Tilapia skin-derived oligopeptide TBP-1 intervenes in age-related macular degeneration in vitro via ROS-dependent regulation of the HIF-1α/VEGF axis and structural analysis

Age related macular degeneration (AMD) is one of the main causes of blindness in. elderly patients, and its treatment methods include intraocular injection and oral. administration, requiring long-term treatment and suboptimal efficacy. Tilapia skin-derived oligopeptides, characterized by high safety and bioactivity, emerge as a promising source of functional food ingredients. Here, we investigated the protective mechanism of TBP-1 (Ser-Val-Val-Ala-Ile), a pentapeptide isolated from tilapia skin, against hypoxia-induced damage in retinal pigment epithelial (ARPE-19) cells and angiogenesis in human umbilical vein endothelial cells (HUVECs). In the functional evaluation, TBP-1 notably attenuated ROS overproduction in CoCl 2 -induced ARPE-19 cells, simultaneously suppressing the stabilization of hypoxia-inducible factor-1α (HIF-1α), which was associated with reduced vascular endothelial growth factor (VEGF) transcription, diminished inflammatory factor levels, and restoration of normal autophagic flux. To validate the ROS-dependent nature of this regulatory pathway, we performed a rescue experiment using N-acetylcysteine (NAC), a well-characterized ROS scavenger. In HUVECs activated by VEGF, TBP-1 decreased the phosphorylation of VEGFR-2 and dampened the activation of the MAPK signaling pathway, resulting in dose-dependent inhibition of cell migration, invasion, and the formation of capillary-like tubular structures. Molecular docking and quantum chemical analyses suggested that the bioactivity of TBP-1 may rely on the electron-donating property of the Ser residue and hydrophobic interactions mediated by Ile, both of which are critical for its ROS scavenging ability and predicted interaction with HIF-1α. Collectively, these findings suggest that TBP-1 is a multi-target functional food supplement for preventing AMD by targeting the ROS/HIF-1α/VEGF axis, providing a theoretical basis for the high-value utilization of tilapia skin.