An hourglass circuit motif transforms a motor program via subcellularly localized muscle calcium signaling and contraction

  1. Steven R Sando  Is a corresponding author
  2. Nikhil Bhatla
  3. Eugene L Q Lee
  4. H Robert Horvitz  Is a corresponding author
  1. Massachusetts Institute of Technology, United States
  2. Miller Institute, Helen Wills Neuroscience Institute, University of California, Berkeley, United States

Abstract

Neural control of muscle function is fundamental to animal behavior. Many muscles can generate multiple distinct behaviors. Nonetheless, individual muscle cells are generally regarded as the smallest units of motor control. We report that muscle cells can alter behavior by contracting subcellularly. We previously discovered that noxious tastes reverse the net flow of particles through the C. elegans pharynx, a neuromuscular pump, resulting in spitting. We now show that spitting results from the subcellular contraction of the anterior region of the pm3 muscle cell. Subcellularly localized calcium increases accompany this contraction. Spitting is controlled by an 'hourglass' circuit motif: parallel neural pathways converge onto a single motor neuron that differentially controls multiple muscles and the critical subcellular muscle compartment. We conclude that subcellular muscle units enable modulatory motor control and propose that subcellular muscle contraction is a fundamental mechanism by which neurons can reshape behavior.

Data availability

All numerical data and analyses generated during this study are included in the manuscript and supporting files. Each figure and figure supplement is accompanied by a source data file that includes all numerical data used to generate that figure. This includes all excel files, all matlab data files and figures, all statistical analyses, and the .svg (scalable vector graphic) file used to generate each figure.All custom Matlab scripts used in data analysis and the sequences of all plasmids generated in this study are also included in separate source data files.In addition, all raw imaging data (i.e., confocal micrographs, calcium imaging videos, and all high-speed behavioral videos) are available for download on FigShare (doi: 10.6084/m9.figshare.c.5485554).

The following data sets were generated

Article and author information

Author details

  1. Steven R Sando

    Biology, Massachusetts Institute of Technology, Cambridge, United States
    For correspondence
    srsando@mit.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1101-9810
  2. Nikhil Bhatla

    Molecular and Cellular Biology, Miller Institute, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Eugene L Q Lee

    Biology, Massachusetts Institute of Technology, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4725-4959
  4. H Robert Horvitz

    Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
    For correspondence
    horvitz@mit.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9964-9613

Funding

National Institutes of Health (T32GM007287)

  • Steven R Sando

National Institutes of Health (GM024663)

  • Steven R Sando
  • Nikhil Bhatla
  • H Robert Horvitz

McGovern Institute (Friends of the McGovern Institute Fellowship)

  • Steven R Sando
  • Eugene L Q Lee

Lord Foundation (Lord Foundation Fellowship)

  • Steven R Sando

National Science Foundation (Graduate Research Fellowship)

  • Nikhil Bhatla

Agency for Science, Technology and Research (National Science Scholarship)

  • Eugene L Q Lee

Howard Hughes Medical Institute

  • H Robert Horvitz

Miller Institute (Miller Institute Research Fellowship)

  • Nikhil Bhatla

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Manuel Zimmer, Research Institute of Molecular Pathology, Vienna Biocenter and University of Vienna, Austria

Publication history

  1. Received: May 26, 2020
  2. Accepted: June 26, 2021
  3. Accepted Manuscript published: July 2, 2021 (version 1)
  4. Version of Record published: August 3, 2021 (version 2)

Copyright

© 2021, Sando et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 1,701
    Page views
  • 227
    Downloads
  • 2
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Steven R Sando
  2. Nikhil Bhatla
  3. Eugene L Q Lee
  4. H Robert Horvitz
(2021)
An hourglass circuit motif transforms a motor program via subcellularly localized muscle calcium signaling and contraction
eLife 10:e59341.
https://doi.org/10.7554/eLife.59341
  1. Further reading

Further reading

    1. Neuroscience
    Jingyi Guo Fuglstad, Pearl Saldanha ... Jonathan R Whitlock
    Tools and Resources Updated

    Recording technologies for rodents have seen huge advances in the last decade, allowing users to sample thousands of neurons simultaneously from multiple brain regions. This has prompted the need for digital tool kits to aid in curating anatomical data, however, existing tools either provide limited functionalities or require users to be proficient in coding to use them. To address this we created HERBS (Histological E-data Registration in rodent Brain Spaces), a comprehensive new tool for rodent users that offers a broad range of functionalities through a user-friendly graphical user interface. Prior to experiments, HERBS can be used to plan coordinates for implanting electrodes, targeting viral injections or tracers. After experiments, users can register recording electrode locations (e.g. Neuropixels and tetrodes), viral expression, or other anatomical features, and visualize the results in 2D or 3D. Additionally, HERBS can delineate labeling from multiple injections across tissue sections and obtain individual cell counts.Regional delineations in HERBS are based either on annotated 3D volumes from the Waxholm Space Atlas of the Sprague Dawley Rat Brain or the Allen Mouse Brain Atlas, though HERBS can work with compatible volume atlases from any species users wish to install. HERBS allows users to scroll through the digital brain atlases and provides custom-angle slice cuts through the volumes, and supports free-transformation of tissue sections to atlas slices. Furthermore, HERBS allows users to reconstruct a 3D brain mesh with tissue from individual animals. HERBS is a multi-platform open-source Python package that is available on PyPI and GitHub, and is compatible with Windows, macOS, and Linux operating systems.

    1. Neuroscience
    Nathaniel J Himmel, Akira Sakurai ... Daniel N Cox
    Research Article Updated

    Individual sensory neurons can be tuned to many stimuli, each driving unique, stimulus-relevant behaviors, and the ability of multimodal nociceptor neurons to discriminate between potentially harmful and innocuous stimuli is broadly important for organismal survival. Moreover, disruptions in the capacity to differentiate between noxious and innocuous stimuli can result in neuropathic pain. Drosophila larval class III (CIII) neurons are peripheral noxious cold nociceptors and innocuous touch mechanosensors; high levels of activation drive cold-evoked contraction (CT) behavior, while low levels of activation result in a suite of touch-associated behaviors. However, it is unknown what molecular factors underlie CIII multimodality. Here, we show that the TMEM16/anoctamins subdued and white walker (wwk; CG15270) are required for cold-evoked CT, but not for touch-associated behavior, indicating a conserved role for anoctamins in nociception. We also evidence that CIII neurons make use of atypical depolarizing chloride currents to encode cold, and that overexpression of ncc69—a fly homologue of NKCC1—results in phenotypes consistent with neuropathic sensitization, including behavioral sensitization and neuronal hyperexcitability, making Drosophila CIII neurons a candidate system for future studies of the basic mechanisms underlying neuropathic pain.