Abstract 4137713: Epsin-Mediated PCSK9-LDLR Interaction: A New Therapeutic Target for Atherosclerosis

Introduction: Atherosclerosis, a leading cause of cardiovascular diseases, causes about 17.9 million deaths annually. It is driven by high levels of LDL cholesterol (LDL-C). The liver's LDL receptor (LDLR) removes LDL-C from the bloodstream, but its degradation by PCSK9 exacerbates the condition. Epsin, an endocytic adaptor protein crucial for clathrin-mediated endocytosis, plays a significant role in atherosclerosis, particularly lipid metabolism. Hypothesis: We propose that hepatic epsins significantly contribute to atherosclerosis by facilitating the PCSK9-induced degradation of LDLR, thus impeding LDL-C clearance. Objectives: This study aims to investigate hepatic epsins' role in PCSK9-mediated LDLR degradation and its effects on LDL-C levels and atherosclerosis development. Using bioinformatics, we will analyze enriched pathways and networks to study epsins modulation, which will be validated through biochemical assays and in vivo experiments. Methods: Liver-specific double knockout (DKO) mice lacking epsin1 and epsin2 were created on an ApoE -/- background. Atherosclerosis was induced using a Western diet (WD), and blood cholesterol and triglyceride levels were monitored. We employed high-resolution single-cell RNA sequencing (scRNA-seq) to analyze cellular transitions, intercellular interactions, and Gene Ontology pathway enrichment within hepatocyte-derived data. Results: RNA velocity reveals the transition from lipogenic Alb hi Hepatocytes to glucogenic Hnf4a hi Hepatocytes in Liver-DKO mice on an ApoE -/- background on a WD. Liver-DKO mice on an ApoE -/- background on a WD exhibited significantly reduced atherogenesis and lower blood cholesterol and triglyceride levels compared with wild-type on an ApoE -/- background on a WD. Gene Ontology enrichment analysis showed elevated pathways for LDL particle clearance and enhanced LDLR-cholesterol communication scores in Liver-DKO mice, suggesting improved LDL-C clearance. Nanoparticle-encapsulated siRNAs targeting liver epsins effectively inhibited atherosclerosis. Conclusion: Epsin depletion in the liver upregulated LDLR protein levels, and PCSK9-triggered LDLR degradation was abolished, preventing atheroma progression. Targeting liver epsins presents a novel therapeutic strategy for atherosclerosis, supported by network analysis and predictive modeling for effective interventions.