title: Protein kinase D promotes in vitro osteoclast differentiation and fusion.
abstract: Although PKD is broadly expressed and involved in numerous cellular processes, its function in osteoclasts has not been previously reported. In this study, we found that PKD2 is the main PKD isoform expressed in osteoclastic cells. PKD phosphorylation, indicative of the activated state, increased after 2-3 days of treatment of bone marrow macrophages with M-CSF and RANKL, corresponding to the onset of preosteoclast fusion. RNAi against PKD2 and treatment with the PKD inhibitor CID755673 showed that PKD activity is dispensable for induction of bone marrow macrophages into tartrate-resistant acid phosphatase-positive preosteoclasts in culture but is required for the transition from mononucleated preosteoclasts to multinucleated osteoclasts. Loss of PKD activity reduced expression of DC-STAMP in RANKL-stimulated cultures. Overexpression of DC-STAMP was sufficient to rescue treatment with CID755673 and restore fusion into multinucleated osteoclasts. From these data, we conclude that PKD activity promotes differentiation of osteoclast progenitors through increased expression of DC-STAMP.
authors: Department of Developmental and Surgical Sciences, University of Minnesota, Minneapolis, Minnesota 55455.
authors: Kim C
authors: KC
authors: Mansky
authors: Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, Minnesota 55455. Electronic address: jens0709@umn.edu.
authors: Eric D
authors: ED
authors: Jensen
authors: Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455.
authors: Julia
authors: J
authors: Davidova
authors: Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455.
authors: Masato
authors: M
authors: Yamamoto
authors: Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, Minnesota 55455. Electronic address: gopal007@umn.edu.
authors: Rajaram
authors: R
authors: Gopalakrishnan
mesh_terms: D000818:Animals; D017209:Apoptosis; D001381:Azepines / Q000494:pharmacology; D001572:Benzofurans / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology; D001862:Bone Resorption; D001842:Bone and Bones / Q000378:metabolism; D002454:Cell Differentiation; D015971:Gene Expression Regulation, Enzymologic; D066298:In Vitro Techniques; D016086:Lentivirus / Q000235:genetics; D008264:Macrophages / Q000166:cytology; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D053245:RANK Ligand / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D001381:Azepines; D001572:Benzofurans; C534615:CID755673; C499636:DC-STAMP protein, mouse; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D053245:RANK Ligand; C089212:protein kinase D; D011493:Protein Kinase C