SOD1 and amyotrophic lateral sclerosis: Interestingly, skeletal muscles of hFUS mice display a strong increase in S100A4 expression, accompanied by augmented levels of α-SMA, PDGFRβ, and STAT3, all proteins that have been widely demonstrated to be involved in muscle fibrosis and atrophy in both mutant SOD1 mouse models and in ALS patients [17, 32].