Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China.
Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China.
Redox Biol. 2020 Sep;36:101644. doi: 10.1016/j.redox.2020.101644. Epub 2020 Jul 17.
Microglia-mediated neuroinflammation plays a crucial role in the pathophysiological process of multiple neurological disorders such as ischemic stroke, yet lacks effective therapeutic agents. Previously, we discovered one novel synthetic compound, tanshinol borneol ester (DBZ), possesses anti-inflammatory and anti-atherosclerotic activities, whereas little is known about its effects in CNS. Therefore, the present study aims to explore the effects and potential mechanism of DBZ on neuroinflammation and microglial function. Our studies revealed that DBZ significantly inhibited NF-κB activity, suppressed the production of pro-inflammatory mediators meanwhile promoted M2 mediators expression in LPS-stimulated BV2 cells and mouse primary microglia cells. DBZ also exhibited antioxidant activity by enhancing Nrf2 nuclear accumulation and transcriptional activity, increasing HO-1 and NQO1 expression, and inhibiting LPS-induced ROS generation in BV2 cells. Importantly, the anti-neuroinflammatory and antioxidant effects of DBZ above were reversed by Nrf2 knockdown. Additionally, DBZ ameliorated sickness behaviors of neuroinflammatory mice induced by systemic LPS administration, and significantly reduced infract volume, improved sensorimotor and cognitive function in rats subjected to transient middle cerebral artery occlusion (tMCAO); besides, DBZ restored microglia morphological alterations and shifted the M1/M2 polarization in both murine models. Mechanistically, DBZ-induced Nrf2 nuclear accumulation and antioxidant enzymes expression were accompanied by increased level of p-Akt(Ser473) (activation) and p-GSK3β(Ser9) (inactivation), and decreased nuclear level of Fyn both in vitro and in vivo. Pharmacologically inhibiting PI3K or activating GSK3β markedly increased nuclear density of Fyn in microglia cells, which blocked the promoting effect of DBZ on Nrf2 nuclear accumulation and its antioxidant and anti-neuroinflammatory activities. Collectively, these results indicated the effects of DBZ on microglia-mediated neuroinflammation were strongly associated with the nuclear accumulation and stabilization of Nrf2 via the Akt(Ser473)/GSK3β(Ser9)/Fyn pathway. With anti-neuroinflammatory and antioxidant properties, DBZ could be a promising new drug candidate for prevention and/or treatment of cerebral ischemia and other neuroinflammatory disorders.
小胶质细胞介导的神经炎症在多种神经疾病的病理生理过程中发挥着关键作用，如缺血性中风，但目前缺乏有效的治疗药物。先前，我们发现一种新型合成化合物丹参醇冰片酯（DBZ）具有抗炎和抗动脉粥样硬化作用，而其在中枢神经系统（CNS）中的作用知之甚少。因此，本研究旨在探讨 DBZ 对神经炎症和小胶质细胞功能的影响及其潜在机制。我们的研究表明，DBZ 可显著抑制 NF-κB 活性，抑制 LPS 刺激的 BV2 细胞和小鼠原代小胶质细胞中促炎介质的产生，同时促进 M2 介质的表达。DBZ 还通过增强 Nrf2 核积累和转录活性、增加 HO-1 和 NQO1 的表达以及抑制 LPS 诱导的 BV2 细胞中 ROS 的产生来发挥抗氧化作用。重要的是，Nrf2 敲低逆转了 DBZ 的上述抗炎和抗氧化作用。此外，DBZ 改善了系统 LPS 给药诱导的神经炎症小鼠的病态行为，并显著减少了短暂性大脑中动脉闭塞（tMCAO）大鼠的梗死体积，改善了感觉运动和认知功能；此外，DBZ 恢复了两种小鼠模型中小胶质细胞的形态改变，并改变了 M1/M2 极化。在机制上，DBZ 诱导的 Nrf2 核积累和抗氧化酶表达伴随着体外和体内 p-Akt(Ser473)（激活）和 p-GSK3β(Ser9)（失活）水平的增加以及 Fyn 核水平的降低。PI3K 药理学抑制或 GSK3β 激活显著增加了小胶质细胞中 Fyn 的核密度，从而阻断了 DBZ 对 Nrf2 核积累及其抗氧化和抗炎作用的促进作用。总之，这些结果表明，DBZ 对小胶质细胞介导的神经炎症的作用与 Nrf2 的核积累和稳定密切相关，通过 Akt(Ser473)/GSK3β(Ser9)/Fyn 途径。DBZ 具有抗炎和抗氧化特性，可能成为预防和/或治疗脑缺血和其他神经炎症性疾病的有前途的新药候选物。
