High-throughput synapse-resolving two-photon fluorescence microendoscopy for deep-brain volumetric imaging in vivo

  1. Guanghan Meng
  2. Yajie Liang
  3. Sarah Sarsfield
  4. Wan-chen Jiang
  5. Rongwen Lu
  6. Joshua Tate Dudman
  7. Yeka Aponte
  8. Na Ji  Is a corresponding author
  1. University of California, Berkeley, United States
  2. Janelia Research Campus, Howard Hughes Medical Institute, United States
  3. National Institute on Drug Abuse, United States
  4. Johns Hopkins University School of Medicine, United States

Abstract

Optical imaging has become a powerful tool for studying brains in vivo. The opacity of adult brains makes microendoscopy, with an optical probe such as a gradient index (GRIN) lens embedded into brain tissue to provide optical relay, the method of choice for imaging neurons and neural activity in deeply buried brain structures. Incorporating a Bessel focus scanning module into two-photon fluorescence microendoscopy, we extended the excitation focus axially and improved its lateral resolution. Scanning the Bessel focus in 2D, we imaged volumes of neurons at high-throughput while resolving fine structures such as synaptic terminals. We applied this approach to the volumetric anatomical imaging of dendritic spines and axonal boutons in the mouse hippocampus, and functional imaging of GABAergic neurons in the mouse lateral hypothalamus in vivo.

Data availability

Almost all data needed to evaluate the conclusions in the paper are present in the paper or the supplementary materials; Raw image data for Figs. 2, 4 & 9 are available from Dryad, 10.5061/dryad.pr4t978

The following data sets were generated

Article and author information

Author details

  1. Guanghan Meng

    Department of Physics, University of California, Berkeley, Berkeley, United States
    Competing interests
    No competing interests declared.
  2. Yajie Liang

    Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
    Competing interests
    No competing interests declared.
  3. Sarah Sarsfield

    Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse, Baltimore, United States
    Competing interests
    No competing interests declared.
  4. Wan-chen Jiang

    Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
    Competing interests
    No competing interests declared.
  5. Rongwen Lu

    Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
    Competing interests
    Rongwen Lu, The Bessel focus scanning intellectual property has been licensed to Thorlabs, Inc. by HHMI.
  6. Joshua Tate Dudman

    Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4436-1057
  7. Yeka Aponte

    Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5967-2579
  8. Na Ji

    Department of Physics, University of California, Berkeley, Berkeley, United States
    For correspondence
    jina@berkeley.edu
    Competing interests
    Na Ji, The Bessel focus scanning intellectual property has been licensed to Thorlabs, Inc. by HHMI.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5527-1663

Funding

Howard Hughes Medical Institute

  • Guanghan Meng
  • Yajie Liang
  • Wan-chen Jiang
  • Rongwen Lu
  • Joshua Tate Dudman
  • Na Ji

National Institute of Neurological Disorders and Stroke

  • Guanghan Meng
  • Na Ji

National Institute on Drug Abuse

  • Sarah Sarsfield
  • Yeka Aponte

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

Ethics

Animal experimentation: All animal experiments were conducted according to the United States National Institutes of Health guidelines for animal research. Procedures and protocols were approved by the Institutional Animal Care and Use Committee at Janelia Research Campus, Howard Hughes Medical Institute (protocol number: 16-147)

Reviewing Editor

  1. David Kleinfeld, University of California, San Diego, United States

Publication history

  1. Received: August 5, 2018
  2. Accepted: December 20, 2018
  3. Accepted Manuscript published: January 3, 2019 (version 1)
  4. Accepted Manuscript updated: January 4, 2019 (version 2)
  5. Version of Record published: January 18, 2019 (version 3)

Copyright

© 2019, Meng 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

  • 9,836
    Page views
  • 1,480
    Downloads
  • 57
    Citations

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

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. Guanghan Meng
  2. Yajie Liang
  3. Sarah Sarsfield
  4. Wan-chen Jiang
  5. Rongwen Lu
  6. Joshua Tate Dudman
  7. Yeka Aponte
  8. Na Ji
(2019)
High-throughput synapse-resolving two-photon fluorescence microendoscopy for deep-brain volumetric imaging in vivo
eLife 8:e40805.
https://doi.org/10.7554/eLife.40805

Further reading

    1. Neuroscience
    Brian D Mueller, Sean A Merrill ... Erik M Jorgensen
    Research Article Updated

    Activation of voltage-gated calcium channels at presynaptic terminals leads to local increases in calcium and the fusion of synaptic vesicles containing neurotransmitter. Presynaptic output is a function of the density of calcium channels, the dynamic properties of the channel, the distance to docked vesicles, and the release probability at the docking site. We demonstrate that at Caenorhabditis elegans neuromuscular junctions two different classes of voltage-gated calcium channels, CaV2 and CaV1, mediate the release of distinct pools of synaptic vesicles. CaV2 channels are concentrated in densely packed clusters ~250 nm in diameter with the active zone proteins Neurexin, α-Liprin, SYDE, ELKS/CAST, RIM-BP, α-Catulin, and MAGI1. CaV2 channels are colocalized with the priming protein UNC-13L and mediate the fusion of vesicles docked within 33 nm of the dense projection. CaV2 activity is amplified by ryanodine receptor release of calcium from internal stores, triggering fusion up to 165 nm from the dense projection. By contrast, CaV1 channels are dispersed in the synaptic varicosity, and are colocalized with UNC-13S. CaV1 and ryanodine receptors are separated by just 40 nm, and vesicle fusion mediated by CaV1 is completely dependent on the ryanodine receptor. Distinct synaptic vesicle pools, released by different calcium channels, could be used to tune the speed, voltage-dependence, and quantal content of neurotransmitter release.

    1. Cell Biology
    2. Neuroscience
    Yu Wang, Meghan Lee Arnold ... Barth D Grant
    Research Article Updated

    Caenorhabditis elegans neurons under stress can produce giant vesicles, several microns in diameter, called exophers. Current models suggest that exophers are neuroprotective, providing a mechanism for stressed neurons to eject toxic protein aggregates and organelles. However, little is known of the fate of the exopher once it leaves the neuron. We found that exophers produced by mechanosensory neurons in C. elegans are engulfed by surrounding hypodermal skin cells and are then broken up into numerous smaller vesicles that acquire hypodermal phagosome maturation markers, with vesicular contents gradually degraded by hypodermal lysosomes. Consistent with the hypodermis acting as an exopher phagocyte, we found that exopher removal requires hypodermal actin and Arp2/3, and the hypodermal plasma membrane adjacent to newly formed exophers accumulates dynamic F-actin during budding. Efficient fission of engulfed exopher-phagosomes to produce smaller vesicles and degrade their contents requires phagosome maturation factors SAND-1/Mon1, GTPase RAB-35, the CNT-1 ARF-GAP, and microtubule motor-associated GTPase ARL-8, suggesting a close coupling of phagosome fission and phagosome maturation. Lysosome activity was required to degrade exopher contents in the hypodermis but not for exopher-phagosome resolution into smaller vesicles. Importantly, we found that GTPase ARF-6 and effector SEC-10/exocyst activity in the hypodermis, along with the CED-1 phagocytic receptor, is required for efficient production of exophers by the neuron. Our results indicate that the neuron requires specific interaction with the phagocyte for an efficient exopher response, a mechanistic feature potentially conserved with mammalian exophergenesis, and similar to neuronal pruning by phagocytic glia that influences neurodegenerative disease.