title: PTH-Induced Osteoblast Proliferation Requires Upregulation of the Ubiquitin-Specific Peptidase 2 (Usp2) Expression.
abstract: Osteoporosis is a common disease that increases individual's fragility fracture risk. PTH is the only therapeutic agent for severe osteoporosis that requires anabolic action of bone formation. Although a part of the PTH actions is explained by increased proliferation of osteoblastic precursor cells, the mechanisms involved in the proliferation of osteoblastic cells by PTH have not been clarified yet. Therefore, in this study, we investigated the effects of PTH on gene expression in the cultured osteoblastic MC3T3-E1 cells, and found that the ubiquitin-specific peptidase 2 (Usp2) may be one of the direct target genes of PTHR signaling. Usp2 is a deubiquitination enzyme targeting various factors including CyclinD1 in cancer cells and PTH receptor 1 in osteoblasts. We confirmed that consistent induction of Usp2 expression peaked at 1 h by PTH1-34 (teriparatide) in MC3T3-E1 cells and primary calvarial osteoblasts. Among the three known splicing variants of the Usp2, we found the isoforms 1 and 2 are predominantly expressed in osteoblasts. Live-imaging analysis of the Fucci-transgenic mouse-derived primary osteoblasts indeed demonstrated that Usp2 is required for the PTH1-34-induced osteoblast proliferation. Western blotting analysis of the CyclinD1 indicated that Usp2 knock-down influences the paradoxical changes of CyclinD1 protein levels in this condition. Our data indicate that Usp2 is required for the PTH1-34-induced proliferation of osteoblasts.
authors.affiliation: Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8510, Japan.|Global COE Program, Tokyo Medical and Dental University, Tokyo, Japan.|Department of Oral and Maxillofacial Surgery, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Jumpei
authors.initials: J
authors.lastname: Shirakawa
authors.affiliation: Department of Oral and Maxillofacial Surgery, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Harada
authors.affiliation: Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8510, Japan. noda.mph@mri.tmd.ac.jp.|Global COE Program, Tokyo Medical and Dental University, Tokyo, Japan. noda.mph@mri.tmd.ac.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Noda
authors.affiliation: Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8510, Japan. ezura.mph@mri.tmd.ac.jp.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ezura
mesh_terms: D016475:3T3 Cells; D017398:Alternative Splicing; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D049109:Cell Proliferation; D019938:Cyclin D1 / Q000378:metabolism; D005786:Gene Expression Regulation; D051379:Mice; D008822:Mice, Transgenic; D010006:Osteoblasts / Q000166:cytology*; D010281:Parathyroid Hormone / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D043222:Ubiquitin Thiolesterase; D064570:Ubiquitin-Specific Proteases / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C530105:Ccnd1 protein, mouse; D010281:Parathyroid Hormone; D034741:RNA, Small Interfering; D019938:Cyclin D1; D043222:Ubiquitin Thiolesterase; D064570:Ubiquitin-Specific Proteases; C579224:Usp2 protein, mouse
keywords: Osteoblast; PTH; Proliferation; Usp2