M464 inhibits activation of NLRP3 inflammasome and inflammatory response in mice.

Non-steroidal anti-inflammatory drugs (NSAIDs) function as antipyretic, analgesic and anti-inflammatory agents. However, its long application might result in gastrointestinal side effects. Therefore, it is imperative to hunt for novel and safer NSAIDs. Here, we report a new class of NSAIDs, M464, which was equipped with a hydrogen sulfide-releasing radical. We delved into its anti-inflammatory properties and underlying molecular mechanisms. In vitro, the relevance of the anti-inflammatory effects of M464 through the NLRP3 signaling pathway was explored by lactate dehydrogenase (LDH) release, WB (Western Blotting), ELISA assays and immunofluorescence experiments. In vivo, the influence and correlation of M464 on liver and lung tissue injury were investigated by means of histological evaluation, pathological analysis and serum index analysis. The correlation between M464 and NLRP3 signaling pathway in vivo injury model and its mechanism were investigated by Western Blotting and qPCR. In vitro results showed that M464 inactivates the assembly of the NLRP3 inflammasome, reduces the cleavage of Caspase-1 and the production of mature IL-1β, alleviates the generation of intracellular ROS, and decreases the oligomerization of the apoptosis-associated speck-like protein containing a CARD (ASC). In vivo results showed that M464 can down-regulate gene and protein expression levels of IL-1β and Caspase-1 in mice liver and lung injury models. M464 exhibits protective effects against acute lung and liver injury in mice, suggesting that M464 may be an alternative strategy to treat diseases driven by NLRP3 inflammasome activation.