Document Detail


Interaction of hepatocyte nuclear factors in transcriptional regulation of tissue specific hormonal expression of human multidrug resistance-associated protein 2 (abcc2).
MedLine Citation:
PMID:  19010343     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Multidrug resistance-associated protein 2 (MRP2) (ABCC2) is an ATP-binding cassette membrane protein located primarily on apical surface of hepatocytes that mediates transport of conjugated xenobiotics and endogenous compounds into bile. MRP2 is highly expressed in hepatocytes, and at lower levels in small intestines, stomach and kidney. Previous reports have characterized mammalian MRP2 promoters, but none have established the molecular mechanism(s) involved in liver enriched expression. This study aims to investigate the mechanism of hepatic MRP2 regulation. A 2130 bp of MRP2 promoter was cloned from PAC-1 clone P108G1-7, to identify putative liver specific/hormone responsive functional DNA binding sites. Using deletion analysis, site specific mutagenesis and co-transfection studies, liver specific expression was determined. MRP2 promoter-LUC constructs were highly expressed in liver cell lines compared to non-liver cells. The region extending from -3 to+458 bp of MRP2 promoter starting from AUG contained the potential binding sites for CAATT box enhancer binding protein (C/EBP), hepatocytes nuclear factor 1, 3 and 4 (HNF1, HNF3, and HNF4. Only HNF1 and HNF4 co-transfection with MRP2 luciferase increased expression. Site specific mutational analysis of HNF1 binding site indicated an important role for HNF1alpha. HNF4alpha induction of MRP2 was independent of HNF1 binding site. C/EBP, HNF3, and HNF6 inhibited HNF1alpha while HNF4alpha induced MRP2 luciferase expression and glucocorticoids stimulated MRP2 expression. This study emphasizes the complex regulation of MRP2 with HNF1alpha and HNF4alpha playing a central role. The coordinated regulation of xenobiotic transporters and oxidative conjugation may determine the adaptive responses to cellular detoxification processes.
Authors:
Ishtiaq Qadri; Ling-Jia Hu; Mieko Iwahashi; Subhi Al-Zuabi; Linda C Quattrochi; Francis R Simon
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2008-10-29
Journal Detail:
Title:  Toxicology and applied pharmacology     Volume:  234     ISSN:  1096-0333     ISO Abbreviation:  Toxicol. Appl. Pharmacol.     Publication Date:  2009 Feb 
Date Detail:
Created Date:  2009-02-02     Completed Date:  2009-02-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0416575     Medline TA:  Toxicol Appl Pharmacol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  281-92     Citation Subset:  IM    
Affiliation:
NUST Center of Virology and Immunology, National University of Science and Technology, Tamizudin Road, Rawalpindi, Pakistan. dg-ncvi@nust.edu.pk
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MeSH Terms
Descriptor/Qualifier:
5' Flanking Region
ATP-Binding Cassette Transporters / genetics,  metabolism*
Animals
Base Sequence
CCAAT-Enhancer-Binding Proteins / metabolism
CHO Cells
Cloning, Molecular
Cricetinae
Cricetulus
Dexamethasone / pharmacology*
Genes, Reporter
Glucocorticoids / pharmacology*
Hela Cells
Hepatocyte Nuclear Factor 1-alpha / metabolism
Hepatocyte Nuclear Factor 4 / metabolism
Hepatocyte Nuclear Factor 6 / metabolism
Hepatocyte Nuclear Factors / genetics,  metabolism*
Hepatocytes / drug effects*,  metabolism
Humans
Molecular Sequence Data
Multidrug Resistance-Associated Proteins / genetics,  metabolism*
Mutagenesis, Site-Directed
Promoter Regions, Genetic / drug effects*
Rats
Transcription, Genetic / drug effects*
Transfection
Grant Support
ID/Acronym/Agency:
DK-15851/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/ATP-Binding Cassette Transporters; 0/Abcc2 protein, rat; 0/CCAAT-Enhancer-Binding Proteins; 0/Glucocorticoids; 0/Hepatocyte Nuclear Factor 1-alpha; 0/Hepatocyte Nuclear Factor 4; 0/Hepatocyte Nuclear Factor 6; 0/Hepatocyte Nuclear Factors; 0/Multidrug Resistance-Associated Proteins; 0/multidrug resistance-associated protein 2; 50-02-2/Dexamethasone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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