Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, P.R. China.
Inner Mongolia Key Laboratory of Mongolian Medicine Pharmacology for Cardio-Cerebral Vascular System, Tongliao, Inner Mongolia, P.R. China.
PLoS One. 2021 May 26;16(5):e0251578. doi: 10.1371/journal.pone.0251578. eCollection 2021.
Ethyl ferulate (EF) is a derivative of ferulic acid (FA), which is a monomeric component purified from the traditional medicinal herb Ferula, but its effects have not been clear yet. The purpose of this study was to evaluate whether EF can reduce inflammation levels in macrophages by regulating the Nrf2-HO-1 and NF-кB pathway.
The LPS-induced raw 264.7 macrophage cells model was used to determine the anti-inflammatory and anti-oxidative stress effects of EF. The levels of IL-1β, IL-6, TNF-α and PGE2 were analyzed by ELISA. The mRNA and protein of COX-2, iNOS, TNF-α, IL-6, HO-1 and Nrf2 were identified by RT-PCR analysis and western blotting. Intracellular ROS levels were assessed with DCFH oxidation staining. The expressions of NF-кB p-p65 and Nrf2 were analyzed by immunofluorescence assay. The inhibitory effect of Nrf2 inhibitor ML385 (2μM) on mediatation of antioxidant activity by raw 264.7 macrophage cells was evaluated. The effect of EF was confirmed in acute lung injury mice model.
In our research, EF reduced the expression of iNOS, COX2 and the production of PGE2. EF could inhibit the production of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) in lipopolysaccharide (LPS) stimulated macrophages and decreased expression of IL-6 and TNF-α in LPS stimulated macrophages. Furthermore, EF inhibited NF-кB p65 from transporting to the nucleus, decreased the expression of p-IкBα, significantly decreased the level of intracellular reactive oxygen species (ROS) and activated Nrf2/HO-1 pathways. EF could attenuate the degree of leukocyte infiltration, reduced MPO activity, mRNA levels and secretion of TNF-α and IL-6 in vivo. EF exhibited potent protective effects against LPS-induced acute lung injury in mice.
Collectively, our data showed that EF relieved LPS-induced inflammatory responses by inhibiting NF-κB pathway and activating Nrf2/HO-1 pathway, known to be involved in the regulation of inflammatory responses by Nrf2.
阿魏酸乙酯（EF）是阿魏酸（FA）的一种衍生物，FA 是从传统草药当归中提取的单体成分，但 EF 的作用尚不清楚。本研究旨在评估 EF 是否可以通过调节 Nrf2-HO-1 和 NF-κB 通路来降低巨噬细胞中的炎症水平。
采用 LPS 诱导的 RAW264.7 巨噬细胞模型，测定 EF 的抗炎和抗氧化应激作用。通过 ELISA 分析 IL-1β、IL-6、TNF-α 和 PGE2 的水平。采用 RT-PCR 分析和 Western blot 鉴定 COX-2、iNOS、TNF-α、IL-6、HO-1 和 Nrf2 的 mRNA 和蛋白。通过 DCFH 氧化染色评估细胞内 ROS 水平。通过免疫荧光分析评估 NF-κB p-p65 和 Nrf2 的表达。通过 Nrf2 抑制剂 ML385（2μM）评估其对 RAW264.7 巨噬细胞抗氧化活性的调节作用。并在急性肺损伤小鼠模型中验证 EF 的作用。
在本研究中，EF 降低了 iNOS、COX2 的表达和 PGE2 的产生。EF 可抑制脂多糖（LPS）刺激的巨噬细胞中促炎细胞因子（IL-1β、IL-6 和 TNF-α）的产生，并降低 LPS 刺激的巨噬细胞中 IL-6 和 TNF-α 的表达。此外，EF 抑制 NF-κB p65 向核内转运，减少 p-IκBα 的表达，显著降低细胞内活性氧（ROS）水平，并激活 Nrf2/HO-1 通路。EF 可减轻白细胞浸润程度，降低 MPO 活性，降低 TNF-α 和 IL-6 的 mRNA 水平和分泌量。EF 对 LPS 诱导的急性肺损伤小鼠具有显著的保护作用。
总之，我们的数据表明，EF 通过抑制 NF-κB 通路和激活 Nrf2/HO-1 通路缓解 LPS 诱导的炎症反应，已知 Nrf2 参与炎症反应的调节。
