College of Pharmaceutical Science, Zhejiang University, 866 Yu Hangtang Road, Hangzhou, China.
Laboratory for Intestinal Ecosystem, RIKEN Center for Intestinal Ecosystem, Yokohama 230- 0045, Japan.
Phytomedicine. 2023 May;113:154730. doi: 10.1016/j.phymed.2023.154730. Epub 2023 Feb 24.
In our previous study, we found that gentiopicroside (GPS) isolated from Gentiana rigescens Franch has a significant antiaging activity via regulation of mitophagy and oxidative stress. In order to increase the anti-aging activity of GPS, several compounds based on the chemical structure of GPS were synthesized and evaluated for bioactivity with yeast replicative lifespan assay, and 2H-gentiopicroside (2H-GPS) as leading compound was selected for AD treatment.
To investigate whether 2H-GPS has anti- Alzheimer's disease effects, we used D-galactose (Dgal)-induced model mice to evaluate the effect of 2H-GPS on AD mice. Furthermore, we explored the action mechanism of this compound with RT-PCR, Western Blot, ELISA and 16S rRNA gene sequence analysis.
Memory dysfunction and reduction in the number of neurons in the brain of mice were observed in Dgal treated group. These symptoms of AD mice were significantly relieved by administering 2H-GPS and donepezil (Done), respectively. In the Dgal only treated group, the protein levels of β-catenin, REST and phosphorylated GSK-3β, involved in the Wnt signaling pathway were significantly decreased, whereas the protein levels of GSK-3β, Tau, phosphorylated Tau, P35 and PEN-2 were significantly increased. Importantly, treatment with 2H-GPS resulted in restoration of memory dysfunction and levels of these proteins. Furthermore, the composition of the gut microbiota after 2H-GPS administration was explored through 16S rRNA gene sequence analysis. Moreover, the mice, in which depleted gut microbiota with antibiotic cocktail (ABX), were used for evaluation of whether the gut microbiota is involved to the effect of 2H-GPS. Significant changes in gut microbiota composition were observed between AD and 2H-GPS-treated AD mice, and ABX partially eliminated the AD-restoring effect of 2H-GPS.
2H-GPS improves the symptoms of AD mice through combination of the regulation of Wnt signaling pathway and the microbiota-gut-brain axis, and the mechanism of action of 2H-GPS is distinct from that of Done.
在我们之前的研究中，我们发现从秦艽中分离得到的龙胆苦苷（GPS）通过调节线粒体自噬和氧化应激具有显著的抗衰老活性。为了提高 GPS 的抗衰老活性，我们根据 GPS 的化学结构合成了几种化合物，并通过酵母复制寿命测定法对其生物活性进行了评估，其中 2H-龙胆苦苷（2H-GPS）被选为治疗 AD 的先导化合物。
为了研究 2H-GPS 是否具有抗阿尔茨海默病的作用，我们使用 D-半乳糖（D-gal）诱导的模型小鼠来评估 2H-GPS 对 AD 小鼠的作用。此外，我们通过 RT-PCR、Western Blot、ELISA 和 16S rRNA 基因序列分析探讨了该化合物的作用机制。
D-gal 处理组小鼠表现出记忆功能障碍和大脑神经元数量减少。用 2H-GPS 和多奈哌齐（Done）分别处理 AD 小鼠可显著缓解这些 AD 症状。在仅用 D-gal 处理的组中，Wnt 信号通路相关的β-连环蛋白、REST 和磷酸化 GSK-3β 的蛋白水平显著降低，而 GSK-3β、Tau、磷酸化 Tau、P35 和 PEN-2 的蛋白水平显著升高。重要的是，用 2H-GPS 处理可恢复记忆功能障碍和这些蛋白的水平。此外，通过 16S rRNA 基因序列分析探讨了用 2H-GPS 给药后肠道微生物组的组成。此外，用抗生素鸡尾酒（ABX）耗尽肠道微生物组的小鼠用于评估肠道微生物组是否参与 2H-GPS 的作用。AD 小鼠和 2H-GPS 处理的 AD 小鼠之间的肠道微生物组组成发生了显著变化，ABX 部分消除了 2H-GPS 对 AD 的恢复作用。
2H-GPS 通过调节 Wnt 信号通路和微生物群-肠道-大脑轴来改善 AD 小鼠的症状，其作用机制与 Done 不同。
