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Mn and Cu/Zn SOD expression in cells from LPS-sensitive and LPS-resistant mice
L S Gibbs1, P J Del Vecchio, J B Shaffer
1Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509.
Abstract:
We examined the effect of lipopolysaccharide (LPS) treatment on the expression of manganese and copper/zinc superoxide dismutase (MnSOD and Cu/ZnSOD) mRNA and protein in resident peritoneal macrophages and lung endothelial cells derived from LPS-sensitive (LPS-s) and LPS-resistant (LPS-r) mice. Macrophages from both LPS-s and LPS-r mice treated with LPS for 24 h produced increased levels of MnSOD mRNA and protein. In contrast, levels of lung endothelial cell MnSOD mRNA and protein from LPS-s mice were increased by LPS treatment, while no increases in these parameters were observed in endothelial cells from LPS-r mice. Tumor necrosis factor-alpha (TNF alpha) treatment, however, did increase levels of MnSOD mRNA in both LPS-s and LPS-r endothelial cells to an equal extent. Both macrophage and endothelial cell Cu/ZnSOD mRNA and protein levels were not significantly affected by LPS treatment. These results demonstrate that the mutation that affects susceptibility to LPS in LPS-r mice exerts a differential influence on MnSOD inducibility in a cell specific manner.
Insights
Lipopolysaccharide (LPS) affects manganese superoxide dismutase (MnSOD) differently in macrophages and lung cells of resistant mice. This indicates a cell-specific genetic influence on MnSOD expression.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Lipopolysaccharide (LPS) is a key component of Gram-negative bacteria, triggering immune responses.
- Superoxide dismutase (SOD) enzymes, including MnSOD and Cu/ZnSOD, are crucial for cellular defense against oxidative stress.
- Genetic variations can influence an organism's response to LPS, impacting immune cell function and oxidative stress pathways.
Purpose of the Study:
- To investigate the impact of LPS on MnSOD and Cu/ZnSOD mRNA and protein expression.
- To compare these effects in macrophages and lung endothelial cells from LPS-sensitive (LPS-s) and LPS-resistant (LPS-r) mice.
- To elucidate the cell-specific and mutation-dependent regulation of MnSOD in response to LPS.
Main Methods:
- Primary cultures of resident peritoneal macrophages and lung endothelial cells were isolated from LPS-s and LPS-r mice.
- Cells were treated with LPS for 24 hours.
- Quantitative analysis of MnSOD and Cu/ZnSOD mRNA and protein expression was performed.
Main Results:
- LPS treatment significantly increased MnSOD mRNA and protein levels in macrophages from both LPS-s and LPS-r mice.
- In contrast, LPS increased MnSOD mRNA and protein in lung endothelial cells only from LPS-s mice; LPS-r endothelial cells showed no increase.
- Tumor necrosis factor-alpha (TNF-α) treatment upregulated MnSOD mRNA in endothelial cells from both mouse types equally, suggesting a different regulatory pathway.
- Cu/ZnSOD mRNA and protein levels were not significantly altered by LPS in either cell type or mouse strain.
Conclusions:
- The genetic mutation conferring LPS resistance in mice influences MnSOD inducibility in a cell-specific manner.
- Macrophages exhibit a consistent MnSOD response to LPS regardless of sensitivity, unlike lung endothelial cells.
- These findings highlight distinct cellular mechanisms governing MnSOD expression and oxidative stress responses in the context of LPS sensitivity.