[Frontiers in Bioscience 16, 1044-1059, January 1, 2011]

The spinal cord ependymal region: A stem cell niche in the caudal central nervous system

Jean Philippe Hugnot1, 2, Rachelle Franzen3

1INSERM U583, Physiopathologie et Therapie des deficits sensoriels et moteurs, Institut des Neurosciences de Montpellier, Hopital St ELOI, BP 74103 80, av Augustin Fliche 34091 Montpellier Cedex 05, France, 2Universite Montpellier 2, Place Eugene Bataillon, 34095 Montpellier, 3GIGA Neurosciences, Unite de recherches sur la regeneration axonale et la douleur cephalique, Universite de Liege, Tour de Pathologie B36/+1, Avenue de l'Hopital, 4000 Liege, Belgique

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Cellular composition of the ependymal region in mammals 3.1. Ependymocytes-Tanycytes
3.2. Cerebral-fluid contacting neurons (CSF-cNs)
3.3. Supra-ependymal cells
3.4. Human ependyma
4. Embryonic origin and post natal development of the ependyma
4.1. Embryonic development
4.2. Post-natal development 5. Stem cells in the ependymal region
6. Ependyma and spinal cord injury and diseases
6.1. Spinal cord injury
6.2. Amyotrophic lateral sclerosis
6.3. Multiple sclerosis
7. Online databases for characterisation of the spinal cord niche
8. Conclusion
9. Acknowledgements 10. References

1. ABSTRACT

In the brain, specific signalling pathways localized in highly organized regions called niches, allow the persistence of a pool of stem and progenitor cells that generate new neurons and glial cells in adulthood. Much less is known on the spinal cord central canal niche where a sustained adult neurogenesis is not observed. Here we review our current knowledge of this caudal niche in normal and pathological situations. Far from being a simple layer of homogenous cells, this region is composed of several cell types localized at specific locations, expressing characteristic markers and with different morphologies and functions. We further report on a screen of online gene-expression databases to better define this spinal cord niche. Several genes were found to be preferentially expressed within or around the central canal region (Bmp6, CXCR4, Gdf10, Fzd3, Mdk, Nrtn, Rbp1, Shh, Sox4, Wnt7a) some of which by specific cellular subtypes. In depth characterization of the spinal cord niche constitutes a framework to make the most out of this endogenous cell pool in spinal cord disorders.