Skeletal-Muscle Metabolic Reprogramming in ALS-SOD1 <sup>G93G</sup> Mice Predates Disease Onset and is a Promising Therapeutic Target

Abstract

Besides loss of motor neurons in spinal cord, brainstem and cerebral cortex, patients with ALS show an abnormal depletion of energy stores and a parallel hypermetabolism in spite of simultaneous progression of skeletal muscle atrophy. Our results highlighted bioenergetic defects in skeletal muscle of ALS mice long before the disease onset that lead to deep modifications of muscle physiology. Muscle remodelling occurs in SOD1G93A mice before the activation of muscle denervation markers and this is followed by an increase of energy expenditure unrelated to physical activity. To this regard our attention has been focused on the identification of precocious biomarkers closely related to hypermetabolism, a phenomenon that possesses prognostic and diagnostic relevance. Finally, chronic Ranolazine treatment, a FDA-approved inhibitor of fatty acid b-oxidation, decreases energy expenditure in symptomatic SOD1G93A mice and this correlates with a robust, albeit temporary, recovery of pathological phenotype.