Kavain alleviates choroidal neovascularization via decreasing the activity of the HIF-1α/VEGF-A/VEGFR2 signaling pathway and inhibiting inflammation

Purpose: Neovascular age-related macular degeneration (nAMD) is a prevalent cause of blindness in the elderly. Standard treatment includes anti-vascular endothelial growth factor (VEGF) drugs, including Bevacizumab, Ranibizumab, and Aflibercept. However, anti-VEGF drugs may have limited efficacy and cause drug resistance. Recently, inflammation has been identified as one of the main risk factors in the progression of AMD. This study explores whether Kavain, an anti-inflammatory molecule from Piper methysticum, can treat choroidal neovascularization (CNV). Materials and methods: Various experiments were conducted to assess the Kavain’s toxicity. The impact of Kavain on in vitro cultured endothelial cells was examined through 5-Ethynyl-20-deoxyuridine (EdU) assays, transwell migration assays, and tube formation assays. The therapeutic effects of Kavain on CNV were investigated using a Laser-induced CNV mice model. Laser burns, approximately two papillary diameters away from the mouse optic nerve, were uniformly induced (532 nm wavelength, 0.1 s duration, 120 mW power, and 50 µm spot size). To elucidate the mechanism of Kavain, network pharmacology analysis, molecular docking, and western blots were performed. Results: Kavain exhibited no apparent toxicity both in vitro and in vivo. Kavain significantly decreased endothelial cell viability, proliferation, migration, and tube formation ability in a dose-dependent manner compared to the hypoxia groups (P<0.05). Kavain alleviated CNV in the laser-induced CNV mouse model compared to the control groups (P<0.05). These effects were statistically significantly enhanced in the Kavain plus Aflibercept groups (P<0.05). Following Kavain administration, the expression levels of various inflammatory factors were markedly reduced in retinal pigment epithelium (RPE) /choroid complexes (P<0.05). Mechanistically, we proved that Kavain decreased the activity of the hypoxia-inducible factor 1 α (HIF-1 α)/VEGF-A/VEGF receptor 2 (VEGFR2) signaling pathway. Conclusions: Our study is the first to demonstrate Kavain's potential as a promising treatment for nAMD, owing to its dual effects of anti-inflammation and anti-angiogenesis.