Linked Life Data

15543932

Source:http://linkedlifedata.com/resource/pubmed/id/15543932

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
2004-11-16
pubmed:abstractText
Iron may populate distinct hepatocellular iron pools that differentially regulate expression of proteins such as ferritin and transferrin receptor (TfR) through iron-regulatory mRNA-binding proteins (IRPs), and may additionally regulate uptake and accumulation of non-transferrin-bound iron (NTBI). We examined iron-regulatory protein (IRP) binding activity and ferritin/TfR expression in human hepatoma (HepG2) cells exposed to iron at different levels for different periods. Several iron-dependent RNA-binding activities were identified, but only IRP increased with beta-mercaptoethanol. With exposures between 0 and 20 microg/ml iron, decreases in IRP binding accompanied large changes in TfR and ferritin expression, while chelation of residual iron with deferoxamine (DFO) caused a large increase in IRP binding with little additional effect on TfR or ferritin expression. Cellular iron content increased beyond 4 days of exposure to iron at 20 microg/ml, when IRP binding, TfR, and ferritin had all reached stable levels. However, iron content of the cells plateaued by 7 days, or decreased with 24 h exposure to very high concentrations (>50 microg/ml) of iron. These results indicate that iron-replete HepG2 cells exhibit a narrow range of maximal responsiveness of the IRP-regulatory mechanism, whose functional response is blunted both by excessive iron exposure and by removal of iron from a chelatable pool. HepG2 cells are able to limit iron accumulation upon higher or prolonged exposure to NTBI, apparently independent of the IRP mechanism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0300-8177
pubmed:author
pubmed:issnType
Print
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
37-45
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Iron accumulation and iron-regulatory protein activity in human hepatoma (HepG2) cells.
pubmed:affiliation
Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ont., Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't