Polycyclic aromatic hydrocarbons induce IL-8 expression through nuclear factor kappaB activation in A549 cell line

Area of Science:

• Environmental Health
• Molecular Biology
• Toxicology

Background:

• Air pollution contributes to cardiopulmonary diseases, with airway inflammation playing a key role.
• Proinflammatory cytokines like interleukin-8 (IL-8) are central to airway inflammation.
• Previous studies linked asbestos and particulate air pollution to IL-8 expression and NF-kappaB activation.

Purpose of the Study:

• To investigate if polycyclic aromatic hydrocarbons (PAHs) alone can induce IL-8 expression.
• To examine the role of NF-kappaB activation in PAH-induced IL-8 expression.
• To assess the impact of inhibiting NF-kappaB on IL-8 transcription.

Main Methods:

• Used ELISA and Northern blot analysis to measure IL-8 expression.
• Employed gel shift assay to detect NF-kappaB activation.
• Utilized adenovirus-mediated IkappaBalpha overexpression in A549 cells to inhibit NF-kappaB.

Main Results:

• Both benzo(a)pyrene (B[a]P) and 1-nitropyrene (1-NP) significantly stimulated IL-8 gene expression in A549 cells.
• PAH exposure led to increased NF-kappaB activation.
• Overexpression of IkappaBalpha suppressed 1-NP-induced IL-8 transcription, implicating NF-kappaB.

Conclusions:

• PAHs, such as B[a]P and 1-NP, are sufficient to activate NF-kappaB independently.
• PAH-induced IL-8 gene expression is likely mediated through the NF-kappaB pathway.
• These findings highlight a direct mechanism by which airborne PAHs can promote airway inflammation.