Linked Life Data

7601419

Source:http://linkedlifedata.com/resource/pubmed/id/7601419

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-8-9
pubmed:abstractText
Injury-related cytokines, such as tumor necrosis factor-alpha (TNF), may preserve liver-specific gene expression during the subsequent regenerative response by modulating the activity of transcription factors, including CCAAT/enhancer binding proteins (C/EBPs), which regulate differentiated gene expression in hepatocytes. To test this theory, rats were treated with neutralizing antibody to TNF or nonimmune immunoglobulin before partial hepatectomy (PH) and regenerative changes in the messenger RNAs (mRNAs), proteins, and DNA-binding activities of C/EBP isoforms and the expression of a C/EBP-regulated gene, phosphoenol pyruvate carboxykinase (PEPCK), were compared. Before PH, the expressions of C/EBP-alpha, C/EBP-beta, and C/EBP-gamma were similar in the two treatment groups. Dimers containing C/EBP-alpha and C/EBP-beta accounted for virtually all of the C/EBP DNA binding activity and mRNA for PEPCK, the rate limiting hepatocyte enzyme for gluconeogenesis, was barely detected. After PH, in control rats, mRNA and nuclear protein concentrations of C/EBP-beta and C/EBP-gamma increased approximately fivefold by 3 hours after PH. This was accompanied by increased DNA binding activity of these C/EBP isoforms and decreased DNA binding activity of C/EBP-alpha. mRNA levels of PEPCK, a gene that is strongly transactivated by non-alpha C/EBP isoforms, increased fivefold. Pretreatment with anti-TNF antibodies prevented regenerative induction of C/EBP beta and gamma expression and DNA-binding activity. The nature of dimers binding to C/EBP cis-acting elements remained similar to that observed in liver before PH and increases in PEPCK mRNA were blunted. These results support the theory that TNF helps maintain liver-specific gene expression during liver regeneration by altering transcription factor complexes that regulate differentiated gene expression in hepatocytes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0270-9139
pubmed:author
pubmed:issnType
Print
pubmed:volume
22
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
252-61
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Tumor necrosis factor-alpha modulates CCAAT/enhancer binding proteins-DNA binding activities and promotes hepatocyte-specific gene expression during liver regeneration.
pubmed:affiliation
Department of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.