ABCB1 and amyotrophic lateral sclerosis: The mechanism of P-glycoprotein (P-gp) upregulation observed in the spinal cord of ALS patients and SOD1 mutated animal models has been studied, using human iPS-derived endothelial cells and astrocytes from different causal factors (sporadic, SOD1-AV4 and C9orf72) [38].