학술논문
Posttranscriptional Regulation of the Human LDL Receptor by the U2-Spliceosome
Document Type
Electronic Resource
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Source
Zanoni , P , Panteloglou , G , Othman , A , Haas , J T , Meier , R , Rimbert , A , Futema , M , Khalil , Y A , Norrelykke , S F , Rzepiela , A J , Stoma , S , Stebler , M , Van Dijk , F , Wijers , M , Wolters , J C , Dalila , N , Huijkman , N C A , Smit , M , Gallo , A , Carreau , V , Philippi , A , Rabès , J P , Boileau , C , Visentin , M , Vonghia , L , Weyler , J , Francque , S , Verrijken , A , Verhaegen , A , Van Gaal , L , Van Der Graaf , A , Van Rosmalen , B V , Robert , J , Velagapudi , S , Yalcinkaya , M , Keel , M , Radosavljevic , S , Geier , A , Tybjaerg-Hansen , A , Varret , M , Rohrer , L , Humphries , S E , Staels , B , Van De Sluis , B , Kuivenhoven , J A & Von Eckardstein , A 2022 , ' Posttranscriptional Regulation of the Human LDL Receptor by the U2-Spliceosome ' , Circulation Research , vol. 130 , no. 1 , pp. 80-95 .
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Language
Abstract
BACKGROUND: The LDLR (low-density lipoprotein receptor) 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 data sets 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 nontransfected cells nor in human plasma. The hepatic expression of the intron 3 retention transcript is increased in nonalcoholic fatty liver disease as well as after bariatric surgery. Its expression in blood cells correlates with LDL-cholesterol and age. Single nucleotide polymorphisms and 3 rare variants of one spliceosome gene, RBM25, are associated with LDL-cholesterol in the population and familial hypercholesterolemia, respectively. Compared with overexpression of wild-type RBM25, overexpression of the 3 rare RBM25 mutants in Huh-7 cells led to lower LDL uptake. CONCLUSIONS: We identified a novel mechanism of posttranscriptional regulation of LDLR activity in humans and associations of genetic variants of RBM25 with LDL-cholesterol levels.