interleukin-8 and 2-butenal

Crotonaldehyde, a highly toxic α, β-unsaturated aldehyde, is a major component of cigarette smoke and a ubiquitous environmental pollutant. Crotonaldehyde exposure is known to have adverse effects on respiratory health, but the underlying mechanisms remain obscure. To examine the interaction between macrophages and airway epithelial cells after exposure to crotonaldehyde, BEAS-2B and A549 cells were treated with conditioned media from a human monocytic leukemia cell line (THP-1) cells stimulated with crotonaldehyde. We demonstrate that conditioned media from THP-1 cells stimulated with crotonaldehyde increased interleukin (IL)-8 production, enhanced nuclear factor (NF)-κB and AP-1 DNA-binding activity in BEAS-2B and A549 cells. Analysis of these conditioned media revealed marked increases in tumor necrosis factor (TNF)-α, IL-1β and IL-8 levels. Preincubation of conditioned media with either TNF-α- or IL-1β-neutralizing antibodies reduced IL-8 production. Furthermore, BEAS-2B and A549 cells directly treated with crotonaldehyde induced increase in IL-8 production. These data suggest that crotonaldehyde is capable of directly stimulating the production of IL-8 in both macrophages and airway epithelial cells. Crotonaldehyde-stimulated macrophages also amplify the inflammatory response by enhancing IL-8 release from airway epithelial cells mediated by NF-κB and AP-1 pathways through a mechanism involving TNF-α and IL-1β. These findings indicate that crotonaldehyde can cause lung inflammatory response via multiple mechanisms, and may contribute to chronic airway inflammation in smokers.

Topics: Aldehydes; Cell Culture Techniques; Cell Line; Culture Media, Conditioned; Epithelial Cells; Humans; Interleukin-8; Macrophages; NF-kappa B; Respiratory Mucosa; Signal Transduction; Tobacco Smoke Pollution; Transcription Factor AP-1

The transient receptor potential subfamily A member 1 (TRPA1) is a non-selective cation channel implicated in the pathogenesis of several airway diseases like asthma and chronic obstructive pulmonary disease (COPD). Most of the research on TRPA1 focuses on its expression and function in neuronal context; studies investigating non-neuronal expression of TRPA1 are lacking. In the present study, we show functional expression of TRPA1 in human lung fibroblast cells (CCD19-Lu) and human pulmonary alveolar epithelial cell line (A549). We demonstrate TRPA1 expression at both mRNA and protein levels in these cell types. TRPA1 selective agonists like allyl isothiocyanate (AITC), 4-hydroxynonenal (4-HNE), crotonaldehyde and zinc, induced a concentration-dependent increase in Ca+2 influx in CCD19-Lu and A549 cells. AITC-induced Ca+2 influx was inhibited by Ruthenium red (RR), a TRP channel pore blocker, and by GRC 17536, a TRPA1 specific antagonist. Furthermore, we also provide evidence that activation of the TRPA1 receptor by TRPA1 selective agonists promotes release of the chemokine IL-8 in CCD19-Lu and A549 cells. The IL-8 release in response to TRPA1 agonists was attenuated by TRPA1 selective antagonists. In conclusion, we demonstrate here for the first time that TRPA1 is functionally expressed in cultured human lung fibroblast cells (CCD19-Lu) and human alveolar epithelial cell line (A549) and may have a potential role in modulating release of this important chemokine in inflamed airways.

Topics: Aldehydes; Calcium; Calcium Channels; Cations, Divalent; Cells, Cultured; Chlorides; Dose-Response Relationship, Drug; Epithelial Cells; Fibroblasts; Humans; Interleukin-8; Isothiocyanates; Nerve Tissue Proteins; Ruthenium Red; Transient Receptor Potential Channels; TRPA1 Cation Channel; Zinc Compounds