Linked Life Data

16650751

Source:http://linkedlifedata.com/resource/pubmed/id/16650751

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-12-4
pubmed:abstractText
Bone is continuously remodeled through resorption by osteoclasts and the subsequent synthesis of the bone matrix by osteoblasts. Cell-to-cell contact between osteoblasts and osteoclast precursors is required for osteoclast formation. RANKL (receptor activator of nuclear factor-kappaB ligand) expressed on osteoblastic cell membranes stimulates osteoclastogenesis, while osteoprotegerin (OPG) secreted by osteoblasts inhibits osteoclastogenesis. Although polyunsaturated fatty acids (PUFAs) have been implicated in bone homeostasis, the effects thereof on OPG and RANKL secretion have not been investigated. MC3T3-E1 osteoblasts were exposed to the n-6 PUFA arachidonic acid (AA) and the n-3 PUFA docosahexaenoic acid (DHA); furthermore, the bone-active hormone parathyroid hormone (PTH) and the effects thereof were tested on OPG and RANKL secretion. Prostaglandin E(2) (PGE(2)), a product of AA metabolism that was previously implicated in bone homeostasis, was included in the study. AA (5.0-20 microg/ml) inhibited OPG secretion by 25-30%, which was attenuated by pretreatment with the cyclooxygenase blocker indomethacin, suggesting that the inhibitory effect of AA on OPG could possibly be PGE(2)-mediated. MC3T3-E1 cells secreted very low basal levels of RANKL, but AA stimulated RANKL secretion, thereby decreasing the OPG/RANKL ratio. DHA suppressed OPG secretion to a smaller extent than AA. This could, however, be due to endogenous PGE(2) production. No RANKL could be detected after exposing the MC3T3-E1 cells to DHA. PTH did not affect OPG secretion, but stimulated RANKL secretion. This study demonstrates that AA and PTH reduce the OPG/RANKL ratio and may increase osteoclastogenesis. DHA, however, had no significant effect on OPG or RANKL in this model.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0955-2863
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
54-63
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Effects of arachidonic acid, docosahexaenoic acid, prostaglandin E(2) and parathyroid hormone on osteoprotegerin and RANKL secretion by MC3T3-E1 osteoblast-like cells.
pubmed:affiliation
Department of Physiology, University of Pretoria, PO Box 2034, Pretoria 0001, South Africa. magdalena.coetzee@up.ac.za
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't