Steroid Constituents of Solidago canadensis alleviate LPS-induced inflammation via AMPK regulated Mitophagy/NLRP3 and NF-κB pathway.

Abstract

Inflammation is a major risk factor for a variety of human diseases, such as sepsis, Inflammatory Bowel Disease (IBD) and also major cardiovascular disease including atherosclerosis. Solidago canadensis is used as a traditional medicine to treat inflammation-related diseases. However, the component with anti-inflammatory activity of Solidago canadensis is not clear. In this study, we aimed to search for new bioactive steroids from Solidago canadensis and investigate their anti-inflammatory activity both in vitro and in vivo. Lipopolysaccharides (LPS)-stimulated RAW264.7 cells, mouse bone marrow-derived macrophages (BMDMs) and peripheral blood mononuclear cells (PBMCs) were used to induce an inflammation response. Compound 10 outperformed other compounds for superior anti-inflammatory activity and significant inhibition of NLR family, pyrin domain containing 3 (NLRP3) inflammasome activation. Mechanistically, compound 10 induced mitophagy by activating AMP-activated protein kinas (AMPK) to suppress NLRP3 inflammasome activation. Inhibiting AMPK by inhibitor BML-275 significantly attenuated compound 10 induced mitophagy and subsequent the NLRP3 inflammasome. Besides, the NF-κB activation, key step in NLRP3 inflammasome priming, was also suppressed by compound 10 via activation of AMPK. In addition, the in vivo experiments showed that compound 10 could alleviate LPS-induced inflammatory and dextran sulfate sodium salt -induced colitis in C57BL/6 mice. Collectively, the present study, for the first time, shows that the steroids compound 10 exhibited anti-inflammatory effect via AMPK/mitophagy/NLRP3 as well as AMPK/NF-κB/NLRP3 signaling pathway, which strongly suggests the therapeutic potential of compound 10 in various inflammatory diseases.