Stroke Center and Stroke Section, Department of Neurology, College of Medicine, Chang Gung Memorial Hospital, Linkou Medical Center and Chang Gung University, Taoyuan, Taiwan.
Division of Chinese Internal Medicine, Center for Traditional Chinese Medicine, Chang Gung Memorial Hospital and School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
J Neuroinflammation. 2020 Jun 6;17(1):177. doi: 10.1186/s12974-020-01859-5.
Upregulation of matrix metalloproteinase-9 (MMP-9) has been indicated as one of the inflammatory biomarkers. In the central nervous system (CNS), the MMP-9 is induced by several proinflammatory mediators and participates in the CNS disorders, including inflammation and neurodegeneration. In addition, protein kinase Cs (PKCs) has been shown to be involved in regulation of various inflammatory factors like MMP-9 by several stimuli in many cell types. Several phytochemicals are believed to reduce the risk of several inflammatory disorders including the CNS diseases. The rottlerin, a principal phenolic compound of the Kamala plant Mallotus philippinensis, has been shown to possess an array of medicinal properties, including anti-PKC-δ, antitumor, anti-oxidative, and anti-inflammatory activities.
Herein, we used rat brain astrocytes (RBA) to demonstrate the signaling mechanisms of phorbol 12-myristate 13-acetate (PMA)-induced MMP-9 expression by zymographic, RT-PCR, subcellular isolation, Western blot, ROS detection, and promoter reporter analyses. Then, we evaluate the effects of rottlerin on PMA-induced MMP-9 expression in RBA and its influencing mechanism.
We first demonstrated that PMA stimulated activation of various types of PKC, including PKC-δ in RBA. Subsequently, PMA induced MMP-9 expression via PKCδ-mediated reactive oxygen species (ROS) generation, extracellular signal-regulated kinase 1/2 (ERK1/2) activation, and then induced c-Fos/AP-1 signaling pathway. Finally, upregulation of MMP-9 by PMA via the pathway may promote astrocytic migration, and the event could be attenuated by rottlerin.
These data indicated that rottlerin may have anti-inflammatory activity by reducing these related pathways of PKC-δ-dependent ROS-mediated MMP-9 expression in brain astrocytes.
基质金属蛋白酶-9（MMP-9）的上调已被认为是炎症生物标志物之一。在中枢神经系统（CNS）中，几种促炎介质诱导 MMP-9，并参与包括炎症和神经退行性变在内的 CNS 疾病。此外，蛋白激酶 C（PKC）已被证明参与多种细胞类型中几种炎症因子（如 MMP-9）的调节。几种植物化学物质被认为可以降低包括 CNS 疾病在内的几种炎症性疾病的风险。罗特林是 Kamala 植物 Mallotus philippinensis 的主要酚类化合物，已被证明具有多种药用特性，包括抗 PKC-δ、抗肿瘤、抗氧化和抗炎活性。
本文采用大鼠脑星形胶质细胞（RBA），通过明胶酶谱、RT-PCR、亚细胞分离、Western blot、ROS 检测和启动子报告分析，证明了佛波醇 12-肉豆蔻酸 13-乙酸酯（PMA）诱导 MMP-9 表达的信号机制。然后，我们评估了罗特林对 RBA 中 PMA 诱导的 MMP-9 表达的影响及其影响机制。
我们首先证明 PMA 刺激 RBA 中各种类型的 PKC，包括 PKC-δ的激活。随后，PMA 通过 PKCδ介导的活性氧（ROS）生成、细胞外信号调节激酶 1/2（ERK1/2）激活诱导 MMP-9 表达，然后诱导 c-Fos/AP-1 信号通路。最后，PMA 通过该途径上调 MMP-9 可能促进星形胶质细胞迁移，该事件可被罗特林减弱。
这些数据表明，罗特林可能通过减少 PKC-依赖性 ROS 介导的 MMP-9 表达相关通路在脑星形胶质细胞中的活性，具有抗炎活性。
