Leojaponin inhibits NLRP3 inflammasome activation through restoration of autophagy via upregulating RAPTOR phosphorylation

Ethnopharmacological relevance Duan Teng Yimu decoction is a Chinese herbal medicine compound with proven therapeutic effects on inflammasome-related diseases, such as rheumatoid arthritis . This decoction consists of three Chinese herbal medicines, including Leonurus japonicus ( L. japonicus ), which promotes the blood circulation and exhibits detumescence activity, traditionally curing gynecologic and inflammasome diseases. Aim of the study To explore the anti-inflammasome activity and the underlying mechanisms of action of the compounds from L. japonicus . Materials and methods A series of compounds were isolated from L. japonicus . Their anti-inflammasome activities were evaluated in macrophages that were co-stimulated by lipopolysaccharide (LPS) and NLRP3 inflammasome inducers. NLRP3 inflammasome formation and apoptosis speck like containing a CARD (ASC) oligomerization were evaluated by immunofluorescent microscopy and Western blot analysis . The regulation of autophagy after treatment of this compound was also evaluated. Lastly, in vivo activity of Leojaponin was analyzed in a mouse acute gouty arthritis model. Results Here we show that Leojaponin, a diterpenoid compound from L. japonicus , suppressed lactate dehydrogenase and IL-1β release in Nigericin-stimulated macrophages in a pyroptosis model. Leojaponin inhibits NLRP3 inflammasome activation in both J774A.1 cells and bone marrow-derived macrophages in a dose dependent manner. Moreover, Leojaponin suppressed NLRP3-mediated ASC specks formation and ASC oligomerization. These activities of Leojaponin depend on restoration of autophagy via promoting RAPTOR phosphorylation. Furthermore, Leojaponin ameliorated monosodium urate (MSU)-induced acute gouty arthritis in vivo . Conclusion Our findings suggest that Leojaponin inhibits NLRP3 inflammasome activation through enhancing autophagy via RAPTOR phosphorylation, thereby highlighting Leojaponin as a potent drug for inflammasome-related diseases.