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Sonmez UM, Frey N, LeDuc PR, Minden JS. Fly Me to the Micron: Microtechnologies for Drosophila Research. Annu Rev Biomed Eng 2024; 26:441-473. [PMID: 38959386 DOI: 10.1146/annurev-bioeng-050423-054647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Multicellular model organisms, such as Drosophila melanogaster (fruit fly), are frequently used in a myriad of biological research studies due to their biological significance and global standardization. However, traditional tools used in these studies generally require manual handling, subjective phenotyping, and bulk treatment of the organisms, resulting in laborious experimental protocols with limited accuracy. Advancements in microtechnology over the course of the last two decades have allowed researchers to develop automated, high-throughput, and multifunctional experimental tools that enable novel experimental paradigms that would not be possible otherwise. We discuss recent advances in microtechnological systems developed for small model organisms using D. melanogaster as an example. We critically analyze the state of the field by comparing the systems produced for different applications. Additionally, we suggest design guidelines, operational tips, and new research directions based on the technical and knowledge gaps in the literature. This review aims to foster interdisciplinary work by helping engineers to familiarize themselves with model organisms while presenting the most recent advances in microengineering strategies to biologists.
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Affiliation(s)
- Utku M Sonmez
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA;
- Current affiliation: Department of Neuroscience, Scripps Research, San Diego, California, USA
- Current affiliation: Department of NanoEngineering, University of California San Diego, La Jolla, California, USA
| | - Nolan Frey
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA;
| | - Philip R LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA;
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Jonathan S Minden
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA;
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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2
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Lee D, Yang K, Xie J. Advances in Nerve Injury Models on a Chip. Adv Biol (Weinh) 2023; 7:e2200227. [PMID: 36709421 DOI: 10.1002/adbi.202200227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 12/19/2022] [Indexed: 01/30/2023]
Abstract
Regeneration and functional recovery of the damaged nerve are challenging due to the need for effective therapeutic drugs, biomaterials, and approaches. The poor outcome of the treatment of nerve injury stems from the incomplete understanding of axonal biology and interactions between neurons and the surrounding environment, such as glial cells and extracellular matrix. Microfluidic devices, in combination with various injury techniques, have been applied to test biological hypotheses in nerve injury and nerve regeneration. The microfluidic devices provide multiple advantages over the in vitro cell culture on a petri dish and in vivo animal models because a specific part of the neuronal environment can be manipulated using physical and chemical interventions. In addition, single-cell behavior and interactions between neurons and glial cells can be visualized and quantified on microfluidic platforms. In this article, current in vitro nerve injury models on a chip that mimics in vivo axonal injuries and the regeneration process of axons are summarized. The microfluidic-based nerve injury models could enhance the understanding of the physiological and pathophysiological mechanisms of nerve tissues and simultaneously serve as powerful drug and biomaterial screening platforms.
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Affiliation(s)
- Donghee Lee
- Department of Surgery-Transplant and Mary and Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Kai Yang
- Department of Surgery-Plastic Surgery, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jingwei Xie
- Department of Surgery-Transplant and Mary and Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Department of Mechanical and Materials Engineering, College of Engineering, University of Nebraska Lincoln, Lincoln, NE, 68588, USA
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3
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Frey N, Sönmez UM, Minden J, LeDuc P. Microfluidics for understanding model organisms. Nat Commun 2022; 13:3195. [PMID: 35680898 PMCID: PMC9184607 DOI: 10.1038/s41467-022-30814-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 05/20/2022] [Indexed: 11/29/2022] Open
Abstract
New microfluidic systems for whole organism analysis and experimentation are catalyzing biological breakthroughs across many fields, from human health to fundamental biology principles. This perspective discusses recent microfluidic tools to study intact model organisms to demonstrate the tremendous potential for these integrated approaches now and into the future. We describe these microsystems' technical features and highlight the unique advantages for precise manipulation in areas including immobilization, automated alignment, sorting, sensory, mechanical and chemical stimulation, and genetic and thermal perturbation. Our aim is to familiarize technologically focused researchers with microfluidics applications in biology research, while providing biologists an entrée to advanced microengineering techniques for model organisms. Building small-scale tools for biology research eliminates the need for time-consuming methods and enables novel experimental paradigms. Here, the authors discuss microfluidics' potential for manipulating or stimulating model organisms and identify barriers to making these tools accessible.
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Affiliation(s)
- Nolan Frey
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Utku M Sönmez
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Jonathan Minden
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
| | - Philip LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Computation Biology, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
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4
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Zhang KS, Nadkarni AV, Paul R, Martin AM, Tang SKY. Microfluidic Surgery in Single Cells and Multicellular Systems. Chem Rev 2022; 122:7097-7141. [PMID: 35049287 DOI: 10.1021/acs.chemrev.1c00616] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Microscale surgery on single cells and small organisms has enabled major advances in fundamental biology and in engineering biological systems. Examples of applications range from wound healing and regeneration studies to the generation of hybridoma to produce monoclonal antibodies. Even today, these surgical operations are often performed manually, but they are labor intensive and lack reproducibility. Microfluidics has emerged as a powerful technology to control and manipulate cells and multicellular systems at the micro- and nanoscale with high precision. Here, we review the physical and chemical mechanisms of microscale surgery and the corresponding design principles, applications, and implementations in microfluidic systems. We consider four types of surgical operations: (1) sectioning, which splits a biological entity into multiple parts, (2) ablation, which destroys part of an entity, (3) biopsy, which extracts materials from within a living cell, and (4) fusion, which joins multiple entities into one. For each type of surgery, we summarize the motivating applications and the microfluidic devices developed. Throughout this review, we highlight existing challenges and opportunities. We hope that this review will inspire scientists and engineers to continue to explore and improve microfluidic surgical methods.
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Affiliation(s)
- Kevin S Zhang
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Ambika V Nadkarni
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States.,Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 94158, United States
| | - Rajorshi Paul
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Adrian M Martin
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Sindy K Y Tang
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
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5
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Medioni C, Ephrussi A, Besse F. Live-Imaging of Axonal Cargoes in Drosophila Brain Explants Using Confocal Microscopy. Methods Mol Biol 2022; 2417:19-28. [PMID: 35099788 DOI: 10.1007/978-1-0716-1916-2_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Live-imaging of axonal cargoes within central nervous system has been a long-lasting interest for neurobiologists as axonal transport plays critical roles in neuronal growth, function, and survival. Many kinds of cargoes are transported within axons, including synaptic vesicles and a variety of membrane-bound and membrane-less organelles. Imaging these cargoes at high spatial and temporal resolution, and within living brains, is technically very challenging. Here, we describe a quantitative method, based on customized mounting chambers, allowing live-imaging of axonal cargoes transported within the maturing brain of the fruit fly, Drosophila melanogaster. With this method, we could visualize in real time, using confocal microscopy, cargoes transported along axons. Our protocol is simple and easy to set up, as brains are mounted in our imaging chambers and ready to be imaged in about 1 h. Another advantage of our method is that it can be combined with pharmacological treatments or super-resolution microscopy.
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Affiliation(s)
| | - Anne Ephrussi
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
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6
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Russell McEvoy GM, Shogan H, Sové RJ, Fraser GM. Development and validation of a novel microfluidic device for the manipulation of skeletal muscle microvascular blood flow in vivo. Microcirculation 2021; 28:e12698. [PMID: 33817909 DOI: 10.1111/micc.12698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 03/10/2021] [Accepted: 03/22/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To develop and validate a novel liquid microfluidic approach to deliver drugs to microscale regions of tissue while simultaneously allowing for visualization and quantification of microvascular blood flow. METHODS Microfluidic devices were fabricated using soft lithographic techniques, molded in polydimethylsiloxane, and bound to a coverslip with a 600 × 300 μm micro-outlet. Sprague-Dawley rats, anesthetized with pentobarbital, were instrumented to monitor systemic parameters. The extensor digitorum longus muscle was dissected, externalized, and reflected across the device mounted on the stage of an inverted microscope. Doses (10-8 to 10-3 M) of adenosine triphosphate (ATP), acetylcholine, and phenylephrine (PE) were administered to the muscle via perfusion through the device. Microvascular blood flow directly overlying the micro-outlet was recorded at multiple focal depths. Red blood cell (RBC) velocity, supply rate, and hematocrit were measured from recordings. RESULTS ATP significantly increased RBC velocity and supply rate. Increasing concentrations of PE caused a decrease in RBC velocity and supply rate. Perfusion changes were restricted to areas directly overlying the micro-outlet and within 500 μm. CONCLUSIONS This novel microfluidic device allows for a controlled delivery of dissolved substances to constrained regions of microvasculature while simultaneously allowing for visualization and measurement of blood flow within discrete vessels and networks.
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Affiliation(s)
- Gaylene M Russell McEvoy
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Hamza Shogan
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Richard J Sové
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD, Canada
| | - Graham M Fraser
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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7
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Neuroscience Research using Small Animals on a Chip: From Nematodes to Zebrafish Larvae. BIOCHIP JOURNAL 2021. [DOI: 10.1007/s13206-021-00012-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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Abstract
Neuropeptides are important for regulating numerous neural functions and behaviors. Release of neuropeptides requires long-lasting, high levels of cytosolic Ca2+ However, the molecular regulation of neuropeptide release remains to be clarified. Recently, Stac3 was identified as a key regulator of L-type Ca2+ channels (CaChs) and excitation-contraction coupling in vertebrate skeletal muscles. There is a small family of stac genes in vertebrates with other members expressed by subsets of neurons in the central nervous system. The function of neural Stac proteins, however, is poorly understood. Drosophila melanogaster contain a single stac gene, Dstac, which is expressed by muscles and a subset of neurons, including neuropeptide-expressing motor neurons. Here, genetic manipulations, coupled with immunolabeling, Ca2+ imaging, electrophysiology, and behavioral analysis, revealed that Dstac regulates L-type CaChs (Dmca1D) in Drosophila motor neurons and this, in turn, controls the release of neuropeptides.
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9
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Hsu IU, Linsley JW, Reid LE, Hume RI, Leflein A, Kuwada JY. Dstac Regulates Excitation-Contraction Coupling in Drosophila Body Wall Muscles. Front Physiol 2020; 11:573723. [PMID: 33123029 PMCID: PMC7573238 DOI: 10.3389/fphys.2020.573723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/15/2020] [Indexed: 12/13/2022] Open
Abstract
Stac3 regulates excitation-contraction coupling (EC coupling) in vertebrate skeletal muscles by regulating the L-type voltage-gated calcium channel (Cav channel). Recently a stac-like gene, Dstac, was identified in Drosophila and found to be expressed by both a subset of neurons and muscles. Here, we show that Dstac and Dmca1D, the Drosophila L-type Cav channel, are necessary for normal locomotion by larvae. Immunolabeling with specific antibodies against Dstac and Dmca1D found that Dstac and Dmca1D are expressed by larval body-wall muscles. Furthermore, Ca2+ imaging of muscles of Dstac and Dmca1D deficient larvae found that Dstac and Dmca1D are required for excitation-contraction coupling. Finally, Dstac appears to be required for normal expression levels of Dmca1D in body-wall muscles. These results suggest that Dstac regulates Dmca1D during EC coupling and thus muscle contraction.
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Affiliation(s)
- I-Uen Hsu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Jeremy W Linsley
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
| | - Lilly E Reid
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Ari Leflein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - John Y Kuwada
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
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10
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Bostock MP, Prasad AR, Chaouni R, Yuen AC, Sousa-Nunes R, Amoyel M, Fernandes VM. An Immobilization Technique for Long-Term Time-Lapse Imaging of Explanted Drosophila Tissues. Front Cell Dev Biol 2020; 8:590094. [PMID: 33117817 PMCID: PMC7576353 DOI: 10.3389/fcell.2020.590094] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/15/2020] [Indexed: 01/19/2023] Open
Abstract
Time-lapse imaging is an essential tool to study dynamic biological processes that cannot be discerned from fixed samples alone. However, imaging cell- and tissue-level processes in intact animals poses numerous challenges if the organism is opaque and/or motile. Explant cultures of intact tissues circumvent some of these challenges, but sample drift remains a considerable obstacle. We employed a simple yet effective technique to immobilize tissues in medium-bathed agarose. We applied this technique to study multiple Drosophila tissues from first-instar larvae to adult stages in various orientations and with no evidence of anisotropic pressure or stress damage. Using this method, we were able to image fine features for up to 18 h and make novel observations. Specifically, we report that fibers characteristic of quiescent neuroblasts are inherited by their basal daughters during reactivation; that the lamina in the developing visual system is assembled roughly 2-3 columns at a time; that lamina glia positions are dynamic during development; and that the nuclear envelopes of adult testis cyst stem cells do not break down completely during mitosis. In all, we demonstrate that our protocol is well-suited for tissue immobilization and long-term live imaging, enabling new insights into tissue and cell dynamics in Drosophila.
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Affiliation(s)
- Matthew P. Bostock
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Anadika R. Prasad
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Rita Chaouni
- Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
| | - Alice C. Yuen
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Rita Sousa-Nunes
- Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
| | - Marc Amoyel
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Vilaiwan M. Fernandes
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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11
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Zhao Y, Demirci U, Chen Y, Chen P. Multiscale brain research on a microfluidic chip. LAB ON A CHIP 2020; 20:1531-1543. [PMID: 32150176 DOI: 10.1039/c9lc01010f] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
One major challenge in current brain research is generating an integrative understanding of the brain's functions and disorders from its multiscale neuronal architectures and connectivity. Thus, innovative neurotechnology tools are urgently required for deciphering the multiscale functional and structural organizations of the brain at hierarchical scales from the molecular to the organismal level by multiple brain research initiatives launched by the European Union, United States, Australia, Canada, China, Korea, and Japan. To meet this demand, microfluidic chips (μFCs) have rapidly evolved as a trans-scale neurotechnological toolset to enable multiscale studies of the brain due to their unique advantages in flexible microstructure design, multifunctional integration, accurate microenvironment control, and capacity for automatic sample processing. Here, we review the recent progress in applying innovative μFC-based neuro-technologies to promote multiscale brain research and uniquely focus on representative applications of μFCs to address challenges in brain research at each hierarchical level. We discuss the current trend of combinational applications of μFCs with other neuro- and biotechnologies, including optogenetics, brain organoids, and 3D bioprinting, for better multiscale brain research. In addition, we offer our insights into the existing outstanding questions at each hierarchical level of brain research that could potentially be addressed by advancing microfluidic techniques. This review will serve as a timely guide for bioengineers and neuroscientists to develop and apply μFC-based neuro-technologies for promoting basic and translational brain research.
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Affiliation(s)
- Yanan Zhao
- Department of Biomedical Engineering, Wuhan University School of Basic Medical Sciences, 115 Donghu Road, Wuhan 430071, China.
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12
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Bolus H, Crocker K, Boekhoff-Falk G, Chtarbanova S. Modeling Neurodegenerative Disorders in Drosophila melanogaster. Int J Mol Sci 2020; 21:E3055. [PMID: 32357532 PMCID: PMC7246467 DOI: 10.3390/ijms21093055] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/14/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022] Open
Abstract
Drosophila melanogaster provides a powerful genetic model system in which to investigate the molecular mechanisms underlying neurodegenerative diseases. In this review, we discuss recent progress in Drosophila modeling Alzheimer's Disease, Parkinson's Disease, Amyotrophic Lateral Sclerosis (ALS), Huntington's Disease, Ataxia Telangiectasia, and neurodegeneration related to mitochondrial dysfunction or traumatic brain injury. We close by discussing recent progress using Drosophila models of neural regeneration and how these are likely to provide critical insights into future treatments for neurodegenerative disorders.
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Affiliation(s)
- Harris Bolus
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA;
| | - Kassi Crocker
- Genetics Graduate Training Program, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI 53705, USA;
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI 53705, USA
| | - Grace Boekhoff-Falk
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI 53705, USA
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13
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Ghaemi R, Tong J, Gupta BP, Selvaganapathy PR. Microfluidic Device for Microinjection of Caenorhabditis elegans. MICROMACHINES 2020; 11:mi11030295. [PMID: 32168862 PMCID: PMC7143065 DOI: 10.3390/mi11030295] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/26/2022]
Abstract
Microinjection is an established and reliable method to deliver transgenic constructs and other reagents to specific locations in C. elegans worms. Specifically, microinjection of a desired DNA construct into the distal gonad is the most widely used method to generate germ-line transformation of C. elegans. Although, current C. elegans microinjection method is effective to produce transgenic worms, it requires expensive multi degree of freedom (DOF) micromanipulator, careful injection alignment procedure and skilled operator, all of which make it slow and not suitable for scaling to high throughput. A few microfabricated microinjectors have been developed recently to address these issues. However, none of them are capable of immobilizing a freely mobile animal such as C. elegans worm using a passive immobilization mechanism. Here, a microfluidic microinjector was developed to passively immobilize a freely mobile animal such as C. elegans and simultaneously perform microinjection by using a simple and fast mechanism for needle actuation. The entire process of the microinjection takes ~30 s which includes 10 s for worm loading and aligning, 5 s needle penetration, 5 s reagent injection and 5 s worm unloading. The device is suitable for high-throughput and can be potentially used for creating transgenic C. elegans.
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Affiliation(s)
- Reza Ghaemi
- Department of Mechanical Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada;
| | - Justin Tong
- Department of Biology, McMaster University, Hamilton, ON L8S 4L8, Canada; (J.T.); (B.P.G.)
| | - Bhagwati P. Gupta
- Department of Biology, McMaster University, Hamilton, ON L8S 4L8, Canada; (J.T.); (B.P.G.)
| | - P. Ravi Selvaganapathy
- Department of Mechanical Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada;
- Correspondence: ; Tel.: +1-905-525-9140 (ext. 27435)
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14
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Kakanj P, Eming SA, Partridge L, Leptin M. Long-term in vivo imaging of Drosophila larvae. Nat Protoc 2020; 15:1158-1187. [DOI: 10.1038/s41596-019-0282-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/09/2019] [Indexed: 02/07/2023]
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15
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Zabihihesari A, Hilliker AJ, Rezai P. Localized microinjection of intact Drosophila melanogaster larva to investigate the effect of serotonin on heart rate. LAB ON A CHIP 2020; 20:343-355. [PMID: 31828261 DOI: 10.1039/c9lc00963a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this paper, we present a novel hybrid microfluidic device for localized microinjection and heart monitoring of intact Drosophila melanogaster larvae at different developmental stages. Drosophila heart at the larval stage has been used as a model for cardiac disorder studies. However, previous pharmacological and toxicological cardiac studies are limited to dissected (semi-intact) Drosophila larvae which cannot be used for post-treatment studies. Challenges associated with microinjection of intact larvae include delicate handling of individual larvae, proper orientation for microneedle penetration, localized microinjection with controlled amount of chemicals into the hemolymph and reversible immobilization for post-injection phenotypic studies, all addressed by our microfluidic device. Larva loading and orientation were achieved by glass capillaries integrated into the PDMS microfluidic device. Side suction channels were used for immobilization prior to heart activity recording. Localized microinjection was achieved with a one degree-of-freedom microneedle and a custom-made pressure driven reagent delivery system, without any adverse effect on heart rate and animal viability. Precision in localized injection into the body cavity close to the heart chamber or the fat body was demonstrated with our microfluidic device. A MATLAB-based heartbeat quantification technique was used to investigate the dose-dependent effect of serotonin (5-hydroxytryptamine), a neurotransmitter, on the heart rate of intact Drosophila larvae, for the first time. Injection of 40 nL serotonin with ≥0.01 mM concentration significantly increased the heart rate of 3rd instar larvae by 21 ± 7% (SEM). Injection of 5 nL serotonin with a concentration of 0.01 mM significantly increased the heart rate of 2nd instar larvae by 12 ± 3% (SEM). The proposed microfluidic injection and heartbeat monitoring technique can be used for dye angiography and hemolymph circulation studies as well as screening intravenous drugs in vivo using the whole-animal Drosophila melanogaster.
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Affiliation(s)
- Alireza Zabihihesari
- Department of Mechanical Engineering, York University, BRG 433B, 4700 Keele St, Toronto, ON M3J 1P3, Canada.
| | | | - Pouya Rezai
- Department of Mechanical Engineering, York University, BRG 433B, 4700 Keele St, Toronto, ON M3J 1P3, Canada.
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16
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Zabihihesari A, Hilliker AJ, Rezai P. Fly-on-a-Chip: Microfluidics for Drosophila melanogaster Studies. Integr Biol (Camb) 2020; 11:425-443. [DOI: 10.1093/intbio/zyz037] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/21/2019] [Accepted: 10/26/2019] [Indexed: 12/16/2022]
Abstract
Abstract
The fruit fly or Drosophila melanogaster has been used as a promising model organism in genetics, developmental and behavioral studies as well as in the fields of neuroscience, pharmacology, and toxicology. Not only all the developmental stages of Drosophila, including embryonic, larval, and adulthood stages, have been used in experimental in vivo biology, but also the organs, tissues, and cells extracted from this model have found applications in in vitro assays. However, the manual manipulation, cellular investigation and behavioral phenotyping techniques utilized in conventional Drosophila-based in vivo and in vitro assays are mostly time-consuming, labor-intensive, and low in throughput. Moreover, stimulation of the organism with external biological, chemical, or physical signals requires precision in signal delivery, while quantification of neural and behavioral phenotypes necessitates optical and physical accessibility to Drosophila. Recently, microfluidic and lab-on-a-chip devices have emerged as powerful tools to overcome these challenges. This review paper demonstrates the role of microfluidic technology in Drosophila studies with a focus on both in vivo and in vitro investigations. The reviewed microfluidic devices are categorized based on their applications to various stages of Drosophila development. We have emphasized technologies that were utilized for tissue- and behavior-based investigations. Furthermore, the challenges and future directions in Drosophila-on-a-chip research, and its integration with other advanced technologies, will be discussed.
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Affiliation(s)
| | | | - Pouya Rezai
- Department of Mechanical Engineering, York University, Toronto, ON, Canada
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17
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Merrin J. Frontiers in Microfluidics, a Teaching Resource Review. Bioengineering (Basel) 2019; 6:E109. [PMID: 31816954 PMCID: PMC6955790 DOI: 10.3390/bioengineering6040109] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 02/02/2023] Open
Abstract
This is a literature teaching resource review for biologically inspired microfluidics courses or exploring the diverse applications of microfluidics. The structure is around key papers and model organisms. While courses gradually change over time, a focus remains on understanding how microfluidics has developed as well as what it can and cannot do for researchers. As a primary starting point, we cover micro-fluid mechanics principles and microfabrication of devices. A variety of applications are discussed using model prokaryotic and eukaryotic organisms from the set of bacteria (Escherichia coli), trypanosomes (Trypanosoma brucei), yeast (Saccharomyces cerevisiae), slime molds (Physarum polycephalum), worms (Caenorhabditis elegans), flies (Drosophila melangoster), plants (Arabidopsis thaliana), and mouse immune cells (Mus musculus). Other engineering and biochemical methods discussed include biomimetics, organ on a chip, inkjet, droplet microfluidics, biotic games, and diagnostics. While we have not yet reached the end-all lab on a chip, microfluidics can still be used effectively for specific applications.
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Affiliation(s)
- Jack Merrin
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
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18
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Guo W, Stoklund Dittlau K, Van Den Bosch L. Axonal transport defects and neurodegeneration: Molecular mechanisms and therapeutic implications. Semin Cell Dev Biol 2019; 99:133-150. [PMID: 31542222 DOI: 10.1016/j.semcdb.2019.07.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 06/22/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022]
Abstract
Because of the extremely polarized morphology, the proper functioning of neurons largely relies on the efficient cargo transport along the axon. Axonal transport defects have been reported in multiple neurodegenerative diseases as an early pathological feature. The discovery of mutations in human genes involved in the transport machinery provide a direct causative relationship between axonal transport defects and neurodegeneration. Here, we summarize the current genetic findings related to axonal transport in neurodegenerative diseases, and we discuss the relationship between axonal transport defects and other pathological changes observed in neurodegeneration. In addition, we summarize the therapeutic approaches targeting the axonal transport machinery in studies of neurodegenerative diseases. Finally, we review the technical advances in tracking axonal transport both in vivo and in vitro.
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Affiliation(s)
- Wenting Guo
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium; KU Leuven-Stem Cell Institute (SCIL), Leuven, Belgium
| | - Katarina Stoklund Dittlau
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
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19
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Cevik D, Acker M, Arefi P, Ghaemi R, Zhang J, Selvaganapathy PR, Dworkin I, Jacobs JR. Chloroform and desflurane immobilization with recovery of viable Drosophila larvae for confocal imaging. JOURNAL OF INSECT PHYSIOLOGY 2019; 117:103900. [PMID: 31202852 DOI: 10.1016/j.jinsphys.2019.103900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 06/03/2019] [Accepted: 06/12/2019] [Indexed: 06/09/2023]
Abstract
Imaging of living, intact Drosophila larvae is challenged if normal bodily function must be observed or when healthy larvae must be recovered for subsequent studies. Here, we describe a simple and short protocol that employs transient airborne chloroform or desflurane (1,2,2,2-tetrafluoroethyl difluoromethyl ether) to efficiently immobilize larvae without the use of manipulation devices, vaporizers or imaging chambers. This non-lethal method allows the use of anesthetics while allowing tracking of individual Drosophila into adulthood for follow-up experiments. At dosages sufficient to immobilize larvae, Desflurane, but not chloroform reduced the central nervous system response to auditory stimulus. Desflurane doses were sufficient to arrest the heart, however significant rapid recovery was observed. With our method, chloroform provided more rapid anesthesia but slower recovery than Desflurane. Without specialized hardware, this technique allows for repeated imaging of living Drosophila larvae.
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Affiliation(s)
- Duygu Cevik
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Meryl Acker
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Pouya Arefi
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Reza Ghaemi
- Department of Mechanical Engineering, McMaster University, Hamilton L8S 4L7, Canada
| | - Jimmy Zhang
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | | | - Ian Dworkin
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada; Department of Mechanical Engineering, McMaster University, Hamilton L8S 4L7, Canada
| | - J Roger Jacobs
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada.
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20
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Chu CC, Zhao SZ. Pathophysiological Role and Drug Modulation of Calcium Transport in Ocular Surface Cells. Curr Med Chem 2019; 27:5078-5091. [PMID: 31237195 DOI: 10.2174/0929867326666190619114848] [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: 12/03/2018] [Revised: 04/28/2019] [Accepted: 05/21/2019] [Indexed: 11/22/2022]
Abstract
The ocular surface structure and extraocular accessory organs constitute the ocular surface system, which includes the cornea, conjunctiva, eyelids, lacrimal organs, and lacrimal passages. This system is composed of, and stabilized by, the corneal epithelium, conjunctival cells, conjunctival goblet cells, lacrimal acinar cells and Tenon's fibroblasts, all of which maintain the healthy eyeball surface system. Ocular surface diseases are commonly referred to corneal and conjunctival disease and external ocular disease, resulting from damage to the ocular surface structure. A growing body of evidence has indicated that abnormal activation of the KCa3.1 channel and Ca2+/ calmodulin-dependent kinase initiates ocular injury. Signaling pathways downstream of the irregular Ca2+ influx induce cell progression and migration, and impair tight junctions, epithelial transport and secretory function. In this overview, we summarize the current knowledge regarding ocular surface disease in terms of physical and pathological alteration of the ocular system. We dissect in-depth, the mechanisms underlying disease progression, and we describe the current calcium transport therapeutics and the obstacles that remain to be solved. Finally, we summarize how to integrate the research results into clinical practice in the future.
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Affiliation(s)
- Chen-Chen Chu
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin, 300384, China
| | - Shao-Zhen Zhao
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin, 300384, China
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21
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Wu Q, Kumar N, Velagala V, Zartman JJ. Tools to reverse-engineer multicellular systems: case studies using the fruit fly. J Biol Eng 2019; 13:33. [PMID: 31049075 PMCID: PMC6480878 DOI: 10.1186/s13036-019-0161-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/07/2019] [Indexed: 01/08/2023] Open
Abstract
Reverse-engineering how complex multicellular systems develop and function is a grand challenge for systems bioengineers. This challenge has motivated the creation of a suite of bioengineering tools to develop increasingly quantitative descriptions of multicellular systems. Here, we survey a selection of these tools including microfluidic devices, imaging and computer vision techniques. We provide a selected overview of the emerging cross-talk between engineering methods and quantitative investigations within developmental biology. In particular, the review highlights selected recent examples from the Drosophila system, an excellent platform for understanding the interplay between genetics and biophysics. In sum, the integrative approaches that combine multiple advances in these fields are increasingly necessary to enable a deeper understanding of how to analyze both natural and synthetic multicellular systems.
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Affiliation(s)
- Qinfeng Wu
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Nilay Kumar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Vijay Velagala
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Jeremiah J. Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
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22
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Vaadia RD, Li W, Voleti V, Singhania A, Hillman EMC, Grueber WB. Characterization of Proprioceptive System Dynamics in Behaving Drosophila Larvae Using High-Speed Volumetric Microscopy. Curr Biol 2019; 29:935-944.e4. [PMID: 30853438 PMCID: PMC6624193 DOI: 10.1016/j.cub.2019.01.060] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/16/2019] [Accepted: 01/24/2019] [Indexed: 01/09/2023]
Abstract
Proprioceptors provide feedback about body position that is essential for coordinated movement. Proprioceptive sensing of the position of rigid joints has been described in detail in several systems; however, it is not known how animals with a flexible skeleton encode their body positions. Understanding how diverse larval body positions are dynamically encoded requires knowledge of proprioceptor activity patterns in vivo during natural movement. Here we used high-speed volumetric swept confocally aligned planar excitation (SCAPE) microscopy in crawling Drosophila larvae to simultaneously track the position, deformation, and intracellular calcium activity of their multidendritic proprioceptors. Most proprioceptive neurons were found to activate during segment contraction, although one subtype was activated by extension. During cycles of segment contraction and extension, different proprioceptor types exhibited sequential activity, providing a continuum of position encoding during all phases of crawling. This sequential activity was related to the dynamics of each neuron’s terminal processes, and could endow each proprioceptor with a specific role in monitoring different aspects of body-wall deformation. We demonstrate this deformation encoding both during progression of contraction waves during locomotion as well as during less stereotyped, asymmetric exploration behavior. Our results provide powerful new insights into the body-wide neuronal dynamics of the proprioceptive system in crawling Drosophila, and demonstrate the utility of our SCAPE microscopy approach for characterization of neural encoding throughout the nervous system of a freely behaving animal. Vaadia, Li et al. use high-speed 3D SCAPE microscopy to monitor proprioceptor morphology and calcium dynamics in behaving Drosophila larvae. Neural activity is coincident with dendritic deformations, and different subtypes exhibit sequential onset of activity during crawling. Analysis during non-stereotyped exploration shows proprioceptor versatility.
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Affiliation(s)
- Rebecca D Vaadia
- Grueber Laboratory, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Neuroscience, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Wenze Li
- Laboratory for Functional Optical Imaging, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Venkatakaushik Voleti
- Laboratory for Functional Optical Imaging, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Aditi Singhania
- Grueber Laboratory, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA; Department of Radiology, Columbia University Irving Medical Center, New York, NY 10032, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10032, USA.
| | - Wesley B Grueber
- Grueber Laboratory, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Neuroscience, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA.
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23
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Levis M, Kumar N, Apakian E, Moreno C, Hernandez U, Olivares A, Ontiveros F, Zartman JJ. Microfluidics on the fly: Inexpensive rapid fabrication of thermally laminated microfluidic devices for live imaging and multimodal perturbations of multicellular systems. BIOMICROFLUIDICS 2019; 13:024111. [PMID: 31065310 PMCID: PMC6486393 DOI: 10.1063/1.5086671] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/08/2019] [Indexed: 05/06/2023]
Abstract
Microfluidic devices provide a platform for analyzing both natural and synthetic multicellular systems. Currently, substantial capital investment and expertise are required for creating microfluidic devices using standard soft-lithography. These requirements present barriers to entry for many nontraditional users of microfluidics, including developmental biology laboratories. Therefore, fabrication methodologies that enable rapid device iteration and work "out-of-the-box" can accelerate the integration of microfluidics with developmental biology. Here, we have created and characterized low-cost hybrid polyethylene terephthalate laminate (PETL) microfluidic devices that are suitable for cell and micro-organ culture assays. These devices were validated with mammalian cell lines and the Drosophila wing imaginal disc as a model micro-organ. First, we developed and tested PETLs that are compatible with both long-term cultures and high-resolution imaging of cells and organs. Further, we achieved spatiotemporal control of chemical gradients across the wing discs with a multilayered microfluidic device. Finally, we created a multilayered device that enables controllable mechanical loading of micro-organs. This mechanical actuation assay was used to characterize the response of larval wing discs at different developmental stages. Interestingly, increased deformation of the older wing discs for the same mechanical loading suggests that the compliance of the organ is increased in preparation for subsequent morphogenesis. Together, these results demonstrate the applicability of hybrid PETL devices for biochemical and mechanobiology studies on micro-organs and provide new insights into the mechanics of organ development.
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Affiliation(s)
- Megan Levis
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Nilay Kumar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Emily Apakian
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Cesar Moreno
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Ulises Hernandez
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Ana Olivares
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Fernando Ontiveros
- Biology Department, St. John Fisher College, Rochester, New York 14618, USA
| | - Jeremiah J. Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
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24
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Karagyozov D, Mihovilovic Skanata M, Lesar A, Gershow M. Recording Neural Activity in Unrestrained Animals with Three-Dimensional Tracking Two-Photon Microscopy. Cell Rep 2018; 25:1371-1383.e10. [PMID: 30380425 PMCID: PMC6287944 DOI: 10.1016/j.celrep.2018.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 08/07/2018] [Accepted: 10/02/2018] [Indexed: 11/25/2022] Open
Abstract
Optical recordings of neural activity in behaving animals can reveal the neural correlates of decision making, but brain motion, which often accompanies behavior, compromises these measurements. Two-photon point-scanning microscopy is especially sensitive to motion artifacts, and two-photon recording of activity has required rigid coupling between the brain and microscope. We developed a two-photon tracking microscope with extremely low-latency (360 μs) feedback implemented in hardware. This microscope can maintain continuous focus on neurons moving with velocities of 3 mm/s and accelerations of 1 m/s2 both in-plane and axially. We recorded calcium dynamics of motor neurons and inter-neurons in unrestrained freely behaving fruit fly larvae, correlating neural activity with stimulus presentations and behavioral outputs, and we measured light-induced depolarization of a visual interneuron in a moving animal using a genetically encoded voltage indicator. Our technique can be extended to stabilize recordings in a variety of moving substrates.
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Affiliation(s)
| | | | - Amanda Lesar
- Department of Physics, New York University, New York, NY, USA
| | - Marc Gershow
- Department of Physics, New York University, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA; Neuroscience Institute, New York University, New York, NY, USA.
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25
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Reuveny A, Shnayder M, Lorber D, Wang S, Volk T. Ma2/d promotes myonuclear positioning and association with the sarcoplasmic reticulum. Development 2018; 145:dev.159558. [PMID: 30093550 DOI: 10.1242/dev.159558] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 07/24/2018] [Indexed: 12/24/2022]
Abstract
The cytoplasm of striated myofibers contains a large number of membrane organelles, including sarcoplasmic reticulum (SR), T-tubules and the nuclear membrane. These organelles maintain a characteristic juxtaposition that appears to be essential for efficient inter-membranous exchange of RNA, proteins and ions. We found that the membrane-associated Muscle-specific α2/δ (Ma2/d) subunit of the Ca2+ channel complex localizes to the SR and T-tubules, and accumulates at the myonuclear surfaces. Furthermore, Ma2/d mutant larval muscles exhibit nuclear positioning defects, disruption of the nuclear-SR juxtapositioning, as well as impaired larval locomotion. Ma2/d localization at the nuclear membrane depends on the proper function of the nesprin ortholog Msp300 and the BAR domain protein Amphiphysin (Amph). Importantly, live imaging of muscle contraction in intact Drosophila larvae indicated altered distribution of Sarco/Endoplamic Reticulum Ca2+-ATPase (SERCA) around the myonuclei of Ma2/d mutant larvae. Co-immunoprecipitation analysis supports association between Ma2/d and Amph, and indirectly with Msp300. We therefore suggest that Ma2/d, in association with Msp300 and Amph, mediates interactions between the SR and the nuclear membrane.
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Affiliation(s)
- Adriana Reuveny
- Department of Molecular Genetics, Weizmann Institute, Rehovot 76100, Israel
| | - Marina Shnayder
- Department of Molecular Genetics, Weizmann Institute, Rehovot 76100, Israel
| | - Dana Lorber
- Department of Molecular Genetics, Weizmann Institute, Rehovot 76100, Israel
| | - Shuoshuo Wang
- Department of Molecular Genetics, Weizmann Institute, Rehovot 76100, Israel
| | - Talila Volk
- Department of Molecular Genetics, Weizmann Institute, Rehovot 76100, Israel
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26
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Kim AA, Nekimken AL, Fechner S, O'Brien LE, Pruitt BL. Microfluidics for mechanobiology of model organisms. Methods Cell Biol 2018; 146:217-259. [PMID: 30037463 PMCID: PMC6418080 DOI: 10.1016/bs.mcb.2018.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mechanical stimuli play a critical role in organ development, tissue homeostasis, and disease. Understanding how mechanical signals are processed in multicellular model systems is critical for connecting cellular processes to tissue- and organism-level responses. However, progress in the field that studies these phenomena, mechanobiology, has been limited by lack of appropriate experimental techniques for applying repeatable mechanical stimuli to intact organs and model organisms. Microfluidic platforms, a subgroup of microsystems that use liquid flow for manipulation of objects, are a promising tool for studying mechanobiology of small model organisms due to their size scale and ease of customization. In this work, we describe design considerations involved in developing a microfluidic device for studying mechanobiology. Then, focusing on worms, fruit flies, and zebrafish, we review current microfluidic platforms for mechanobiology of multicellular model organisms and their tissues and highlight research opportunities in this developing field.
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Affiliation(s)
- Anna A Kim
- University of California, Santa Barbara, CA, United States; Uppsala University, Uppsala, Sweden; Stanford University, Stanford, CA, United States
| | | | | | | | - Beth L Pruitt
- University of California, Santa Barbara, CA, United States; Stanford University, Stanford, CA, United States.
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27
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Shrirao AB, Kung FH, Omelchenko A, Schloss RS, Boustany NN, Zahn JD, Yarmush ML, Firestein BL. Microfluidic platforms for the study of neuronal injury in vitro. Biotechnol Bioeng 2018; 115:815-830. [PMID: 29251352 DOI: 10.1002/bit.26519] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/11/2017] [Accepted: 12/15/2017] [Indexed: 12/27/2022]
Abstract
Traumatic brain injury (TBI) affects 5.3 million people in the United States, and there are 12,500 new cases of spinal cord injury (SCI) every year. There is yet a significant need for in vitro models of TBI and SCI in order to understand the biological mechanisms underlying central nervous system (CNS) injury and to identify and test therapeutics to aid in recovery from neuronal injuries. While TBI or SCI studies have been aided with traditional in vivo and in vitro models, the innate limitations in specificity of injury, isolation of neuronal regions, and reproducibility of these models can decrease their usefulness in examining the neurobiology of injury. Microfluidic devices provide several advantages over traditional methods by allowing researchers to (1) examine the effect of injury on specific neural components, (2) fluidically isolate neuronal regions to examine specific effects on subcellular components, and (3) reproducibly create a variety of injuries to model TBI and SCI. These microfluidic devices are adaptable for modeling a wide range of injuries, and in this review, we will examine different methodologies and models recently utilized to examine neuronal injury. Specifically, we will examine vacuum-assisted axotomy, physical injury, chemical injury, and laser-based axotomy. Finally, we will discuss the benefits and downsides to each type of injury model and discuss how researchers can use these parameters to pick a particular microfluidic device to model CNS injury.
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Affiliation(s)
- Anil B Shrirao
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Frank H Kung
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
| | - Anton Omelchenko
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
| | - Rene S Schloss
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Nada N Boustany
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Jeffrey D Zahn
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Martin L Yarmush
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
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28
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Miniaturized Sensors and Actuators for Biological Studies on Small Model Organisms of Disease. ENERGY, ENVIRONMENT, AND SUSTAINABILITY 2018. [DOI: 10.1007/978-981-10-7751-7_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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29
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Iacobucci GJ, Gunawardena S. Ethanol stimulates the in vivo axonal movement of neuropeptide dense-core vesicles in Drosophila motor neurons. J Neurochem 2017; 144:466-482. [PMID: 28960313 DOI: 10.1111/jnc.14230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 09/10/2017] [Accepted: 09/18/2017] [Indexed: 01/01/2023]
Abstract
Proper neuronal function requires essential biological cargoes to be packaged within membranous vesicles and transported, intracellularly, through the extensive outgrowth of axonal and dendritic fibers. The precise spatiotemporal movement of these cargoes is vital for neuronal survival and, thus, is highly regulated. In this study we test how the axonal movement of a neuropeptide-containing dense-core vesicle (DCV) responds to alcohol stressors. We found that ethanol induces a strong anterograde bias in vesicle movement. Low doses of ethanol stimulate the anterograde movement of neuropeptide-DCV while high doses inhibit bi-directional movement. This process required the presence of functional kinesin-1 motors as reduction in kinesin prevented the ethanol-induced stimulation of the anterograde movement of neuropeptide-DCV. Furthermore, expression of inactive glycogen synthase kinase 3 (GSK-3β) also prevented ethanol-induced stimulation of neuropeptide-DCV movement, similar to pharmacological inhibition of GSK-3β with lithium. Conversely, inhibition of PI3K/AKT signaling with wortmannin led to a partial prevention of ethanol-stimulated transport of neuropeptide-DCV. Taken together, we conclude that GSK-3β signaling mediates the stimulatory effects of ethanol. Therefore, our study provides new insight into the physiological response of the axonal movement of neuropeptide-DCV to exogenous stressors. Cover Image for this Issue: doi: 10.1111/jnc.14165.
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Affiliation(s)
- Gary J Iacobucci
- Department of Biological Sciences, the State University of New York at Buffalo, Buffalo, New York, USA
| | - Shermali Gunawardena
- Department of Biological Sciences, the State University of New York at Buffalo, Buffalo, New York, USA
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30
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Li J, Zhang YV, Asghari Adib E, Stanchev DT, Xiong X, Klinedinst S, Soppina P, Jahn TR, Hume RI, Rasse TM, Collins CA. Restraint of presynaptic protein levels by Wnd/DLK signaling mediates synaptic defects associated with the kinesin-3 motor Unc-104. eLife 2017; 6:e24271. [PMID: 28925357 PMCID: PMC5605197 DOI: 10.7554/elife.24271] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 08/11/2017] [Indexed: 12/19/2022] Open
Abstract
The kinesin-3 family member Unc-104/KIF1A is required for axonal transport of many presynaptic components to synapses, and mutation of this gene results in synaptic dysfunction in mice, flies and worms. Our studies at the Drosophila neuromuscular junction indicate that many synaptic defects in unc-104-null mutants are mediated independently of Unc-104's transport function, via the Wallenda (Wnd)/DLK MAP kinase axonal damage signaling pathway. Wnd signaling becomes activated when Unc-104's function is disrupted, and leads to impairment of synaptic structure and function by restraining the expression level of active zone (AZ) and synaptic vesicle (SV) components. This action concomitantly suppresses the buildup of synaptic proteins in neuronal cell bodies, hence may play an adaptive role to stresses that impair axonal transport. Wnd signaling also becomes activated when pre-synaptic proteins are over-expressed, suggesting the existence of a feedback circuit to match synaptic protein levels to the transport capacity of the axon.
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Affiliation(s)
- Jiaxing Li
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Yao V Zhang
- Junior Research Group Synaptic PlasticityHertie-Institute for Clinical Brain Research, University of TübingenTübingenGermany
- Graduate School of Cellular and Molecular NeuroscienceUniversity of TübingenTübingenGermany
| | - Elham Asghari Adib
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Doychin T Stanchev
- Junior Research Group Synaptic PlasticityHertie-Institute for Clinical Brain Research, University of TübingenTübingenGermany
- Graduate School of Cellular and Molecular NeuroscienceUniversity of TübingenTübingenGermany
| | - Xin Xiong
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Susan Klinedinst
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Pushpanjali Soppina
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Thomas Robert Jahn
- CHS Research Group Proteostasis in Neurodegenerative DiseaseDKFZ Deutsches KrebsforschungszentrumHeidelbergGermany
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Tobias M Rasse
- Junior Research Group Synaptic PlasticityHertie-Institute for Clinical Brain Research, University of TübingenTübingenGermany
- CHS Research Group Proteostasis in Neurodegenerative DiseaseDKFZ Deutsches KrebsforschungszentrumHeidelbergGermany
| | - Catherine A Collins
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
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31
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Narciso CE, Contento NM, Storey TJ, Hoelzle DJ, Zartman JJ. Release of Applied Mechanical Loading Stimulates Intercellular Calcium Waves in Drosophila Wing Discs. Biophys J 2017; 113:491-501. [PMID: 28746859 PMCID: PMC5529297 DOI: 10.1016/j.bpj.2017.05.051] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/15/2017] [Accepted: 05/17/2017] [Indexed: 01/14/2023] Open
Abstract
Mechanical forces are critical but poorly understood inputs for organogenesis and wound healing. Calcium ions (Ca2+) are critical second messengers in cells for integrating environmental and mechanical cues, but the regulation of Ca2+ signaling is poorly understood in developing epithelial tissues. Here we report a chip-based regulated environment for microorgans that enables systematic investigations of the crosstalk between an organ's mechanical stress environment and biochemical signaling under genetic and chemical perturbations. This method enabled us to define the essential conditions for generating organ-scale intercellular Ca2+ waves in Drosophila wing discs that are also observed in vivo during organ development. We discovered that mechanically induced intercellular Ca2+ waves require fly extract growth serum as a chemical stimulus. Using the chip-based regulated environment for microorgans, we demonstrate that not the initial application but instead the release of mechanical loading is sufficient, but not necessary, to initiate intercellular Ca2+ waves. The Ca2+ response depends on the prestress intercellular Ca2+ activity and not on the magnitude or duration of the mechanical stimulation applied. Mechanically induced intercellular Ca2+ waves rely on IP3R-mediated Ca2+-induced Ca2+ release and propagation through gap junctions. Thus, intercellular Ca2+ waves in developing epithelia may be a consequence of stress dissipation during organ growth.
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Affiliation(s)
- Cody E Narciso
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Nicholas M Contento
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Thomas J Storey
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana
| | - David J Hoelzle
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana.
| | - Jeremiah J Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana.
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32
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Regeneration of synapses in the olfactory pathway of locusts after antennal deafferentation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:867-877. [PMID: 28685185 DOI: 10.1007/s00359-017-1199-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 12/31/2022]
Abstract
The olfactory pathway of the locust is capable of fast and precise regeneration on an anatomical level. Following deafferentation of the antenna either of young adult locusts, or of fifth instar nymphs, severed olfactory receptor neurons (ORNs) reinnervate the antennal lobe (AL) and arborize in AL microglomeruli. In the present study we tested whether these regenerated fibers establish functional synapses again. Intracellular recordings from AL projection neurons revealed that the first few odor stimulus evoked postsynaptic responses from regenerated ORNs from day 4-7 post crush on. On average, synaptic connections of regenerated afferents appeared faster in younger locusts operated as fifth instar nymphs than in adults. The proportions of response categories (excitatory vs. inhibitory) changed during regeneration, but were back to normal within 21 days. Odor-evoked oscillating extracellular local field potentials (LFP) were recorded in the mushroom body. These responses, absent after antennal nerve crush, reappeared, in a few animals as soon as 4 days post crush. Odor-induced oscillation patterns were restored within 7 days post crush. Both intra- and extracellular recordings indicate the capability of the locust olfactory system to re-establish synaptic contacts in the antennal lobe after antennal nerve lesion.
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33
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Chaudhury AR, Insolera R, Hwang RD, Fridell YW, Collins C, Chronis N. On chip cryo-anesthesia of Drosophila larvae for high resolution in vivo imaging applications. LAB ON A CHIP 2017; 17:2303-2322. [PMID: 28613308 PMCID: PMC5559736 DOI: 10.1039/c7lc00345e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We present a microfluidic chip for immobilizing Drosophila melanogaster larvae for high resolution in vivo imaging. The chip creates a low-temperature micro-environment that anaesthetizes and immobilizes the larva in under 3 minutes. We characterized the temperature distribution within the chip and analyzed the resulting larval body movement using high resolution fluorescence imaging. Our results indicate that the proposed method minimizes submicron movements of internal organs and tissue without affecting the larva physiology. It can be used to continuously immobilize larvae for short periods of time (minutes) or for longer periods (several hours) if used intermittently. The same chip can be used to accommodate and immobilize arvae across all developmental stages (1st instar to late 3rd instar), and loading larvae onto the chip does not require any specialized skills. To demonstrate the usability of the chip, we observed mitochondrial trafficking in neurons from the cell bodies to the axon terminals along with mitochondrial fusion and neuro-synaptic growth through time in intact larvae. Besides studying sub-cellular processes and cellular development, we envision the use of on chip cryo-anesthesia in a wide variety of biological in vivo imaging applications, including observing organ development of the salivary glands, fat bodies and body-wall muscles.
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Affiliation(s)
- Amrita Ray Chaudhury
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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34
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Haring AP, Sontheimer H, Johnson BN. Microphysiological Human Brain and Neural Systems-on-a-Chip: Potential Alternatives to Small Animal Models and Emerging Platforms for Drug Discovery and Personalized Medicine. Stem Cell Rev Rep 2017; 13:381-406. [PMID: 28488234 PMCID: PMC5534264 DOI: 10.1007/s12015-017-9738-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Translational challenges associated with reductionist modeling approaches, as well as ethical concerns and economic implications of small animal testing, drive the need for developing microphysiological neural systems for modeling human neurological diseases, disorders, and injuries. Here, we provide a comprehensive review of microphysiological brain and neural systems-on-a-chip (NSCs) for modeling higher order trajectories in the human nervous system. Societal, economic, and national security impacts of neurological diseases, disorders, and injuries are highlighted to identify critical NSC application spaces. Hierarchical design and manufacturing of NSCs are discussed with distinction for surface- and bulk-based systems. Three broad NSC classes are identified and reviewed: microfluidic NSCs, compartmentalized NSCs, and hydrogel NSCs. Emerging areas and future directions are highlighted, including the application of 3D printing to design and manufacturing of next-generation NSCs, the use of stem cells for constructing patient-specific NSCs, and the application of human NSCs to 'personalized neurology'. Technical hurdles and remaining challenges are discussed. This review identifies the state-of-the-art design methodologies, manufacturing approaches, and performance capabilities of NSCs. This work suggests NSCs appear poised to revolutionize the modeling of human neurological diseases, disorders, and injuries.
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Affiliation(s)
- Alexander P Haring
- Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Harald Sontheimer
- Glial Biology in Health, Disease, and Cancer Center, Virginia Tech Carilion Research Institute, Roanoke, VA, 24016, USA
- School of Neuroscience, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Blake N Johnson
- Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA.
- School of Neuroscience, Virginia Tech, Blacksburg, VA, 24061, USA.
- Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
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Abstract
Live imaging provides the ability to continuously track dynamic cellular and developmental processes in real time. Drosophila larval imaginal discs have been used to study many biological processes, such as cell proliferation, differentiation, growth, migration, apoptosis, competition, cell-cell signaling, and compartmental boundary formation. However, methods for the long-term ex vivo culture and live imaging of the imaginal discs have not been satisfactory, despite many efforts. Recently, we developed a method for the long-term ex vivo culture and live imaging of imaginal discs for up to 18 h. In addition to using a high insulin concentration in the culture medium, a low-melting agarose was also used to embed the disc to prevent it from drifting during the imaging period. This report uses the eye-antennal discs as an example. Photoreceptor R3/4-specific mδ0.5-Ga4 expression was followed to demonstrate that photoreceptor differentiation and ommatidial rotation can be observed during a 10 h live imaging period. This is a detailed protocol describing this simple method.
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Affiliation(s)
- Chia-Kang Tsao
- Institute of Genomic Sciences, National Yang-Ming University; Institute of Molecular Biology, Academia Sinica
| | - Hui-Yu Ku
- Institute of Genomic Sciences, National Yang-Ming University; Institute of Molecular Biology, Academia Sinica
| | - Y Henry Sun
- Institute of Genomic Sciences, National Yang-Ming University; Institute of Molecular Biology, Academia Sinica;
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36
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Ghaemi R, Rezai P, Nejad FR, Selvaganapathy PR. Characterization of microfluidic clamps for immobilizing and imaging of Drosophila melanogaster larva's central nervous system. BIOMICROFLUIDICS 2017; 11:034113. [PMID: 28580046 PMCID: PMC5446281 DOI: 10.1063/1.4984767] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/18/2017] [Indexed: 05/16/2023]
Abstract
Drosophila melanogaster is a well-established model organism to understand biological processes and study human diseases at the molecular-genetic level. The central nervous system (CNS) of Drosophila larvae is widely used as a model to study neuron development and network formation. This has been achieved by using various genetic manipulation tools such as microinjection to knock down certain genes or over-express proteins for visualizing the cellular activities. However, visualization of an intact-live neuronal response in larva's Central Nervous System (CNS) is challenging due to robust digging/burrowing behaviour that impedes neuroimaging. To address this problem, dissection is used to isolate and immobilize the CNS from the rest of the body. In order to obtain a true physiological response from the Drosophila CNS, it is important to avoid dissection, while the larva should be kept immobilized. In this paper, a series of microfluidic clamps were investigated for intact immobilization of the larva. As a result, an optimized structure for rapid mechanical immobilization of Drosophila larvae for CNS imaging was determined. The clamping and immobilization processes were characterized by imaging and movement measurement of the CNS through the expression of genetically encoded Calcium sensor GCaMP5 in all sensory and cholinergic interneurons. The optimal structure that included two 3D constrictions inside a narrowed channel considerably reduced the internal CNS capsule movements. It restricts the CNS movement to 10% of the motion from a glued larva and allows motion of only 10 ± 30 μm over 350 s immobilization which was sufficient for CNS imaging. These larva-on-a-chip platforms can be useful for studying CNS responses to sensory cues such as sound, light, chemosensory, tactile, and electric/magnetic fields.
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Affiliation(s)
- Reza Ghaemi
- Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Pouya Rezai
- Department of Mechanical Engineering, York University, Toronto, Ontario M3J 1P3, Canada
| | - Fatemeh Rafiei Nejad
- Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4L8, Canada
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37
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Ardeshiri R, Rezai P. Lab-on-chips for manipulation of small-scale organisms to facilitate imaging of neurons and organs. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:5749-5752. [PMID: 28269560 DOI: 10.1109/embc.2016.7592033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Caenorhabditis elegans (C. elegans) and Drosophila melanogaster (D. melanogaster) are widely-used model organisms for neurological and cardiac studies due to their simple neuronal (302 neurons in C. elegans) and cardiac (simple tubular organ in D. melanogaster) systems. However, their small sizes and continuous mobility impede their precise and timely manipulation, hence, limiting the assays that can be done using conventional manual methods. This has resulted in a need for technologies that allow multidirectional manipulation of model organisms to enable studies on target neurons and organs throughout the body. By integration of rotatable glass capillaries with pneumatic suction into microfluidic devices, we propose novel Lab-on-Chips for multi-directional manipulation and imaging of small organisms. These hybrid Lab-on-Chips can facilitate the processes of animal handling and stimuli control, using modules for single-organism selection, orientation, imaging and chemical stimulation. We show the applications of these hybrid microdevices in manipulating C. elegans for neuronal imaging (neuron-level assay) or D. melanogaster for heart screening (organ level assay). These devices can enhance the throughput of biological assays on whole-organisms and find their applications in drug discovery and toxicology.
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38
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Regeneration of axotomized olfactory neurons in young and adult locusts quantified by fasciclin I immunofluorescence. Cell Tissue Res 2017; 368:1-12. [PMID: 28150067 DOI: 10.1007/s00441-016-2560-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/05/2016] [Indexed: 01/22/2023]
Abstract
The olfactory pathway of the locust Locusta migratoria is characterized by a multiglomerular innervation of the antennal lobe (AL) by olfactory receptor neurons (ORNs). After crushing the antenna and thereby severing ORN axons, changes in the AL were monitored. First, volume changes were measured at different times post-crush with scanning laser optical tomography in 5th instar nymphs. AL volume decreased significantly to a minimum volume at 4 days post-crush, followed by an increase. Second, anterograde labeling was used to visualize details in the AL and antennal nerve (AN) during de- and regeneration. Within 24 h post-crush (hpc) the ORN fragments distal to the lesion degenerated. After 48 hpc, regenerating fibers grew through the crush site. In the AL, labeled ORN projections disappeared completely and reappeared after a few days. A weak topographic match between ORN origin on the antenna and the position of innervated glomeruli that was present in untreated controls did not reappear after regeneration. Third, the cell surface marker fasciclin I that is expressed in ORNs was used for quantifying purposes. Immunofluorescence was measured in the AL during de- and regeneration in adults and 5th instar nymphs: after a rapid but transient, decrease, it reappeared. Both processes happen faster in 5th instar nymphs than in adults.
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39
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A microfluidics-based method for measuring neuronal activity in Drosophila chemosensory neurons. Nat Protoc 2016; 11:2389-2400. [PMID: 27809317 DOI: 10.1038/nprot.2016.144] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Monitoring neuronal responses to defined sensory stimuli is a powerful and widely used approach for understanding sensory coding in the nervous system. However, providing precise, stereotypic and reproducible cues while concomitantly recording neuronal activity remains technically challenging. Here we describe the fabrication and use of a microfluidics system that allows precise temporally restricted stimulation of Drosophila chemosensory neurons with an array of different chemical cues. The system can easily be combined with genetically encoded calcium sensors, and it can measure neuronal activity at single-cell resolution in larval sense organs and in the proboscis or leg of the adult fly. We describe the design of the master mold, the production of the microfluidic chip and live imaging using the calcium sensor GCaMP, expressed in distinct types of Drosophila chemosensory neurons. Fabrication of the master mold and microfluidic chips requires basic skills in photolithography and takes ∼2 weeks; the same devices can be used repeatedly over several months. Flies can be prepared for measurements in minutes and imaged for up to 1 h.
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40
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Wu Z, Fu Q, Yu S, Sheng L, Xu M, Yao C, Xiao W, Li X, Tang Y. Pt@AuNPs integrated quantitative capillary-based biosensors for point-of-care testing application. Biosens Bioelectron 2016; 85:657-663. [DOI: 10.1016/j.bios.2016.05.074] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 05/06/2016] [Accepted: 05/23/2016] [Indexed: 10/21/2022]
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41
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Long Term Ex Vivo Culture and Live Imaging of Drosophila Larval Imaginal Discs. PLoS One 2016; 11:e0163744. [PMID: 27685172 PMCID: PMC5042436 DOI: 10.1371/journal.pone.0163744] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/13/2016] [Indexed: 12/27/2022] Open
Abstract
Continuous imaging of live tissues provides clear temporal sequence of biological events. The Drosophila imaginal discs have been popular experimental subjects for the study of a wide variety of biological phenomena, but long term culture that allows normal development has not been satisfactory. Here we report a culture method that can sustain normal development for 18 hours and allows live imaging. The method is validated in multiple discs and for cell proliferation, differentiation and migration. However, it does not support disc growth and cannot support cell proliferation for more than 7 to 12 hr. We monitored the cellular behavior of retinal basal glia in the developing eye disc and found that distinct glia type has distinct properties of proliferation and migration. The live imaging provided direct proof that wrapping glia differentiated from existing glia after migrating to the anterior front, and unexpectedly found that they undergo endoreplication before wrapping axons, and their nuclei migrate up and down along the axons. UV-induced specific labeling of a single carpet glia also showed that the two carpet glia membrane do not overlap and suggests a tiling or repulsion mechanism between the two cells. These findings demonstrated the usefulness of an ex vivo culture method and live imaging.
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42
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Levario TJ, Lim B, Shvartsman SY, Lu H. Microfluidics for High-Throughput Quantitative Studies of Early Development. Annu Rev Biomed Eng 2016; 18:285-309. [PMID: 26928208 DOI: 10.1146/annurev-bioeng-100515-013926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Developmental biology has traditionally relied on qualitative analyses; recently, however, as in other fields of biology, researchers have become increasingly interested in acquiring quantitative knowledge about embryogenesis. Advances in fluorescence microscopy are enabling high-content imaging in live specimens. At the same time, microfluidics and automation technologies are increasing experimental throughput for studies of multicellular models of development. Furthermore, computer vision methods for processing and analyzing bioimage data are now leading the way toward quantitative biology. Here, we review advances in the areas of fluorescence microscopy, microfluidics, and data analysis that are instrumental to performing high-content, high-throughput studies in biology and specifically in development. We discuss a case study of how these techniques have allowed quantitative analysis and modeling of pattern formation in the Drosophila embryo.
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Affiliation(s)
- Thomas J Levario
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332;
| | - Bomyi Lim
- Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544;
| | - Stanislav Y Shvartsman
- Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544;
| | - Hang Lu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332;
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43
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Leung JCK, Hilliker AJ, Rezai P. An integrated hybrid microfluidic device for oviposition-based chemical screening of adult Drosophila melanogaster. LAB ON A CHIP 2016; 16:709-719. [PMID: 26768402 DOI: 10.1039/c5lc01517k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chemical screening using Drosophila melanogaster (the fruit fly) is vital in drug discovery, agricultural, and toxicological applications. Oviposition (egg laying) on chemically-doped agar plates is an important read-out metric used to quantitatively assess the biological fitness and behavioral responses of Drosophila. Current oviposition-based chemical screening studies are inaccurate, labor-intensive, time-consuming, and inflexible due to the manual chemical doping of agar. In this paper, we have developed a novel hybrid agar-polydimethylsiloxane (PDMS) microfluidic device for single- and multi-concentration chemical dosing and on-chip oviposition screening of free-flying adult stage Drosophila. To achieve this, we have devised a novel technique to integrate agar with PDMS channels using ice as a sacrificial layer. Subsequently, we have conducted single-chemical toxicity and multiple choice chemical preference assays on adult Drosophila melanogaster using zinc and acetic acid at various concentrations. Our device has enabled us to 1) demonstrate that Drosophila is capable of sensing the concentration of different chemicals on a PDMS-agar microfluidic device, which plays significant roles in determining oviposition site selection and 2) investigate whether oviposition preference differs between single- and multi-concentration chemical environments. This device may be used to study fundamental and applied biological questions in Drosophila and other egg laying insects. It can also be extended in design to develop sophisticated and dynamic chemical dosing and high-throughput screening platforms in the future that are not easily achievable with the existing oviposition screening techniques.
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Affiliation(s)
- Jacob C K Leung
- Department of Mechanical Engineering, York University, BCEE 433B, 4700 Keele St, Toronto, ON M3J 1P3, Canada.
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44
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Calcium Imaging of Neuronal Activity in Drosophila Can Identify Anticonvulsive Compounds. PLoS One 2016; 11:e0148461. [PMID: 26863447 PMCID: PMC4749298 DOI: 10.1371/journal.pone.0148461] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/18/2016] [Indexed: 12/17/2022] Open
Abstract
Although there are now a number of antiepileptic drugs (AEDs) available, approximately one-third of epilepsy patients respond poorly to drug intervention. The reasons for this are complex, but are probably reflective of the increasing number of identified mutations that predispose individuals to this disease. Thus, there is a clear requirement for the development of novel treatments to address this unmet clinical need. The existence of gene mutations that mimic a seizure-like behaviour in the fruit fly, Drosophila melanogaster, offers the possibility to exploit the powerful genetics of this insect to identify novel cellular targets to facilitate design of more effective AEDs. In this study we use neuronal expression of GCaMP, a potent calcium reporter, to image neuronal activity using a non-invasive and rapid method. Expression in motoneurons in the isolated CNS of third instar larvae shows waves of calcium-activity that pass between segments of the ventral nerve cord. Time between calcium peaks, in the same neurons, between adjacent segments usually show a temporal separation of greater than 200 ms. Exposure to proconvulsants (picrotoxin or 4-aminopyridine) reduces separation to below 200 ms showing increased synchrony of activity across adjacent segments. Increased synchrony, characteristic of epilepsy, is similarly observed in genetic seizure mutants: bangsenseless1 (bss1) and paralyticK1270T (paraK1270T). Exposure of bss1 to clinically-used antiepileptic drugs (phenytoin or gabapentin) significantly reduces synchrony. In this study we use the measure of synchronicity to evaluate the effectiveness of known and novel anticonvulsive compounds (antipain, isethionate, etopiside rapamycin and dipyramidole) to reduce seizure-like CNS activity. We further show that such compounds also reduce the Drosophila voltage-gated persistent Na+ current (INaP) in an identified motoneuron (aCC). Our combined assays provide a rapid and reliable method to screen unknown compounds for potential to function as anticonvulsants.
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45
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Ardeshiri R, Hosseini L, Amini N, Rezai P. Cardiac screening of intact Drosophila melanogaster larvae under exposure to aqueous and gaseous toxins in a microfluidic device. RSC Adv 2016. [DOI: 10.1039/c6ra14159e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We present a semi-automated microfluidic chip for orientation, immobilization, chemical exposure, and cardiac screening of 3rd instar Drosophila melanogaster larvae.
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Affiliation(s)
- R. Ardeshiri
- Department of Mechanical Engineering
- York University
- Toronto
- Canada
| | - L. Hosseini
- Department of Mechanical Engineering
- York University
- Toronto
- Canada
| | - N. Amini
- Department of Mechanical Engineering
- York University
- Toronto
- Canada
| | - P. Rezai
- Department of Mechanical Engineering
- York University
- Toronto
- Canada
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46
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Leung JCK, Taylor-Kamall RW, Hilliker AJ, Rezai P. Agar-polydimethylsiloxane devices for quantitative investigation of oviposition behaviour of adult Drosophila melanogaster. BIOMICROFLUIDICS 2015; 9:034112. [PMID: 26180569 PMCID: PMC4482806 DOI: 10.1063/1.4922737] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 06/08/2015] [Indexed: 06/04/2023]
Abstract
Drosophila melanogaster (fruit fly) is a model organism and its behaviours including oviposition (egg-laying) on agar substrates have been widely used for assessment of a variety of biological processes in flies. Physical and chemical properties of the substrate are the dominant factors affecting Drosophila's oviposition, but they have not been investigated precisely and parametrically with the existing manual approaches. As a result, many behavioral questions about Drosophila oviposition, such as the combined effects of the aforementioned substrate properties (e.g., exposure area, sugar content, and stiffness) on oviposition and viability, and their threshold values, are yet to be answered. In this paper, we have devised a simple, easily implementable, and novel methodology that allows for modification of physical and chemical composition of agar substrates in order to quantitatively study survival and oviposition of adult fruit flies in an accurate and repeatable manner. Agar substrates have been modified by surface patterning using single and hexagonally arrayed through-hole polydimethylsiloxane (PDMS) membranes with various diameters and interspacing, as well as by substrate stiffness and sugar content modification via alteration of chemical components. While pure PDMS substrates showed a significant lethal effect on flies, a 0.5 mm diameter through-hole access to agar was found to abruptly increase the survival of adult flies to more than 93%. Flies avoided ovipositing on pure PDMS and on top of substrates with 0.5 mm diameter agar exposure areas. At a hole diameter of 2 mm (i.e., 0.25% exposure area) or larger, eggs were observed to be laid predominately inside the through-holes and along the edges of the PDMS-agar interface, showing a trending increase in site selection with 4 mm (i.e., 1% exposure area threshold) demonstrating natural oviposition rates similar to pure agar. The surface-modified agar-PDMS hybrid devices and the threshold values reported for the substrate physical and chemical conditions affecting oviposition are novel; therefore, we advocate their use for future in-depth studies of oviposition behaviour in Drosophila melanogaster with accuracy and repeatability. The technique is also useful for development of novel assays for learning and decision-making studies as well as miniaturized devices for self-assembly of eggs and embryonic developmental investigations.
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Affiliation(s)
- Jacob C K Leung
- Department of Mechanical Engineering, Lassonde School of Engineering, York University , Toronto, Ontario M3J 1P3, Canada
| | | | - Arthur J Hilliker
- Department of Biology, York University , Toronto, Ontario M3J 1P3, Canada
| | - Pouya Rezai
- Department of Mechanical Engineering, Lassonde School of Engineering, York University , Toronto, Ontario M3J 1P3, Canada
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47
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Medioni C, Ephrussi A, Besse F. Live imaging of axonal transport in Drosophila pupal brain explants. Nat Protoc 2015; 10:574-84. [PMID: 25763834 DOI: 10.1038/nprot.2015.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Axonal transport is essential for the initial growth, maintenance and synaptic plasticity of axons, and altered axonal transport has been observed in different models of neurodegenerative pathologies. Dissecting the mechanisms underlying axonal transport in developing or degenerating brains requires dynamic imaging of axonal cargo movement in living samples. Whereas methods exist to image axonal transport in Drosophila larval neurons, they are not suitable to follow this process during metamorphosis, when brains undergo extensive remodeling. Here we present a simple method that enables confocal imaging of both fast and slow axonal transport in Drosophila pupal brain explants. We describe how to prepare chambers adapted for live imaging, how to maintain brain explants under physiological conditions and how to monitor and quantitatively analyze the movement of fluorescently labeled cargoes. This protocol requires minimal equipment and is ideally suited for experiments that combine genetics, optogenetics and pharmacological approaches. The brains can be prepared for image acquisition in 1.5 h, and the protocol can be performed easily in any fly laboratory.
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Affiliation(s)
- Caroline Medioni
- Institute of Biology Valrose, Centre National de la Recherche Scientifique (CNRS)-Unité Mixte de Recherche (UMR) 7277, Institut National de la Santé et de la Recherche Médicale (INSERM)-UMR1091, University of Nice-Sophia Antipolis, Nice, France
| | | | - Florence Besse
- Institute of Biology Valrose, Centre National de la Recherche Scientifique (CNRS)-Unité Mixte de Recherche (UMR) 7277, Institut National de la Santé et de la Recherche Médicale (INSERM)-UMR1091, University of Nice-Sophia Antipolis, Nice, France
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48
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Ghaemi R, Rezai P, Iyengar BG, Selvaganapathy PR. Microfluidic devices for imaging neurological response of Drosophila melanogaster larva to auditory stimulus. LAB ON A CHIP 2015; 15:1116-22. [PMID: 25536889 DOI: 10.1039/c4lc01245c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Two microfluidic devices (pneumatic chip and FlexiChip) have been developed for immobilization and live-intact fluorescence functional imaging of Drosophila larva's Central Nervous System (CNS) in response to controlled acoustic stimulation. The pneumatic chip is suited for automated loading/unloading and potentially allows high throughput operation for studies with a large number of larvae while the FlexiChip provides a simple and quick manual option for animal loading and is suited for smaller studies. Both chips were capable of significantly reducing the endogenous CNS movement while still allowing the study of sound-stimulated CNS activities of Drosophila 3rd instar larvae using genetically encoded calcium indicator GCaMP5. Temporal effects of sound frequency (50-5000 Hz) and intensity (95-115 dB) on CNS activities were investigated and a peak neuronal response of 200 Hz was identified. Our lab-on-chip devices can not only aid further studies of Drosophila larva's auditory responses but can be also adopted for functional imaging of CNS activities in response to other sensory cues. Auditory stimuli and the corresponding response of the CNS can potentially be used as a tool to study the effect of chemicals on the neurophysiology of this model organism.
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Affiliation(s)
- Reza Ghaemi
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada.
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Lu W, Lakonishok M, Gelfand VI. Kinesin-1-powered microtubule sliding initiates axonal regeneration in Drosophila cultured neurons. Mol Biol Cell 2015; 26:1296-307. [PMID: 25657321 PMCID: PMC4454177 DOI: 10.1091/mbc.e14-10-1423] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Microtubule sliding drives initial axon regeneration in Drosophila neurons. Axotomy leads to fast calcium influx and subsequent microtubule reorganization. Kinesin-1 heavy chain drives the sliding of antiparallel microtubules to power axonal regrowth, and the JNK pathway promotes axonal regeneration by enhancing microtubule sliding. Understanding the mechanism underlying axon regeneration is of great practical importance for developing therapeutic treatment for traumatic brain and spinal cord injuries. Dramatic cytoskeleton reorganization occurs at the injury site, and microtubules have been implicated in the regeneration process. Previously we demonstrated that microtubule sliding by conventional kinesin (kinesin-1) is required for initiation of neurite outgrowth in Drosophila embryonic neurons and that sliding is developmentally down-regulated when neurite outgrowth is completed. Here we report that mechanical axotomy of Drosophila neurons in culture triggers axonal regeneration and regrowth. Regenerating neurons contain actively sliding microtubules; this sliding, like sliding during initial neurite outgrowth, is driven by kinesin-1 and is required for axonal regeneration. The injury induces a fast spike of calcium, depolymerization of microtubules near the injury site, and subsequent formation of local new microtubule arrays with mixed polarity. These events are required for reactivation of microtubule sliding at the initial stages of regeneration. Furthermore, the c-Jun N-terminal kinase pathway promotes regeneration by enhancing microtubule sliding in injured mature neurons.
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Affiliation(s)
- Wen Lu
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Margot Lakonishok
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
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50
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On-chip immobilization of planarians for in vivo imaging. Sci Rep 2014; 4:6388. [PMID: 25227263 PMCID: PMC4165980 DOI: 10.1038/srep06388] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 08/14/2014] [Indexed: 11/08/2022] Open
Abstract
Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra.
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