Curcumin Analog L48H37 Prevents Lipopolysaccharide-Induced TLR4 Signaling Pathway Activation and Sepsis via Targeting MD2
作者:Yi Wang、Xiaoou Shan、Yuanrong Dai、Lili Jiang、Gaozhi Chen、Yali Zhang、Zhe Wang、Lili Dong、Jianzhang Wu、Guilong Guo、Guang Liang
DOI:10.1124/jpet.115.222570
日期:2015.6
Endotoxin-induced acute inflammatory diseases such as sepsis, mediated by excessive production of various proinflammatory cytokines, remain the leading cause of mortality in critically ill patients. Lipopolysaccharide (LPS), the characteristic endotoxin found in the outer membrane of Gram-negative bacteria, can induce the innate immunity system and through the myeloid differentiation protein 2 (MD2) and Toll-like receptor 4 (TLR4) complex, increase the production of inflammatory mediators. Our previous studies have found that a curcumin analog, L48H37 [1-ethyl-3,5-bis(3,4,5-trimethoxybenzylidene)piperidin-4-one], was able to inhibit LPS-induced inflammation, particularly tumor necrosis factor α and interleukin 6 production and gene expression in mouse macrophages. In this study, a series of biochemical experiments demonstrate L48H37 specifically targets MD2 and inhibits the interaction and signaling transduction of LPS-TLR4/MD2. L48H37 binds to the hydrophobic region of MD2 pocket and forms hydrogen bond interactions with Arg90 and Tyr102. Subsequently, L48H37 was shown to suppress LPS-induced mitogen-activated protein kinase phosphorylation and nuclear factor κ B activation in macrophages; it also dose dependently inhibits the cytokine expression in macrophages and human peripheral blood mononuclear cells stimulated by LPS. In LPS-induced septic mice, both pretreatment and treatment with L48H37 significantly improved survival and protected lung injury. Taken together, this work identified a new MD2 specific inhibitor, L48H37, as a potential candidate in the treatment of sepsis.
内毒素诱发的急性炎症性疾病(如败血症)由各种促炎细胞因子的过度分泌所介导,仍然是危重病人死亡的主要原因。脂多糖(LPS)是革兰氏阴性细菌外膜中特有的内毒素,可诱导先天性免疫系统,并通过髓系分化蛋白 2(MD2)和 Toll 样受体 4(TLR4)复合物增加炎症介质的产生。我们之前的研究发现,姜黄素类似物 L48H37 [1-ethyl-3,5-bis(3,4,5-trimethoxybenzylidene)piperidin-4-one] 能够抑制 LPS 诱导的炎症,尤其是小鼠巨噬细胞中肿瘤坏死因子 α 和白细胞介素 6 的产生和基因表达。在本研究中,一系列生化实验证明 L48H37 能特异性地靶向 MD2,抑制 LPS-TLR4/MD2 的相互作用和信号转导。L48H37 与 MD2 口袋的疏水区域结合,并与 Arg90 和 Tyr102 形成氢键相互作用。随后的研究表明,L48H37 可抑制 LPS 诱导的巨噬细胞中丝裂原活化蛋白激酶磷酸化和核因子 κ B 的活化;它还能依赖剂量抑制受 LPS 刺激的巨噬细胞和人类外周血单核细胞中细胞因子的表达。在 LPS 诱导的败血症小鼠中,L48H37 的预处理和治疗都能显著提高存活率,保护肺损伤。综上所述,这项研究发现了一种新的 MD2 特异性抑制剂 L48H37,它是治疗败血症的潜在候选药物。