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压力因素结合发生。与中性有机化学品不同，人们对环境因素对可电离有机化学品（即根据环境条件完全或部分离解的化学品）的吸收和影响的影响知之甚少。超过一半的工业化学品和大约85%的药品都是IOC。因此，了解控制这些影响的机制对于在前所未有的环境变化时代充分评估IOC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IOC的可得性及其影响的环境因素，以及它们与水生生物特别是鱼类的分子、生物化学和生理过程的相互作用。我们将使用一种综合的方法，结合生物，化学和计算技术来实现这一目标。为了通过控制不带电的渗透性物质的分数来测试理化参数对IOC的可用性和摄取的直接影响（目标1），我们将使用鳃细胞进行体外渗透实验，并使用虹鳟鱼进行体内实验。将研究城市废水流出物（MWWE）中发现的单个IOCs的浓度、IOCs的混合物以及代表性的MWWE。化学分析将辅之以基因表达分析（qPCR、RNAseq），以确定环境因素对国际化学品吸收和影响的影响。为了测试是否带电物种的主动运输和生物转化相关的过程（目标2），我们将描述所选的环境因素对运输和生物转化蛋白的表达和活性的影响。近年来，我们发现病原体引起的炎症可以破坏鱼鳃的屏障功能。为了提高我们对炎症对MWWE中IOCs摄取的影响的理解（目标3），我们将用细菌脂多糖进行实验，以模拟暴露鱼类中病原体诱导的炎症。最后，将使用主动转运、生物转化和上皮完整性的子模型修正毒代动力学模型，以估计这些过程中每一个的个体贡献（目标4）。总体而言，这项创新和综合研究将导致对环境因素对水生生物吸收和影响的影响的机械理解，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的关键环境问题，并有助于在一个前所未有的全球变化时代为应对水资源威胁做好准备。

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.