Linked Life Data

8706787

Source:http://linkedlifedata.com/resource/pubmed/id/8706787

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1996-9-11
pubmed:abstractText
Fibroblast senescence is associated with a loss of proliferative potential and an alteration in extracellular gene expression. Because the expression of extracellular gene products are frequently growth state dependent, we undertook a comparative study of the regulation of the components of the plasminogen activation system in young and senescent cells under controlled conditions of growth. Young and senescent cells were compared in quiescent and activated growth conditions for the secretion of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitor-1 (PAI-1) and plasminogen activator inhibitor-2 (PAI-2). Whereas young cells showed decreased levels of PAI-1 in the secreted and extracellular matrix pools upon serum deprivation, senescent cells showed a more constitutive pattern of gene expression, with no noticeable decrease of the levels in a low concentration of serum. RNA analysis revealed that senescent lung and skin cells, independent of the growth state, constitutively express levels of u-PA and PAI-1 comparable to the expression levels in young mitotically growing cells. These expression levels are down-regulated in quiescent young cells. In contrast, both t-PA and PAI-2 were markedly overexpressed in senescent skin lung cells under all growth conditions. Total plasminogen activator activity in conditioned medium was 50-fold higher in senescent-cell medium compared to young when cultured in 0.5% fetal calf serum (FCS) for five days, with the majority of the activity co-migrating on zymograms with u-PA. Increases in PAI-1 was also observed in senescent human umbilical vein endothelial cells. In summary, cells of various types display alterations in plasminogen activator activity during replicative senescence. The inappropriate over-expression of plasminogen activator activity in vivo may be expected to lead to a progressive disruption of extracellular matrix maintenance. Thus, our observations suggest that cellular replicative senescence is associated with an altered expression of several genes regulating tissue maintenance which, in turn, could lead to degenerative changes in tissue in age-related disease(s).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0531-5565
pubmed:author
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
175-93
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:articleTitle
Altered expression of plasminogen activator and plasminogen activator inhibitor during cellular senescence.
pubmed:affiliation
Geron Corporation, Menlo Park, CA 94025, USA.
pubmed:publicationType
Journal Article