Role of PI3K and GSK-3 activity in pathogenic mechanism of motoneuron cell death induced by the G93A or A4V mutant hSOD1 gene, in vitro model of familial ALS

Abstract

G93A or A4V mutations in the human Cu/Zn-superoxide dismutase gene (hSOD1) cause familial amyotrophic lateral sclerosis (fALS). However, it has not yet been clearly understood how those bring about fALS. Method : To investigate effects of the G93A or A4V mutations on phosphatydilinositol-3-kinase (PI3K)/Akt and glycogen synthase kinase-3 (GSK-3) as another pathogenic mechanism, VSC4.1 motoneurons transfected with G93A- or A4V-mutant hSOD1 (G93A and A4V cells, respectively) were compared with them transfected with wild type (wild cells) in cell viability and intracellular signals, including PI3K/Akt, GSK-3, cytochrome c, caspase-3 and poly(ADP-ribose) polymerase (PARP). And, to evaluate whether decreased PI3K and increased GSK-3 play an important role in death of G93A and A4V cells, those cells were treated with GSK-3 inhibitor or PI3K enhancer, and then MTT assay and Western blotting were done