Living in Space
Integral Understanding of life-regulation mechanism from "SPACE"

Role of osteocyte PI3K in regulation of bone homeostasis – Publicly Invited Research 2018－2019

1. A01 Ogura
2. A01 H. Takahashi
3. A01 S. Takahashi
4. A01 Michiue
5. A01 Hinoi
6. A01 Tsumoto
7. A01 Nikawa
8. A01 Chatani
9. A01 Kawakami
10. A01 Akiyama
11. A01 Tomita

1. A02 Shinohara
2. A02 Mieda
3. A02 Maekawa
4. A02 Abe
5. A02 Ohgami
6. A02 Kawano
7. A02 Takano

1. A03 Suzuki
2. A03 Nakamura
3. A03 Harada
4. A03 Kobayashi
5. A03 Miyamoto
6. A03 Funayama
7. A03 Kakinuma

1. B01 Lazarus
2. B01 Kato
3. B01 Kunieda
4. B01 Kitaya
5. B01 Sawano

Research Subject	Role of osteocyte PI3K in regulation of bone homeostasis
Research Group Leader	Masahiro Shinohara Section Chief, Molecular Pathophysiology Section, Department of Rehabilitation for the Movement Functions, Research Institute National Rehabilitation Center for Persons with Disabilities Website http://
Research Collaborator(s)	Hironobu Morita Professor, School of Medicine, Gifu University Satoru Takahashi Professor, School of Medicine and Medical Sciences, University of Tsukuba Dai Shiba Associate Senior Engineer, JAXA Yasuhiro Sawada Director, Research Institute, National Rehabilitation Center for Persons with Disabilities

Mechanical loading is a critical factor for maintaining bone tissue homeostasis. Bone-embedded cells, osteocytes are primarily responsible to the mechanical loading in the bone tissue, and have critical roles in the regulating bone-forming osteoblasts and bone-resorbing osteoclasts. Under mechanical unloading conditions such as microgravity during the spaceflight, both bone mass and strength decrease due to enhanced osteoclastic bone resorption and suppressed osteoblastic bone formation, leading to osteoporosis, a bone disease with a high risk of bone fracture.

In this project, we reveal the molecular mechanism(s) by which osteocytes sense the mechanical loading and regulate bone homeostasis by focusing a signal transduction molecule PI3K in osteocytes.