Amyotrophic lateral sclerosis (ALS) is a fetal neurodegenerative disease. The mechanism of sporadic ALS onset remains unclarified in detail. Disruption of zinc homeostasis could be related to sporadic ALS. Previously, we first reported miR-5572 as a microRNA (miRNA) among those identified in the spinal cords of patients with sporadic ALS. However, since its function in ALS remained unknown, this study further examined the role of miR-5572 in low-zinc status and ALS model cells which transfected with causative gene, Cu/Zn superoxide dismutase 1 (SOD1) G85R mutant vector. The miR-5572 level was increased by low-zinc condition accompanied by increase of endoplasmic reticulum (ER) stress. In addition, increase of miR-5572 enhanced the cellular toxicity induced by low-zinc treatment. The expression of miR-5572 was also increased, which was accompanied by an increase of ER stress markers associated with SOD1 aggregation formation. Cell death and ER stress makers levels induced by tunicamycin treatment were further increased in miR-5572 mimic-transfected cells. This study showed that miR-5572 exacerbated ER stress toxicity associated with low-zinc status and mutant SOD1 aggregates in ALS.
Keywords: amyotrophic lateral sclerosis; endoplasmic reticulum stress; miR-5572; microRNA; superoxide dismutase 1; zinc.