Minoxidil hydrochloride impedes NLRP3 inflammasome activation via upregulation of AMPK-mediated autophagy

Abstract

NLRP3 inflammasome is a cytosolic multi-protein complex that plays a crucial role in the immune system, responding to various exogenous and endogenous stimuli by triggering protective inflammatory responses. However, aberrant NLRP3 inflammasome activation is implicated in numerous inflammatory diseases. Therefore, the NLRP3 inflammasome is an important pharmacological target for treating multiple diseases. In this context, we screened various US-FDA-approved drugs for NLRP3 inflammasome inhibition. We found that minoxidil hydrochloride (MXL) effectively inhibits the NLRP3 inflammasome, with IC50 values of 1.2 and 1.06 micron M for IL-1beta and IL-18 release, respectively, thereby protecting J774A.1 cells from inflammatory cell death. Similarly, anti-NLRP3 activity was confirmed in bone marrow-derived macrophages (BMDMs), where MXL was found to prevent ASC oligomerization, thereby inhibiting the NLRP3 inflammasome and leading to CASP1 cleavage. Further investigation revealed that MXL also utilizes AMPK-mediated autophagy to modulate NLRP3 inflammasome activity. Using siAMPK and bafilomycin A1, an end-stage autophagy inhibitor, we elucidated crosstalk between the NLRP3 inflammasome and autophagic pathways, which was modulated by MXL. Furthermore, we demonstrated the efficacy of MXL in two different mouse models of inflammation involving the NLRP3 inflammasome. MXL at doses of 10 and 20 mg/kg effectively inhibited the activation of NLRP3 inflammasome by monosodium urate in the air pouch model and by ATP in the peritoneal inflammation model, as evidenced by reduced secretion of IL-1{beta} and IL-18 in the lavage. Our study identifies MXL as a potent inhibitor of the NLRP3 inflammasome, warranting further investigation as a therapeutic agent for inflammatory diseases.