N-acetylcysteine amide alleviates pathological neovascularization through mitochondrial protection and energy metabolism reprogramming of vascular endothelial cells

Hypoxia-induced pathological neovascularization is a major contributing factor to a variety of diseases across different age groups. Currently, the predominant therapeutic approach involves the repeated injection of anti-vascular endothelial growth factor (VEGF) agents, which are associated with several adverse effects that limit their long-term application. This study concentrates on the upstream regulators of VEGF within vascular endothelial cells (VECs) and uses the oxygen-induced retinopathy mouse model to demonstrate that N-acetylcysteine amide (NACA) exhibits significant antiangiogenic properties both in vitro and in vivo. Notably, NACA preserves mitochondrial homeostasis and mitigates mitochondrial reactive oxygen species (mtROS) in VECs. Moreover, smart RNA sequencing and the Oxygen Consumption Rate experiment indicate that NACA reprograms the cellular energy metabolism by restoring oxidative phosphorylation (OXPHOS) via targeting mitochondrial complexes I/V, a mechanism further confirmed by the partial blockade of NACA's effect with oligomycin. Additionally, NACA effectively rescues inner-retinal neurons within the avascular areas. We observed minimal toxicity after intravitreal administration of NACA, suggesting a favorable safety profile for its therapeutic use. Collectively, our findings confirmed that targeting mitochondrial homeostasis and cellular energy metabolism in VECs could serve as a promising therapeutic strategy, with NACA anticipated to emerge as a novel drug for diseases characterized by pathological neovascularization.