CHI3L1 and amyotrophic lateral sclerosis: In line with our results, a previous study focused on up-regulated genes in astrocytes expressing mutated TAR DNA binding protein 43 (TDP-43), a causative factor in amyotrophic lateral sclerosis, also showed decreased cell viability in cortical neurons treated at 10 DIV with CHI3L1 for 4 days, although at higher doses (500–1000 ng/ml)7.