RM1mAb avoids Intracellular degradation to Synergistically inhibit NLRP3 Inflammasome Activation in Familial Cold Autoinflammatory Syndrome.

The NLRP3 inflammasome enables release of mitochondrial DNA to circulation. Circulating oxidized mitochondrial DNA generated in response to NLRP3 inflammasome activation functions as an alarmin that contributes to the maintenance of systemic inflammation. The discovery that NLRP3 could cleave oxidized mtDNA led to repurposed chemical inhibitors that dually target NLRP3 and DNA glycosylase OGG1, resulting in pro-survival type-1 interferon. Using molecular dynamics and immunology we show that RM1mAb, a full-length monoclonal antibody targeting the NLRP3 pyrin domain, can prevent NLRP3 from interacting with mitochondrial DNA. We further illustrate RM1mAb can exploit FCγRs for cell entry and avoid destruction by the lysosomal pathway to inhibit IL-1β secretion in peripheral mononuclear blood cells (PBMCs) isolated from patients with Familial Cold Autoinflammatory Syndrome harboring NLRP3 L353P gain of function mutation. We show RM1mAb and repurposed inhibitor TH5487 synergistically inhibit inflammasome activation. These findings illustrate the promise of exploiting FCγRs as a means of IgG entry to target cytosolic proteins and improve human health. One-Sentence Summary: RM1mAb and TH5487 synergistically inhibit inflammasome activation in human FCAS PBMCs.