Prooxidant and proinflammatory potency of air pollution particulate matter (PM₂.₅₋₀.₃) produced in rural, urban, or industrial surroundings in human bronchial epithelial cells (BEAS-2B)

Toxicological effects of solvent-extracted organic matter associated with PM2.5 on human bronchial epithelial cell line NL-20

The heterogeneity and complexity of solvent-extracted organic matter associated with PM2.5 (SEOM-PM2.5) is well known; however, there is scarce information on its biological effects in human cells. This work aimed to evaluate the effect of SEOM-PM2.5 collected in northern Mexico City during the cold-dry season (November 2017) on NL-20 cells, a human bronchial epithelial cell line. The SEOM obtained accounted for 15.5% of the PM2.5 mass and contained 21 polycyclic aromatic hydrocarbons (PAHs). The cell viability decreased following exposure to SEOM-PM2.5, and there were noticeable morphological changes such as increased cell size and the presence of cytoplasmic vesicles in cells treated with 5-40 μg/mL SEOM-PM2.5. Exposure to 5 μg/mL SEOM-PM2.5 led to several alterations compared with the control cells, including the induction of double-stranded DNA breaks based (p < 0.001); nuclear fragmentation and an increased mitotic index (p < 0.05); 53BP1 staining, a marker of DNA repair by non-homologous end-joining (p < 0.001); increased BiP protein expression; and reduced ATF6, IRE1α, and PERK gene expression. Conversely, when exposed to 40 μg/mL SEOM-PM2.5, the cells showed an increase in reactive oxygen species formation (p < 0.001), BiP protein expression (p < 0.05), and PERK gene expression (p < 0.05), indicating endoplasmic reticulum stress. Our data suggest concentration-dependent toxicological effects of SEOM-PM2.5 on NL-20 cells, including genotoxicity, genomic instability, and endoplasmic reticulum stress.

A causal relationship between particulate matter 2.5 and obesity and its related indicators: a Mendelian randomization study of European ancestry

Background

In recent years, the prevalence of obesity has continued to increase as a global health concern. Numerous epidemiological studies have confirmed the long-term effects of exposure to ambient air pollutant particulate matter 2.5 (PM2.5) on obesity, but their relationship remains ambiguous.

Methods

Utilizing large-scale publicly available genome-wide association studies (GWAS), we conducted univariate and multivariate Mendelian randomization (MR) analyses to assess the causal effect of PM2.5 exposure on obesity and its related indicators. The primary outcome given for both univariate MR (UVMR) and multivariate MR (MVMR) is the estimation utilizing the inverse variance weighted (IVW) method. The weighted median, MR-Egger, and maximum likelihood techniques were employed for UVMR, while the MVMR-Lasso method was applied for MVMR in the supplementary analyses. In addition, we conducted a series of thorough sensitivity studies to determine the accuracy of our MR findings.

Results

The UVMR analysis demonstrated a significant association between PM2.5 exposure and an increased risk of obesity, as indicated by the IVW model (odds ratio [OR]: 6.427; 95% confidence interval [CI]: 1.881-21.968; P FDR = 0.005). Additionally, PM2.5 concentrations were positively associated with fat distribution metrics, including visceral adipose tissue (VAT) (OR: 1.861; 95% CI: 1.244-2.776; P FDR = 0.004), particularly pancreatic fat (OR: 3.499; 95% CI: 2.092-5.855; PFDR =1.28E-05), and abdominal subcutaneous adipose tissue (ASAT) volume (OR: 1.773; 95% CI: 1.106-2.841; P FDR = 0.019). Furthermore, PM2.5 exposure correlated positively with markers of glucose and lipid metabolism, specifically triglycerides (TG) (OR: 19.959; 95% CI: 1.269-3.022; P FDR = 0.004) and glycated hemoglobin (HbA1c) (OR: 2.462; 95% CI: 1.34-4.649; P FDR = 0.007). Finally, a significant negative association was observed between PM2.5 concentrations and levels of the novel obesity-related biomarker fibroblast growth factor 21 (FGF-21) (OR: 0.148; 95% CI: 0.025-0.89; P FDR = 0.037). After adjusting for confounding factors, including external smoke exposure, physical activity, educational attainment (EA), participation in sports clubs or gym leisure activities, and Townsend deprivation index at recruitment (TDI), the MVMR analysis revealed that PM2.5 levels maintained significant associations with pancreatic fat, HbA1c, and FGF-21.

Conclusion

Our MR study demonstrates conclusively that higher PM2.5 concentrations are associated with an increased risk of obesity-related indicators such as pancreatic fat content, HbA1c, and FGF-21. The potential mechanisms require additional investigation.

PM2.5 Extracts Induce INFγ-Independent Activation of CIITA, MHCII, and Increases Inflammation in Human Bronchial Epithelium

The capacity of particulate matter (PM) to enhance and stimulate the expression of pro-inflammatory mediators has been previously demonstrated in non-antigen-presenting cells (human bronchial epithelia). Nonetheless, many proposed mechanisms for this are extrapolated from known canonical molecular pathways. This work evaluates a possible mechanism for inflammatory exacerbation after exposure to PM2.5 (from Puerto Rico) and CuSO4, using human bronchial epithelial cells (BEAS-2B) as a model. The induction of CIITA, MHCII genes, and various pro-inflammatory mediators was investigated. Among these, the phosphorylation of STAT1 Y701 was significantly induced after 4 h of PM2.5 exposure, concurrent with a slight increase in CIITA and HLA-DRα mRNA levels. INFγ mRNA levels remained low amidst exposure time, while IL-6 levels significantly increased at earlier times. IL-8 remained low, as expected from attenuation by IL-6 in the known INFγ-independent inflammation pathway. The effects of CuSO4 showed an increase in HLA-DRα expression after 8 h, an increase in STAT1 at 1 h, and RF1 at 8 h We hypothesize and show evidence that an inflammatory response due to PM2.5 extract exposure in human bronchial epithelia can be induced early via an alternate non-canonical pathway in the absence of INFγ.

Association Between Long‑Term Exposure to Air Pollution and the Rate of Mortality After Hip Fracture Surgery in Patients Older Than 60 Years: Nationwide Cohort Study in Taiwan

BACKGROUND

To enhance postoperative patient survival, particularly in older adults, understanding the predictors of mortality following hip fracture becomes paramount. Air pollution, a prominent global environmental issue, has been linked to heightened morbidity and mortality across a spectrum of diseases. Nevertheless, the precise impact of air pollution on hip fracture outcomes remains elusive.

OBJECTIVE

This retrospective study aims to comprehensively investigate the profound influence of a decade-long exposure to 12 diverse air pollutants on the risk of post-hip fracture mortality among older Taiwanese patients (older than 60 years). We hypothesized that enduring long-term exposure to air pollution would significantly elevate the 1-year mortality rate following hip fracture surgery.

METHODS

From Taiwan's National Health Insurance Research Database, we obtained the data of patients who underwent hip fracture surgery between July 1, 2003, and December 31, 2013. Using patients' insurance registration data, we estimated their cumulative exposure levels to sulfur dioxide (SO2), carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), particulate matter having a size of <10 μm (PM10), particulate matter having a size of <2.5 μm (PM2.5), nitrogen oxides (NOX), nitrogen monoxide (NO), nitrogen dioxide (NO2), total hydrocarbons (THC), nonmethane hydrocarbons (NMHC), and methane (CH4). We quantified the dose-response relationship between these air pollutants and the risk of mortality by calculating hazard ratios associated with a 1 SD increase in exposure levels over a decade.

RESULTS

Long-term exposure to SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 demonstrated significant associations with heightened all-cause mortality risk within 1 year post hip fracture surgery among older adults. For older adults, each 1 SD increment in the average exposure levels of SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 corresponded to a substantial escalation in mortality risk, with increments of 14%, 49%, 18%, 12%, 41%, 33%, 38%, 20%, 9%, and 26%, respectively. We further noted a 35% reduction in the hazard ratio for O3 exposure suggesting a potential protective effect, along with a trend of potentially protective effects of CO2.

CONCLUSIONS

This comprehensive nationwide retrospective study, grounded in a population-based approach, demonstrated that long-term exposure to specific air pollutants significantly increased the risk of all-cause mortality within 1 year after hip fracture surgery in older Taiwanese adults. A reduction in the levels of SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 may reduce the risk of mortality after hip fracture surgery. This study provides robust evidence and highlights the substantial impact of air pollution on the outcomes of hip fractures.

The biological interplay between air pollutants and miRNAs regulation in cancer

Air pollution, especially fine particulate matter (PM2.5, with an aerodynamic diameter of less than 2.5 μm), represents a risk factor for human health. Many studies, regarding cancer onset and progression, correlated with the short and/or long exposition to PM2.5. This is mainly mediated by the ability of PM2.5 to reach the pulmonary alveoli by penetrating into the blood circulation. This review recapitulates the methodologies used to study PM2.5 in cellular models and the downstream effects on the main molecular pathways implicated in cancer. We report a set of data from the literature, that describe the involvement of miRNAs or long noncoding RNAs on the main biological processes involved in oxidative stress, inflammation, autophagy (PI3K), cell proliferation (NFkB, STAT3), and EMT (Notch, AKT, Wnt/β-catenin) pathways. microRNAs, as well as gene expression profile, responds to air pollution environment modulating some key genes involved in epigenetic modification or in key mediators of the biological processes described below. In this review, we provide some scientific evidences about the thigh correlation between miRNAs dysregulation, PM2.5 exposition, and gene pathways involved in cancer progression.

Selenium-Enriched Soybean Peptides as Novel Organic Selenium Compound Supplements: Inhibition of Occupational Air Pollution Exposure-Induced Apoptosis in Lung Epithelial Cells

The occupational groups exposed to air pollutants, particularly PM2.5, are closely linked to the initiation and advancement of respiratory disorders. The aim of this study is to investigate the potential protective properties of selenium-enriched soybean peptides (Se-SPeps), a novel Se supplement, in mitigating apoptosis triggered by PM2.5 in A549 lung epithelial cells. The results indicate a concentration-dependent reduction in the viability of A549 cells caused by PM2.5, while Se-SPeps at concentrations of 62.5-500 µg/mL showed no significant effect. Additionally, the Se-SPeps reduced the production of ROS, proinflammatory cytokines, and apoptosis in response to PM2.5 exposure. The Se-SPeps suppressed the PM2.5-induced upregulation of Bax/Bcl-2 and caspase-3, while also restoring reductions in p-Akt in A549 cells. The antiapoptotic effects of Se-SPeps have been found to be more effective compared to SPeps, SeMet, and Na2SeO3 when evaluated at an equivalent protein or Se concentration. Our study results furnish evidence that supports the role of Se-SPeps in reducing the harmful effects of PM2.5, particularly in relation to its effect on apoptosis, oxidative stress, and inflammation.

Oxidative stress and inflammation induced by air pollution-derived PM2.5 persist in the lungs of mice after cessation of their sub-chronic exposure

More than 7 million early deaths/year are attributable to air pollution. Current health concerns are especially focused on air pollution-derived particulate matter (PM). Although oxidative stress-induced airway inflammation is one of the main adverse outcome pathways triggered by air pollution-derived PM, the persistence of both these underlying mechanisms, even after exposure cessation, remained poorly studied. In this study, A/JOlaHsd mice were also exposed acutely (24 h) or sub-chronically (4 weeks), with or without a recovery period (12 weeks), to two urban PM2.5 samples collected during contrasting seasons (i.e., autumn/winter, AW or spring/summer, SS). The distinct intrinsic oxidative potentials (OPs) of AW and SS PM2.5, as evaluated in acellular conditions, were closely related to their respective physicochemical characteristics and their respective ability to really generate ROS over-production in the mouse lungs. Despite the early activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) cell signaling pathway by AW and, in a lesser degree, SS PM2.5, in the murine lungs after acute and sub-chronic exposures, the critical redox homeostasis was not restored, even after the exposure cessation. Accordingly, an inflammatory response was reported through the activation of the nuclear factor-kappa B (NF-κB) cell signaling pathway activation, the secretion of cytokines, and the recruitment of inflammatory cells, in the murine lungs after the acute and sub-chronic exposures to AW and, in a lesser extent, to SS PM2.5, which persisted after the recovery period. Taken together, these original results provided, for the first time, new relevant insights that air pollution-derived PM2.5, with relatively high intrinsic OPs, induced oxidative stress and inflammation, which persisted admittedly at a lower level in the lungs after the exposure cessation, thereby contributing to the occurrence of molecular and cellular adverse events leading to the development and/or exacerbation of future chronic inflammatory lung diseases and even cancers.

ANRIL regulating the secretion of Muc5ac induced by atmospheric PM2.5 via NF-κB pathway in Beas-2B cells

PM2.5 can cause airway inflammation and promote the excessive secretion of mucin 5ac (Muc5ac), which can further induce many respiratory diseases. Antisense non-coding RNA in the INK4 locus (ANRIL) might regulate the inflammatory responses mediated by nuclear factor kappa-B (NF-κB) signaling pathway. Beas-2B cells were used to clarify the role of ANRIL in the secretion of Muc5ac induced by PM2.5 . The siRNA was used to silence ANRIL expression. Normal and gene silenced Beas-2B cells were respectively exposed to different doses of PM2.5 for 6, 12, and 24 h. The survival rate of Beas-2B cells was detected by methyl thiazolyl tetrazolium (MTT) assay. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and Muc5ac levels were determined by enzyme linked immunosorbent assay (ELISA). The expression levels of NF-κB family genes and ANRIL were detected by real time polymerase chain reaction (PCR). The levels of NF-κB family proteins and NF-κB family phosphorylated proteins were determined using Western blot. Immunofluorescence experiments were performed to observe the nuclear transposition of RelA. PM2.5 exposure increased the levels of Muc5ac, IL-1β and TNF-α, and ANRIL gene expression (p < .05). With the dose and time of PM2.5 exposure increasing, the protein levels of inhibitory subunit of nuclear factor kappa-B alpha (IκB-α), RelA, and NF-κB1 decreased, the protein levels of phosphorylated RelA (p-RelA) and phosphorylated NF-κB1 (p-NF-κB1) increased, and RelA nuclear translocation increased, which indicated that the NF-κB signaling pathway was activated (p < .05). Silencing ANRIL could decrease the levels of Muc5ac, IL-1β, TNF-α, decrease NF-κB family genes expression, inhibit the degradation of IκB-α and the activation of NF-κB pathway (p < .05). ANRIL played a regulatory role in the secretion of Muc5ac and the inflammation induced by atmospheric PM2.5 via NF-κB pathway in Beas-2B cells. ANRIL could be a target for prevention and treatment of the respiratory diseases caused by PM2.5 .

HPLC Analysis and Risk Assessment of 15 Priority PAHs in Human Blood Serum of COPD Patient from Urban and Rural Areas, Iasi (Romania)

One of the leading risk factors for environmental health problems is air pollution. The World Health Organization (WHO) reports that this risk factor is associated with one of every nine deaths worldwide. Epidemiological studies conducted in this field have shown a solid connection between respiratory pathology and polycyclic aromatic hydrocarbon (PAH) exposure. COPD and asthma are respiratory diseases that were shown to have a strong association with exposure to PAHs. The purpose of the present study was to assess the serum levels of 15 PAHs in 102 COPD patients and to evaluate the results according to the residence environment of the investigated subjects. Analyses were carried out using a high-performance liquid chromatograph Nexera X2-Shimadzu Japan, which was equipped with an LC-30AD pump and an SIL-30AC autosampler. Spiked matrices, procedure blanks, spiked controls, and calibration standards in the acetonitrile were used as quality-assurance samples. Benzo(a)pyrene is the main representative of PAHs and was determined in higher concentrations in subjects with COPD versus the control group from the urban area (0.90/0.47 ng/mL) and rural area (0.73/0.44 ng/mL). The values obtained for the Benzo(a)pyrene-equivalent factor indicate a higher carcinogenic potential for patients diagnosed with COPD in urban areas compared to those in rural areas. These results could be due to traffic and vehicle emissions. This research identifies the need for legislative action to decrease semi-volatile organic compounds, especially PAHs, mainly in urban cities, in order to improve environmental management and health conditions.

Cholinergic anti-inflammatory pathway mediates diesel exhaust PM2.5-induced pulmonary and systemic inflammation

Previous research has indicated that the cholinergic anti-inflammatory pathway (CAP) can regulate the duration and intensity of inflammatory responses. A wide range of research has demonstrated that PM_2.5 exposure may induce various negative health effects via pulmonary and systemic inflammations. To study the potential role of the CAP in mediating PM_2.5-induced effects, mice were treated with vagus nerve electrical stimulation (VNS) to activate the CAP before diesel exhaust PM_2.5 (DEP) instillation. Analysis of pulmonary and systemic inflammations in mice demonstrated that VNS significantly reduced the inflammatory responses triggered by DEP. Meanwhile, inhibition of the CAP by vagotomy aggravated DEP-induced pulmonary inflammation. The flow cytometry results showed that DEP influenced the CAP by altering the Th cell balance and macrophage polarization in spleen, and in vitro cell co-culture experiments indicated that this DEP-induced change on macrophage polarization may act via the splenic CD4⁺ T cells. To further confirm the effect of alpha7 nicotinic acetylcholine receptor (α7nAChR) in this pathway, mice were then treated with α7nAChR inhibitor (α-BGT) or agonist (PNU282987). Our results demonstrated that specific activation of α7nAChR with PNU282987 effectively alleviated DEP-induced pulmonary inflammation, while specific inhibition of α7nAChR with α-BGT exacerbated the inflammatory markers. The present study suggests that PM_2.5 have an impact on the CAP, and CAP may play a critical function in mediating PM_2.5 exposure-induced inflammatory response. AVAILABILITY OF DATA AND MATERIALS: The datasets used and/or analyzed during the present study are available from the corresponding author on reasonable request.

Unique regulatory roles of ncRNAs changed by PM2.5 in human diseases

PM_2.5 is a type of particulate matter with an aerodynamic diameter smaller than 2.5 µm, and exposure to PM_2.5 can adversely damage human health. PM_2.5 may impair health through oxidative stress, inflammatory reactions, immune function alterations and chromosome or DNA damage. Through increasing in-depth studies, researchers have found that noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs), circular RNAs (circRNAs) as well as long noncoding RNAs (lncRNAs), might play significant roles in PM_2.5-related human diseases via some of the abovementioned mechanisms. Therefore, in this review, we mainly discuss the regulatory function of ncRNAs altered by PM_2.5 in human diseases and summarize the potential molecular mechanisms. The findings reveal that these ncRNAs might induce or promote diseases via inflammation, the oxidative stress response, cell autophagy, apoptosis, cell junction damage, altered cell proliferation, malignant cell transformation, disruption of synaptic function and abnormalities in the differentiation and status of immune cells. Moreover, according to a bioinformatics analysis, the altered expression of potential genes caused by these ncRNAs might be related to the development of some human diseases. Furthermore, some ncRNAs, including lncRNAs, miRNAs and circRNAs, or processes in which they are involved may be used as biomarkers for relevant diseases and potential targets to prevent these diseases. Additionally, we performed a meta-analysis to identify more promising diagnostic ncRNAs as biomarkers for related diseases.

The Road to Malignant Cell Transformation after Particulate Matter Exposure: From Oxidative Stress to Genotoxicity

In cells, oxidative stress is an imbalance between the production/accumulation of oxidants and the ability of the antioxidant system to detoxify these reactive products. Reactive oxygen species (ROS), cause multiple cellular damages through their interaction with biomolecules such as lipids, proteins, and DNA. Genotoxic damage caused by oxidative stress has become relevant since it can lead to mutation and play a central role in malignant transformation. The evidence describes chronic oxidative stress as an important factor implicated in all stages of the multistep carcinogenic process: initiation, promotion, and progression. In recent years, ambient air pollution by particulate matter (PM) has been cataloged as a cancer risk factor, increasing the incidence of different types of tumors. Epidemiological and toxicological evidence shows how PM-induced oxidative stress could mediate multiple events oriented to carcinogenesis, such as proliferative signaling, evasion of growth suppressors, resistance to cell death, induction of angiogenesis, and activation of invasion/metastasis pathways. In this review, we summarize the findings regarding the involvement of oxidative and genotoxic mechanisms generated by PM in malignant cell transformation. We also discuss the importance of new approaches oriented to studying the development of tumors associated with PM with more accuracy, pursuing the goal of weighing the impact of oxidative stress and genotoxicity as one of the main mechanisms associated with its carcinogenic potential.

Oxidative stress response in pulmonary cells exposed to different fractions of PM2.5-0.3 from urban, traffic and industrial sites

The aim of this work was to study the relationship between oxidative stress damages and particulate matter (PM) chemical composition, sources, and PM fractions. PM_2.5-0.3 (PM with equivalent aerodynamic diameter between 2.5 and 0.3 μm) were collected at urban, road traffic and industrial sites in the North of France, and were characterized for major and minor chemical species. Four different fractions (whole PM_2.5-0.3, organic, water-soluble and non-extractable matter) were considered for each of the PM_2.5-0.3 samples from the three sites. After exposure of BEAS-2B cells to the four different fractions, oxidative stress was studied in cells by quantifying reactive oxygen species (ROS) accumulation, oxidative damage to proteins (carbonylated proteins), membrane alteration (8-isoprostane) and DNA damages (8-OHdG). Whole PM_2.5-0.3 was capable of inducing ROS overproduction and caused damage to proteins at higher levels than other fractions. Stronger cell membrane and DNA damages were found associated with PM and organic fractions from the urban site. ROS overproduction was correlated with level of expression of carbonylated proteins, DNA damages and membrane alteration markers. The PM_2.5-0.3 collected under industrial influence appears to be the less linked to cell damages and ROS production in comparison with the other influences.

Selenium-enriched soybean peptides pretreatment attenuates lung injury in mice induced by fine particulate matters (PM2.5) through inhibition of TLR4/NF-κB/IκBα signaling pathway and inflammasome generation

This study aimed to identify and prepare peptides from selenium (Se)-enriched soybeans and determine whether dietary Se-enriched soybean peptides (Se-SPep) could inhibit lung injury in mice induced by fine particulate matter 2.5 (PM2.5). BALB/c mice were randomly divided into six groups. The mice in the prevention groups were pretreated with 378 mg kg^-1 of Se-SPep, soybean peptides (SPep), and Se-enriched soybean protein (Se-SPro), respectively, for four weeks. The mice in the PM2.5 exposure group received concentrated PM2.5 (15 μg per day mice) for 1 h daily from the third week for two weeks. The results showed that the leukocyte and cytokine (IL-1β, IL-6, TNF-α) levels in the bronchoalveolar lavage fluid (BALF) of the PM2.5 exposure group were higher than those in the control group. Se-SPep pretreatment decreased the IL-1β, IL-6, and TNF-α levels compared with the PM2.5 exposure group. Additionally, Se-SPep pretreatment inhibited TLR4/NF-κB/IκBα and NLRP3/ASC/caspase-1 protein expression in the lungs. In conclusion, Se-SPep pretreatment may protect the lungs of the mice against PM2.5-induced inflammation, suggesting that Se-SPep represents a potential preventative agent to inhibit PM2.5-induced lung injury.

Pathogenic Mechanisms of Secondary Organic Aerosols

Air pollution represents a major health problem and an economic burden. In recent years, advances in air pollution research has allowed particle fractionation and identification of secondary organic aerosol (SOA). SOA is formed from either biogenic or anthropogenic emissions, through a mass transfer from the gaseous mass to the particulate phase in the atmosphere. They can have deleterious impact on health and the mortality of individuals with chronic inflammatory diseases. The pleiotropic effects of SOA could involve different and interconnected pathogenic mechanisms ranging from oxidative stress, inflammation, and immune system dysfunction. The purpose of this review is to present recent findings about SOA pathogenic roles and potential underlying mechanisms focusing on the lungs; the latter being the primary exposed organ to atmospheric pollutants.

Development of a standardized in vitro approach to evaluate microphysical, chemical, and toxicological properties of combustion-derived fine and ultrafine particles

Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking their biological effects to their multiple properties, which are important determinants of toxicity. Our aim is to propose an interdisciplinary approach to study fine (FP) and ultrafine (UFP) particles, generated in a controlled manner using a miniCAST (Combustion Aerosol Standard) soot generator used with two different operating conditions (CAST1 and CAST3). The chemical characterization was performed by an untargeted analysis using ultra-high resolution mass spectrometry. In conjunction with this approach, subsequent analysis by gas chromatography-mass spectrometry (GC-MS) was performed to identify polycyclic aromatic hydrocarbons (PAH). CAST1 enabled the generation of FP with a predominance of small PAH molecules, and CAST3 enabled the generation of UFP, which presented higher numbers of carbon atoms corresponding to larger PAH molecules. Healthy normal human bronchial epithelial (NHBE) cells differentiated at the air-liquid interface (ALI) were directly exposed to these freshly emitted FP and UFP. Expression of MUC5AC, FOXJ1, OCLN and ZOI as well as microscopic observation confirmed the ciliated pseudostratified epithelial phenotype. Study of the mass deposition efficiency revealed a difference between the two operating conditions, probably due to the morphological differences between the two categories of particles. We demonstrated that only NHBE cells exposed to CAST3 particles induced upregulation in the gene expression of IL-8 and NQO1. This approach offers new perspectives to study FP and UFP with stable and controlled properties.

Effect of Atmospheric Aging on Soot Particle Toxicity in Lung Cell Models at the Air–Liquid Interface: Differential Toxicological Impacts of Biogenic and Anthropogenic Secondary Organic Aerosols (SOAs)

Background:

Secondary organic aerosols (SOAs) formed from anthropogenic or biogenic gaseous precursors in the atmosphere substantially contribute to the ambient fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] burden, which has been associated with adverse human health effects. However, there is only limited evidence on their differential toxicological impact.

Objectives:

We aimed to discriminate toxicological effects of aerosols generated by atmospheric aging on combustion soot particles (SPs) of gaseous biogenic (β-pinene) or anthropogenic (naphthalene) precursors in two different lung cell models exposed at the air–liquid interface (ALI).

Methods:

Mono- or cocultures of lung epithelial cells (A549) and endothelial cells (EA.hy926) were exposed at the ALI for 4 h to different aerosol concentrations of a photochemically aged mixture of primary combustion SP and β-pinene (SOAβPIN-SP) or naphthalene (SOANAP-SP). The internally mixed soot/SOA particles were comprehensively characterized in terms of their physical and chemical properties. We conducted toxicity tests to determine cytotoxicity, intracellular oxidative stress, primary and secondary genotoxicity, as well as inflammatory and angiogenic effects.

Results:

We observed considerable toxicity-related outcomes in cells treated with either SOA type. Greater adverse effects were measured for SOANAP-SP compared with SOAβPIN-SP in both cell models, whereas the nano-sized soot cores alone showed only minor effects. At the functional level, we found that SOANAP-SP augmented the secretion of malondialdehyde and interleukin-8 and may have induced the activation of endothelial cells in the coculture system. This activation was confirmed by comet assay, suggesting secondary genotoxicity and greater angiogenic potential. Chemical characterization of PM revealed distinct qualitative differences in the composition of the two secondary aerosol types.

Discussion:

In this study using A549 and EA.hy926 cells exposed at ALI, SOA compounds had greater toxicity than primary SPs. Photochemical aging of naphthalene was associated with the formation of more oxidized, more aromatic SOAs with a higher oxidative potential and toxicity compared with β-pinene. Thus, we conclude that the influence of atmospheric chemistry on the chemical PM composition plays a crucial role for the adverse health outcome of emissions. https://doi.org/10.1289/EHP9413

Characterization of airborne PAHs and metals associated with PM10 fractions collected from an urban area of Sri Lanka and the impact on airway epithelial cells

Airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are significant contributors leading to many human health issues. Thus, this study was designed to perform chemical analysis and biological impact of airborne particulate matter 10 (PM₁₀) in the World heritage City of Kandy City in Sri Lanka. 12 priority PAHs and 34 metals, including 10 highly toxic HMs were quantified. The biological effects of organic extracts were assayed using an in vitro primary porcine airway epithelial cell culture model. Cytotoxicity, DNA damage, and gene expressions of selected inflammatory and cancer-related genes were also assessed. Results showed that the total PAHs ranged from 3.062 to 36.887 ng/m³. The metals were dominated by Na > Ca > Mg > Al > K > Fe > Ti, while a few toxic HMs were much higher in the air than the existing ambient air quality standards. In the bioassays, a significant cytotoxicity (p < 0.05) was observed at 300 μg/mL treatment, and significant (p < 0.05) DNA damages were noted in all treatment groups. All genes assessed were found to be significantly up-regulated (p < 0.05) after 24 h of exposure and after 48 h, only TGF-β1 and p53 did not significantly up-regulate (p < 0.05). These findings confirm that the Kandy city air contains potential carcinogenic and mutagenic compounds and thus, exposure to Kandy air may increase the health risks and respiratory tract-related anomalies.

Airborne particulate matter induces oxidative damage, DNA adduct formation and alterations in DNA repair pathways

Air pollution, which includes particulate matter (PM), is classified in group 1 as a carcinogen to humans by the International Agency for Research in Cancer. Specifically, PM exposure has been associated with lung cancer in patients living in highly polluted cities. The precise mechanism by which PM is linked to cancer has not been completely described, and the genotoxicity induced by PM exposure plays a relevant role in cell damage. In this review, we aimed to analyze the types of DNA damage and alterations in DNA repair pathways induced by PM exposure, from both epidemiological and toxicological studies, to comprehend the contribution of PM exposure to carcinogenesis. Scientific evidence supports that PM exposure mainly causes oxidative stress by reactive oxygen species (ROS) and the formation of DNA adducts, specifically by polycyclic aromatic hydrocarbons (PAH). PM exposure also induces double-strand breaks (DSBs) and deregulates the expression of some proteins in DNA repair pathways, precisely, base and nucleotide excision repairs and homologous repair. Furthermore, specific polymorphisms of DNA repair genes could lead to an adverse response in subjects exposed to PM. Nevertheless, information about the effects of PM on DNA repair pathways is still limited, and it has not been possible to conclude which pathways are the most affected by exposure to PM or if DNA damage is repaired properly. Therefore, deepening the study of genotoxic damage and alterations of DNA repair pathways is needed for a more precise understanding of the carcinogenic mechanism of PM.

Toxicological impact of organic ultrafine particles (UFPs) in human bronchial epithelial BEAS-2B cells at air-liquid interface

Air pollution has significant health effects worldwide, and airborne particles play a significant role in these effects. Ultrafine particles (UFPs) have an aerodynamic diameter of 0.1 μm or less, can penetrate deep into the respiratory tree, and are more toxic due to their large specific surface area, which should adsorb organic compounds. The aim of this study is to show the toxicological effects of UFPs with high organic content at low dose on BEAS-2B cells through at air-liquid interface (ALI) exposure using a Vitrocell® technology and a miniCAST (Combustion Aerosol Standard) generator. In conjunction with this approach, chemical analysis of particles and gas phase was performed to evaluate the presence of polycyclic aromatic hydrocarbons (PAHs). Chemical analyses confirmed the presence of PAHs in UFPs. With this experimental setup, exposure of the BEAS-2B cells induced neither cytotoxicity nor mitochondrial dysfunction. However, an increase of oxidative stress was observed, as assessed through Nrf2, NQO1, HO-1, CuZnSOD, MnSOD, and Catalase gene expression, together with significant induction of genes related to xenobiotic metabolism CYP1A1 and CYP1B1. Negative regulation of inflammatory genes expression (IL-6 and IL-8) was present three hours after the exposition to the UFPs. Taken together, this experimental approach, using repeatable conditions, should help to clarify the mechanisms by which organic UFPs induce toxicological effects.

Potential cytotoxicity of trace elements and polycyclic aromatic hydrocarbons bounded to particulate matter: a review on in vitro studies on human lung epithelial cells

A large number of studies have been conducted for clarifying toxicological mechanisms of particulate matter (PM) aimed to investigate the physicochemical properties of PM and providing biological endpoints such as inflammation, perturbation of cell cycle, oxidative stress, or DNA damage. However, although several studies have presented some effects, there is still no consensus on the determinants of biological responses. This review attempts to summarize all past research conducted in recent years on the physicochemical properties of environmental PM in different places and the relationship between different PM components and PM potential cytotoxicity on the human lung epithelial cells. Among 447 papers with our initial principles, a total of 50 articles were selected from 1986 to April 2020 based on the chosen criteria for review. According to the results of selected studies, it is obvious that cytotoxicity in human lung epithelial cells is created both directly or indirectly by transition metals (such as Cu, Cr, Fe, Zn), polycyclic aromatic hydrocarbons (PAH), and ions that formed on the surface of particles. In the selected studies, the findings of the correlation analysis indicate that there is a significant relationship between cell viability reduction and secretion of inflammatory mediators. As a result, it seems that the observed biological responses are related to the composition and the physicochemical properties of the PMs. Therefore, the physicochemical properties of PM should be considered when explaining PM cytotoxicity, and long-term research data will lead to improved strategies to reduce air pollution.

The effect of toxic components on metabolomic response of male SD rats exposed to fine particulate matter

PM_2.5 pollution was associated with numerous adverse health effects. However, PM_2.5 induced toxic effects and the relationships with toxic components remain largely unknown. To evaluate the metabolic toxicity of PM_2.5 at environmentally relevant doses, investigate the seasonal variation of PM_2.5 induced toxicity and the relationship with toxic components, a combination of general pathophysiological tests and metabolomics analysis was conducted in this study to explore the response of SD rats to PM_2.5 exposure. The result of general toxicology analysis revealed unconspicuous toxicity of PM_2.5 under environmental dose, but winter PM_2.5 at high dose caused severe histopathological damage to lung. Metabolomic analysis highlighted significant metabolic disorder induced by PM_2.5 even at environmentally relevant doses. Lipid metabolism and GSH metabolism were primarily influenced by PM_2.5 exposure due to the high levels of heavy metals. In addition, high levels of organic compounds such as PAHs, PCBs and PCDD/Fs in winter PM_2.5 bring multiple overlaps on the toxic pathways, resulting in larger pulmonary toxicity and metabolic toxicity in rats than summer.

Toxicity of selected airborne nitrophenols on eukaryotic cell membrane models

Nitroaromatics belong to the group of toxic components of aerosol particles and atmospheric hydrometeors that enter the atmosphere through biomass burning and fuel combustion. In the present work, we report on the cytotoxic effects of a 2-, 3- and 4-nitrophenol mixture on a model eukaryotic-like cell membrane and compared it with in vitro cellular models BEAS-2B (immortalized bronchial epithelial cells) and A549 (cancerous alveolar epithelial cells). A selected model biomembrane comprised of DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine), DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) was studied. The electrochemical-based method, combined with atomic force microscopy (AFM) and phase-contrast microscopy imaging, allowed to get insights into the mechanism of cellular function disruption caused by airborne nitrophenols. The efficacy of the method is supported by the data obtained from in vitro experiments performed on cell models. The nitrophenol mixture exhibited cytotoxic effects at concentrations above 100 μg mL^-1, as demonstrated by phase-contrast microscopy in real lung cell lines. Electrochemical impedance spectroscopy (EIS) revealed the formation of membrane defects at a nitrophenol concentration of 200 μg mL^-1. AFM imaging confirmed the model membrane disintegration and phospholipids rearrangement in the presence of nitrophenols. These observations indicate that particle-bound nitrophenols induce substantial changes in cell membranes and make them more permeable to aerosol, resulting in major cellular damage in the lungs when inhaled. The study provides initial evidence of cellular membrane damage induced by three important nitrated phenols present in the environment.

Transcriptomic analysis identifies dysregulated genes and functional networks in human small airway epithelial cells exposed to ambient PM2.5

Cellular models exhibiting human physiological features of pseudostratified columnar epithelia, provide a more realistic approach for elucidating detailed mechanisms underlying PM_2.5-induced pulmonary toxicity. In this study, we characterized the barrier and mucociliary functions of differentiated human small airway epithelial cells (SAECs), cultured at the air-liquid interface (ALI). Due to the presence of mucociliary protection, particle internalization was reduced, with a concomitant decrease in cytotoxicity in differentiated S-ALI cells, as compared to conventional submerged SAEC cultures. After 24-hour exposure to PM_2.5 surrogates, 117 up-regulated genes and 156 down-regulated genes were detected in S-ALI cells, through transcriptomic analysis using the Affymetrix Clariom™ S Human Array. Transcription-level changes in >60 signaling pathways, were revealed by functional annotation of the 273 differentially expressed genes, using the PANTHER Gene List Analysis. These pathways are involved in multiple cellular processes, that include inflammation and apoptosis. Exposure to urban PM_2.5 led to complex responses in airway epithelia, including a net induction of downstream pro-inflammatory and pro-apoptotic responses. Collectively, this study highlights the importance of using the more advanced ALI model rather than the undifferentiated submerged model, to avoid over-assessment of inhaled particle toxicity in human. The results of our study also suggest that reduction of ambient PM_2.5 concentrations would have a protective effect on respiratory health in humans.

Characterization of organic aerosols in PM1 and their cytotoxicity in an urban roadside area in Hong Kong

Organic compounds in fine particles play major roles in cardiopulmonary diseases. A study was conducted to determine the characteristics and cytotoxicity of organic aerosols (OA) in an urban roadside area in Hong Kong. Chemical components in nonrefractory submicron aerosol (NR-PM₁) were observed using a Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM), and the chemical profile of organic compounds in NR-PM₁ was examined with filter-based approach. Associations between cytotoxicity and organic sources and compositions were evaluated. NR-PM₁ contributed to 84% of the PM₁ concentrations. The NR-PM₁ was composed of organics (55 ± 15%), followed by sulfate (21 ± 9%), ammonium (13 ± 6%), nitrate (10 ± 6%) and chloride (1 ± 1%). Three major organic sources were identified using positive matrix factorization, namely primary organic aerosol (POA, 40 ± 19%), more-oxidized oxygenated OA (MO-OOA, 32 ± 22%) and less-oxidized oxygenated OA (LO-OOA, 28 ± 19%). Variations in organic groups, including alkanes, hopanes, steranes, polycyclic aromatic hydrocarbons (PAHs), oxy-PAHs (OPAHs), and fatty acids, demonstrated that traffic and cooking emissions were dominant pollution sources in this roadside station. Human lung alveolar epithelial (A549) cells were exposed to PM₁, revealing increases in lactate dehydrogenase (LDH), reactive oxygen species (ROS), and interlukin-6 (IL-6), which indicated the occurrence of inflammatory and oxidative responses. POA was significantly associated with ROS and IL-6, and alkanes, hopanes, steranes, PAHs and OPAHs, and fatty acids presented medium to high correlations with LDH and IL-6, demonstrating the importance of primary emissions and organic compounds in cytotoxicity. This study demonstrated that organic compounds emitted from traffic and cooking play critical roles in PM-induced oxidative stress and inflammation in urban areas.

Reactive oxygen species production and inflammatory effects of ambient PM2.5 -associated metals on human lung epithelial A549 cells "one year-long study": The Delhi chapter

The fine particulate matter (PM_2.5) was collected at academic campus of Indian Institute of Technology, Delhi, India from January-December 2017. The PM_2.5 samples were analysed for carcinogenic (Cd, Cr, As, Ni, and Pb) and non-carcinogenic (V, Cu, Zn, Fe) trace metals and their elicited effects on carcinoma epithelial cell line A549. Toxicological testing was done with ELISA kit. Same analyses were repeated for standard reference material (NIST-1648a) represents urban particulate matter. The student-t test and spearman correlation were used for data analysis. The seasonality in PM_2.5 mass concentration and chemical composition showed effect on biological outcomes. The PM_2.5 in post-monsoon and winter had higher amount of trace metals compared to mass collected in pre-monsoon and monsoon. Following the trend in PM mass concentration significantly (p < 0.5) lower cell viability was observed in post-monsoon and winter compared to other two seasons. NIST UPM 1648(a) samples always had higher cytotoxicity compared to ambient PM_2.5 Delhi sample. Strong association of Chromium, Nickel, Cadmium, and Zinc was observed with cell viability and reactive oxygen species (ROS) production. In winter IL-6, IL-8 production were 2.8 and 3 times higher than values observed in post-monsoon and 53 and 9 times higher than control. In winter season trace metals As, Cu, Fe, in pre-monsoon Cr, Ni, As, Pb, V, and Fe, in post-monsoon Cd and V strongly correlated with ROS generation. ROS production in winter and pre-monsoon seasons found to be 2.6 and 1.3 times higher than extremely polluted post-monsoon season which had 2 to 3 times higher PM_2.5 concentration compared to winter and pre-monsoon. The result clearly indicated that the presence of Fe in winter and pre-monsoon seasons catalysed the ROS production, probably OH˙ radical caused high cytokines production which influenced the cell viability reduction, while in post-monsoon PM majorly composed of Pb, As, Fe and Cu and affected by photochemical smog formation showed significant association between ROS production with cell viability. Overall, in Delhi most toxic seasons for respiratory system are winter and post-monsoon and safest season is monsoon.

Cytotoxicity and Potential Pathway to Vascular Smooth Muscle Cells Induced by PM2.5 Emitted from Raw Coal Chunks and Clean Coal Combustion

Coal combustion emits a large amount of PM_2.5 (particulate matters with aerodynamic diameters less than 2.5 μm) and causes adverse damages to the cardiovascular system. In this study, emissions from anthracite and bitumite were examined. Red mud (RM) acts as an additive and is mixed in coal briquettes with a content of 0-10% as a single variable to demonstrate the reduction in the PM_2.5 emissions. Burnt in a regulated combustion chamber, the 10% RM-containing bitumite and anthracite briquettes showed 52.3 and 18.6% reduction in PM_2.5, respectively, compared with their chunk coals. Lower cytotoxicity (in terms of oxidative stresses and inflammation factors) was observed for PM_2.5 emitted from the RM-containing briquettes than those from non-RM briquettes, especially for the bitumite groups. Besides, the results of western blotting illustrated that the inhibition of NF-κB and MAPK was the potential pathway for the reduction of cytokine levels by the RM addition. The regression analyses further demonstrated that the reduction was attributed to the lower emissions of transition metals (i.e., Mn) and PAHs (i.e., acenaphthene). This pilot study provides solid evidence for the cytotoxicity to vascular smooth muscle cells induced by PM_2.5 from coal combustion and potential solutions for reducing the emission of toxic pollutants from human health perspectives.

Mitochondrial alterations triggered by repeated exposure to fine (PM2.5-0.18) and quasi-ultrafine (PM0.18) fractions of ambient particulate matter

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.

Toxicological appraisal of the chemical fractions of ambient fine (PM2.5-0.3) and quasi-ultrafine (PM0.3) particles in human bronchial epithelial BEAS-2B cells

New toxicological research is still urgently needed to improve the current knowledge about the induction of some underlying mechanisms of toxicity by the different chemical fractions of ambient particulate matter (PM). This in vitro study sought also to better evaluate and compare the respective toxicities of fine particles (PM_2.5-0.3) and their inorganic and organic chemical fractions, and the respective toxicities of the organic chemical fractions of PM_2.5-0.3 and quasi-ultrafine particles (PM_0.3). Human bronchial epithelial BEAS-2B cells were also exposed for 6-48 h to relatively low doses of PM_2.5-0.3 and their organic extractable (OEM_2.5-0.3) and non-extractable (NEM_2.5-0.3) fractions, and the organic extractable fraction (OEM_0.3) of PM_0.3. We reported that not only PM_2.5-0.3, but also, to a lesser extent, its inorganic chemical fraction, NEM_2.5-0.3, and organic chemical fraction, OEM_2.5-0.3, were able to significantly induce ROS overproduction and oxidative damage notwithstanding the early activation of NRF2 signaling pathway. Moreover, for any exposure, inflammatory and apoptotic events were noticed. Similar results were observed in BEAS-2B cells exposed to OEM_0.3, rich of polycyclic aromatic hydrocarbons and their nitrated and oxygenated derivatives. In BEAS-2B cells exposed for 24 and 48 h to OEM_2.5-0.3 and OEM_0.3, to a higher extent, there was an alteration of the levels of some critical proteins even though crucial for the autophagy rather than a real reduction of autophagy. It is noteworthy that the toxicological effects were equal or mostly higher in BEAS-2B cells exposed for 6 and/or 24 h to PM_2.5-0.3 from those exposed to NEM_2.5-0.3 or OEM_2.5-0.3, and in BEAS-2B cells exposed for 6 and/or mostly 24 h to OEM_0.3 from those exposed to OEM_2.5-0.3. Taken together, these results revealed the higher potentials for toxicity, closely linked to their respective physical and chemical characteristics, of PM_2.5-0.3 vs NEM_2.5-0.3 and/or OEM_2.5-0.3, and OEM_0.3 vs OEM_2.5-0.3.

Short-term exposure to air pollution (PM2.5) induces hypothalamic inflammation, and long-term leads to leptin resistance and obesity via Tlr4/Ikbke in mice

A previous study demonstrated that a high-fat diet (HFD), administered for one-three-days, induces hypothalamic inflammation before obesity’s established, and the long term affects leptin signaling/action due to inflammation. We investigate whether exposure to particulate matter of a diameter of ≤2.5 μm (PM_2.5) in mice fed with a chow diet leads to similar metabolic effects caused by high-fat feeding. Compared to the filtered air group (FA), one-day-exposure-PM_2.5 did not affect adiposity. However, five-days-exposure-PM_2.5 increased hypothalamic microglia density, toll-like-receptor-4 (Tlr4), and the inhibitor-NF-kappa-B-kinase-epsilon (Ikbke) expression. Concurrently, fat mass, food intake (FI), and ucp1 expression in brown adipose tissue were also increased. Besides, decreased hypothalamic STAT3-phosphorylation and Pomc expression were found after twelve-weeks-exposure-PM_2.5. These were accompanied by increased FI and lower energy expenditure (EE), leading to obesity, along with increased leptin and insulin levels and HOMA. Mechanistically, the deletion of Tlr4 or knockdown of the Ikbke gene in the hypothalamus was sufficient to reverse the metabolic outcomes of twelve-weeks-exposure-PM_2.5. These data demonstrated that short-term exposure-PM_2.5 increases hypothalamic inflammation, similar to a HFD. Long-term exposure-PM_2.5 is even worse, leading to leptin resistance, hyperphagia, and decreased EE. These effects are most likely due to chronic hypothalamic inflammation, which is regulated by Tlr4 and Ikbke signaling.

Lead and cadmium blood levels and transfer to milk in cattle reared in a mining area

The presence of heavy metals in milk is a public health problem that negatively effects human health, especially infant health. This study evaluated the concentration levels of lead (Pb) and cadmium (Cd) in blood and its transfer to the milk of 20 cows in production in a rural community near the La Oroya Metallurgical Complex in Peru, which has emitted fine particulate matter for more than 90 years. Validated protocols were used for sample collection. The samples were analyzed by atomic absorption spectrophotometry. The results of the analysis indicated that the levels, in mg/kg, of Pb in blood and milk were 0.38 ± 0.041 and 0.58 ± 0.018, respectively; Pb in milk was 54% higher than that in blood (P < 0.01). Cd levels, in mg/kg, in blood and milk were 0.016 ± 0.002 and 0.02 ± 0.007, respectively; milk had 28% more Cd than did blood (P < 0.05). The results for Pb in milk were compared with the Codex Alimentarius standard (0.002 mg/kg); the mean concentration of Pb in milk was 29 times higher than the acceptable limit, and the mean concentration of Cd was 2 times higher than the acceptable limit of the Romanian standard (0.01 mg/kg). The result could be attributed to the impact of environmental pollution by mining waste. In Peru, there are no norms for maximum Pb and Cd values, and the establishment of maximum value norms for these metals in milk is suggested.

Toxicity of fine and quasi-ultrafine particles: Focus on the effects of organic extractable and non-extractable matter fractions

To date no study has been able to clearly attribute the observed toxicological effects of atmospheric particles (PM) to a specific class of components. The toxicity of both the organic extractable matter (OEM_2.5-0.3) and non-extractable matter (NEM_2.5-0.3) of fine particles (PM_2.5-0.3) was compared to that of PM_2.5-0.3 in its entirety on normal human epithelial bronchial BEAS-2B cells in culture. The specific effect of the quasi-ultrafine fraction (PM_0.3) was assessed, by comparing the responses of cells exposed to the PM_2.5-0.3 and PM_0.3 organic extractable matter, OEM_2.5-0.3 and OEM_0.3 respectively. Chemically, PAH, O-PAH, and N-PAH were respectively 43, 17, and 4 times more concentrated in PM_0.3 than in PM_2.5-0.3, suggesting thereby a predominant influence of anthropogenic activities and combustion sources. BEAS-2B cells exposed to PM_2.5-0.3, NEM_2.5-0.3, EOM_2.5-0.3 and OEM_0.3 lead to different profiles of expression of selected genes and proteins involved in the metabolic activation of PAH, O-PAH, and N-PAH, and in the genotoxicity pathways. Specifically, OEM_0.3 was the most inducer for phase I and phase II enzymes implicated in the metabolic activation of PAH (AHR, AHRR, ARNT, CYP1A1, CYP1B1, EPHX-1, GSTA-4) thereby producing the highest DNA damage, felt by ATR and, thereafter, a cascade of protein phosphorylation (CHK1/CHK2/MDM2) closely related to the cell cycle arrest (P21 and P53 induction). This study underlined the crucial role played by the organic chemicals present in PM_0.3. These results should be considered in any future study looking for the main chemical determinants responsible for the toxicity of ambient fine PM.

Impact of Sea Breeze Dynamics on Atmospheric Pollutants and Their Toxicity in Industrial and Urban Coastal Environments

Sea breeze (SB) phenomena may strongly influence air quality and lead to important effects on human health. In order to study the impact of SB dynamics on the properties and toxicity of aerosols, an atmospheric mobile unit was deployed during a field campaign performed in an urbanized and industrialized coastal area in Northern France. This unit combines aerosol samplers, two scanning lidars (Doppler and elastic) and an air-liquid interface (ALI, Vitrocell®) in vitro cell exposure device. Our study highlights that after the passage of an SB front, the top of the atmospheric boundary layer collapses as the thermal internal boundary layer (TIBL) develops, which leads to high aerosol extinction coefficient values (>0.4 km−1) and an increase of PM2.5 and NOx concentrations in the SB current. The number-size distribution of particles indicates a high proportion of fine particles (with diameter below 500 nm), while the volume-size distribution shows a major mode of coarse particles centered on 2–3 µm. Individual particle analyses performed by cryo-transmission scanning electron microscopy (cryo-TSEM)-EDX highlights that submicronic particles contained a high fraction of secondary compounds, which may result from nucleation and/or condensation of condensable species (vapors or gaseous species after photo-oxidation). Secondary aerosol (SA) formation can be enhanced in some areas, by the interaction between the SB flow and the upper continental air mass, particularly due to the effect of both turbulence and temperature/humidity gradients between these two contrasting air masses. Potential areas of SA formation are located near the ground, during the SB front passage and in the vicinity of the SB current top. During the sea breeze event, an increase in the oxidative stress and inflammation processes in exposed lung cells, compared to the unexposed cells, can also be seen. In some instances, short singularity periods are observed during SB, corresponding to a double flow structure. It consists of two adjacent SB currents that induce an important increase of the TIBL top, improving the pollutants dispersion. This is associated with a substantial decrease of aerosol mass concentrations.

A prospective pilot study of the T-lymphocyte response to fine particulate matter exposure

Exposure to air pollution is associated with increased morbidity and mortality. Once the fine atmospheric particulate matter (FP) is inhaled, some of its compounds can pass through the lungs and reach the bloodstream where they can come into contact with immune cells. Exposure to FP particularly affects sensitive populations such as the elderly. Aging affects the immune system, making the elderly more vulnerable. The project aims to determine the effects of FP exposure on human T cells while looking for biomarkers associated with exposure. Blood samples from 95 healthy subjects in three different age groups (20-30, 45-55 and 70-85 years) were collected to determine a potential age effect. T lymphocytes were isolated to be exposed ex vivo for 72 hours to 45 μg/mL of FP collected in Dunkirk and chemically characterized. Overexpression of the CYP1A1, CYP1B1 and CYP2S1 genes was therefore measured after exposure of the T cells to FP. These genes code for enzymes known to be involved in the metabolic activation of organic compounds such as polycyclic aromatic hydrocarbons detected in the FP sample. T-cell profiling allowed us to suggest a mixed T-helper 1/2 profile caused by exposure to FP. With regard to the influence of age, we have observed differences in the expression of certain genes, as well as an increase in interleukin-4 and -13 concentrations in the elderly. These results showed that exposure of T lymphocytes to FP causes effects on both transcriptomic and cytokine secretion levels.

Genotoxicity and DNA damage signaling in response to complex mixtures of PAHs in biomass burning particulate matter from cashew nut roasting

Approximately 3 billion people world-wide are exposed to air pollution from biomass burning. Herein, particulate matter (PM) emitted from artisanal cashew nut roasting, an important economic activity worldwide, was investigated. This study focused on: i) chemical characterization of polycyclic aromatic hydrocarbons (PAHs) and oxygenated (oxy-) PAHs; ii) intracellular levels of reactive oxygen species (ROS); iii) genotoxic effects and time- and dose-dependent activation of DNA damage signaling, and iv) differential expression of genes involved in xenobiotic metabolism, inflammation, cell cycle arrest and DNA repair, using A549 lung cells. Among the PAHs, chrysene, benzo[a]pyrene (B[a]P), benzo[b]fluoranthene, and benz[a]anthracene showed the highest concentrations (7.8-10 ng/m³), while benzanthrone and 9,10-anthraquinone were the most abundant oxy-PAHs. Testing of PM extracts was based on B[a]P equivalent doses (B[a]P_eq). IC₅₀ values for viability were 5.7 and 3.0 nM B[a]P_eq at 24 h and 48 h, respectively. At these low doses, we observed a time- and dose-dependent increase in intracellular levels of ROS, genotoxicity (DNA strand breaks) and DNA damage signaling (phosphorylation of the protein checkpoint kinase 1 - Chk1). In comparison, effects of B[a]P alone was observed at micromolar range. To our knowledge, no previous study has demonstrated an activation of pChk1, a biomarker used to estimate the carcinogenic potency of PAHs in vitro, in lung cells exposed to cashew nut roasting extracts. Sustained induction of expression of several important stress response mediators of xenobiotic metabolism (CYP1A1, CYP1B1), ROS and pro-inflammatory response (IL-8, TNF-α, IL-2, COX2), and DNA damage response (CDKN1A and DDB2) was also identified. In conclusion, our data show high potency of cashew nut roasting PM to induce cellular stress including genotoxicity, and more potently when compared to B[a]P alone. Our study provides new data that will help elucidate the toxic effects of low-levels of PAH mixtures from air PM generated by cashew nut roasting.

Applications of Graphene and Its Derivatives in Chemical Analysis

In this review, the applications of graphene and its derivatives in the chemical analysis have been described. The properties of graphene materials which are essential for their use in chemical and biochemical analysis are characterized. The materials are used in sensors and biosensors, in electrochemistry, in chromatography and in the sample preparation techniques. Chemical and electrochemical sensors containing graphene materials are useful devices for detecting some chemical and biochemical compounds. Chromatographic columns for HPLC with graphene containing stationary phases may be used for separation of polar and nonpolar components of some specific mixtures. Graphene materials could be successfully employed during sample preparation for analysis with SPE, magnetic SPE, and SPME techniques. HighlightsThe review of the applications of graphene (G) and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), in chemical and biochemical analysis is proposed.The electron donor-acceptor and proton donor-acceptor interactions for the graphene based materials - analytes systems and their impact on the analysis results are discussed, particularly:    i) in electrochemistry,ii) in chromatography,iii) in modern sample preparation techniquesiv) in sensors of different types.The essence of the thermal stability and the nomenclature of the graphene based materials in their different applications in chemical systems of different classes was discussed (and suggested).The benefits of using SPME fibers with immobilized graphene materials have been presented in detail.

Cellular response and extracellular vesicles characterization of human macrophages exposed to fine atmospheric particulate matter

Exposure to fine atmospheric Particulate Matter (PM) is one of the major environmental causes involved in the development of inflammatory lung diseases, such as chronic obstructive pulmonary disease (COPD) or asthma. When PM is penetrating in the pulmonary system, alveolar macrophages represent the first line of defense, in particular by triggering a pro-inflammatory response, and also by their ability to recruit infiltrating macrophages from the bone marrow. The aim of this in vitro study was to evaluate the gene expression and cytokine production involved in the toxicological and inflammatory responses of infiltrating macrophages, as well as the Extracellular Vesicles (EVs) production, after their exposure to PM. The ability of these EVs to convey information related to PM exposure from exposed macrophages to pulmonary epithelial cells was also evaluated. Infiltrating macrophages respond to fine particles exposure in a conventional manner, as their exposure to PM induced the expression of Xenobiotic Metabolizing Enzymes (XMEs) such as CYP1A1 and CYP1B1, the enzymes involved in oxidative stress SOD2, NQO1 and HMOX as well as pro-inflammatory cytokines in a dose-dependent manner. Exposure to PM also induced a greater release of EVs in a dose-dependent manner. In addition, the produced EVs were able to induce a pro-inflammatory phenotype on pulmonary epithelial cells, with the induction of the release of IL6 and TNFα proinflammatory cytokines. These results suggest that infiltrating macrophages participate in the pro-inflammatory response induced by PM exposure and that EVs could be involved in this mechanism.

Seasonal Variation in the Biological Effects of PM2.5 from Greater Cairo

Greater Cairo (Egypt) is a megalopolis where the studies of the air pollution events are of extremely high relevance, for the geographical-climatological aspects, the anthropogenic emissions and the health impact. While preliminary studies on the particulate matter (PM) chemical composition in Greater Cairo have been performed, no data are yet available on the PM’s toxicity. In this work, the in vitro toxicity of the fine PM (PM_2.5) sampled in an urban area of Greater Cairo during 2017–2018 was studied. The PM_2.5 samples collected during spring, summer, autumn and winter were preliminary characterized to determine the concentrations of ionic species, elements and organic PM (Polycyclic Aromatic Hydrocarbons, PAHs). After particle extraction from filters, the cytotoxic and pro-inflammatory effects were evaluated in human lung A549 cells. The results showed that particles collected during the colder seasons mainly induced the xenobiotic metabolizing system and the consequent antioxidant and pro-inflammatory cytokine release responses. Biological events positively correlated to PAHs and metals representative of a combustion-derived pollution. PM_2.5 from the warmer seasons displayed a direct effect on cell cycle progression, suggesting possible genotoxic effects. In conclusion, a correlation between the biological effects and PM_2.5 physico-chemical properties in the area of study might be useful for planning future strategies aiming to improve air quality and lower health hazards.

Toxicological effects of ambient fine (PM2.5-0.18) and ultrafine (PM0.18) particles in healthy and diseased 3D organo-typic mucocilary-phenotype models

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.

Proinflammatory effects of dust storm and thermal inversion particulate matter (PM10) on human peripheral blood mononuclear cells (PBMCs) in vitro: a comparative approach and analysis

Particulate matter (PM) as the carcinogenic air pollutants can lead to aggravated health outcomes. Epidemiological studies demonstrated that PM can be engaged in different diseases such as cardiovascular, respiratory and cancer. The in vitro secretion of proinflammatory cytokines by human peripheral blood mononuclear cells (PBMCs) has been used to assess the effects of PM with an aerodynamic diameter < 10 μm (PM10). This study compared the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and interleukin 1-beta (IL1-β) secretions of PBMCs exposed to PM10 of dust storm and inversion. We collected PM10 samples during the spring and autumn seasons in two locations. Isolated PBMCs were exposed separately to 50, 150, and 300 μg/ml of different type of PM10 for 4 and 24 h. The mean concentrations of TNF-α for the PM of dust storm and inversion were 6305.61 ± 2421 and 6651.74 ± 2820, respectively. Also the mean concentrations of IL1-β for the PM of dust storm and inversion were 556.86 ± 162 and 656.35 ± 196, respectively. Furthermore, these values for the production of IL-6 were 12,655 ± 5661 and 16,685 ± 8069, respectively. Although no significant difference was observed between the PM of dust storm and that of inversion with regard to PBMCs, the results showed a significant increase in the proinflammatory cytokine secretion of both PMs compared with the controls. Moreover, TNF-α, IL1-β, and IL-6 secreted in cells exposed to PM10 of dust storm were about 10 times more than the controls, these values for cells exposed to PM10 of inversion were around 10, 12, and 14 times more than the controls, respectively. It can be concluded that the PM10 of both dust storm and inversion can play a significant role in proinflammatory cytokine secretion due to its harmful effect on human health. Graphical abstractThis picture shows the Proinflammatory cytokine producing potential of PM10 with two sources (dust storm and urban air pollution) in exposure with human PBMCs in vitro.

A method for particulate matter 2.5 (PM2.5) biotoxicity assay using luminescent bacterium

The ability to analyze biotoxicity of atmospheric pollution plays an important role in public health. It provides the potential to directly analyze the health information of at-risk individuals. Although air quality standards have received significant attention in many countries, the potential for better biotoxicity assessment has remained largely unexplored. Here we propose a method using one kind of luminescent bacterium Photobacterium phosphereum to detect the biotoxicity of atmospheric particulate matter ≤ 2.5 µm (PM_2.5). Combined with the results of air pollution data of the year 2013-2014, this method has been proven to have good biotoxicity detection performance, and can evaluate the severity of at least 85% of PM_2.5 related biotoxicity in Shanghai during this time period. Based on an established algorithm of this detection system, the biotoxicity of twelve PM_2.5 real samples (collected over a month) were tested and divided into different biotoxicity levels. It allows an effective evaluation of biotoxicity of PM_2.5 due to the quick and sensitive response of bioluminescence to the concentration of toxic components, which provides a valuable reference to evaluate the biotoxicity of PM_2.5. This established method can be easily applied to the analysis and evaluation of any other PM_2.5 samples assay by following the steps.

Exposure to Atmospheric Ultrafine Particles Induces Severe Lung Inflammatory Response and Tissue Remodeling in Mice

Exposure to particulate matter (PM) is leading to various respiratory health outcomes. Compared to coarse and fine particles, less is known about the effects of chronic exposure to ultrafine particles, despite their higher number and reactivity. In the present study, we performed a time-course experiment in mice to better analyze the lung impact of atmospheric ultrafine particles, with regard to the effects induced by fine particles collected on the same site. Trace element and PAH analysis demonstrated the almost similar chemical composition of both particle fractions. Mice were exposed intranasally to FF or UFP according to acute (10, 50 or 100 µg of PM) and repeated (10 µg of PM 3 times a week during 1 or 3 months) exposure protocols. More particle-laden macrophages and even greater chronic inflammation were observed in the UFP-exposed mice lungs. Histological analyses revealed that about 50% of lung tissues were damaged in mice exposed to UFP for three months versus only 35% in FF-exposed mice. These injuries were characterized by alveolar wall thickening, macrophage infiltrations, and cystic lesions. Taken together, these results strongly motivate the update of current regulations regarding ambient PM concentrations to include UFP and limit their emission.

In vitro evaluation of organic extractable matter from ambient PM2.5 using human bronchial epithelial BEAS-2B cells: Cytotoxicity, oxidative stress, pro-inflammatory response, genotoxicity, and cell cycle deregulation

A particular attention has been devoted to the type of toxicological responses induced by particulate matter (PM), since their knowledge is greatly complicated by the fact that it is a heterogeneous and often poorly described pollutant. However, despite intensive research effort, there is still a lack of knowledge about the specific chemical fraction of PM, which could be mainly responsible of its adverse health effects. We sought also to better investigate the toxicological effects of organic extractable matter (OEM) in normal human bronchial epithelial lung BEAS-2B cells. The wide variety of chemicals, including PAH and other related-chemicals, found in OEM, has been rather associated with early oxidative events, as supported by the early activation of the sensible NRF-2 signaling pathway. For the most harmful conditions, the activation of this signaling pathway could not totally counteract the ROS overproduction, thereby leading to critical oxidative damage to macromolecules (lipid peroxidation, oxidative DNA adducts). While NRF-2 is an anti-inflammatory, OEM exposure did not trigger any significant change in the secretion of inflammatory cytokines (i.e., TNFα, IL-1β, IL-6, IL-8, MCP-1, and IFNγ). According to the high concentrations of PAH and other related organic chemicals found in this OEM, CYP1A1 and 1B1 genes exhibited high transcription levels in BEAS-2B cells, thereby supporting both the activation of the critical AhR signaling pathway and the formation of highly reactive ultimate metabolites. As a consequence, genotoxic events occurred in BEAS-2B cells exposed to this OEM together with cell survival events, with possible harmful cell cycle deregulation. However, more studies are required to implement these observations and to contribute to better decipher the critical role of the organic fraction of air pollution-derived PM_2.5 in the activation of some sensitive signaling pathways closely associated with G1/S and intra-S checkpoint blockage, on the one hand, and cell survival, on the other hand.

Mass spectrometry-based metabolomics reveals the mechanism of ambient fine particulate matter and its components on energy metabolic reprogramming in BEAS-2B cells

Exposure to airborne fine particulate matter (PM_2.5) is associated with various adverse effects. However, the molecular mechanism involved in PM_2.5-elicited energy metabolic reprogramming and the toxic chemical determinants within PM_2.5 are not well elucidated. In this study, nontargeted and targeted metabolomics research were conducted to investigate the overall metabolic changes and relevant toxicological pathways caused by Taiyuan winter total PM_2.5 and its water soluble and organic soluble fractions in human lung bronchial epithelial cells (BEAS-2B). The results showed that significant metabolome alterations in BEAS-2B cells were observed after the exposure of total PM_2.5 and its organic soluble fraction. Purine metabolism, arginine and proline metabolism, glutathione (GSH) metabolism, tricarboxylic acid (TCA) cycle and glycolysis were mainly affected. Along with a significant increase of reactive oxygen species (ROS), malondialdehyde (MDA), nitric oxide (NO) and pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), obvious metabolic phenotype remodeling from oxidative phosphorylation to glycolysis was found in BEAS-2B cells treated with total PM_2.5 and its organic soluble fraction. Compared with water soluble fraction, organic soluble fraction was found to play the dominant role in PM_2.5 toxicity. Our study provided novel insights into the mechanism of PM_2.5-elicited toxicity.

Physico-chemical characterization and in vitro inflammatory and oxidative potency of atmospheric particles collected in Dakar city's (Senegal)

Exposure to atmospheric pollutants has been recognized as a major risk factor of respiratory and cardiovascular diseases. Fine particles (PM_2.5) and a coarser fraction (PM_>2.5) sampled at an urban site in Dakar (HLM), characterized by high road traffic emissions, were compared with particles sampled at a rural area, Toubab Dialaw located about 40 km from Dakar. The physicochemical characteristics of samples revealed that PMs differ for their physical (surface area) and chemical properties (in terms of CHN, metals, ions, paraffins, VOCs and PAHs) that were 65-75% higher in urban samples. Moreover the fine PMs contain higher amounts of anthropogenic related pollutants than the PM_>2.5 one. These differences are sustained by the ratios reported for the analysed PAHs which suggest as predominant primary emission sources vehicle exhausts at urban site and biomass combustion at the rural site. The inflammatory response and the oxidative damages were evaluated in BEAS-2B cells by the quantification of 4 selected inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8) and of total carbonylated proteins and the oxidative DNA adduct 8-OHdG after 8 or 24 h exposure. In accordance with the different sources and different physical and chemical properties, the inflammatory response and the oxidative damages were found higher in bronchial cells exposed to urban PMs. These data confirm the importance, also for West African countries, to evaluate the correlation between PM physico-chemical properties and potential biological impacts.

Air pollution-derived PM2.5 impairs mitochondrial function in healthy and chronic obstructive pulmonary diseased human bronchial epithelial cells

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-_kB 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.

Delineation of 3D dose-time-toxicity in human pulmonary epithelial Beas-2B cells induced by decabromodiphenyl ether (BDE209)

Due to frequent detection in environment as well as in the human body, the adverse effects of decabromodiphenyl ether (BDE209) have been extensively studied in the past few years. However, information regarding the inhalation toxicity of BDE209 to humans is currently limited. In this study, the cytotoxicity, cell damage, and inflammation markers including IL-6, IL-8, and TNF-α in the Beas-2B cell line induced by BDE209 were measured using a central composite design. Results showed that as BDE209 concentrations (5-65 μg mL^-1) and exposure time (6-30 h) were increased, cell viability sharply decreased from 99.7% to 29.7% and LDH activity increased from 0.1% to 13.1%. Furthermore, expression of IL-6, IL-8 and TNF-α transcripts were enhanced from 4.7 to 29.1 fold, 3.4-68.9 fold, and 2.8-47.0 fold, respectively, and the concentration of IL-6 and IL-8 proteins increased from 5.4 to 16.7 pg mL^-1 and 71.0-550.0 pg mL^-1, respectively. Results indicate that BDE209 exposure can inhibit cell viability, increase LDH leakage, and upregulate the transcript (mRNA) and protein levels of inflammatory markers of IL-6 and IL-8 in Beas-2B cells. Moreover, these effects were both dose- and time-dependent, and dose and time had a synergistic effect - enhancing toxicity when in combination. Cell density affected both LDH activity and IL-8 release but had little effect on cell activity and IL-6 release in the Beas-2B cells. In contrast, TNF-α protein was not detected but its mRNA expression level was upregulated. This study will provide a reference for human health risk assessment, especially for the toxic damage that BDE209 exposure can elicit in the respiratory tract.

Ecotoxicity evaluation and human risk assessment of an agricultural polluted soil

The present study aims to evaluate the nature and level of chemical pollution as well as the potential toxicity and ecotoxicity of an agricultural soil irrigated by the water of Litani River. Our findings showed that the soil was mainly contaminated by alkanes (hentriacontane, octadecane, hexadecane) and metal trace elements (nickel, vanadium, chromium, and manganese). Soil organic extracts showed high cytotoxicity against human hepatic (HepG2) and bronchial epithelial cells (Beas-2B). Soil ecotoxicity was revealed by seed germination inhibition of several plant species (wheat, clover, alfalfa, tall fescue, and ryegrass) ranging from 7 to 30% on the polluted soil compared to non-polluted one. In addition, significant decreases in telluric microbial biomasses (bacterial and fungal biomasses), quantified by phospholipid fatty acids (PLFA) analysis were observed in polluted soil compared to non-contaminated soils. The density of the arbuscular mycorrhizal fungal (AMF) spores isolated from the polluted soil was about 316 spores/100 g. Three main AMF species were identified as Funelliformis mosseae, Septoglomus constrictum, and Claroideoglomus lamellosum. Moreover, 16 indigenous plant species were inventoried with Silybum marianum L. as the dominant one. Plant biodiversity indices (Shannon, Simpson, Menhinick, and Margaleff) were lower than those found in other contaminated soils. Finally, it was found that all the present plant species on this polluted site were mycorrhized, suggesting a possible protection of these plants against encountered pollutants, and the possibility to use AMF-assisted phytoremediation to clean-up such a site.