Disruption of skeletal muscle mitochondrial network genes and miRNAs in amyotrophic lateral sclerosis

► ALS patients had a reduction in skeletal muscle PGC-1α mRNA and protein as well as ERRα and Mfn2 mRNA. ► ALS patients had reduced skeletal muscle citrate synthase and cytochrome c oxidase activities. ► ALS patients had an increase in skeletal muscle miR-23a, -29b, -206 and ‐455. ► Reporter assays confirmed that miR-23a repressed PGC-1α translation in a 3′ UTR dependent manner. ► Transgenic mice over expressing miR-23a had reduced PGC-1α, cytochome-b and COXIV protein levels.