Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People's Republic of China, 400715.
Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People's Republic of China, 400715.
Free Radic Biol Med. 2015 Dec;89:522-32. doi: 10.1016/j.freeradbiomed.2015.08.023. Epub 2015 Oct 8.
Fulminant hepatic failure (FHF) is a lethal clinical syndrome characterized by the activation of macrophages and the increased production of inflammatory mediators. The purpose of this study was to investigate the effects of neohesperidin dihydrochalcone (NHDC), a widely-used low caloric artificial sweetener against FHF. An FHF experimental model was established in mice by intraperitoneal injection of D-galactosamine (d-GalN) (400mg/kg)/lipopolysaccharides (LPS) (10 μg/kg). Mice were orally administered NHDC for 6 continuous days and at 1h before d-GalN/LPS administration. RAW264.7 macrophages were used as an in vitro model. Cells were pre-treated with NHDC for 1h before stimulation with LPS (10 μg/ml) for 6h. d-GalN/LPS markedly increased the serum transaminase activities and levels of oxidative and inflammatory markers, which were significantly attenuated by NHDC. Mechanistic analysis indicated that NHDC inhibited LPS-induced myeloid differentiation factor 88 (MyD88) and TIR-containing adapter molecule (TRIF)-dependent signaling. Transient transfection of TLR4 or MyD88 siRNA inhibited the downstream inflammatory signaling. This effect could also be achieved by the pretreatment with NHDC. The fluorescence microscopy and flow cytometry results suggested that NHDC potently inhibited the binding of LPS to TLR4 in RAW264.7 macrophages. In addition, the inhibitory effect of NHDC on LPS-induced translocation of TLR4 into lipid raft domains played an important role in the amelioration of production of downstream pro-inflammatory molecules. Furthermore, the activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) by NHDC inhibited TLR4 signaling. In conclusion, our results suggest that NHDC attenuates d-GalN/LPS-induced FHF by inhibiting the TLR4-mediated inflammatory pathway, demonstrating a new application of NHDC as a hepatoprotective agent.
暴发性肝衰竭(FHF)是一种致命的临床综合征,其特征在于巨噬细胞的激活和炎症介质的增加产生。本研究旨在研究新橙皮苷二氢查尔酮(NHDC),一种广泛用于低热量人工甜味剂对 FHF 的影响。通过腹腔注射 D-半乳糖胺(d-GalN)(400mg/kg)/脂多糖(LPS)(10μg/kg)在小鼠中建立 FHF 实验模型。小鼠连续口服 NHDC 6 天,并在 d-GalN/LPS 给药前 1 小时给药。RAW264.7 巨噬细胞作为体外模型。细胞用 LPS(10μg/ml)刺激前用 NHDC 预处理 1h,共 6h。d-GalN/LPS 显著增加血清转氨酶活性和氧化应激及炎症标志物水平,这些水平被 NHDC 显著减弱。机制分析表明,NHDC 抑制 LPS 诱导的髓样分化因子 88(MyD88)和 TIR 包含衔接分子(TRIF)依赖性信号转导。TLR4 或 MyD88 siRNA 的瞬时转染抑制下游炎症信号转导。NHDC 的预处理也能达到这种效果。荧光显微镜和流式细胞术结果表明,NHDC 能有效抑制 LPS 与 RAW264.7 巨噬细胞中 TLR4 的结合。此外,NHDC 对 LPS 诱导 TLR4 向脂筏区易位的抑制作用在改善下游促炎分子的产生中起着重要作用。此外,NHDC 通过激活核因子(红系衍生 2)样 2(Nrf2)抑制 TLR4 信号转导。总之,我们的研究结果表明,NHDC 通过抑制 TLR4 介导的炎症通路减轻 d-GalN/LPS 诱导的 FHF,表明 NHDC 作为一种肝保护剂的新应用。