Optimizing PDIA1 Inhibition as a Strategy to Inhibit NLRP3 Inflammasome Activation and Activity

Abstract

The NLRP3 inflammasome is a protein complex that promotes pro-inflammatory signaling as part of the innate immune response. Hyperactivation of the NLRP3 inflammasome has been implicated in many inflammatory and neurodegenerative diseases, leading to significant effort in developing strategies to limit its activation to intervene in these disorders. We previously showed that pharmacologic inhibition of the endoplasmic reticulum (ER)-localized protein disulfide isomerase PDIA1 suppresses NLRP3 activation and activity, identifying PDIA1 as a potential therapeutic target to mitigate hyperactive NLRP3 activity. Herein, we screen PDIA1 inhibitors to identify highly-potent compounds, including P1 and PACMA31, that pharmacologically target PDIA1 and block NLRP3 inflammasome assembly and activity. While sustained treatment with these PDIA1 inhibitors reduces THP1 viability, we show that acute treatment with these compounds is sufficient to both fully modify PDIA1 and inhibit NLRP3 inflammasome activity independent of any overt cellular toxicity. These results establish a treatment paradigm that can be exploited to develop highly-selective PDIA1 inhibitors to mitigate hyperactive NLRP3 inflammasome activity implicated in etiologically-diverse diseases.