P450酶介导的典型有机紫外线吸收剂代谢活化/解毒分析及分子机制研究

The effect of biological metabolism on toxicity of environmental contaminants is seriously ignored in many basic toxicological stuides. Since CYP450-mediated metabolism is indispensable for environmental risk assessment, studies on CYP450-mediated metabolic activation/detoxification should be further strengthened. Quantum mechanics calculations, molecular docking and molecular dynamics simultaion were intergrated to resolve two chief difficulties involved in the study of CYP450-mediated metabolism, including the identification of key individual CYP450 enzymes and the prediction of site of metabolism. Two kind of emerging contaminants, benzotriazole UV stabilizers (BZTs) and benzophenone UV filters (BPs) were choosed for metabolic investigation. The human CYP450 enzymes critical to the metabolism of BZTs and BPs were identified and their metabolic activation/detoxification was investigated based on transfected HepG2 cell-based assay. The mechanism-based prediction of site of metabolism and in vitro metabolic assay were combined to further identifiy the metabolites and corresponding molecular structures. Our project may shed light on the molecular mechanism of CYP450-mediated metabolism of BPs and BZTs, which may also provide the guidance for studies of metabolic toxicity of remaining environmental contaminants.

许多针对环境污染物的常规毒性测试严重忽略了生物代谢对毒性的影响，而基于CYP450酶介导的代谢是环境风险评估中不可缺失的一环，因此亟需加强CYP450酶介导的环境污染物代谢活化/解毒研究。本项目将整合量子化学计算、分子对接和分子动力学模拟等方法去尝试解决CYP450代谢研究所面临的关键代谢酶的鉴定以及污染物代谢位点预测两大关键难点，具体以新兴污染物苯并三氮唑类（Benzotriazole, BZTs）类和二苯甲酮（Benzophenone, BPs）典型有机紫外线吸收剂为研究对象，鉴定代谢BZTs和BPs的人CYP450酶，并采用HepG2细胞转染实验分析BZTs和BPs的代谢毒性，进一步采用基于机理的代谢位点预测方法和CYP450酶体外代谢实验分析BZTs和BPs的代谢产物及分子结构，以期从分子水平上诠释CYP450酶介导的代谢分子机制，为其他类环境污染物的代谢毒性评估提供方法借鉴。

苯并三氮唑类（Benzotriazoles, BZTs）和二苯甲酮类（Benzophenones, BPs）这两类紫外线吸收剂全球使用量逐年增大，在环境中的残留持续增多，对人体健康以及生态环境具有潜在的危害。本项目选取了多种典型的BZTs和BPs，表征了其与人CYP450酶的相互作用；构建了人CYP450酶介导BZTs和BPs代谢位点预测和高分辨质谱Q-TOF/核磁共振NMR产物结构鉴定方法；明晰了CYP450酶代谢BZTs和BPs毒性变化趋势；阐明了BZTs和BPs对人CYP酶活性、HepG2细胞内mRNA水平和蛋白表达的影响；发现了BZTs和BPs干扰CYP酶的正常代谢过程，强调了代谢评估对新兴污染物健康评估的重要性，这为其他类环境污染物的代谢毒性研究在研究方法方面起重要借鉴作用。本项目已发表SCI收录论文15篇（其中2篇入选环境/生态学ESI 1%高被引论文），国际会议学术报告2次，国内会议学术报告7次。