2007 Fiscal Year Final Research Report Summary
Investigation of the mechanism of osteogenic induction by clock genes
| Project/Area Number |
18592261
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Periodontal dentistry
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| Research Institution | Hiroshima University |
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Principal Investigator |
FUJIOKA Daisuke Hiroshima University, Hospital, Assistant Professor (20379879)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHINO Hiroshi Hiroshima University, Hospital, Associate Professor (50240338)
FUJITA Tsuyoshi Hiroshima University, Hospital, Assistant Professor (80379883)
MIZUNO Noriyoshi Hiroshima University, Graduate school of Biomedical Sciences, Assistant Professor (60325181)
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| Project Period (FY) |
2006 – 2007
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| Keywords | clock genes / hypoxia / mesenchymal stem cell / osteogenesis / DEC1 / HIF-1α |
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| Research Abstract |
The purpose of this study is to investigate the osteogenic mechanism induced by DEC1, a kind of clock genes, of mesenchymal stem cells (MSC). For this purpose, the following experiments have been performed.
(1) The effects of clock genes on osteogenesis of MSC By DEC1 overexpression, Runx2 and Osterix mRNA expression were increased. Moreover, alkaline phosphatase (ALPase) activity and bone matrix calcification were also enhanced.
(2) The alteration in osteogenesis related genes expression affected by inducers of clock genes
(1) By hypoxic condition, DEC1 mRNA expression increased. Furthermore, Runx2 and Osterix mRNA were up-regulated, and Osteopontin (OP), ALPase, Osteocalcin (OC) mRNA were down-regulated.
By re-oxygenation after the culture under hypoxic condition, OP, ALPase, Runx2 and Osterix mRNA expression were elevated in osteogenic induction
(3) Investigation of the mechanism for induction of osteogenesis-related gene induced by clock genes.
To reveal this mechanism, we investigated the effect of HIF-1α induced by hypoxic condition.
(1) By HIF-1α overexpression with plasmid DNA, mRNA expression of DEC1 and osteogenesis related genes did not change
(2) By the suppression of HIF-1α mRNA expression with siRNA, Osterix mRNA expression was decreased.
(3) By enhancement of HIF-1α transcriptional activity with histone deacetylase (HDAC) inhibitor, DEC1 mRNA was induced, OP mRNA was up-regulated and OC mRNA was down-regulated.
In conclusion, DEC1, one of clock genes, can be controlled by HIF-1α which induced by hypoxic condition, and it is indicated that DEC1 can influence osteogenesis of MSC via the adjustments of HIF-1α expression and transcriptional activity under hypoxic condition. Therefore, on the osteogenesis regulated by DEC1, it is suggested that HIF- 1α can play an important role on the osteogenesis.
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