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Here, Prakasam and colleagues show that polyQ-expanded androgen receptor toxicity can be attenuated using artificial miRNAs targeting Lsd1 and Prmt6, two AR-co-activators overexpressed in an androgen-dependent manner specifically in skeletal muscle, thus ameliorating spinal-bulbar muscular atrophy phenotypes in flies and mice.

Marchioretti and colleagues show that in the skeletal muscle of SBMA mice and patients there is an early, but reversible alteration of expression of genes involved in muscle contraction and of mitochondrial respiration, followed by accumulation of calcium inside the mitochondria, which is concomitant with the onset of motor dysfunction, and late alteration of muscle structure.

Amyotrophic lateral sclerosis (ALS) is a motor neuron (MN) disease associated with progressive muscle atrophy, paralysis, and eventually death. Growing evidence demonstrates that the pathological process leading to ALS is the result of multiple altered mechanisms occurring not only in MNs but also in other cell types inside and outside the central nervous system. In this context, the involvement of skeletal muscle has been the subject of a few studies on patients and ALS animal models. In this work, by using primary myocytes derived from the ALS transgenic hSOD1(G93A) mouse model, we observed that the myogenic capability of such cells was defective compared to cells derived from control mice expressing the nonpathogenic hSOD1(WT) isoform. The correct in vitro myogenesis of hSOD1(G93A) primary skeletal muscle cells was rescued by the addition of a conditioned medium from healthy hSOD1(WT) myocytes, suggesting the existence of an in trans activity of secreted factors. To define a dataset of molecules participating in such safeguard action, we conducted comparative metabolomic profiling of a culture medium collected from hSOD1(G93A) and hSOD1(WT) primary myocytes and report here an altered secretion of amino acids and lipid-based signaling molecules. These findings support the urgency of better understanding the role of the skeletal muscle secretome in the regulation of the myogenic program and mechanisms of ALS pathogenesis and progression.