scholarly journals Manganese superoxide dismutase and inducible nitric oxide synthase modify early oxidative events in acute Adriamycin-induced mitochondrial toxicity

2005 ◽  
Vol 4 (7) ◽  
pp. 1056-1064 ◽  
Author(s):  
Luksana Chaiswing ◽  
Marsha P. Cole ◽  
Wanida Ittarat ◽  
Luke I. Szweda ◽  
Daret K. St. Clair ◽  
...  
1997 ◽  
Vol 273 (5) ◽  
pp. L1002-L1006 ◽  
Author(s):  
Todd C. Brady ◽  
Ling-Yi Chang ◽  
Brian J. Day ◽  
James D. Crapo

Inflammatory cytokines have been shown to upregulate secretion of the antioxidant enzyme extracellular superoxide dismutase (EC-SOD) in dermal fibroblasts and, in other cells, to stimulate production of nitric oxide (⋅ NO). Because superoxide rapidly scavenges ⋅ NO, forming the injurious peroxynitrite anion (OONO−), we hypothesize that stimulated cells upregulate EC-SOD expression concurrently with ⋅ NO release. To test for coregulation of EC-SOD and ⋅ NO within the same cell, the timing of inducible nitric oxide synthase (iNOS) and EC-SOD transcription was measured after exposure of a rat type II pneumocyte analog, the L2 cell line, to a combination of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). Upregulation of iNOS and EC-SOD transcription occurred after 6 h of exposure, and transcription of both genes was linked by activation of the transcription factor nuclear factor-κB. Both EC-SOD and iNOS were elevated in rat lung homogenates 24 h after intratracheal instillation with IFN-γ and TNF-α. The observation that EC-SOD and iNOS are temporally coregulated after cytokine exposure suggests the possibility of a critical mechanism by which cells might protect ⋅ NO and avoid the formation of OONO−during inflammation.


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