College of Pharmacy, Beihua University, Jilin, Jilin Province 132013, PR China.
School of Pharmacy and Medicine, Tonghua Normal University, Tonghua, Jilin Province, 134001, PR China.
J Ethnopharmacol. 2024 Dec 5;335:118646. doi: 10.1016/j.jep.2024.118646. Epub 2024 Aug 2.
Ligustrum lucidum W.T. Aiton is a traditional Chinese medicine that has long been used with high hepatoprotective therapeutic and condition value. Specnuezhenide (SP), the standard prominent secoiridoid compound of Fructus Ligustri Lucidi may ameliorate hepatic inflammation in chronic liver diseases.
Regulating inflammation through SIRT6-P2X7R axis has caused the emergence of novel molecular mechanism strategies for reversing hepatic fibrosis. This study focused on the mechanism of SP in modulating the liver inflammatory microenvironment in hepatic fibrosis.
C57BL/6 mice with hepatic fibrosis were stimulated with thioacetamide (TAA) prior to administration of SP. Hepatic stellate cells (HSCs) or normal mouse primary hepatocytes were exposed to transforming growth factor-β (TGF-β) treatment. Meanwhile, normal mouse bone marrow-derived macrophages (BMDMs) were treated with lipopolysaccharide/adenosine triphosphate (LPS/ATP), aiming to obtain the conditioned medium. HSCs and hepatocytes were transfected with SIRT6 knockdown vector (siRNA-SIRT6) to estimate the impact of SP on the SIRT6-P2X7R/NLRP3 signaling pathway.
SP suppressed the HSCs extracellular matrix (ECM) deposition as well as pro-inflammatory cytokine levels induced by the medium of BMDMs or TGF-β. In addition, SP also significantly up-regulated SIRT6, inhibited P2X7R-NLRP3 inflammasome in HSCs and hepatocytes, and functioned as MDL-800 (a SIRT6 agonist). SP reduced the hepatocytes pyroptosis and further prevented the occurrence of inflammatory response in the liver. SP could inhibit the activation of BMDMs and impede IL-1β and IL-18 from entering extracellular regions. Moreover, deficiency of SIRT6 in HSCs or hepatocytes reduced SP's regulation of P2X7R suppression. For TAA-treated mice, SP mitigated histopathological changes, ECM accumulation, EMT process, and NETs formation in hepatic fibrosis.
Therefore, SP decreased inflammatory response via SIRT6-P2X7R/NLRP3 pathway and suppressed fibrillogenesis. These findings supported SP as the novel candidate to treat hepatic fibrosis.
女贞子（Ligustrum lucidum W.T. Aiton）是一种传统中药，具有长期的高保肝治疗和调理价值。冬绿苷（SP）是女贞子的标准突出的环烯醚萜类化合物，可能改善慢性肝病中的肝炎症。
通过 SIRT6-P2X7R 轴调节炎症已经为逆转肝纤维化的新型分子机制策略的出现创造了条件。本研究侧重于 SP 调节肝纤维化中肝炎症微环境的机制。
用硫代乙酰胺（TAA）刺激肝纤维化 C57BL/6 小鼠，然后给予 SP 处理。将肝星状细胞（HSCs）或正常小鼠原代肝细胞暴露于转化生长因子-β（TGF-β）处理下。同时，用脂多糖/三磷酸腺苷（LPS/ATP）处理正常小鼠骨髓来源的巨噬细胞（BMDMs），以获得条件培养基。用 SIRT6 敲低载体（siRNA-SIRT6）转染 HSCs 和肝细胞，以评估 SP 对 SIRT6-P2X7R/NLRP3 信号通路的影响。
SP 抑制了由 BMDMs 或 TGF-β 诱导的 HSCs 细胞外基质（ECM）沉积和促炎细胞因子水平。此外，SP 还显著上调了 SIRT6，抑制了 HSCs 和肝细胞中的 P2X7R-NLRP3 炎性小体，作用类似于 MDL-800（SIRT6 激动剂）。SP 减少了肝细胞焦亡，并进一步防止了肝脏中的炎症反应发生。SP 可抑制 BMDMs 的激活，并阻止 IL-1β和 IL-18 进入细胞外区域。此外，HSCs 或肝细胞中的 SIRT6 缺失降低了 SP 对 P2X7R 抑制的调节作用。对于 TAA 处理的小鼠，SP 减轻了肝纤维化中的组织病理学变化、ECM 积累、EMT 过程和 NETs 形成。
因此，SP 通过 SIRT6-P2X7R/NLRP3 途径减少炎症反应，并抑制纤维形成。这些发现支持 SP 作为治疗肝纤维化的新型候选药物。
