Elevated hepatic multidrug resistance-associated protein... : Hepatology (original) (raw)

Autoimmune, Cholestatic and Biliary Disease

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

Chai, Jin1,‡; He, Yu2,‡; Cai, Shi-Ying3; Jiang, Zhongyong4; Wang, Huaizhi2; Li, Qiong5; Chen, Lei1; Peng, Zhihong1; He, Xiaochong6; Wu, Xiaoping1; Xiao, Tianli1; Wang, Rongquan1; Boyer, James L.3; Chen, Wensheng1,*,†

1 From the Institute of Gastroenterology, Chongqing, China

2 Institute of Hepatobiliary Surgery, Southwest Hospital, Chongqing, China

5 Laboratory and Education Center, College of Basic Medical Science, Chongqing, China

6 School of Nursing, Third Military Medical University, Chongqing, China

4 Department of Clinical Laboratory, General Hospital of PLA Chengdu Military Area Command, Chengdu, China

3 Liver Center, Yale University School of Medicine, New Haven, CT

* Address reprint requests to: Department of Gastroenterology, Southwest Hospital, Third Military Medical University, 29 Gaotanyan Street, Chongqing 400038, China.

E-mail:[email protected]

Received 8 August 2011; Accepted 1 November 2011

Potential conflict of interest: Nothing to report.

This work was supported by the National Natural Science Foundation of China (30570842, 81070320) and the Natural Science Foundation of Chongqing (CQ CSTC 2007BA5030), and J.L.B. and S-Y.C. are supported by National Institutes of Health grants DK R37 25636 and DK P30 34989.

‡ These authors contributed equally to this study.

† fax: 86-23-65410853

View this article online atwileyonlinelibrary.com.

Abstract

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. (Hepatology 2012)