Pharmacological targeting of the NLRP3 LRR domain with isothiazolinones overcomes CRID3-resistant inflammation

Area of Science:

• Immunology
• Drug Discovery
• Molecular Biology

Background:

• The NLRP3 inflammasome is implicated in numerous inflammatory, infectious, metabolic, and neurodegenerative diseases.
• Existing NLRP3 inhibitors like CRID3 have limitations, including inability to target certain hyperactive mutations and lack of clinical progression, necessitating novel therapeutic strategies.

Purpose of the Study:

• To identify and characterize novel selective inhibitors of the NLRP3 inflammasome.
• To explore new therapeutic avenues for NLRP3-driven inflammatory conditions.

Main Methods:

• High-throughput screening was employed to identify potential NLRP3 inhibitors.
• Biochemical assays were used to determine the binding domain and inhibitory mechanism of LOC14.
• In vivo studies in mouse models were conducted to evaluate the anti-inflammatory efficacy of LOC14.

Main Results:

• LOC14, an isothiazolinone-containing molecule, was identified as a selective NLRP3 inhibitor.
• Unlike CRID3, LOC14 binds to the LRR domain of NLRP3 and inhibits both CRID3-sensitive and resistant hyperactive variants.
• The carbonyl oxygen of the isothiazol-3(2H)-one moiety was found to be crucial for LOC14's inhibitory activity.
• LOC14 demonstrated significant anti-inflammatory effects in mouse models of colitis, sepsis, and psoriasis.

Conclusions:

• Isothiazolinone-containing compounds represent a promising class of selective NLRP3 inhibitors.
• LOC14 offers a novel mechanism of action and broad therapeutic potential for NLRP3-mediated inflammatory diseases.
• These findings provide a foundation for developing new therapies targeting the NLRP3 inflammasome.