ABCC4 impairs the clearance of plasma LDL cholesterol through suppressing LDLR expression in the liver

Abstract

Low expression level of low-density lipoprotein receptor (LDLR) in hepatocytes leads to hypercholesterolemia and eventually contributes to atherosclerotic cardiovascular disease (ASCVD). Here, we report that inhibition of hepatocyte ABCC4, identified as a top hit from large-scale CRISPR/Cas9 screens, significantly increases hepatic LDLR abundance and enhances LDL cholesterol clearance. As a hepatic transporter for cAMP efflux, ABCC4 silencing alters its intracellular distribution and activates the downstream Epac2/Rap1a signaling pathway, which ultimately blocks PCSK9 protein expression, thereby preventing lysosomal degradation of LDLR. Furthermore, in both male mice and cell models, we demonstrate that liver-specific disruption and pharmacological inhibition of ABCC4 elevate hepatic plasma membrane LDLR levels and reduce plasma LDL cholesterol through ABCC4-cAMP-PCSK9 pathway. Collectively, our genome-wide CRISPR screening offers a valuable resource for identifying LDLR modifiers, providing potential insights for therapeutic strategies in hypercholesterolemia and atherosclerosis.