Abstract：
BACKGROUND: Xiaoyaosan (XYS), a traditional Chinese medicine formulation, has been used in the treatment of depression. However, no studies have yet identified the active compounds responsible for its antidepressant effects in the brain.
METHODS: We investigated the antidepressants effects of XYS and identified 18β-glycyrrhetinic acid (18β-GA) as the primary compound present in the brain following XYS injection. Furthermore, we explored the molecular mechanisms underlying the antidepressant-like effects of both XYS and 18β-GA.
METHODS: To investigate the antidepressant-like effects of XYS and elucidate the associated molecular mechanisms, we employed various methodologies, including cell cultures, the chronic social defeat stress (CSDS) model, behavioral tests, immunoprecipitation, quantitative PCR (qPCR) assays, Western blotting assays, luciferase assays, chromatin immunoprecipitation (ChIP) assays, immunofluorescence staining, and dendritic spine analysis.
RESULTS: We identified 18β-GA as the primary compound in the brain following XYS injection. In vitro, 18β-GA was found to bind with ERK (extracellular signal-regulated kinase), subsequently activating ERK kinase activity toward both c-Jun and cAMP response element binding protein (CREB). Moreover, 18β-GA activated brain-derived neurotrophic factor (BDNF) transcription by stimulating nuclear factor-erythroid factor 2-related factor 2 (Nrf2), c-Jun, and CREB, while also inhibiting methyl CpG binding protein 2 (MeCP2) both in vitro and in vivo. Chronic intraperitoneal (i.p.) administration of 18β-GA exhibited prophylactic antidepressant-like effects in a CSDS model, primarily by activating BDNF transcription in the medial prefrontal cortex (mPFC). Interestingly, a single i.p. injection of 18β-GA produced rapid and sustained antidepressant-like effects in CSDS-susceptible mice by engaging the BDNF-tropomyosin receptor kinase B (TrkB) signaling pathway in the mPFC.
CONCLUSIONS: These findings suggest that the activation of BDNF transcription in the mPFC underlies the antidepressant-like effects of 18β-GA, a key component of XYS in the brain.
METHODS: We investigated the antidepressants effects of XYS and identified 18β-glycyrrhetinic acid (18β-GA) as the primary compound present in the brain following XYS injection. Furthermore, we explored the molecular mechanisms underlying the antidepressant-like effects of both XYS and 18β-GA.
METHODS: To investigate the antidepressant-like effects of XYS and elucidate the associated molecular mechanisms, we employed various methodologies, including cell cultures, the chronic social defeat stress (CSDS) model, behavioral tests, immunoprecipitation, quantitative PCR (qPCR) assays, Western blotting assays, luciferase assays, chromatin immunoprecipitation (ChIP) assays, immunofluorescence staining, and dendritic spine analysis.
RESULTS: We identified 18β-GA as the primary compound in the brain following XYS injection. In vitro, 18β-GA was found to bind with ERK (extracellular signal-regulated kinase), subsequently activating ERK kinase activity toward both c-Jun and cAMP response element binding protein (CREB). Moreover, 18β-GA activated brain-derived neurotrophic factor (BDNF) transcription by stimulating nuclear factor-erythroid factor 2-related factor 2 (Nrf2), c-Jun, and CREB, while also inhibiting methyl CpG binding protein 2 (MeCP2) both in vitro and in vivo. Chronic intraperitoneal (i.p.) administration of 18β-GA exhibited prophylactic antidepressant-like effects in a CSDS model, primarily by activating BDNF transcription in the medial prefrontal cortex (mPFC). Interestingly, a single i.p. injection of 18β-GA produced rapid and sustained antidepressant-like effects in CSDS-susceptible mice by engaging the BDNF-tropomyosin receptor kinase B (TrkB) signaling pathway in the mPFC.
CONCLUSIONS: These findings suggest that the activation of BDNF transcription in the mPFC underlies the antidepressant-like effects of 18β-GA, a key component of XYS in the brain.
摘要：
背景：逍遥散（XYS），中药配方，已用于治疗抑郁症。然而,目前还没有研究确定其在大脑中具有抗抑郁作用的活性化合物。
方法：我们研究了XYS的抗抑郁作用，并确定了18β-甘草次酸（18β-GA）是XYS注射后脑中存在的主要化合物。此外，我们探讨了XYS和18β-GA抗抑郁样作用的分子机制.
方法：为了研究XYS的抗抑郁样作用并阐明相关的分子机制，我们采用了各种方法，包括细胞培养,慢性社会失败压力(CSDS)模型，行为测试,免疫沉淀,定量PCR（qPCR）测定，蛋白质印迹试验,荧光素酶测定,染色质免疫沉淀（ChIP）测定，免疫荧光染色，和树突脊柱分析。
结果:我们鉴定了XYS注射后脑中的主要化合物18β-GA。体外，发现18β-GA与ERK（细胞外信号调节激酶）结合，随后激活ERK激酶对c-Jun和cAMP反应元件结合蛋白（CREB）的活性。此外，18β-GA通过刺激核因子-红细胞相关因子2（Nrf2）激活脑源性神经营养因子（BDNF）转录，c-Jun,CREB,同时还在体外和体内抑制甲基CpG结合蛋白2（MeCP2）。在CSDS模型中，18β-GA的慢性腹膜内（i.p.）给药表现出预防性抗抑郁样作用，主要通过激活内侧前额叶皮层（mPFC）中的BDNF转录。有趣的是,通过在mPFC中参与BDNF-原肌球蛋白受体激酶B（TrkB）信号通路，单次腹膜内注射18β-GA在CSDS易感小鼠中产生了快速和持续的抗抑郁样作用。
结论：这些发现表明，mPFC中BDNF转录的激活是18β-GA抗抑郁样作用的基础，大脑中XYS的关键组成部分。
方法：我们研究了XYS的抗抑郁作用，并确定了18β-甘草次酸（18β-GA）是XYS注射后脑中存在的主要化合物。此外，我们探讨了XYS和18β-GA抗抑郁样作用的分子机制.
方法：为了研究XYS的抗抑郁样作用并阐明相关的分子机制，我们采用了各种方法，包括细胞培养,慢性社会失败压力(CSDS)模型，行为测试,免疫沉淀,定量PCR（qPCR）测定，蛋白质印迹试验,荧光素酶测定,染色质免疫沉淀（ChIP）测定，免疫荧光染色，和树突脊柱分析。
结果:我们鉴定了XYS注射后脑中的主要化合物18β-GA。体外，发现18β-GA与ERK（细胞外信号调节激酶）结合，随后激活ERK激酶对c-Jun和cAMP反应元件结合蛋白（CREB）的活性。此外，18β-GA通过刺激核因子-红细胞相关因子2（Nrf2）激活脑源性神经营养因子（BDNF）转录，c-Jun,CREB,同时还在体外和体内抑制甲基CpG结合蛋白2（MeCP2）。在CSDS模型中，18β-GA的慢性腹膜内（i.p.）给药表现出预防性抗抑郁样作用，主要通过激活内侧前额叶皮层（mPFC）中的BDNF转录。有趣的是,通过在mPFC中参与BDNF-原肌球蛋白受体激酶B（TrkB）信号通路，单次腹膜内注射18β-GA在CSDS易感小鼠中产生了快速和持续的抗抑郁样作用。
结论：这些发现表明，mPFC中BDNF转录的激活是18β-GA抗抑郁样作用的基础，大脑中XYS的关键组成部分。
