State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing, Jiangsu 210023, P.R. China.
Department of Environmental Science, School of Engineering, China Pharmaceutical University, Nanjing, Jiangsu 211198, P.R. China.
Environ Sci Technol. 2020 Mar 17;54(6):3417-3427. doi: 10.1021/acs.est.9b06386. Epub 2020 Mar 5.
Microplastics (MPs) as widespread contamination pose a high risk for aquatic organisms. However, the current understanding of MP toxicity is based on cell population-averaged measurements. Our aim was to gain a comprehensive understanding of the size-dependent effects of polystyrene MPs (PS-MPs) on intestinal cell populations in zebrafish and characterize the interplay of MPs, intestinal cells, and intestinal microbiota. Here, we used single-cell RNA sequencing to determine the transcriptome heterogeneity of 12 000 intestinal cells obtained from zebrafish exposed to 100 nm, 5 μm, and 200 μm PS-MPs for 21 days. Eight intestinal cell populations were identified. Combined with changes in intestinal microbiota, our findings highlight a previously unrecognized end point that all three sizes of PS-MPs induced dysfunction of intestinal immune cells (including effects on phagosomes and the regulation of immune system processes) and increased the abundance of pathogenic bacteria. However, only 100 nm PS-MPs altered the expression of genes related to phagocyte-produced reactive oxygen species (ROS) generation and increased mucus secretion by secretory cells. Microsize PS-MPs specifically changed the lysosome (5 μm) and cell surface receptor signaling (200 μm) processes of the macrophages. Our findings pinpoint to cell-specific and size-dependent responses to PS-MPs in fish intestine, which can provide a reference for future study directions.
微塑料（MPs）作为广泛存在的污染物，对水生生物构成了高风险。然而，目前对 MPs 毒性的认识是基于细胞群体平均测量的。我们的目的是全面了解聚苯乙烯 MPs（PS-MPs）对斑马鱼肠道细胞群体的尺寸依赖性影响，并描述 MPs、肠道细胞和肠道微生物群之间的相互作用。在这里，我们使用单细胞 RNA 测序来确定暴露于 100nm、5μm 和 200μm PS-MPs 21 天后，从斑马鱼肠道中获得的 12000 个肠道细胞的转录组异质性。鉴定出了 8 种肠道细胞群体。结合肠道微生物群的变化，我们的研究结果突出了一个以前未被认识的终点，即所有三种尺寸的 PS-MPs 均诱导了肠道免疫细胞的功能障碍（包括对吞噬体的影响和免疫系统过程的调节），并增加了致病菌的丰度。然而，只有 100nm PS-MPs 改变了与吞噬细胞产生的活性氧（ROS）生成相关的基因表达，并增加了分泌细胞的粘液分泌。微尺寸 PS-MPs 特异性地改变了巨噬细胞的溶酶体（5μm）和细胞表面受体信号（200μm）过程。我们的研究结果确定了鱼类肠道中对 PS-MPs 的细胞特异性和尺寸依赖性反应，可为未来的研究方向提供参考。
