NIM5 series brain-penetrant NLRP3 inflammasome inhibitors suppress neuroinflammation in EAE and Alzheimer's models.

Abstract

Aberrant activation of the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome drives neuroinflammation in multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), and Alzheimer's disease (AD). No clinically approved CNS-active NLRP3 inhibitor exists, highlighting the need for brain-penetrant modulators. We report the discovery and characterization of a novel chemical scaffold of NLRP3 inhibitory modulators (NIM5 series) that selectively suppress inflammasome activation. Lead analogs potently inhibited interleukin-1β (IL-1β), caspase-1, and gasdermin D (GSDMD) activation in THP-1 cells (IC = 0.75 μM) without affecting NF-κB, NLRC4, or AIM2 signaling, as shown by immunoblotting and biophysical analyses. Mechanistic studies demonstrated direct NLRP3 binding, consistent with selective inhibition over NLRC4 and AIM2. Permeability assays demonstrated robust blood-brain barrier penetration and CNS availability in vitro. In vivo, systemic administration attenuated neuronal injury, improved behavioral outcomes, and reduced neuroinflammatory markers in both EAE and Aβ-induced mouse models. These findings establish a brain-penetrant NLRP3 inhibitor chemotype for CNS-targeted therapeutic development.