Effects of Mainstream Cigarette Smoke on the Global Metabolome of Human Lung Epithelial Cells

Abstract

Metabolomics is a technology for identifying and quantifying numerous biochemicals across metabolic pathways. Using this approach, we explored changes in biochemical profiles of human alveolar epithelial carcinoma (A549) cells following in vitro exposure to mainstream whole smoke (WS) aerosol as well as to wet total particulate matter (WTPM) or gas/vapor phase (GVP), the two constituent phases of WS from 2R4F Kentucky reference cigarettes. A549 cells were exposed to WTPM or GVP (expressed as WTPM mass equivalent GVP volumes) at 0, 5, 25, or 50 microg/mL or to WS from zero, two, four, and six cigarettes for 1 or 24 h. Cell pellets were analyzed for perturbations in biochemical profiles, with named biochemicals measured, analyzed, and reported in a heat map format, along with biochemical and physiological interpretations (mSelect, Metabolon Inc.). Both WTPM and GVP exposures likely decreased glycolysis (based on decreased glycolytic intermediaries) and increased oxidative stress and cell damage. Alterations in the Krebs cycle and the urea cycle were unique to WTPM exposure, while induction of hexosamines and alterations in lipid metabolism were unique to GVP exposure. WS altered glutathione (GSH) levels, enhanced polyamine and pantothenate levels, likely increased beta-oxidation of fatty acids, and increased phospholipid degradation marked by an increase in phosphoethanolamine. GSH, glutamine, and pantothenate showed the most significant changes with cigarette smoke exposure in A549 cells based on principal component analysis. Many of the changed biochemicals were previously reported to be altered by cigarette exposure, but the global metabolomic approach offers the advantage of observing changes to hundreds of biochemicals in a single experiment and the possibility for new discoveries. The metabolomic approach may thus be used as a screening tool to evaluate conventional and novel tobacco products offering the potential to reduce risks of smoking.

Metabolomics Approach for Hazard Identification in Human Health Assessment of Environmental Chemicals

“…These data correlate with human microarray data that demonstrated an antioxidant response to cigarette smoke through the induction of genes associated with glutathione metabolism (Spira et al, 2004). Further, Vulimiri and colleagues (Vulimiri et al, 2009) observed increased levels (16.4-fold) of o-phosphoethanolamine, a marker of phospholipid degradation that may indicate cell membrane damage. Additional observations included increased arachidonic acid levels that may suggest an inflammatory response and markers (e.g.…”

“…There is a paucity of relevant metabolomic information for application to human health risk assessment of environmental chemicals. To date, the available literature suggests an informative role of metabolomics in understanding the mode of action of environmental xenobiotics (Vulimiri et al, 2011;Vulimiri et al, 2009). …”

“…Using the metabolomics approach in A549 human lung epithelial cells it has been shown that several biochemical pathways are altered by either the whole smoke (WS) or its component phases i.e. wet total particulate matter (WTPM) or gas/vapor phase (GVP) (Vulimiri et al, 2009). Exposures to the different phases lead to unique biochemical alterations in A549 cells.…”

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

“…Differences were observed between the effects of whole smoke and the gas/vapor phase from a single cigarette type on the metabolic pathways of human lung epithelial cells (Vulimiri et al, 2009), suggesting that cigarette smoke fractions can affect these pathways differentially. Exposure of NCI-H292 cells, a human lung epithelial cell line, to whole smoke demonstrated increases in expression of Muc5AC, an important form of mucin, and release of interleukin (IL)-6, IL-8, and MMP1 (Phillips et al, 2005).…”

LDL-Related Intolerance to Glucose, Diastolic Hypertension and Additive Effects of Smoking Were Found with Three Female Study Groups

“…Background art discloses that smoking triggers enzymatic beta-oxidation in mitochondrial compartments and degradation of the cellular defense system is shown with alveolar epithelial carcinoma cells [90]. Individual history of depression and/or dosage of psychopharmaca had to be carefully considered to guide persons at risk during long cessation periods [91].…”