Aryl Hydrocarbon Receptor (AhR) Limits the Inflammatory Responses in Human Lung Adenocarcinoma A549 Cells via Interference with NF-kappa B Signaling

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Authors	VAZQUEZ-GOMEZ Gerardo KARASOVÁ Martina TYLICHOVA Zuzana KABATKOVA Marketa HAMPL Aleš MATTHEWS Jason NECA Jiri CIGANEK Miroslav MACHALA Miroslav VONDRACEK Jan
Year of publication	2022
Type	Article in Periodical
Magazine / Source	Cells
MU Faculty or unit	Faculty of Science
Citation
Web	https://www.mdpi.com/2073-4409/11/4/707
Doi	http://dx.doi.org/10.3390/cells11040707
Keywords	AhR; inflammation; alveolar epithelial type II cellsNF-kappa B; prostaglandins; cytokines
Description	Apart from its role in the metabolism of carcinogens, the aryl hydrocarbon receptor (AhR) has been suggested to be involved in the control of inflammatory responses within the respiratory tract. However, the mechanisms responsible for this are only partially known. In this study, we used A549 cell line, as a human model of lung alveolar type II (ATII)-like cells, to study the functional role of the AhR in control of inflammatory responses. Using IL-1 beta as an inflammation inducer, we found that the induction of cyclooxygenase-2 and secretion of prostaglandins, as well as expression and release of pro-inflammatory cytokines, were significantly higher in the AhR-deficient A549 cells. This was linked with an increased nuclear factor-kappa B (NF-kappa B) activity, and significantly enhanced phosphorylation of its regulators, IKK alpha/beta, and their target I kappa B alpha, in the AhR-deficient A549 cells. In line with this, when we mimicked the exposure to a complex mixture of airborne pollutants, using an organic extract of reference diesel exhaust particle mixture, an exacerbated inflammatory response was observed in the AhR-deficient cells, as compared with wild-type A549 cells. Together, the present results indicate that the AhR may act as a negative regulator of the inflammatory response in the A549 model, via a direct modulation of NF-kappa B signaling. Its role(s) in the control of inflammation within the lung alveoli exposed to airborne pollutants, especially those which simultaneously activate the AhR, thus deserve further attention.