Effect of water-soluble PM10 on the production of TNF-α by human monocytes and induction of apoptosis in A549 human lung epithelial cells

Mechanisms of PM10 Disruption of the Nrf2 Pathway in Cornea

We have previously shown that PM10 exposure causes oxidative stress and reduces Nrf2 protein levels, and SKQ1 pre-treatment protects against this damage in human corneal epithelial cells (HCE-2). The current study focuses on uncovering the mechanisms underlying acute PM10 toxicity and SKQ1-mediated protection. HCE-2 were pre-treated with SKQ1 and then exposed to 100 μg/mL PM10. Cell viability, oxidative stress markers, programmed cell death, DNA damage, senescence markers, and pro-inflammatory cytokines were analyzed. Nrf2 cellular location and its transcriptional activity were determined. Effects of the Nrf2 inhibitor ML385 were similarly evaluated. Data showed that PM10 decreased cell viability, Nrf2 transcriptional activity, and mRNA levels of antioxidant enzymes, but increased p-PI3K, p-NFκB, COX-2, and iNOS proteins levels. Additionally, PM10 exposure significantly increased DNA damage, phosphor-p53, p16 and p21 protein levels, and β-galactosidase (β-gal) staining, which confirmed the senescence. SKQ1 pre-treatment reversed these effects. ML385 lowered the Nrf2 protein levels and mRNA levels of its downstream targets. ML385 also abrogated the protective effects of SKQ1 against PM10 toxicity by preventing the restoration of cell viability and reduced oxidative stress. In conclusion, PM10 induces inflammation, reduces Nrf2 transcriptional activity, and causes DNA damage, leading to a senescence-like phenotype, which is prevented by SKQ1.

The impact of meteorological parameters on PM10 and visibility during the Middle Eastern dust storms

Air pollution is one of the most pressing issues in populated Middle Eastern cities, in particular for the city of Ahvaz, Iran, imposing deleterious effects on the environment, public health, economy, culture, and other sectors. In this study, we investigate the relationship between meteorological parameters, PM₁₀, AOD, air mass source origin, and visibility during severe desert dust storms (Average_3h PM₁₀ > 3200 µg m^-3) between 2009 and 2012. Six of seven such events occurred between February and March. Interestingly, for the seven cases there was always an alarming PM₁₀ mass concentration peak (137-553 µg m^-3) between 12:00-18:00 (local time) that was 18-24 h before the dominant peak of the storm (3279-4899 µg m^-3). The maximum wind speed over the multi-day periods examined for the dust storms is usually observed 6 h before the alarming PM₁₀ peak. The minimum relative humidity, dew point temperature and air pressure occurred ± 3 h around the time of the alarming PM₁₀ peak. Wind speed was the meteorological parameter that was consistently higher around the time of the first peak as compared to the second peak, with the reverse being true for sea level pressure. Based on four years of daily data in Ahvaz, PM₁₀ was positively correlated with wind speed and air temperature and inversely correlated with sea level pressure and RH. An empirically-derived equation with R² = 0.95 is reported to estimate the maximum PM₁₀ concentration for severe desert dust events in the study region based on meteorological parameters. Finally, AOD is shown to correlate strongly (R² = 0.86) with PM₁₀ during periods with severe desert dust storms in the region.

Particulate Matter-Induced Cardiovascular Dysfunction: A Mechanistic Insight

Air pollution and particulate matter (PM) are significant factors for adverse health effects most prominently cardiovascular disease (CVD). PM is produced from various sources, which include both natural and anthropogenic. It is composed of biological components, organic compounds, minerals, and metals, which are responsible for inducing inflammation and adverse health effects. However, the adverse effects are related to PM size distribution. Finer particles are a significant cause of cardiovascular events. This review discusses the direct and indirect mechanisms of PM-induced CVD like myocardial infarction, the elevation of blood pressure, cardiac arrhythmias, atherosclerosis, and thrombosis. The two potential mechanisms are oxidative stress and systemic inflammation. Prenatal exposure has also been linked with cardiovascular outcomes later in life. Moreover, we also mentioned the epidemiological studies that strongly associate PM with CVD.