Amygdalin alleviates MAFLD via inhibiting cytoplasmic calcium ion overload-induced liver sinusoidal endothelial cell defenestration.

Abstract

BACKGROUND: Semen Persicae, a traditional Chinese medicine, has shown potential in alleviating metabolic dysfunction-associated fatty liver disease (MAFLD). However, the complexity of components limits its clinical application. PURPOSE: To identify the key active component of Semen Persicae responsible for attenuating MAFLD and to elucidate the underlying mechanism. METHODS: The chemical components of Semen Persicae were characterized using mass spectrometry. A high-fat diet-induced MAFLD mouse model and primary liver sinusoidal endothelial cells (LSECs) were employed. Liver histopathology was used to evaluate the efficacy and safety of amygdalin (Amy). Single-cell RNA sequencing (scRNA-seq) and untargeted metabolomics analyses of mouse livers were integrated to preliminarily investigate the mechanism. Scanning electron microscopy (SEM) and assessment of fenestration markers were used to evaluate the fenestrae status of LSECs. Cytoplasmic calcium ion (Ca2+) staining, along with measurements of prostaglandin E2 (PGE2) and inositol triphosphate (IP3) levels, was applied to assess Ca2+ overload in LSECs. RESULTS: Mass spectrometry identified Amy as a major component of Semen Persicae. In a diet-induced MAFLD mouse model, Amy treatment dose-dependently attenuated disease progression, showing therapeutic efficacy comparable to liraglutide, with marked improvements in systemic metabolic parameters and significant reductions in hepatic steatosis and inflammation. Single-cell RNA sequencing identified liver sinusoidal endothelial cells (LSECs) as the most responsive cell population, with Amy markedly reducing the abundance of capillarized LSEC states. Ultrastructural analyses further demonstrated that the reduced fenestration density observed in MAFLD was substantially restored following Amy treatment. Integrated transcriptomic and metabolomic analyses revealed that arachidonic acid metabolism and endoplasmic reticulum Ca²⁺ signaling were prominently affected by Amy. In vitro experiments further confirmed that Amy reduced elevated PGE2 and IP3 levels, thereby suppressing excessive endoplasmic reticulum Ca²⁺ release. CONCLUSION: Amy effectively ameliorates LSECs defenestration by reversing IP3-induced cytoplasmic Ca2+ overload, highlighting its potential as a plant-derived therapeutic candidate for MAFLD.