Anandamide (arachidonoylethanolamine, AEA), an endogenous agonist for both the cannabinoid CB1 receptor and the vanilloid VR1 receptor, elicits neurobehavioral, anti-inflammatory, immunomodulatory, and proapoptotic effects. Because of the central role of nuclear factor-κB (NF-κB) in the inflammatory process and the immune response, we postulated that AEA might owe some of its effects to the suppression of NF-κB. This study shows that AEA inhibits tumor necrosis factor-α (TNFα)-induced NF-κB activation by direct inhibition of the IκB kinase (IKK)β and, to a lesser extent, the IKKα subunits of κB inhibitor (IκB) kinase complex, and that IKKs inhibition by AEA correlates with inhibition of IκBα degradation, NF-κB binding to DNA, and NF-κB-dependent transcription in TNFα-stimulated cells. AEA also prevents NF-κB-dependent reporter gene expression induced by mitogen-activated protein kinase kinase kinase and NF-κB-inducing kinase. The NF-κB inhibitory activity of AEA was independent of CB1 and CB2activation in TNFα-stimulated 5.1 and A549 cell lines, which do not express vanilloid receptor 1, and was not mediated by hydrolytic products formed through the activity of the enzyme fatty acid amide hydrolase. Chemical modification markedly affected AEA inhibitory activity on NF-κB, suggesting rather narrow structure-activity relationships and the specific interaction with a molecular target. Substitution of the alkyl moiety with less saturated fatty acids generally reduced or abolished activity. However, replacement of the ethanolamine “head” with a vanillyl group led to potent inhibition of TNFα-induced NF-κB-dependent transcription. These findings provide new mechanistic insights into the anti-inflammatory and proapoptotic activities of AEA, and should foster the synthesis of improved analogs amenable to pharmaceutical development as anti-inflammatory agents.
花生四烯醇胺(Anandamide,arachidonoylethanolamine,AEA)是
大麻素 CB1 受体和香草素 VR1 受体的内源性激动剂,具有神经行为、抗炎、免疫调节和促进细胞凋亡的作用。由于核因子-κB(NF-κB)在炎症过程和免疫反应中的核心作用,我们推测 AEA 的部分作用可能是由于抑制了 NF-κB。本研究表明,AEA 通过直接抑制 IκB 激酶(IKK)β,以及在较小程度上抑制κB
抑制剂(IκB)激酶复合物的 IKKα 亚基,从而抑制肿瘤坏死因子-α(TNFα)诱导的 NF-κB 激活、AEA对IKKs的抑制与TNFα刺激细胞中IκBα降解、NF-κB与DNA结合以及NF-κB依赖性转录的抑制相关。AEA 还能阻止由丝裂原活化蛋白激酶激酶和 NF-κB 诱导激酶诱导的 NF-κB 依赖性报告
基因表达。在 TNFα 刺激的 5.1 和 A549
细胞系(不表达
香草醛受体 1)中,AEA 的 NF-κB 抑制活性与 CB1 和 CB2 的激活无关,也不是由
脂肪酸酰胺
水解酶的
水解产物介导的。
化学修饰明显影响了 AEA 对 NF-κB 的抑制活性,表明其结构-活性关系相当狭窄,而且与分子靶点存在特异性相互作用。用饱和度较低的
脂肪酸取代烷基通常会降低或取消活性。然而,用香草基取代
乙醇胺 "头 "可有效抑制 TNFα 诱导的 NF-κB 依赖性转录。这些发现为了解 AEA 的抗炎和促细胞凋亡活性提供了新的机理认识,并有助于合成改良的类似物,作为抗炎药物进行药物开发。