Linked Life Data

16672736

Source:http://linkedlifedata.com/resource/pubmed/id/16672736

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2006-8-2
pubmed:abstractText
Glucosamine-induced endoplasmic reticulum (ER) stress was recently shown to specifically reduce apolipoprotein B-100 (apoB-100) secretion by enhancing the proteasomal degradation of apoB-100. Here, we examined the mechanisms linking glucosamine-induced ER stress and apoB-lipoprotein biogenesis. Trypsin sensitivity studies suggested glucosamine-induced changes in apoB-100 conformation. Endoglycosidase H studies of newly synthesized apoB-100 revealed glucosamine induced N-linked glycosylation defects resulting in reduced apoB-100 secretion. We also examined glucosamine-induced changes in VLDL assembly and secretion. A dose-dependent (1-10 mM glucosamine) reduction was observed in VLDL-apoB-100 secretion in primary hepatocytes (24.2-67.3%) and rat McA-RH7777 cells (23.2-89.5%). Glucosamine also inhibited the assembly of larger VLDL-, LDL-, and intermediate density lipoprotein-apoB-100 but did not affect smaller HDL-sized apoB-100 particles. Glucosamine treatment during the chase period (posttranslational) led to a 24% reduction in apoB-100 secretion (P < 0.01; n = 4) and promoted post-ER apoB degradation. However, the contribution of post-ER apoB-100 degradation appeared to be quantitatively minor. Interestingly, the glucosamine-induced posttranslational reduction in apoB-100 secretion could be partially prevented by treatment with desferrioxamine or vitamin E. Together, these data suggest that cotranslational glucosamine treatment may cause defects in apoB-100 N-linked glycosylation and folding, resulting in enhanced proteasomal degradation. Posttranslationally, glucosamine may interfere with the assembly process of apoB lipoproteins, leading to post-ER degradation via nonproteasomal pathways.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-2275
pubmed:author
pubmed:issnType
Print
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1749-61
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Mechanisms of glucosamine-induced suppression of the hepatic assembly and secretion of apolipoprotein B-100-containing lipoproteins.
pubmed:affiliation
Department of Clinical Biochemistry and Pathobiology, Division of Clinical Biochemistry, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't