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19
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Rohde CB, Yanik MF. Subcellular in vivo time-lapse imaging and optical manipulation of Caenorhabditis elegans in standard multiwell plates. Nat Commun 2011; 2:271. [PMID: 21468023 DOI: 10.1038/ncomms1266] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 03/07/2011] [Indexed: 01/19/2023] Open
Abstract
High-resolution in vivo time-lapse assays require repeated immobilization and imaging of whole animals. Here we report a technology for screening Caenorhabditis elegans at cellular resolution over its entire lifespan inside standard multiwell plates using repeated immobilization, imaging and optical manipulation. Our system does not use any fluidic or mechanical components, and can operate for tens of thousands of cycles without failure. It is also compatible with industrial high-throughput screening platforms and robotics, and it allows both chemical, and forward and reverse genetic screens. We used this technology to perform subcellular-resolution femtosecond laser microsurgery of single neurons in vivo, and to image the subsequent regeneration dynamics at subcellular resolution. Our single-neuron in vivo time-lapse analysis shows that neurite regrowth occurring over short time windows is significantly greater than that predicted by ensemble averaging over many animals.
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Affiliation(s)
- Christopher B Rohde
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Abstract
Neurons communicate with other cells via axons and dendrites, slender membrane extensions that contain pre- or post-synaptic specializations. If a neuron is damaged by injury or disease, it may regenerate. Cell-intrinsic and extrinsic factors influence the ability of a neuron to regenerate and restore function. Recently, the nematode C. elegans has emerged as an excellent model organism to identify genes and signaling pathways that influence the regeneration of neurons(1-6). The main way to initiate neuronal regeneration in C. elegans is laser-mediated cutting, or axotomy. During axotomy, a fluorescently-labeled neuronal process is severed using high-energy pulses. Initially, neuronal regeneration in C. elegans was examined using an amplified femtosecond laser(5). However, subsequent regeneration studies have shown that a conventional pulsed laser can be used to accurately sever neurons in vivo and elicit a similar regenerative response(1,3,7). We present a protocol for performing in vivo laser axotomy in the worm using a MicroPoint pulsed laser, a turnkey system that is readily available and that has been widely used for targeted cell ablation. We describe aligning the laser, mounting the worms, cutting specific neurons, and assessing subsequent regeneration. The system provides the ability to cut large numbers of neurons in multiple worms during one experiment. Thus, laser axotomy as described herein is an efficient system for initiating and analyzing the process of regeneration.
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Affiliation(s)
- Alexandra B Byrne
- Department of Genetics, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, USA
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21
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Gilleland CL, Rohde CB, Zeng F, Yanik MF. Microfluidic immobilization of physiologically active Caenorhabditis elegans. Nat Protoc 2010; 5:1888-902. [PMID: 21127483 DOI: 10.1038/nprot.2010.143] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We present a protocol for building and operating a microfluidic device for mechanical immobilization of Caenorhabditis elegans in its physiologically active state. The system can be used for in vivo imaging of dynamic cellular processes such as cell division and migration, degeneration, aging and regeneration, as well as for laser microsurgery, Ca2+ imaging and three-dimensional microscopy. The device linearly orients C. elegans, and then completely restrains its motion by pressing a flexible membrane against the animal. This technique does not involve any potentially harmful anesthetics, gases or cooling procedures. The system can be installed on any microscope and operated using only one syringe and one external valve, making it accessible to most laboratories. The device fabrication begins by patterning photoresist structures on silicon wafers, which are then used to mold features in elastomeric layers that are thermally bonded to form the device. The system can be assembled within 3 d.
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Affiliation(s)
- Cody L Gilleland
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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22
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Large-scale in vivo femtosecond laser neurosurgery screen reveals small-molecule enhancer of regeneration. Proc Natl Acad Sci U S A 2010; 107:18342-7. [PMID: 20937901 DOI: 10.1073/pnas.1005372107] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Discovery of molecular mechanisms and chemical compounds that enhance neuronal regeneration can lead to development of therapeutics to combat nervous system injuries and neurodegenerative diseases. By combining high-throughput microfluidics and femtosecond laser microsurgery, we demonstrate for the first time large-scale in vivo screens for identification of compounds that affect neurite regeneration. We performed thousands of microsurgeries at single-axon precision in the nematode Caenorhabditis elegans at a rate of 20 seconds per animal. Following surgeries, we exposed the animals to a hand-curated library of approximately one hundred small molecules and identified chemicals that significantly alter neurite regeneration. In particular, we found that the PKC kinase inhibitor staurosporine strongly modulates regeneration in a concentration- and neuronal type-specific manner. Two structurally unrelated PKC inhibitors produce similar effects. We further show that regeneration is significantly enhanced by the PKC activator prostratin.
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23
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Abstract
We demonstrate a high-throughput platform for cellular-resolution in vivo chemical and genetic screens on zebrafish larvae. The system automatically loads zebrafish from reservoirs or multiwell plates, and positions and rotates them for high-speed confocal imaging and laser manipulation of both superficial and deep organs within 19 s without damage. We performed small-scale test screening of retinal axon guidance mutants and neuronal regeneration assays in combination with femtosecond laser microsurgery.
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