Abstract：
Acute lung injury (ALI) is a life-threatening disease characterized by severe inflammatory response, which has no pharmacological therapy in clinic. In this study, we found that eupalinolide B (EB), a sesquiterpene lactone isolated from Eupatorium lindleyanum, significantly ameliorated lipopolysaccharide (LPS)-induced ALI in mice, which manifests as reduction in lung injury score, activity of myeloperoxidase, and release of cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), and monocyte chemoattractant protein-1 (MCP-1). In RAW264.7 murine macrophages, EB effectively inhibited LPS-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2) by down-regulating the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2), respectively. Mechanistically, EB not only blocked LPS-induced phosphorylation of inhibitor of nuclear factor kappa B kinase-α/β (IKKα/β), phosphorylation and degradation of inhibitor of nuclear factor-kappa B alpha (IκBα), and phosphorylation and nuclear translocation of nuclear factor-kappa B (NF-κB) P65, but also suppressed LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs) in vitro or in vivo. Through cellular thermal shift assay and western blotting, EB was demonstrated to target and inactivate transforming growth factor β activated kinase-1 (TAK1), which is an important upstream kinase for the activation of NF-κB and MAPKs pathways. Additionally, EB-mediated actions were markedly abolished by dithiothreitol in LPS-exposed RAW264.7 cells, suggesting a crucial role of the α,γ-unsaturated lactone for the anti-inflammatory activity of EB. In conclusion, our findings showed that EB could effectively alleviate ALI in mice, and attenuate inflammatory response by inhibiting the activation of TAK1, and TAK1-mediated activation of NF-κB and MAPKs cascades.
摘要：
急性肺损伤(ALI)是一种以严重炎症反应为特征的危及生命的疾病,在临床上没有药物治疗。在这项研究中,我们发现乙丙内酯B(EB)，从紫茎泽兰分离的倍半萜内酯，显著改善脂多糖（LPS）诱导的小鼠ALI，表现为肺损伤评分降低，髓过氧化物酶的活性，和释放细胞因子白细胞介素（IL）-1β，IL-6,肿瘤坏死因子-α(TNF-α),和单核细胞趋化蛋白-1(MCP-1)。在RAW264.7鼠巨噬细胞中，EB通过下调诱导型一氧化氮合酶（iNOS）和环氧合酶-2（COX2）的表达，有效抑制LPS诱导的一氧化氮（NO）和前列腺素E2（PGE2）的产生，分别。机械上,EB不仅阻断LPS诱导的核因子κB激酶-α/β（IKKα/β）抑制剂的磷酸化，核因子-κBα（IκBα）抑制剂的磷酸化和降解，以及核因子-κB（NF-κB）P65的磷酸化和核易位，但也在体外或体内抑制了LPS诱导的丝裂原活化蛋白激酶（MAPK）的磷酸化。通过细胞热转移分析和蛋白质印迹，EB被证明靶向和灭活转化生长因子β激活的激酶-1（TAK1），它是NF-κB和MAPK通路激活的重要上游激酶。此外,在LPS暴露的RAW264.7细胞中，二硫苏糖醇明显消除了EB介导的作用，表明α的关键作用，用于EB的抗炎活性的γ-不饱和内酯。总之,我们的发现表明EB可以有效缓解小鼠的ALI，并通过抑制TAK1的激活和TAK1介导的NF-κB和MAPKs级联的激活来减轻炎症反应。
