Elevated hepatic multidrug resistance-associated protein 3/ATP-binding cassette subfamily C 3 expression in human obstructive cholestasis is mediated through tumor necrosis factor alpha and c-Jun NH2-terminal kinase/stress-activated protein kinase-signaling pathway.

Abstract

UNLABELLED:

Multidrug resistance-associated protein 3 (MRP3, ABC subfamily C [ABCC]3) plays an important role in protecting hepatocytes and other tissues by excreting an array of toxic organic anion conjugates, including bile salts. MRP3/ABCC3 expression is increased in the liver of some cholestatic patients, but the molecular mechanism of this up-regulation remains elusive. In this report, we assessed liver MRP3/ABCC3 expression in patients (n = 22) with obstructive cholestasis caused by gallstone blockage of bile ducts and noncholestatic patient controls (n = 22). MRP3/ABCC3 messenger RNA (mRNA) and protein expression were significantly increased by 3.4- and 4.6-fold, respectively, in these cholestatic patients where elevated plasma tumor necrosis factor alpha (TNFα) (4.7-fold; P < 0.01) and hepatic specificity protein 1 transcription factor (SP1) and liver receptor homolog 1 expression (3.1- and 2.1-fold at mRNA level, 3.5- and 2.5-fold at protein level, respectively) were also observed. The induction of hepatic MRP3/ABCC3 mRNA expression is significantly positively correlated with the level of plasma TNFα in these patients. In HepG2 cells, TNFα treatment induced SP1 and MRP3/ABCC3 expression in a dose- and time-dependent manner, where increased phosphorylation of c-Jun NH2-terminal kinase/stress-activated protein kinase (JNK/SAPK) was also detected. These inductions were significantly reduced in the presence of the JNK inhibitor, SP600125. TNFα treatment enhanced HepG2 cell nuclear extract-binding activity to the MRP3/ABCC3 promoter, but was abolished by SP600125, as demonstrated by electrophoretic mobility shift assay (EMSA). An increase in nuclear protein-binding activity to the MRP3/ABCC3 promoter, consisting primarily of SP1, was also observed in liver samples from cholestatic patients, as assessed by supershift EMSA assays.

CONCLUSIONS:

Our findings indicate that up-regulation of hepatic MRP3/ABCC3 expression in human obstructive cholestasis is likely triggered by TNFα, mediated by activation of JNK/SAPK and SP1.

• Authors: Jin Chai, Yu He, Shi-Ying Cai, Zhongyong Jiang, Huaizhi Wang, Qiong Li, Lei Chen, Zhihong Peng, Xiaochong He, Xiaoping Wu, Tianli Xiao, Rongquan Wang, James L Boyer, Wensheng Chen
• Journal: Hepatology (Baltimore, Md.) (Hepatology) Vol. 55 Issue 5 Pg. 1485-94 (May 2012) ISSN: 1527-3350 [Electronic] United States
• PMID: 22105759 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 American Association for the Study of Liver Diseases.

Chemical References

• Multidrug Resistance-Associated Proteins
• RNA, Messenger
• Sp1 Transcription Factor
• Tumor Necrosis Factor-alpha
• multidrug resistance-associated protein 3
• JNK Mitogen-Activated Protein Kinases

Topics

• Adult
• Biopsy, Needle
• Blotting, Western
• Case-Control Studies
• Cholestasis (genetics, metabolism, pathology)
• Disease Progression
• Female
• Fluorescent Antibody Technique
• Gene Expression Regulation
• Humans
• JNK Mitogen-Activated Protein Kinases (genetics, metabolism)
• Male
• Middle Aged
• Multidrug Resistance-Associated Proteins (genetics, metabolism)
• RNA, Messenger (metabolism)
• Real-Time Polymerase Chain Reaction (methods)
• Sensitivity and Specificity
• Signal Transduction
• Sp1 Transcription Factor (metabolism)
• Tissue Culture Techniques
• Tumor Cells, Cultured (drug effects)
• Tumor Necrosis Factor-alpha (blood, metabolism)
• Up-Regulation