The effectiveness of current treatment for age related macular degeneration (AMD) by targeting one molecule is limited due to its multifactorial nature and heterogeneous pathologies. Treatment strategy to target multiple signaling pathways or pathological components in AMD pathogenesis is under investigation for better clinical outcome. Inhibition of the redox function of apurinic endonuclease 1/redox factor-1 (APE1) was found to suppress endothelial angiogenesis and promote neuronal cell recovery, thereby may serve as a potential treatment for AMD. In the current study, we for the first time have found that a specific inhibitor of APE1 redox function by a small molecule compound E3330 regulates retinal pigment epithelium (RPEs) cell response to oxidative stress. E3330 significantly blocked sub-lethal doses of oxidized low density lipoprotein (oxLDL) induced proliferation decline and senescence advancement of RPEs. At the same time, E3330 remarkably decreased the accumulation of intracellular reactive oxygen species (ROS) and down-regulated the productions of monocyte chemoattractant protein-1 (MCP-1) and vascular endothelial growth factor (VEGF), as well as attenuated the level of nuclear factor-κB (NF-κB) p65 in RPEs. A panel of stress and toxicity responsive transcription factors that were significantly upregulated by oxLDL was restored by E3330, including Nrf2/Nrf1, p53, NF-κB, HIF1, CBF/NF-Y/YY1, and MTF-1. Further, a single intravitreal injection of E3330 effectively reduced the progression of laser-induced choroidal neovascularization (CNV) in mouse eyes. These data revealed that E3330 effectively rescued RPEs from oxidative stress induced senescence and dysfunctions in multiple aspects in vitro, and attenuated laser-induced damages to RPE-Bruch׳s membrane complex in vivo. Together with its previously established anti-angiogenic and neuroprotection benefits, E3330 is implicated for potential use for AMD treatment.
Keywords: AMD, age related macular degeneration; AP-1, activator protein 1; APE1, apurinic endonuclease 1/redox factor-1; APE1/Ref-1redox function; Age-related macular degeneration.; AhR, aryl hydrocarbon receptor; ApoE, apolipoprotein E; CBF/NF-Y/YY1, CCAAT binding factor/nuclear factor-Y/Yin Yang 1; CECs, choroidal endothelial cells; CNV, choroidal neovascularization; DCFH-DA, dichlorodihydrofluorescin diacetate; DMSO, dimethylsulphoxide; E3330; Fluc, firefly luciferase; HIF-1α, hypoxia inducible factor-1α; HSF1, heat-shock factor 1; IκB-α, inhibitory NF-κB-α; MCP-1, monocyte chemoattractant protein-1; MTF1, metal regulatory transcription factor 1; NF-κB, nuclear factor-κB; Nox, NADPH oxidase; Nrf, nuclear factor erythroid-2-related factor; Oxidative stress; RNV, retinal neovascularization; ROS, reactive oxygen species; RPE, retinal pigment epithelium; RVECs, retinal vascular endothelial cells; Retinal pigment epithelial cell; Rluc, renilla luciferase; SA-β-gal, senescence associated β-gal; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; TUNEL, TdT mediated dUTP-fluorescein nick end-labeling; Transcription factor; VEGF, vascular endothelial growth factor; oxLDL, oxidized low density lipoprotein; redox, reduction/oxidation.