Recent Progress and Prospects of Small Molecules for NLRP3 Inflammasome Inhibition

Abstract

NLRP3 inflammasome is a multiprotein complex involved in host immune response�which exerts various biological effects by mediating the maturation and secretion of IL-1β and IL-18�and pyroptosis. However, its aberrant activation could cause amplification of inflammatory effects, thereby triggering a range of ailments, including Alzheimer's disease, Parkinson's disease, rheumatoid arthritis, gout, type 2 diabetes mellitus, and cancer. For the past few years, as an attractive anti-inflammatory target, NLRP3-targeting small-molecule inhibitors have been widely reported by both the academic and the industrial communities. In order to deeply understand the advancement of NLRP3 inflammasome inhibitors, we provide comprehensive insights and commentary on drugs currently under clinical investigation, as well as other NLRP3 inflammasome inhibitors from a chemical structure point of view, with an aim to provide new insights for the further development of clinical drugs for NLRP3 inflammasome-mediated diseases. ■ SIGNIFICANCE• Abnormal activation of NLRP3 inflammasome has been implicated in various human diseases. • Therefore, the development of inhibitors targeting the NLRP3 inflammasome holds significant importance. • This perspective highlights the opportunities and challenges in the development of current NLRP3targeting inhibitors and provides novel insights for future drug discovery targeting NLRP3.

Pharmacological Analysis of NLRP3 Inflammasome Inhibitor Sodium [(1,2,3,5,6,7-Hexahydro-s-indacen-4-yl)carbamoyl][(1-methyl-1H-pyrazol-4-yl)({[(2S)-oxolan-2-yl]methyl})sulfamoyl]azanide in Cellular and Mouse Models of Inflammation Provides a Translational Framework

“…Total cell numbers were determined using a hemacytometer and adjusted to 2.6 × 10 6 cells/mL in RPMI GlutaMAX medium containing 1% FBS, 1% penicillin/streptomycin, and 20 mM HEPES, pH 7.3. The LPS/ATP challenge assay was conducted as previously detailed . Briefly, 0.1 mL (2.6 × 10 5 cells) of the PBMC suspension was added to each well of 96-well plates.…”

“…Heparin-stabilized blood from healthy volunteers was subjected to a 2-step activation protocol as previously described. , Blood samples were diluted with RPMI GlutaMAX medium containing 20 mM HEPES, pH 7.3 (2 parts blood to 1 part medium), after which 0.14 mL of the diluted samples were placed in individual wells of a 96-well plate designated not to receive LPS. To the remaining diluted blood sample, an appropriate volume of 1 μg/mL LPS was added to achieve a final concentration of 100 ng/mL.…”

“…The search for small molecule therapeutics to harness NLRP3 activation began in earnest following the realization that a previously identified inhibitor of IL-1β post-translational processing (CP-456,773) is a selective inhibitor of NLRP3 activation. , CP-456,773 originally was advanced into clinical trials, but its development was halted due to liver safety concerns . Recent biochemical, cryo-EM, and X-ray crystallography studies identified CP-456,773 and structural analogues as binding directly to the NACHT domain of NLRP3. − A new wave of directed medicinal chemistry efforts have led to the discovery of novel chemotypes (recently reveiwed , ), including a series of carboxylate esters, which are highly effective inhibitors of human monocyte NLRP3-induced IL-1β output . Clinical trials are now underway to evaluate the pharmacokinetics and pharmacodynamics of this new generation of small molecule inhibitors of NLRP3 activation. − One such candidate, GDC-2394, contained a sulfonylurea core as found in CP-456,773 and was also found to carry liver safety concerns when administered at a high dose to healthy volunteers .…”

Discovery of Potent, Orally Bioavailable, Tricyclic NLRP3 Inhibitors

“…In addition, IL-1β has been shown to play an important role in chronic diseases such as gout or type 2 diabetes as well as in neuroinflammatory disorders including multiple sclerosis, Alzheimer’s disease, or diabetic neuropathy. − Moreover, the CANTOS study, a secondary risk prevention study in cardiovascular disease with the IL-1β monoclonal antibody canakinumab, has shown that IL-1β contributes to cardiovascular risk, lung cancer, and osteoarthritis. − NLRP3, as the main inflammasome sensor for sterile danger signals associated with many of these diseases, has become an attractive therapeutic target for low-molecular-weight drug discovery, with the potential to inhibit IL-1β, IL-18, and pyroptosis, and penetrate tissues inaccessible to biologics . The publication of MCC950 (also known as CP-456,773 or CRID3), as a bona fide NLRP3 inhibitor, and the subsequent confirmation of its direct binding to the NLRP3 NACHT domain by biochemical methods and crystallography, have allowed for a first wave of MCC950 -derived NLRP3 inhibitors such as ZYIL1 , GDC-2394 , and NT-0796 (Figure ) to enter early clinical development. − These compounds have potential liabilities, including liver toxicity, , so broader chemical diversity is needed to maximize chances of developing a safe and efficacious NLRP3 inhibitor. In this paper, we describe the discovery of tricyclic NLRP3 inhibitors which have been optimized from an initial screening hit to an advanced preclinical candidate.…”

Local Scaffold Diversity-Contributed Generator for Discovering Potential NLRP3 Inhibitors

“…17 MCC950 is the well-known NLRP3 inhibitor. 18 Recent years, a large number of MCC950 analogs 19 have emerged while given the limited number of inhibitors in clinical trials, thus it is of great significance to develop novel inhibitors of NLRP3. Designing NLRP3 inhibitors is challenging with conventional drug design methods.…”