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microRNA‐206 modulates the hepatic expression of the organic anion‐transporting polypeptide 1B1
Author(s) -
El Saadany Tämer,
Rosmalen Belle,
Gai Zhibo,
Hiller Christian,
Verheij Joanne,
Stieger Bruno,
Gulik Thomas,
Visentin Michele,
KullakUblick Gerd A.
Publication year - 2019
Publication title -
liver international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.873
H-Index - 110
eISSN - 1478-3231
pISSN - 1478-3223
DOI - 10.1111/liv.14212
Subject(s) - organic anion transporting polypeptide , microrna , messenger rna , epigenetics , luciferase , gene expression , biology , untranslated region , reporter gene , chemistry , microbiology and biotechnology , transfection , biochemistry , gene , transporter
Background & Aims The organic anion‐transporting polypeptide 1B1 (OATP1B1) is an anion exchanger expressed at the hepatocyte sinusoidal membrane, which mediates the uptake of several endogenous metabolites and drugs. OATP1B1 expression level and activity are major sources of inter‐patient variability of pharmacokinetics and pharmacodynamics of several drugs. Besides the genotype, factors that contribute to the inter‐individual variability in OATP1B1 expression level are practically unknown. The aim of this work was to uncover novel epigenetic mechanisms of OATP1B1 regulation. Methods A functional screening strategy to assess the effect of microRNAs on the uptake of estrone‐3‐sulphate, an OATP1B1 substrate, into human hepatocellular carcinoma (Huh‐7) cells was used. microRNA‐206 (miR‐206) expression in human liver tissues was measured by real‐time RT‐PCR. OATP1B1 expression in Huh‐7 and in human liver tissues was assessed by real‐time RT‐PCR, Western blotting and immunostaining. The mRNA‐miRNA interaction was assessed by reporter assay. Results miR‐206 mimic repressed mRNA and protein expression of OATP1B1 in Huh‐7 cells. The intracellular accumulation of estrone‐3‐sulphate was reduced by 30% in cells overexpressing miR‐206. The repressive effect of miR‐206 on the activity of the firefly luciferase gene 2 under the control of the OATP1B1 3’ untranslated region was lost upon deletion of the predicted miR‐206 binding site. Hepatic miR‐206 level negatively correlated with OATP1B1 mRNA and protein levels extracted from normal human liver tissues. Conclusions miR‐206 exerts a suppressive effect on OATP1B1 expression by an epigenetic mechanism. Individuals with high hepatic levels of miR‐206 appear to display lower level of OATP1B1.