College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha 410208, China; College of Clinical Medicine, Hunan University of Chinese Medicine, Changsha 410208, China.
Center for Medical Research and Innovation, The First Hospital of Hunan University of Chinese Medicine, Changsha 410002, China.
Int Immunopharmacol. 2024 Mar 30;130:111749. doi: 10.1016/j.intimp.2024.111749. Epub 2024 Mar 1.
Saikosaponin F (SsF) is one of the major active ingredients of Radix Bupleuri, an herb widely used in the treatment of depression. Studies have shown that dry eye disease often occurs together with depression. The aim of this study is to investigate whether SsF can improve depression-associated dry eye disease and explore the underlying mechanism.
Behavioral test was used to verify the effect of SsF on CUMS-induced depression-like behaviors in mice. Corneal fluorescein staining, phenol red cotton thread test and periodic acid-Schiff (PAS) staining were used to observe the effect of SsF on depression-associated dry eye disease. Western blot (WB) was performed to observe the expression of TAK1 protein and key proteins of NF-κB and MAPK (P38) inflammatory pathways in the hippocampus and cornea. Immunohistochemical staining was used to observe the expression of microglia, and immunoprecipitation was used to observe K63-linked TAK1 ubiquitination. Subsequently, we constructed a viral vector sh-TAK1 to silence TAK1 protein to verify whether SsF exerted its therapeutic effect based on TAK1. The expression of inflammatory factors such as IL-1β, TNF-α and IL-18 in hippocampus and cornea were detected by ELISA. Overexpression of TRIM8 (OE-TRIM8) by viral vector was used to verify whether SsF improved depression-associated dry eye disease based on TRIM8.
SsF treatment significantly improved the depression-like behavior, increased tear production and restored corneal injury in depression-related dry eye model mice. SsF treatment downregulated TAK1 expression and TRIM8-induced K63-linked TAK1 polyubiquitination, while inhibiting the activation of NF-κB and MAPK (P38) inflammatory pathways and microglial expression. In addition, selective inhibition of TAK1 expression ameliorated depression-associated dry eye disease, while overexpression of TRIM8 attenuated the therapeutic effect of SsF on depression-associated dry eye disease.
SsF inhibited the polyubiquitination of TAK1 by acting on TRIM8, resulting in the downregulation of TAK1 expression, inhibition of inflammatory response, and improvement of CUMS-induced depression-associated dry eye disease.
柴胡皂苷 F（SsF）是柴胡这一广泛用于治疗抑郁症的草药中的主要活性成分之一。研究表明，干眼症常与抑郁症同时发生。本研究旨在探讨 SsF 是否能改善与抑郁相关的干眼症，并探讨其潜在机制。
采用行为学测试验证 SsF 对 CUMS 诱导的抑郁样行为小鼠的作用。通过角膜荧光素染色、酚红棉线试验和过碘酸雪夫（PAS）染色观察 SsF 对与抑郁相关的干眼症的影响。通过 Western blot（WB）观察 SsF 对海马和角膜中 TAK1 蛋白及 NF-κB 和 MAPK（P38）炎症通路关键蛋白表达的影响。免疫组织化学染色观察小胶质细胞的表达，免疫沉淀观察 K63 连接的 TAK1 泛素化。随后，我们构建了一种病毒载体 sh-TAK1 来沉默 TAK1 蛋白，以验证 SsF 是否基于 TAK1 发挥其治疗作用。通过 ELISA 检测海马和角膜中炎症因子如 IL-1β、TNF-α和 IL-18 的表达。通过病毒载体过表达 TRIM8（OE-TRIM8）来验证 SsF 是否基于 TRIM8 改善与抑郁相关的干眼症。
SsF 治疗显著改善了抑郁样行为，增加了泪液分泌，恢复了与抑郁相关的干眼症模型小鼠的角膜损伤。SsF 治疗下调了 TAK1 表达和 TRIM8 诱导的 K63 连接的 TAK1 多泛素化，同时抑制了 NF-κB 和 MAPK（P38）炎症通路和小胶质细胞表达的激活。此外，选择性抑制 TAK1 表达可改善与抑郁相关的干眼症，而过表达 TRIM8 则减弱了 SsF 对与抑郁相关的干眼症的治疗作用。
SsF 通过作用于 TRIM8 抑制了 TAK1 的多泛素化，导致 TAK1 表达下调、抑制炎症反应，并改善了 CUMS 诱导的与抑郁相关的干眼症。
