Effect of air pollutants on allergic inflammation in structural cells of nasal mucosa.

Abstract

Air pollution is a growing global concern, and its effect on allergic inflammation has attracted the attention of many researchers. Particulate matter (PM) is a major component of ambient air pollution, and heavy metals are the primary toxic constituents of PM. As previous studies on the impact of air pollutants on allergic inflammation lacked physiological resemblance to actual atmospheric exposure, we built an experimental model to investigate the effects of aerosolized air pollutants on nasal epithelial cells and fibroblasts. We collected PM 2.5 samples from ambient 24 h air in Seoul from August 2020 to August 2022, and then conducted component analysis for metallic constituents. Primary nasal epithelial cells and nasal fibroblasts, obtained and cultured from the turbinate tissues of human participants, were treated with PM 2.5 and heavy metals were identified from component analysis to observe changes in cytokine expression. 3D-hybrid culture model, a co-culture of an air-liquid interface and nasal fibroblast spheroids, was built to observe the impact of air pollutants in the form of aerosols. Among the heavy metals, Si was the predominant component of PM 2.5 and Zn showed the highest correlation with the concentration of PM 2.5 in Seoul. PM 2.5, Zn, and Si increased the production of epithelial cell-derived cytokines, with which PM 2.5 and Zn exhibited similar trends with one another. Exposure of 3D-hybrid model to aerosolized PM 2.5 and Zn yielded elevated periostin, α-SMA, and fibronectin expressions from fibroblast spheroids, and those without epithelial barrier exhibited a similar increase in periostin expression. Ambient air pollutants in the form of aerosols lead to an increased expression of allergic inflammatory cytokines in both nasal epithelial cells and fibroblasts. Regulations on air pollution will help reduce the burden of allergic diseases worldwide in the future.