Efficacy of novel selective NLRP3 inhibitors in human and murine retinal pigment epithelial cells
NLRP3 inflammasome activation in the retinal pigment epithelium (RPE) is observed in atrophic age-related macular degeneration (AMD), and pharmacological NLRP3 inhibition may provide a therapeutic strategy to halt disease progression. We tested selective NLRP3 inhibitors (IFM-514, IFM-632, and CRID3) for their efficacy in human and murine RPE cells. Inflammasome activation was induced in primary human RPE cells and ARPE-19 cells following priming with IL-1α by different stimuli, including lysosomal membrane permeabilization 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, and P2X7 receptor activation by benzoylbenzoyl-ATP. Independent of the applied activation mechanism, treatment with the NLRP3 inhibitors IFM-632, IFM-514, and CRID3 resulted in a significant suppression of inflammasome activation as assessed by IL-1β and LDH release. Likewise, inflammasome activation in blue light-irradiated Abca4−/− mouse and Leu-Leu-OMe-treated wild-type mouse RPE/choroid/sclera eye cups was significantly reduced by treatment with the NLRP3 inhibitors. These results indicate that the investigated selective NLRP3 inhibitors are effective in human and murine RPE cells, thus representing promising agents for the future evaluation of inflammasome inhibition as a therapeutic strategy in atrophic AMD.
• NLRP3 inhibitors suppress inflammasome activation in human RPE cells independent of trigger.
• Light-induced inflammasome activation in Abca4−/− mouse eye cups is reduced by NLRP3 inhibitors.
• Novel selective NLRP3 inhibitors are effective in human and murine RPE cells.
• Promising compounds for pharmaceutical intervention in atrophic AMD.
KeywordsAge-related macular degeneration Interleukin-1 Lysosomal membrane permeabilization Oxidative damage P2X7 receptor
NLRP3 inhibitors IFM-632 and IFM-514 were kindly provided by IFM Therapeutics (Boston, Massachusetts, USA). Abca4−/− mice were a kind gift from Alun Barnard (University of Oxford, Oxford, UK).
This work was supported by the China Scholarship Council (CSC; to L.W.), Ernst and Berta Grimmke Foundation (to P.P.L. and T.U.K.), German Research Foundation (DFG; grant KR 2863/7-2 to T.U.K., collaborative research centers SFB/TRR57 and SFB/TRR83), Volker Homann Foundation (to T.U.K.), Dr. Eberhard und Hilde Rüdiger Foundation (to T.U.K.), and the European Research Council (ERC) grant InflammAct (to E.L.).
Compliance with ethical standards
Conflict of interest
L. Wang, S. Schmidt, P. P. Larsen declare that they have no conflict of interest. J. H. Meyer declares support from Heidelberg Engineering. W. R. Roush is a shareholder and employee of IFM Therapeutics. E. Latz is a co-founder and consultant of IFM Therapeutics. F. G. Holz declares support from Acucela, Allergan, Bayer, Centervue, NightstarX, Novartis, Genentech/Roche, Heidelberg Engineering, Optos, and Carl Zeiss Meditec. T. U. Krohne declares support from Alimera Sciences, Bayer, Heidelberg Engineering, and Novartis.
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