Wildfire Smoke-Induced MicroRNA Changes in Mouse Plasma Extracellular Vesicles

These analyses set out to evaluate changes in microRNA signatures in the mouse plasma in response to simulated wildland fire exposure conditions. These exposure conditions were based on smoke condensate consisting of particulate matter and semivolative organic compounds resulting from the burning of two biomass fuels; namely , peat and red oak. These biomasses were evaluated under two burn conditions: flaming and smoldering. Saline exposures were also carried out as negative controls. Biological responses resulting from these exposures have been previously evaluated using an in vivo model (CD-1 mice) and an Ames mutagenicity assay (Kim et al. 2018, PMID: 29373863). For the in vivo evaluation, female mice were exposed to biomass smoke condensate samples using 50 uL saline containing 2 mg/mL PM administered to the lungs by oropharyngeal aspiration. Samples were collected at 4- and 24 h post-exposure. Mouse lung toxicity response data included alterations in immune cell populations, including neutrophil and macrophage counts, as well as protein markers of inflammation and tissue damage. The in vivo toxicity responses associated with each biomass burn condition were evaluated on the basis of equal mass as well as emission factors derived from the amount of biomass fuel consumed. Here, we expanded upon this important study by integrating toxicity responses, including newly generated microRNA signatures from extracellular vesicles isolated from select plasma samples.