An Jing, Jiang Jingjing, Tang Waner, Zhong Yufang, Ren Guofa, Shang Yu, Yu Zhiqiang
Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
Ecotoxicol Environ Saf. 2023 Jun 22;262:115160. doi: 10.1016/j.ecoenv.2023.115160.
Triphenyl phosphate (TPHP) has been widely used as flame retardants and been detected with increasing frequency in environment. TPHP can transform into mono-hydroxylated phosphate (OH-TPHP) and diester diphenyl phosphate (DPHP) through biotransformation. So far, information on the cytotoxicity and molecular regulatory mechanisms of TPHP metabolites are still limit. This study investigated the adverse effects of TPHP, OH-TPHP, and DPHP in HepG2 cells in terms of cell proliferation, lactate dehydrogenase release, reactive oxygen species generation, and mitochondrial membrane potential. The transcriptomic changes were measured using RNA sequencing, and bioinformatics characteristics including biological functions, signal pathways and protein-protein interaction were analyzed to explore the potential molecular mechanisms. Results displayed that the order of cytotoxicity was OH-TPHP> TPHP> DPHP. The prioritized biological functions changes induced by TPHP and OH-TPHP were correlated with lipid metabolism. Significant lipid accumulation was observed as confirmed by increased total cholesterol and triglycerides contents, and enhanced oil red O staining. Enrichment of PPARα/γ and down-stream genes suggested the participation of PPARs signal pathway in lipid metabolism disorder. In addition, TPHP and OH-TPHP induced endoplasmic reticulum stress (ERS), which was further confirmed by the ERS inhibitor experiment. In general, TPHP and OH-TPHP had obvious cytotoxic effects in HepG2 cells. PPARs signal pathway and endoplasmic reticulum stress may be involved in the lipid metabolism disorder induced by TPHP and OH-TPHP.
磷酸三苯酯（TPHP）作为阻燃剂被广泛使用，并且在环境中的检测频率日益增加。TPHP可通过生物转化转变为单羟基化磷酸盐（OH-TPHP）和磷酸二苯酯（DPHP）。到目前为止，关于TPHP代谢物的细胞毒性和分子调控机制的信息仍然有限。本研究从细胞增殖、乳酸脱氢酶释放、活性氧生成和线粒体膜电位方面研究了TPHP、OH-TPHP和DPHP对HepG2细胞的不良影响。使用RNA测序测量转录组变化，并分析包括生物学功能、信号通路和蛋白质-蛋白质相互作用在内的生物信息学特征，以探索潜在的分子机制。结果显示，细胞毒性顺序为OH-TPHP>TPHP>DPHP。TPHP和OH-TPHP诱导的优先生物学功能变化与脂质代谢相关。总胆固醇和甘油三酯含量增加以及油红O染色增强证实观察到显著的脂质积累。PPARα/γ及其下游基因的富集表明PPARs信号通路参与脂质代谢紊乱。此外，TPHP和OH-TPHP诱导内质网应激（ERS），ERS抑制剂实验进一步证实了这一点。总体而言，TPHP和OH-TPHP在HepG2细胞中具有明显的细胞毒性作用。PPARs信号通路和内质网应激可能参与TPHP和OH-TPHP诱导的脂质代谢紊乱。
