Abstract
Purpose :
Apurinic/apyrimidinic endonuclease 1/reduction-oxidation factor 1 (APE1/Ref-1) is both a DNA repair enzyme and a redox (reduction-oxidation) signaling protein. We have identified Ref-1 as a potential therapeutic target for neovascular age-related macular degeneration (nvAMD) and other neovascular eye diseases; Ref-1 inhibitor APX3330 is currently in Phase II trials for diabetic retinopathy. Ref-1’s redox-sensitive transcription activation modulates angiogenesis and inflammation as it stimulates transcription factors including HIF1-α, NF-κB, and STAT3. We previously showed that inhibiting Ref-1’s redox function reduces angiogenesis in vitro and in murine laser-induced choroidal neovascularization (L-CNV). This study aimed to analyze Ref-1 expression during the progression of L-CNV in mice and in human nvAMD and control eyes.
Methods :
L-CNV was induced in 7-week old, wild-type female C57BL/6J mouse eyes to simulate features of nvAMD, and eyes harvested at 1, 3, 5, 7, 10, and 14 days after laser treatment. De-identified paraffin sections of human nvAMD and age-matched control patients were acquired from the National Disease Research Interchange (NDRI). Ref-1 expression was analyzed by confocal microscopy on immunostained retinal and choroidal flat-mounts and frozen cryosections from mouse eyes, and on human nvAMD vs control sections.
Results :
In L-CNV, Ref-1 was highly expressed in and around the lesions, especially soon after the laser treatment on days 1, 3, and 5. The higher expression of Ref-1 was seen in the ganglion cell layer, inner and outer nuclear layers, inner and outer segments of photoreceptors in the retina and in the retinal pigment epithelium (RPE)/choroid. Expression was lower in lesions at later time points on days 7, 10, and 14. The human eye immunostaining showed that Ref-1 is predominantly highly expressed in the RPE layer in nvAMD compared to healthy eyes.
Conclusions :
High expression of Ref-1 in L-CNV mice eyes at different time points and in the eyes of human nvAMD patients further supports a functional role of Ref-1 in CNV. Overall, this study provides further insight into the importance of Ref-1 for nvAMD pathogenesis and highlights the potential of this novel drug target for nvAMD.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.