Comprehensive characterization of skeletal muscle remodeling in hSOD1G93A mice reveals limited functional impact of systemic FOXO1 inhibition

Authors
Ainhoa Vidal-Gil, Ignacio Azcue, Maria Levchuk, Amaia Elicegui, Oihane Pikatza-Menoio, Maddalen Robles-Cantero, Ane Otegui, María Rodríguez-Hidalgo, Laura Moreno-Martínez, Cristina Ruiz-Roldan, Andrea Valls, Bahaa Daou, Mikel García-Puga, Itziar Vergara, Ander Matheu, Amets Saenz, Rosario Osta, Adolfo López de Munain, Sonia Alonso-Martín


Lab

Journal
bioRxiv

Abstract

ABSTRACT

Background

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive motor neuron (MN) loss, muscle atrophy and paralysis. Although traditionally considered a MN-specific disease, accumulating evidence supports a crucial contribution of skeletal muscle pathology to disease onset and progression. Except for specific mutations, to date there is no effective treatment for ALS. FOXO transcription factors regulate programs of atrophy, metabolism and stress response in skeletal muscle, and their inhibition has shown beneficial effects in cellular and Drosophila models of ALS.

Methods

In this study, we investigated whether pharmacological FOXO inhibition (iFOXO) could modify disease progression and muscle pathology in female hSOD1G93A mice. Mice received daily oral administration of iFOXO starting at presymptomatic (P50; n=5 per group) or symptomatic (P90; n=9 mice per group) stages until end-stage. Body weight was monitored longitudinally, and motor performance was evaluated using grip strength and hanging-wire tests. Tibialis anterior and soleus muscles, representing fast- and slow-twitch muscles respectively, were analyzed by histology and immunofluorescence to assess fiber atrophy, fibrosis, lipid accumulation, satellite cell pool and fiber type composition. Quadriceps muscles (n=3 per group) were used for RNA-seq analysis.

Results

While histological analyses revealed severe fiber atrophy and increased fibrosis in hSOD1G93A mice, satellite cell numbers were preserved or mildly increased in a muscle and treatment onset dependent manner. iFOXO treatment did not improve motor performance, survival or attenuate muscle atrophy. Transcriptomic profiling indicated that genotype was the predominant driver of gene expression changes, while iFOXO produced only subtle, treatment onset dependent effects on pathways related to oxidative stress responses, mitochondrial function and adaptive metabolism.

Conclusion

Overall, FOXO inhibition alone showed limited therapeutic benefit in the hSOD1G93A ALS mouse model. These findings highlight the dominant influence of ALS driven molecular alterations over pharmacological modulation and emphasize the need for combinatorial therapeutic strategies targeting multiple disease mechanisms, including those preserving nerve health.

Keywords/Topics
skeletal muscle remodeling; hsod1g93a mice; cellular and drosophila models; female hsod1 g93a mice; mice; daily oral administration; grip strength; hanging-wire tests; molecular alterations; combinatorial therapeutic strategies

Source :

https://www.biorxiv.org/content/10.64898/2026.05.27.726208.abstract

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