Nimbolide ameliorates ARDS and ulcerative colitis by disrupting NLRP3 inflammasome activation.

Summary

This preclinical study identifies Nimbolide as a selective NLRP3 inflammasome inhibitor that suppresses both NF-κB–dependent priming and inflammasome assembly by binding Lys565 in NLRP3. Nimbolide reduced Caspase-1 activation, IL-1β release, and pyroptosis in macrophages and improved pathology in LPS-induced ARDS and DSS-colitis mouse models, with efficacy dependent on NLRP3.

Key Findings

• Nimbolide dose-dependently inhibits NLRP3 inflammasome activation, blocking Caspase-1 cleavage, IL-1β release, and pyroptosis in macrophages.
• Nimbolide selectively targets NLRP3 (no significant inhibition of non-NLRP3 inflammasomes) and directly interacts with Lys565 in the NLRP3 NACHT domain.
• Nimbolide administration reduces inflammation and pathological damage in LPS-induced ARDS and DSS-induced ulcerative colitis models; effects are NLRP3-dependent (validated in Nlrp3-knockout mice).

Clinical Implications

Preclinical evidence supports Nimbolide as a candidate for development into an NLRP3-targeted therapy for ARDS and other NLRP3-driven inflammatory disorders; however, human safety, pharmacokinetics, and efficacy must be established before clinical application.

Limitations

• Preclinical study limited to murine models and macrophage/ cell assays; human cell and clinical data are lacking
• Pharmacokinetics, toxicity, dosing, and formulation for human use were not addressed

Future Directions

Optimize nimbolide analogs for potency/PK, perform GLP toxicity studies, test in human primary cells and ex vivo lung tissue, and advance to early-phase clinical trials for ARDS or other NLRP3-driven diseases.