A novel mTORC1-NPC2 axis suppresses lipophagy and drives atherosclerotic plaque progression.

BACKGROUND: Endothelial dysfunction is a critical initiating factor in atherosclerosis (AS), with NPC2 and mTORC1 playing key roles in the regulation of endothelial lipophagy. OBJECTIVE: To reveal that hypercholesterolemia disrupts endothelial lipophagy via the mTORC1-NPC2 axis and to explore its role in atherosclerotic progression. METHODS: Thirty AS patients and 30 healthy controls were enrolled. Lipophagy markers in endothelial cells isolated from plaque and non-plaque regions were assessed. Exosomes were characterized and their effects on endothelial viability were evaluated. Multi-omics analyses identified key differentially expressed pathways, which were validated in a high-cholesterol diet mouse model and in human aortic endothelial cells (HAoECs) using pharmacological activation, knockout, and molecular interaction assays. RESULTS: AS patients showed significantly elevated serum cholesterol and suppressed lipophagy in plaque-derived endothelial cells. Plaque-derived exosomes inhibited endothelial cell viability and promoted injury marker expression. mTOR signaling was identified as a candidate activated pathway in plaque endothelium, and pharmacological activation of mTOR in HAoECs was associated with impaired lipophagy. Rapamycin attenuated HCD-induced mTOR activation and lipid accumulation in mice. GST pull-down and molecular docking supported a potential association between mTOR and NPC2, while NPC2 deficiency attenuated the rapamycin-associated restoration of lipophagy and lipid homeostasis. CONCLUSION: Hypercholesterolemia disrupts endothelial lipophagy through the mTORC1-NPC2 signaling axis, promoting lipid accumulation and accelerating atherosclerosis. Targeting this pathway may offer a novel therapeutic strategy for AS.