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Impairment of the mitochondrial electron chain transport prevents NF-kappa B activation by hydrogen peroxide
C Josse1, S Legrand-Poels, B Piret
1Laboratory of Fundamental Virology, University of Liège, Belgium.
Abstract:
A large body of work has been devoted to mechanisms leading to the activation of the transcription factor NF-kappa B in various cell types. Several studies have indicated that NF-kappa B activation by numerous stimuli depends on the intracellular generation of reactive oxygen species (ROS). In this report, we first demonstrated that inhibition of the electron transport chain by either rotenone or antimycine A gave rise to dose-dependent inhibition of NF-kappa B translocation induced by 150 microM of hydrogen peroxide (H2O2). Conversely, the impairment of the mitochondrial respiratory chain did not affect T lymphocyte treatment by TNF-alpha (tumor necrosis factor alpha) or pre-B lymphocyte treatment with LPS (lipopolysaccharide). We also showed that oligomycine which inhibits ATP synthase and FCCP, which uncouples respiration also led to dose-dependent inhibition of NF-kappa B activation by H2O2. All these inhibitors were also shown to inhibit mitochondrial respiration in lymphocytes assessed by oxygen consumption. Although only a transient drop in ATP concentration was observed when lymphocytes were treated by H2O2, this effect was remarkably reinforced in the presence of oligomycine demonstrating the crucial role of ATP in the signal transduction pathway induced by H2O2.
Insights
Mitochondrial electron transport chain inhibition blocks NF-kappa B activation by hydrogen peroxide (H2O2) in lymphocytes. This suggests reactive oxygen species (ROS) generated by mitochondria are crucial for this specific signaling pathway.
Area of Science:
- Cellular Biology
- Immunology
- Biochemistry
Background:
- Nuclear factor kappa B (NF-kappa B) activation is critical in cellular responses.
- Reactive oxygen species (ROS) are implicated in NF-kappa B signaling.
- The precise role of mitochondrial function in NF-kappa B activation requires further elucidation.
Purpose of the Study:
- To investigate the role of mitochondrial electron transport chain and ATP production in NF-kappa B activation.
- To determine if hydrogen peroxide (H2O2)-induced NF-kappa B activation is dependent on mitochondrial respiration.
Main Methods:
- Inhibition of mitochondrial electron transport chain using rotenone and antimycin A.
- Assessment of NF-kappa B translocation induced by H2O2, tumor necrosis factor alpha (TNF-alpha), and lipopolysaccharide (LPS).
- Measurement of cellular ATP levels and oxygen consumption in lymphocytes.
Main Results:
- Rotenone and antimycin A dose-dependently inhibited H2O2-induced NF-kappa B translocation.
- Mitochondrial inhibitors did not affect NF-kappa B activation by TNF-alpha or LPS.
- Oligomycin and FCCP also inhibited H2O2-induced NF-kappa B activation, correlating with reduced oxygen consumption.
- H2O2 caused a transient ATP drop, significantly enhanced by oligomycin, highlighting ATP's role.
Conclusions:
- Mitochondrial respiration is essential for H2O2-induced NF-kappa B activation in lymphocytes.
- ATP generated through mitochondrial respiration plays a key role in this specific signaling pathway.
- NF-kappa B activation by other stimuli like TNF-alpha and LPS is independent of mitochondrial respiration.