STING up-regulates VEGF expression in oxidative stress-induced senescence of retinal pigment epithelium via NF-κB/HIF-1α pathway

Aging-related dysfunction of retinal pigment epithelium (RPE) is the main pathogenic factors for pathological angiogenesis due to dysregulated vascular endothelial growth factor (VEGF) in retinal vascular diseases such as age-related macular degeneration (AMD) and diabetic retinopathy (DR). However, the molecular mechanism behind the up-regulation of VEGF in senescent RPE is still blurred.As oxidative damage is the key cause of RPE dysfunction, we employed a model of oxidative stress-induced premature senescence of ARPE-19 to explore the effect of senescent RPE on VEGF.We reported that senescent ARPE-19 up-regulated VEGF expression under both short-term and prolonged H2O2 treatment, accompanying with increased HIF-1α, the key mediator of VEGF. STING signaling, which could be activated by oxidative stress-damaged DNA, was also observed to be increased in senescent ARPE-19 treated with H2O2. And the inhibition of STING significantly reduced HIF-1α expression to alleviate the up-regulation of VEGF. NF-κB was also shown to be involved in the regulation of VEGF in senescent ARPE-19 in response to STING signaling. Furthermore, oxidative stress impaired the lysosomal clearance of damaged DNA to enhance STING signaling, thereby up-regulating VEGF expression in senescent RPE.Our data provide evidence that STING plays an important role in VEGF regulation in senescent RPE induced by oxidative stress.