Fu Yue, Jia Jianping
Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, National Clinical Research Center for Geriatric Diseases, Capital Medical University, Beijing, China.
Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, China.
Front Neurosci. 2021 Feb 11;15:638772. doi: 10.3389/fnins.2021.638772. eCollection 2021.
Neuroinflammation and oxidative stress are two major pathological characteristics of Alzheimer's disease (AD). Amyloid-β oligomers (AβO), a toxic form of Aβ, promote the neuroinflammation and oxidative stress in the development of AD. Isoliquiritigenin (ISL), a natural flavonoid isolated from the root of liquorice, has been shown to exert inhibitory effects on inflammatory response and oxidative stress.
The main purpose of this study is to assess the influence of ISL on inflammatory response and oxidative stress in BV2 cells stimulated with AβO, and to explore the underlying molecular mechanisms.
3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H- tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) cytotoxicity assays were used to assess the toxic or protective effects of ISL. The expression levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assays. Morphological changes in BV2 cells were assessed by immunofluorescence method. Nitric oxide (NO) assay kit was used to determinate the NO production. Western blot, qRT-PCR and immunofluorescence were used to explore the underlying molecular mechanisms.
ISL treatment reduced the production of inflammatory cytokines and NO, and alleviated the morphological changes in BV2 cells induced by AβO. ISL treatment further protected N2a cells from the toxic medium of AβO-stimulated BV2 cells. ISL activated nuclear factor erythroid-2 related factor 2 (Nrf2) signaling and suppressed nuclear factor-κB (NF-κB) signaling in BV2 cells.
ISL suppresses AβO-induced inflammation and oxidative stress in BV2 cells the regulation of Nrf2/NF-κB signaling. Therefore, ISL indirectly protects neurons from the damage of toxic conditioned media.
神经炎症和氧化应激是阿尔茨海默病（AD）的两个主要病理特征。淀粉样β寡聚体（AβO）是Aβ的一种毒性形式，在AD的发展过程中促进神经炎症和氧化应激。异甘草素（ISL）是从甘草根中分离出的一种天然黄酮类化合物，已被证明对炎症反应和氧化应激具有抑制作用。
本研究的主要目的是评估ISL对AβO刺激的BV2细胞炎症反应和氧化应激的影响，并探讨其潜在的分子机制。
采用3-(4,5-二甲基-2-噻唑基)-2,5-二苯基-2-H-溴化四氮唑（MTT）和乳酸脱氢酶（LDH）细胞毒性试验评估ISL的毒性或保护作用。通过定量实时聚合酶链反应（qRT-PCR）和酶联免疫吸附试验评估白细胞介素-1β、白细胞介素-6和肿瘤坏死因子-α的表达水平。采用免疫荧光法评估BV2细胞的形态变化。使用一氧化氮（NO）检测试剂盒测定NO的产生。采用蛋白质免疫印迹法、qRT-PCR和免疫荧光法探讨其潜在的分子机制。
ISL处理可减少炎症细胞因子和NO的产生，并减轻AβO诱导的BV2细胞形态变化。ISL处理进一步保护N2a细胞免受AβO刺激的BV2细胞毒性培养基的影响。ISL激活BV2细胞中的核因子红细胞2相关因子2（Nrf2）信号通路并抑制核因子κB（NF-κB）信号通路。
ISL通过调节Nrf2/NF-κB信号通路抑制AβO诱导的BV2细胞炎症和氧化应激。因此，ISL间接保护神经元免受毒性条件培养基的损伤。
