Effects Of 10 Cigarette Smoke Condensates On Primary Human Airway Epithelial Cells By Comparative Gene And Cytokine Expression Studies

Abstract

Cigarettes vary in tobacco blend, filter ventilation, additives, and other physical and chemical properties, but little is known regarding potential differences in toxicity to a smoker's airway epithelia. We compared changes in gene expression and cytokine production in primary normal human bronchial epithelial cells following treatment for 18 h with cigarette smoke condensates (CSCs) prepared from five commercial and four research cigarettes, at doses of~4 mg/ml nicotine. Nine of the CSCs were produced under a standard International Organization for Standardization smoking machine regimen and one was produced by a more intense smoking machine regimen. Isolated messenger RNA (mRNA) was analyzed by microarray hybridization, and media was analyzed for secreted cytokines and chemokines. Twenty-one genes were differentially expressed by at least 9 of the 10 CSCs by more than twofold, including genes encoding detoxifying and antioxidant proteins. Cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and NAD(P)H dehydrogenase, quinone 1 (NQO-1) were selected for validation with quantitative real-time PCR (qRT-PCR) and Western blot analyses. NQO-1 expression determined with microarrays, qRT-PCR, and Western blotting differed among the CSC types, with good correlation among the different assays. CYP1A1 mRNA levels varied substantially, but there was little correlation with the protein levels. For each CSC, the three most induced and three most repressed genes were identified. These genes may be useful as markers of exposure to that particular cigarette type. Furthermore, differences in interleukin-8 secretion were observed. These studies lay the foundation for future investigations to analyze differences in the responses of in vivo systems to tobacco products marketed with claims of reduced exposure or reduced harm.

Bioinformatics Analysis of the Effects of Tobacco Smoke on Gene Expression

“…Some studies have reported that histologically normal large airway epithelial cells of smokers display allelic loss [ 10 ] and p53 mutations [ 11 ]. An in vitro study by Pickett et al [ 12 ] found that when a single source of human airway epithelial cells was exposed to the same dose of cigarette smoke condensate from 10 different cigarettes, 21 genes were altered by 9 of the 10 cigarettes. In addition, based on the transcriptome profiling, Spira et al [ 13 ] have indicated that smoking induces the expression of genes involved in redox stress and xenobiotic metabolism in the large airway epithelial cells.…”

Alzheimer's Disease and NQO1: Is there a Link?

“…Exposure of particulate phase of CS for 2h/d for days altered oxidative homeostasis in the lungs in Sprague Dawley rats as a result NQO1/actin ratio as well as NQO1 enzyme activity were increased [128]. Similarly, exposures of primary normal human bronchial epithelial cells to cigarette smoke condensates for 18 h strongly increased NQO1 expression compared to non-treated control cells [129]. However, with chronic exposure to cigarette smoke there is evidence of decreased Nrf2 activation and subsequent decrease in Nrf2-target genes including HO-1 and NQO1 [130,131].…”

Evaluation of Cytotoxic, Oxidative, and Pro-Inflammatory Effects of Aqueous Cigarette Smoke Extract on Human Monocytes: A Potential Model System for Assessment of Next-Generation Tobacco and Nicotine Products

“…The increased expression of NQO1 has been shown in human bronchial epithelial cells after stimulation with cigarette smoke condensate from commercial and research cigarettes for 18 h earlier. 49 Interestingly, expression of HMOX1 was increased only in THP-1 cells (Fig. 2B).…”