Down-regulation of ATP8B2 in Foam Cells Inhibits Autophagic Flux and ox-LDL Degradation in Atherosclerosis.

Abstract

Our study aims to screen and explore the potential molecular mechanisms of atherosclerosis using a comprehensive research approach combining bioinformatics analysis and molecular biology experiments. Bioinformatics analyses were conducted to screen for key genes with significantly differential expression in atherosclerosis. Subsequently, macrophages and foam cells induced from THP-1 cells were utilized to validate the function of these key genes through siRNA knockdown. Molecular biology experiments encompassed reverse transcription polymerase chain reaction (RT-PCR), Western Blotting, immunofluorescence staining, and JC-1 probe detection of mitochondrial membrane potential. ATP8B2, encoding a P4-ATPase, was significantly downregulated in both plaque tissues and circulating macrophages of atherosclerosis patients. This enzyme influences membrane fusion and other dynamic processes by affecting the asymmetric distribution of phospholipids within the bilayer. Knockdown of ATP8B2 expression significantly inhibited autophagic flux in macrophages, manifested by abnormal accumulation of LC3-II and p62 protein levels. Furthermore, downregulation of ATP8B2 expression significantly inhibited the degradation of oxidized low-density lipoprotein (ox-LDL) by macrophages. Simultaneously, reduced ATP8B2 expression led to decreased mitochondrial membrane potential and mitochondrial dysfunction. Our study unveils for the first time the crucial role of ATP8B2 in atherosclerosis, particularly in maintaining autophagic flux, promoting ox-LDL degradation, and sustaining mitochondrial homeostasis.