State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, China.
Front Immunol. 2023 Aug 4;14:1206513. doi: 10.3389/fimmu.2023.1206513. eCollection 2023.
Neuroinflammation has been reported as a potential contributing factor to brain diseases, and is characterized by activated microglia with release of multiple inflammatory mediators. 2,3,5,6-Tetramethylpyrazine (TMP) is an active alkaloid in Hort. and has various biological activities, including anti-inflammatory and neuroprotection properties. However, the anti-neuroinflammatory activity of TMP has been less studied and its potential molecular mechanisms in this field remain unclear. This study aimed to investigate the effects of TMP and its underlying mechanisms in neuroinflammation.
, lipopolysaccharide (LPS)-stimulated BV2 microglia were used to assess the effects of TMP on inflammatory cytokines as well as the components of the SIRT1/NF-κB signaling pathway, which were measured by using ELISA, western blotting, qRT-qPCR and immunofluorescence. Moreover, LPS-induced acute neuroinflammation model in mice was performed to detect whether TMP could exert anti-neuroinflammatory effects , and the EX527, a SIRT1 inhibitor, were given intraperitoneally every two days prior to TMP treatment. Serums and spinal trigeminal nucleus (Sp5) tissues were collected for ELISA assay, and the Sp5 tissues were used for HE staining, Nissl staining, immunofluorescence, qRT-PCR and western blotting.
, TMP treatment significantly reduced the secretion of pro-inflammatory cytokines, including TNF-α and IL-6, promoted SIRT1 protein expression and inactivated NF-κB signaling pathway in LPS-induced neuroinflammation. Interestingly, pretreatment with EX527 blocked the therapeutic effects of TMP on neuroinflammation . Furthermore, TMP reduced the levels of pro-inflammatory cytokines and chemokines, and prevented microglia from polarizing towards a pro-inflammatory state through activating SIRT1 and inhibiting NF-κB activation in LPS-induced neuroinflammation in mice. And EX527 reversed the beneficial effects of TMP against LPS exposure in mice.
In summary, this study unravels that TMP could mitigate LPS-induced neuroinflammation via SIRT1/NF-κB signaling pathway.
神经炎症已被报道为导致脑部疾病的潜在因素之一，其特征为小胶质细胞激活并释放多种炎症介质。2,3,5,6-四甲基吡嗪（TMP）是川芎中的一种活性生物碱，具有多种生物学活性，包括抗炎和神经保护作用。然而，TMP 的抗神经炎症活性研究较少，其在该领域的潜在分子机制尚不清楚。本研究旨在探讨 TMP 的作用及其在神经炎症中的潜在机制。
采用脂多糖（LPS）刺激的 BV2 小胶质细胞评估 TMP 对炎症细胞因子以及 SIRT1/NF-κB 信号通路组成成分的影响，采用 ELISA、western blot、qRT-qPCR 和免疫荧光法进行检测。此外，采用 LPS 诱导的急性神经炎症模型检测 TMP 是否具有抗神经炎症作用，在 TMP 处理前每两天腹腔内给予 LPS 诱导的急性神经炎症模型 EX527（一种 SIRT1 抑制剂）。收集血清和三叉神经脊束核（Sp5）组织进行 ELISA 检测，Sp5 组织用于 HE 染色、尼氏染色、免疫荧光、qRT-PCR 和 western blot。
TMP 治疗可显著降低 LPS 诱导的神经炎症中小胶质细胞分泌的促炎细胞因子 TNF-α 和 IL-6，促进 SIRT1 蛋白表达并抑制 NF-κB 信号通路。有趣的是，EX527 预处理可阻断 TMP 对神经炎症的治疗作用。此外，TMP 通过激活 SIRT1 抑制 NF-κB 激活，可降低 LPS 诱导的神经炎症中小胶质细胞向促炎状态极化所产生的促炎细胞因子和趋化因子水平，EX527 可逆转 TMP 对 LPS 暴露的有益作用。
综上所述，本研究揭示了 TMP 可通过 SIRT1/NF-κB 信号通路减轻 LPS 诱导的神经炎症。
