Curcuma longa-derived extracellular vesicle-like particles ameliorate retinal neovascularization through HIF-1α and NRF2 signaling

OBJECTIVE: Retinal neovascularization is a leading cause of irreversible blindness worldwide. Chinese herbal medicines have unique therapeutic properties, such as antioxidant, anti-inflammatory, and neuroprotective effects. This study aims to investigate the therapeutic effects and underlying mechanisms of the Chinese medicinal herb Curcuma longa-derived extracellular vesicle-like particles (CL-EVLPs) in a mouse model of retinal neovascularization. METHODS: CL-EVLPs were extracted from fresh Curcuma longa rhizomes through differential centrifugation and sucrose density gradient centrifugation and characterized by transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA), and western blot analysis of EVLP-associated protein markers. CL-EVLPs were administered to oxygen-induced retinopathy (OIR) model mice via intravitreal injection. The therapeutic effects were evaluated using retinal flat mounts, fundus fluorescein angiography (FFA), and reactive oxygen species (ROS) staining. The underlying molecular mechanisms were explored through metabolomics, transcriptomics, and network pharmacology analyses, and the expression levels of relevant factors were quantified using real-time polymerase chain reaction (PCR) or western blotting. In vitro experiments were conducted using human retinal microvascular endothelial cells (hRMECs) and BV2 microglia. RESULTS: CL-EVLPs exhibited typical EV-like characteristics, including a saucer‑ or cup‑shaped morphology, a mean diameter of 140.7 nm, and enrichment of the EV‑related protein ARF1. CL-EVLPs effectively inhibited neovascularization in the OIR model, as evidenced by reduced pathological neovascular tufts and avascular zones and decreased vascular permeability and tortuosity. Furthermore, CL-EVLPs significantly decreased ROS production in the retinas of OIR mice. Mechanistically, CL-EVLPs inhibited HIF-1α/VEGF/ERK signaling and activated the NRF2/HO-1 antioxidant pathway. In vitro experiments confirmed that CL-EVLPs inhibited endothelial cell viability and alleviated oxidative stress in microglia. Integrated network pharmacology and metabolomics analyses proved that the cargo molecules of CL-EVLPs, such as curcumin and its derivatives, auraptene, and triptophenolide, exhibit regulatory antioxidant and anti-inflammatory effects and modulate multiple signaling pathways associated with retinal neovascular diseases. CONCLUSION: CL-EVLPs effectively suppress retinal neovascularization by inhibiting the HIF-1α/VEGFA/ERK axis and activating the NRF2/HO-1 pathway. This study suggests that CL-EVLPs, as a multitarget therapeutic strategy, hold promising clinical translational potential for the treatment of retinal neovascular diseases.