Chen Lin, Li Ruimei, Chen Feiyan, Zhang Hantao, Zhu Zhu, Xu Shuyi, Cheng Yao, Zhao Yunan
Department of Physiology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China.
Research and Innovation Center, College of Traditional Chinese Medicine Integrated Chinese and Western Medicine College, Nanjing University of Chinese Medicine, Nanjing, China.
J Ginseng Res. 2022 Sep;46(5):666-674. doi: 10.1016/j.jgr.2021.12.004. Epub 2021 Dec 17.
Ginsenosides and their metabolites have antidepressant-like effects, but the underlying mechanisms remain unclear. We previously identified 14-3-3 ζ as one of the target proteins of 20 (S)-protopanaxadiol (PPD), a fully deglycosylated ginsenoside metabolite.
Corticosterone (CORT) was administered repeatedly to induce the depression model, and PPD was given concurrently. The tail suspension test (TST) and the forced swimming test (FST) were used for behavioral evaluation. All mice were sacrificed. Golgi-cox staining, GSK 3β activity assay, and Western blot analysis were performed. In vitro, the kinetic binding analysis with the Biolayer Interferometry (BLI) was used to determine the molecular interactions.
TST and FST both revealed that PPD reversed CORT-induced behavioral deficits. PPD also ameliorated the CORT-induced expression alterations of hippocampal Ser9 phosphorylated glycogen synthase kinase 3β (p-Ser9 GSK 3β), Ser133 phosphorylated cAMP response element-binding protein (p-Ser133 CREB), and brain-derived neurotrophic factor (BDNF). Moreover, PPD attenuated the CORT-induced increase in GSK 3β activity and decrease in dendritic spine density in the hippocampus. In vitro, 14-3-3 ζ protein specifically bound to p-Ser9 GSK 3β polypeptide. PPD promoted the binding and subsequently decreased GSK 3β activity.
These findings demonstrated the antidepressant-like effects of PPD on the CORT-induced mouse depression model and indicated a possible target-based mechanism. The combination of PPD with the 14-3-3 ζ protein may promote the binding of 14-3-3 ζ to p-GSK 3β (Ser9) and enhance the inhibition of Ser9 phosphorylation on GSK 3β kinase activity, thereby activating the plasticity-related CREB-BDNF signaling pathway.
人参皂苷及其代谢产物具有抗抑郁样作用，但其潜在机制尚不清楚。我们之前鉴定出14-3-3ζ是一种完全去糖基化的人参皂苷代谢产物20（S）-原人参二醇（PPD）的靶蛋白之一。
反复给予皮质酮（CORT）以诱导抑郁模型，并同时给予PPD。采用悬尾试验（TST）和强迫游泳试验（FST）进行行为学评估。处死所有小鼠。进行高尔基-考克斯染色、GSK 3β活性测定和蛋白质印迹分析。在体外，采用生物层干涉术（BLI）进行动力学结合分析以确定分子相互作用。
TST和FST均显示PPD可逆转CORT诱导的行为缺陷。PPD还改善了CORT诱导的海马中Ser9磷酸化糖原合酶激酶3β（p-Ser9 GSK 3β）、Ser133磷酸化环磷酸腺苷反应元件结合蛋白（p-Ser133 CREB）和脑源性神经营养因子（BDNF）的表达改变。此外，PPD减弱了CORT诱导的海马中GSK 3β活性增加和树突棘密度降低。在体外，14-3-3ζ蛋白特异性结合p-Ser9 GSK 3β多肽。PPD促进了这种结合，随后降低了GSK 3β活性。
这些发现证明了PPD对CORT诱导的小鼠抑郁模型具有抗抑郁样作用，并表明了一种可能基于靶点的机制。PPD与14-3-3ζ蛋白的结合可能促进14-3-3ζ与p-GSK 3β（Ser9）的结合，并增强对GSK 3β激酶活性的Ser9磷酸化抑制作用，从而激活与可塑性相关的CREB-BDNF信号通路。
