Linked Life Data

8690404

Source:http://linkedlifedata.com/resource/pubmed/id/8690404

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1996-8-29
pubmed:abstractText
During liver fibrogenesis, Ito cells are regarded as the principal matrix synthesizing cells and transforming growth factor beta 1 (TGF-beta 1) appears to be the main fibrogenic mediator. This study analyzed the effects of TGF-beta 1 on Ito cell activation, proliferation, and on the expression of a set of matrix proteins, antiproteases, and TGF-beta receptors both in "early cultured" and "culture-activated" Ito cells. Rat liver Ito cells at day 2 of primary culture ("early cultured" cells) were mainly smooth muscle alpha actin (SMA)-negative, whereas cells at day 6 were judged as "activated" cells (SMA-positive). Following 24-hour exposure to 1 ng/mL TGF-beta 1, total protein synthesis, cell proliferation, and expression of the "activation" marker SMA were not significantly changed. In addition to previously described stimulatory effects on collagen types I and III, fibronectin, undulin, and proteoglycan-gene expression, TGF-beta also dose-dependently increased synthesis and secretion of tenascin, laminin, entactin, collagen type IV, and alpha 2-macroglobulin, but decreased C1-esterase inhibitor production by Ito cells, as revealed by immunoprecipitation of endogenously labeled proteins and by Northern blot analysis. The stimulatory effect of TGF-beta was evident both in "early cultured" as well as "culture-activated" Ito cells. By reverse-transcription polymerase chain reaction (RT-PCR) analysis, TGF-beta type II, III, and TGF-beta/activin type I receptors were present in Ito cells, and their expression pattern was not changed upon TGF-beta exposure. Northern blot analysis demonstrated that type I TGF-beta/activin receptor was induced during in vitro activation and that TGF-beta exposure resulted in a slight increase of type I and III receptor messenger RNAs. In summary, the data illustrate that TGF-beta is an important fibrogenic mediator acting both on "early cultured" as well as "culture-activated" Ito cells, rather than a mitogenic or morphogenic mediator. The differential regulation of TGF-beta/activin receptors during in vitro activation and their up-regulation by TGF-beta 1 might represent a mechanism by which the receptor complex regulates TGF-beta signalling in Ito cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0270-9139
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
352-60
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Transforming growth factor beta 1-regulated gene expression of Ito cells.
pubmed:affiliation
Department of Internal Medicine, University of Göttingen, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't