Novel chemotype NLRP3 inhibitors that target the CRID3-binding pocket with high potency.

The NLRP3 inflammasome plays a central role in various human diseases. Despite significant interest, most clinical-grade NLRP3 inhibitors are derived from sulfonylurea inhibitor CRID3 (also called MCC950). Here, we describe a novel chemical class of NLRP3-inhibiting compounds (NIC) that exhibit potent and selective NLRP3 inflammasome inhibition in human monocytes and mouse macrophages. BRET assays demonstrate that they physically interact with NLRP3. Structural modeling further reveals they occupy the same binding site of CRID3 but in a critically different conformation. Furthermore, we show that NIC-11 and NIC-12 lack the off-target activity of CRID3 against the enzymatic activity of carbonic anhydrases I and II. NIC-12 selectively reduces circulating IL-1ß levels in the LPS-endotoxemia model in mice and inhibits NLRP3 inflammasome activation in CAPS patient monocytes and mouse macrophages with about tenfold increased potency compared with CRID3. Altogether, this study unveils a new chemical class of highly potent and selective NLRP3-targeted inhibitors with a well-defined molecular mechanism to complement existing CRID3-based NLRP3 inhibitors in pharmacological studies and serve as novel chemical leads for the development of NLRP3-targeted therapies.