Understanding the impacts of environmental factors on uptake and effects of ionizable organic chemicals in aquatic organisms

水环境的化学污染往往与遵循复杂时空模式的环境应激源相结合。与中性有机化学品不同，环境因素对可电离有机化学品(IOCs)吸收和影响的影响知之甚少。可电离有机化学品是指根据环境条件完全或部分解离的化学品。超过一半的工业化学品和大约85%的药品是IOC。因此，在一个前所未有的环境变化时代，对控制这些影响的机制的了解对于充分评估海委会对水生生态系统的风险至关重要。这项拟议研究的总体目标是确定控制IOCs有效性的环境因素，从而控制IOCs的影响，以及它们与水生生物，特别是鱼类的分子、生化和生理过程的相互作用。我们将使用结合生物、化学和计算技术的综合方法来实现这一目标。为了通过控制不带电荷的可渗透物种的比例来测试物理化学参数对IOCs的利用率和摄取的直接影响(目标1)，我们将使用鳃细胞进行体外渗透实验，并用虹鲑鱼进行体内实验。将研究在城市污水流出物(MWWE)、IOCs混合物和具有代表性的MWWE中发现的单个IOCs的浓度。化学分析将得到基因表达分析(qPCR、RNAseq)的补充，以确定环境因素对IOCs摄取和影响的影响。为了测试带电物种的主动运输和生物转化是否是相关的过程(目标2)，我们将表征选定的环境因素对运输和生物转化蛋白的表达和活性的影响。最近，我们发现病原体诱导的炎症可以破坏鱼鳃的屏障功能。为了更好地了解炎症对MWWE摄取IOCs的影响(目标3)，我们将进行细菌脂多糖实验，以模拟暴露在鱼中的病原体诱导的炎症。最后，将用主动转运、生物转化和上皮完整性的子模型来修正毒物动力学模型，以估计每个过程的个体贡献(目标4)。总体而言，这项创新和综合研究将从机械上理解环境因素对IOCs在水生生物中的吸收和影响的影响，并将为制定水质指南以保护水生生态系统健康的监管机构提供信息。这将有助于解决地表水污染这一关键环境问题，并有助于在一个前所未有的全球变化时代为应对水威胁做好准备。

Chemical contamination of the aquatic environment often occurs in combination with environmental stressors that follow complex spatiotemporal patterns. Unlike for neutral organic chemicals, the impacts of environmental factors on uptake and effects of ionizable organic chemicals (IOCs), i.e. chemicals that are fully or partially dissociated depending on ambient conditions, are poorly understood. More than half of all industrial chemicals, and approximately 85% of pharmaceuticals are IOCs. Consequently, knowledge of the mechanisms that govern these impacts is critical to adequately assess the risks of IOCs to aquatic ecosystems in an era of unprecedented environmental change. The overall goal of this proposed research is to identify environmental factors that control the availability and consequently the effects of IOCs, and their interactions with molecular, biochemical and physiological processes in aquatic organisms, specifically fish. We will use an integrative approach combining biological, chemical and computational techniques to achieve this goal. To test the direct influence of physicochemical parameters on the availability and uptake of IOCs by controlling the fraction of uncharged, permeable species (Objective 1), we will perform in vitro permeation experiments using gill cells, and in vivo experiments with rainbow trout. Concentrations of individual IOCs found in municipal waste water effluents (MWWEs), mixtures of IOCs, and representative MWWEs will be studied. Chemical analyses will be complemented by gene expression analyses (qPCR, RNAseq) to determine the impacts of environmental factors on uptake and effects of IOCs. To test whether active transport and biotransformation of charged species are relevant processes (Objective 2), we will characterize the effects of selected environmental factors on the expression and activity of transport and biotransformation proteins. Recently, we discovered that the barrier function of the fish gill can be disrupted by pathogen-induced inflammation. To improve our understanding of the effects of inflammation on the uptake of IOCs from MWWEs (Objective 3), we will conduct experiments with bacterial lipopolysaccharides to mimic pathogen-induced inflammation in exposed fish. Finally, a toxicokinetic model will be amended with sub-models for active transport, biotransformation, and epithelial integrity to estimate the individual contribution of each of these processes (Objective 4). Overall, this innovative and integrated research will result in a mechanistic understanding of the impacts of environmental factors on uptake and effects of IOCs in aquatic organisms and will inform regulators that develop water quality guidelines to protect aquatic ecosystem health. This will facilitate solving the key environmental issue of surface water contamination and help to prepare for water threats in an era of unprecedented global change.