Cigarette smoke extract increases S-adenosylmethionine and cystathionine in human lung epithelial-like (A549) cells

The effect of cigarette smoke extract (CSE) on S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and sulfur amino acid metabolism was examined in human lung epithelial-like (A549) cells exposed to various CSE concentrations (2.5-100%) for 24 or 48 h. Intracellular SAM and SAM/SAH ratio were elevated after exposure to CSE for 48 h. Cell SAH content decreased, but the effect was not consistent. Cellular cystathionine, cysteine, and methionine levels were increased after CSE exposure for 48h. Sub-acute exposure to CSE induced increases in cellular SAM and SAM/SAH ratio. The transsulfuration pathway was likely activated by CSE since cystathionine increased, potentially contributing to the increased total intracellular GSH content.     

Cigarette smoke concentrate increases 8-epi-PGF2alpha and TGFbeta1 secretion in rat mesangial cells

Epidemiological studies have shown that cigarette smoke, an oxidant agent, is a risk factor for the development of diabetic nephropathy (DN), in which pathogenesis transforming growth factor beta(1) (TGFbeta(1)) plays a key role. In our experimental model we exposed mesangial cell cultures to cigarette smoke concentrate (CSC) to study the effect of smoking on the pathogenesis of DN. Thus, we analyzed the effect of CSC on TGFbeta(1) and lipid peroxidation (8-epi-PGF(2alpha)) in rat mesangial cells. Furthermore, since the protein kinase C (PKC) pathway appears to be a key factor for the enhanced production of TGFbeta(1), we also analyzed the effect of the selective PKCbeta inhibitor LY379196 on TGFbeta(1) response to CSC. CSC induced an increase of both TGFbeta(1) and 8-epi-PGF(2) compared to basal conditions (5 mM glucose). The CSC-induced increase in TGFbeta(1) secretion was significantly suppressed by LY379196. These data suggest that smoking could increase TGFbeta(1) production, probably due to oxidative stress and PKCbeta activation. This finding supports the concept that smoking is a risk factor for DN development.     

Smoke treatment triggers the release of a novel DNA damaging factor by lymphocytes

Abstact Organic fuel smoke is a hazardous agent, which pushes the cells towards“prooxidant state', leading to 4,46,400 strand breaks/cell/day as against 47,000 strand breaks/cell/day produced by constitutive oxygen radicals. This prooxidants scenario switches on a plethora of intercellular events. Here we report a novel DNA damaging factor released by lymphocytes, upon treatment with smoke condensate. Human lymphocytes, when exposed to cow dung cake smoke condensate, were found to release a low molecular weight factor into the media at 20 min of exposure. The conditioned media, displayed a propensity of inducing DNA damage in fresh, normal lymphocytes, which were not exposed to any damaging agent. The above DNA damaging effect of the conditioned media was not due to any residual presence of Polycyclic Aromatic Hydrocarbons, which were present in the smoke. The release of this factor was in correlation with the DNA damaging event, taking place in the cells. This secondary DNA damaging factor had a molecular weight less than 5 kd. The factor had the cell death inducing propensity when allowed to act on lymphocytes     

Smoke, Mulch, and Seed Broadcasting Effects on Woodland Restoration in Western Australia

Smoke, canopy‐derived mulch, and broadcast seeds were used to maximize the establishment of Banksia woodland species in sand quarries in Western Australia. Smoke, particularly aerosol smoke, had a positive effect on total seedling recruitment. Pre‐mined (woodland) sites showed a 42‐fold increase in total germinants and a 3‐fold increase in the number of species with aerosol smoke application. Post‐mined (restored) sites showed only a 3.6‐fold increase in total germinants and a 1.4‐fold increase in the number of species. Two water‐based smoke chemicals, DC10 (pH 4.5) and SC63 (pH 2.5), increased seedling recruitment at both sites but were not as effective in stimulating recruitment as aerosol smoke. Neither of the chemicals were effective in significantly increasing species richness. Application of aerosol smoke directly to seeds as a pretreatment before broadcasting had no effect on seedling recruitment. Broadcasting of seeds onto restoration sites significantly increased seedling abundance and richness. Application of a single layer of mulch from the canopy vegetation after seed broadcasting gave optimum seedling recruitment. Two layers of mulch significantly reduced recruitment, as did applying mulch before seed broadcasting. For broad‐scale restoration, the application of smoke on newly restored sites would be more effectively achieved using smoke water sprayed over the soil surface. Species that do not recruit from replaced topsoil could be effectively recovered from broadcast seed rather than from mulch.     

Dormancy break of celery (Apium graveolens L.) seeds by plant derived smoke extract

Seed dormancy of a highly-dormant cultivar of celery (Apium graveolens L.) was broken by combinations of plant-derived smoke extract or N⁶-benzyladenine (BA) and gibberellins A_4/7 (GA_4/7) in the dark at temperatures between 18 and 26°C. A less dormant cultivar which responded to GA_4/7 alone showed no additional response to smoke extract or BA. Neither smoke extract nor BA affected either cultivar in the dark in the absence of GA_4/7. The partial dormancy-breaking effect of short exposures to red-light was also enhanced by smoke extracts in this highly-dormant cultivar. The results suggest that smoke extracts act in a similar way to cytokinins, by enhancing gibberellin activity in the celery seed system.Abbreviations BA N⁶-benzyladenine - GA_4/7 A₄ and A₇ gibberellin mixture     

The dendritic cell niche in chronic obstructive pulmonary disease

The pulmonary innate immune system is heavily implicated in the perpetual airway inflammation and impaired host defense characterizing Chronic Obstructive Pulmonary Disease (COPD). The airways of patients suffering from COPD are infiltrated by various immune and inflammatory cells including macrophages, neutrophils, T lymphocytes, and dendritic cells. While the role of macrophages, neutrophils and T lymphocytes is well characterized, the contribution of dendritic cells to COPD pathogenesis is still the subject of emerging research. A paper by Botelho and colleagues in the current issue of Respiratory Research investigates the importance of dendritic cell recruitment in cigarette-smoke induced acute and chronic inflammation in mice. Dendritic cells of the healthy lung parenchyma and airways perform an important sentinel function and regulate immune homeostasis. During inflammatory responses the function and migration pattern of these cells is dramatically altered but the underlying mechanisms are incompletely understood. Botelho and colleagues demonstrate here the importance of IL-1R1/IL-1α related mechanisms including CCL20 production in cigarette-smoke induced recruitment of dendritic cells and T cell activation in the mouse lung.     

Evaluation of the oxidation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to toxic pyridinium cations by monoamine oxidase (MAO) enzymes and its use to search for new MAO inhibitors and protective agents

Monoamine oxidase (MAO) enzymes catalyze the oxidative deamination of amines and neurotransmitters and inhibitors of MAO are useful as neuroprotectants. This work evaluates the human MAO-catalyzed oxidation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a dopaminergic neurotoxin, to the directly-acting neurotoxic metabolites, 1-methyl-4-phenyl-2,3-dihydropyridinium (MPDP⁺) and 1-methyl-4-phenylpyridinium (MPP⁺) measured by High-Performance Liquid Chromatography (HPLC), and this approach is subsequently used as a new method for screening of MAO inhibitors and protective agents. Oxidation of MPTP by human MAO-B was more efficient than by MAO-A. R-Deprenyl, a known neuroprotectant, norharman (β-carboline), 5-nitroindazole and menadione (vitamin K3) inhibited MAO-B and reduced the formation of toxic pyridinium cations. Clorgyline and the β-carbolines, harman and norharman, inhibited the oxidation of MPTP by MAO-A. Cigarette smoke, as well as the naturally occurring β-carbolines (norharman and harman) isolated from smoke and coffee inhibited the oxidation of MPTP by MAO-B and/or MAO-A, suggesting protective effects against MPTP. The results show the suitability of the approach used to search for new MAO inhibitors with eventual neuroprotective activity.     

Combined genetic polymorphism and risk for development of lung cancer

Susceptibility to lung cancer has been shown to be modulated by host specific factors. Inheritance of different polymorphic cytochrome P450s (CYPs) and the glutathione S-transferases (GSTs) which affect metabolism of environmental toxicants may play a key role in individual susceptibility. Although individual polymorphic genes have been reported to be associated with development of lung cancer, little is known about the combined effects of several genes in carcinogenesis. From our study of 54 lung cancer patients and 50 matched controls, we observed that a combination of several versions of ‘unfavorable' metabolizing genes (CYP2D6, CYP2E1, GSTM1 and GSTT1) is strongly associated with lung cancer. The relative risk for the different combinations of these genotypes ranged between 1.3 and 14, with higher risk involving the activating genes. The duration and intensity of heavy smoking (expressed in pack-years) are the most important determinant for the development of lung cancer. For example, the estimated risk for development of lung cancer associated with smoking >30 pack-years is represented by an odds ratio=6.65; 95% CL=2.3–19.9 irrespective of an individual's genotype, whereas for smoking between >30 and <50 pack-years, odds ratio=4.5; 95% CL=1.37–15; and for smoking >50 pack-years, odds ratio=30; 95% CL=5.7–114. On the other hand, smoking of less than 30 pack-years is associated with an increased risk in the presence of the polymorphic genes (odds ratio=2.5; 95% CL=0.32–54). The results of our study indicate that the inheritance of multiple ‘unfavorable' genotypes, especially activating genes, is a crucial predisposing factor for the development of lung cancer from cigarette smoking. In addition, the genes may cause moderate smokers who would normally outlive the deleterious effects of smoking to develop lung cancer. The information can therefore be used to target individuals for prevention of health problems.     

Validation of urinary thiocyanate as a biomarker of tobacco smoking

Thiocyanate ion (SCN) is the major detoxication product of cyanide, which is converted to SCN by a thiosulphate sulphurtransferase, mainly in hepatic mitochondria. Low-level cyanide exposure for man is caused by factors such as dietary intake of cyanogenic glucosides, tobacco smoking, drug administration and occupational exposure to organic nitriles. Urinary SCN concentration was determined through a commercial kit for the analysis of cyanide in water. Spot urine samples were collected at 7:30 h and 12:30 h, from 99 healthy male white-collar office workers (non-smokers n=72, smokers n=27). Comparison of SCN excretion values did not show any difference between the morning and midday samples. The SCN median value of non-smokers was 24 μmol l^-1 (range 9-24 μmol l^-1) and was statistically different from that of smokers (SCN = 92 μmol l^-1, range 33-275 μmol l^-1) (     

Comparative seed germination ecology of Austrostipa compressa and Ehrharta calycina (Poaceae) in a Western Australian Banksia woodland

Austrostipa compressa, a native ephemeral of southwest Western Australia was stimulated to germinate under a range of temperatures, in the presence of light, and exposure to smoke-water. This combination of environmental cues results in winter-maximum germination in immediate postfire and disturbed-soil environments of this Mediterranean-type climate. In contrast, Ehrharta calycina, an introduced perennial grass from southern Africa that has invaded Banksia woodlands, germinated under a wide range of temperature and light conditions, but showed no promotive response to smoke-water. Although A. compressa seeds tolerated heat shock better than E. calycina, the self-burial mechanism of A. compressa seeds ensures protection from fire. High-intensity fire could have a greater impact on E. calycina, as the seeds of this species tend to accumulate in the top of the soil profile where they are more susceptible to high temperatures. Although seeds of E. calycina are more susceptible to high temperatures, survival of mature individuals by postfire resprouting ensures continued survival in native woodlands. Estimates of soil seed bank densities showed extreme variability, but some recently burnt areas of the Yule Brook Botany Reserve contained up to 8000 seed m^?2 of A. compressa and nearly 75 000 seeds m^?2 of E. calycina. Viable soil seed bank densities of A. compressa are reduced with time-since-last fire, but areas of greater than 45 years since the last fire, still contained up to 119 seeds m^?2. In both species, only about half their soil seed bank germinates following fire, thus ensuring the potential for later recruitment. Massive soil seed populations of E. calycina in native Banksia woodlands pose a major problem to management of this plant community type.