Chemical Characteristics and Cytotoxicity to GC-2spd(ts) Cells of PM2.5 in Nanjing Jiangbei New Area from 2015 to 2019

Exosomal miR-129-2-3p promotes airway epithelial barrier disruption in PM2.5-aggravated asthma

Particulate matter 2.5 (PM2.5) exposure is intricately linked to asthma exacerbations. Damage to the airway epithelial barrier function serves as an initiating factor for asthma attacks and worsening symptoms. In recent years, numerous exosomal microRNAs (miRNAs) have emerged as potential biomarkers for diagnosing asthma. However, the mechanisms by which PM2.5-induced exosomes exacerbate asthma remain unclear. This study aims to investigate the role of exosomal miR-129-2-3p in regulating airway epithelial cell barrier function, its potential targets, and signaling pathways involved in PM2.5-induced aggravation of asthma. In this study, miR-129-2-3p is highly expressed in plasma exosomes from patients with asthma, mouse lung tissue and plasma exosomes, and exosomes produced by PM2.5-stimulated 16HBE cells. Moreover, the exposure level of PM2.5 is positively correlated with exosomal miR-129-2-3p in plasma in patients with asthma. As the concentration of PM2.5 increases, the synthesis of connexin (ZO-1, occludin, and E-cadherin) is gradually weakened, while the content of inflammatory factors (IL-6, IL-8, and TNF-α) is notably upregulated in PM2.5 exacerbated asthmatic mice. PM2.5-induced exosomes can decrease the level of connexin, enhance cell permeability and promote the secretion of inflammatory factors in 16HBE cells. TIAM1, a specific target gene for miR-129-2-3p, regulates the synthesis of connexin. Exosomal miR-129-2-3p exacerbates airway epithelial barrier dysfunction by targeted inhibition of the TIAM1/RAC1/PAK1 signaling pathway in PM2.5 aggravated asthma. In contrast, blocking miR-129-2-3p may be an alternative approach to therapeutic intervention in asthma.

Risk of heavy metal(loid) compositions in fine particulate matter on acute cardiovascular mortality: a poisson analysis in Anyang, China

Fine particulate matter (PM2.5) is a risk factor of cardiovascular disease. Associations between PM2.5 compositions and cardiovascular disease are a point of special interest but inconsistent. This study aimed to explore the cardiovascular effects of heavy metal(loid) compositions in PM2.5. Data for mortality, air pollutants and meteorological factors in Anyang, China from 2017 to 2021 were collected. Heavy metal(loid) in PM2.5 were monitored and examined monthly. A Case-crossover design was applied to the estimated data set. The interquartile range increase in cadmium (Cd), antimony (Sb) and arsenic (As) at lag 1 was associated with increment of 8.1% (95% CI: 3.3, 13.2), 4.8% (95% CI: 0.2, 9.5) and 3.5% (95% CI: 1.1, 6.0) cardiovascular mortality. Selenium in lag 2 was inversely associated with cerebrovascular mortality (RR = 0.920 95% CI: 0.862, 0.983). Current-day exposure of aluminum was positively associated with mortality from ischemic heart disease (RR = 1.083 95% CI: 1.001, 1.172). Stratified analysis indicated sex, age and season modified the cardiovascular effects of As (P < 0.05). Our study reveals that heavy metal(loid) play key roles in adverse effects of PM2.5. Cd, Sb and As were significant risk factors of cardiovascular mortality. These findings have potential implications for accurate air pollutants control and management to improve public health benefits.

Comparative in vitro toxicological effects of water-soluble and insoluble components of atmospheric PM2.5 on human lung cells

Fine particulates in city air significantly impact human health, but the hazardous compositional mechanisms are still unclear. Besides the toxicity of environmental PM2.5 to in vitro human lung epithelial cells (A549), the independent cytotoxicity of PM2.5-bound water-soluble (WS-PM2.5) and water-insoluble (WIS-PM2.5) fractions were also compared by cell viability, oxidative stress (reactive oxygen species, ROS), and inflammatory injury (IL-6 and TNF-α). The cytotoxicity of PM2.5 varied significantly by sampling season and place, with degrees greater in winter and spring than in summer and autumn, related to corresponding trend of air PM2.5 level, and also higher in industrial than urban site, although their PM2.5 pollution levels were comparable. The PM2.5 bound metals (Ni, Cr, Fe, and Mn) may contribute to cellular injury. Both WS-PM2.5 and WIS-PM2.5 posed significant cytotoxicity, that WS-PM2.5 was more harmful than WIS-PM2.5 in terms of decreasing cell viability and increasing inflammatory cytokines production. In particular, industrial samples were usually more toxic than urban samples, and those from summer were generally less toxic than other seasons. Hence, in order to mitigate the health risks of PM2.5 pollution, the crucial targets might be components of heavy metals and soluble fractions, and sources in industrial areas, especially during the cold seasons.

Toxicological responses of A549 and HCE-T cells exposed to fine particulate matter at the air-liquid interface

Fine particulate matter (PM2.5) can enter the human body in various ways and have adverse effects on human health. Human lungs and eyes are exposed to the air for a long time and are the first to be exposed to PM2.5. The "liquid immersion exposure method" has some limitations that prevent it from fully reflecting the toxic effects of particulate matter on the human body. In this study, the collected PM2.5 samples were chemically analyzed. An air-liquid interface (ALI) model with a high correlation to the in vivo environment was established based on human lung epithelial cells (A549) and immortalized human corneal epithelial cells (HCE-T). The VITROCELL Cloud 12 system was used to distribute PM2.5 on the cells evenly. After exposure for 6 h and 24 h, cell viability, apoptosis rate, reactive oxygen species (ROS) level, expression of inflammatory factors, and deoxyribonucleic acid (DNA) damage were measured. The results demonstrated significant dose- and time-dependent effects of PM2.5 on cell viability, cell apoptosis, ROS generation, and DNA damage at the ALI, while the inflammatory factors showed dose-dependent effects only. It should be noted that even short exposure to low doses of PM2.5 can cause cell DNA double-strand breaks and increased expression of γ-H2AX, indicating significant genotoxicity of PM2.5. Increased abundance of ROS in cells plays a crucial role in the cytotoxicity induced by PM2.5 exposure These findings emphasize the significant cellular damage and genotoxicity that may result from short-term exposure to low levels of PM2.5.

New health index derived from oxidative potential and cell toxicity of fine particulate matter to assess its potential health effect

Toxicological data and exposure levels of fine particulate matters (PM2.5) are necessary to better understand their health effects. Simultaneous measurements of PM2.5 oxidative potential (OP) and cell toxicity in urban areas (Beijing, China and Gwangju, Korea) reveal their dependence on chemical composition. Notably, acids (Polar), benzocarboxylic acids, and Pb were the chemical components that affected both OP and cell toxicity. OP varied more significantly among different locations and seasons (winter and summer) than cell toxicity. Using the measured OP, cell toxicity, and PM2.5 concentration, a health index was developed to better assess the potential health effects of PM2.5. The health index was related to the sources of PM2.5 derived from the measured chemical components. The contributions of secondary organic aerosols and dust to the proposed health index were more significant than their contributions to PM2.5 mass. The developed regression equation was used to predict the health effect of PM2.5 without further toxicity measurements. This new index could be a valuable health metric that provides information beyond just the PM2.5 concentration level.

The role of ROS-pyroptosis in PM2.5 induced air-blood barrier destruction

Fine particulate matter (PM2.5) has attracted increasing attention due to its health-threatening effects. Although numerous studies have investigated the impact of PM2.5 on lung injuries, the specific mechanisms underlying the damage to the air-blood barrier after exposure to PM2.5 remain unclear. In this study, we established an in vitro co-culture system using lung epithelial cells and capillary endothelial cells. Our findings indicated that the tight junction (TJ) proteins were up-regulated in the co-cultured system compared to the monolayer-cultured cells, suggesting the establishment of a more closely connected in vitro system. Following exposure to PM2.5, we observed damage to the air-blood barrier in vitro. Concurrently, PM2.5 exposure induced significant oxidative stress and activated the NLRP3 inflammasome-mediated pyroptosis pathway. When oxidative stress was inhibited, we observed a decrease in pyroptosis and an increase in TJ protein levels. Additionally, disulfiram reversed the adverse effects of PM2.5, effectively suppressing pyroptosis and ameliorating air-blood barrier dysfunction. Our results indicate that the oxidative stress-pyroptosis pathway plays a critical role in the disruption of the air-blood barrier induced by PM2.5 exposure. Disulfiram may represent a promising therapeutic option for mitigating PM2.5-related lung damage.