Yu Dongwei, Hales Barbara F, Robaire Bernard
Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada.
Department of Obstetrics and Gynecology, McGill University, Montreal, QC, H3G 1Y6, Canada.
Arch Toxicol. 2025 Sep 2. doi: 10.1007/s00204-025-04173-2.
Organophosphate esters (OPEs), commonly used as flame retardants and plasticizers, are ubiquitous environmental contaminants, with high concentrations found in indoor house dust. Previously, we have reported that individual OPEs have adverse effects on HepG2 liver cells. However, real-world exposure involves mixtures of OPEs. In this study, we investigated the effects of an environmentally relevant mixture of OPEs, detected in Canadian house dust, on HepG2 cell phenotype and function. Using high-content imaging, we found that this mixture increased cytotoxicity and lipid droplet size, while lysosomes were the most effected endpoint. We used the DQ-BSA degradation assay to assess the function of lysosomes and confocal microscopy to confirm the status of lysosomal transcription factor EB (TFEB). We then tested lysosomal enzyme activities to determine potential downstream effects. OPE mixture induced concentration-dependent increases in the degradation capacity of lysosomes and elevated nuclear translocation of TFEB when compared to controls. Increased activities of downstream lysosomal acid lipase (LAL) and cathepsin B (CTSB) validated the activation of TFEB and its downstream effect of lysosome biogenesis. Together, these data demonstrate that exposure to an environmentally relevant OPE mixture adversely affects liver cell survival, phenotype, and lysosome functions, providing potential mechanistic insight into consequences of OPE exposure and increased risk of liver damage associated with disrupted lipid and lysosome homeostasis. This study also highlights the importance of evaluating real-world chemical exposures as mixtures rather than as individual compounds.
有机磷酸酯(OPEs)常用作阻燃剂和增塑剂,是普遍存在的环境污染物,在室内灰尘中浓度很高。此前,我们报道过单个OPEs对HepG2肝细胞有不良影响。然而,实际环境中的接触涉及多种OPEs的混合物。在本研究中,我们调查了在加拿大房屋灰尘中检测到的与环境相关的OPEs混合物对HepG2细胞表型和功能的影响。通过高内涵成像,我们发现这种混合物增加了细胞毒性和脂滴大小,而溶酶体是受影响最严重的终点。我们使用DQ-牛血清白蛋白降解试验评估溶酶体的功能,并用共聚焦显微镜确认溶酶体转录因子EB(TFEB)的状态。然后我们检测了溶酶体酶活性以确定潜在的下游效应。与对照组相比,OPEs混合物诱导溶酶体降解能力呈浓度依赖性增加,并使TFEB的核转位升高。下游溶酶体酸性脂肪酶(LAL)和组织蛋白酶B(CTSB)活性的增加证实了TFEB的激活及其对溶酶体生物发生的下游效应。总之,这些数据表明,接触与环境相关的OPEs混合物会对肝细胞存活、表型和溶酶体功能产生不利影响,为OPEs暴露的后果以及与脂质和溶酶体稳态破坏相关的肝损伤风险增加提供了潜在的机制性见解。本研究还强调了将实际环境中的化学物质暴露作为混合物而非单个化合物进行评估的重要性。