Aeroparticles, Composition, and Lung Diseases

Effects of PM2.5 on mucus hypersecretion in airway through miR-133b-5p/EGFR/Claudin1/MUC5AC axis

OBJECTIVE

To investigate the role of the EGFR/MAPK signaling pathway in PM2.5 in promoting the MUC5AC hypersecretion in airway and exacerbating airway inflammation.

METHODS

By establishing rat model exposed to PM2.5, overexpressing miR-133b-5p and Claudin1, the content of IL-1 and TNF-α in serum were detected by ELISA, the pathology of lung tissue was observed by HE staining, p-EGFR, Claudin1, MUC5AC, p-ERK1/2, p-JNK, p-p38 in rats lung tissue were detected by immunohistochemical and WB, the expression level of miR-133b-5p in rats lung tissue were detected by qPCR.

RESULTS

After the rats were exposed to PM2.5, the content of inflammatory factors in serum increased, the inflammatory damage of lung tissues occurred, the expression of miR-133b-5p was down-regulated, and the expression of MUC5AC protein was increased. The ELISA test results showed that the expression of IL-1 and TNF-α in the model group was significantly higher than that in the control group, and the model +AG1478 treatment group was down-regulated compared with the model group, and the +miR-133b-5p agomir treatment group was significantly lower than that in the control group, the model group and the model +Claudin1 overexpression blank load group, and the model +Claudin1 overexpression group was down-regulated compared with the model group and the model +Claudin1 overexpression blank load group. The protein detection results showed that the expression of p-EGFR, MUC5AC, p-ERK1/2, p-JNK and p-p38 proteins was increased and the expression of Claudin1 protein was decreased in the model group compared with the control group. In the model + AG1478 treatment group, model + miR-133b-5p agomir treatment group and model + Claudin1 overexpression group, compared with the model group, p-EGFR, MUC5AC, p-ERK1/2, p-JNK, p-p38 protein expression was down-regulated, and Claudin1 protein expression was up-regulated.

CONCLUSIONS

PM2.5 inhibited the expression of miR-133b-5p to activate the EGFR/MAPK signal pathway, induce the hypersecretion of MUC5AC, thus aggravating PM2.5-related airway inflammation in rats.

Sampling, composition, and biological effects of Mexico City airborne particulate matter from multiple periods

Air pollution is a worldwide environmental problem with an impact on human health. Particulate matter of ten micrometers or less aerodynamic diameter (PM10) as well as its fine fraction (PM2.5) is related to multiple pulmonary diseases. The impact of air pollution in Mexico City, and importantly, particulate matter has been studied and considered as a risk factor for two decades ago. Previous studies have reported the composition of Mexico City particulate matter, as well as the biological effects induced by this material. However, material collected and used in previous studies is a limited resource, and sampling and particle recovery techniques have been improved. In this study, we describe the methods used in our laboratory for Mexico City airborne particulate matter PM10 and PM2.5 sampling, considering the years 2017, 2018 and 2019. We also analyzed the PM10 and PM2.5 samples obtained to determine their composition. Finally, we exposed lung cell line cultures to PM10 and PM2.5 to evaluate the biological effect of the material in terms of cell viability, cell death, inflammatory response, and cytogenetic alterations. Our results showed that PM10 composition includes inorganic, organic and biological compounds, while PM2.5 is a mixture of more enriched organic compounds. PM10 and PM2.5 treatment in lung cells does not significantly impact cell viability/cell death. However, PM10 and PM2.5 increase the secretion levels of IL-6. Moreover, PM10 as well as PM2.5 induce cytogenetic alterations, such as micronuclei, anaphase bridges, trinucleated cells and apoptotic cells in lung cells. Our results update the evidence of the composition and biological effects of Mexico City particulate matter and provide us a reliable basis for future approaches.

Determining the toxicological effects of indoor air pollution on both a healthy and an inflammatory-comprised model of the alveolar epithelial barrier in vitro

Exposure to indoor air pollutants (IAP) has increased recently, with people spending more time indoors (i.e. homes, offices, schools and transportation). Increased exposures of IAP on a healthy population are poorly understood, and those with allergic respiratory conditions even less so. The objective of this study, therefore, was to implement a well-characterised in vitro model of the human alveolar epithelial barrier (A549 + PMA differentiated THP-1 incubated with and without IL-13, IL-5 and IL-4) to determine the effects of a standardised indoor particulate (NIST 2583) on both a healthy lung model and one modelling a type-II (stimulated with IL-13, IL-5 and IL-4) inflammatory response (such as asthma).Using concentrations from the literature, and an environmentally appropriate exposure we investigated 232, 464 and 608ng/cm2 of NIST 2583 respectively. Membrane integrity (blue dextran), viability (trypan blue), genotoxicity (micronucleus (Mn) assay) and (pro-)/(anti-)inflammatory effects (IL-6, IL-8, IL-33, IL-10) were then assessed 24 h post exposure to both models. Models were exposed using a physiologically relevant aerosolisation method (VitroCell Cloud 12 exposure system).No changes in Mn frequency or membrane integrity in either model were noted when exposed to any of the tested concentrations of NIST 2583. A significant decrease (p < 0.05) in cell viability at the highest concentration was observed in the healthy model. Whilst cell viability in the "inflamed" model was decreased at the lower concentrations (significantly (p < 0.05) after 464ng/cm2). A significant reduction (p < 0.05) in IL-10 and a significant increase in IL-33 was seen after 24 h exposure to NIST 2583 (464, 608ng/cm2) in the "inflamed" model.Collectively, the results indicate the potential for IAP to cause the onset of a type II response as well as exacerbating pre-existing allergic conditions. Furthermore, the data imposes the importance of considering unhealthy individuals when investigating the potential health effects of IAP. It also highlights that even in a healthy population these particles have the potential to induce this type II response and initiate an immune response following exposure to IAP.

Synergistic approaches to elevate indoor air quality: A holistic examination of classroom refinement, air exchange optimization, and flooring material impact

This research endeavors to elevate indoor air quality within aging school environments by concentrating on refining interior finishing materials and windows. Renovations, encompassing window and floor remodeling in classrooms, aim to mitigate particulate matter (PM) infiltration and enhance air exchange rates. Utilizing SPS30 sensors for the analysis of 0.3-2.5 μm particles, with a focus on their implications for human health, the study evaluated air exchange rates, deposition rates, infiltration rates, and particle generation during classroom activities. Post-renovation results demonstrated a noteworthy decrease in air exchange rates, indicating an enhancement in airtightness. The investigation delves into particle generation with various flooring materials, accentuating the importance of opting for durable and low-particle-generating alternatives. Health risk assessments, considering multiple exposure routes (inhalation, dermal contact, and ingestion), revealed reduced risks post-renovation, particularly for children. To further optimize indoor air quality, the study suggests the implementation of air purification systems. Examination of PM generation during student activities showcased a substantial reduction post-renovation. This study underscores the positive influence of architectural enhancements on indoor air quality while acknowledging the necessity for holistic solutions and continuous research.

Adverse Health Effects of the Long-Term Simultaneous Exposure to Arsenic and Particulate Matter in a Murine Model

PM2.5 and arsenic are two of the most hazardous substances for humans that coexist worldwide. Independently, they might cause multiple organ damage. However, the combined effect of PM2.5 and arsenic has not been studied. Here, we used an animal model of simultaneous exposure to arsenic and PM2.5. Adult Wistar rats were exposed to PM2.5, As, or PM2.5 + As and their corresponding control groups. After 7, 14, and 28 days of exposure, the animals were euthanized and serum, lungs, kidneys, and hearts were collected. Analysis performed showed high levels of lung inflammation in all experimental groups, with an additive effect in the coexposed group. Besides, we observed cartilaginous metaplasia in the hearts of all exposed animals. The levels of creatine kinase, CK-MB, and lactate dehydrogenase increased in experimental groups. Tissue alterations might be related to oxidative stress through increased GPx and NADPH oxidase activity. The findings of this study suggest that exposure to arsenic, PM2.5, or coexposure induces high levels of oxidative stress, which might be associated with lung inflammation and heart damage. These findings highlight the importance of reducing exposure to these pollutants to protect human health.

The stress-responsive cytotoxic effect of diesel exhaust particles on lymphatic endothelial cells

Diesel exhaust particles (DEPs) are very small (typically < 0.2 μm) fragments that have become major air pollutants. DEPs are comprised of a carbonaceous core surrounded by organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs. Inhaled DEPs reach the deepest sites in the respiratory system where they could induce respiratory/cardiovascular dysfunction. Additionally, a previous study has revealed that a portion of inhaled DEPs often activate immune cells and subsequently induce somatic inflammation. Moreover, DEPs are known to localize in lymph nodes. Therefore, in this study we explored the effect of DEPs on the lymphatic endothelial cells (LECs) that are a constituent of the walls of lymph nodes. DEP exposure induced cell death in a reactive oxygen species (ROS)-dependent manner. Following exposure to DEPs, next-generation sequence (NGS) analysis identified an upregulation of the integrated stress response (ISR) pathway and cell death cascades. Both the soluble and insoluble components of DEPs generated intracellular ROS. Three-dimensional Raman imaging revealed that DEPs are taken up by LECs, which suggests internalized DEP cores produce ROS, as well as soluble DEP components. However, significant cell death pathways such as apoptosis, necroptosis, ferroptosis, pyroptosis, and parthanatos seem unlikely to be involved in DEP-induced cell death in LECs. This study clarifies how DEPs invading the body might affect the lymphatic system through the induction of cell death in LECs.

Chronic exposure to PM10 induces anxiety-like behavior via exacerbating hippocampal oxidative stress

As one of the most environmental concerns, inhaled particulate matter (PM10) causes numerous health problems. However, the associations between anxiety behavior and toxicity caused by PM10 have rarely been reported so far. To investigate the changes of behavior after PM10 exposure and to identify the potential mechanisms of toxicity, PM10 samples (with doses of 15 mg/kg and 30 mg/kg) were intratracheally instilled into rats to simulate inhalation of polluted air by the lungs. After instillation for eight weeks, anxiety-like behavior was evaluated, levels of oxidative stress and morphological changes of hippocampus were measured. The behavioral results indicated that PM10 exposure induced obvious anxiety-like behavior in the open field and elevated plus maze tests. Both PM10 concentrations tested could increase whole blood viscosity and trigger hippocampal neuronal damage and oxidative stress by increasing superoxide dismutase (SOD) activities and malondialdehyde levels, and decreasing the expressions of antioxidant-related proteins (e.g., nuclear factor erythroid 2-related factor 2 (Nrf2), SOD1 and heme oxygenase 1). Furthermore, through collecting and analyzing questionnaires, the data showed that the participants experienced obvious anxiety-related emotions and negative somatic responses under heavily polluted environments, especially PM10 being the main pollutant. These results show that PM10 exposure induces anxiety-like behavior, which may be related to suppressing the Nrf2/Keap1-SOD1 pathway.

Effective-components combination alleviates PM2.5-induced inflammation by evoking macrophage autophagy in COPD

ETHNOPHARMACOLOGICAL RELEVANCE

Bufei Yishen formula (BYF) is clinically used to treat chronic obstructive pulmonary disease (COPD). Effective-component compatibility (ECC) is a combination of five active components derived from BYF, which has an equal effect on COPD to BYF. Our previous study has also demonstrated that ECC can protect COPD rats against PM2.5 exposure. However, the precise mechanisms remain to be elucidated.

AIM OF THE STUDY

To explore the mechanism underlying the anti-inflammatory effects of ECC-BYF against PM2.5-accelerated COPD.

MATERIALS AND METHODS

MH-S macrophages were stimulated by PM2.5 suspension to establish an in vitro model. Western blotting and immunofluorescent staining were used to measure the protein levels of autophagy markers. ELISA and quantitative PCR were used to detect the levels of inflammatory cytokines. In vivo, an established PM2.5-accelerated COPD rat model was used to determine the protective effect of ECC-BYF. Lung function, pathology, autophagy, and inflammatory mediators were detected.

RESULTS

Firstly, we observed a significantly increased number of macrophages in the lungs upon PM2.5 exposure. Then, decreased autophagy flux while elevated inflammation was detected in PM2.5-exposed rats and MH-S cells. In MH-S cells, ECC-BYF significantly suppressed the PM2.5-increased inflammatory cytokines production, which was accompanied by the enhancement of autophagy flux. An autophagy inhibitor counteracted the anti-inflammatory effect elicited by ECC-BYF. In addition, ECC-BYF stimulated Foxo3 nuclear translocation and upregulated Foxo3 expression, whereas Foxo3 knockdown abrogated the inhibitory effect of ECC-BYF on inflammation. In PM2.5-accelerated COPD rats, ECC-BYF also attenuated the autophagy disruption and increased Foxo3 in the lungs, finally resulting in a suppression of pulmonary inflammation and an enhancement of lung function.

CONCLUSION

ECC-BYF can ameliorate PM2.5-aggravated inflammation in COPD, which might be associated with the enhancement of autophagy flux in alveolar macrophages through the activation of Foxo3 signals.

Air pollution, lung function and mortality: survival and mediation analyses in UK Biobank

Background

Air pollution is associated with lower lung function, and both are associated with premature mortality and cardiovascular disease (CVD). Evidence remains scarce on the potential mediating effect of impaired lung function on the association between air pollution and mortality or CVD.

Methods

We used data from UK Biobank (n∼200 000 individuals) with 8-year follow-up to mortality and incident CVD. Exposures to particulate matter <10 µm (PM10), particulate matter <2.5 µm (PM2.5) and nitrogen dioxide (NO2) were assessed by land-use regression modelling. Lung function (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and the FEV1/FVC ratio) was measured between 2006 and 2010 and transformed to Global Lung Function Initiative (GLI) z-scores. Adjusted Cox proportional hazards and causal proportional hazards mediation analysis models were fitted, stratified by smoking status.

Results

Lower FEV1 and FVC were associated with all-cause and CVD mortality, and incident CVD, with larger estimates in ever- than never-smokers (all-cause mortality hazard ratio per FEV1 GLI z-score decrease 1.29 (95% CI 1.24-1.34) for ever-smokers and 1.16 (95% CI 1.12-1.21) for never-smokers). Long-term exposure to PM2.5 or NO2 was associated with incident CVD, with similar effect sizes for ever- and never-smokers. Mediated proportions of the air pollution-all-cause mortality estimates driven by FEV1 were 18% (95% CI 2-33%) for PM2.5 and 27% (95% CI 3-51%) for NO2. Corresponding mediated proportions for incident CVD were 9% (95% CI 4-13%) for PM2.5 and 16% (95% CI 6-25%) for NO2.

Conclusions

Lung function may mediate a modest proportion of associations between air pollution and mortality and CVD outcomes. Results likely reflect the extent of either shared mechanisms or direct effects relating to lower lung function caused by air pollution.

Disruption of phosphofructokinase activity and aerobic glycolysis in human bronchial epithelial cells by atmospheric ultrafine particulate matter

Exposure to ambient ultrafine particulate matter (UPM) causes respiratory disorders; however, the underlying molecular mechanisms remain unclear. In this study, we synthesized simulated UPM (sUPM) with controlled physicochemical properties using the spark-discharge method. Subsequently, we investigated the biological effects of sUPM using BEAS-2B human bronchial epithelial cells (HBECs) and a mouse intratracheal instillation model. High throughput RNA-sequencing and bioinformatics analyses revealed that dysregulation of the glycolytic metabolism is involved in the inhibited proliferation and survival of HBECs by sUPM treatment. Furthermore, signaling pathway and enzymatic analyses showed that the treatment of BEAS-2B cells with sUPM induces the inactivation of extracellular signal-regulated kinase (ERK) and protein kinase B (PKB, also known as AKT), resulting in the downregulation of phosphofructokinase 2 (PFK2) S483 phosphorylation, PFK enzyme activity, and aerobic glycolysis in HBECs in an oxidative stress-independent manner. Additionally, intratracheal instillation of sUPM reduced the phosphorylation of ERK, AKT, and PFK2, decreased proliferation, and increased the apoptosis of bronchial epithelial cells in mice. The findings of this study imply that UPM induces pulmonary toxicity by disrupting aerobic glycolytic metabolism in lung epithelial cells, which can provide novel insights into the toxicity mechanisms of UPM and strategies to prevent their toxic effects.

Antibiotic resistance genes associated with size-segregated bioaerosols from wastewater treatment plants: A review

The antibiotic-resistant pollution in size-segregated bioaerosols from wastewater treatment plants (WWTPs) is of increasing concern due to its public health risks, but an elaborate review is still lacking. This work overviewed the profile, mobility, pathogenic hosts, source, and risks of antibiotic resistance genes (ARGs) in size-segregated bioaerosols from WWTPs. The dominant ARG type in size-segregated bioaerosols from WWTPs was multidrug resistance genes. Treatment units that equipped with mechanical facilities and aeration devices, such as grilles, grit chambers, biochemical reaction tanks, and sludge treatment units, were the primary sources of bioaerosol antibiotic resistome in WWTPs. Higher enrichment of antibiotic resistome in particulate matter with an aerodynamic diameter of <2.5 μm, was found along the upwind-downwind-WWTPs gradient. Only a small portion of ARGs in inhalable bioaerosols from WWTPs were flanked by mobile genetic elements. The pathogens with multiple drug resistance had been found in size-segregated bioaerosols from WWTPs. Different ARGs or antibiotic resistant bacteria have different aerosolization potential associated with bioaerosols from various treatment processes. The validation of pathogenic antibiotic resistance bacteria, deeper investigation of ARG mobility, emission mechanism of antibiotic resistome, and development of treatment technologies, should be systematically considered in future.

The association between ambient air pollution exposure and connective tissue sarcoma risk: a nested case-control study using a nationwide population-based database

A nationwide population-based database was utilized in a nested case-control study to explore the association between ambient air pollution exposure and the likelihood of developing connective tissue sarcoma. The study examined 280 cases of connective tissue sarcoma diagnosed between 2000 and 2012. A random sample of 1120 control subjects was selected from a subpopulation of claim records without a connective tissue sarcoma diagnosis in a 1:4 ratio. The control subjects were selected based on similar characteristics as the connective tissue sarcoma patients, including gender, birth year, and the year of diagnosis of the case group with medical records. Risk factors for connective tissue sarcoma were collected for analysis. Our data on exposure to air pollutants was collected from Taiwan's Air Quality Monitoring Network, which has been gathering air quality data from a growing network of sampling stations (now 76) throughout the country since 1997. It was discovered that the risk of connective tissue sarcoma was significantly increased by the Charlson comorbidity index (CCI), elevated levels of specific air pollution indices (e.g., total hydrocarbons (THC), fine particulate matter (PM2.5), and O3_8 (the annual mean of the daily maximum 8-h average concentration of O3), the High Pollutant Standards Index (hPSI) (the percentage of days in a given year in Taiwan where the PSI exceeds 100), and an insurable monthly wage over US$1100. Further investigation is needed to explore the involvement of these air pollutants in the formation of connective tissue sarcoma.

Epigenetic mechanisms of particulate matter exposure: air pollution and hazards on human health

Environmental pollution nowadays has not only a direct correlation with human health changes but a direct social impact. Epidemiological studies have evidenced the increased damage to human health on a daily basis because of damage to the ecological niche. Rapid urban growth and industrialized societies importantly compromise air quality, which can be assessed by a notable accumulation of air pollutants in both the gas and the particle phases. Of them, particulate matter (PM) represents a highly complex mixture of organic and inorganic compounds of the most variable size, composition, and origin. PM being one of the most complex environmental pollutants, its accumulation also varies in a temporal and spatial manner, which challenges current analytical techniques used to investigate PM interactions. Nevertheless, the characterization of the chemical composition of PM is a reliable indicator of the composition of the atmosphere, the quality of breathed air in urbanized societies, industrial zones and consequently gives support for pertinent measures to avoid serious health damage. Epigenomic damage is one of the most promising biological mechanisms of air pollution-derived carcinogenesis. Therefore, this review aims to highlight the implication of PM exposure in diverse molecular mechanisms driving human diseases by altered epigenetic regulation. The presented findings in the context of pan-organic cancer, fibrosis, neurodegeneration and metabolic diseases may provide valuable insights into the toxicity effects of PM components at the epigenomic level and may serve as biomarkers of early detection for novel targeted therapies.

Distribution characteristics and potential risks of bioaerosols during scattered farming

In most economically underdeveloped areas, scattered farming and human‒livestock cohabitation are common. However, production of bioaerosols and their potential harm in these areas have not been previously researched. In this study, bioaerosol characteristics were analyzed in scattered farming areas in rural Northwest China. The highest bacteria, fungi, and Enterobacteria concentrations were 125609 ± 467 CFU/m³, 25175 ± 10305 CFU/m³, and 4167 ± 592 CFU/m³, respectively. Most bioaerosols had particle sizes >3.3 μm. A total of 71 bacterial genera and 16 fungal genera of potential pathogens were identified, including zoonotic potential pathogenic genera. Moreover, our findings showed that the scattered farming pattern of human‒animal cohabitation can affect the indoor air environment in the surrounding area, leading to chronic respiratory diseases in the occupants. Therefore, relevant government departments and farmers should enhance their awareness of bioaerosol risks and consider measures that may be taken to reduce them.

Computational Tools for Handling Molecular Clusters: Configurational Sampling, Storage, Analysis, and Machine Learning

Computational modeling of atmospheric molecular clusters requires a comprehensive understanding of their complex configurational spaces, interaction patterns, stabilities against fragmentation, and even dynamic behaviors. To address these needs, we introduce the Jammy Key framework, a collection of automated scripts that facilitate and streamline molecular cluster modeling workflows. Jammy Key handles file manipulations between varieties of integrated third-party programs. The framework is divided into three main functionalities: (1) Jammy Key for configurational sampling (JKCS) to perform systematic configurational sampling of molecular clusters, (2) Jammy Key for quantum chemistry (JKQC) to analyze commonly used quantum chemistry output files and facilitate database construction, handling, and analysis, and (3) Jammy Key for machine learning (JKML) to manage machine learning methods in optimizing molecular cluster modeling. This automation and machine learning utilization significantly reduces manual labor, greatly speeds up the search for molecular cluster configurations, and thus increases the number of systems that can be studied. Following the example of the Atmospheric Cluster Database (ACDB) of Elm (ACS Omega, 4, 10965-10984, 2019), the molecular clusters modeled in our group using the Jammy Key framework have been stored in an improved online GitHub repository named ACDB 2.0. In this work, we present the Jammy Key package alongside its assorted applications, which underline its versatility. Using several illustrative examples, we discuss how to choose appropriate combinations of methodologies for treating particular cluster types, including reactive, multicomponent, charged, or radical clusters, as well as clusters containing flexible or multiconformer monomers or heavy atoms. Finally, we present a detailed example of using the tools for atmospheric acid-base clusters.

Redox and inflammatory mechanisms linking air pollution particulate matter with cardiometabolic derangements

Air pollution is the largest environmental risk factor for disease and premature death. Among the different components that are present in polluted air, fine particulate matter below 2.5 μm in diameter (PM2.5) has been identified as the main hazardous constituent. PM2.5 mainly arises from fossil fuel combustion during power generation, industrial processes, and transportation. Exposure to PM2.5 correlates with enhanced mortality risk from cardiovascular diseases (CVD), such as myocardial infarction and stroke. Over the last decade, it has been increasingly suggested that PM2.5 affects CVD already at the stage of risk factor development. Among the multiple biological mechanisms that have been described, the interplay between oxidative stress and inflammation has been consistently highlighted as one of the main drivers of pulmonary, systemic, and cardiovascular effects of PM2.5 exposure. In this context, PM2.5 uptake by tissue-resident immune cells in the lung promotes oxidative and inflammatory mediators release that alter tissue homeostasis at remote locations. This pathway is central for PM2.5 pathogenesis and might account for the accelerated development of risk factors for CVD, including obesity and diabetes. However, transmission and end-organ mechanisms that explain PM2.5-induced impaired function in metabolic active organs are not completely understood. In this review, the main features of PM2.5 physicochemical characteristics related to PM2.5 ability to induce oxidative stress and inflammation will be presented. Hallmark and recent epidemiological and interventional studies will be summarized and discussed in the context of current air quality guidelines and legislation, knowledge gaps, and inequities. Lastly, mechanistic studies at the intersection between redox metabolism, inflammation, and function will be discussed, with focus on heart and adipose tissue alterations. By offering an integrated analysis of PM2.5-induced effects on cardiometabolic derangements, this review aims to contribute to a better understanding of the pathogenesis and potential interventions of air pollution-related CVD.

Particle-size stratification of airborne antibiotic resistant genes, mobile genetic elements, and bacterial pathogens within layer and broiler farms in Beijing, China

The particle-size distribution of antimicrobial resistant (AMR) elements is crucial in evaluating their environmental behavior and health risks, and exposure to the fecal microbiome via particle mass (PM) is an important route of transmission of AMR from livestock to humans. However, few studies have explored the association between air and fecal AMR in farm environments from the perspective of particle-size stratification. We collected feces and PMs of different sizes from layer and broiler farms, quantified antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and human pathogenic bacteria (HPB) using Droplet digital PCR (ddPCR), and analyzed the bacterial communities based on 16S rRNA sequencing. The particle-size distributions of 16S rRNA and AMR elements were similar and generally increased with larger particle sizes in chicken farms. In broiler farms, we observed a bimodal distribution with two peaks at 5.8-9.0 μm and 3.3-4.7 μm. The dominant airborne bacterial phyla were Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. The dominant phyla in the feces were the same as those in the air, but the order of relative abundance varied. The particle-size distributions of specific bacterial genera differed between the animal-farm types. Overall, the degree of association between feces and different particulates increased with increasing particle size. The microbial communities in the coarse particles were similar to those in fecal samples. Escherichia coli, Staphylococcus spp., Campylobacter spp., and sul 2 (sulfonamide ARGs) tended to attach to small particles. We highlight the particle size-specific relationship between fecal and air microbes involving ARGs, MGEs, and HPB and provide valuable information for comprehensively assessing the transmission of fecal microorganisms through the airpath and its environmental and occupational health risks.

Complex urban atmosphere alters alveolar stem cells niche properties and drives lung fibrosis

There is growing evidence suggesting that urban pollution has adverse effects on lung health. However, how urban pollution affects alveolar mesenchymal and epithelial stem cell niches remains unknown. This study aimed to determine how complex representative urban atmospheres alter alveolar stem cell niche properties. Mice were placed in an innovative chamber realistically simulating the atmosphere of a megalopolis, or "clean air," for 7 days. Lungs were collected, and fibroblasts and epithelial cells (EpCAM+) were isolated. Proliferative capacities of fibroblasts were tested by population doubling levels (PDL), and microarray analyses were performed. Fibroblasts and EpCAM+ cells from exposed, nonexposed, or naive mice were cocultured in organoid assays to assess the stem cell properties. Collagen deposition (Sirius red), lipofibroblasts (ADRP, COL1A1), myofibroblasts (αSMA), alveolar type 2 cells (AT2, SFTPC+), and alveolar differentiation intermediate cell [ADI, keratin-8-positive (KRT8+)/claudin-4-positive (CLDN4+)] markers were quantified in the lungs. Fibroblasts obtained from mice exposed to urban atmosphere had lower PDL and survival and produced fewer and smaller organoids. Microarray analysis showed a decrease of adipogenesis and an increase of genes associated with fibrosis, suggesting a lipofibroblast to myofibroblast transition. Collagen deposition and myofibroblast number increased in the lungs of urban atmosphere-exposed mice. AT2 number was reduced and associated with an increase in ADI cells KRT8+/CLDN4+. Furthermore, EpCAM+ cells from exposed mice also produced fewer and smaller organoids. In conclusion, urban atmosphere alters alveolar mesenchymal stem cell niche properties by inducing a lipofibroblast to myofibroblast shift. It also results in alveolar epithelial dysfunction and a fibrotic-like phenotype.NEW & NOTEWORTHY Urban pollution is known to have major adverse effects on lung health. To assess the effect of pollution on alveolar regeneration, we exposed adult mice to a simulated high-pollution urban atmosphere, using an innovative CESAM simulation chamber (Multiphase Atmospheric Experimental Simulation Chamber, https://cesam.cnrs.fr/). We demonstrated that urban atmosphere alters alveolar mesenchymal stem cell niche properties by inducing a lipofibroblast to myofibroblast shift and induces alveolar epithelial dysfunction.

Effect of forceful suction and air disinfection machines on aerosol removal

BACKGROUNDS

Dental procedures involving drilling and grinding can produce a significant amount of suspended aerosol particles (PM) and bioaerosols. This study aims to analyze the size and concentration of aerosol particles generated during drilling and to investigate the effectiveness of two air exchange systems, namely forceful suction (FS) and air disinfection machines (DM), in removing PM.

METHODS

For this study, 100 extracted permanent teeth were collected and divided into three groups: without suction (n = 50), suction with forceful suction (n = 25), and suction with air disinfection machines (n = 25). The removal rate of suspended aerosol particles was analyzed using particle counters and air data multimeter.

RESULTS

When drilling and grinding were performed without vacuum, 0.75% of the aerosol particles generated were PM2.5-10, 78.25% of total suspended aerosol particles (TSP) were PM2.5, and 98.68% of TSP were PM1. The nanoanalyzer measurements revealed that the aerodynamic diameter of most aerosol particles was below 60 nm, with an average particle diameter of 52.61 nm and an average concentration of 2.6*1011 ultrafine aerosol particles. The air change per hour (ACH) was significantly lower in the air disinfection machines group compared to the forceful suction group. Additionally, the number of aerosol particles and mass concentration was significantly lower in the air disinfection machines group compared to the forceful suction group in terms of PM2.5 levels. However, the forceful suction group also reduced the mass concentration in PM10 level than the air disinfection machines group.

CONCLUSION

In conclusion, the air exchange system can reduce the aerosol particles generated during drilling and grinding. Comparing the two air exchange systems, it was found that the air disinfection machines group reduces the number of aerosol particles and mass concentration in PM2.5 levels, while the forceful suction group reduces the mass concentration in PM10 level.

Surgical smoke: A hidden killer in the operating room

Surgical smoke is a byproduct of aerosols containing several components produced by energy equipment. The characteristics of surgical smoke components produced by different types of tissues or using different kinds of energy devices vary. For example, the average diameter of smoke particles produced by electrocautery is smaller, and the possibility of viable cells and pathogens in surgical smoke produced by an ultrasonic knife is higher. According to the characteristics of its composition, surgical smoke may be an important risk factor affecting the health and safety of operating room staff and patients. The use of surgical masks, suction devices and portable smoke evacuation systems can reduce this risk to some extent. However, most operating room staff members do not implement corresponding measures to protect themselves. In this paper, the characteristics of surgical smoke and the research progress in protective measures are briefly reviewed.

linc01515 regulates PM2.5-induced oxidative stress via targeting NRF2 in airway epithelial cells

Dysregulation of long non-coding RNAs (lncRNAs) is involved in the adverse effects caused by fine particulate matter (PM2.5). However, the molecular mechanism is not fully clarified. In this study, we performed lncRNA sequencing on PM2.5-treated human bronchial epithelial (HBE) cells to identify vital lncRNAs, and verified the differential expression of the lncRNAs by RT-qPCR in HBE and human normal lung epithelial (BEAS-2B) cells. A total of 657 and 652 lncRNAs were dysregulated after exposure to 125 and 250 μg/mL of PM2.5, respectively. Of these, lncRNA linc01515 was upregulated in HBE and BEAS-2B cells with PM2.5 treatment. Subcellular localization experiments showed that linc01515 was mostly localized in the nucleus. Functionally, we downregulated the expression of linc01515 in HBE and BEAS-2B cells before PM2.5 treatment, which can decrease malonydialdehyde (MDA) and reactive oxygen species (ROS) levels, and improve superoxide dismutase (SOD) activity. Correspondingly, linc01515 overexpression enhanced PM2.5-induced oxidative injury in airway epithelial cells. Mechanistically, N6-methyladenosine RNA binding protein immunoprecipitation (MeRIP) assay showed that the enrichment level of m6A on linc01515 was increased after PM2.5 treatment, and the m6A modification level and expression of linc01515 was decreased in the HBE cells with 3-deazaadenosine (DAA) treatment or knockdown of METTL3 to inhibit the RNA methylation level. Western blot found that NRF2, a vital transcription factor, was enhanced remarkably in linc01515-silenced cells and decreased in linc01515-overexpressed cells. Furthermore, inhibition of NRF2 activity significantly rescued effect of downregulated linc01515 expression on PM2.5-induced cytotoxicity. In addition, we observed the similar effect when downregulating linc01515 and NRF2 expression in HBE and BEAS-2B cells before PM2.5 treatment. Taken together, our findings demonstrated that PM2.5 treatment may upregulate the expression of linc01515 by enhancing its m6A modification, and then regulate NRF2 to induce oxidative damage of airway epithelial cells.

Application of machine learning to predict hospital visits for respiratory diseases using meteorological and air pollution factors in Linyi, China

Urbanization and industrial development have resulted in increased air pollution, which is concerning for public health. This study evaluates the effect of meteorological factors and air pollution on hospital visits for respiratory diseases (pneumonia, acute upper respiratory infections, and chronic lower respiratory diseases). The test dataset comprises meteorological parameters, air pollutant concentrations, and outpatient hospital visits for respiratory diseases in Linyi, China, from January 1, 2016 to August 20, 2022. We use support vector regression (SVR) to build models that enable analysis of the effect of meteorological factors and air pollutants on the number of outpatient visits for respiratory diseases. Spearman correlation analysis and SVR model results indicate that NO2, PM2.5, and PM10 are correlated with the occurrence of respiratory diseases, with the strongest correlation relating to pneumonia. An increase in the daily average temperature and daily relative humidity decreases the number of patients with pneumonia and chronic lower respiratory diseases but increases the number of patients with acute upper respiratory infections. The SVR modeling has the potential to predict the number of respiratory-related hospital visits. This work demonstrates that machine learning can be combined with meteorological and air pollution data for disease prediction, providing a useful tool whereby policymakers can take preventive measures.

Protective effects of inhaled antioxidants against air pollution-induced pathological responses

As the public health burden of air pollution continues to increase, new strategies to mitigate harmful health effects are needed. Dietary antioxidants have previously been explored to protect against air pollution-induced lung injury producing inconclusive results. Inhaled (pulmonary or nasal) administration of antioxidants presents a more promising approach as it could directly increase antioxidant levels in the airway surface liquid (ASL), providing protection against oxidative damage from air pollution. Several antioxidants have been shown to exhibit antioxidant, anti-inflammatory, and anti-microbial properties in in vitro and in vivo models of air pollution exposure; however, little work has been done to translate these basic research findings into practice. This narrative review summarizes these findings and data from human studies using inhaled antioxidants in response to air pollution, which have produced positive results, indicating further investigation is warranted. In addition to human studies, cell and murine studies should be conducted using more relevant models of exposure such as air-liquid interface (ALI) cultures of primary cells and non-aqueous apical delivery of antioxidants and pollutants. Inhalation of antioxidants shows promise as a protective intervention to prevent air pollution-induced lung injury and exacerbation of existing lung disease.

Genomic Characterization Revealed PM2.5-Associated Mutational Signatures in Lung Cancer Including Activation of APOBEC3B

Fine particulate matter (PM_2.5) exposure causes DNA mutations and abnormal gene expression leading to lung cancer, but the detailed mechanisms remain unknown. Here, analysis of genomic and transcriptomic changes upon a PM_2.5 exposure-induced human bronchial epithelial cell-based malignant transformed cell model in vitro showed that PM_2.5 exposure led to APOBEC mutational signatures and transcriptional activation of APOBEC3B along with other potential oncogenes. Moreover, by analyzing mutational profiles of 1117 non-small cell lung cancers (NSCLCs) from patients across four different geographic regions, we observed a significantly higher prevalence of APOBEC mutational signatures in non-smoking NSCLCs than smoking in the Chinese cohorts, but this difference was not observed in TCGA or Singapore cohorts. We further validated this association by showing that the PM_2.5 exposure-induced transcriptional pattern was significantly enriched in Chinese NSCLC patients compared with other geographic regions. Finally, our results showed that PM_2.5 exposure activated the DNA damage repair pathway. Overall, here we report a previously uncharacterized association between PM_2.5 and APOBEC activation, revealing a potential molecular mechanism of PM_2.5 exposure and lung cancer.

Dispersion characteristics of bioaerosols during treatment of rural solid waste in northwest China

In rural China, the release of bioaerosols containing pathogens from solid waste dumps poses a potential health risk to the local population. Here, we sampled bioaerosols from rural solid waste-treatment in four provinces of northwest China to investigate their emission and dispersion characteristics in order to provide a scientific basis for control and risk reduction of bioaerosols released from rural sanitation facilities. The airborne bioaerosol concentrations and particle size distributions were calculated using an Anderson six-stage airborne microbial sampler and counting with its internal Petri dish culture. High-throughput sequencing was used to characterize the microbial composition at different sampling sites and to explore possible influencing factors, while the health risk associated with exposure was estimated based on average daily dose-rate. The highest concentration point values of bacteria and fungi in bioaerosols near the solid waste were 63,617 ± 15,007 and 8044 ± 893 CFU/m³, respectively. Furthermore, the highest concentration point values of Enterobacteriaceae was 502 ± 35 CFU/m³. Most bioaerosols were coarse particles larger than 3.3 μm. Potentially pathogenic genera of winter-indicator species detected in the air were primarily Delftia, Rhodococcus and Aspergillus. The composition of solid waste and environmental conditions are important factors in determining the characteristics of bioaerosols. Local residents are exposed to bioaerosols mainly through inhalation. Children are at a particularly high risk of exposure through both inhalation and skin contact. The results of this study show that bioaerosols in the vicinity of rural solid waste dumps pose a health risk to the surrounding population. More suitable risk assessment criteria for rural areas should be established, and corresponding control and protection measures should be taken from three aspects: generation source and transmission pathway, as well as the recipient.

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.

NAA10 Hypomethylation is associated with particulate matter exposure and worse prognosis for patients with non-small cell lung cancer

Airborne particulate matter (PM) is a major health hazard worldwide and is a key factor in lung cancer, which remains the most common type of malignancy and the leading cause of cancer-related deaths. DNA methylation is a critical mechanism underlying the detrimental effects of PM, however, the molecular link between PM exposure and lung cancer remains to be elucidated. N-α-acetyltransferase 10 (NAA10) is involved in the cell cycle, migration, apoptosis, differentiation, and proliferation. In order to investigate the role of NAA10 in PM-induced pathogenesis processes leading to lung cancer, we determined the expression and methylation of NAA10 in normal human bronchial epithelial (NHBE) cells treated with PM10, PM10-polycyclic aromatic hydrocarbons (PAH), and PM2.5 and evaluated the prognostic value of the NAA10 methylation status in lung cancer patients. Exposure to all PM types significantly increased the expression of NAA10 mRNA and decreased the methylation of the NAA10 promoter in NHBE cells compared with the mock-treated control. NAA10 hypomethylation was observed in 9.3% (13/140) of lung cancer tissue samples and correlated with NAA10 transcriptional upregulation. Univariate and multivariate analyses revealed that NAA10 hypomethylation was associated with decreased survival of patients with lung cancer. Therefore, these results suggest that PM-induced hypomethylation of the NAA10 may play an important role in the pathogenesis of lung cancer and may be used as a potential prognostic biomarker for lung cancer progression. Further studies with large numbers of patients are warranted to confirm our findings.

Breathing Fresh Air in the City: Implementing Avenue Trees as a Sustainable Solution to Reduce Particulate Pollution in Urban Agglomerations

The issue of air pollution from particulate matter (PM) is getting worse as more and more people move into urban areas around the globe. Due to the complexity and diversity of pollution sources, it has long been hard to rely on source control techniques to manage this issue. Due to the fact that urban trees may provide a variety of ecosystem services, there is an urgent need to investigate alternative strategies for dramatically improving air quality. PM has always been a significant concern due to its adverse effects on humans and the entire ecosystem. The severity of this issue has risen in the current global environmental context. Numerous studies on respiratory and other human disorders have revealed a statistical relationship between human exposure to outdoor levels of particles or dust and harmful health effects. These risks are undeniably close to industrial areas where these airborne, inhalable particles are produced. The combined and individual effects of the particle and gaseous contaminants on plants' general physiology can be detrimental. According to research, plant leaves, the primary receptors of PM pollution, can function as biological filters to remove significant amounts of particles from the atmosphere of urban areas. This study showed that vegetation could provide a promising green infrastructure (GI) for better air quality through the canopy and leaf-level processes, going beyond its traditional role as a passive target and sink for air pollutants. Opportunities exist for urban GI as a natural remedy for urban pollution caused by PMs.

N6-methyladenosine mediates Nrf2 protein expression involved in PM2.5-induced pulmonary fibrosis

It has been reported that particulate matter with an aerodynamic diameter of <2.5 µm (PM2.5) could induce epithelial-mesenchymal transition (EMT)- and extracellular matrix (ECM)-related pulmonary fibrosis (PF). The transcription factor Nrf2 alleviated PM2.5-induced PF by antagonizing oxidative stress. The N⁶-methyladenosine (m⁶A) modification plays a significant role in the stress response. However, the effect of m⁶A modification on the mechanisms of Nrf2-mediated defense against PM2.5-induced PF remained unknown. Here, we explored the role and the underlying molecular mechanisms of m⁶A methylation of Nrf2 mRNA in PM2.5-induced PF. We established filtered air (FA), unfiltered air (UA), and concentrated PM2.5 air (CA) group mice model and 0, 50, and 100 μg/mL PM2.5-treated 16HBE cell models. The extent of lung fibrosis in mice and fibrosis indicators were detected by histopathological analysis, immunohistochemical staining and western blotting. The molecular mechanism of m⁶A-modified Nrf2 was demonstrated by m⁶A-methylated RNA immunoprecipitation (MeRIP), RNA immunoprecipitation (RIP), qRT-PCR and T3 ligase-based PCR. Our data showed that PM2.5 exposure for 16 weeks could induce pulmonary fibrosis and activate Nrf2 signaling pathway. m⁶A methyltransferase METTL3 was upregulated after PM2.5 treatment in vivo and in vitro. Moreover, METTL3 mediated m⁶A modification of Nrf2 mRNA and promoted Nrf2 translation in mice and 16HBE cells after PM2.5 exposure. Mechanistically, three m⁶A-modified sites (1317, 1376 and 935; numbered relative to the first nucleotide of 3'UTR) of Nrf2 mRNA were identified in PM2.5-treatment 16HBE cells. Furthermore, the m⁶A binding proteins YTHDF1/IGF2BP1 promoted Nrf2 translation by binding to m⁶A residues of Nrf2 mRNA. Our results revealed the mechanism of m⁶A mediated Nrf2 signaling pathway against oxidative stress, which affected the development of PM2.5-induced PF.

Health risk assessment of PM2.5 and PM2.5-bound trace elements in Pretoria, South Africa

Exposure to outdoor air pollutants poses a risk for both non-carcinogenic and carcinogenic respiratory disease outcomes. A standardized health risk assessment (US EPA) utilizes air quality data, body mass and breathing rates to determine potential risk. This health risk assessment study assesses the hazard quotient (HQ) for total PM_2.5 and trace elemental constituents (Br, Cl, K, Ni, S, Si, Ti and U) exposure in Pretoria, South Africa. The World Health Organization (WHO) air quality guideline (5 µg m^-3) and the yearly South African National Ambient Air Quality Standard (NAAQS) (20 µg m^-3) were the references dosages for total PM_2.5. A total of 350 days was sampled in Pretoria, South Africa. The mean total PM_2.5 concentration during the 34-month study period was 23.2 µg m^-3 (0.7-139 µg m^-3). The HQ for total PM_2.5 was 1.17, 3.47 and 3.78 for adults, children and infants. Non-carcinogenic risks for trace elements K, Cl, S and Si were above 1 for adults. Seasonally, Si was the highest during autumn for adults (1.9) and during spring for S (5.5). The HQ values for K and Cl were highest during winter. The exposure to Ni posed a risk for cancer throughout the year and for As during winters.

Atmospheric Sulfuric Acid-Multi-Base New Particle Formation Revealed through Quantum Chemistry Enhanced by Machine Learning

The formation of molecular clusters and secondary aerosols in the atmosphere has a significant impact on the climate. Studies typically focus on the new particle formation (NPF) of sulfuric acid (SA) with a single base molecule (e.g., dimethylamine or ammonia). In this work, we examine the combinations and synergy of several bases. Specifically, we used computational quantum chemistry to perform configurational sampling (CS) of (SA)_0-4(base)_0-4 clusters with five different types of bases: ammonia (AM), methylamine (MA), dimethylamine (DMA), trimethylamine (TMA), and ethylenediamine (EDA). Overall, we studied 316 different clusters. We used a traditional multilevel funnelling sampling approach augmented by a machine-learning (ML) step. The ML made the CS of these clusters possible by significantly enhancing the speed and quality of the search for the lowest free energy configurations. Subsequently, the cluster thermodynamics properties were evaluated at the DLPNO-CCSD(T₀)/aug-cc-pVTZ//ωB97X-D/6-31++G(d,p) level of theory. The calculated binding free energies were used to evaluate the cluster stabilities for population dynamics simulations. The resultant SA-driven NPF rates and synergies of the studied bases are presented to show that DMA and EDA act as nucleators (although EDA becomes weak in large clusters), TMA acts as a catalyzer, and AM/MA is often overshadowed by strong bases.

Air pollutants, genetic susceptibility and risk of incident idiopathic pulmonary fibrosis

BACKGROUND

Air pollutants are considered as non-negligible risk factors of idiopathic pulmonary fibrosis (IPF). However, the relationship between long-term air pollution and the incidence of IPF is unknown. Our objective was to explore the associations of air pollutants with IPF risk and further assess the modification effect of genetic susceptibility.

METHODS

We used land-use regression model estimated concentrations of nitrogen dioxide (NO₂), nitrogen oxides (NO _x ) and particulate matter (fine particulate matter with diameter <2.5 μm (PM_2.5) and particulate matter with diameter <10 μm (PM₁₀)). The polygenic risk score (PRS) was constructed using 13 independent single nucleotide polymorphisms. Cox proportional hazard models were used to evaluate the associations of air pollutants with IPF risk and further investigate the modification effect of genetic susceptibility. Additionally, absolute risk was calculated.

RESULTS

Among 433 738 participants from the UK Biobank, the incidence of IPF was 27.45 per 100 000 person-years during a median follow-up of 11.78 years. The adjusted hazard ratios of IPF for each interquartile range increase in NO₂, NO _x and PM_2.5 were 1.11 (95% CI 1.03-1.19), 1.07 (95% CI 1.01-1.13) and 1.09 (95% CI 1.02-1.17), respectively. PM_2.5 had the highest population attribution risk, followed by NO _x and NO₂. There were additive interactions between NO₂, NO _x and PM_2.5 and genetic susceptibility. Participants with a high PRS and high air pollution had the highest risk of incident IPF compared with those with a low PRS and low air pollution (adjusted hazard ratio: NO₂ 3.94 (95% CI 2.77-5.60), NO _x 3.08 (95% CI 2.21-4.27), PM_2.5 3.65 (95% CI 2.60-5.13) and PM₁₀ 3.23 (95% CI 2.32-4.50)).

CONCLUSION

Long-term exposures to air pollutants may elevate the risk of incident IPF. There are additive effects of air pollutants and genetic susceptibility on IPF risk.

Polypropylene nanoplastic exposure leads to lung inflammation through p38-mediated NF-κB pathway due to mitochondrial damage

BACKGROUND

Polypropylene (PP) is used in various products such as disposable containers, spoons, and automobile parts. The disposable masks used for COVID-19 prevention mainly comprise PP, and the disposal of such masks is concerning because of the potential environmental pollution. Recent reports have suggested that weathered PP microparticles can be inhaled, however, the inhalation toxicology of PP microparticles is poorly understood.

RESULTS

Inflammatory cell numbers, reactive oxygen species (ROS) production, and the levels of inflammatory cytokines and chemokines in PP-instilled mice (2.5 or 5 mg/kg) increased significantly compared to with those in the control. Histopathological analysis of the lung tissue of PP-stimulated mice revealed lung injuries, including the infiltration of inflammatory cells into the perivascular/parenchymal space, alveolar epithelial hyperplasia, and foamy macrophage aggregates. The in vitro study indicated that PP stimulation causes mitochondrial dysfunction including mitochondrial depolarization and decreased adenosine triphosphate (ATP) levels. PP stimulation led to cytotoxicity, ROS production, increase of inflammatory cytokines, and cell deaths in A549 cells. The results showed that PP stimulation increased the p-p38 and p-NF-κB protein levels both in vivo and in vitro, while p-ERK and p-JNK remained unchanged. Interestingly, the cytotoxicity that was induced by PP exposure was regulated by p38 and ROS inhibition in A549 cells.

CONCLUSIONS

These results suggest that PP stimulation may contribute to inflammation pathogenesis via the p38 phosphorylation-mediated NF-κB pathway as a result of mitochondrial damage.

Respiratory protective effects of Korean Red Ginseng in a mouse model of particulate matter 4-induced airway inflammation

Background

Air pollution has led to an increased exposure of all living organisms to fine dust. Therefore, research efforts are being made to devise preventive and therapeutic remedies against fine dust-induced chronic diseases.

Methods

Research of the respiratory protective effects of KRG extract in a particulate matter (PM; aerodynamic diameter of <4 μm) plus diesel exhaust particle (DEP) (PM4+D)-induced airway inflammation model. Nitric oxide production, expression of pro-inflammatory mediators and cytokines, and IRAK-1, TAK-1, and MAPK pathways were examined in PM4-stimulated MH-S cells. BALB/c mice exposed to PM4+D mixture by intranasal tracheal injection three times a day for 12 days at 3 day intervals and KRGE were administered orally for 12 days. Histological of lung and trachea, and immune cell subtype analyses were performed. Expression of pro-inflammatory mediators and cytokines in bronchoalveolar lavage fluid (BALF) and lung were measured. Immunohistofluorescence staining for IRAK-1 localization in lung were also evaluated.

Results

KRGE inhibited the production of nitric oxide, the expression of pro-inflammatory mediators and cytokines, and expression and phosphorylation of all downstream factors of NF-κB, including IRAK-1 and MAPK/AP1 pathway in PM4-stimulated MH-S cells. KRGE suppressed inflammatory cell infiltration and number of immune cells, histopathologic damage, and inflammatory symptoms in the BALF and lungs induced by PM4+D; these included increased alveolar wall thickness, accumulation of collagen fibers, and TNF-α, MIP2, CXCL-1, IL-1α, and IL-17 cytokine release. Moreover, PM4 participates induce alveolar macrophage death and interleukin-1α release by associating with IRAK-1 localization was also potently inhibited by KRGE in the lungs of PM4+D-induced airway inflammation model. KRGE suppresses airway inflammatory responses, including granulocyte infiltration into the airway, by regulating the expression of chemokines and inflammatory cytokines via inhibition of IRAK-1 and MAPK pathway. Conclusion: Our results indicate the potential of KRGE to serve as an effective therapeutic agent against airway inflammation and respiratory diseases.

Occupational exposure of vehicular emissions and cardiorespiratory risk among urban metropolitan bus drivers: A cross-sectional comparative study

BACKGROUND

Vehicular emissions on long-term exposure predispose metropolitan bus drivers to cardiorespiratory ailments.

OBJECTIVE

To evaluate the cardiorespiratory risk of urban metropolitan bus drivers related to vehicular emission exposure.

METHODS

Bus drivers (with service >5 years, n = 254) and their administrative controls (primarily engaged in indoor white collared jobs, n = 73) were recruited. Demographic, occupational and clinical details were collected through pre-validated standardized format. Pulmonary Function Test (PFT) and lipid profile were carried out with standard protocol. Risk for cardiovascular events for preceding 10-years was estimated with WHO/ISH risk prediction chart and QRISK3 score. Exposure assessments for particulate matter (PM) were performed for both groups while duty hours.

RESULTS

Exposure of drivers to PM2.5 six times and PM10 five times higher in comparison to administration staff (PM2.5- 970.9 v/s 145.0μg/m3 TWA and PM10- 1111.7 v/s 233.8μg/m3 TWA). Bus drivers exhibited significantly higher prevalence of respiratory symptoms (dyspnea-25% v/s 6.8% and cough-20.1% v/s 9.8%) and compromised PFT (obstructive-21% v/s 5.7% and restrictive-4.2% v/s 2.9%) in comparison to controls. Multivariate regression statistics reveal a significant decline for FEV1/FVC and FEV25-75 % among bus drivers compared to controls, controlling the influence of physiological and environmental factors. The difference between predicted cardiac age and their respective chronological age was twice higher (8.3 v/s 4.3 years) among drivers compared to their administration staff.

CONCLUSION

Bus drivers were exposed to high levels of outdoor air pollutants. Further, the drivers exhibited higher risk for ischemic attack and obstructive airway diseases as compared to administration staff.

Airborne particulate matter (PM10) induces cell invasion through Aryl Hydrocarbon Receptor and Activator Protein 1 (AP-1) pathway deregulation in A549 lung epithelial cells

BACKGROUND

Particulate matter with an aerodynamic size ≤ 10 μm (PM₁₀) is a risk factor for lung cancer development, mainly because some components are highly toxic. Polycyclic aromatic hydrocarbons (PAHs) are present in PM₁₀, such as benzo[a]pyrene (BaP), which is a well-known genotoxic and carcinogenic compound to humans, capable of activating AP-1 transcription factor family genes through the Aryl Hydrocarbon Receptor (AhR). Because effects of BaP include metalloprotease 9 (MMP-9) activation, cell invasion, and other pathways related to carcinogenesis, we aimed to demonstrate that PM₁₀ (10 µg/cm²) exposure induces the activation of AP-1 family members as well as cell invasion in lung epithelial cells, through AhR pathway.

METHODS AND RESULTS

The role of the AhR gene in cells exposed to PM₁₀ (10 µg/cm²) and BaP (1µM) for 48 h was evaluated using AhR-targeted interference siRNA. Then, the AP-1 family members (c-Jun, Jun B, Jun D, Fos B, C-Fos, and Fra-1), the levels/activity of MMP-9, and cell invasion were analyzed. We found that PM₁₀ increased AhR levels and promoted its nuclear localization in A549 treated cells. Also, PM₁₀ and BaP deregulated the activity of AP-1 family members. Moreover, PM₁₀ upregulated the secretion and activity of MMP-9 through AhR, while BaP had no effect. Finally, we found that cell invasion in A549 cells exposed to PM₁₀ and BaP is modulated by AhR.

CONCLUSION

Our results demonstrated that PM₁₀ exposure induces upregulation of the c-Jun, Jun B, and Fra-1 activity, the expression/activity of MMP-9, and the cell invasion in lung epithelial cells, effects mediated through the AhR. Also, the Fos B and C-Fos activity were downregulated. In addition, the effects induced by PM₁₀ exposure were like those induced by BaP, which highlights the potentially toxic effects of the PM₁₀ mixture in lung epithelial cells.

The Effects and Pathogenesis of PM2.5 and Its Components on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), a heterogeneous disease, is the leading cause of death worldwide. In recent years, air pollution, especially particulate matter (PM), has been widely studied as a contributing factor to COPD. As an essential component of PM, PM2.5 is associated with COPD prevalence, morbidity, and acute exacerbations. However, the specific pathogenic mechanisms were still unclear and deserve further research. The diversity and complexity of PM2.5 components make it challenging to get its accurate effects and mechanisms for COPD. It has been determined that the most toxic PM2.5 components are metals, polycyclic aromatic hydrocarbons (PAHs), carbonaceous particles (CPs), and other organic compounds. PM2.5-induced cytokine release and oxidative stress are the main mechanisms reported leading to COPD. Nonnegligibly, the microorganism in PM 2.5 may directly cause mononuclear inflammation or break the microorganism balance contributing to the development and exacerbation of COPD. This review focuses on the pathophysiology and consequences of PM2.5 and its components on COPD.

Chemokine expression in human 3-dimensional cultured epidermis exposed to PM2.5 collected by cyclonic separation

Fine particulate matter (PM2.5) exposure has a risk of inducing several health problems, especially in the respiratory tract. The skin is the largest organ of the human body and is therefore the primary target of PM2.5. In this study, we examined the effects of PM2.5 on the skin using a human 3-dimensional cultured epidermis model. PM2.5 was collected by cyclonic separation in Yokohama, Japan. Global analysis of 34 proteins released from the epidermis revealed that the chemokines, chemokine C-X-C motif ligand 1 (CXCL1) and interleukin 8 (IL-8), were significantly increased in response to PM2.5 exposure. These chemokines stimulated neutrophil chemotaxis in a C-X-C motif chemokine receptor 2-dependent manner. The oxidative stress and signal transducer and activator of transcription 3 pathways may be involved in the increased expression of CXCL1 and IL-8 in the human epidermis model. Interestingly, in the HaCaT human keratinocyte cell line, PM2.5 did not affect chemokine expression but did induce IL-6 expression, suggesting a different effect of PM2.5 between the epidermis model and HaCaT cells. Overall, PM2.5 could induce the epidermis to release chemokines, followed by neutrophil activation, which might cause an unregulated inflammatory reaction in the skin.

N-acetylcysteine decreases lung inflammation and fibrosis by modulating ROS and Nrf2 in mice model exposed to particulate matter

Background and Objectives: Air pollutants can induce and incite airway diseases such as asthma. N-acetylcysteine (NAC) affects signaling pathways involved in apoptosis, angiogenesis, cell growth and arrest, redox-regulated gene expression, and the inflammatory response. However, it is not known how NAC change redox-regulated gene expression in asthma mouse model exposed to particulate matter (PM). To investigate the effects of NAC on asthma mice exposed to PM through Reactive oxygen species (ROS), nuclear factor erythroid 2-related factor 2 (Nrf2), and mucin 5 (Muc5).Methods: To investigate the effects of NAC (100 mg/kg) on redox-regulated gene expression and lung fibrosis in a mouse model of asthma exposed to PM. A mice model of asthma induced by ovalbumin (OVA) or OVA plus titanium dioxide (OVA + TiO₂) was established using wild-type BALB/c female mice, and the levels of Nrf2 and mucin 5AC (Muc5ac) proteins following NAC treatment were examined by Western blotting and immunostaining. In addition, the protein levels of ROS were checked.Results: Airway hyperresponsiveness and inflammation, goblet cell hyperplasia, and lung fibrosis were higher in OVA, OVA + TiO₂ mice than in control mice. NAC diminished OVA + TiO₂-induced airway hyperresponsiveness and inflammation, goblet cell hyperplasia, and lung fibrosis. Levels of ROS, Nrf2, and Muc5ac protein were higher in lung tissue from OVA + TiO₂ mice than that from control mice and were decreased by treatment with NAC.Conclusions: NAC reduce airway inflammation and responsiveness, goblet cell hyperplasia, and lung fibrosis by modulating ROS and Nrf2.

Association of inflammation and lung function decline caused by personal PM2.5 exposure: a machine learning approach in time-series data

Numerous studies focused on the association between lung function impairment and inflammation caused by fine particulate matter (PM_2.5), but the causal relationships are difficult to clarify. In the current study, twenty healthy Chinese young adults who participated in 7 days of observation every four seasons were enrolled, and autoregression models (AM) and classification and regression trees (CART) in a machine learning framework were applied to analyze the association among PM_2.5 exposure, inflammation, and lung function from a data structure perspective. There were strong cross-correlations between personal dose of PM_2.5 (Dw) and lung functions (vital capacity (VC), forced vital capacity (FVC), etc.). These cross-correlation coefficients were associated with inflammatory indicators (uteroglobin (UG), serum amyloid (SAA), and fractional exhaled nitric oxide (FeNO)). CART reported that inflammatory indicators UG and SAA had the predictive ability of the directional association between Dw and FVC at 1-day lag and that high levels of UG and SAA predicted that PM_2.5 exposure induced lung function decline. Consistently, lower lung function indicators at a 2-day lag after personal PM_2.5 exposure predicted the high value of inflammatory indicator FeNO. Taken together, we applied machine learning algorithms to analyze repeated measurement data, finding that inflammation and lung function decline caused by PM_2.5 could affect each other.

Mechanistic Insights into the Impact of Air Pollution on Pneumococcal Pathogenesis and Transmission

Streptococcus pneumoniae (the pneumococcus) is the leading cause of pneumonia and bacterial meningitis. A number of recent studies indicate an association between the incidence of pneumococcal disease and exposure to air pollution. Although the epidemiological evidence is substantial, the underlying mechanisms by which the various components of air pollution (particulate matter and gases such as NO2 and SO2) can increase susceptibility to pneumococcal infection are less well understood. In this review, we summarize the various effects air pollution components have on pneumococcal pathogenesis and transmission; exposure to air pollution can enhance host susceptibility to pneumococcal colonization by impairing the mucociliary activity of the airway mucosa, reducing the function and production of key antimicrobial peptides, and upregulating an important pneumococcal adherence factor on respiratory epithelial cells. Air pollutant exposure can also impair the phagocytic killing ability of macrophages, permitting increased replication of S. pneumoniae. In addition, particulate matter has been shown to activate various extra- and intracellular receptors of airway epithelial cells, which may lead to increased proinflammatory cytokine production. This increases recruitment of innate immune cells, including macrophages and neutrophils. The inflammatory response that ensues may result in significant tissue damage, thereby increasing susceptibility to invasive disease, because it allows S. pneumoniae access to the underlying tissues and blood. This review provides an in-depth understanding of the interaction between air pollution and the pneumococcus, which has the potential to aid the development of novel treatments or alternative strategies to prevent disease, especially in areas with high concentrations of air pollution.

The role of PP2A /NLRP3 signaling pathway in ambient particulate matter 2.5 induced lung injury

Ambient particulate matter 2.5 (PM_2.5) exposure has been linked to pulmonary fibrosis. However, the key signaling pathways remained unclear. In the present study, we applied a mouse model with myeloid-specific deletion of Ppp2r1a gene (encoding protein phosphatase 2 A (PP2A) A subunit) to identify the key signaling pathways involved in PM_2.5-induced pulmonary fibrosis. PP2A Aα^-/- homozygote mice and matched wild-type (WT) littermates were exposed to filtered air (FA), unfiltered air (UA), and concentrated PM_2.5 (CA) in a real-ambient PM exposure system for 8 weeks and 16 weeks, respectively. The mice exposed to PM_2.5 displayed a progressive inflammation and pulmonary fibrosis. Moreover, the expressions of NLRP3, pro-caspase-1, caspase-1, ASC and IL-1β were increased in mice lung following PM_2.5 exposure, indicating PM_2.5 exposure caused pulmonary inflammation by the NLRP3 pathways activation. Furthermore, the effects of PM exposure on pulmonary inflammation, pulmonary fibrosis, oxidative stress, and pulmonary function damage were significantly enhanced in PP2A^-/- mice compared to WT mice, indicating the role of PP2A in the regulation of pulmonary injury induced by PM exposure. In vitro study confirmed that PP2A was involved in the PM_2.5-induced inflammation response and NLRP3 inflammasome activation. Importantly, we identified PP2A regulated the activation of NLRP3 pathways by direct dephosphorylating IRE1α in response to PM_2.5 exposure. Taken together, our results demonstrated that PP2A-IRE1α-NLRP3 signaling pathway played a crucial role in regulating the inflammation response, triggering the lung fibrogenesis upon PM_2.5 exposure. Our findings provide new insights into regulatory role of PP2A in human diseases upon the PM exposure.

PM2.5 air pollution exposure and nonalcoholic fatty liver disease in the Nationwide Inpatient Sample

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. Particulate matter air pollution <2.5 μm in diameter (PM_2.5) is a ubiquitous exposure primarily produced from fossil fuel combustion. Previous epidemiologic studies have been mixed. The objective of this study was to examine the association between ambient PM_2.5 exposure and NAFLD among hospitalized patients in the Nationwide Inpatient Sample (NIS).

METHODS

We conducted a cross-sectional analysis of hospitalizations from 2001 to 2011 using the NIS, the largest nationally representative all-payer inpatient care administrative database in the United States. Average annual PM_2.5 exposure was estimated by linking census tracts (based on NIS-provided hospital ZIP Codes) with a spatiotemporal exposure model. Clinical conditions were identified using hospital discharge diagnosis codes. Multivariable logistic regression incorporating discharge weights was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between PM_2.5 exposure and odds of NAFLD among hospitalized patients adjusting for age, sex, race/ethnicity, year, individual- and area-level socioeconomic status, urbanicity, region, obesity, diabetes, metabolic syndrome, impaired fasting glucose, dyslipidemia, hypertension, obstructive sleep apnea, and smoking.

RESULTS

There were 269,705 hospitalized patients with NAFLD from 2001 to 2011 (total unweighted n = 45,433,392 hospitalizations). Higher ambient PM_2.5 exposure was associated with increased odds of NAFLD among hospitalized patients (adjusted OR: 1.24 per 10 μg/m³ increase, 95% CI 1.15-1.33, p < 0.01). There were statistically significant interactions between PM_2.5 exposure and age, race/ethnicity, diabetes, smoking, and region, with stronger positive associations among patients who were aged ≥45 years, non-Hispanic White or Asian/Pacific Islander, non-diabetics, non-smokers, or in the Midwest and West regions, respectively.

CONCLUSIONS

In this nationwide cross-sectional analysis of the NIS database, there was a positive association between ambient PM_2.5 exposure and odds of NAFLD among hospitalized patients. Future research should examine the effects of long-term historical PM_2.5 exposure and incident NAFLD cases.

: Short-term effects of exposure to particulate matter on hospital admissions for asthma and chronic obstructive pulmonary disease

We investigated the effects of particulate matter (PM) factors on hospitalization rates for asthma and chronic obstructive pulmonary disease (COPD). We obtained data on pollutants-PM10, PM2.5-in Seoul, South Korea. We also investigated data for asthma and COPD exacerbation that required hospitalization from 2006 to 2016. We used a time-stratified case-crossover design and generalized additive models with log transformation to assess adjusted risk, and conditional logistic regression was performed to analyze these data. Our study showed that PM10 and PM2.5, on different best lag days, were associated with increased risks of COPD or asthma hospitalization. The odds ratios (ORs) for each per-unit increase in PM10 and PM2.5 were higher in patients with male asthma (PM10: OR, 1.012; 95% confidence interval [CI], 1.008-1.016 and PM2.5: OR, 1.015; 95% CI, 1008-1.023), preschool asthma (PM10: OR, 1.015; 95% CI, 1.006-1.015 and PM2.5: OR, 1.015; 95% CI, 1.009-1.024), male COPD (PM10: OR, 1.012; 95% CI, 1.005-1.019 and PM2.5: OR, 1.013; 95% CI, 1.000-1.026), and senior COPD (PM10: OR, 1.016; 95% CI, 1.008-1.024 and PM2.5: OR, 1.022; 95% CI, 1.007-1.036). Increasing PM levels increased hospitalizations for asthma and COPD. Additionally, the consequences may be different according to age and sex, and PM2.5 may have a more significant effect on airway disease patients than PM10.

Sub-toxic events induced by truck speed-facilitated PM2.5 and its counteraction by epigallocatechin-3-gallate in A549 human lung cells

To distinguish the influences of fuel type and truck speed on chemical composition and sub-toxic effects of particulates (PM2.5) from engine emissions, biomarkers-interleukin-6 (IL-6), cytochrome P450 (CYP) 1A1, heme oxygenase (HO)-1, and NADPH-quinone oxidoreductase (NQO)-1-were studied in A549 human lung cells. Fuel type and truck speed preferentially affected the quantity and ion/polycyclic aromatic hydrocarbon (PAH) composition of PM2.5, respectively. Under idling operation, phenanthrene was the most abundant PAH. At high speed, more than 50% of the PAHs had high molecular weight (HMW), of which benzo[a]pyrene (B[a]P), benzo[ghi]perylene (B[ghi]P), and indeno[1,2,3-cd]pyrene (I[cd]P) were the main PAHs. B[a]P, B[ghi]P, and I[cd]P caused potent induction of IL-6, CYP1A1, and NQO-1, whereas phenanthrene mildly induced CYP1A1. Based on the PAH-mediated induction, the predicted increases in biomarkers were positively correlated with the measured increases. HMW-PAHs contribute to the biomarker induction by PM2.5, at high speed, which was reduced by co-exposure to epigallocatechin-3-gallate.

Effects of air pollution on human health - Mechanistic evidence suggested by in vitro and in vivo modelling

Airborne particulate matter (PM) comprises both solid and liquid particles, including carbon, sulphates, nitrate, and toxic heavy metals, which can induce oxidative stress and inflammation after inhalation. These changes occur both in the lung and systemically, due to the ability of the small-sized PM (i.e. diameters ≤2.5 μm, PM_2.5) to enter and circulate in the bloodstream. As such, in 2016, airborne PM caused ∼4.2 million premature deaths worldwide. Acute exposure to high levels of airborne PM (eg. during wildfires) can exacerbate pre-existing illnesses leading to hospitalisation, such as in those with asthma and coronary heart disease. Prolonged exposure to PM can increase the risk of non-communicable chronic diseases affecting the brain, lung, heart, liver, and kidney, although the latter is less well studied. Given the breadth of potential disease, it is critical to understand the mechanisms underlying airborne PM exposure-induced disorders. Establishing aetiology in humans is difficult, therefore, in-vitro and in-vivo studies can provide mechanistic insights. We describe acute health effects (e.g. exacerbations of asthma) and long term health effects such as the induction of chronic inflammatory lung disease, and effects outside the lung (e.g. liver and renal change). We will focus on oxidative stress and inflammation as this is the common mechanism of PM-induced disease, which may be used to develop effective treatments to mitigate the adverse health effect of PM exposure.

Particulate matter 2.5 exposure induces epithelial-mesenchymal transition via PI3K/AKT/mTOR pathway in human retinal pigment epithelial ARPE-19 cells

Exposure to particulate matter 2.5 (PM2.5) has been linked to ocular surface diseases, yet knowledge of the molecular mechanism impacted on retina pathogenesis is limited. Therefore, the purpose of this study was to explore the effects and involved factors of PM2.5 exposure in human retinal pigment epithelial APRE-19 cells. Our data revealed a decreased cell viability and an increased migratory ability in APRE-19 cells after PM2.5 stimulation. The MMP-2 and MMP-9 protein levels were markedly increased while the MMPs regulators TIMP-1 and TIMP-2 were significantly reduced in PM2.5-exposed APRE-19 cells. PM2.5 also increased pro-MMP-2 expression in the cell culture supernatants. Additionally, PM2.5 promoted the EMT markers through the activation of PI3K/AKT/mTOR pathway. Moreover, the ICAM-1 production was also remarkably increased by PM2.5 but reduced by PI3K/AKT inhibitor LY294002 in APRE-19 cells. Taken together, these results suggest that PM2.5 promotes EMT in a PI3K/AKT/mTOR-dependent manner in the retinal pigment epithelium.

Inflammation resolution in environmental pulmonary health and morbidity

Inflammation and resolution are dynamic processes comprised of inflammatory activation and neutrophil influx, followed by mediator catabolism and efferocytosis. These critical pathways ensure a return to homeostasis and promote repair. Over the past decade research has shown that diverse mediators play a role in the active process of resolution. Specialized pro-resolving mediators (SPMs), biosynthesized from fatty acids, are released during inflammation to facilitate resolution and are deficient in a variety of lung disorders. Failed resolution results in remodeling and cellular deposition through pro-fibrotic myofibroblast expansion that irreversibly narrows the airways and worsens lung function. Recent studies indicate environmental exposures may perturb and deregulate critical resolution pathways. Environmental xenobiotics induce lung inflammation and generate reactive metabolites that promote oxidative stress, injuring the respiratory mucosa and impairing gas-exchange. This warrants recognition of xenobiotic associated molecular patterns (XAMPs) as new signals in the field of inflammation biology, as many environmental chemicals generate free radicals capable of initiating the inflammatory response. Recent studies suggest that unresolved, persistent inflammation impacts both resolution pathways and endogenous regulatory mediators, compromising lung function, which over time can progress to chronic lung disease. Chronic ozone (O3) exposure overwhelms successful resolution, and in susceptible individuals promotes asthma onset. The industrial contaminant cadmium (Cd) bioaccumulates in the lung to impair resolution, and recurrent inflammation can result in chronic obstructive pulmonary disease (COPD). Persistent particulate matter (PM) exposure increases systemic cardiopulmonary inflammation, which reduces lung function and can exacerbate asthma, COPD, and idiopathic pulmonary fibrosis (IPF). While recurrent inflammation underlies environmentally induced pulmonary morbidity and may drive the disease process, our understanding of inflammation resolution in this context is limited. This review aims to explore inflammation resolution biology and its role in chronic environmental lung disease(s).

The role of estrogen receptor β in fine particulate matter (PM2.5) organic extract-induced pulmonary inflammation in female and male mice

Fine particulate matter organic extract (Po) was reported to promote inflammation in the lung. Sex differences were reported in many inflammatory diseases. In this study, we investigated the effects of Po exposure on pulmonary inflammatory response and evaluated the role of sex in this process. While mice were exposed to 100 µg/m³ Po for 12 weeks by an inhalation exposure system, the lung histopathological analysis shown obvious inflammation, the cell numbers in bronchoalveolar lavage fluid (BALF) were significantly increased, and most inflammatory cytokines in BALF were upregulated. The results of factorial analysis of variance shown that there was an interaction between sex and Po exposure in the inflammatory cell numbers and the levels of tumor necrosis factor-α (TNF-α), interleukin-5 (IL-5), and growth-related oncogene/keratinocyte chemoattractant (GRO/KC). Notably, these changes and interactions were diminished while Po-exposed mice were administered with the estrogen receptor β (ERβ) antagonist. We speculated that sex might affect the levels of inflammatory indicators in BALF of Po-exposed mice and female mice were more prone to inflammation while exposed to Po. Moreover, ERβ was involved in these processes. To our knowledge, this is the first investigation about the role of sex in Po-induced adverse effects.

Pyroptosis participates in PM2.5-induced air-blood barrier dysfunction

Epidemiological studies have shown that particulate matters with diameter less than 2.5 μm (PM_2.5) play an important role in inducing and promoting respiratory diseases, but its underlying mechanism remains to be explored. The air-blood barrier, also known as the alveolar-capillary barrier, is the key element of the lung, working as the site of oxygen and carbon dioxide exchange between pulmonary vasculatures. In this study, a mouse PM_2.5 exposure model was established, which leads to an induced lung injury and air-blood barrier disruption. Oxidative stress and pyroptosis were observed in this process. After reducing the oxidative stress by N-acetyl-L-cysteine (NAC) treatment, the air-blood barrier function was improved and the effect of PM_2.5 was alleviated. The level of pyroptosis and related pathway were also effectively relieved. These results indicate that acute PM_2.5 exposure can cause lung injury and the alveolar-capillary barrier disruption by inducing reactive oxygen species (ROS) with the participation of pyroptosis pathway.