학술논문
Posttranscriptional Regulation of the Human LDL Receptor by the U2-Spliceosome
Document Type
Academic Journal
Author
Zanoni, Paolo; Panteloglou, Grigorios; Othman, Alaa; Haas, Joel T.; Meier, Roger; Rimbert, Antoine; Futema, Marta; Khalil, Yara Abou; Norrelykke, Simon F.; Rzepiela, Andrzej J.; Stoma, Szymon; Stebler, Michael; van Dijk, Freerk; Wijers, Melinde; Wolters, Justina C.; Dalila, Nawar; Huijkman, Nicolette C. A.; Smit, Marieke; Gallo, Antonio; Carreau, Valérie; Philippi, Anne; Rabès, Jean- Pierre; Boileau, Catherine; Visentin, Michele; Vonghia, Luisa; Weyler, Jonas; Francque, Sven; Verrijken, An; Verhaegen, Ann; Van Gaal, Luc; van der Graaf, Adriaan; van Rosmalen, Belle V.; Robert, Jerome; Velagapudi, Srividya; Yalcinkaya, Mustafa; Keel, Michaela; Radosavljevic, Silvija; Geier, Andreas; Tybjaerg-Hansen, Anne; Varret, Mathilde; Rohrer, Lucia; Humphries, Steve E.; Staels, Bart; van de Sluis, Bart; Kuivenhoven, Jan Albert; von Eckardstein, Arnold
Source
Circulation Research. Nov 29, 2021
Subject
Language
English
ISSN
0009-7330
Abstract
BACKGROUND:: The low-density lipoprotein receptor (LDLR) in the liver is the major determinant of LDL- cholesterol levels in human plasma. The discovery of genes that regulate the activity of LDLR helps to identify pathomechanisms of hypercholesterolemia and novel therapeutic targets against atherosclerotic cardiovascular disease. METHODS:: We performed a genome-wide RNA interference screen for genes limiting the uptake of fluorescent LDL into Huh-7 hepatocarcinoma cells. Top hit genes were validated by in vitro experiments as well as analyses of datasets on gene expression and variants in human populations. RESULTS:: The knockdown of 54 genes significantly inhibited LDL uptake. Fifteen of them encode for components or interactors of the U2-spliceosome. Knocking down any one of 11 out of 15 genes resulted in the selective retention of intron 3 of LDLR. The translated LDLR fragment lacks 88% of the full length LDLR and is detectable neither in non-transfected cells nor in human plasma. The hepatic expression of the intron 3 retention transcript is increased in non-alcoholic fatty liver disease as well as after bariatric surgery. Its expression in blood cells correlates with LDL-cholesterol and age. Single nucleotide polymorphisms and three rare variants of one spliceosome gene, RBM25, are associated with LDL- cholesterol in the population and familial hypercholesterolemia, respectively. Compared to overexpression of wild type RBM25, overexpression of the three rare RBM25 mutants in Huh-7 cells led to lower LDL uptake. CONCLUSIONS:: We identified a novel mechanism of post-transcriptional regulation of LDLR activity in humans and associations of genetic variants of RBM25 with LDL-cholesterol levels.