Abstract
Nonfibrillar amyloid-β oligomers (AβOs) are a major component of drusen, the sub-retinal pigmented epithelium (RPE) extracellular deposits characteristic of age-related macular degeneration (AMD), a common cause of global blindness. We report that AβOs induce RPE degeneration, a clinical hallmark of geographic atrophy (GA), a vision-threatening late stage of AMD that is currently untreatable. We demonstrate that AβOs induce activation of the NLRP3 inflammasome in the mouse RPE in vivo and that RPE expression of the purinergic ATP receptor P2RX7, an upstream mediator of NLRP3 inflammasome activation, is required for AβO-induced RPE degeneration. Two classes of small molecule inflammasome inhibitors—nucleoside reverse transcriptase inhibitors (NRTIs) and their antiretrovirally inert modified analog Kamuvudines—both inhibit AβOs-induced RPE degeneration. These findings crystallize the importance of P2RX7 and NLRP3 in a disease-relevant model of AMD and identify inflammasome inhibitors as potential treatments for GA.
Highlights
Geographic atrophy (GA), an irreversible and untreatable form of dry age-related macular degeneration (AMD), causes blindness in millions of individuals worldwide.[1]
Amyloid-β oligomers (AβOs) induce NLR family pyrin domain containing 3 (NLRP3) inflammasome assembly in the retinal pigmented epithelium (RPE) We monitored NLRP3 inflammasome priming in the RPE in vivo following subretinal injection of AβOs by using Nlrp3-GFP mice, a reporter mouse line in which transcription of the fluorescent reporter is controlled by endogenous Nlrp[3] regulatory elements.[31]
We found that the NLRP3 inflammasome consistently takes a central position in aging as it is activated by a vast variety of aging-associated danger patterns.[44,45] subretinal injection of AβOs induced RPE degeneration in P2rx7hP2RX7Flox/Best1-Cre+ mice, which expressed human P2X7R but did not induce RPE degeneration in P2rx7hP2RX7/Best1-Cre+
Summary
Geographic atrophy (GA), an irreversible and untreatable form of dry age-related macular degeneration (AMD), causes blindness in millions of individuals worldwide.[1]. We tested if P2RX7 expression is necessary for AβOs-induced RPE degeneration.
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