Study of osteoclast activating factor when mechanical stress changes through osteoblast controlled by osteocyte

• Project/Area Number: 20791047
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Orthopaedic surgery
• Research Institution: Nagasaki University
• Principal Investigator: (MORIISHI Takeshi Nagasaki University, 大学院・医歯薬学総合研究科, 技術職員 (20380983)
• Project Period (FY): 2008 – 2009
• Project Status: Completed (Fiscal Year 2009)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2009: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2008: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
• Keywords: 力学的負荷 / 骨細胞 / 骨芽細胞 / 破骨細胞活性化因子 / RANKL / 破骨細胞誘導 / Bcl-2 / Bc1-2

Research Abstract

We established human Bcl-2 transgenic mice under the control of mouse 2.3 kb Col1a1 promoter. Osteocyte processes were reduced depending on the expression levels of the transgene and they were sparsely connected with each other in Bcl-2 transgenic mice. At the unloaded condition, bone mass decreased in wild-type mice due to impaired osteoblast function and enhanced osteoclastogenesis through RANKL induction but not in Bcl-2 transgenic mice. These findings show that osteocytes negatively regulate bone mass by inhibiting osteoblast function and activating osteoclastogenesis and these functions are augmented at the unloaded condition. Moreover, osteocyte expression gene analysis using microarray showed that 5322 genes are chang in Runx2 transgenic mice (Dev Biol. 2006 Aug 1 ; 296 (1) : 48-61), at unloaded condition. Our findings will provide the basis for the understanding of the osteocyte network, which plays an important role in the regulation of bone mass.

Research Products

• [Journal Article] Ultrastructural analysis of osteoblasts, osteocytes and odontoblasts in Runx2 transgenic mice. (2009)
  • Author(s): Miyazaki, T, Moriishi, T, Izumi, S, Baba, T, Komori, T
  • Journal Title: 6th international Symposium on Electron Microscopy in Medicine and Biology, Kobe, Japan Pages: 67-67
• [Journal Article] Ultrastructural analysis of osteoblasts, osteocytes and odontoblasts in Runx2 transgenic mice. (2009)
  • Author(s): Miyazaki, T, Moriishi, T, Izumi, S, Baba, T, Komori, T
  • Journal Title: 6th international Symposium on Electron Microscopy in Medicine and Biology Pages: 67-67
• [Presentation] 骨芽細胞特異的Bc1-2過剰発現マウスでは骨芽細胞の分化抑制と骨細胞死が起こる (2009)
  • Author(s): 森石武史、宮崎敏博、和泉伸一、小守壽文
  • Organizer: 第51回歯科基礎医学会
  • Place of Presentation: 新潟
  • Year and Date: 2009-09-11
• [Presentation] 骨芽細胞特異的Bcl-2過剰発現マウスでは骨芽細胞の分化抑制と骨細胞死が起こる森石武史 (2009)
  • Author(s): 宮崎敏博、和泉伸一、小守壽文
  • Organizer: 第51回歯科基礎医学会
  • Place of Presentation: 新潟
• [Presentation] Ultrastructural analysis of osteoblasts, osteocytes and odontoblasts in Runx2 transgenic mice. (2009)
  • Author(s): Miyazaki T, Moriishi T, Izumi S, Baba T, Komori T
  • Organizer: 6th international Symposium on Electron Microscopy in Medicine and Biology
  • Place of Presentation: Kobe, Japan