Liu Jieyu, Feng Rui, Wang Dan, Huo Taoguang, Jiang Hong
Department of Health Laboratory Technology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province, 110122, PR China.
Department of Health Laboratory Technology, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province, 110122, PR China.
Ecotoxicol Environ Saf. 2021 Aug 17;224:112664. doi: 10.1016/j.ecoenv.2021.112664.
Exposure to triclosan (TCS) has been implicated in neurotoxicity including autism spectrum disorders in vivo and oxidative stress and cell apoptosis in vitro. Thus, the molecular mechanisms underlying TCS-induced neurotoxicity warrants further research. In this study, we try to address the mode of action that TCS induced the expression of inflammatory cytokines by shifting metabolism to glycolysis. BV-2 cells were treated with 20 μM TCS for 24 h, and the conditional medium from TCS-induced activated microglia reduced the viability of the murine hippocampal neurons cell line HT22. Protein expression levels in the nuclear factor kappa B (NF-κB) signaling pathway were measured through Western blotting, and the expression levels of inflammatory cytokine were measured using quantitative real-time PCR. The results showed that exposure to TCS enhanced NF-κB activation, increased inflammatory cytokine expression including interleukin (IL) 1β, IL-6, and tumor necrosis factor (TNF) α in the BV-2 cells. The glucose consumption and lactate production in BV2 cell increased sharply after exposure to TCS for 24 h. Based on our qPCR and Western blotting results, the expression of the key glycolysis enzymes-namely hexokinase 1, pyruvate kinase M2, and lactate dehydrogenase A-increased after treatment with 20 μM TCS. Furthermore, inhibiting glycolysis by 2-deoxy-D-glucose reduced the activation of NF-κB and the mRNA expression of the inflammatory cytokines in the TCS-activated BV-2 microglia. The expression of the proteins of the Akt/mTOR/HIF1α pathway examined through Western blotting, which regulates glycolysis, also increased in the BV2 cells exposed to TCS. Moreover, Akt and mTOR inhibition by using LY294002 and rapamycin, respectively, blocked inflammatory cytokine overexpression induced by TCS. In conclusion, TCS can induce glycolysis and directly drive inflammatory activation in microglia; with the mediation of the Akt/mTOR/HIF1α pathway.
三氯生（TCS）暴露已被证明与神经毒性有关，包括体内的自闭症谱系障碍以及体外的氧化应激和细胞凋亡。因此，TCS诱导神经毒性的分子机制值得进一步研究。在本研究中，我们试图探讨TCS通过将代谢转变为糖酵解来诱导炎性细胞因子表达的作用模式。用20μM TCS处理BV-2细胞24小时，来自TCS诱导激活的小胶质细胞的条件培养基降低了小鼠海马神经元细胞系HT22的活力。通过蛋白质印迹法检测核因子κB（NF-κB）信号通路中的蛋白质表达水平，并使用定量实时PCR检测炎性细胞因子的表达水平。结果表明，暴露于TCS可增强BV-2细胞中NF-κB的激活，增加炎性细胞因子的表达，包括白细胞介素（IL）-1β、IL-6和肿瘤坏死因子（TNF）-α。暴露于TCS 24小时后，BV2细胞中的葡萄糖消耗和乳酸产生急剧增加。基于我们的qPCR和蛋白质印迹结果，在用20μM TCS处理后，关键糖酵解酶即己糖激酶1、丙酮酸激酶M2和乳酸脱氢酶A的表达增加。此外，用2-脱氧-D-葡萄糖抑制糖酵解可降低TCS激活的BV-2小胶质细胞中NF-κB的激活和炎性细胞因子的mRNA表达。通过蛋白质印迹法检测的调节糖酵解的Akt/mTOR/HIF1α通路的蛋白质表达在暴露于TCS的BV2细胞中也增加。此外，分别使用LY294002和雷帕霉素抑制Akt和mTOR可阻断TCS诱导的炎性细胞因子过表达。总之，TCS可诱导糖酵解并直接驱动小胶质细胞中的炎性激活；通过Akt/mTOR/HIF1α通路介导。
