Linked Life Data

8530509

Source:http://linkedlifedata.com/resource/pubmed/id/8530509

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
1996-1-30
pubmed:abstractText
Recently the sphingomyelin cycle, involving the hydrolysis of membrane sphingomyelin by an activated sphingomyelinase to generate ceramide, has emerged as a key pathway in cell differentiation and apoptosis in leukemic and other cell types. Here we investigate a role for this pathway in the senescence of WI-38 human diploid fibroblasts (HDF). We found that endogenous levels of ceramide increased considerably (4-fold) and specifically (compared with other lipids) as cells entered the senescent phase. Investigation of the mechanism of increased ceramide led to the discovery that neutral sphingomyelinase activity is elevated 8-10 fold in senescent cells. There were no changes in sphingomyelinase activity or ceramide levels as HDF entered quiescence following serum withdrawal or contact inhibition. Thus, the activation of the sphingomyelinase/ceramide pathway in HDF is due to senescence and supports the hypotheses that senescence represents a distinct program of cell development that can be differentiated from quiescence. Additional studies disclosed the ability of ceramide to induce a senescent phenotype. Thus, when exogenous ceramide (15 microM) was administered to young WI-38 HDF, it produced endogenous levels comparable to those observed in senescent cells (as determined by metabolic labeling studies). Ceramide concentrations of 10-15 microM inhibited the growth of young HDF and induced a senescent phenotype by its ability to inhibit DNA synthesis and mitogenesis. These concentrations of ceramide also induced retinoblastoma dephosphorylation and inhibited serum-induced AP-1 activation in young HDF, thus recapitulating basic biochemical and molecular changes of senescence. Sphingomyelinase and ceramide may thus be implicated as mediators of cellular senescence.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
30701-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Role of ceramide in cellular senescence.
pubmed:affiliation
Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.