Impairment of glutamate transport and increased vulnerability to oxidative stress in neuroblastoma SH-SY5Y cells expressing a Cu,Zn superoxide dismutase typical of familial amyotrophic lateral sclerosis.
Human neuroblastoma SH-SY5Y cells transfected with either familial amyotrophic lateral sclerosis-typical G93A mutant or wild-type copper/zinc superoxide dismutase were compared to untransfected cells in term of glutamate transport. Vmax of glutamate uptake was reduced in mutant cells, with no change in Km. No difference in EAAT1, EAAT2 and EAAT3 glutamate transporter mRNAs and immunoreactive proteins was found, suggesting that one or more transporters are functionally inactivated, possibly due to increased oxidative stress induced by the G93A mutation. Mutant cells showed a marked sensitivity to oxidants, resulting in a more pronounced reduction of glutamate uptake. Short-term antioxidant treatment did not reverse the impairment of glutamate uptake in G93A cells. Interestlingly, N-acetylcysteine was partially effective in preventing glutamate uptake reduction due to exogenous oxidative insults. Since the inhibition of the EAAT2 transporter subtype had no effect on glutamate re-uptake in this model, our study suggests an impaired function of the EAAT1/3 transporter subtypes, possibly due to oxidative inactivation, in the presence of mutant copper/zinc superoxide dismutase. Therefore, this model might prove to be a valuable tool to study the effects of mutant copper/zinc superoxide dismutase associated with amyotrophic lateral sclerosis on glutamate transport in neuronal cells, without the specific contribution of glial cells. These findings might lead to the identification of new therapeutic strategies aimed at preventing the damage associated with ALS.
Sala
Gessica
G
Department of Neuroscience and Biomedical Technologies, University of Milano-Bicocca, via Cadore, 48-20052 Monza (MI), Italy.
Beretta
Simone
S
Ceresa
Chiara
C
Mattavelli
Laura
L
Zoia
Chiara
C
Tremolizzo
Lucio
L
Ferri
Alberto
A
Carrì
Maria Teresa
MT
Ferrarese
Carlo
C
D027322:Amino Acid Transport System X-AG / Q000378:metabolism; D000690:Amyotrophic Lateral Sclerosis / Q000201:enzymology*; D000975:Antioxidants / Q000494:pharmacology; D001693:Biological Transport, Active / Q000502:physiology; D001932:Brain Neoplasms / Q000201:enzymology* / Q000378:metabolism*; D045744:Cell Line, Tumor; D004587:Electrophoresis, Agar Gel; D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D009154:Mutation / Q000502:physiology; D009447:Neuroblastoma / Q000201:enzymology* / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012964:Sodium / Q000502:physiology; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism*; D027981:Symporters / Q000378:metabolism
D027322:Amino Acid Transport System X-AG; D000975:Antioxidants; D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D050491:Glutamate Plasma Membrane Transport Proteins; D016877:Oxidants; D012333:RNA, Messenger; C493400:SLC1A1 protein, human; C493397:SLC1A2 protein, human; C493394:SLC1A3 protein, human; D027981:Symporters; D018698:Glutamic Acid; D012964:Sodium; D013482:Superoxide Dismutase