2017 Fiscal Year Annual Research Report
The investigation of Vitamin D system on muscle
| Project/Area Number |
16K19555
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| Research Institution | National Center of Neurology and Psychiatry |
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Principal Investigator |
MARIA TSOUMPRA 国立研究開発法人国立精神・神経医療研究センター, 神経研究所 遺伝子疾患治療研究部, 科研費研究員 (80756198)
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| Project Period (FY) |
2016-04-01 – 2018-03-31
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| Keywords | Vitamin D / Vitamin D receptor / Biglycan |
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| Outline of Annual Research Achievements |
I have generated muscle specific VDR knockout mice by crossing Mlc1f-cre with VDR-floxed mice and observed reduced four limb grip power in homozygote males at 6th and 8th week. I employed microarray studies to identify candidate genes that could exert a VDR direct effect on muscle. One of my targets, biglycan (Bgn), a component of DAPC, was increased in tibialis anterior of 5 wk homozygotes. I then demonstrated that Bgn was dose-dependently downregulated upon daily administration of VD3 on day six of C2C12 myogenic differentiation. Treatment of C2C12 cells with VD3 on days 1-3 and 4-6 suppressed Bgn, utrophin (Utrn) and syntrophin basic 1 (Sntb1) but increased dystrobrevin alpha-1 (Dtna1) levels. Furthermore Dtna1 -silenced myocytes exhibit less myogenin compared to the scrambled transfected ones indicating possible modulation of myogenin through Dtna1. I cloned various lengths of Dtna1 promoter in pGL4 luciferase promoterless vector containing different numbers of in silico identified VDRE. Luciferase activity was dose-dependently increased according to the amount of VD3 used and was dependent on the number of VDRE included in the construct. There was no VD3 specific induction when no VDRE was included. I have induced muscle regeneration in my homozygote and control group by BaCl2 injection into TA muscle. At day 4 post-injection, I observed blunted Bgn, Utrn and Dtna1 gene induction in the VDRKO versus the control. I therefore demonstrated that these two genes are targets of VD3/VDR and in the future I will reveal their significance in muscle physiology.
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