Inactivation of cytochrome c oxidase by mutant SOD1s in mouse motoneuronal NSC-34 cells is independent from copper availability but is because of nitric oxide
Article first published online: 20 OCT 2009
© 2009 The Authors. Journal Compilation © 2009 International Society for Neurochemistry
Journal of Neurochemistry
Volume 112, Issue 1, pages 183–192, January 2010
How to Cite
Arciello, M., Capo, C. R., Cozzolino, M., Ferri, A., Nencini, M., Carrì, M. T. and Rossi, L. (2010), Inactivation of cytochrome c oxidase by mutant SOD1s in mouse motoneuronal NSC-34 cells is independent from copper availability but is because of nitric oxide. Journal of Neurochemistry, 112: 183–192. doi: 10.1111/j.1471-4159.2009.06441.x
- Issue published online: 8 DEC 2009
- Article first published online: 20 OCT 2009
- Received June 24, 2009; revised manuscript received October 9, 2009; accepted October 12, 2009
- copper, zinc superoxide dismutase;
- cytochrome c oxidase;
- familial amyotrophic lateral sclerosis;
- nitric oxide
J. Neurochem. (2010) 112, 183–192.
The copper-enzyme cytochrome c oxidase (Cytox) has been indicated as a primary molecular target of mutant copper, zinc superoxide dismutase (SOD1) in familial amyotrophic lateral sclerosis (fALS); however, the mechanism underlying its inactivation is still unclear. As the toxicity of mutant SOD1s could arise from their selective recruitment to mitochondria, it is conceivable that they might compete with Cytox for the mitochondrial copper pool causing Cytox inactivation. To investigate this issue, we used mouse motoneuronal neuroblastoma × spinal cord cell line-34, stably transfected for the inducible expression of low amounts of wild-type or mutant (G93A, H46R, and H80R) human SOD1s and compared the effects observed on Cytox with those obtained by copper depletion. We demonstrated that all mutants analyzed induced cell death and decreased the Cytox activity, but not the protein content of the Cytox subunit II, at difference with copper depletion that also affected subunit II protein. Copper supplementation did not counteract mutant hSOD1s toxicity. Otherwise, the treatment of neuroblastoma × spinal cord cell line-34 expressing G93A, H46R, or H80R hSOD1 mutants, and showing constitutive expression of iNOS and nNOS, with either a NO scavenger, or NOS inhibitors prevented the inhibition of Cytox activity and rescued cell viability. These results support the involvement of NO in mutant SOD1s-induced Cytox damage, and mitochondrial toxicity.