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Updated: Apr 12, 2026
A Protocol for Detecting and Scavenging Gas-phase Free Radicals in Mainstream Cigarette Smoke
Published on: January 2, 2012
Molecular mechanisms of the impact of smoke-oxidants
Halina Milnerowicz1, Milena Ściskalska1, Magdalena Dul2
1Department of Biomedical and Environmental Analysis, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211, 50-556 Wroclaw, Poland.
Abstract:
Tobacco smoke is a source of many xenobiotics and free radicals. Reactive oxygen species can affect the body both directly and indirectly, through the activation of both signalling pathways and transcription factors (NF-κB and AP-1). One of the most important signalling cascades which can affect the oxidants in smoke are mitogen-activated protein kinases (MAPK). The mechanism of MAPK pathways activation by reactive oxygen species depends on the stimulation of specific tyrosine kinases and protein tyrosine phosphatases inactivation. An activated MAP protein can initiate AP-1 signalling and interact with many other transcription factors. The components of tobacco smoke with oxidation-reduction properties can have an effect on NF-κB signalling. Binding of NF-κB and AP-1 with DNA is a complicated process, in which coactivators exhibiting internal histone acetyltransferase activity are involved. The balance between histone deacetylases and acetylases is important for the regulation of inflammatory response in the lungs. Tobacco smoke causes increased acetylase activity and decreased deacetylase activity in epithelial lung cells. The result is an increase in the activation of NF-κB and AP-1. Oxygen free radicals from tobacco smoke can change the redox status of cells, which can in turn induce the activation of transcription factors, chromatin remodelling and intensified genes transcription for inflammatory mediators.
Insights
Tobacco smoke triggers reactive oxygen species, activating key signaling pathways like MAPK. This leads to increased transcription factors (NF-κB and AP-1), promoting inflammatory responses in lung epithelial cells.
Area of Science:
- Molecular Biology
- Cellular Signaling
- Toxicology
Background:
- Tobacco smoke contains numerous xenobiotics and free radicals.
- Reactive oxygen species (ROS) from smoke impact cellular processes directly and indirectly.
- ROS activate critical signaling pathways and transcription factors, including NF-κB and AP-1.
Purpose of the Study:
- To elucidate the mechanisms by which tobacco smoke oxidants activate mitogen-activated protein kinase (MAPK) pathways.
- To investigate the role of MAPK signaling in the activation of transcription factors NF-κB and AP-1.
- To understand how tobacco smoke affects the epigenetic regulation of inflammatory genes in lung cells.
Main Methods:
- Analysis of MAPK pathway activation by ROS, involving tyrosine kinases and phosphatases.
- Investigation of NF-κB and AP-1 DNA binding mechanisms, including coactivator involvement.
- Assessment of histone acetyltransferase and deacetylase activity in lung epithelial cells exposed to smoke.
Main Results:
- Reactive oxygen species activate MAPK pathways through specific tyrosine kinase and phosphatase modulation.
- Activated MAP proteins facilitate AP-1 signaling and interaction with other transcription factors.
- Tobacco smoke alters the redox status, leading to increased histone acetyltransferase and decreased deacetylase activity, thereby upregulating NF-κB and AP-1.
Conclusions:
- Tobacco smoke-induced oxidative stress is a primary driver for MAPK, NF-κB, and AP-1 activation.
- Epigenetic modifications, specifically altered histone acetylation, contribute to the intensified transcription of inflammatory mediators.
- Understanding these molecular pathways is crucial for addressing smoke-induced lung inflammation.
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