Zeng Ke-Wu, Yu Qian, Liao Li-Xi, Song Fang-Jiao, Lv Hai-Ning, Jiang Yong, Tu Peng-Fei
State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China.
Research Studio of Integration of Traditional and Western Medicine, First Hospital, Peking University, Beijing, 100034, China.
J Cell Biochem. 2015 Jul;116(7):1286-99. doi: 10.1002/jcb.25084.
MC13 is a novel coumarin compound found in Murraya, an economic crop whose leaves are widely used as condiment (curry) in cuisine. The aims of the present study were to investigate the neuroprotective effects of MC13 on microglia-mediated inflammatory injury model as well as potential molecular mechanism. Cell viability and apoptosis assay demonstrated that MC13 was not toxic to neurons and significantly protected neurons from microglia-mediated inflammatory injury upon lipopolysaccharide (LPS) stimulation. Results showed that MC13 markedly inhibited LPS-induced production of various inflammatory mediators, including nitrite oxide (Griess method), TNF-α and IL-6 (ELISA assay) in a concentration-dependent manner. Mechanism study showed that MC13 could suppress the activation of NF-κB, which was the central regulator for inflammatory response, and also decreased the interaction of TGF-β-activated kinase 1 (TAK1)-binding protein (TAB2) with TAK1 and TNF receptor associated factor (TRAF6), leading to the decreased phosphorylation levels of NF-κB upstream regulators such as IκB and IκB kinase (IKK). MC13 also significantly down-regulated the phosphorylation levels of ERK and p38 MAPKs, which played key roles in microglia-mediated inflammatory response. Furthermore, MC13 inhibited Jak2-dependent Stat1/3 signaling pathway activation by blocking Jak2 phosphorylation, Stat1/3 phosphorylation, and nuclear translocation. Taken together, our results demonstrated that MC13 protected neurons from microglia-mediated neuroinflammatory injury by inhibiting TRAF6-TAK1-NF-κB, p38/ERK MAPKs, and Jak2-Stat1/3 pathways. Finally, MC13 might interact with LPS and interfere LPS-binding to cell membrane surface. These findings suggested that coumarin might act as a potential medicinal agent for treating neuroinflammation as well as inflammation-related neurodegenerative diseases.
MC13是一种在九里香中发现的新型香豆素化合物，九里香是一种经济作物，其叶子在烹饪中被广泛用作调味品（咖喱）。本研究的目的是研究MC13对小胶质细胞介导的炎症损伤模型的神经保护作用及其潜在的分子机制。细胞活力和凋亡检测表明，MC13对神经元无毒，并且在脂多糖（LPS）刺激下能显著保护神经元免受小胶质细胞介导的炎症损伤。结果显示，MC13以浓度依赖的方式显著抑制LPS诱导的各种炎症介质的产生，包括一氧化氮（Griess法）、肿瘤坏死因子-α和白细胞介素-6（ELISA检测）。机制研究表明，MC13可以抑制炎症反应的中心调节因子NF-κB的激活，还能减少转化生长因子-β激活激酶1（TAK1）结合蛋白（TAB2）与TAK1以及肿瘤坏死因子受体相关因子（TRAF6）的相互作用，导致NF-κB上游调节因子如IκB和IκB激酶（IKK）的磷酸化水平降低。MC13还显著下调了在小胶质细胞介导的炎症反应中起关键作用的ERK和p38丝裂原活化蛋白激酶（MAPK）的磷酸化水平。此外，MC13通过阻断Jak2磷酸化、Stat1/3磷酸化和核转位来抑制Jak2依赖性Stat1/3信号通路的激活。综上所述，我们的结果表明，MC13通过抑制TRAF6-TAK1-NF-κB、p38/ERK MAPK和Jak2-Stat1/3信号通路，保护神经元免受小胶质细胞介导的神经炎症损伤。最后，MC13可能与LPS相互作用并干扰LPS与细胞膜表面的结合。这些发现表明，香豆素可能作为一种潜在的药物用于治疗神经炎症以及与炎症相关的神经退行性疾病。
