SRA

The low-density lipoprotein receptor (LDLR) controls cellular delivery of cholesterol and clears LDL from the bloodstream, protecting against atherosclerotic heart disease, the leading cause of death in the United States. We therefore sought to identify regulators of the LDLR beyond the targets of current clinical therapies and known causes of familial hypercholesterolemia. We show that Cold Shock Domain-Containing Protein E1 (CSDE1) enhances hepatic LDLR mRNA decay via its 3' untranslated region and regulates atherogenic lipoproteins in vivo. Using parallel phenotypic genome-wide CRISPR interference screens in a tissue culture model, we found 40 specific regulators of the LDLR left unidentified by observational human genetics. Among these, we show that, in HepG2 cells, CSDE1 regulates the LDLR at least as strongly as the targets exploited by the best available clinical therapies: statins and PCSK9 inhibitors. Additionally, we show that hepatic gene silencing of Csde1 treats diet-induced dyslipidemia in mice similar to that of Pcsk9 silencing. Our results suggest the therapeutic potential of manipulating a newly identified factor in the post-transcriptional regulation of the LDLR mRNA for the prevention of cardiovascular disease. We anticipate that our approach of modeling a clinically relevant phenotype in a forward genetic screen, followed by mechanistic pharmacologic dissection and in vivo validation, will serve as a generalizable template for the identification of therapeutic targets in other human disease states. Overall design: Mice were fed a high-fat (Paigen) diet or standard chow diet and treated and treated with an AAV8-delivered shRNA directed against CSDE1 or a scramble. Mice were subjected to bulk RNA-sequencing (3 CSDE1 and 3 scramble each for Paigen diet and chow diet).