MAB4081 Sigma-AldrichAnti-MnSOD Antibody, clone MnS-1

Oxidative stress damages cells. NaCl and urea are high in renal medullary interstitial fluid, which is necessary to concentrate urine, but which causes oxidative stress by elevating reactive oxygen species (ROS). Here, we measured the antioxidant enzyme superoxide dismutases (SODs, MnSOD, and Cu/ZnSOD) and catalase in mouse kidney that might mitigate the oxidative stress. MnSOD protein increases progressively from the cortex to the inner medulla, following the gradient of increasing NaCl and urea. MnSOD activity increases proportionately, but MnSOD mRNA does not. Water restriction, which elevates renal medullary NaCl and urea, increases MnSOD protein, accompanied by a proportionate increase in MnSOD enzymatic activity in the inner medulla, but not in the cortex or the outer medulla. In contrast, Cu/ZnSOD and TNF-α (an important regulator of MnSOD) do not vary between the regions of the kidney, and expression of catalase protein actually decreases from the cortex to the inner medulla. Water restriction increases activity of mitochondrial enzymes that catalyze production of ROS in the inner medulla, but reduces NADPH oxidase activity there. We also examined the effect of high NaCl and urea on MnSOD in Madin-Darby canine kidney (MDCK) cells. High NaCl and high urea both increase MnSOD in MDCK cells. This increase in MnSOD protein apparently depends on the elevation of ROS since it is eliminated by the antioxidant N-acetylcysteine, and it occurs without raising osmolality when ROS are elevated by antimycin A or xanthine oxidase plus xanthine. We conclude that ROS, induced by high NaCl and urea, increase MnSOD activity in the renal inner medulla, which moderates oxidative stress.

Recent studies in an experimental model of rabies showed major structural changes in the brain involving neuronal processes that are associated with severe clinical disease. Cultured adult rat dorsal root ganglion (DRG) neurons infected with the challenge virus standard-11 strain of rabies virus (CVS) showed axonal swellings and immunostaining for 4-hydroxy-2-nonenal (4-HNE), indicating evidence of lipid peroxidation associated with oxidative stress and reduced axonal growth compared to that of mock-infected DRG neurons. We have evaluated whether nuclear factor (NF)-κB might act as a critical bridge linking CVS infection and oxidative stress. On Western immunoblotting, CVS infection induced expression of the NF-κB p50 subunit compared to that of mock infection. Ciliary neurotrophic factor, a potent activator of NF-κB, had no effect on mock-infected rat DRG neurons and reduced the number of 4-HNE-labeled puncta. SN50, a peptide inhibitor of NF-κB, and CVS infection had an additive effect in producing axonal swellings, indicating that NF-κB is neuroprotective. The fluorescent signal for subunit p50 was quantitatively evaluated in the nucleus and cytoplasm of mock- and CVS-infected rat DRG neurons. At 24 h postinfection (p.i.), there was a significant increase in the nucleus/cytoplasm ratio, indicating increased transcriptional activity of NF-κB, perhaps as a response to stress. At both 48 and 72 h p.i., there was significantly reduced nuclear localization of NF-κB. CVS infection may induce oxidative stress by inhibiting nuclear activation of NF-κB. A rabies virus protein may directly inhibit NF-κB activity. Further investigations are needed to gain a better understanding of the basic mechanisms involved in the oxidative damage associated with rabies virus infection.

To identify temporal changes in protein expression in the irradiated rat lung and generate putative mechanisms underlying the radioprotective effect of the manganese superoxide dismutase mimetic MnTE-2-PyP(5+).Female Fischer 344 rats were irradiated to the right hemithorax with a single dose of 28 Gy and killed from day 1 to 20 weeks after irradiation. Proteomic profiling was performed to identify proteins that underwent significant changes in abundance. Some irradiated rats were administered MnTE-2-PyP(5+) and changes in protein expression and phosphorylation determined at 6 weeks after irradiation.Radiation induced a biphasic stress response in the lung, as shown by the induction of heme oxygenase 1 at 1-3 days and at 6-8 weeks after irradiation. At 6-8 weeks after irradiation, the down-regulation of proteins involved in cytoskeletal architecture (filamin A and talin), antioxidant defense (biliverdin reductase and peroxiredoxin II), and cell signaling (β-catenin, annexin II, and Rho-guanosine diphosphate dissociation inhibitor) was observed. Treatment with MnTE-2-PyP(5+) partially prevented the apparent degradation of filamin and talin, reduced the level of cleaved caspases 3 and 9, and promoted Akt phosphorylation as well as β-catenin expression.A significant down-regulation of proteins and an increase in protein markers of apoptosis were observed at the onset of lung injury in the irradiated rat lung. Treatment with MnTE-2-PyP(5+), which has been demonstrated to reduce lung injury from radiation, reduced apparent protein degradation and apoptosis indicators, suggesting that preservation of lung structural integrity and prevention of cell loss may underlie the radioprotective effect of this compound.