Inhibition of RACK1-Mediated NLRP3 Oligomerization (Active Conformation) Ameliorates Acute Respiratory Distress Syndrome.

Summary

Chemoproteomics reveals that the sesquiterpene bigelovin covalently binds RACK1 at Cys168, disrupts RACK1–NLRP3 interactions, and blocks NLRP3 oligomerization across canonical, noncanonical, and alternative pathways. In murine models, bigelovin mitigated lung injury in LPS-induced ARDS and silicosis, positioning RACK1-mediated NLRP3 activation as a druggable anti-inflammatory node.

Key Findings

• Bigelovin inhibited NLRP3 inflammasome activation and cytokine release via canonical, noncanonical, and alternative pathways at nanomolar concentrations.
• Chemoproteomics identified covalent binding of bigelovin to RACK1 Cys168, disrupting RACK1–NLRP3 interaction and suppressing NLRP3 oligomerization in vitro and in vivo.
• In murine models, bigelovin treatment alleviated lung disease severity in LPS-induced ARDS and silicosis.
• Findings consolidate RACK1’s role in transitioning NLRP3 from auto-suppressed to active oligomeric states and nominate RACK1 as a druggable node.

Clinical Implications

Suggests a novel anti-inflammatory strategy for NLRP3-driven lung diseases, including ARDS; however, translation to humans will require safety, selectivity, and pharmacokinetic evaluation.

Limitations

• Preclinical models only; human validation is lacking.
• Selectivity, off-target effects, and safety of covalent RACK1 engagement remain uncharacterized.

Future Directions

Optimize bigelovin-derived covalent modulators for selectivity and PK/PD, validate in primary human lung cells and ex vivo tissues, and test efficacy in infectious ARDS models.