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Fryer E, Guha S, Rogel-Hernandez LE, Logan-Garbisch T, Farah H, Rezaei E, Mollhoff IN, Nekimken AL, Xu A, Selin Seyahi L, Fechner S, Druckmann S, Clandinin TR, Rhee SY, Goodman MB. An efficient behavioral screening platform classifies natural products and other chemical cues according to their chemosensory valence in C. elegans. bioRxiv 2024:2023.06.02.542933. [PMID: 37333363 PMCID: PMC10274637 DOI: 10.1101/2023.06.02.542933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Throughout history, humans have relied on plants as a source of medication, flavoring, and food. Plants synthesize large chemical libraries and release many of these compounds into the rhizosphere and atmosphere where they affect animal and microbe behavior. To survive, nematodes must have evolved the sensory capacity to distinguish plant-made small molecules (SMs) that are harmful and must be avoided from those that are beneficial and should be sought. This ability to classify chemical cues as a function of their value is fundamental to olfaction, and represents a capacity shared by many animals, including humans. Here, we present an efficient platform based on multi-well plates, liquid handling instrumentation, inexpensive optical scanners, and bespoke software that can efficiently determine the valence (attraction or repulsion) of single SMs in the model nematode, Caenorhabditis elegans. Using this integrated hardware-wetware-software platform, we screened 90 plant SMs and identified 37 that attracted or repelled wild-type animals, but had no effect on mutants defective in chemosensory transduction. Genetic dissection indicates that for at least 10 of these SMs, response valence emerges from the integration of opposing signals, arguing that olfactory valence is often determined by integrating chemosensory signals over multiple lines of information. This study establishes that C. elegans is an effective discovery engine for determining chemotaxis valence and for identifying natural products detected by the chemosensory nervous system.
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Affiliation(s)
- Emily Fryer
- Department of Plant Biology, Carnegie Institution for Science
- Department of Molecular and Cellular Physiology, Stanford University
| | - Sujay Guha
- Department of Molecular and Cellular Physiology, Stanford University
| | | | - Theresa Logan-Garbisch
- Department of Molecular and Cellular Physiology, Stanford University
- Neurosciences Graduate Program, Stanford University
| | - Hodan Farah
- Department of Plant Biology, Carnegie Institution for Science
- Department of Molecular and Cellular Physiology, Stanford University
| | - Ehsan Rezaei
- Department of Molecular and Cellular Physiology, Stanford University
| | - Iris N. Mollhoff
- Department of Plant Biology, Carnegie Institution for Science
- Department of Molecular and Cellular Physiology, Stanford University
- Department of Biology, Stanford University
| | - Adam L. Nekimken
- Department of Molecular and Cellular Physiology, Stanford University
- Department of Mechanical Engineering, Stanford University
| | - Angela Xu
- Department of Plant Biology, Carnegie Institution for Science
| | - Lara Selin Seyahi
- Department of Plant Biology, Carnegie Institution for Science
- Department of Molecular and Cellular Physiology, Stanford University
| | - Sylvia Fechner
- Department of Molecular and Cellular Physiology, Stanford University
| | | | | | - Seung Y. Rhee
- Department of Plant Biology, Carnegie Institution for Science
| | - Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University
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2
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Abstract
This Viewpoint, which accompanies a Special Issue focusing on membrane mechanosensors, discusses unifying and unique features of both established and emerging mechanosensitive (MS) membrane proteins, their distribution across protein families and phyla, and current and future challenges in the study of these important proteins and their partners. MS membrane proteins are essential for tissue development, cellular motion, osmotic homeostasis, and sensing external and self-generated mechanical cues like those responsible for touch and proprioception. Though researchers' attention and this Viewpoint focus on a few famous ion channels that are considered the usual suspects as MS mechanosensors, we also discuss some of the more unusual suspects, such as G-protein coupled receptors. As the field continues to grow, so too will the list of proteins suspected to function as mechanosensors and the diversity of known MS membrane proteins.
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Affiliation(s)
- Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Elizabeth S. Haswell
- Department of Biology, Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
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3
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Abstract
The visualization of mechanical stress distribution in specific molecular networks within a living and physiologically active cell or animal remains a formidable challenge in mechanobiology. The advent of fluorescence-resonance energy transfer (FRET)-based molecular tension sensors overcame a significant hurdle that now enables us to address previously technically limited questions. Here, we describe a method that uses genetically encoded FRET tension sensors to visualize the mechanics of cytoskeletal networks in neurons of living animals with sensitized emission FRET and confocal scanning light microscopy. This method uses noninvasive immobilization of living animals to image neuronal β-spectrin cytoskeleton at the diffraction limit, and leverages multiple imaging controls to verify and underline the quality of the measurements. In combination with a semiautomated machine-vision algorithm to identify and trace individual neurites, our analysis performs simultaneous calculation of FRET efficiencies and visualizes statistical uncertainty on a pixel by pixel basis. Our approach is not limited to genetically encoded spectrin tension sensors, but can also be used for any kind of ratiometric imaging in neuronal cells both in vivo and in vitro.
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Affiliation(s)
- Neus Sanfeliu-Cerdán
- Neurophotonics and Mechanical Systems Biology, ICFO, Institut de Ciències Fotòniques, ICFO, Castelldefels, Spain
| | - Li-Chun Lin
- Neurophotonics and Mechanical Systems Biology, ICFO, Institut de Ciències Fotòniques, ICFO, Castelldefels, Spain
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Miriam B Goodman
- Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Michael Krieg
- Neurophotonics and Mechanical Systems Biology, ICFO, Institut de Ciències Fotòniques, ICFO, Castelldefels, Spain.
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4
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Wang LM, Goodman MB, Kuhl E. Image-based axon model highlights heterogeneity in initiation of damage. Biophys J 2023; 122:9-19. [PMID: 36461640 PMCID: PMC9822833 DOI: 10.1016/j.bpj.2022.11.2946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/29/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
Head injury simulations predict the occurrence of traumatic brain injury by placing a threshold on the calculated strains for axon tracts within the brain. However, a current roadblock to accurate injury prediction is the selection of an appropriate axon damage threshold. While several computational studies have used models of the axon cytoskeleton to investigate damage initiation, these models all employ an idealized, homogeneous axonal geometry. This homogeneous geometry with regularly spaced microtubules, evenly distributed throughout the model, overestimates axon strength because, in reality, the axon cytoskeleton is heterogeneous. In the heterogeneous cytoskeleton, the weakest cross section determines the initiation of failure, but these weak spots are not present in a homogeneous model. Addressing one source of heterogeneity in the axon cytoskeleton, we present a new semiautomated image analysis pipeline for using serial-section transmission electron micrographs to reconstruct the microtubule geometry of an axon. The image analysis procedure locates microtubules within the images, traces them throughout the image stack, and reconstructs the microtubule structure as a finite element mesh. We demonstrate the image analysis approach using a C. elegans touch receptor neuron due to the availability of high-quality serial-section transmission electron micrograph data sets. The results of the analysis highlight the heterogeneity of the microtubule structure in the spatial variation of both microtubule number and length. Simulations comparing this image-based geometry with homogeneous geometries show that structural heterogeneity in the image-based model creates significant spatial variation in deformation. The homogeneous geometries, on the other hand, deform more uniformly. Since no single homogeneous model can replicate the mechanical behavior of the image-based model, our results argue that heterogeneity in axon microtubule geometry should be considered in determining accurate axon failure thresholds.
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Affiliation(s)
- Lucy M Wang
- Department of Mechanical Engineering, Stanford University, Stanford, California.
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California
| | - Ellen Kuhl
- Department of Mechanical Engineering, Stanford University, Stanford, California
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5
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McLellan CA, Siefe C, Casar JR, Peng CS, Fischer S, Lay A, Parakh A, Ke F, Gu XW, Mao W, Chu S, Goodman MB, Dionne JA. Engineering Bright and Mechanosensitive Alkaline-Earth Rare-Earth Upconverting Nanoparticles. J Phys Chem Lett 2022; 13:1547-1553. [PMID: 35133831 PMCID: PMC9587901 DOI: 10.1021/acs.jpclett.1c03841] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Upconverting nanoparticles (UCNPs) are an emerging platform for mechanical force sensing at the nanometer scale. An outstanding challenge in realizing nanometer-scale mechano-sensitive UCNPs is maintaining a high mechanical force responsivity in conjunction with bright optical emission. This Letter reports mechano-sensing UCNPs based on the lanthanide dopants Yb3+ and Er3+, which exhibit a strong ratiometric change in emission spectra and bright emission under applied pressure. We synthesize and analyze the pressure response of five different types of nanoparticles, including cubic NaYF4 host nanoparticles and alkaline-earth host materials CaLuF, SrLuF, SrYbF, and BaLuF, all with lengths of 15 nm or less. By combining optical spectroscopy in a diamond anvil cell with single-particle brightness, we determine the noise equivalent sensitivity (GPa/√Hz) of these particles. The SrYb0.72Er0.28F@SrLuF particles exhibit an optimum noise equivalent sensitivity of 0.26 ± 0.04 GPa/√Hz. These particles present the possibility of robust nanometer-scale mechano-sensing.
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Affiliation(s)
- Claire A McLellan
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Chris Siefe
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Jason R Casar
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Chunte Sam Peng
- Department of Physics, Stanford University, Stanford, California 94305, United States
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Stefan Fischer
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Alice Lay
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Abhinav Parakh
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Feng Ke
- Department of Geological Sciences, Stanford University, Stanford, California 94305, United States
| | - X Wendy Gu
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Wendy Mao
- Department of Geological Sciences, Stanford University, Stanford, California 94305, United States
| | - Steven Chu
- Department of Physics, Stanford University, Stanford, California 94305, United States
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Jennifer A Dionne
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Radiology, Stanford University, Stanford, California 94305, United States
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6
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Goodman MB, Savage-Dunn C. Reciprocal interactions between transforming growth factor beta signaling and collagens: Insights from Caenorhabditis elegans. Dev Dyn 2022; 251:47-60. [PMID: 34537996 PMCID: PMC8982858 DOI: 10.1002/dvdy.423] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/13/2021] [Accepted: 09/13/2021] [Indexed: 01/03/2023] Open
Abstract
Studies in genetically tractable organisms such as the nematode Caenorhabditis elegans have led to pioneering insights into conserved developmental regulatory mechanisms. For example, Smad signal transducers for the transforming growth factor beta (TGF-β) superfamily were first identified in C. elegans and in the fruit fly Drosophila. Recent studies of TGF-β signaling and the extracellular matrix (ECM) in C. elegans have forged unexpected links between signaling and the ECM, yielding novel insights into the reciprocal interactions that occur across tissues and spatial scales, and potentially providing new opportunities for the study of biomechanical regulation of gene expression.
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Affiliation(s)
- Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, CA 94304
| | - Cathy Savage-Dunn
- Department of Biology, Queens College at the City University of New York, 11367,Correspondence to: >
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7
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Fechner S, D'Alessandro I, Wang L, Tower C, Tao L, Goodman MB. DEG/ENaC/ASIC channels vary in their sensitivity to anti-hypertensive and non-steroidal anti-inflammatory drugs. J Gen Physiol 2021; 153:211847. [PMID: 33656557 PMCID: PMC7933985 DOI: 10.1085/jgp.202012655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 01/12/2021] [Indexed: 12/19/2022] Open
Abstract
The degenerin channels, epithelial sodium channels, and acid-sensing ion channels (DEG/ENaC/ASICs) play important roles in sensing mechanical stimuli, regulating salt homeostasis, and responding to acidification in the nervous system. They have two transmembrane domains separated by a large extracellular domain and are believed to assemble as homomeric or heteromeric trimers. Based on studies of selected family members, these channels are assumed to form nonvoltage-gated and sodium-selective channels sensitive to the anti-hypertensive drug amiloride. They are also emerging as a target of nonsteroidal anti-inflammatory drugs (NSAIDs). Caenorhabditis elegans has more than two dozen genes encoding DEG/ENaC/ASIC subunits, providing an excellent opportunity to examine variations in drug sensitivity. Here, we analyze a subset of the C. elegans DEG/ENaC/ASIC proteins to test the hypothesis that individual family members vary not only in their ability to form homomeric channels but also in their drug sensitivity. We selected a panel of C. elegans DEG/ENaC/ASICs that are coexpressed in mechanosensory neurons and expressed gain-of-function or d mutants in Xenopus laevis oocytes. We found that only DEGT‑1d, UNC‑8d, and MEC‑4d formed homomeric channels and that, unlike MEC‑4d and UNC‑8d, DEGT‑1d channels were insensitive to amiloride and its analogues. As reported for rat ASIC1a, NSAIDs inhibit DEGT‑1d and UNC‑8d channels. Unexpectedly, MEC‑4d was strongly potentiated by NSAIDs, an effect that was decreased by mutations in the putative NSAID-binding site in the extracellular domain. Collectively, these findings reveal that not all DEG/ENaC/ASIC channels are amiloride-sensitive and that NSAIDs can both inhibit and potentiate these channels.
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Affiliation(s)
- Sylvia Fechner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Isabel D'Alessandro
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Lingxin Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Calvin Tower
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Li Tao
- Department of Biology, Stanford University, Stanford, CA
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
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8
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Rezaei E, Savage-Dunn C, Goodman MB. Nanoscale Structure and Mechanics of Skin in a C. elegans Model of Touch Sensation. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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9
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Nekimken AL, Pruitt BL, Goodman MB. Touch-induced mechanical strain in somatosensory neurons is independent of extracellular matrix mutations in Caenorhabditis elegans. Mol Biol Cell 2020; 31:1735-1743. [PMID: 32579427 PMCID: PMC7521855 DOI: 10.1091/mbc.e20-01-0049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cutaneous mechanosensory neurons are activated by mechanical loads applied to the skin, and these stimuli are proposed to generate mechanical strain within sensory neurons. Using a microfluidic device to deliver controlled stimuli to intact animals and large, immobile, and fluorescent protein-tagged mitochondria as fiducial markers in the touch receptor neurons (TRNs), we visualized and measured touch-induced mechanical strain in Caenorhabditis elegans worms. At steady state, touch stimuli sufficient to activate TRNs induce an average strain of 3.1% at the center of the actuator and this strain decays to near zero at the edges of the actuator. We also measured strain in animals carrying mutations affecting links between the extracellular matrix (ECM) and the TRNs but could not detect any differences in touch-induced mechanical strain between wild-type and mutant animals. Collectively, these results demonstrate that touching the skin induces local mechanical strain in intact animals and suggest that a fully intact ECM is not essential for transmitting mechanical strain from the skin to cutaneous mechanosensory neurons.
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Affiliation(s)
- Adam L Nekimken
- Departments of Mechanical Engineering, Stanford University, Stanford, CA 94305.,Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Beth L Pruitt
- Departments of Mechanical Engineering, Stanford University, Stanford, CA 94305.,Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305.,Mechanical Engineering and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - Miriam B Goodman
- Departments of Mechanical Engineering, Stanford University, Stanford, CA 94305.,Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
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10
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Yu CC(J, Barry NC, Wassie AT, Sinha A, Bhattacharya A, Asano S, Zhang C, Chen F, Hobert O, Goodman MB, Haspel G, Boyden ES. Expansion microscopy of C. elegans. eLife 2020; 9:e46249. [PMID: 32356725 PMCID: PMC7195193 DOI: 10.7554/elife.46249] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 03/30/2020] [Indexed: 12/20/2022] Open
Abstract
We recently developed expansion microscopy (ExM), which achieves nanoscale-precise imaging of specimens at ~70 nm resolution (with ~4.5x linear expansion) by isotropic swelling of chemically processed, hydrogel-embedded tissue. ExM of C. elegans is challenged by its cuticle, which is stiff and impermeable to antibodies. Here we present a strategy, expansion of C. elegans (ExCel), to expand fixed, intact C. elegans. ExCel enables simultaneous readout of fluorescent proteins, RNA, DNA location, and anatomical structures at resolutions of ~65-75 nm (3.3-3.8x linear expansion). We also developed epitope-preserving ExCel, which enables imaging of endogenous proteins stained by antibodies, and iterative ExCel, which enables imaging of fluorescent proteins after 20x linear expansion. We demonstrate the utility of the ExCel toolbox for mapping synaptic proteins, for identifying previously unreported proteins at cell junctions, and for gene expression analysis in multiple individual neurons of the same animal.
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Affiliation(s)
- Chih-Chieh (Jay) Yu
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridgeUnited States
- Media Lab, Massachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Nicholas C Barry
- Media Lab, Massachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Asmamaw T Wassie
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Anubhav Sinha
- Media Lab, Massachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute, Massachusetts Institute of TechnologyCambridgeUnited States
- Division of Health Sciences and Technology, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Abhishek Bhattacharya
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Shoh Asano
- Media Lab, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Chi Zhang
- Media Lab, Massachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Fei Chen
- Broad Institute of MIT and HarvardCambridgeUnited States
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Gal Haspel
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University-NewarkNewarkUnited States
- The Brain Research Institute, New Jersey Institute of TechnologyNewarkUnited States
| | - Edward S Boyden
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridgeUnited States
- Media Lab, Massachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute, Massachusetts Institute of TechnologyCambridgeUnited States
- Koch Institute, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
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11
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Ellington CT, Hayden AJ, LaGrange ZB, Luccioni MD, Osman MA, Ramlan LI, Vogt MA, Guha S, Goodman MB, O'Connell LA. The plant terpenoid carvone is a chemotaxis repellent for C. elegans. MicroPubl Biol 2020; 2020:10.17912/micropub.biology.000231. [PMID: 32550506 PMCID: PMC7252383 DOI: 10.17912/micropub.biology.000231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Andrew J. Hayden
- Organismal Biology Lab BIO161, Stanford University, Stanford, CA 94305
| | - Zack B. LaGrange
- Organismal Biology Lab BIO161, Stanford University, Stanford, CA 94305
| | | | | | | | - Miranda A. Vogt
- Organismal Biology Lab BIO161, Stanford University, Stanford, CA 94305
| | - Sujay Guha
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305,
Correspondence to: Sujay Guha (); Miriam B. Goodman (); Lauren A. O'Connell ()
| | - Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305,
Correspondence to: Sujay Guha (); Miriam B. Goodman (); Lauren A. O'Connell ()
| | - Lauren A. O'Connell
- Department of Biology, Stanford University, Stanford, CA 94305,
Correspondence to: Sujay Guha (); Miriam B. Goodman (); Lauren A. O'Connell ()
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12
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Tao L, Porto D, Li Z, Fechner S, Lee SA, Goodman MB, Xu XZS, Lu H, Shen K. Parallel Processing of Two Mechanosensory Modalities by a Single Neuron in C. elegans. Dev Cell 2019; 51:617-631.e3. [PMID: 31735664 DOI: 10.1016/j.devcel.2019.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 05/24/2019] [Accepted: 10/14/2019] [Indexed: 10/25/2022]
Abstract
Neurons convert synaptic or sensory inputs into cellular outputs. It is not well understood how a single neuron senses, processes multiple stimuli, and generates distinct neuronal outcomes. Here, we describe the mechanism by which the C. elegans PVD neurons sense two mechanical stimuli: external touch and proprioceptive body movement. These two stimuli are detected by distinct mechanosensitive DEG/ENaC/ASIC channels, which trigger distinct cellular outputs linked to mechanonociception and proprioception. Mechanonociception depends on DEGT-1 and activates PVD's downstream command interneurons through its axon, while proprioception depends on DEL-1, UNC-8, and MEC-10 to induce local dendritic Ca2+ increase and dendritic release of a neuropeptide NLP-12. NLP-12 directly modulates neuromuscular junction activity through the cholecystokinin receptor homolog on motor axons, setting muscle tone and movement vigor. Thus, the same neuron simultaneously uses both its axon and dendrites as output apparatus to drive distinct sensorimotor outcomes.
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Affiliation(s)
- Li Tao
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA, USA
| | - Daniel Porto
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Zhaoyu Li
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sylvia Fechner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Sol Ah Lee
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - X Z Shawn Xu
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hang Lu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kang Shen
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA, USA.
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13
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Katta S, Sanzeni A, Das A, Vergassola M, Goodman MB. Progressive recruitment of distal MEC-4 channels determines touch response strength in C. elegans. J Gen Physiol 2019; 151:1213-1230. [PMID: 31533952 PMCID: PMC6785734 DOI: 10.1085/jgp.201912374] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 08/23/2019] [Indexed: 12/14/2022] Open
Abstract
Touch deforms, or strains, the skin beyond the immediate point of contact. The spatiotemporal nature of the touch-induced strain fields depend on the mechanical properties of the skin and the tissues below. Somatosensory neurons that sense touch branch out within the skin and rely on a set of mechano-electrical transduction channels distributed within their dendrites to detect mechanical stimuli. Here, we sought to understand how tissue mechanics shape touch-induced mechanical strain across the skin over time and how individual channels located in different regions of the strain field contribute to the overall touch response. We leveraged Caenorhabditis elegans' touch receptor neurons as a simple model amenable to in vivo whole-cell patch-clamp recording and an integrated experimental-computational approach to dissect the mechanisms underlying the spatial and temporal dynamics we observed. Consistent with the idea that strain is produced at a distance, we show that delivering strong stimuli outside the anatomical extent of the neuron is sufficient to evoke MRCs. The amplitude and kinetics of the MRCs depended on both stimulus displacement and speed. Finally, we found that the main factor responsible for touch sensitivity is the recruitment of progressively more distant channels by stronger stimuli, rather than modulation of channel open probability. This principle may generalize to somatosensory neurons with more complex morphologies.
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Affiliation(s)
- Samata Katta
- Neuroscience Program, Stanford University, Stanford, CA
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Alessandro Sanzeni
- National Institute of Mental Health Intramural Program, National Institutes of Health, Bethesda, MD
| | - Alakananda Das
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Massimo Vergassola
- Department of Physics, University of California, San Diego, La Jolla, CA
| | - Miriam B Goodman
- Neuroscience Program, Stanford University, Stanford, CA
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
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14
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Sanzeni A, Katta S, Petzold B, Pruitt BL, Goodman MB, Vergassola M. Somatosensory neurons integrate the geometry of skin deformation and mechanotransduction channels to shape touch sensing. eLife 2019; 8:43226. [PMID: 31407662 PMCID: PMC6692131 DOI: 10.7554/elife.43226] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 07/17/2019] [Indexed: 01/08/2023] Open
Abstract
Touch sensation hinges on force transfer across the skin and activation of mechanosensitive ion channels along the somatosensory neurons that invade the skin. This skin-nerve sensory system demands a quantitative model that spans the application of mechanical loads to channel activation. Unlike prior models of the dynamic responses of touch receptor neurons in Caenorhabditis elegans (Eastwood et al., 2015), which substituted a single effective channel for the ensemble along the TRNs, this study integrates body mechanics and the spatial recruitment of the various channels. We demonstrate that this model captures mechanical properties of the worm’s body and accurately reproduces neural responses to simple stimuli. It also captures responses to complex stimuli featuring non-trivial spatial patterns, like extended or multiple contacts that could not be addressed otherwise. We illustrate the importance of these effects with new experiments revealing that skin-neuron composites respond to pre-indentation with increased currents rather than adapting to persistent stimulation.
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Affiliation(s)
- Alessandro Sanzeni
- Department of Physics, University of California, San Diego, La Jolla, United States.,National Institute of Mental Health Intramural Program, National Institutes of Health, Bethesda, United States
| | - Samata Katta
- Neuroscience Program, Stanford University School of Medicine, Stanford, United States
| | - Bryan Petzold
- Department of Mechanical Engineering, Stanford University, Stanford, United States
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, United States.,Department of Bioengineering, Stanford University, Stanford, United States
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Massimo Vergassola
- Department of Physics, University of California, San Diego, La Jolla, United States
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15
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Abstract
Gentle touch sensation in mammals depends on synaptic transmission from primary sensory cells (Merkel cells) to secondary sensory neurons. Hoffman et al. (2018) identify norepinephrine and β2-adrendergic receptors as the neurotransmitter-receptor pair responsible for sustained touch responses. The findings may deepen understanding of how drugs affect touch and pain sensation.
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Affiliation(s)
- Sylvia Fechner
- Department of Molecular and Cellular Physiology, Stanford, CA 94305, USA
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford, CA 94305, USA.
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16
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Lay A, Sheppard OH, Siefe C, McLellan CA, Mehlenbacher RD, Fischer S, Goodman MB, Dionne JA. Optically Robust and Biocompatible Mechanosensitive Upconverting Nanoparticles. ACS Cent Sci 2019; 5:1211-1222. [PMID: 31403071 PMCID: PMC6661856 DOI: 10.1021/acscentsci.9b00300] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Indexed: 05/05/2023]
Abstract
Upconverting nanoparticles (UCNPs) are promising tools for background-free imaging and sensing. However, their usefulness for in vivo applications depends on their biocompatibility, which we define by their optical performance in biological environments and their toxicity in living organisms. For UCNPs with a ratiometric color response to mechanical stress, consistent emission intensity and color are desired for the particles under nonmechanical stimuli. Here, we test the biocompatibility and mechanosensitivity of α-NaYF4:Yb,Er@NaLuF4 nanoparticles. First, we ligand-strip these particles to render them dispersible in aqueous media. Then, we characterize their mechanosensitivity (∼30% in the red-to-green spectral ratio per GPa), which is nearly 3-fold greater than those coated in oleic acid. We next design a suite of ex vivo and in vivo tests to investigate their structural and optical properties under several biorelevant conditions: over time in various buffers types, as a function of pH, and in vivo along the digestive tract of Caenorhabditis elegans worms. Finally, to ensure that the particles do not perturb biological function in C. elegans, we assess the chronic toxicity of nanoparticle ingestion using a reproductive brood assay. In these ways, we determine that mechanosensitive UCNPs are biocompatible, i.e., optically robust and nontoxic, for use as in vivo sensors to study animal digestion.
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Affiliation(s)
- Alice Lay
- Department
of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Olivia H. Sheppard
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Chris Siefe
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Claire A. McLellan
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Randy D. Mehlenbacher
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Stefan Fischer
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Miriam B. Goodman
- Department
of Molecular and Cellular Physiology, Stanford
University, Stanford, California 94305, United States
| | - Jennifer A. Dionne
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
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17
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Affiliation(s)
- Jennifer L Raymond
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA.
| | - Miriam B Goodman
- Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
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18
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Fechner S, Loizeau F, Nekimken AL, Pruitt BL, Goodman MB. The bodies of dpy-10(e128) are twice as stiff as wild type. MicroPubl Biol 2018; 2018. [PMID: 32550396 PMCID: PMC7282522 DOI: 10.17912/ecsm-mp67] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sylvia Fechner
- Molecular and Cellular Physiology, Stanford School of Medicine, Stanford
| | - Frédéric Loizeau
- Departments of Bioengineering and Mechanical Engineering, Stanford
| | - Adam L Nekimken
- Molecular and Cellular Physiology, Stanford School of Medicine, Stanford.,Departments of Bioengineering and Mechanical Engineering, Stanford
| | - Beth L Pruitt
- Departments of Bioengineering and Mechanical Engineering, Stanford.,Departments of Mechanical Engineering and Biomolecular Science and Engineering, University of California, Santa Barbara
| | - Miriam B Goodman
- Molecular and Cellular Physiology, Stanford School of Medicine, Stanford
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19
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Mazzochette EA, Nekimken AL, Loizeau F, Whitworth J, Huynh B, Goodman MB, Pruitt BL. The tactile receptive fields of freely moving Caenorhabditis elegans nematodes. Integr Biol (Camb) 2018; 10:450-463. [PMID: 30027970 PMCID: PMC6168290 DOI: 10.1039/c8ib00045j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sensory neurons embedded in skin are responsible for the sense of touch. In humans and other mammals, touch sensation depends on thousands of diverse somatosensory neurons. By contrast, Caenorhabditis elegans nematodes have six gentle touch receptor neurons linked to simple behaviors. The classical touch assay uses an eyebrow hair to stimulate freely moving C. elegans, evoking evasive behavioral responses. This assay has led to the discovery of genes required for touch sensation, but does not provide control over stimulus strength or position. Here, we present an integrated system for performing automated, quantitative touch assays that circumvents these limitations and incorporates automated measurements of behavioral responses. The Highly Automated Worm Kicker (HAWK) unites a microfabricated silicon force sensor holding a glass bead forming the contact surface and video analysis with real-time force and position control. Using this system, we stimulated animals along the anterior-posterior axis and compared responses in wild-type and spc-1(dn) transgenic animals, which have a touch defect due to expression of a dominant-negative α-spectrin protein fragment. As expected from prior studies, delivering large stimuli anterior and posterior to the mid-point of the body evoked a reversal and a speed-up, respectively. The probability of evoking a response of either kind depended on stimulus strength and location; once initiated, the magnitude and quality of both reversal and speed-up behavioral responses were uncorrelated with stimulus location, strength, or the absence or presence of the spc-1(dn) transgene. Wild-type animals failed to respond when the stimulus was applied near the mid-point. These results show that stimulus strength and location govern the activation of a characteristic motor program and that the C. elegans body surface consists of two receptive fields separated by a gap.
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Affiliation(s)
- E A Mazzochette
- Department of Electrical Engineering, Stanford University, 94305, USA
| | - A L Nekimken
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA
| | - F Loizeau
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - J Whitworth
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - B Huynh
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - M B Goodman
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA
| | - B L Pruitt
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA and Department of Bioengineering, Stanford University, 94305, USA and Department of Mechanical Engineering, University of California, Santa Barbara, 93106, USA.
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20
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Affiliation(s)
- Sierra K Lear
- Chemical & Biomolecular Engineering, Tulane University, New Orleans, LA
| | - Alakananda Das
- Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Miriam B Goodman
- Molecular and Cellular Physiology, Stanford University, Stanford, CA
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21
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Lay A, Siefe C, Fischer S, Mehlenbacher RD, Ke F, Mao WL, Alivisatos AP, Goodman MB, Dionne JA. Bright, Mechanosensitive Upconversion with Cubic-Phase Heteroepitaxial Core-Shell Nanoparticles. Nano Lett 2018; 18:4454-4459. [PMID: 29927609 PMCID: PMC6613353 DOI: 10.1021/acs.nanolett.8b01535] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Lanthanide-doped nanoparticles are an emerging class of optical sensors, exhibiting sharp emission peaks, high signal-to-noise ratio, photostability, and a ratiometric color response to stress. The same centrosymmetric crystal field environment that allows for high mechanosensitivity in the cubic-phase (α), however, contributes to low upconversion quantum yield (UCQY). In this work, we engineer brighter mechanosensitive upconverters using a core-shell geometry. Sub-25 nm α-NaYF4:Yb,Er cores are shelled with an optically inert surface passivation layer of ∼4.5 nm thickness. Using different shell materials, including NaGdF4, NaYF4, and NaLuF4, we study how compressive to tensile strain influences the nanoparticles' imaging and sensing properties. All core-shell nanoparticles exhibit enhanced UCQY, up to 0.14% at 150 W/cm2, which rivals the efficiency of unshelled hexagonal-phase (β) nanoparticles. Additionally, strain at the core-shell interface can tune mechanosensitivity. In particular, the compressive Gd shell results in the largest color response from yellow-green to orange or, quantitatively, a change in the red to green ratio of 12.2 ± 1.2% per GPa. For all samples, the ratiometric readouts are consistent over three pressure cycles from ambient to 5 GPa. Therefore, heteroepitaxial shelling significantly improves signal brightness without compromising the core's mechano-sensing capabilities and further, promotes core-shell cubic-phase nanoparticles as upcoming in vivo and in situ optical sensors.
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Affiliation(s)
| | | | | | | | | | | | - A Paul Alivisatos
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Kavli Energy NanoScience Institute , Berkeley , California 94720 , United States
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology , Stanford University , Stanford , California 94305 , United States
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22
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Fehlauer H, Nekimken AL, Kim AA, Pruitt BL, Goodman MB, Krieg M. Using a Microfluidics Device for Mechanical Stimulation and High Resolution Imaging of C. elegans. J Vis Exp 2018. [PMID: 29553526 DOI: 10.3791/56530] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
One central goal of mechanobiology is to understand the reciprocal effect of mechanical stress on proteins and cells. Despite its importance, the influence of mechanical stress on cellular function is still poorly understood. In part, this knowledge gap exists because few tools enable simultaneous deformation of tissue and cells, imaging of cellular activity in live animals, and efficient restriction of motility in otherwise highly mobile model organisms, such as the nematode Caenorhabditis elegans. The small size of C. elegans makes them an excellent match to microfluidics-based research devices, and solutions for immobilization have been presented using microfluidic devices. Although these devices allow for high-resolution imaging, the animal is fully encased in polydimethylsiloxane (PDMS) and glass, limiting physical access for delivery of mechanical force or electrophysiological recordings. Recently, we created a device that integrates pneumatic actuators with a trapping design that is compatible with high-resolution fluorescence microscopy. The actuation channel is separated from the worm-trapping channel by a thin PDMS diaphragm. This diaphragm is deflected into the side of a worm by applying pressure from an external source. The device can target individual mechanosensitive neurons. The activation of these neurons is imaged at high-resolution with genetically-encoded calcium indicators. This article presents the general method using C. elegans strains expressing calcium-sensitive activity indicator (GCaMP6s) in their touch receptor neurons (TRNs). The method, however, is not limited to TRNs nor to calcium sensors as a probe, but can be expanded to other mechanically-sensitive cells or sensors.
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Affiliation(s)
- Holger Fehlauer
- Department of Molecular and Cellular Physiology, Stanford University
| | - Adam L Nekimken
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University
| | - Anna A Kim
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University
| | - Beth L Pruitt
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University; Department of Bioengineering, Stanford University;
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University;
| | - Michael Krieg
- Group of Neurophotonics and Mechanical Systems Biology, The Institute of Photonic Sciences (ICFO);
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23
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Goodman MB, Fehlauer H. Fully Automated Ultrasound-Based Touch Assay for Small Model Organisms. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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24
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Katta S, Vásquez V, Goodman MB. The Dynamics of Somatosensory Mechanotransduction in C. elegans Touch Receptor Neurons. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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25
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Fechner S, Loizeau F, Nekimken AL, D'Alessandro I, Pruitt BL, Goodman MB. Characterization of DEGT-1: A DEG/ENaC/ASIC Ion Channel Subunit Involved in Touch Sensation. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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26
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Lay A, Wang DS, Wisser MD, Mehlenbacher RD, Lin Y, Goodman MB, Mao WL, Dionne JA. Upconverting Nanoparticles as Optical Sensors of Nano- to Micro-Newton Forces. Nano Lett 2017; 17:4172-4177. [PMID: 28608687 PMCID: PMC6589185 DOI: 10.1021/acs.nanolett.7b00963] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Mechanical forces affect a myriad of processes, from bone growth to material fracture to touch-responsive robotics. While nano- to micro-Newton forces are prevalent at the microscopic scale, few methods have the nanoscopic size and signal stability to measure them in vivo or in situ. Here, we develop an optical force-sensing platform based on sub-25 nm NaYF4 nanoparticles (NPs) doped with Yb3+, Er3+, and Mn2+. The lanthanides Yb3+ and Er3+ enable both photoluminescence and upconversion, while the energetically coupled d-metal Mn2+ adds force tunability through its crystal field sensitivity. Using a diamond anvil cell to exert up to 3.5 GPa pressure or ∼10 μN force per particle, we track stress-induced spectral responses. The red (660 nm) to green (520, 540 nm) emission ratio varies linearly with pressure, yielding an observed color change from orange to red for α-NaYF4 and from yellow-green to green for d-metal optimized β-NaYF4 when illuminated in the near infrared. Consistent readouts are recorded over multiple pressure cycles and hours of illumination. With the nanoscopic size, a dynamic range of 100 nN to 10 μN, and photostability, these nanoparticles lay the foundation for visualizing dynamic mechanical processes, such as stress propagation in materials and force signaling in organisms.
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Affiliation(s)
- Alice Lay
- Department of Applied Physics, Stanford University, Stanford, CA 94305
- ;
| | - Derek S. Wang
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305
| | - Michael D. Wisser
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305
| | - Randy D. Mehlenbacher
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305
| | - Yu Lin
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Wendy L. Mao
- Department of Geological Sciences, Stanford University, Stanford, CA 94305
| | - Jennifer A. Dionne
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305
- ;
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27
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Nekimken AL, Mazzochette EA, Goodman MB, Pruitt BL. Forces applied during classical touch assays for Caenorhabditis elegans. PLoS One 2017; 12:e0178080. [PMID: 28542494 PMCID: PMC5438190 DOI: 10.1371/journal.pone.0178080] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 05/06/2017] [Indexed: 12/03/2022] Open
Abstract
For decades, Caenorhabditis elegans roundworms have been used to study the sense of touch, and this work has been facilitated by a simple behavioral assay for touch sensation. To perform this classical assay, an experimenter uses an eyebrow hair to gently touch a moving worm and observes whether or not the worm reverses direction. We used two experimental approaches to determine the manner and moment of contact between the eyebrow hair tool and freely moving animals and the forces delivered by the classical assay. Using high-speed video (2500 frames/second), we found that typical stimulus delivery events include a brief moment when the hair is contact with the worm's body and not the agar substrate. To measure the applied forces, we measured forces generated by volunteers mimicking the classical touch assay by touching a calibrated microcantilever. The mean (61 μN) and median forces (26 μN) were more than ten times higher than the 2-μN force known to saturate the probability of evoking a reversal in adult C. elegans. We also considered the eyebrow hairs as an additional source of variation. The stiffness of the sampled eyebrow hairs varied between 0.07 and 0.41 N/m and was correlated with the free length of hair. Collectively, this work establishes that the classical touch assay applies enough force to saturate the probability of evoking reversals in adult C. elegans in spite of its variability among trials and experimenters and that increasing the free length of the hair can decrease the applied force.
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Affiliation(s)
- Adam L. Nekimken
- Mechanical Engineering Department, Stanford University, Stanford, California, United States of America
| | - Eileen A. Mazzochette
- Electrical Engineering Department, Stanford University, Stanford, California, United States of America
| | - Miriam B. Goodman
- Mechanical Engineering Department, Stanford University, Stanford, California, United States of America
- Molecular and Cellular Physiology Department, Stanford University, Stanford, California, United States of America
| | - Beth L. Pruitt
- Mechanical Engineering Department, Stanford University, Stanford, California, United States of America
- Molecular and Cellular Physiology Department, Stanford University, Stanford, California, United States of America
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28
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Nekimken AL, Fehlauer H, Kim AA, Manosalvas-Kjono SN, Ladpli P, Memon F, Gopisetty D, Sanchez V, Goodman MB, Pruitt BL, Krieg M. Pneumatic stimulation of C. elegans mechanoreceptor neurons in a microfluidic trap. Lab Chip 2017; 17:1116-1127. [PMID: 28207921 PMCID: PMC5360562 DOI: 10.1039/c6lc01165a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
New tools for applying force to animals, tissues, and cells are critically needed in order to advance the field of mechanobiology, as few existing tools enable simultaneous imaging of tissue and cell deformation as well as cellular activity in live animals. Here, we introduce a novel microfluidic device that enables high-resolution optical imaging of cellular deformations and activity while applying precise mechanical stimuli to the surface of the worm's cuticle with a pneumatic pressure reservoir. To evaluate device performance, we compared analytical and numerical simulations conducted during the design process to empirical measurements made with fabricated devices. Leveraging the well-characterized touch receptor neurons (TRNs) with an optogenetic calcium indicator as a model mechanoreceptor neuron, we established that individual neurons can be stimulated and that the device can effectively deliver steps as well as more complex stimulus patterns. This microfluidic device is therefore a valuable platform for investigating the mechanobiology of living animals and their mechanosensitive neurons.
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Affiliation(s)
- Adam L Nekimken
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA. and Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Holger Fehlauer
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Anna A Kim
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA. and Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Purim Ladpli
- Department of Aeronautics and Astronautics, Stanford University, Stanford, California, USA
| | - Farah Memon
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Divya Gopisetty
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Veronica Sanchez
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA.
| | - Miriam B Goodman
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA. and Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA. and Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA. and Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA.
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29
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Fechner S, Loizeau F, Nekimken AL, Pruitt BL, Goodman MB. Subunits that form Trimeric DEG/ENaC Mechano-Electrical Transduction Channels in Touch Receptor Neurons. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.2964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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30
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Krieg M, Stuehmer J, Cueva JG, Fetter R, Spilker K, Cremers D, Shen K, Dunn AR, Goodman MB. Tau Like Proteins Reduce Torque Generation in Microtubule Bundles. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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31
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Krieg M, Stühmer J, Cueva JG, Fetter R, Spilker K, Cremers D, Shen K, Dunn AR, Goodman MB. Genetic defects in β-spectrin and tau sensitize C. elegans axons to movement-induced damage via torque-tension coupling. eLife 2017; 6. [PMID: 28098556 PMCID: PMC5298879 DOI: 10.7554/elife.20172] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 01/17/2017] [Indexed: 12/24/2022] Open
Abstract
Our bodies are in constant motion and so are the neurons that invade each tissue. Motion-induced neuron deformation and damage are associated with several neurodegenerative conditions. Here, we investigated the question of how the neuronal cytoskeleton protects axons and dendrites from mechanical stress, exploiting mutations in UNC-70 β-spectrin, PTL-1 tau/MAP2-like and MEC-7 β-tubulin proteins in Caenorhabditis elegans. We found that mechanical stress induces supercoils and plectonemes in the sensory axons of spectrin and tau double mutants. Biophysical measurements, super-resolution, and electron microscopy, as well as numerical simulations of neurons as discrete, elastic rods provide evidence that a balance of torque, tension, and elasticity stabilizes neurons against mechanical deformation. We conclude that the spectrin and microtubule cytoskeletons work in combination to protect axons and dendrites from mechanical stress and propose that defects in β-spectrin and tau may sensitize neurons to damage. DOI:http://dx.doi.org/10.7554/eLife.20172.001
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Affiliation(s)
- Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States.,Department of Chemical Engineering, Stanford University, Stanford, United States
| | - Jan Stühmer
- Department of Informatics, Technical University of Munich, , Germany
| | - Juan G Cueva
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Richard Fetter
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Kerri Spilker
- Department of Biology, Stanford University, Stanford, United States
| | - Daniel Cremers
- Department of Informatics, Technical University of Munich, , Germany
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, United States
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, United States
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
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32
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Lockhead D, Schwarz EM, O'Hagan R, Bellotti S, Krieg M, Barr MM, Dunn AR, Sternberg PW, Goodman MB. The tubulin repertoire of C. elegans sensory neurons and its context-dependent role in process outgrowth. Mol Biol Cell 2016; 27:mbc.E16-06-0473. [PMID: 27654945 PMCID: PMC5170555 DOI: 10.1091/mbc.e16-06-0473] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/12/2016] [Accepted: 09/15/2016] [Indexed: 12/21/2022] Open
Abstract
Microtubules contribute to many cellular processes, including transport, signaling, and chromosome separation during cell division (Kapitein and Hoogenraad, 2015). They are comprised of αβ-tubulin heterodimers arranged into linear protofilaments and assembled into tubes. Eukaryotes express multiple tubulin isoforms (Gogonea et al., 1999), and there has been a longstanding debate as to whether the isoforms are redundant or perform specialized roles as part of a tubulin code (Fulton and Simpson, 1976). Here, we use the well-characterized touch receptor neurons (TRNs) of Caenorhabditis elegans to investigate this question, through genetic dissection of process outgrowth both in vivo and in vitro With single-cell RNA-seq, we compare transcription profiles for TRNs with those of two other sensory neurons, and present evidence that each sensory neuron expresses a distinct palette of tubulin genes. In the TRNs, we analyze process outgrowth and show that four tubulins (tba-1, tba-2, tbb-1, and tbb-2) function partially or fully redundantly, while two others (mec-7 and mec-12) perform specialized, context-dependent roles. Our findings support a model in which sensory neurons express overlapping subsets of tubulin genes whose functional redundancy varies between cell types and in vivo and in vitro contexts.
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Affiliation(s)
- Dean Lockhead
- *Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Erich M Schwarz
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Robert O'Hagan
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Sebastian Bellotti
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Michael Krieg
- *Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Maureen M Barr
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305 Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Paul W Sternberg
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Miriam B Goodman
- *Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
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Glauser DA, Goodman MB. Molecules empowering animals to sense and respond to temperature in changing environments. Curr Opin Neurobiol 2016; 41:92-98. [PMID: 27657982 DOI: 10.1016/j.conb.2016.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/17/2016] [Accepted: 09/05/2016] [Indexed: 11/25/2022]
Abstract
Adapting behavior to thermal cues is essential for animal growth and survival. Indeed, each and every biological and biochemical process is profoundly affected by temperature and its extremes can cause irreversible damage. Hence, animals have developed thermotransduction mechanisms to detect and encode thermal information in the nervous system and acclimation mechanisms to finely tune their response over different timescales. While temperature-gated TRP channels are the best described class of temperature sensors, recent studies highlight many new candidates, including ionotropic and metabotropic receptors. Here, we review recent findings in vertebrate and invertebrate models, which highlight and substantiate the role of new candidate molecular thermometers and reveal intracellular signaling mechanisms implicated in thermal acclimation at the behavioral and cellular levels.
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Affiliation(s)
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
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Abstract
Organisms as diverse as microbes, roundworms, insects, and mammals detect and respond to applied force. In animals, this ability depends on ionotropic force receptors, known as mechanoelectrical transduction (MeT) channels, that are expressed by specialized mechanoreceptor cells embedded in diverse tissues and distributed throughout the body. These cells mediate hearing, touch, and proprioception and play a crucial role in regulating organ function. Here, we attempt to integrate knowledge about the architecture of mechanoreceptor cells and their sensory organs with principles of cell mechanics, and we consider how engulfing tissues contribute to mechanical filtering. We address progress in the quest to identify the proteins that form MeT channels and to understand how these channels are gated. For clarity and convenience, we focus on sensory mechanobiology in nematodes, fruit flies, and mice. These themes are emphasized: asymmetric responses to applied forces, which may reflect anisotropy of the structure and mechanics of sensory mechanoreceptor cells, and proteins that function as MeT channels, which appear to have emerged many times through evolution.
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Affiliation(s)
- Samata Katta
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
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Chalasani SH, Chronis N, Tsunozaki M, Gray JM, Ramot D, Goodman MB, Bargmann CI. Corrigendum: Dissecting a circuit for olfactory behaviour in Caenorhabditis elegans. Nature 2016; 533:130. [PMID: 26789243 DOI: 10.1038/nature16515] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
A trio of papers has resolved an outstanding controversy regarding the function of Merkel cells and their afferent nerve fiber partners. Merkel cells sense mechanical stimuli (through Piezo2), fire action potentials, and are sufficient to activate downstream sensory neurons.
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Affiliation(s)
- Valeria Vásquez
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Gregory Scherrer
- Departments of Anesthesiology, Perioperative and Pain Medicine and Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
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Kelley M, Yochem J, Krieg M, Calixto A, Heiman MG, Kuzmanov A, Meli V, Chalfie M, Goodman MB, Shaham S, Frand A, Fay DS. FBN-1, a fibrillin-related protein, is required for resistance of the epidermis to mechanical deformation during C. elegans embryogenesis. eLife 2015; 4. [PMID: 25798732 PMCID: PMC4395870 DOI: 10.7554/elife.06565] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/20/2015] [Indexed: 12/19/2022] Open
Abstract
During development, biomechanical forces contour the body and provide shape to internal organs. Using genetic and molecular approaches in combination with a FRET-based tension sensor, we characterized a pulling force exerted by the elongating pharynx (foregut) on the anterior epidermis during C. elegans embryogenesis. Resistance of the epidermis to this force and to actomyosin-based circumferential constricting forces is mediated by FBN-1, a ZP domain protein related to vertebrate fibrillins. fbn-1 was required specifically within the epidermis and FBN-1 was expressed in epidermal cells and secreted to the apical surface as a putative component of the embryonic sheath. Tiling array studies indicated that fbn-1 mRNA processing requires the conserved alternative splicing factor MEC-8/RBPMS. The conserved SYM-3/FAM102A and SYM-4/WDR44 proteins, which are linked to protein trafficking, function as additional components of this network. Our studies demonstrate the importance of the apical extracellular matrix in preventing mechanical deformation of the epidermis during development. DOI:http://dx.doi.org/10.7554/eLife.06565.001 For an animal embryo to develop, its cells must organize themselves into tissues and organs. For example, skin and the lining of internal organs—such as the lungs and gut—are made from cells called epithelial cells, which are tightly linked to form flat sheets. In a microscopic worm called Caenorhabditis elegans, the outermost layer of epithelial cells (called the epidermis) forms over the surface of the embryo early on in embryonic development. Shortly afterwards, the embryonic epidermis experiences powerful contractions along the surface of the embryo. The force generated by these contractions converts the embryo from an oval shape to a roughly cylindrical form. These contractions also squeeze the internal tissues and organs, which correspondingly elongate along with the epidermis. It has been known for decades that such ‘mechanical’ forces are important for the normal development of embryos. However, it remains poorly understood how these forces generate tissues and organs of the proper shape—partly because it is difficult to measure forces in living embryos. It is also not clear how the mechanical properties of specific tissues are controlled. Now, Kelley, Yochem, Krieg et al. have analyzed the development of C. elegans' embryos and discovered a novel mechanical interplay between the feeding organ (called the pharynx) and the worm's epidermis. The experiments involved studying several mutant worms that perturb epidermal contractions and disrupt the attachment of the pharynx to the epidermis. These studies suggested that the pharynx exerts a strong inward pulling force on the epidermis during development. Using recently developed methods, Kelley, Yochem, Krieg et al. then measured mechanical forces within intact worm embryos and demonstrated that greater forces were experienced in cells that were being pulled by the pharynx. Kelley, Yochem, Krieg et al. further analyzed how the epidermis normally resists this pulling force from the pharynx and implicated a protein called FBN-1. This worm protein is structurally related to a human protein that is affected in people with a disorder called Marfan Syndrome. Worm embryos without the FBN-1 protein become severely deformed because they are unable to withstand mechanical forces at the epidermis. FBN-1 is normally synthesized and then transported to the outside of the worm embryo by epidermal cells, where it is thought to assemble into a meshwork of long fibers. This provides a strong scaffold that attaches to the epidermis to prevent the epidermis from undergoing excessive deformation while it experiences mechanical forces. The work of Kelley, Yochem, Krieg et al. provides an opportunity to understand how FBN-1 and other fiber-forming proteins are produced and transported to the cell surface. Moreover, these findings may have implications for human diseases and birth defects that result from an inability of tissues to respond appropriately to mechanical forces. DOI:http://dx.doi.org/10.7554/eLife.06565.002
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Affiliation(s)
- Melissa Kelley
- Department of Molecular Biology, University of Wyoming, Laramie, United States
| | - John Yochem
- Department of Molecular Biology, University of Wyoming, Laramie, United States
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Andrea Calixto
- Department of Biological Sciences, Columbia University, New York, United States
| | - Maxwell G Heiman
- Department of Genetics, Harvard Medical School, Boston Children's Hospital, Boston, United States
| | - Aleksandra Kuzmanov
- Department of Molecular Biology, University of Wyoming, Laramie, United States
| | - Vijaykumar Meli
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, United States
| | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, United States
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, New York, United States
| | - Alison Frand
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, United States
| | - David S Fay
- Department of Molecular Biology, University of Wyoming, Laramie, United States
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Abstract
The sense of touch informs us of the physical properties of our surroundings and is a critical aspect of communication. Before touches are perceived, mechanical signals are transmitted quickly and reliably from the skin's surface to mechano-electrical transduction channels embedded within specialized sensory neurons. We are just beginning to understand how soft tissues participate in force transmission and how they are deformed. Here, we review empirical and theoretical studies of single molecules and molecular ensembles thought to be involved in mechanotransmission and apply the concepts emerging from this work to the sense of touch. We focus on the nematode Caenorhabditis elegans as a well-studied model for touch sensation in which mechanics can be studied on the molecular, cellular, and systems level. Finally, we conclude that force transmission is an emergent property of macromolecular cellular structures that mutually stabilize one another.
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Affiliation(s)
- Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
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Schild LC, Zbinden L, Bell HW, Yu YV, Sengupta P, Goodman MB, Glauser DA. The balance between cytoplasmic and nuclear CaM kinase-1 signaling controls the operating range of noxious heat avoidance. Neuron 2014; 84:983-96. [PMID: 25467982 DOI: 10.1016/j.neuron.2014.10.039] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2014] [Indexed: 12/12/2022]
Abstract
Through encounters with predators, competitors, and noxious stimuli, animals have evolved defensive responses that minimize injury and are essential for survival. Physiological adaptation modulates the stimulus intensities that trigger such nocifensive behaviors, but the molecular networks that define their operating range are largely unknown. Here, we identify a gain-of-function allele of the cmk-1 CaMKI gene in C. elegans and show that loss of the regulatory domain of the CaMKI enzyme produces thermal analgesia and shifts the operating range for nocifensive heat avoidance to higher temperatures. Such analgesia depends on nuclear CMK-1 signaling, while cytoplasmic CMK-1 signaling lowers the threshold for thermal avoidance. CMK-1 acts downstream of heat detection in thermal receptor neurons and controls neuropeptide release. Our results establish CaMKI as a key regulator of the operating range for nocifensive behaviors and suggest strategies for producing thermal analgesia through the regulation of CaMKI-dependent signaling.
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Affiliation(s)
- Lisa C Schild
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Laurie Zbinden
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Harold W Bell
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, USA
| | - Yanxun V Yu
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, USA
| | - Piali Sengupta
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, USA
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford School of Medicine, Stanford, CA 94305, USA.
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Yu YV, Bell HW, Glauser D, Van Hooser SD, Goodman MB, Sengupta P. CaMKI-dependent regulation of sensory gene expression mediates experience-dependent plasticity in the operating range of a thermosensory neuron. Neuron 2014; 84:919-926. [PMID: 25467978 DOI: 10.1016/j.neuron.2014.10.046] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2014] [Indexed: 11/19/2022]
Abstract
Sensory adaptation represents a form of experience-dependent plasticity that allows neurons to retain high sensitivity over a broad dynamic range. The mechanisms by which sensory neuron responses are altered on different timescales during adaptation are unclear. The threshold for temperature-evoked activity in the AFD thermosensory neurons (T*(AFD)) in C. elegans is set by the cultivation temperature (T(c)) and regulated by intracellular cGMP levels. We find that T*(AFD) adapts on both short and long timescales upon exposure to temperatures warmer than T(c), and that prolonged exposure to warmer temperatures alters expression of AFD-specific receptor guanylyl cyclase genes. These temperature-regulated changes in gene expression are mediated by the CMK-1 CaMKI enzyme, which exhibits T(c)-dependent nucleocytoplasmic shuttling in AFD. Our results indicate that CaMKI-mediated changes in sensory gene expression contribute to long-term adaptation of T*(AFD), and suggest that similar temporally and mechanistically distinct phases may regulate the operating ranges of other sensory neurons.
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Affiliation(s)
- Yanxun V Yu
- Department of Biology, National Center for Behavioral Genomics Brandeis University Waltham, MA 02454
| | - Harold W Bell
- Department of Biology, National Center for Behavioral Genomics Brandeis University Waltham, MA 02454
| | - Dominique Glauser
- Department of Biology University of Fribourg Fribourg 1700, Switzerland
| | - Stephen D Van Hooser
- Department of Biology, National Center for Behavioral Genomics Brandeis University Waltham, MA 02454
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology Stanford University School of Medicine Palo Alto, CA 94305
| | - Piali Sengupta
- Department of Biology, National Center for Behavioral Genomics Brandeis University Waltham, MA 02454
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41
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Abstract
C. elegans detect and respond to diverse mechanical stimuli using neuronal circuitry that has been defined by decades of work by C. elegans researchers. In this WormMethods chapter, we review and comment on the techniques currently used to assess mechanosensory response. This methods review is intended both as an introduction for those new to the field and a convenient compendium for the expert. A brief discussion of commonly used mechanosensory assays is provided, along with a discussion of the neural circuits involved, consideration of critical protocol details, and references to the primary literature.
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Affiliation(s)
- Martin Chalfie
- Department of Biological Sciences, Columbia University, New York NY, USA.
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Wang D, O'Halloran D, Goodman MB. GCY-8, PDE-2, and NCS-1 are critical elements of the cGMP-dependent thermotransduction cascade in the AFD neurons responsible for C. elegans thermotaxis. ACTA ACUST UNITED AC 2014; 142:437-49. [PMID: 24081984 PMCID: PMC3787776 DOI: 10.1085/jgp.201310959] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Certain thermoreceptor neurons are sensitive to tiny thermal fluctuations (0.01°C or less) and maintain their sensitivity across a wide range of ambient temperatures through a process of adaptation, but understanding of the biochemical basis for this performance is rudimentary. Prior studies of the AFD thermoreceptor in Caenorhabditis elegans revealed a signaling cascade that depends on a trio of receptor guanylate cyclases (rGCs), GCY-8, GCY-18, and GCY-23, and gives rise to warming-activated thermoreceptor currents (ThRCs) carried by cyclic GMP–gated ion channels. The threshold for ThRC activation adapts to the ambient temperature through an unknown calcium-dependent process. Here, we use in vivo whole-cell patch-clamp recording from AFD to show that loss of GCY-8, but not of GCY-18 or GCY-23, reduces or eliminates ThRCs, identifying this rGC as a crucial signaling element. To learn more about thermotransduction and adaptation, we used behavioral screens and analysis of gene expression patterns to identify phosphodiesterases (PDEs) likely to contribute to thermotransduction. Deleting PDE-2 decouples the threshold for ThRC activation from ambient temperature, altering adaptation. We provide evidence that the conserved neuronal calcium sensor 1 protein also regulates the threshold for ThRC activation and propose a signaling network to account for ThRC activation and adaptation. Because PDEs play essential roles in diverse biological processes, including vertebrate phototransduction and olfaction, and regulation of smooth muscle contractility and cardiovascular function, this study has broad implications for understanding how extraordinary sensitivity and dynamic range is achieved in cyclic nucleotide–based signaling networks.
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Affiliation(s)
- Dong Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
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Richardson CE, Spilker KA, Cueva JG, Perrino J, Goodman MB, Shen K. PTRN-1, a microtubule minus end-binding CAMSAP homolog, promotes microtubule function in Caenorhabditis elegans neurons. eLife 2014; 3:e01498. [PMID: 24569477 PMCID: PMC3932522 DOI: 10.7554/elife.01498] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In neuronal processes, microtubules (MTs) provide structural support and serve as tracks for molecular motors. While it is known that neuronal MTs are more stable than MTs in non-neuronal cells, the molecular mechanisms underlying this stability are not fully understood. In this study, we used live fluorescence microscopy to show that the C. elegans CAMSAP protein PTRN-1 localizes to puncta along neuronal processes, stabilizes MT foci, and promotes MT polymerization in neurites. Electron microscopy revealed that ptrn-1 null mutants have fewer MTs and abnormal MT organization in the PLM neuron. Animals grown with a MT depolymerizing drug caused synthetic defects in neurite branching in the absence of ptrn-1 function, indicating that PTRN-1 promotes MT stability. Further, ptrn-1 null mutants exhibited aberrant neurite morphology and synaptic vesicle localization that is partially dependent on dlk-1. Our results suggest that PTRN-1 represents an important mechanism for promoting MT stability in neurons. DOI:http://dx.doi.org/10.7554/eLife.01498.001 Microtubules are tiny tubular structures made from many copies of proteins called tubulins. Microtubules have a number of important roles inside cells: they are part of the cytoskeleton that provides structural support for the cell; they help to pull chromosomes apart during cell division; and they guide the trafficking of proteins and molecules around inside the cell. Most microtubules are relatively unstable, undergoing continuous dis-assembly and re-assembly in response to the needs of the cell. The microtubules in the branches of nerve cells are an exception, remaining relatively stable over time. Now Richardson et al. and, independently, Marcette et al., have shown that a protein called PTRN-1 has an important role in stabilizing the microtubules in the nerve cells of nematode worms. By tagging the PTRN-1 proteins with fluorescent molecules, Richardson et al. were able to show that these proteins were present along the length of the microtubules within the nerve cells. Further work showed that the PTRN-1 proteins stabilize the microtubule filaments within the branches of these nerve cells and also hold them in position. Richardson et al. also found that worms that had been genetically modified to prevent them from producing PTRN-1 failed to traffic certain molecules to the synapses between nerve cells. Moreover, these mutants also had problems with the branching of their nerve cells; however, these defects were relatively mild, which suggests that other molecules and proteins act in parallel with PTRN-1 to stabilize microtubules in nerve cells. Further work should be able to identify these factors and elucidate how they work together to stabilize the microtubules in nerve cells. DOI:http://dx.doi.org/10.7554/eLife.01498.002
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Abstract
This chapter describes four different protocols used to assay thermotaxis navigation behavior of single, or populations of, C. elegans hermaphrodites on spatial thermal gradients within the physiological temperature range (15-25°C). A method to assay avoidance of noxious temperatures is also described.
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Affiliation(s)
- Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford CA, USA.
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45
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Petzold BC, Park SJ, Mazzochette EA, Goodman MB, Pruitt BL. MEMS-based force-clamp analysis of the role of body stiffness in C. elegans touch sensation. Integr Biol (Camb) 2014; 5:853-64. [PMID: 23598612 DOI: 10.1039/c3ib20293c] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Touch is enabled by mechanoreceptor neurons in the skin and plays an essential role in our everyday lives, but is among the least understood of our five basic senses. Force applied to the skin deforms these neurons and activates ion channels within them. Despite the importance of the mechanics of the skin in determining mechanoreceptor neuron deformation and ultimately touch sensation, the role of mechanics in touch sensitivity is poorly understood. Here, we use the model organism Caenorhabditis elegans to directly test the hypothesis that body mechanics modulate touch sensitivity. We demonstrate a microelectromechanical system (MEMS)-based force clamp that can apply calibrated forces to freely crawling C. elegans worms and measure touch-evoked avoidance responses. This approach reveals that wild-type animals sense forces <1 μN and indentation depths <1 μm. We use both genetic manipulation of the skin and optogenetic modulation of body wall muscles to alter body mechanics. We find that small changes in body stiffness dramatically affect force sensitivity, while having only modest effects on indentation sensitivity. We investigate the theoretical body deformation predicted under applied force and conclude that local mechanical loads induce inward bending deformation of the skin to drive touch sensation in C. elegans.
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Affiliation(s)
- Bryan C Petzold
- Department of Mechanical Engineering, Stanford University School of Engineering, Stanford, California, USA
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Vásquez V, Krieg M, Lockhead D, Goodman MB. Phospholipids that contain polyunsaturated fatty acids enhance neuronal cell mechanics and touch sensation. Cell Rep 2014; 6:70-80. [PMID: 24388754 DOI: 10.1016/j.celrep.2013.12.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/18/2013] [Accepted: 12/06/2013] [Indexed: 12/01/2022] Open
Abstract
Mechanoelectrical transduction (MeT) channels embedded in neuronal cell membranes are essential for touch and proprioception. Little is understood about the interplay between native MeT channels and membrane phospholipids, in part because few techniques are available for altering plasma membrane composition in vivo. Here, we leverage genetic dissection, chemical complementation, and optogenetics to establish that arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, enhances touch sensation and mechanoelectrical transduction activity while incorporated into membrane phospholipids in C. elegans touch receptor neurons (TRNs). Because dynamic force spectroscopy reveals that AA modulates the mechanical properties of TRN plasma membranes, we propose that this polyunsaturated fatty acid (PUFA) is needed for MeT channel activity. These findings establish that polyunsaturated phospholipids are crucial determinants of both the biochemistry and mechanics of mechanoreceptor neurons and reinforce the idea that sensory mechanotransduction in animals relies on a cellular machine composed of both proteins and membrane lipids.
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Affiliation(s)
- Valeria Vásquez
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dean Lockhead
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Vasquez V, Krieg M, Lockhead D, Goodman MB. Omega 6 Polyunsaturated Fatty Acid-Containing Phospholipids Enhance Neuronal Cell Mechanics and Touch in C. Elegans. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.2544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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48
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Krieg M, Dunn AR, Goodman MB. B-Spectrin and the Mechanical Control of the Sense of Touch. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.2043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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49
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Goodman MB. Touch as a Matter of Fat: The Phospholipids and DEG/ENaC Channels Needed for Metazoan Touch Sensation. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.2385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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50
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Goodman MB. Deconstructing the Physical and Molecular Basis of Touch and Pain Sensation. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.2445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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