Summary of Research Project Results under JSPS FY2004
"Research for the Future Program"

1. Research Institution   National Institutes of Natural Sciences
2. Research Area Life Sciences
3. Research Field Development, Differentiation, and Regeneration
4. Term of Project FY 2000 - FY 2004
5. Project Number 00L01507
6. Title of Project Studies on Molecular Mechanisms Underlying Development, Differentiation and Regeneration of Neural Cells

7. Project Leader

Name Institution, Department Title of Position
Kazuhiro, Ikenaka National Institutes of Natural Sciences,National Institutes for Physiological Sciences Professor

8. Core Members

Names Institution, Department Title of Position
Takahiro, Hirabayashi National Institutes of Natural Sciences,National Institutes for Physiological Sciences Assistant Professor
Hideki, Hida Nagoya City University, Graduate School of Medical Sciences Associate Professor

9. Summary of Research Results

  1. Motoneurons and oligodendrocytes (OLs) are produced from a restricted domain, called the pMN domain, in the embryonic spinal cord. Two basic helix-loop-helix transcription factors, Olig1 and Olig2, which are essential for motoneuron and OL development, are expressed in this region. However, the final cell fate of neuroepithelial cells in the pMN domain was not clear. Lineage-tracing experiments using tamoxifen-inducible Cre-recombinase inserted into the Olig2 locus indicated that astrocytes and ependymal cells are also produced from the pMN domain.
  2. Sonic hedgehog had been identified as an essential ventral factor for OL lineage specification, whereas the dorsal cue was less clear. In this study, Wnt proteins were identified as dorsal factors that directly inhibit OL development. Wnt signaling through a canonical -catenin pathway prevents its differentiation from progenitor to an immature state.
  3. Differentiation factors related to DAergic differentiation from neural stem cells (NSCs) were investigated. Expression of pleiotrophin (PTN) was enhanced in DA-depleted striatum, and frequently found in ventral mesencephalon-derived neurospheres. Treatment of ES-derived NSCs with PTN increased the number of TH-positive neurons after DAergic differentiation, treatment of cultured DAergic neurons promoted the survival and PTN treatment of the donor cells during cell preparation induced the recovery of disturbed motor function after transplantation to hemi-parkinson model rats.
  4. All attempts to produce live cloned offspring using the nuclei of neurons from adult cerebral cortex have failed. We found that the nuclei of neural cells in advanced stages of differentiation had lost their developmental totipotency. Although we were unable to obtain live cloned pups, many fetuses reached day 10.5 days of development. The conventional nuclear transfer technique does not allow nuclei of differentiated neurons to undergo complete genomic reprogramming required for normal embryonic development. However, cloned adult mice were obtained with nuclei from ES cell lines established by cloned embryos using differentiated neurons.

10. Key Words

( 1 ) Wnt signaling ( 2 ) oligodendrocyte ( 3 ) myelin
( 4 ) ES-derived neural stem cells ( 5 ) Pleiotrophin ( 6 ) Cell cycle regulation
( 7 ) Neuron ( 8 ) mouse cloning ( 9 ) nuclear information