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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
Author(s) -
Chai Jin,
He Yu,
Cai ShiYing,
Jiang Zhongyong,
Wang Huaizhi,
Li Qiong,
Chen Lei,
Peng Zhihong,
He Xiaochong,
Wu Xiaoping,
Xiao Tianli,
Wang Rongquan,
Boyer James L.,
Chen Wensheng
Publication year - 2012
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.24801
Subject(s) - cholestasis , subfamily , cancer research , tumor necrosis factor alpha , atp binding cassette transporter , multiple drug resistance , abcg2 , kinase , chemistry , biology , microbiology and biotechnology , medicine , drug resistance , gene , biochemistry , transporter , genetics
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. (H EPATOLOGY 2012)