黄酮类化合物抑制炎症作用的新型分子机制研究

发布时间：2018-04-09 16:25

本文选题：黄酮类　切入点：Ubc13/Uev2　出处：《浙江大学》2017年博士论文

【摘要】：泛素化,特别是泛素结合酶Ubc13/Uev1介导的K63连接的多聚泛素化在促炎症信号和先天免疫反应中有着关键的调节作用。天然产物黄酮类化合物,如斛皮素、木犀草素等,对一些疾病显示出积极的调节作用,比如抗炎、抗肿瘤和抗氧化等。本项研究主要阐明了黄酮类化合物抗炎作用的新型分子机制。我们首先确定了两种典型黄酮类化合物——斛皮素和木犀草素能够有效地抑制IL-1β和LPS诱导的TAK1-IKK-NF-1κB通路激活和下游靶基因的表达。我们进一步分析并发现了黄酮类化合物显著抑制了胞内K63连接多聚泛素链的合成以及关键蛋白IRAK1和TRAF6的泛素化修饰。通过体外重建的泛素化反应表明黄酮类化合物特异地抑制Ubc13/Uev2介导的K63多聚泛素化,而非其它E2介导的泛素化。进一步的机制研究表明黄酮类化合物直接结合Ubc 13/Uev2,并抑制泛素从Ub～Ubc 13/Uev2中间体释放及随后的泛素链合成。我们测定了 Ubc 13/Uev2和木犀草素或桑色素之间的结合解离平衡常数(KD),分别为24μM和14μM左右,处于较高亲和力的范围。利用现有的黄酮类小分子化合物库进行构效关系分析,表明黄酮类的A、B环上的羟基以及C环的共轭性质是其抑制活力所必需的。我们的研究表明了黄酮类化合物是潜在的Ubc13特异性抑制剂,为理解其所发挥的临床功效提供了一种新的分子机制。同时也说明,黄酮类化合物可以作为前导化合物进一步开发更加高效的Ubc13抑制剂,用于治疗炎症、自身免疫病和肿瘤。
[Abstract]:Ubiquitin, especially the polyubiquitin of K63 ligation mediated by ubiquitin binding enzyme Ubc13/Uev1, plays a key role in promoting inflammatory signal and innate immune response.Natural flavonoids such as Dendrobium luteolin and so on have positive effects on some diseases such as anti-inflammatory anti-tumor and anti-oxidation.This study mainly elucidates the new molecular mechanism of flavonoids anti-inflammatory effect.We first confirmed that two typical flavonoids, Dendrobium and luteolin, could effectively inhibit the activation of TAK1-IKK-NF-1 魏 B pathway induced by IL-1 尾 and LPS and the expression of downstream target genes.We further analyzed and found that flavonoids significantly inhibited the synthesis of intracellular K63 linked polyubiquitin chains and the ubiquitin modification of key proteins IRAK1 and TRAF6.The results showed that flavonoids specifically inhibited Ubc13/Uev2 mediated K63 polyubiquitin, but not other E2 mediated ubiquitization.Further studies showed that flavonoids directly bind to Ubc 13 / Uev2 and inhibit the release of ubiquitin from the intermediate of Ub~Ubc 13/Uev2 and the subsequent synthesis of ubiquitin chain.The binding dissociation equilibrium constants of Ubc 13/Uev2 and luteolin or mulberry were determined, which were about 24 渭 M and 14 渭 M, respectively, and were in a high affinity range.The results of structure-activity analysis by using the existing small flavonoids library show that the hydroxyl groups and the conjugate properties of C-ring are necessary for the inhibition of the activity of flavonoids.Our results suggest that flavonoids are potential Ubc13 specific inhibitors, providing a new molecular mechanism for understanding the clinical efficacy of flavonoids.It is also suggested that flavonoids can be further developed as leading compounds for the development of more efficient Ubc13 inhibitors for the treatment of inflammation, autoimmune diseases and tumors.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R96

【相似文献】