Linked Life Data

17259171

Source:http://linkedlifedata.com/resource/pubmed/id/17259171

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2007-3-19
pubmed:abstractText
The formation of beta-D-glucopyranosides (glucuronides) by the UDP-glucuronosyltransferases (UGTs) is a significant metabolic pathway that facilitates the elimination of small hydrophobic molecules such as drugs, dietary constituents, steroids, and bile acids. We elucidate here that an anti-oxidative response leads to induction of UGT1A1 through the Nrf2-Keap1 pathway. When human HepG2 cells were treated with the prooxidants tert-butylhydroquinone and beta-naphthoflavone, cellular UGT1A1 glucuronidation activities were increased. The induction of UGT1A1 proceeded following the overexpression of Nrf2 and was blocked following overexpression of Keap1, demonstrating that Keap1 suppresses Nrf2 activation of the UGT1A1 gene. Loss of function analysis for Nrf2 conducted by small interfering RNA revealed that induction of UGT1A1 was not seen in Nrf2 knock-out cells. To examine the contribution of oxidants toward the regulation of human UGT1A1 in vivo, transgenic mice bearing the human UGT1 locus (Tg-UGT1) were treated with tert-butylhydroquinone. Human UGT1A1 was markedly increased in small and large intestines as well as in liver. Gene mapping experiments including transfections of UGT1A1 reporter gene constructs into HepG2 cells coupled with functional analysis of Nrf2 expression and binding to anti-oxidant-response elements (ARE) resulted in identification of an ARE in the phenobarbital-response enhancer module region of the UGT1A1 gene. The ARE flanks the recently identified Ah receptor xenobiotic-responsive element. The results suggest that Nrf2-Keap1-dependent UGT1A1 induction by prooxidants might represent a key adaptive response to cellular oxidative stress that defends against a variety of environmental insults, including electrophile attacks and chemical carcinogenesis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Adaptor Proteins, Signal Transducing, http://linkedlifedata.com/resource/pubmed/chemical/Cytoskeletal Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Glucuronidase, http://linkedlifedata.com/resource/pubmed/chemical/Glucuronosyltransferase, http://linkedlifedata.com/resource/pubmed/chemical/Intracellular Signaling Peptides..., http://linkedlifedata.com/resource/pubmed/chemical/KEAP1 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Keap1 protein, mouse, http://linkedlifedata.com/resource/pubmed/chemical/NF-E2-Related Factor 2, http://linkedlifedata.com/resource/pubmed/chemical/Oxidants, http://linkedlifedata.com/resource/pubmed/chemical/Phenobarbital, http://linkedlifedata.com/resource/pubmed/chemical/bilirubin...
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8749-58
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Nrf2-Keap1 signaling pathway regulates human UGT1A1 expression in vitro and in transgenic UGT1 mice.
pubmed:affiliation
Laboratory of Environmental Toxicology, Department of Chemistry, University of California, San Diego, La Jolla, California 92093, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural