The Role And Mechanism Of Manoalide In Inhibition Of NLRP3 Inflammasome And Alleviation Of Inflammatory Diseases

The NLRP3 inflammasome recognizes a variety of danger signals and its activation promotes the production of inflammatory cytokines,such as IL1β and IL-18.Thus,it plays a key role in the process of inflammation.In recent years,NLRP3 inflammasome has been reported to be involved in the occurrence and development of many major human diseases,such as neurodegenerative diseases,metabolic diseases,cardiovascular diseases,etc.Therefore,NLRP3 is also considered as an important intervention target for these diseases.At present,related studies have reported some inhibitors of the NLRP3 inflammasome,but there is no clinical drug targeting NLRP3.Therefore,further screening and identification of efficient and safe NLRP3 inflammasome inhibitors will help to discover disease interventions targeting NLRP3.Manoalide,first isolated from the sponge Luffariella variabilis,is a marine natureal sesterterpene and has potent anti-inflammatory effects.However,its antiinflammatory mechanism is still unclear.Our study found that manoalide significantly inhibits the activation of NLRP3 inflammasome in vivo and or vitro,and alleviates the occurrence and development of NLRP3-driven EAE.The main results are as follows:1.Manoalide inhibited NLRP3 inflammasome activation by multiple agonists and cLPS-induced non-canonical NLRP3 inflammasome activation in ain a dose-dependent manner.Also,manoalide effectively inhibited NLRP3 inflammasome activation in PBMC.Furthermore,Manoalide did not affect LPS-induced release of IL-6 and TNFa from BMDM and PBMC.2.Manoalide specifically inhibited the activation of NLRP3 inflammasome,but had no effect on the activation of AIM2,IPAF and Pyrin inflammasome.In addition,Manoalide did not affect the upregulation of NLRP3 inflammasome components in LPS-induced priming phase,nor did it affect LPS-activated NF-κB and MAPK signaling pathways.3.Manoalide did not affect the upstream events of NLRP3 inflammasome activation,including ion flux or mitochondrial dysfunction,and the inhibitory effect on the NLRP3 inflammasome was independent of the inhibition of PLA2 and PLC enzymatic activities.4.Manoalide blocked the NLRP3-NEK7 interaction,inhibited the assembly process of the NLRP3 inflammasome complex,thereby inhibited the activation of the NLRP3 inflammasome.5.Manoalide covalently bound to the lysine 377 of the NLRP3 NACHT domain.and manoalide did not bind to other inflammasome sensors,such as NLRP1b,AIM2 and NLRC4.6.Manoalide effectively reduced immune cell infiltration,inflammatory response and pathological demyelination in the central nervous system of EAE,thereby,alleviated the occurrence and development of EAE.Moreover,the therapeutic effect depends on the inhibition of the NLRP3 inflammasome.In conclusion,we found that manoalide specifically targets NLRP3 and inhibits inflammasome activation,and elucidated the mechanism by which it inhibits NLRP3 inflammasome activation.In addition,manoalide showed pretty therapeutic effect on EAE-induced neuroinflammation.Since manoalide has been approved in clinical trials for the treatment of psoriasis and showed high safety,our results suggest that manoalide or its analogs have potential application value in NLRP3 inflammasome-related diseases.