Abstract
Purpose :
Multiple lines of evidence implicate the NLRP3 inflammasome in retinal pigment epithelium (RPE) degeneration. First, relevant stimuli including oxidative or lysosomal stress activate NLRP3. The pathway is additionally activated in the diseased retina. Furthermore, genetic and pharmacological inhibition reduces both inflammation and cytotoxicity in preclinical models. Here, we report the discovery and assessment of biological activity of novel small molecule NLRP3 pathway inhibitors that protect the RPE during pathological conditions.
Methods :
Assay conditions were established to induce canonical NLRP3 dependent IL1b and caspase-1 activity in both THP-1 and U937 cells. A GFP-ASC fusion expressing line was used to assess compound effects on multimeric ASC protein complexes using quantitative image analysis. Undesirable NLRP3 independent effects on inflammation and toxicity were assessed by macrophage TNFa production and RPE cell viability, respectively.
Results :
Candidate NLRP3 inhibitors reduced IL-1b secretion in multiple human macrophage lines. On-target molecules additionally reduced caspase-1 activity as well as the formation of the multimeric inflammasome complex. These compounds did not show effects on NLRP3 independent inflammation or RPE cell toxicity. Furthermore, candidates were tested for protection of the RPE against oxidative and lysosomal stress.
Conclusions :
Novel potent NLRP3 inhibitors were identified that act on all levels of the NLRP3 pathway without non-specific anti-inflammatory action or toxicity. These small molecules have potential as novel therapies for retinal and other diseases.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.