基于海马微环境与神经环路共调节探究栀子多组分协同抗抑郁作用机制

The increasing incidence of depression has become a major social problem. Gardeniae Fructus is commonly used in Chinese medicine to treat depression. Previous reports and applicant’s studies have shown that the antidepressant action of Gardeniae Fructus is closely related to the synergetic effects of its multi-components on hippocampal neurogenesis, but the detailed mechanism has not been elucidated yet. And it was found that Gardeniae Fructus showed effects on Hippocampal neurogenic niche and neural circuit with regulation of neurogenesis as well. The following scientific hypothesis was thus proposed - "The antidepressant effect of Gardeniae Fructus is produced by the synergetic effects on neurogenesis of its multi-components through the regulation of Hippocampal neurogenic niche and nerve circuit".Detailed investigations will be performed as follows:(1) To study the specific function of the components of Gardeniae Fructus on neurogenesis, and to confirm that the antidepressant action of Gardeniae Fructus is dependent on neurogenesis; (2) Focusing on the Brain-derived Neurotrophic Factor, the key protein promoting neurogenesis in Hippocampal neurogenic niche, to study the molecular mechanism of active components of Gardeniae Fructus on Neurogenesis; (3) To study the role of neural circuit in the regulation of neural regeneration by Gardeniae Fructus based on chemical genetic technology. (4) Comprehensive analysis of multi-component synergistic antidepressant mechanism of Gardeniae Fructus based on multivariate statistical method, to clarify the scientific connotation of the regulation of neurogenesis by Gardeniae Fructus, and to provide scientific basis for its clinical application and the discovery of antidepressant drugs.

抑郁症发病率日渐增高，已成为威胁人民健康的重大社会问题。中医临床常用栀子治疗抑郁症。前人报道及申请者研究表明，其作用与多类型组分协同促进海马神经再生密切相关，但其协同效应及分子机制尚未阐明；进一步研究发现，栀子对具有调节神经再生的海马微环境与神经环路均有影响。据此提出“栀子多组分调节海马微环境与神经环路，进而协同促进神经再生，产生抗抑郁作用”的科学假说。拟开展工作：（1）研究栀子各组分促进神经再生的具体作用环节，并确认其抗抑郁作用依赖于神经再生；（2）聚焦海马微环境中促进神经再生的关键蛋白——脑源性神经营养因子，探讨栀子有效组分影响神经再生的分子机制；（3）基于化学遗传技术，研究神经环路在栀子有效组分调控神经再生中的作用；（4）基于多变量统计法，整合分析栀子多组分协同抗抑郁作用机制。以期阐明栀子通过调控神经再生多环节进而协同抗抑郁的科学内涵，为其临床应用及抗抑郁药发现提供科学依据。

栀子，一种具有除烦解郁功效的中药，常应用于古今中医临床。其抗抑郁作用的物质基础及分子机制有待进一步阐明。在本项目实施期间共完成了五部分内容，包括栀子资源性化学成分研究；栀子主要活性组分的抗抑郁作用机制研究；栀子环烯醚萜衍生物-栀子蓝的结构研究与活性评价；栀子中活性成分西红花苷防治脑缺血作用机制研究。.栀子抗抑郁作用的物质基础研究方面，我们采用多种色谱技术联用分离栀子资源性化学成分，并基于1D/2D NMR、MS、CD等数据结果进行解析，共发现18种资源性化学成分，包括1个新的单环单萜苷类成分和6种环烯醚萜苷类成分等；以栀子苷、6α-羟基京尼平苷、6β-羟基京尼平苷为底物，合成得到8种栀子蓝类化合物A-H，并筛选出5种高神经活性价值的栀子蓝色素B、D、E、G、H。.栀子活性组分抗抑郁作用机制研究方面，发现给予栀子环烯醚萜组分后，抑郁样小鼠AMPA谷氨酸受体1（GluA1）的表达受到抑制。同时，哺乳动物雷帕霉素靶蛋白（mTOR）、P70核小体S6激酶（P70S6K）和真核生物始动因子4E结合蛋白1（4EBP1）呈现上调趋势。该组分干预后能够逆转应激导致上述蛋白的下降，并上调Synapsin-1、PSD-95等突触相关蛋白和树突棘密度。同时，AMPA受体抑制剂NBQX或mTOR抑制剂雷帕霉素阻断栀子环烯醚萜的药效。以上结果证实了，栀子环烯醚萜通过刺激AMPAR-mTOR信号通路增强突触可塑性而发挥抗抑郁样作用。此外，从栀子有效部位中分离出活性物质西红花苷，我们利用遗传学（GFAP-TK小鼠结合GCV处理）和药理学（TMZ腹腔注射）等方法在多种小鼠抑郁模型中抑制成年神经发生，证实了成年神经发生在西红花苷改善小鼠抑郁样行为中的作用。随后，采用遗传学和药理学方法证实了西红花苷通过激活经典的Wnt/β-catenin信号传导促进海马成年神经发生而表现出抗抑郁作用。这些结果阐明了栀子抗抑郁作用的物质基础及作用的机制，为进一步确立应用栀子改善抑郁症治疗效果奠定了基础。