The sea urchin larval response to metaloxide nanoparticule exposure

Engineered nanoparticles (ENPs) are increasingly used to generate innovative industrial and medical goods. Because of their broad applications, they form a new class of pollutants with potential eco-toxicological impacts on marine ecosystems. Attempting to evaluate the risk, we investigated the toxicity of Iron and Zinc oxide ENPs on Paracentrotus lividus sea urchin embryos. Sea urchin embryos are sensitive to both ENPs with a much stronger impact of ZnO ENPs. Transcriptome-wide analyses were conducted after exposure to ENPs or the corresponding ions. Only a very limited number of genes are differentially expressed in response to Fe2O3 ENPs or FeCl3. In contrast, both ZnO ENPs and ZnSO4 caused alteration of biological processes with stronger perturbation of gene expression for the ionic form (higher LFC). Comparison of GO term enrichment of the differentially expressed genes indicated that ENP and ions elicited partly different mechanisms, suggesting that a nanoparticule-dependent response was induced. Remarkably, the expression of the metal binding and ROS scavenging Metallothioneins were massively induced by ZnO ENPs and ZnSO4 while ZnO ENPs and ions mainly repressed the transcription regulation processes which control embryo development. Overall design: mRNA profiles of 24h post-fertilization control or treated embryos were generated by deep sequencing, using Illumina HiSeq 2500

工程化纳米颗粒（engineered nanoparticles, ENPs）正日益被用于研发创新型工业与医疗产品。由于其应用范围广泛，这类颗粒已成为一类新型污染物，对海洋生态系统存在潜在的生态毒理学影响。为评估其风险，本研究探究了氧化铁与氧化锌工程化纳米颗粒对丽花海胆（Paracentrotus lividus）胚胎的毒性效应。丽花海胆胚胎对两类纳米颗粒均敏感，其中氧化锌纳米颗粒的毒性效应更为显著。研究人员对暴露于纳米颗粒或其对应离子的样本开展了全转录组分析。相较于三氧化二铁（Fe₂O₃）纳米颗粒与氯化铁（FeCl₃）处理组，仅极少量基因出现差异表达。与之相反，氧化锌纳米颗粒与硫酸锌（ZnSO₄）处理组均引发了生物学过程的紊乱，且离子形态对基因表达的扰动更强（对数折叠变化值更高，LFC）。对差异表达基因的基因本体（Gene Ontology, GO）功能富集分析结果显示，纳米颗粒与对应离子所引发的分子机制存在部分差异，表明存在依赖于纳米颗粒本身的应答反应。值得注意的是，氧化锌纳米颗粒与硫酸锌均可大量诱导金属结合与活性氧（reactive oxygen species, ROS）清除相关的金属硫蛋白（Metallothioneins）的表达；而氧化锌纳米颗粒及其对应离子则主要抑制了调控胚胎发育的转录调控过程。实验整体设计：本研究采用Illumina HiSeq 2500测序平台，对受精后24小时的对照组与处理组海胆胚胎的mRNA转录组进行了深度测序。