Exposure to Dimethyl Selenide (DMSe)-Derived Secondary Organic Aerosol Alters Transcriptomic Profiles in Human Airway Epithelial Cells

Abstract

Dimethyl selenide (DMSe) is one of the major volatile organoselenium compounds released from aquatic and terrestrial environments through microbial transformation and plant metabolism. The detailed processes of DMSe leading to secondary organic aerosol (SOA) formation and the pulmonary health effects induced by inhalation of DMSe-derived SOA remain largely unknown. In this study, we characterized the chemical composition and formation yields of SOA produced from the oxidation of DMSe with OH radicals and O3 in controlled chamber experiments. Further, we profiled the transcriptome-wide gene expression changes in human airway epithelial cells (BEAS-2B) after exposure to DMSe-derived SOA. Our analyses indicated a significantly higher SOA yield resulting from the OH-initiated oxidation of DMSe. The oxidative potential of DMSe-derived SOA, as measured by the dithiothreitol (DTT) assay, suggested the presence of oxidizing moieties in DMSe-derived SOA at levels higher than typical ambient aerosols. Utilizing RNA sequencing (RNA-Seq) techniques, gene expression profiling followed by pathway enrichment analysis revealed several major biological pathways perturbed by DMSe-derived SOA, including elevated genotoxicity, DNA damage, and p53-mediated stress responses, as well as downregulated cholesterol biosynthesis, glycolysis, and interleukin IL-4/IL-13 signaling. This study highlights the significance of DMSe-derived SOA as a stressor in human airway epithelial cells.

Variations and Sources of Organic Aerosol in Winter Beijing under Markedly Reduced Anthropogenic Activities During COVID-2019

“… 27 − 29 SOA can greatly impact atmospheric radiation balance and human health. 30 − 36 Therefore, it is of significance to study the OA emission and aging. A recent study reported that the proportion of SOA in total OA increased to more than 90% during the lockdown in Beijing, 1 which was probably promoted by NO x reduction, change of meteorological condition, and heterogeneous chemistry.…”

Lung Inflammatory Response to Environmental Dust Exposure in Mice Suggests a Link to Regional Respiratory Disease Risk

“…Through microbial transformation in the soil, Se can be removed and expelled into the atmosphere as Dimethyl selenide (DMSe), and secondary organic aerosols derived from DMSe oxidation were recently found to increase IL-6 release and upregulate HOX-1, TNF-α , and IL-6 in the BEAS-2B bronchial epithelial cell line. 12 Previous studies have also confirmed the presence of diatoms (a major group of microalgae), cyanobacteria, and fungi in the Salton Sea. These biological species can typically be found in marine settings and are all capable of releasing a variety of proteins, including proteases.…”

Crisis at the Salton Sea: Research Gaps and Opportunities

“…Methylated selenium species are volatile and can enter the atmosphere. Once in the air, this compound oxidizes and forms secondary PM, which was demonstrated in a recent laboratory-based study (Ahmed et al, 2019). Secondary selenium aerosol components have not been directly measured in the PM collected around Salton Sea.…”

“…The relatively high EF of Se in PM samples, however, as well as the more uniform distribution of Se on submicron PM, suggests that Se on PM is likely derived from oxidation of DMSe and the resulting products containing Se. Unlike sulfate, DMSe-derived oxidation products forming secondary PM may lead to elevated toxicity linked to oxidative DNA damage and a negative immune system response to airway inflammation in human epithelial lung cells (Ahmed et al, 2019). It is unknown how concentrations of H2S, DMS, and DMSe in the water and air or the concentration of their oxidation products in PM will evolve due to changes in the biological activities and physical conditions of the water column under future scenarios.…”