Eupalinolide B attenuates lipopolysaccharide-induced acute lung injury through inhibition of NF-κB and MAPKs signaling by targeting TAK1 protein

• Published in: International immunopharmacology 2022-10, Vol.111, p.109148-109148, Article 109148
• Main Authors: Yang, Luyao, Chen, Hongqing, Hu, Qiongying, Liu, Lu, Yuan, Yun, Zhang, Chuantao, Tang, Jianyuan, Shen, Xiaofei
• Format: Article
• Language: English
• Subjects: Acute lung injury; Eupalinolide B; Lipopolysaccharide; Macrophages; NF-κB and MAPKs; TAK1
• ISSN: 1567-5769; 1878-1705
• DOI: 10.1016/j.intimp.2022.109148

•Eupalinolide B (EB) inhibit LPS-induced acute lung injury in mice.•EB directly binds to TAK1, and inhibits NF-κB and MAPKs activation.•The α,γ-unsaturated lactone of EB is vital for its anti-inflammatory effect. 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.