title: PI3Kγ deletion reduces variability in the in vivo osteolytic response induced by orthopaedic wear particles.
abstract: Orthopedic wear particles activate a number of intracellular signaling pathways associated with inflammation in macrophages and we have previously shown that the phosphoinositol-3-kinase (PI3K)/Akt pathway is one of the signal transduction pathways that mediates the in vitro activation of macrophages by orthopedic wear particles. Since PI3Kγ is primarily responsible for PI3K activity during inflammation, we hypothesized that PI3Kγ mediates particle-induced osteolysis in vivo. Our results do not strongly support the hypothesis that PI3Kγ regulates the overall amount of particle-induced osteolysis in the murine calvarial model. However, our results strongly support the conclusion that variability in the amount of particle-induced osteolysis between individual mice is reduced in the PI3Kγ(-/-) mice. These results suggest that PI3Kγ contributes to osteolysis to different degrees in individual mice and that the mice, and patients, that are most susceptible to osteolysis may be so, in part, due to an increased contribution from PI3Kγ.
authors.affiliation: Department of Orthopaedics, Case Western Reserve University, University Hospitals Case Medical Center, Biomedical Research Building, Room 331, 2109 Adelbert Road, Cleveland, Ohio 44106, USA. emg3@cwru.edu
authors.forename: Edward M
authors.initials: EM
authors.lastname: Greenfield
authors.forename: Joscelyn M
authors.initials: JM
authors.lastname: Tatro
authors.forename: Matthew V
authors.initials: MV
authors.lastname: Smith
authors.forename: Erik A
authors.initials: EA
authors.lastname: Schnaser
authors.forename: Dianqing
authors.initials: D
authors.lastname: Wu
mesh_terms: D000818:Animals; D058544:Class Ib Phosphatidylinositol 3-Kinase / Q000235:genetics* / Q000378:metabolism; D005260:Female; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D010000:Osteitis / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D010014:Osteolysis / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D010294:Parietal Bone / Q000276:immunology / Q000473:pathology; D020959:Polyethylene / Q000009:adverse effects; D011475:Prosthesis Failure; D015398:Signal Transduction / Q000502:physiology; D014025:Titanium / Q000009:adverse effects
chemical_list: D020959:Polyethylene; D014025:Titanium; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546764:Pik3cg protein, mouse