title: Cytosolic phospholipase A2 and eicosanoids modulate life, death and function of human osteoclasts in vitro.
abstract: BACKGROUND
  Eicosanoids are important in bone physiology but the specific function of phopholipase enzymes has not been determined in osteoclasts. The objective of this is study was to determine the presence of cPLA2 in human in vitro-differentiated osteoclasts as well as osteoclasts in situ from bone biopsies.
  
  
  METHODS
  Osteoclastogenesis, apoptosis, bone resorption and the modulation of actin cytoskeleton assays were performed on osteoclasts differentiated in vitro. Immunohistochemistry was done in differentiated osteoclasts as well as on bone biopsies.
  
  
  RESULTS
  Human osteoclasts from normal, fetal, osteoarthritic, osteoporotic and Pagetic bone biopsies express cPLA2 and stimulation with RANKL increases cPLA2 phosphorylation in vitro. Inhibition of cPLA2 increased osteoclastogenesis and decreased apoptosis but decreased the capacity of osteoclasts to generate actin rings and to resorb bone.
  
  
  CONCLUSIONS
  These results suggest that cPLA2 modulates osteoclast functions and could be a useful target in bone diseases with hyperactivated osteoclasts.
authors: Division of Rheumatology, Faculté de médecine et des sciences de la santé de l' Université de Sherbrooke et Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Québec, Canada. Electronic address: hugues.allard-chamard@usherbrooke.ca.
authors: Hugues
authors: H
authors: Allard-Chamard
authors: Division of Rheumatology, Faculté de médecine et des sciences de la santé de l' Université de Sherbrooke et Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Québec, Canada. Electronic address: philippe.dufort@usherbrooke.ca.
authors: Philippe
authors: P
authors: Dufort
authors: Division of Rheumatology, Faculté de médecine et des sciences de la santé de l' Université de Sherbrooke et Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Québec, Canada. Electronic address: sonia.haroun@usherbrooke.ca.
authors: Sonia
authors: S
authors: Haroun
authors: Division of Rheumatology, Faculté de médecine et des sciences de la santé de l' Université de Sherbrooke et Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Québec, Canada. Electronic address: artur.fernandes@usherbrooke.ca.
authors: Artur J
authors: AJ
authors: de Brum-Fernandes
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D017209:Apoptosis; D001862:Bone Resorption / Q000201:enzymology; D001842:Bone and Bones / Q000201:enzymology / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D015777:Eicosanoids / Q000502:physiology*; D006801:Humans; D010003:Osteoarthritis / Q000201:enzymology; D010010:Osteoclasts / Q000201:enzymology* / Q000502:physiology; D010024:Osteoporosis / Q000201:enzymology; D054510:Phospholipases A2, Cytosolic / Q000502:physiology*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational
chemical_list: D015777:Eicosanoids; D054510:Phospholipases A2, Cytosolic
keywords: Bone; Eicosanoids; Osteoclasts; Phospholipases; Prostaglandins