NeuroCyto: the neuronal cytoskeleton in health and disease

Team leader: 
Description: 

The team started in 2017 as part of the CNRS ATIP program. At NeuroCyto, we are neuronal cell biologists: we want to understand how neurons are organized at the cellular level. How do they differentiate, then build and maintain their complex arborization? How do they establish and conserve their polarity, with the axon and dendrites allowing to send and receive signals? Numerous processes contribute to this organization: elaboration of the cell architecture (thanks to the cytoskeleton), protein transport inside the cell (with diffusion and motor proteins), segregation into distinct compartments (such as axon, synapses, dendritic spines…). We apply advanced microscopy techniques to directly observe molecular assemblies at the nanoscale in neurons, revealing how they organize the neuron and shape its physiology.

The NeuroCyto team members

Research topics: 

We are currently focusing on actin organization within axons. Several new axonal actin structures have been discovered by us and others, including submembrane actin rings and intra-axonal actin hotspots and trails. We want to understand the functions of these structures and their relevance for physiological processes such as axonal transport and proper functioning of presynaptic boutons. To do so, we take advantage of the beautiful model of hippocampal neurons in low-density culture, so we can visualize the intricate morphology of individual neurons and follow individual axons. We combine live-cell imaging, targeted manipulations and super-resolution microscopy to connect the dynamic behavior of axonal components to the nanoscale organization of the cytoskeleton, and we devote substantial efforts to implement innovative strategies for the labeling, observation and analysis of these processes. We explore the pathophysiological relevance of our finding by studying cellular models of Alzheimer’s disease, as axonal transport and presynapstic function are compromised in the early stages of the disease.

Role of actin-based nanostructures in axons 

Following the identification of new axonal actin structures (rings, hotspots and trails), we want to understand their molecular architecture, assembly mechanism and potential interplay. This is done thanks to a combination of live-cell imaging and super-resolution microscopy techniques as well as innovative stragegies to selectively perturb actin within axons. 

Collaboration with the lab of Subhojit Roy, University of Wisconsin, Madison, USA.

New approaches for labeling, imaging and analysis in super-resolution microscopy

To reveal the organization of the axon, a intricate cellular compartment with extensive length and branching, we use optical super-resolution microscopy. We are specialists of Single Molecule Localization Microscopy (SMLM), and we keep working to push the methods, implementing and testing new techniques as soon as they appear. This includes labeling methods for highly-multiplexed acquisition such as DNA-PAINT, automated acquisition strategies, and new image analysis algorithms.

Collaboration with the lab of Ricardo Henriques, UCL/Crick Institute, London, UK and the Abbelight company (Paris, France)

Cell biology of Alzheimer’s disease in relevant cellular models

Impairment of axonal transport and presynaptic release are early-stage events in Alzheimer’s disease. Using our cell biology background, we want to gain a better understanding of why this happens by studying the nanoscale organization of the axon in Alzheimer’s disease models. Starting with classical rodent models, we want to turn to human models thanks to neurons obtained from induced pluripotent stem cells developed by the Nivet team. These models are still poorly characterized at the subcellular organization level, and it will be interesting to look for specific defects in neurons derived from Alzheimer’s disease patients.

Collaboration with the Nivet team at INP.

Partners: 

    

Gallery

    • Cover for Leterrier J Neurosci 2018

      Cover for Leterrier J Neurosci 2018 (see publications list below).

    • Cover for Huang et al. J Neurosci 2017

      Cover for Huang et al. J Neurosci 2017 (see publications list below).

    • Cover for Ganguly et al. JCB 2015

      Cover for Ganguly et al. JCB 2015 (see publications list below).

    • 3D-STORM image of an axonal growth cone labeled for actin (depth color-code)

      3D-STORM image of an axonal growth cone labeled for actin (depth color-code)

    • Hippocampal neurons in culture labeled for microtubules (grey) and ß4-spectrin (magenta).

      Hippocampal neurons in culture labeled for microtubules (grey) and ß4-spectrin (magenta).

    • Hippocampal neuron labeled for actin (green), microtubules (blue) and neurofascin (red).

      Hippocampal neuron labeled for actin (green), microtubules (blue) and neurofascin (red).

    • Color-coded time lapse of an hippocampal neuron in culture expressing a fluorescent membrane-targeted protein, showing waves along the neurites (rainbow colors).

      Color-coded time lapse of an hippocampal neuron in culture expressing a fluorescent membrane-targeted protein, showing waves along the neurites (rainbow colors).

    • COS cell labeled for actin (grey), microtubules (red), clathrin (green) and DNA (DAPI).

      COS cell labeled for actin (grey), microtubules (red), clathrin (green) and DNA (DAPI).

    • Hippocampal neuron labeled for actin (STORM image, orange) and synapsin (TIRF image, blue).

      Hippocampal neuron labeled for actin (STORM image, orange) and synapsin (TIRF image, blue).

Team publications