HDL3 reduces the association and modulates the metabolism of oxidized LDL by osteoblastic cells: A protection against cell death

Oxidized low density lipoproteins (OxLDL) are known to promote atherosclerosis, but it is only recently that OxLDL have been associated with alterations of the functions of bone‐forming osteoblasts and osteoporosis. Although high density lipoproteins (HDL) are recognized for their anti‐atherogenic a...

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Bibliographic Details
Published in:Journal of cellular biochemistry 2008-12, Vol.105 (6), p.1374-1385
Main Authors: Brodeur, Mathieu R., Brissette, Louise, Falstrault, Louise, Moreau, Robert
Format: Article
Language:English
Subjects:
cell death
Cell Death - physiology
Cells, Cultured
cholesterol
efflux
high density lipoprotein
Humans
Lipoproteins, HDL3 - metabolism
Lipoproteins, LDL - metabolism
Lipoproteins, LDL - pharmacology
low density lipoprotein
osteoblast
Osteoblasts - metabolism
OxLDL
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Summary:Oxidized low density lipoproteins (OxLDL) are known to promote atherosclerosis, but it is only recently that OxLDL have been associated with alterations of the functions of bone‐forming osteoblasts and osteoporosis. Although high density lipoproteins (HDL) are recognized for their anti‐atherogenic action, there is less information about their ability to protect against osteoporosis. Therefore, we investigated the capacity of HDL3 to prevent the cell death induced by OxLDL in human osteoblastic cells. Simultaneous exposure of the cells to HDL3 and OxLDL abolished the reduction of cell viability monitored by MTT activity measurement and the induction of apoptosis determined by annexin V staining indicating that HDL3 prevent the apoptosis of osteoblasts induced by OxLDL. This protection correlated with the displacement by HDL3 of OxLDL association to osteoblasts, signifying that OxLDL binding and/or internalization are/is necessary for their cytotoxic effects. We also found that exposition of osteoblastic cells to HDL3 prior to incubation with OxLDL reduced cell death and preserved the lysosomal integrity. This protection was correlated with an increase of SR‐BI expression, a modification of OxLDL metabolism with less global uptake of OxLDL and greater selective uptake of cholesterol from OxLDL. These results strongly suggest that, as for atherosclerosis, HDL may exert beneficial actions on bone metabolism. J. Cell. Biochem. 105: 1374–1385, 2008. © 2008 Wiley‐Liss, Inc.
ISSN:0730-2312
1097-4644
DOI:10.1002/jcb.21938