Nrf-2信号通路活化和枯否细胞极化调控在二烯丙基二硫（DADS）拮抗酒精性肝病中的作用

Alcoholic liver disease (ALD) has become a worldwide public health problem due to the high morbidity and the lack of effective therapeutic medicines. Previous studies have demonstrated that oxidative stress and gut-sourced lipopolysaccharide (LPS)-mediated M1 polarization of Kupffer cells (KCs) play critical roles in the pathogenesis of ALD. Thus, compounds with antioxidant and KCs polarization- modulating activities could theoretically protect against ALD and have the potential to be used for ALD treatment in future. Based on our previous studies, this project will focus on Nrf-2-mediated antioxidant pathway and the LPS-mediated KCs M1 polarization, and aims to investigate the effect of diallyl disulfide (DADS) on the activation of Nrf-2 pathway and the suppression of LPS-mediated KCs M1 polarization, and also try to explore the relationship between Nrf-2 activation and KCs polarization. After that, we will study the protection of DADS against acute and chronic ethanol-induced liver injury in mice, and explore the potential mechanisms. The results of the project will provide further information for mechanisms of ALD, and also provide scientific basis for the use of DADS in the prevention and treatment of ALD.

酒精性肝病（ALD）已成为不容忽视的全球性的公共卫生问题；其发病率在全球范围内居高不下，且缺乏安全有效的防治药物。研究证实，氧化应激和肠道来源的脂多糖（LPS）诱导枯否细胞（KCs）M1型极化是ALD发病的主要病因；因此兼具“抗氧化活性”和“调控KCs极化活性”的物质在理论上具有拮抗ALD的作用及潜在的临床应用前景。本项目拟在前期工作的基础上，以“Nrf-2调控的抗氧化通路”和“LPS诱导的KCs极化”为切入点，研究DADS对肝细胞Nrf-2通路的激活作用和对LPS诱导的KCsM1型极化的调控作用，并探讨DADS对KCs中Nrf-2通路的激活与其对KCs极化调控之间的关系。在此基础上，研究DADS对小鼠急性和慢性ALD的保护作用，并围绕“Nrf-2通路”和“KCs极化”进行分子机制探讨。本项目的研究成果将进一步揭示ALD的分子机制，并为DADS用于ALD的防治提供科学依据。

酒精性肝病（alcoholic liver disease, ALD）发病率不断攀升，临床上尚无有效的防治药物。我们前期研究发现二烯丙基二硫（diallyl disulfide, DADS）可能是大蒜中主要的具有拮抗ALD活性的物质。本项目聚焦DADS对肝脏巨噬细胞极化的调控及其与Nrf2通路活化的关系。研究发现：（1）DADS可显著抑制内毒素（lipopolysaccharide, LPS）诱导的小鼠RAW264.7巨噬细胞M1型极化，并抑制LPS引起的小鼠肝脏巨噬细胞极化；通过NRF2-/-RAW264.7细胞和NRF2-/-小鼠进一步证实DADS对LPS诱导巨噬细胞极化调控与NRF2激活密切相关。（2）DADS可明显减轻chronic-plus-binge诱导的小鼠肝脏损伤，并减轻小鼠肠道菌群紊乱和肠道粘膜损伤、血清LPS和肿瘤坏死因子α（tumor necrosis factor α, TNFα）增加及肝脏NLRP3炎性小体的活化，提示DADS可通过调控“肝-肠轴”拮抗ALD。（3）DADS可有效的抑制酒精暴露诱导的小鼠肝脏脂肪蓄积和AML12肝细胞脂肪蓄积，而敲除NRF2可以阻断DADS的预防作用，提示DADS抗酒精诱导脂肪肝的作用与NRF2的激活有关。（4）高脂饲料可以促进酒精暴露诱导的小鼠肝损伤、肝脏巨噬细胞M1型极化和肝组织NF-κB和NLRP3炎性小体的激活；游离脂肪酸（free fatty acid, FFA）+酒精联合暴露对AML12肝细胞中NF-κB和NLRP3炎性小体通路无明显作用，而对J774A.1小鼠巨噬细胞NF-κB和NLRP3具有明显的激活；DADS对高脂饲料联合酒精诱导的肝损伤具有明显的拮抗效果。综上，DADS可以通过调控肝脏巨噬细胞极化拮抗ALD，且其作用可能与NRF2活化和肠道稳态维持有关。因而，DADS可能作为饮酒人群的膳食补充剂预防ALD的发病。