Dynamic neuromuscular remodeling precedes motor-unit loss in a mouse model of ALS
- Université de Montréal, Canada
Abstract
Despite being an early event in ALS, it remains unclear whether the denervation of neuromuscular junctions (NMJ) is simply the first manifestation of a globally degenerating motor neuron. Using in vivo imaging of single axons and their NMJs over a three-month period, we identify that single motor-units are dismantled asynchronously in SOD1G37R mice. We reveal that weeks prior to complete axonal degeneration, the dismantling of axonal branches is accompanied by contemporaneous new axonal sprouting resulting in synapse formation onto nearby NMJs. Denervation events tend to propagate from the first lost NMJ, consistent with a contribution of neuromuscular factors extrinsic to motor neurons, with distal branches being more susceptible. These results show that NMJ denervation in ALS is a complex and dynamic process of continuous denervation and new innervation rather than a manifestation of sudden global motor neuron degeneration.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data has been provided for Figure 1, Figure 2 - Supplement 1, Figure 4, Figure 4 - Supplement 1, and Figure 5.
Article and author information
Author details
Richard Robitaille
Funding
Canadian Institutes of Health Research (MOP-111070)
- Richard Robitaille
Canadian Foundation for Innovation
- Christine Vande Velde
- Richard Robitaille
ALS Society of Canada (Doctoral Research Award)
- Éric Martineau
Muscular Dystrophy Association
- Christine Vande Velde
Fonds de Recherche du Québec - Santé
- Christine Vande Velde
Robert Packard Center for ALS research
- Richard Robitaille
Canadian Institutes of Health Research (PJT-152934)
- Adriana Di Polo
ALS Society of Canada
- Christine Vande Velde
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 experiments were performed in accordance with the guidelines of the Canadian Council on Animal Care, the Comité de Déontologie sur l'Expérimentation Animale of Université de Montréal (protocol #18-040) and the CRCHUM Institutional Committee for the Protection of Animals (protocol #N16008CVV and #N15047ADPs).
Copyright
© 2018, Martineau 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
-
- 3,852
- views
-
- 679
- downloads
-
- 95
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
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)
Dynamic neuromuscular remodeling precedes motor-unit loss in a mouse model of ALS
eLife 7:e41973.
https://doi.org/10.7554/eLife.41973
