结构多样性合成结合XBP1激活导向的黄连碱结构修饰及构效关系研究

Recent investigations have reported that patients suffering from Ulcerative colitis (UC) have always shown variations in the coding region of X-box-binding protein 1 (XBP1), leading to individuals more sensitive to causative factors of UC. UC can be induced and deteriorated when the expression of XBP1 gene deleted or being down. As a result, XBP1 was proposed to be a new and potential drug target for the treatment of UC. As a new pharmaceutical activity index of anti-UC, activation effect of XBP1 attracted our attention. Our team has established characteristic XBP1 high-throughput drug screening target model in vitro and discovered, in drug screening of anti-UC, that a series of coptisine analogues obtained by structure modification on quaternary coptisine ammonium salt showed significant activation effect on XBP1. Preliminary studies on structure-avtivity relationships and animal tests showed that dihydrocoptisine skeliton is possibly one of the key structure characteristics for activating XBP1. Thus, it is very important to investigate the chemical reactivities of coptisine and clarify the key structure characteristics involving anti-UC activity of coptisine analogues. This project is going to investigate systimatically the structural modification of quaternary coptisine ammonium salt to obtain structure diversities, carry out screening of activation effect on XBP1 in vitro, and conduct animal tests. The discovery of characteristic XBP1 activators and the clarification of structure-activity relationships are the major ends of this project, which will lay the foundation of developping original new drugs of anti-UC with quaternary coptisine ammonium salt as lead compound.

近期研究发现，溃疡性结肠炎(UC)患者在XBP1基因编码区有变异，导致个体对UC诱发因素极其敏感；XBP1表达的缺失或下调会促进UC发生并加重病情发展。因此推测,XBP1可能成为治疗UC的新药物作用靶点。XBP1激活作为新的抗UC活性指标引起了我们的关注。本项目建立了特异的体外靶向XBP1高通量药物筛选模型；在定向进行抗UC药物筛选中发现：以黄连碱为先导物合成的一类黄连碱类似物有显著的XBP1激活效应。初步构效关系和动物实验研究表明，二氢黄连碱母核可能对XBP1激活发挥重要作用，是关键结构之一。所以，以黄连碱为先导物，深入研究其化学反应性能，获得具有结构多样性的黄连碱类似物，阐明与抗UC活性相关的关键结构特征是必要的。本项目对黄连碱进行系统的结构改造，扩展化学结构多样性；进行体外XBP1激活效应筛选和动物试验，达到发现特异性XBP1激活剂、阐明构效关系、奠定抗UC创新药物研究基础的目标。

X-盒结合蛋白-1（XBP1)是一个与肠道上皮细胞内的非可控性内质网应激反应相关的下游关键转录因子。研究发现，正常XBP1功能的缺失或下调会促进溃疡性结肠炎（UC）的发生、发展和恶化；XBP1可能成为治疗UC的新药物作用靶点。但除本项目之外，目前尚未有其他文献展开基于XBP1靶点的抗UC药物的基础和应用研究。.黄连碱具有多种生理活性。在发现以黄连碱为先导物合成的一系列类似物具有XBP1激活活性的基础上开展了本项目的研究。以氯化黄连碱季铵盐为起始原料，以结构多样性和XBP1激活为导向，结合黄连碱的结构与性质并兼顾综合成药性，对黄连碱开展了一些列的结构修饰研究。设计并合成了20多个类型共180多个黄连碱衍生物，包括了大量结构新颖的化合物，对一些与新颖结构的合成相关的反应做出了合理的机理推测。在对正常肠上皮细胞开展细胞毒性检测的基础上，对所合成的目标化合物进行了包括浓度依赖性实验的体外XBP1激活活性评价；对活性化合物的体内药理活性进行了系统的实验和评价，获得了具有抗UC潜力和新作用靶点的目标分子；活性化合物包括一些新结构。本项目所取得的主要研究结果如下：(1) 活性黄连碱类似物对正常细胞安全，适合于进一步研究抗溃疡性结肠炎活性；（2）活性化合物在体外实验中能显著激活XBP1的转录；（3）活性化合物有很好的浓度依赖关系，系列化合物的EC50值在10-8~10-9 M水平；（4）基于体重变化、疾病活动指数、结肠大体损伤指数、结肠挛缩率以及病理检测等指标的抗UC动物体内药效实验结果显示所获得的活性化合物的活性明显优于阳性对照药。项目对活性化合物系列进行了构效关系的探讨和总结。本项目研究结果为黄连碱类似物的创新药物研究提供了科学依据。