Carbon nanopowder acts as a Trojan-horse for benzo(α)pyrene in Danio rerio embryos

Carbon-based nanoparticles (CBNs) are largely distributed worldwide due to fossil fuel combustion and their presence in many consumer products. In addition to their proven toxicological effects in several biological models, attention in recent years has focussed on the role played by CBNs as Trojan-horse carriers for adsorbed environmental pollutants. This role has not been conclusively determined to date because CBNs can decrease the bioavailability of contaminants or represent an additional source of intake. Herein, we evaluated the intake, transport and distribution of one of the carbon-based powders, the so-called carbon nanopowder (CNPW), and benzo(α)pyrene, when administered alone and in co-exposure to Danio rerio embryos. Data obtained by means of advanced microscopic techniques illustrated that the “particle-specific” effect induced a modification in the accumulation of benzo(α)pyrene, which is forced to follow the distribution of the physical pollutant instead of its natural bioaccumulation. The combined results from functional proteomics and gene transcription analysis highlighted the different biochemical pathways involved in the action of the two different contaminants administered alone and when bound together. In particular, we observed a clear change in several proteins involved in the homeostatic response to hypoxia only after exposure to the CNPW or co-exposure to the mixture, whereas exposure to benzo(α)pyrene alone mainly modified structural proteins. The entire dataset suggested a Trojan-horse mechanism involved in the biological impacts on Danio rerio embryos especially due to different bioaccumulation pathways and cellular targets.

碳基纳米颗粒（Carbon-based nanoparticles, CBNs）因化石燃料燃烧而广泛分布于全球各地，且在诸多消费品中均有存在。除其在多种生物模型中已被证实的毒理学效应外，近年来的研究焦点还集中于碳基纳米颗粒作为吸附环境污染物的特洛伊木马载体所发挥的作用。迄今这一作用尚未得到确凿证实，因为碳基纳米颗粒既可能降低污染物的生物利用度，也可能构成额外的污染物摄入途径。

本研究针对一种碳基粉末——即碳纳米粉末（Carbon nanopowder, CNPW）——与苯并(α)芘（benzo(α)pyrene），分别以单独暴露及联合暴露的方式，评估了二者对斑马鱼（Danio rerio）胚胎的摄入、转运与分布情况。通过先进显微技术获取的数据显示，“颗粒特异性效应”改变了苯并(α)芘的蓄积模式，使其被迫跟随物理性污染物的分布路径，而非其自然生物蓄积途径。

功能蛋白质组学与基因转录分析的综合结果表明，两种污染物单独暴露与联合暴露时，其所涉及的生化通路存在差异。具体而言，仅在碳纳米粉末单独暴露或联合暴露实验组中，我们观测到参与缺氧稳态应答的多种蛋白质发生了显著变化；而单独暴露于苯并(α)芘时，主要改变的是结构蛋白质的表达。本研究的全部数据集提示，碳基纳米颗粒通过差异化的生物蓄积途径与细胞靶点，对斑马鱼胚胎产生了生物学影响，这一过程符合特洛伊木马机制。