Laboratoire de Toxicologie, Pharmacologie et Signalisation Cellulaire, INSERM S-1124, Université Paris-Descartes, Centre Universitaire des Saints-Pères, 45 Rue des Saints-Pères, F-75270, Paris, Cedex 06, France.
Laboratory for Vascular Translational Science (LVTS), INSERM U1148, X. Bichat Hospital, Université Paris 13, UFR SMBH Sorbonne Paris Cité, 75018, Paris, France.
Sci Rep. 2017 Jul 5;7(1):4728. doi: 10.1038/s41598-017-04654-0.
Humans are exposed to multiple exogenous environmental pollutants. Many of these compounds are parts of mixtures that can exacerbate harmful effects of the individual mixture components. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is primarily produced via industrial processes including incineration and the manufacture of herbicides. Both endosulfan and TCDD are persistent organic pollutants which elicit cytotoxic effects by inducing reactive oxygen species generation. Sublethal concentrations of mixtures of TCDD and endosulfan increase oxidative stress, as well as mitochondrial homeostasis disruption, which is preceded by a calcium rise and, in fine, induce cell death. TCDD+Endosulfan elicit a complex signaling sequence involving reticulum endoplasmic destalilization which leads to Ca rise, superoxide anion production, ATP drop and late NADP(H) depletion associated with a mitochondrial induced apoptosis concomitant early autophagic processes. The ROS scavenger, N-acetyl-cysteine, blocks both the mixture-induced autophagy and death. Calcium chelators act similarly and mitochondrially targeted anti-oxidants also abrogate these effects. Inhibition of the autophagic fluxes with 3-methyladenine, increases mixture-induced cell death. These findings show that subchronic doses of pollutants may act synergistically. They also reveal that the onset of autophagy might serve as a protective mechanism against ROS-triggered cytotoxic effects of a cocktail of pollutants in Caco-2 cells and increase their tumorigenicity.
人类暴露于多种外源性环境污染物中。这些化合物中的许多是混合物的组成部分,会加剧个别混合物成分的有害影响。2,3,7,8-四氯二苯并对二恶英(TCDD)主要通过工业过程产生,包括焚烧和除草剂的制造。硫丹和 TCDD 都是持久性有机污染物,通过诱导活性氧物种的产生来产生细胞毒性作用。TCDD 和硫丹混合物的亚致死浓度会增加氧化应激和线粒体稳态破坏,这是由钙上升引起的,最终导致细胞死亡。TCDD+硫丹引发涉及内质网去稳定化的复杂信号序列,导致钙上升、超氧阴离子产生、ATP 下降和晚期 NADP(H)耗竭,同时伴随着线粒体诱导的凋亡和早期自噬过程。ROS 清除剂 N-乙酰半胱氨酸可阻断混合物诱导的自噬和死亡。钙螯合剂的作用类似,靶向线粒体的抗氧化剂也能消除这些作用。用 3-甲基腺嘌呤抑制自噬通量会增加混合物诱导的细胞死亡。这些发现表明,亚慢性剂量的污染物可能会协同作用。它们还表明,自噬的开始可能是一种针对污染物鸡尾酒引发的 ROS 触发的细胞毒性作用的保护机制,并增加它们的致瘤性。