Identification of NLRP3PYD Homo-Oligomerization Inhibitors with Anti-Inflammatory Activity

Abstract

Inflammasomes are multiprotein complexes that represent critical elements of the inflammatory response. The dysregulation of the best-characterized complex, the NLRP3 inflammasome, has been linked to the pathogenesis of diseases such as multiple sclerosis, type 2 diabetes mellitus, Alzheimer’s disease, and cancer. While there exist molecular inhibitors specific for the various components of inflammasome complexes, no currently reported inhibitors specifically target NLRP3PYD homo-oligomerization. In the present study, we describe the identification of QM380 and QM381 as NLRP3PYD homo-oligomerization inhibitors after screening small molecules from the MyriaScreen library using a split-luciferase complementation assay. Our results demonstrate that these NLRP3PYD inhibitors interfere with ASC speck formation, inhibit pro-inflammatory cytokine IL1-β release, and decrease pyroptotic cell death. We employed spectroscopic techniques and computational docking analyses with QM380 and QM381 and the PYD domain to confirm the experimental results and predict possible mechanisms underlying the inhibition of NLRP3PYD homo-interactions.

Structural Mechanisms of NLRP3 Inflammasome Assembly and Activation

“…LRR domains mainly mediate protein-protein interactions, and the LRR of NLRP3 has also been implicated in maintaining NLRP3's stability. NACHT domains, which possess the ability to bind nucleotides and hydrolyze ATP, once triggered, may go through ATP-dependent selfoligomerization resulting in self-PYD interactions that further recruit ASC, the adaptor (6,11,20,(23)(24)(25)(26) (Figure 1b,c).…”

Portrayal of NLRP3 Inflammasome in Atherosclerosis: Current Knowledge and Therapeutic Targets

“…The priming process involves the recognition of PAMPs and DAMPs by PRRs (TLRs, TL-1Rs, and cytokine receptors) followed by the activation of nuclear factor-κB (NF-κB), resulting in transcriptional activation of NLRP3, pro-IL-1β, pro-IL-18 and structural protein shifts, such as ASC phosphorylation and de-ubiquitination of NLRP3 [16,38]. The activation step involves NLRP3 oligomerization and NLRP3, ASC, and pro-caspase-1 complex formation, prompting caspase-1 activation as well as IL-1β and IL-18 generation [39].…”

Molecular Mechanisms of Inflammasome in Ischemic Stroke Pathogenesis

“…The NLRP3 inflammasome pathway is also modulated by long non-coding RNA XLOc_000647 [ 102 ] and numerous microRNAs such as mir 132 [ 103 ], and mir 22 [ 104 ]. The term miRNAs (microRNAs) refers to 22 nucleotides (nt) non-protein-coding RNAs capable of targeting mRNAs to inhibit translation, degradation, or cleavage.…”