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

水生环境的化学污染往往与环境应激因子相结合，并遵循复杂的时空模式。与中性有机化学品不同，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解离的化学品）的吸收和作用的影响知之甚少。超过一半的工业化学品和大约85%的药品是国际石油公司。因此，在前所未有的环境变化时代，了解控制这些影响的机制对于充分评估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的可用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、生化和生理过程的相互作用。我们将采用结合生物、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、可渗透物种的比例来测试理化参数对IOCs有效性和吸收的直接影响（目的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。将研究城市废水出水中发现的单个ioc的浓度、ioc的混合物和具有代表性的城市污水的浓度。化学分析将辅以基因表达分析（qPCR, RNAseq），以确定环境因素对ioc吸收和作用的影响。为了测试带电物种的主动转运和生物转化是否相关（目的2），我们将表征选定的环境因素对转运和生物转化蛋白的表达和活性的影响。最近，我们发现鱼鳃的屏障功能可以被病原体引起的炎症破坏。为了提高我们对炎症对mwes摄取ioc的影响的理解（目的3），我们将在暴露的鱼类中进行细菌脂多糖实验，以模拟病原体诱导的炎症。最后，将用主动转运、生物转化和上皮完整性的子模型对毒性动力学模型进行修正，以估计每个过程的个体贡献（目标4）。总的来说，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ioc的影响的机制理解，并将为制定水质准则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，并有助于在前所未有的全球变化时代为水威胁做好准备。

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.