Document Detail


Docosahexaenoic acid downregulates phenobarbital-induced cytochrome P450 2B1 gene expression in rat primary hepatocytes via the c-Jun NH2-terminal kinase mitogen-activated protein kinase pathway.
MedLine Citation:
PMID:  18803253     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Mitogen-activated protein kinase (MAPK) pathways play central roles in the transduction of extracellular stimuli into cells and the regulation of expression of numerous genes. Docosahexaenoic acid (DHA) was shown to be involved in the regulation of expression of drug metabolizing enzymes (DMEs) in rat primary hepatocytes in response to xenobiotics. Cytochrome P450 2B1 (CYP 2B1) is a DME that is dramatically induced by phenobarbital-type inducers. The constitutive androstane receptor (CAR) plays a critical role in regulating the expression of DMEs, and the phosphorylation/dephosphorylation of CAR is an important event in CYP 2B1 expression. In the present study, we determined the effect of DHA on MAPK transactivation and its role in CYP 2B1 expression induced by phenobarbital. c-Jun NH2-terminal kinase (JNK) JNK1/2 and ERK1/2 were activated by phenobarbital in a dose-dependent manner. DHA (100 muM) inhibited JNK1/2 and ERK2 activation induced by phenobarbital in a time-dependent manner. Both SP600125 (a JNK inhibitor) and SB203580 (a p38 MAPK inhibitor) inhibited CYP 2B1 protein and mRNA expression induced by phenobarbital. SB203580 significantly increased the intracellular 3'-5'-cyclic adenosine monophosphate (cAMP) concentration compared with a control group (p < 0.05). Our results suggest that inhibition of JNK activation by DHA is at least part of the mechanisms of DHA's downregulation of CYP 2B1 expression induced by phenobarbital.
Authors:
Chia-Yang Lu; Chien-Chun Li; Kai-Li Liu; Chong-Kuei Lii; Haw-Wen Chen
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Molecular nutrition & food research     Volume:  53     ISSN:  1613-4133     ISO Abbreviation:  Mol Nutr Food Res     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-03-10     Completed Date:  2009-06-15     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  101231818     Medline TA:  Mol Nutr Food Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  341-8     Citation Subset:  IM    
Affiliation:
Department of Nutrition, Chung Shan Medical University, Taichung, Taiwan, ROC.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cells, Cultured
Cyclic AMP / analysis
Cytochrome P-450 CYP2B1 / antagonists & inhibitors,  genetics*
Docosahexaenoic Acids / pharmacology*
Down-Regulation / drug effects*
Enzyme Activation / drug effects
Enzyme Induction / drug effects
Enzyme Inhibitors / pharmacology
Gene Expression / drug effects
Hepatocytes / chemistry,  enzymology*
JNK Mitogen-Activated Protein Kinases / antagonists & inhibitors,  metabolism*
Male
Mitogen-Activated Protein Kinases / antagonists & inhibitors,  metabolism
Phenobarbital / pharmacology*
RNA, Messenger / analysis
Rats
Rats, Sprague-Dawley
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 0/RNA, Messenger; 25167-62-8/Docosahexaenoic Acids; 50-06-6/Phenobarbital; 60-92-4/Cyclic AMP; EC 1.14.14.1/Cytochrome P-450 CYP2B1; EC 2.7.11.24/JNK Mitogen-Activated Protein Kinases; EC 2.7.11.24/Mitogen-Activated Protein Kinases

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


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