title: Administration of cyclooxygenase-2 inhibitor reduces joint inflammation but exacerbates osteopenia in IL-1 alpha transgenic mice due to GM-CSF overproduction.
abstract: IL-1alpha transgenic (Tg) mice exhibit chronic inflammatory arthritis and subsequent osteopenia, with IL-1-induced GM-CSF playing an important role in the pathogenesis. This study analyzed the mechanisms underlying osteopenia in Tg mice, and the therapeutic effects of the cyclooxygenase-2 inhibitor celecoxib on such osteopenia. Inhibited osteoclast formation was observed in RANKL-treated bone marrow cell (BMC) cultures from Tg mice and coculture of Tg-derived BMCs and wild-type-derived primary osteoblasts (POBs). FACS analysis indicated that this inhibition was attributable to a decreased number of osteoclast precursors within Tg-derived BMCs. Moreover, in coculture of Tg-derived POBs and either Tg- or wild-type-derived BMCs, osteoclast formation was markedly inhibited because Tg-derived POBs produced abundant GM-CSF, known as a potent inhibitor of osteoclast differentiation. Histomorphometric analysis of Tg mice revealed that both bone formation and resorption were decreased, with bone formation decreased more prominently. Interestingly, administration of celecoxib resulted in further deterioration of osteopenia where bone formation was markedly suppressed, whereas bone resorption remained unchanged. These results were explained by our in vitro observation that celecoxib dose-dependently and dramatically decreased osteogenesis by Tg mouse-derived POBs in culture, whereas mRNA expressions of GM-CSF and M-CSF remained unchanged. Consequently, blockade of PGE(2) may exert positive effects on excessively enhanced bone resorption observed in inflammatory bone disease, whereas negative effects may occur mainly through reduced bone formation, when bone resorption is constitutively down-regulated as seen in Tg mice.
authors.affiliation: Department of Orthopaedic Surgery, Keio University, Tokyo, Japan. y-niki@lib.bekkoame.ne.jp
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Niki
authors.forename: Hironari
authors.initials: H
authors.lastname: Takaishi
authors.forename: Jiro
authors.initials: J
authors.lastname: Takito
authors.forename: Takeshi
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Naoto
authors.initials: N
authors.lastname: Kosaki
authors.forename: Hideo
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Norihiro
authors.initials: N
authors.lastname: Tada
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage; D001169:Arthritis, Experimental / Q000201:enzymology / Q000235:genetics* / Q000276:immunology / Q000517:prevention & control*; D001851:Bone Diseases, Metabolic / Q000201:enzymology / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D001862:Bone Resorption / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000517:prevention & control; D000068579:Celecoxib; D002478:Cells, Cultured; D018920:Coculture Techniques; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage*; D015232:Dinoprostone / Q000037:antagonists & inhibitors*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics; D053582:Interleukin-1alpha / Q000235:genetics*; D051379:Mice; D008809:Mice, Inbred C3H; D008822:Mice, Transgenic; D010010:Osteoclasts / Q000201:enzymology / Q000473:pathology; D010012:Osteogenesis / Q000235:genetics; D011720:Pyrazoles / Q000008:administration & dosage; D013449:Sulfonamides / Q000008:administration & dosage
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors; D053582:Interleukin-1alpha; D011720:Pyrazoles; D013449:Sulfonamides; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D000068579:Celecoxib; D015232:Dinoprostone