Department of Toxicology and Sanitary Chemistry, School of Public Health, Tianjin Medical University, Tianjin, 300070, China; Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, 300070, China; National Demonstration Center for Experimental Preventive Medicine Education, Tianjin Medical University, Tianjin, 300070, China; Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin, 300070, China.
Department of Pharmacy, Tianjin Xiqing Hospital, Tianjin, 300000, China.
Environ Pollut. 2020 Aug;263(Pt A):114463. doi: 10.1016/j.envpol.2020.114463. Epub 2020 Apr 4.
PFASs are highly persistent in both natural and living environment, and pose a significant risk for wildlife and human beings. The present study was carried out to determine the inhibitory behaviours of fourteen PFASs on metabolic activity of two major isoforms of carboxylesterases (CES). The probe substrates 2-(2-benzoyl-3-methoxyphenyl) benzothiazole (BMBT) for CES1 and fluorescein diacetate (FD) for CES2 were utilized to determine the inhibitory potentials of PFASs on CES in vitro. The results demonstrated that perfluorododecanoic acid (PFDoA), perfluorotetradecanoic acid (PFTA) and perfluorooctadecanoic acid (PFOcDA) strongly inhibited CES1 and CES2. The half inhibition concentration (IC) value of PFDoA, PFTA and PFOcDA for CES1 inhibition was 10.6 μM, 13.4 μM and 12.6 μM, respectively. The IC for the inhibition of PFDoA, PFTA and PFOcDA towards CES2 were calculated to be 9.56 μM, 17.2 μM and 8.73 μM, respectively. PFDoA, PFTA and PFOcDA exhibited noncompetitive inhibition towards both CES1 and CES2. The inhibition kinetics parameters (K) were 27.7 μM, 26.9 μM, 11.9 μM, 4.04 μM, 29.1 μM, 27.4 μM for PFDoA-CES1, PFTA-CES1, PFOcDA-CES1, PFDoA-CES2, PFTA-CES2, PFOcDA-CES2, respectively. In vitro-in vivo extrapolation (IVIVE) predicted that when the plasma concentrations of PFDoA, PFTA and PFOcDA were greater than 2.77 μM, 2.69 μM and 1.19 μM, respectively, it might interfere with the metabolic reaction catalyzed by CES1 in vivo; when the plasma concentrations of PFDoA, PFTA and PFOcDA were greater than 0.40 μM, 2.91 μM, 2.74 μM, it might interfere with the metabolic reaction catalyzed by CES2 in vivo. Molecular docking was used to explore the interactions between PFASs and CES. In conclusion, PFASs were found to cause inhibitory effects on CES in vitro, and this finding would provide an important experimental basis for further in vivo testing of PFASs focused on CES inhibition endpoints.
全氟辛烷磺酸（PFASs）在自然和生活环境中高度持久存在，对野生动物和人类构成重大风险。本研究旨在确定 14 种 PFASs 对两种主要羧酸酯酶（CES）同工酶代谢活性的抑制作用。利用 2-（2-苯甲酰-3-甲氧基苯基）苯并噻唑（BMBT）作为 CES1 的探针底物和荧光素二乙酸酯（FD）作为 CES2 的探针底物，在体外测定 PFASs 对 CES 的抑制潜力。结果表明，全氟十二烷酸（PFDoA）、全氟十四烷酸（PFTA）和全氟十八烷酸（PFOcDA）强烈抑制 CES1 和 CES2。PFDoA、PFTA 和 PFOcDA 对 CES1 抑制的半抑制浓度（IC）值分别为 10.6μM、13.4μM 和 12.6μM。计算出 PFDoA、PFTA 和 PFOcDA 对 CES2 的抑制 IC 分别为 9.56μM、17.2μM 和 8.73μM。PFDoA、PFTA 和 PFOcDA 对 CES1 和 CES2 均表现出非竞争性抑制作用。抑制动力学参数（K）分别为 27.7μM、26.9μM、11.9μM、4.04μM、29.1μM、27.4μM 用于 PFDoA-CES1、PFTA-CES1、PFOcDA-CES1、PFDoA-CES2、PFTA-CES2、PFOcDA-CES2。体外-体内外推（IVIVE）预测，当 PFDoA、PFTA 和 PFOcDA 的血浆浓度分别大于 2.77μM、2.69μM 和 1.19μM 时，可能会干扰 CES1 在体内的代谢反应；当 PFDoA、PFTA 和 PFOcDA 的血浆浓度分别大于 0.40μM、2.91μM、2.74μM 时，可能会干扰 CES2 在体内的代谢反应。分子对接用于探索 PFASs 与 CES 之间的相互作用。总之，PFASs 被发现对 CES 具有体外抑制作用，这一发现为进一步研究以 CES 抑制终点为重点的 PFASs 体内试验提供了重要的实验依据。
