title: Phosphodiesterase 3 and 4 negatively regulate receptor activator of nuclear factor-kappaB ligand-mediated osteoclast formation by prostaglandin E2.
abstract: Prostaglandin E2 (PGE2) stimulates osteoclast formation by increasing receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) mRNA expression via cAMP-protein kinase A (PKA) pathways in osteoblasts. Since phosphodiesterases (PDEs) balance the concentration of intracellular cAMP stimulated by PGE2, we investigated the role of PDEs in PGE2-mediated osteoclast formation using various cAMP-specific PDEs inhibitors. In the presence of PGE(2), PDE3 and 4 inhibitors were shown to dose-dependently increase the osteoclast formation in cocultures of mouse bone marrow cells and calvarial osteoblasts. In agreement with this finding, they stimulated PGE2-induced cAMP production followed by increased RANKL mRNA expression in osteoblasts, suggesting that PDE3 and 4 negatively regulate PGE2-mediated RANKL expression in osteoblasts. RT-PCR analysis revealed that PDE3A, 3B, 4A, 4B and 4D are expressed in osteoblasts. The PDE8 inhibitor did not increase osteoclast formation, although it stimulated PGE2-induced RANKL mRNA expression in osteoblasts. The four subtypes of PGE receptors are designated EP1, EP2, EP3, and EP4. PDE3 and 4 inhibitors were found to increase EP1/3, EP4 and/or EP2 agonist-stimulated RANKL expression, indicating that PDE3 and PDE4 negatively regulate PGE2-induced RANKL mRNA expression through four EPs. Taken together, these data suggest that PDE3 and PDE4 could have important pharmacological and clinical implications in bone-related diseases.
authors.affiliation: College of Pharmacy, Sookmyung Women's University, Hyochangwongil 52, Yongsan-ku, Seoul 140-742, Republic ofKorea.
authors.forename: A Long Sae Mi
authors.initials: AL
authors.lastname: Noh
authors.forename: Mihye
authors.initials: M
authors.lastname: Yang
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Hyojung
authors.initials: H
authors.lastname: Park
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Lee
authors.forename: Mijung
authors.initials: M
authors.lastname: Yim
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3 / Q000378:metabolism*; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000378:metabolism*; D015232:Dinoprostone / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D051379:Mice; D010010:Osteoclasts / Q000166:cytology*; D053245:RANK Ligand / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D053245:RANK Ligand; D012333:RNA, Messenger; C505689:Tnfsf11 protein, mouse; D048051:p38 Mitogen-Activated Protein Kinases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D015232:Dinoprostone