title: Influence of oxidized low-density lipoproteins (LDL) on the viability of osteoblastic cells.
abstract: Cardiovascular diseases have recently been noted as potential risk factors for osteoporosis development. Although it is poorly understood how these two pathologies are related, it is a known fact that oxidized low-density lipoproteins (OxLDL) constitute potential determinants for both of them. The current study investigated the metabolism of OxLDL by osteoblasts and its effect on osteoblastic viability. The results obtained show that OxLDL are internalized but not degraded by osteoblasts while they can selectively transfer their CE to these cells. It is also demonstrated that OxLDL induce proliferation at low concentrations but cell death at high concentrations. This reduction of osteoblast viability was associated with lysosomal membrane damage caused by OxLDL as demonstrated by acridine orange relocalization. Accordingly, chloroquine, an inhibitor of lysosomal activity, accentuated cell death induced by OxLDL. Finally, we demonstrate that osteoblasts have the capacity to oxidize LDL and thereby potentially increase the local concentration of OxLDL. Overall, the current study confirms the potential role of OxLDL in the development of osteoporosis given its influence on osteoblastic viability.
authors.affiliation: Département des Sciences Biologiques, Université du Québec à Montréal, CP 8888, succ Centre-Ville, Montreal (Quebec), Canada H3C 3P8.
authors.forename: Mathieu R
authors.initials: MR
authors.lastname: Brodeur
authors.forename: Louise
authors.initials: L
authors.lastname: Brissette
authors.forename: Louise
authors.initials: L
authors.lastname: Falstrault
authors.forename: Pascale
authors.initials: P
authors.lastname: Ouellet
authors.forename: Robert
authors.initials: R
authors.lastname: Moreau
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity*; D008247:Lysosomes / Q000187:drug effects; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D010024:Osteoporosis / Q000209:etiology*; D010084:Oxidation-Reduction; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism
chemical_list: D008077:Lipoproteins, LDL; D013778:Tetrazolium Salts; D013844:Thiazoles; C099252:oxidized low density lipoprotein; C022616:thiazolyl blue