Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Hefei 230032, China.
Department of Natural Medicine and Chemistry, School of Pharmacy, Anhui Medical University, Hefei 230032, China.
Int Immunopharmacol. 2021 Jul;96:107603. doi: 10.1016/j.intimp.2021.107603. Epub 2021 Apr 5.
We explored the effect of tetracyclic triterpenoid inonotsuoxide B (IB) extracts of Inonotus obliquus on M1 to M2 macrophage polarization and its possible underlying mechanism. Lipopolysaccharide (LPS)-activated M1 macrophages exert pro-inflammatory effects and release inflammatory cytokines including interleukin (IL)-1β and tumor necrosis factor (TNF)-α. The model and various groups were treated with different IB concentrations (2.5, 5, and 10 μg/mL) to observe changes in the M1 and M2 phenotypes, gene expression of NAD-dependent deacetylase sirtuin-1 (Sirt1), and endoplasmic reticulum stress (ERS). SIRT1-siRNA and thapsigargin (TG), an ERS agonist, were used to examine the relationship between SIRT1/ERS and the effect of IB on M1 to M2 RAW264.7 macrophage phenotypic changes. We found that IB had no effect on RAW264.7 cell proliferation at 10 μg/mL. Increasing concentrations of IB (2.5, 5, and 10 μg/mL) decreased the number of phenotypic M1 macrophages and, consequently, decreased the release of the inflammatory cytokines, IL-1β and TNF-α. Furthermore, IB treatment increased the level of phenotypic M2 macrophages, which increased the release of anti-inflammatory cytokines such as arginase (Arg)-1 and found in inflammatory zone 1 (FIZZ1) in a dose-dependent manner. Further, we found that IB increased the expression of SIRT1 and inhibited that of ERS. Inhibition of Sirt1 expression by siRNA significantly increased that of ERS marker genes and IL1β. Excessive ERS levels inhibited the IB-induced transformation of phenotypic M1 macrophage to the M2 macrophage phenotype. Therefore, IB, an extract of I. obliquus, may regulate macrophage polarization through the SIRT1/ERS signaling pathway.
我们探讨了从斜盖灵芝（Inonotus obliquus）中提取的五环三萜类化合物 inonotsuoxide B（IB）对 M1 向 M2 巨噬细胞极化的影响及其可能的作用机制。脂多糖（LPS）激活的 M1 巨噬细胞发挥促炎作用，并释放包括白细胞介素（IL）-1β和肿瘤坏死因子（TNF）-α在内的炎症细胞因子。该模型和各个组用不同浓度的 IB（2.5、5 和 10μg/mL）处理，以观察 M1 和 M2 表型的变化、NAD 依赖性去乙酰化酶沉默调节因子 1（Sirt1）的基因表达和内质网应激（ERS）。用 SIRT1-siRNA 和内质网应激激动剂 thapsigargin（TG）来检测 SIRT1/ERS 与 IB 对 M1 向 M2 RAW264.7 巨噬细胞表型变化的影响之间的关系。我们发现，IB 在 10μg/mL 时对 RAW264.7 细胞的增殖没有影响。随着 IB 浓度的增加（2.5、5 和 10μg/mL），表型 M1 巨噬细胞的数量减少，相应地，炎症细胞因子 IL-1β 和 TNF-α的释放减少。此外，IB 处理增加了表型 M2 巨噬细胞的数量，从而以剂量依赖性方式增加了抗炎细胞因子如精氨酸酶（Arg）-1 和炎症区域 1（FIZZ1）的释放。进一步，我们发现 IB 增加了 SIRT1 的表达并抑制了 ERS 的表达。用 siRNA 抑制 Sirt1 表达显著增加了 ERS 标记基因和 IL1β 的表达。过度的 ERS 水平抑制了 IB 诱导的表型 M1 巨噬细胞向 M2 巨噬细胞表型的转化。因此，IB，一种斜盖灵芝提取物，可能通过 SIRT1/ERS 信号通路调节巨噬细胞极化。
