Linked Life Data

3192617

Source:http://linkedlifedata.com/resource/pubmed/id/3192617

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1988-12-29
pubmed:abstractText
Sialic acids, occupying a terminal position in cell surface glycoconjugates, are major contributors to the net negative charge of the vascular endothelial cell surface. As integral membrane glycoproteins, LDL receptors also bear terminal sialic acid residues. Pretreatment of near-confluent, cultured bovine aortic endothelial cells (BAEC) with neuraminidase (50 mU/ml, 30 min, 37 degrees C) stimulated a significant increase in receptor-mediated 125I-LDL internalization and degradation relative to PBS-treated control cells. Binding studies at 4 degrees C revealed an increased affinity of LDL receptor sites on neuraminidase-treated cells compared to control BAEC (6.9 vs. 16.2 nM/10(6) BAEC) without a change in receptor site number. This enhanced LDL endocytosis in neuraminidase-treated cells was dependent upon the enzymatic activity of the neuraminidase and the removal of sialic acid from the cell surface. Furthermore, enhanced endocytosis due to enzymatic alteration of the 125I-LDL molecules was excluded. In contrast to BAEC, neuraminidase pretreatment of LDL receptor-upregulated cultured normal human fibroblasts resulted in an inhibition of 125I-LDL binding, internalization, and degradation. Specifically, a significant inhibition in 125I-LDL internalization was observed at 1 hr after neuraminidase treatment, which was associated with a decrease in the number of cell surface LDL receptor sites. Like BAEC, neuraminidase pretreatment of human umbilical vein endothelial cells resulted in enhanced receptor-mediated 125I-LDL endocytosis. These results indicate that sialic acid associated with either adjacent endothelial cell surface molecules or the endothelial LDL receptor itself may modulate LDL receptor-mediated endocytosis and suggest that this regulatory mechanism may be of particular importance to endothelial cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9541
pubmed:author
pubmed:issnType
Print
pubmed:volume
137
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
251-62
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Stimulation of receptor-mediated low density lipoprotein endocytosis in neuraminidase-treated cultured bovine aortic endothelial cells.
pubmed:affiliation
Department of Pathology, University of Texas Health Science Center, San Antonio 78284.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.