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Abstract In order to clarify whether the mitochondrial dysfunction is closely related to the cell homeostasis maintenance after particulate matter (PM 2.5) exposure, oxidative, inflammatory, apoptotic and mitochondrial endpoints were carefully studied in human bronchial epithelial BEAS-2B, normal human bronchial epithelial (NHBE) and chronic obstructive pulmonary disease (COPD)-diseased human bronchial epithelial (DHBE) cells acutely or repeatedly exposed to air pollution-derived PM 2.5. Some modifications of the mitochondrial morphology were observed within all these cell models repeatedly exposed to the highest dose of PM 2.5. Dose- and exposure-dependent oxidative damages were reported in BEAS-2B, NHBE and particularly COPD-DHBE cells acutely or repeatedly exposed to PM 2.5. Nuclear factor erythroid 2-p45 related factor 2 (NRF2) gene expression and binding activity, together with the mRNA levels of some NRF2 target genes, were directly related to the number of exposures for the lowest PM 2.5 dose (i.e., 2 μg/cm2), but, surprisingly, inversely related to the number of exposures for the highest dose (i.e., 10 μg/cm2). There were dose- and exposure-dependent increases of both nuclear factor kappa-B (NF-κB) binding activity and NF-κB target cytokine secretion in BEAS-2B, NHBE and particularly COPD-DHBE cells exposed to PM 2.5. Mitochondrial ROS production, membrane potential depolarization, oxidative phosphorylation, and ATP production were significantly altered in all the cell models repeatedly exposed to the highest dose of PM 2.5. Collectively, our results indicate a cytosolic ROS overproduction, inducing oxidative damage and activating oxygen sensitive NRF2 and NF- k B signaling pathways for all the cell models acutely or repeatedly exposed to PM 2.5. However, one of the important highlight of our findings is that the prolonged and repeated exposure in BEAS-2B, NHBE and in particular sensible COPD-DHBE cells further caused an oxidative boost able to partially inactivate the NRF2 signaling pathway and to critically impair mitochondrial redox homeostasis, thereby producing a persistent mitochondrial dysfunction and a lowering cell energy supply. Graphical abstract Image 1 Highlights • Better knowledge of the critical role of mitochondrion in PM 2.5 -induced toxicity. • Mitochondrial ROS overproduction activates NRF2 and NF- k B signaling pathways. • Inactivated NRF2 signaling pathway impairs mitochondrial redox homeostasis. PM 2.5 -induced oxidative burst partially inactivates the NRF2 signaling pathway and critically impair mitochondrial redox homeostasis, thereby producing a persistent mitochondrial dysfunction and a lowering cell energy supply. [ABSTRACT FROM AUTHOR]

Even though clinical, epidemiological and toxicological studies have progressively provided a better knowledge of the underlying mechanisms by which air pollution-derived particulate matter (PM) exerts its harmful health effects, further in vitro studies on relevant cell systems are still needed. Hence, aiming of getting closer to the human in vivo conditions, primary human bronchial epithelial cells derived from normal subjects (NHBE) or sensitive chronic obstructive pulmonary disease (COPD)-diseased patients (DHBE) were differentiated at the air-liquid interface. Thereafter, they were repeatedly exposed to air pollution-derived PM 2.5 to study the occurrence of some relevant genetic and/or epigenetic endpoints. Concentration-, exposure- and season-dependent increases of OH-B[ a ]P metabolites in NHBE, and to a lesser extent, COPD-DHBE cells were reported; however, there were more tetra-OH-B[ a ]P and 8-OHdG DNA adducts in COPD-DHBE cells. No increase in primary DNA strand break nor chromosomal aberration was observed in repeatedly exposed cells. Telomere length and telomerase activity were modified in a concentration- and exposure-dependent manner in NHBE and particularly COPD-DHBE cells. There were a global DNA hypomethylation, a P16 gene promoter hypermethylation, and a decreasing DNA methyltransferase activity in NHBE and notably COPD-DHBE cells repeatedly exposed. Changes in site-specific methylation, acetylation, and phosphorylation of histone H3 (i.e., H3K4me3, H3K9ac, H3K27ac, and H3S10ph) and related enzyme activities occurred in a concentration- and exposure-dependent manner in all the repeatedly exposed cells. Collectively, these results highlighted the key role played by genetic and even epigenetic events in NHBE and particularly sensitive COPD-DHBE cells repeatedly exposed to air pollution-derived PM 2.5 and their different responsiveness. While these specific epigenetic changes have been already described in COPD and even lung cancer phenotypes, our findings supported that, together with genetic events, these epigenetic events could dramatically contribute to the shift from healthy to diseased phenotypes following repeated exposure to relatively low doses of air pollution-derived PM 2.5 . [ABSTRACT FROM AUTHOR]

While the knowledge of the underlying mechanisms by which air pollution-derived particulate matter (PM) exerts its harmful health effects is still incomplete, detailed in vitro studies are highly needed. With the aim of getting closer to the human in vivo conditions and better integrating a number of factors related to pre-existing chronic pulmonary inflammatory, we sought to develop primary cultures of normal human bronchial epithelial (NHBE) cells and chronic obstructive pulmonary disease (COPD)-diseased human bronchial epithelial (DHBE) cells, grown at the air-liquid interface. Pan-cytokeratin and MUC5AC immunostaining confirmed the specific cell-types of both these healthy and diseased cell models and showed they are closed to human bronchial epithelia. Thereafter, healthy and diseased cells were repeatedly exposed to air pollution-derived PM 4 at the non-cytotoxic concentration of 5 μg/cm 2 . The differences between the oxidative and inflammatory states in non-exposed NHBE and COPD-DHBE cells indicated that diseased cells conserved their specific physiopathological characteristics. Increases in both oxidative damage and cytokine secretion were reported in repeatedly exposed NHBE cells and particularly in COPD-DHBE cells. Diseased cells repeatedly exposed had lower capacities to metabolize the organic chemicals-coated onto the air-pollution-derived PM 4 , such as benzo[a]pyrene (B[a]P), but showed higher sensibility to the formation of OH-B[a]P DNA adducts, because their diseased state possibly affected their defenses. Differential profiles of epigenetic hallmarks (i.e., global DNA hypomethylation, P16 promoter hypermethylation, telomere length shortening, telomerase activation, and histone H3 modifications) occurred in repeatedly exposed NHBE and particularly in COPD-DHBE cells. Taken together, these results closely supported the highest responsiveness of COPD-DHBE cells to a repeated exposure to air pollution-derived PM 4 . The use of these innovative in vitro exposure systems such as NHBE and COPD-DHBE cells could therefore be consider as a very useful and powerful promising tool in the field of the respiratory toxicology, taking into account sensitive individuals. [ABSTRACT FROM AUTHOR]

The effects of iron nanoparticles on bryophytes ( Physcomitrella patens ) were studied following foliar exposure. We used iron nanoparticles (Fe–NP) representative of industrial emissions from the metallurgical industries. After a characterization of iron nanoparticles and the validation of nanoparticle internalization in cells, the effects (cytotoxicity, oxidative stress, lipid peroxidation of membrane) of iron nanoparticles were determined through the axenic culturing of Physcomitrella patens exposed at five different concentrations (5 ng, 50 ng, 500 ng, 5 µg and 50 µg per plant). Following exposure, the plant health, measured as ATP concentrations, was not impacted. Moreover, we studied oxidative stress in three ways: through the measure of reactive oxygen species (ROS) production, through malondialdehyde (MDA) production and also through glutathione regulation. At concentrations tested over a short period, the level of ROS, MDA and glutathione were not significantly disturbed. [ABSTRACT FROM AUTHOR]

This study deals with the health effects within a child population, neighbouring a landfill. After detecting metals in soil and air samples collected in the surroundings of the landfill and in a control site, we have studied: (i) levels of lead (Pb) and exposure biomarkers in blood and urine, (ii) oxidative stress biomarkers and (iii) renal injury by applying a set of early effect biomarkers. Levels of Pb were higher in the exposed site (i.e. 1129 mg/kg and 640 ng/m3 in soil and air samples, respectively) versus those in the control site (i.e. 14.3 mg/kg and 9.3 ng/m3 in soil and air samples, respectively). Pb impregnation and levels of delta-aminolevulinic acid in urine were influenced by the living site that shows the prevailingly alarming situation in the Mbeubeuss landfill. Malondialdehyde changes indicated Pb-induced excessive production of reactive oxygen species. Lactate dehydrogenase activities and proteinuria were found to be higher in the children living in the exposed site. These evidences may reveal the usefulness of these two effect biomarkers to monitor the kidney injury entailed by relatively low-environmental exposure to Pb. Overall, these results show that the Mbeubeuss landfill constitutes a real source of environmental and health risk, be it living or working on site, of the surrounding population, predominantly for children. [ABSTRACT FROM AUTHOR]

Abstract: This work concerns atmospheric particles (PM 2.5) collected in the surroundings of rural, urban and industrial areas. The investigation zone chosen for the study is Dunkirk (North of France), a highly industrialised city located along the North sea, where various activities are present such as metallurgy, petrol refineries and other chemical companies but also an important city with 210 000 inhabitants and two highly loaded motorways. Comparisons with a rural area were carried out. Physicochemical analysis of particulate matter was undertaken to propose parameters that could be used to distinguish the various sources and also to provide chemical elements for interpretation of future toxicological studies. This paper focuses on both organic and inorganic pollutants: Polycyclic Aromatic Hydrocarbons (PAH), paraffins, Volatile Organic Compounds (VOC), heavy metals and major soluble compounds (anionic and cationic). [Copyright &y& Elsevier]

Epidemiological studies have demonstrated the link between chronic exposure to particulate matter (PM), especially particles with an aerodynamic diameter lesser than 2.5 µm (PM), and lung cancer. Mechanistic investigations focus on the contribution of the various genotoxicants adsorbed onto the particles, and more particularly on polycyclic aromatic hydrocarbons or nitroaromatics. Most of the previous studies dealing with genotoxic and/or mutagenic measurements were performed on organic extracts obtained from PM collected in polluted areas. In contrast, we have evaluated genotoxic and mutagenic properties of urbano-industrial PM (PM) collected in Dunkerque (France). Thermally desorbed PM (dPM) was also comparatively studied. Suspensions of PM and dPM (5-50 µg per plate) were tested in Salmonella tester strains TA98, TA102 and YG1041 ± S9mix. Significant mutagenicity was observed for PM in YG1041 ± S9 mix. In strain TA102 - S9mix, a slight, but not significant dose-response increase was observed, for both PM and dPM. Genotoxic properties of PM and dPM were evaluated by the measurement of (1) 8-OHdG in A549 cells and (2) bulky DNA adducts on A549 cells and on human alveolar macrophages (AMs) in primary culture. A dose-dependant formation of 8-OHdG adducts was observed on A549 cells for PM and dPM, probably mainly attributed to the core of the particles. Bulky DNA adducts were observed only in AMs after exposure to PM and dPM. In conclusion, using relevant exposure models, suspension of PM induces a combination of DNA-interaction mechanisms, which could contribute to the induction of lung cancer in exposed populations. Copyright © 2010 John Wiley & Sons, Ltd. Genotoxic and mutagenic properties of suspensions of PM (PM) collected in Dunkerque (France) were evaluated together with their thermally desorbed counterpart (dPM). Significant mutagenicity was observed for PM only in Salmonella tester strains YG1041 ± S9 mix. For PM and dPM, a slight dose-response increase was observed in strain TA102 - S9mix. PM and dPM induced 8-OHdG adducts formation on A549 cells in a dose-dependent manner, together with bulky DNA adducts on human alveolar macrophages in primary culture. [ABSTRACT FROM AUTHOR]

The aim of this in situ study was to investigate the fatty acid (FA) composition and content in roots and shoots of Lolium perenne and Trifolium repens, grown under heavy metal stress (Cd, Pb, Zn). The composition of FA was quite similar for the two plants and the two organs; main FA were palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). For both plants, the major FA that characterized the roots was C18:2 whereas C18:3 was the prominent FA in shoots. For the first sampling (S1), in the roots of L. perenne and T. repens, polyunsaturated fatty acids (PUFA) were affected by metal contamination while, in the second sampling (S2), PUFA were affected in the shoots of the two plants. This alteration of PUFA was well correlated with the bioaccumulation factor of metals which decreased in roots and increased in shoots with the time. Moreover, a positive correlation was found between the PUFA decrease and the malondialdehyde (MDA) content, indicating the occurrence of a lipid peroxidation induced by the metal stress. [ABSTRACT FROM AUTHOR]

Abstract: The use of a vegetation cover for the management of heavy metal contaminated soils needs prior investigations on the plant species the best sustainable. In this work, behaviors of Trifolium repens and Lolium perenne, growing in a metal-polluted field located near a closed lead smelter, were investigated through Cd, Pb and Zn-plant metal concentrations and their phytotoxicity. In these plant species, metals were preferentially accumulated in roots than in shoots, as follow: Cd>Zn>Pb. Plant exposure to such metals induced oxidative stress in the considered organs as revealed by the variations in malondialdehyde levels and superoxide dismutase activities. These oxidative changes were closely related to metal levels, plant species and organs. Accordingly, L. perenne seemed to be more affected by metal-induced oxidative stress than T. repens. Taken together, these findings allow us to conclude that both the plant species could be suitable for the phytomanagement of metal-polluted soils. [Copyright &y& Elsevier]

Leaded-gasoline is probably the primary source of lead (Pb) exposure in Dakar (Senegal). The present cross-sectional study was undertaken to investigate the levels of Pb in Senegalese children and to present helpful data on the relationship between Pb levels and changes in biological markers of heme biosynthesis and oxidative stress. A total of 330 children, living since birth either in rural or urban areas (ie, Khombole (n = 162) and Dakar (n = 168), respectively) were included. During this cross-sectional study, the mean blood (B)-Pb level in all children was 7.32 ± 5.33 μg/dL, and was influenced by the area of residence and gender. In rural children, 27 subjects (16.7%), 18 boys (19.6%) and nine girls (12.9%), had a B-Pb level >10 μg Pb/dL, whereas 99 urban children (58.9%), respectively, 66 boys (71.8%) and 33 girls (43.4%), had alarmingly high B-Pb levels. Accordingly, urine delta-aminolevulinic acid levels were higher in children living in the urban area than in the rural areas (P <0.001), and closely correlated with the B-Pb levels (P <0.01). Moreover, glutathione peroxidase (GPx) activity, selenium (Se) level, glutathione reductase (GR) activity, and glutathione status were significantly influenced by area of residence and/or by gender. GPx activity and Se level were not only negatively correlated with B-Pb levels, but also positively correlated together (P <0.01). Taken together, the present results allow us to conclude that urban children have higher B-Pb levels than rural children, and that of these children, boys have higher B-Pb levels than girls, leading thereby to alterations of heme biosynthesis and pro-oxidant/antioxidant balance. We also suggest that exposure to Pb and the Pb-induced adverse effects merits attention and that the development of preventive actions are of increasing importance in Senegal. [ABSTRACT FROM AUTHOR]

In Senegal, as in many developing countries, traffic density is increasing in urban areas; in Dakar more than 50% of vehicles use gasoline. Yet the extent and real magnitude of the problem has neither been recognized nor assessed in these countries. Systemic data assessment of lead pollution and people's exposure are not well known in Senegal. This study was also designed to determine the impregnation levels of the lead released by the exhaust of cars and the changes of some early biological markers in Senegalese children. Blood lead (BPb) levels showed that all the children enrolled were exposed. However, lead exposure levels (from 34.7 to 145.8 μg/L) were less important for children living in rural areas (60.9 ± 18.3 μg/L) than for those living in urban areas (106.7 ± 16.9 μg/L). These changes could be correlated to the difference in the automobile traffic between both these regions (P < 0.001). BPb mean levels found in boys were higher than those in girls (P < 0.05). Despite elevated BPb levels, all values for blood zinc protoporphyrin and urine delta-aminolevulinic acid were within physiological ranges. In addition, variations in some biological markers of oxidative stress and renal disorders were seen; however, they must be confirmed by a future epidemiological study. [ABSTRACT FROM AUTHOR]

The knowledge of the underlying mechanisms by which particulate matter (PM) exerts its health effects is still incomplete since it may trigger various symptoms as some persons may be more susceptible than others. Detailed studies realized in more relevant in vitro models are highly needed. Healthy normal human bronchial epithelial (NHBE), asthma-diseased human bronchial epithelial (DHBE), and COPD-DHBE cells, differentiated at the air-liquid interface, were acutely or repeatedly exposed to fine (i.e., PM 2.5-0.18 , also called FP) and quasi-ultrafine (i.e., PM 0.18 , also called UFP) particles. Immunofluorescence labelling of pan-cytokeratin, MUC5AC, and ZO-1 confirmed their specific cell-types. Baselines of the inflammatory mediators secreted by all the cells were quite similar. Slight changes of TNFα, IL-1β, IL-6, IL-8, GM-CSF, MCP-1, and/or TGFα, and of H3K9 histone acetylation supported a higher inflammatory response of asthma- and especially COPD-DHBE cells, after exposure to FP and especially UFP. At baseline, 35 differentially expressed genes (DEG) in asthma-DHBE, and 23 DEG in COPD-DHBE, compared to NHBE cells, were reported. They were involved in biological processes implicated in the development of asthma and COPD diseases, such as cellular process (e.g., PLA2G4C, NLRP1, S100A5, MUC1), biological regulation (e.g., CCNE1), developmental process (e.g., WNT10B), and cell component organization and synthesis (e.g., KRT34 , COL6A1 , COL6A2). In all the FP or UFP-exposed cell models, DEG were also functionally annotated to the chemical metabolic process (e.g., CYP1A1 , CYP1B1 , CYP1A2) and inflammatory response (e.g., EREG). Another DEG, FGF-1 , was only down-regulated in asthma and specially COPD-DHBE cells repeatedly exposed. While RAB37 could help to counteract the down-regulation of FGF-1 in asthma-DHBE cells, the deregulation of FGR, WNT7B, VIPR1 , and PPARGC1A could dramatically contribute to make it worse in COPD-DHBE cells. Taken together, these data contributed to support the highest effects of UFP versus FP and highest sensitivity of asthma- and notably COPD-DHBE versus NHBE cells. • Innovative healthy and diseased 3D organo-typic mucocilary-phenotype models. • Experimental strategy of repeated exposures to ambient fine and ultrafine particles. • Better knowledge on the adverse effects of ambient fine and ultrafine particles. • Highest adverse effects of ultrafine vs fine particles. • Highest responsiveness of diseased vs healthy cell models. [ABSTRACT FROM AUTHOR]

• Better knowledge of the critical role of mitochondrion in FP and Q-UFP-induced lung toxicity. • Mitochondrial ROS overproduction and activation of NRF2-ARE signaling pathways. • Mitochondrial dynamics modifications in favor of accentuated fission process. • Mitochondrial quality control and metabolism dysfunctions as underlying mechanism of toxicity. • New insights into the physiopathology-induced by FP and mostly Q-UFP within the lung. Nowadays ambient particulate matter (PM) levels still regularly exceed the guideline values established by World Health Organization in most urban areas. Numerous experimental studies have already demonstrated the airway toxicity of the fine fraction of PM (FP), mainly triggered by oxidative stress-induced airway inflammation. However, only few studies have actually paid close attention to the ultrafine fraction of PM (UFP), which is likely to be more easily internalized in cells and more biologically reactive. Mitochondria are major endogenous sources of reactive oxygen species (ROS) through oxidative metabolism, and coordinate many critical cellular signaling processes. Mitochondria have been often studied in the context of PM toxicity and generally associated with apoptosis activation. However, little is known about the underlying adaptation mechanisms that could occur following exposure at sub-apoptotic doses of ambient PM. Here, normal human bronchial epithelial BEAS-2B cells were acutely or repeatedly exposed to relatively low doses (5 µg.cm−2) of FP (PM 2.5-0.18) or quasi-UFP (Q-UFP; PM 0.18) to better access the critical changes in mitochondrial morphology, functions, and dynamics. No significant cytotoxicity nor increase of apoptotic events were reported for any exposure. Mitochondrial membrane potential (ΔΨm) and intracellular ATP content were also not significantly impaired. After cell exposure to sub-apoptotic doses of FP and notably Q-UFP, oxidative phosphorylation was increased as well as mitochondrial mass, resulting in increased production of mitochondrial superoxide anion. Given this oxidative boost, the NRF2-ARE signaling pathway was significantly activated. However, mitochondrial dynamic alterations in favor of accentuated fission process were observed, in particular after Q-UFP vs FP, and repeated vs acute exposure. Taken together, these results supported mitochondrial quality control and metabolism dysfunction as an early lung underlying mechanism of toxicity, thereby leading to accumulation of defective mitochondria and enhanced endogenous ROS generation. Therefore, these features might play a key role in maintaining PM-induced oxidative stress and inflammation within lung cells, which could dramatically contribute to the exacerbation of inflammatory chronic lung diseases. The prospective findings of this work could also offer new insights into the physiopathology of lung toxicity, arguably initiate and/or exacerbate by acutely and rather repeated exposure to ambient FP and mostly Q-UFP. [ABSTRACT FROM AUTHOR]

• PM 2.5-0.18 and PM 0.18 induced primary DNA damage but no chromosome aberrations in immortalized cells. • PM 2.5 and PM 2.5-0.18 are devoid of in vitro genotoxic effect in NHBE primary cells. • PM 2.5 and PM 2.5-0.18 exhibit no in vivo genotoxic/mutagenic activity in our tested conditions. • Development of standardized methodologies for assessing the in vitro genotoxicity of PM is needed. • Epigenetics possibly implicated in pulmonary carcinogenesis should be investigated. Air pollution and particulate matter (PM) are classified as carcinogenic to humans. Pollutants evidence for public health concern include coarse (PM 10) and fine (PM 2.5) particles. However, ultrafine particles (PM 0.1) are assumed to be more toxic than larger particles, but data are still needed to better understand their mechanism of action. In this context, the aim of our work was to investigate the in vitro and in vivo genotoxic potential of fine (PM 2.5-018) and quasi ultra-fine (PM 0.18) particles from an urban-industrial area (Dunkirk, France) by using comet, micronucleus and/or gene mutation assays. In vitro assessment was performed with 2 lung immortalized cell lines (BEAS-2B and NCI-H292) and primary normal human bronchial epithelial cells (NHBE) grown at the air-liquid interface or in submerged conditions (5 µg PM/cm2). For in vivo assessment, tests were performed after acute (24 h, 100 µg PM/animal), subacute (1 month, 10 µg PM/animal) and subchronic (3 months, 10 µg PM/animal) intranasal exposure of BALB/c mice. In vitro , our results show that PM 2.5-018 and PM 0.18 induced primary DNA damage but no chromosomal aberrations in immortalized cells. Negative results were noted in primary cells for both endpoints. In vivo assays revealed that PM 2.5-018 and PM 0.18 induced no significant increases in DNA primary damage, chromosomal aberrations or gene mutations, whatever the duration of exposure. This investigation provides initial answers regarding the in vitro and in vivo genotoxic mode of action of PM 2.5-018 and PM 0.18 at moderate doses and highlights the need to develop standardized specific methodologies for assessing the genotoxicity of PM. Moreover, other mechanisms possibly implicated in pulmonary carcinogenesis, e.g. epigenetics, should be investigated. [ABSTRACT FROM AUTHOR]