Jin-Fang Luo

, TNF-α, and IL-6 in LPS-stimulated THP-1 macrophages. Furthermore, DC inhibited the macrophage M1 phenotype and the production of reactive oxygen species (ROS) in LPS-activated RAW264.7 cells. Mechanism studies showed that DC mainly activated nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, increased the level of anti-oxidant protein heme oxygenase-1 (HO-1) and thus produced the anti-inflammatory and anti-oxidant effects, which were abolished by Nrf2 siRNA and HO-1 inhibitor. These findings suggested that DC could be a new Nrf2 activator for the treatment and prevention of diseases related to inflammation and oxidative stress.

Sinomenine (SIN), an alkaloid derived from the plant Sinomenium acutum, has anti-inflammatory and analgesic effects and has been used for rheumatoid arthritis treatment in China. This study aims to verify the hypothesis that SIN acts on α7 nicotinic acetylcholine receptor (α7nAChR) to inhibit the activation of macrophages stimulated by lipopolysaccharide. The prototypical α7nAChR antagonist α-bungarotoxin and mecamylamine attenuated the effect of SIN on tumor necrosis factor-α and interleukin-6 in RAW264.7 murine macrophage-like cells and primary peritoneal macrophages of mouse induced by lipopolysaccharide. With the knockdown of α7nAChR expression in RAW264.7 cells by small interfering RNA, the inhibitory effect of SIN on tumor necrosis factor-α and interleukin-6 was reversed. Sinomenine decreased p65 expression in nuclear and increased IκBα expression in cytoplasm, and these effects were reversed by the α7nAChR small interfering RNA as well. These results indicate that the anti-inflammatory effects of SIN on macrophages in vitro depend on α7nAChR.

Objective: To investigate the cellular mechanism that sinomenine (SIN) inhibits inflammation in macrophages induced by LPS through α7 nicotinic acetylcholine receptor (α7nAChR).Materials and methods: RAW264.7 cells were stimulated with LPS and treated by SIN or nicotine (Nic). A selective antagonist of α7nAChR, α-bungarotoxin (BTX) was used to block α7nAChR. AG490 was used to inhibit JAK2 activation. ELISA was performed to detect the levels of TNF-α and MCP-1. Western blotting was used to analyze the expression of MIF, MMP-9, CD14, TLR4, STAT3 and p-STAT3. Intracellular-free calcium level was measured by Fluorescent probe fluo-3/AMResults: SIN inhibited the production of TNF-α, MCP-1, MIF, and MMP-9, decreased the expression of CD14 and TLR4, and inhibited the release of intracellular-free calcium from intracellular stores in RAW 264.7 cells stimulated by LPS. JAK-specific inhibitor AG490 attenuated the inhibitory effect of SIN on TNF-α. SIN increased the phosphorylation of STAT3. And the above effects of SIN were attenuated by antagonist of α7nAChR.Conclusions: SIN can decrease the expression of CD14/TLR4 and intracellular free calcium level, activate JAK2/STAT3 pathway to inhibit inflammatory response through α7nAChR in macrophages.