Heterogeneity effects of nanoplastics and lead on zebrafish intestine identified by single-cell sequencing

Plastic particles in water environment can adsorb heavy metals, leading to combined toxicity to aquatic organisms. However, current conclusions are mostly obtained based on cell population-average responses. Heterogeneity effects among cell populations in aquatic organisms remain unclear. This study analyzed the heterogeneity effects of 200 μg/L 100 nm polystyrene nanoplastics (PS-NPs), 50 μg/L lead (Pb), and their combined exposures on zebrafish intestine cells by single-cell RNA sequencing.A total of 38640 cells in the zebrafish intestine was obtained and identified as seven cell populations, including enterocytes, macrophages, neutrophils, B cells, T cells, enteroendocrine cells, and goblet cells.Co-exposure of PS-NPs and Pb caused similar transcriptome profiles with PS-NPs exposure in macrophages, which changed immunological recognition processes. The Pb exposure influenced the macrophages by direct cytotoxicity. However, the Pb alone and combined exposures induced similar modes of action in the enterocytes, including the generation of oxidative stress and abnormal lipid metabolism. Single cell RNA sequencing were adopted to learn the transcriptional variation in zebrafish intestine followed exposure nanoplastics and lead.