Primary cell cultures from deceased harbor porpoises to study effects of polystyrene nanoplastics on gene expression

Micro- and Nanoplastic particles (MNPs) are abundantly present in the environment including in our oceans. Whale species (cetaceans) occupy the top of the food chain and get exposed to MNPs via their diet. Therefor cetaceans are considered sentinel species to investigate health effects of MNPs in mammals. The aim of this study is to understand how these particles affect cellular function of marine mammals. For this harbor porpoise tissues were isolated post mortem and cells were cultured in vitro. Cells were subsequently exposed to fluorescently-labelled polystyrene MNPs of 1000, 200, and 50 nm diameter. After exposure the cells were examined by confocal laser scanning microscopy and RNA sequencing. Plastic particles, even of 1000 nm diameter were observed inside the cells after 24 h of exposure. Gene expression changes were observed after plastic particle exposure in pathways of various biological processes including signaling and metabolism. In conclusion, this study shows that exposure to MNPs induces cellular responses and changes in gene expression in fibroblast-like cells from a sentinel marine mammal. Comparative analyses between human, cetacean and fish show common as well as species-specific gene responses which could be relevant to further study the health impact of MNPs.