NLRP3 Inflammasome Activation in Endothelial Cells and the Potential Modulatory Role of Riociguat in the Nitric Oxide Pathway

Background:The NOD-like receptor protein 3 (NLRP3) inflammasome is a cytoplasmic protein complex activated by damageassociated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs), resulting in the release of proinflammatory cytokines such as IL-1 and IL-18.In this pathway, the activation of NF-B plays a key role.Many studies have demonstrated the significant role of IL-1 in activating NF-B.The aim of this study: We hypothesized that the activation of the nitric oxide (NO)-(sGC)-(cGMP)-PKG through the vasodilator-stimulated phosphoprotein (VASP) pathway may lead to antiinflammatory effects through (NFB)-NLRP3 inhibition on endothelial cells.Methods and Results: This experimental research was conducted using human pulmonary artery endothelial cells (HPAEC).The growth and monitoring of cell cultures were done according to strict guidelines and protocols.In our study, we added TNF (10 mg/mL) to activate the inflammasome.Ten minutes later, riociguat (RCG) was added at six different concentrations (50 M, 10 M, 5 M, 1 M, 0.5 M, and 0.1 M) to activate the NO pathway, followed by 15 mM of ATP.Incubation is continued at different times (60, 90, and 120 minutes).The measurement of caspase-1 activity was performed using a luminescence assay.Our results have once again demonstrated the successful activation of the inflammasome by TNF.We suggest that the highest concentration of RCG, 50 M, in our study was insufficient to trigger the NO pathway; additionally, more complex molecular pathways may be involved, and further investigations are warranted to clarify the underlying complex mechanism.(International