In SOD1G93A transgenic ALS mice, these MNs display early transcriptional alterations and endoplasmic reticulum (ER) stress (Saxena et al., 2009) and selectively express matrix metalloproteinase-9 (MMP-9), which regulates FαMN survival and disease progression (Kaplan et al., 2014). Here, MMP9 is linked to amyotrophic lateral sclerosis.