Melatonin modulates TLR4-mediated inflammatory genes through MyD88-and TRIF-dependent signaling pathways in lipopolysaccharide-stimulated RAW264.7 cells
Melatonin modulates TLR4-mediated inflammatory genes through MyD88-and TRIF-dependent signaling pathways in lipopolysaccharide-stimulated RAW264.7 cells
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褪黑激素通过脂多糖刺激的 RAW264.7 细胞中 MyD88 和 TRIF 依赖性信号通路调节 TLR4 介导的炎症基因
DOI：
10.1111/j.1600-079x.2012.01002.x
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发表时间：
2012-11-01
影响因子：
10.3
通讯作者：
Song, Li-Hua
中科院分区：
文献类型：
--
作者：
Xia, Mi-Zhen;Liang, Ying-Li;Song, Li-Hua
越来越多的证据表明褪黑激素具有抗炎作用。然而，分子机制仍然不清楚。在这项研究中，我们研究了褪黑激素对脂多糖（LPS）刺激的巨噬细胞中Toll样受体4（TLR4）介导的分子骨髓分化因子88（MyD88）依赖性和TRIF依赖性信号通路的影响。在不存在或存在褪黑激素（10、100、1000μm）的情况下，将RAW264.7细胞与LPS（2.0μg/mL）一起孵育。正如预期的那样，褪黑激素抑制 LPS 刺激的巨噬细胞中 TLR4 介导的肿瘤坏死因子 α (TNF-α)、白细胞介素 (IL)-1 β、IL-6、IL-8 和 IL-10。此外，褪黑激素显着减弱 LPS 诱导的巨噬细胞中环氧合酶 (COX)-2 和诱导型一氧化氮合酶 (iNOS) 的上调。进一步分析表明，褪黑激素抑制LPS刺激的巨噬细胞中MyD88的表达。虽然褪黑素对 TLR4 介导的 c-Jun N 末端激酶 (JNK)、p38 和细胞外调节蛋白激酶 (ERK) 的磷酸化没有影响，但它显着减弱 LPS 刺激的巨噬细胞中核因子 kappa B (NF-kappa B) 的激活。此外，褪黑激素抑制 LPS 刺激的巨噬细胞中 TLR4 介导的 Akt 磷酸化。此外，褪黑激素显着减弱 LPS 刺激的巨噬细胞中干扰素 (IFN) 调节因子 3 (IRF3) 的升高，该因子参与 TLR4 介导的 TRIF 依赖性信号通路。相应地，褪黑激素显着减轻巨噬细胞中 LPS 诱导的 IFN-β。总之，褪黑激素通过 MyD88 依赖性和 TRIF 依赖性信号通路调节 TLR4 介导的炎症基因。
Increasing evidence demonstrates that melatonin has an anti-inflammatory effect. Nevertheless, the molecular mechanisms remain obscure. In this study, we investigated the effect of melatonin on toll-like receptor 4 (TLR4)-mediated molecule myeloid differentiation factor 88 (MyD88)-dependent and TRIF-dependent signaling pathways in lipopolysaccharide (LPS)-stimulated macrophages. RAW264.7 cells were incubated with LPS (2.0 mu g/mL) in the absence or presence of melatonin (10, 100, 1000 mu m). As expected, melatonin inhibited TLR4-mediated tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-1 beta, IL-6, IL-8, and IL-10 in LPS-stimulated macrophages. In addition, melatonin significantly attenuated LPS-induced upregulation of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) in macrophages. Further analysis showed that melatonin inhibited the expression of MyD88 in LPS-stimulated macrophages. Although it had no effect on TLR4-mediated phosphorylation of c-Jun N-terminal kinase (JNK), p38, and extracellular regulated protein kinase (ERK), melatonin significantly attenuated the activation of nuclear factor kappa B (NF-kappa B) in LPS-stimulated macrophages. In addition, melatonin inhibited TLR4-mediated Akt phosphorylation in LPS-stimulated macrophages. Moreover, melatonin significantly attenuated the elevation of interferon (IFN)-regulated factor-3 (IRF3), which was involved in TLR4-mediated TRIF-dependent signaling pathway, in LPS-stimulated macrophages. Correspondingly, melatonin significantly alleviated LPS-induced IFN-beta in macrophages. In conclusion, melatonin modulates TLR4-mediated inflammatory genes through MyD88-dependent and TRIF-dependent signaling pathways.