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

ABSTRACT

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-1ß 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.