Co-culture of human alveolar epithelial (A549) and macrophage (THP-1) cells to study the potential toxicity of ambient PM2.5: a comparison of growth under ALI and submerged conditions. Issue 5 (24th September 2020)

• Record Type: Journal Article
• Authors: Wang, Guanghe; Zhang, Xiaofeng; Liu, Xinyan; Zheng, Jing
• Is Part Of: Toxicology research. Volume 9:Issue 5(2020)
• Page Start: 636
• Page End: 651
• Publication Date: 2020-09-24
• Subjects: fine particulate matter (PM2.5) -- air–liquid interface (ALI) -- submerged culture -- co-culture model -- in vitro toxicity; Toxicology -- Periodicals; 615.9005
• DOI: 10.1093/toxres/tfaa072
• Languages: English
• ISSNs: 2045-452X

Abstract

Abstract: Fine particulate matter (PM2.5 ) in the ambient atmosphere is strongly associated with detrimental health effects. However, these particles from various sources and regions are unlikely equally toxic. While animal studies are impractical for high-throughput toxicity testing, appropriate in vitro models are urgently needed. Co-culture of A549 and THP-1 macrophages grown at air–liquid interface (ALI) or under submerged conditions was exposed to same concentrations of ambient PM2.5 to provide accurate comparisons between culture methods. Following 24-h incubation with PM2.5 collected in Harbin in China, biological endpoints being investigated include cytotoxicity, reactive oxygen species (ROS) levels and pro-inflammatory mediators. The co-culture grown under submerged condition demonstrated a significant increase in ROS levels and all tested pro-inflammatory indicators [interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor-α] in mRNA expression and released protein levels. Similar but a declining response trend was observed using the same PM2.5 incubation after grown at ALI. We further observed a significant increase of PM2.5 -induced phosphorylation of p38 MAPK and activation of NF-κB p65 in a dose-dependent trend for co-cultures grown under submerged condition. These results provide important implications that culture conditions (ALI versus submerged) can induce different extents of biological responses to ambient PM2.5 ; the co-culture grown at ALI is less likely to produce false-positive results than submerged culture. Hence, culture conditions should be discussed when comparing in vitro methods used for high-throughput PM2.5 toxicity assessment in future.