Chrysin Alleviates DNA Damage to Improve Disturbed Immuno-Homeostasis and Pro-Angiogenic Environment in Laser-Induced Choroidal Neovascularization

Abstract Background: Choroidal neovascularization (CNV) is a devastating pathology of numerous ocular diseases, such as wet age-related macular degeneration (wAMD), which causes irreversible vision loss. Although anti-VEGF therapy has been widely used, poor response or no response exits in some patients, suggesting that some other important angiogenic components play roles. Therefore, the underlined mechanism need to be clarified and new target of anti-angiogenic therapy is urgently needed. Damaged retinal pigment epithelium (RPE) cells have been demonstrated to activate inflammasome, drive a degenerative tissue environment and an enhanced pro-angiogenic response, which emphasizes the dysfunction of RPE, may be the hallmark of the pathogenesis.Methods: C57BL/6J male mice aged between 6 and 8 weeks were subjected to laser-induced CNV models. Chrysin was administered intragastrically at 25 mg/kg daily for 3 days or one week after laser-treated. Then to observe the CNV areas and CNV thickness, immunofluorescence staining of choroidal flatmount, SD-OCT and fluorescein angiograghy were performed, respectively. To further confirm the effect of chrysin on stress-induced DNA damage in RPE cells, RPE cells were administered with A2E and western-blot, cell viability assay, immunofluorescence chromosome PNA-FISH and SA-β-gal staining were performed. To elucidate the underlying mechanism, we performed RNA-seq and bioinformatics analyses.Results: In this study, we demonstrated that chrysin could successfully alleviated choroidal neovascularization. We show that DNA damage of RPE cells is remarkable in laser-induced choroidal neovascularization, resulting in inflammation response, which can be ameliorated by chrysin through inactivation of STAT3. Also, we identify that chrysin can reduce DNA damage, especially telomere erosion, simultaneously compromise the dysfunction of RPE and the secretion of SASP factor in vitro. Mechanistically, KEGG pathway analyzes show that chrsyin improves inflammatory imbalance mainly through down-regulation of IL17 pathway in the laser- induced CNV development.Conclusions: Our results indicate the interplay between DNA damage, perturbed RPE homeostasis, inflammatory imbalance and angiogenesis in laser-induced choroidal neovascularization. Importantly, chrysin may be an effective therapeutic supplement for CNV.