Cytotoxicity analysis of ambient fine particle in BEAS-2B cells on an air-liquid interface (ALI) microfluidics system.

Abstract

Ambient fine particle is a crucial indicator of air pollution brought into the air by sundry natural and public events. However, a comprehensive understanding of the PM2.5-induced cytotoxicity especially the contribution of bioaerosol part is still undiscovered. Herein, an ALI microfluidics system integrated multi-omics (iTRAQ & RNA-seq) was successfully utilized to recognize the molecular mechanisms induced by microorganisms carried bioaerosol in human lung epithelial cells. The cells viability was above 98% within 21\u202fdays on this system. Moreover, the results showed that eight microorganisms-related pathways (e.g., Salmonella, amoebiasis, HTLV-1) were activated after exposure to PM2.5 for 24\u202fh, which played a certain proportion in contributing to inflammation reaction. In addition, multi-omics demonstrated that three inflammation-related signal transduction cascades including MAPK signaling pathway, TNF signaling pathway, and TGF signaling pathway were triggered by fine particles, ultimately leading to apoptosis-related process disorder by associated cytokines like TNF, IL6, and TGF-β. Furthermore, flow cytometry analysis showed that the cell apoptosis rate increased from 3.8% to 66.7% between the cells exposed to PM2.5 (10\u202fμg/cm2) for 24\u202fh and untreated control cells, which indicated that the fine particles had the ability to activate apoptosis-related signal cascades and result in apoptosis. ELISA assay and western blot indicated that HO-1, JNK, IL6, TNF, NF-κB, and FGF14 were significantly increased after exposure to PM2.5 while Casp3 and FGFR were decreased, which were consistent with the multi-omics. Moreover, PM2.5 components (OC, EC, 16PAHs, As, Cu, Mn, Cl-, and NO3-) were significantly correlated to the inflammation related proteins and cytokines, which played a vital role in the inflammation and apoptosis related signaling pathways. These findings pointed to strong links among microorganisms infection, inflammation, and apoptosis in cell response to PM2.5 carried microorganisms. It also provided a new approach for understanding PM2.5-induced cytotoxicity and health risks.