Abstract
Purpose :
The NLRP3 inflammasome is activated in the retinal pigment epithelium (RPE) in atrophic age-related macular degeneration (AMD) and may contribute to pathogenesis and progression of this currently untreatable disease. NLRP3 inhibition provides a potential therapeutic strategy in atrophic AMD. We tested small molecule-based selective NLRP3 inhibitors (IFM-514, IFM-632, CRID3) for their efficacy in human and murine RPE cells.
Methods :
Inflammasome activation was induced in primary human RPE cells, ARPE-19 cells, and murine RPE organ cultures by various different stimuli. For this, cells were primed with IL-1α and subsequently subjected to either lysosomal membrane permeabilization (LMP) by leucyl-leucine methyl ester (Leu-Leu-OMe), oxidative damage induced by hydrogen peroxide, lipofuscin-mediated photooxidative damage induced by incubation with 4-hydroxynonenal-modified photoreceptor outer segments and subsequent blue light irradiation, or P2X7R activation by benzoylbenzoyl-ATP. RPE/choroid/sclera eye cups from Abca4-/-, Abca4-/-/Nlrp3-/-, and wildtype mice were exposed to blue light irradiation or Leu-Leu-OMe. Inflammasome activation was assessed by means of IL-1β release, lactate dehydrogenase release, and ZO-1 staining.
Results :
Each of the described stimuli induced pronounced inflammasome activation in human RPE cells. IFM-632, IFM-514, and CRID3 significantly suppressed inflammasome activation in these models. IFM-632 at 0.01 µM reduced IL-1β release induced by LMP, oxidative damage, photooxidative damage, and P2X7R activation in ARPE-19 cells to 16.6% (p=0.005), 6.9% (p=0.003), 39.4% (p=0.010), and 12.7% (p<0.001), respectively. Likewise, inflammasome activation in blue light-irradiated Abca4-/- murine RPE and in Leu-Leu-OMe-treated wildtype murine RPE was significantly reduced by treatment with the NLRP3 inhibitors.
Conclusions :
Selective NLRP3 inhibitors are effective in human and murine RPE cells, making them promising agents for the future evaluation of inflammasome inhibition as a potential new therapeutic strategy in atrophic AMD.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.