LMT2368 (1-(4-Chlorophenyl)-3-(3-fluoro-5-(trifluoromethyl)phenyl)urea) Negatively Regulates Inflammation by Inhibiting NLRP3 Inflammasome Activation.

Background/Objectives: The dysregulation of NLRP3 inflammasome activation has been established as a key driver of inflammatory disease pathology, which marks NLRP3 as an attractive therapeutic target. However, the clinical development of NLRP3 inhibitors such as MCC950 has been hampered by their associated toxicity profiles, highlighting an unmet clinical need. Methods: Herein, we present LMT2368, a novel urea-based NLRP3 inhibitor identified through screening of urea-based derivatives from our in-house compound library. Results: Biolayer interferometry confirmed direct binding of LMT2368 to the NLRP3 NACHT domain with a (K(D) = 27.4 ± 1.2 μM which was superior to MCC950. Molecular docking studies predicted enhanced binding interactions for LMT2368, consistent with its improved biological activity. In LPS-primed macrophages, LMT2368 dose-dependently suppressed IL-1β secretion (IC50 = 0.8 μM in J774A.1 cells) and caspase-1 activation without affecting NF-κB signaling. Importantly, LMT2368 inhibited ASC oligomerization and pyroptosis while maintaining excellent safety margins (CC50 > 50 μM). In a murine model of LPS-induced acute lung injury, LMT2368 (10 mg/kg) reduced bronchoalveolar lavage fluid immune cell infiltration by 68% (p < 0.001), suppressed pro-inflammatory cytokine release (IL-1β/IL-6/TNF-α), and preserved lung histoarchitecture. Notably, LMT2368 showed selectivity for NLRP3 inhibition without affecting TNF-α/IL-6 production during TLR4 priming in monocytic cell lines. Conclusions: Together, these findings establish LMT2368 as a promising lead compound for developing safer NLRP3 inhibitors with therapeutic potential for inflammasome-driven diseases.