Abstract
Purpose :
Activation of innate immunity by uncompensated stress is associated with retinal pigment epithelial (RPE) cell damage and age-related macular degeneration. The inflammasomes are activated by specific triggers, also known as sensors: NLRP3 and NOD2. Dysregulation of external factors leads to an inflammatory cascade that results in the activation of the inflammasomes. We hypothesized that the docosahexaenoic acid-derived lipid mediators, NPD1 and ELVs, downregulate inflammasome-induced response.
Methods :
Inflammasome activation was induced in human RPE cells using oxidized LDL (120-150 µg/ml) or IL-1A+ H2O2 (1200 µM for 6-8h). Cells were pre-treated with ELVs (300 nM) or NPD1 (200 nM) 30 min prior to cell stress. Expression of inflammasome-related proteins and genes was determined by Western Blot and qPCR analysis. We used immunocytochemistry to determine the morphology of cells and the assembly of the inflammasome.
Results :
NLRP3 expression was increased by oxidized LDL and NOD2 was increased by both oxidized LDL and IL-1A+ H2O2. They both induced the assembly of the inflammasome. NPD1 decreased NLRP3 expression while all lipid mediators prevented the augmentation of NOD2 by the stressors. The bioactive lipids decreased the expression of downstream cytokines: IL-1β, IL-6, and IL-8 which were enhanced by the cellular stressors.
Conclusions :
NPD1 and ELVS downregulated the expression of the inflammasome sensors with subsequent downregulation of the inflammasome. This finding suggests that the lipid mediators powerfully downregulate the pro-inflammatory response and promote survival by preventing the initiation of the inflammasome assembly.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.