Alteration of DNA methylation induced by PM2.5 in human bronchial epithelial cells

Carbonaceous cores serve as surrogates for environmental particulate matter inducing vascular endothelial inflammation via inflammasome activation

Ambient particulate matter (PM) exposure is a known risk factor for cardiovascular diseases. Epidemiological studies have shown the association between PM exposure and vascular complications, including vasculitis, embolism, hypertension, stroke, and atherosclerosis. However, the exact mechanisms underlying its vascular toxicity, especially in relation to short-term exposures, remain incompletely understood. This study investigates the role of PM and its carbonaceous cores in driving vascular endothelial inflammation via inflammasome activation. We hypothesized that PM SRM1648a exposure induces vascular endothelial inflammation through oxidative stress and inflammasome activation. Short-term exposure to PM SRM1648a was assessed in BALB/c mice for systemic inflammation and oxidative stress biomarkers, alongside in vitro studies in HUVECs and EA.hy926 endothelial cells to elucidate inflammasome activation pathways. PM SRM1648a exposure significantly altered redox balance and cytokine profiles in mice and upregulated NLRP3/NLRC4 inflammasomes in vascular endothelial cells, leading to caspase-1/IL-1β activation. Intriguingly, pyroptosis was not the primary mode of cell death. In vitro studies demonstrated that antioxidants glutathione monoethyl ester effectively mitigated oxidative stress and inflammasome activation in endothelial cells. This study highlights the critical role of ROS-mediated inflammasome activation in vascular inflammation induced by PM SRM1648a, with carbon-based cores as key contributors.

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.

Biomarkers for the adverse effects on respiratory system health associated with atmospheric particulate matter exposure

Large amounts of epidemiological evidence have confirmed the atmospheric particulate matter (PM_2.5) exposure was positively correlated with the morbidity and mortality of respiratory diseases. Nevertheless, its pathogenesis remains incompletely understood, probably resulting from the activation of oxidative stress, inflammation, altered genetic and epigenetic modifications in the lung upon PM_2.5 exposure. Currently, biomarker investigations have been widely used in epidemiological and toxicological studies, which may help in understanding the biologic mechanisms underlying PM_2.5-elicited adverse health outcomes. Here, the emerging biomarkers to indicate PM_2.5-respiratory system interactions were summarized, primarily related to oxidative stress (ROS, MDA, GSH, etc.), inflammation (Interleukins, FE_NO, CC16, etc.), DNA damage (8-OHdG, γH2AX, OGG1) and also epigenetic modulation (DNA methylation, histone modification, microRNAs). The identified biomarkers shed light on PM_2.5-elicited inflammation, fibrogenesis and carcinogenesis, thus may favor more precise interventions in public health. It is worth noting that some inconsistent findings may possibly relate to the inter-study differentials in the airborne PM_2.5 sample, exposure mode and targeted subjects, as well as methodological issues. Further research, particularly by -omics technique to identify novel, specific biomarkers, is warranted to illuminate the causal relationship between PM_2.5 pollution and deleterious lung outcomes.