2019 Fiscal Year Research-status Report
Elucidation of the molecular mechanisms for the impaired bone formation in disuse osteoporosis and GC-induced osteoporosis using Fkbp5 knockout mice
| Project/Area Number |
19K24124
|
|---|
| Research Institution | Nagasaki University |
|---|
Principal Investigator |
QIN XIN 長崎大学, 医歯薬学総合研究科(歯学系), 特任研究員 (60846559)
|
|---|
| Project Period (FY) |
2019-08-30 – 2021-03-31
|
| Keywords | osteoporosis / bone development |
|---|
| Outline of Annual Research Achievements |
Fkbp5 (FK506 binding protein 51) binds to glucocorticoid receptor (GR) and inhibits the nuclear translocation of GR. We identified Fkbp5 as an unloading-induced molecule in osteoblasts and osteocytes. We generated Fkbp5 knockout mice, but they showed normal development of bone and normal bone volume in adults. Bone loss occurred more severely in Fkbp5 knockout mice than wild-type mice at unloading condition and with glucocorticoid (GC) treatment. The main purpose of this study is to elucidate the molecular mechanism of impaired bone formation in disuse osteoporosis and GC-induced osteoporosis by comparing gene expression between physiological and unloaded groups and between control and GC treatment groups using wild-type and Fkbp5 knockout osteoblasts and osteocytes.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
To clarify the molecular mechanism for impaired bone formation in disuse and GC-induced osteoporosis, we performed microarray analysis by using osteoblast and osteocyte fractions to identify the differentially expressed genes among wild-type and Fkbp5 knockout mice with or without tail suspension and with or without GC treatment. The expression of the selected genes by gene annotation and pathway analyses were analyzed by real-time reverse transcription (RT)-PCR.
To investigate the relationship of GR, Fkbp5 and Runx2, we performed immunocytochemistry using GR and Runx2 antibodies to observe their localization in wild-type and Fkbp5 knockout primary osteoblasts with or without Dex treatment. Further, we performed co-IP to examine the binding of GR and Runx2 with or without Dex treatment.
|
| Strategy for Future Research Activity |
We will generate knockout mice of the finally selected genes, and the phenotypes of the mice with or without tail suspension and with or without GC treatment will be analyzed by histological and micro-CT analyses. The differentiation and functions of osteoblasts will be examined by in situ hybridization, real-time RT-PCR, and Western blot analyses of osteoblast marker genes and proteins. A loxP inserted mouse will also be established if necessary, and we will use 2.3 kb Col1a1 promoter GFP-Cre transgenic mice, which we established, to generate osteoblast-specific knockout mice. By combining the results obtained by above experiments, we will publish molecular mechanism for impaired bone formation in disuse and GC-induced osteoporosis will be clarified.
|
| Causes of Carryover |
理由 We already finished microarray analysis and identify the differentially expressed genes among wild-type and Fkbp5 knockout mice with or without tail suspension and with or without GC treatment, we need to generate knockout mice and perform general bone analyses.
使用計画We will generate knockout mice of the finally selected genes, and the phenotypes of the mice with or without tail suspension and with or without GC treatment will be analyzed by histological and micro-CT analyses.
|
