OBJECTIVES: Our aims were to identify and functionally characterize coding region nonsynonymous single nucleotide polymorphisms in the hepatic efflux transporter, bile salt export pump (BSEP; ABCB11), and to assess interindividual variability in BSEP expression. METHODS: We identified 24 single nucleotide polymorphisms, including nine nonsynonymous variants, in ABCB11 from genomic DNA of approximately 250 ethnically diverse healthy individuals using denaturing high-performance liquid chromatography analysis and DNA sequencing. Wild type and variant BSEP were generated and functionally characterized for taurocholate transport activity in vitro in HeLa cells using a recombinant vaccinia-based method. BSEP expression was assessed by real-time mRNA analysis, western blot analysis, and immunofluorescence confocal microscopy. RESULTS: For the most part, polymorphisms were rare and ethnic-dependent. In vitro functional studies revealed several rare variants, including 616A>G, 1674G>C, 1772A>G, and 3556G>A, to be associated with significantly impaired taurocholate transport activity while the 890A>G variant trended towards impaired function but was not statistically significant. The 3556G>A variant was associated with reduced cell surface to total protein expression compared with wild-type BSEP. Expression of BSEP by mRNA and protein analysis was determined from a bank of human liver samples. Wide interindividual variability was noted in both mRNA (19-fold) and protein (31-fold) expression levels. The common variant 1331T>C was associated with significantly reduced hepatic BSEP mRNA levels. CONCLUSION: Accordingly, our study indicates there are functionally relevant polymorphisms in ABCB11 which may be of potential relevance in the predisposition to acquired liver disorders such as drug-induced cholestasis.
OBJECTIVES: Our aims were to identify and functionally characterize coding region nonsynonymous single nucleotide polymorphisms in the hepatic efflux transporter, bile salt export pump (BSEP; ABCB11), and to assess interindividual variability in BSEP expression. METHODS: We identified 24 single nucleotide polymorphisms, including nine nonsynonymous variants, in ABCB11 from genomic DNA of approximately 250 ethnically diverse healthy individuals using denaturing high-performance liquid chromatography analysis and DNA sequencing. Wild type and variant BSEP were generated and functionally characterized for taurocholate transport activity in vitro in HeLa cells using a recombinant vaccinia-based method. BSEP expression was assessed by real-time mRNA analysis, western blot analysis, and immunofluorescence confocal microscopy. RESULTS: For the most part, polymorphisms were rare and ethnic-dependent. In vitro functional studies revealed several rare variants, including 616A>G, 1674G>C, 1772A>G, and 3556G>A, to be associated with significantly impaired taurocholate transport activity while the 890A>G variant trended towards impaired function but was not statistically significant. The 3556G>A variant was associated with reduced cell surface to total protein expression compared with wild-type BSEP. Expression of BSEP by mRNA and protein analysis was determined from a bank of human liver samples. Wide interindividual variability was noted in both mRNA (19-fold) and protein (31-fold) expression levels. The common variant 1331T>C was associated with significantly reduced hepatic BSEP mRNA levels. CONCLUSION: Accordingly, our study indicates there are functionally relevant polymorphisms in ABCB11 which may be of potential relevance in the predisposition to acquired liver disorders such as drug-induced cholestasis.
Authors: P L Jansen; S S Strautnieks; E Jacquemin; M Hadchouel; E M Sokal; G J Hooiveld; J H Koning; A De Jager-Krikken; F Kuipers; F Stellaard; C M Bijleveld; A Gouw; H Van Goor; R J Thompson; M Müller Journal: Gastroenterology Date: 1999-12 Impact factor: 22.682
Authors: S S Strautnieks; L N Bull; A S Knisely; S A Kocoshis; N Dahl; H Arnell; E Sokal; K Dahan; S Childs; V Ling; M S Tanner; A F Kagalwalla; A Németh; J Pawlowska; A Baker; G Mieli-Vergani; N B Freimer; R M Gardiner; R J Thompson Journal: Nat Genet Date: 1998-11 Impact factor: 38.330
Authors: Anne S Henkel; Mark H Kavesh; Michael S Kriss; Amanda M Dewey; Mary E Rinella; Richard M Green Journal: Gastroenterology Date: 2011-07-02 Impact factor: 22.682
Authors: S M Markova; T De Marco; N Bendjilali; E A Kobashigawa; J Mefford; J Sodhi; H Le; C Zhang; J Halladay; A E Rettie; C Khojasteh; D McGlothlin; A H B Wu; W-C Hsueh; J S Witte; J B Schwartz; D L Kroetz Journal: Clin Pharmacol Ther Date: 2013-07-17 Impact factor: 6.875
Authors: Mariana Ferreira Cardoso; Joana Carvalho E Branco; Vera Anapaz; Catarina Graça Rodrigues; Rita Carvalho; David Horta; Alexandra Martins; Jorge Reis Journal: GE Port J Gastroenterol Date: 2017-11-25