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Essential role of NF-kappa B activation in silica-induced inflammatory mediator production in macrophages
1Department of Pathology, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033, USA.
Abstract:
In this report, we demonstrate that NF-kappa B, a ubiquitous transcription factor, plays an essential role in silica-induced inflammatory mediator production in the mouse macrophage cell line RAW 264.7. Compared to the effect of lipopolysaccharide (LPS), silica mediated a stronger activation of NF-kappa B p50/p50 homodimer at early phase of poststimulation. Furthermore, activation of NF-kappa B by silica and LPS appears to be mediated by different signal transduction pathways. Both silica and LPS increased mRNA expression in these cells for cyclooxygenase II, inducible nitric oxide synthase, tumor necrosis factor-alpha and interleukin-1 alpha. This expression was attenuated along with the inhibition of NF-kappa B activation.
Insights
Nuclear Factor kappa B (NF-kappa B) is crucial for silica-induced inflammatory mediator production in mouse macrophages. Silica strongly activates NF-kappa B, influencing inflammatory gene expression differently than lipopolysaccharide (LPS).
Area of Science:
- Immunology
- Molecular Biology
- Toxicology
Background:
- Nuclear Factor kappa B (NF-kappa B) is a key transcription factor involved in immune responses.
- Silica exposure can trigger inflammatory processes in macrophages.
- Understanding the molecular mechanisms of silica-induced inflammation is important for public health.
Purpose of the Study:
- To investigate the role of NF-kappa B in silica-induced inflammatory mediator production.
- To compare the effects of silica and lipopolysaccharide (LPS) on NF-kappa B activation.
- To elucidate the signaling pathways involved in silica-mediated inflammation.
Main Methods:
- Utilized the mouse macrophage cell line RAW 264.7.
- Stimulated cells with silica and lipopolysaccharide (LPS).
- Assessed NF-kappa B activation (p50/p50 homodimer) and mRNA expression of inflammatory mediators.
Main Results:
- Silica induced a stronger early activation of NF-kappa B p50/p50 homodimer compared to LPS.
- Silica and LPS appear to activate NF-kappa B via distinct signal transduction pathways.
- Both silica and LPS increased mRNA expression of cyclooxygenase II, inducible nitric oxide synthase, tumor necrosis factor-alpha, and interleukin-1 alpha.
- Inhibition of NF-kappa B activation attenuated the mRNA expression of these inflammatory mediators.
Conclusions:
- NF-kappa B plays an essential role in silica-induced inflammatory mediator production.
- Silica and LPS differentially regulate NF-kappa B activation and inflammatory gene expression.
- Targeting NF-kappa B signaling may offer therapeutic strategies for silica-induced inflammation.