ALS Breakthrough: Unlocking Protein Production in Motor Neurons
Scientists at VIB and KU Leuven have made a groundbreaking discovery in the field of amyotrophic lateral sclerosis (ALS) research. They have identified a crucial molecular process that enables motor neurons to maintain protein production, a function that is disrupted in ALS. This finding, published in Nature Neuroscience, sheds light on an early weakness in neurodegeneration and opens up new possibilities for future therapies.
The Mystery of Protein Synthesis
Motor neurons rely on the ability to produce proteins locally within their axons to establish long-distance connections with muscles. To uncover the secrets of this process, researchers at the VIB-KU Leuven Center for Brain & Disease Research employed advanced spatial transcriptomics techniques. They analyzed gene expression in both neuron cell bodies and axons of adult mice, revealing a surprising discovery.
The axons of these neurons were found to contain high levels of the molecular machinery required for protein synthesis. This finding suggests that axons play a more active role in protein production than previously thought. However, in ALS models with disease-causing mutations in the RNA-binding protein FUS, this local protein production system was severely compromised.
The Key to Protein Synthesis: Eif5a
The researchers traced the issue to Eif5a, a protein essential for translation that requires a chemical modification called hypusination to function properly. In mutant neurons, the active form of Eif5a was notably absent from the axons, leading to reduced local protein synthesis. This discovery highlights the critical role of Eif5a in maintaining protein production in motor neurons.
A Natural Solution: Spermidine
Dr. Diana Piol, the first author of the study, explained that local translation depends on the protein levels of Dohh, an enzyme crucial for Eif5a hypusination. By supplying axons with spermidine, a naturally occurring molecule necessary for this modification, researchers were able to restore Eif5a activity. This, in turn, improved local protein production, strengthened axonal structure, and enhanced neuronal activity.
Early Intervention, Potential Therapeutic Impact
Prof. Sandrine Da Cruz, the senior author, emphasized that these defects in protein production begin in axons, long before the neurons themselves degenerate. By restoring protein synthesis in axons, the research team successfully reduced disease-related damage in various ALS models. This discovery was made possible by the innovative use of spatial transcriptomics, which allowed them to map gene expression within neuronal subcellular compartments, emphasizing the importance of distal axon homeostasis as a promising therapeutic target.
The study's findings also extended to fruit fly models of ALS linked to both FUS and TDP-43, suggesting that this pathway may hold relevance across different forms of the disease. While these findings do not directly lead to a treatment, they identify Eif5a hypusination as a promising therapeutic target and demonstrate the power of spatial analysis in uncovering early, compartment-specific mechanisms in neurodegenerative diseases.
Funding and Acknowledgments
This research was supported by various organizations, including the FWO, the Muscular Dystrophy Association, the Alzheimer Research Foundation, VIB-Tech Watch, KU Leuven Opening the Future, ALS Canada, and Brain Canada. The authors express gratitude for the contributions of these funding bodies, which made this groundbreaking study possible.
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Journal Reference:
Piol, D., et al. (2025). Axonal Eif5a hypusination controls local translation and mitigates defects in FUS-ALS. Nature Neuroscience. doi: 10.1038/s41593-025-02101-2. https://www.nature.com/articles/s41593-025-02101-2
