Increased Dentate Neurogenesis After Grafting of Glial Restricted Progenitors or Neural Stem Cells in the Aging Hippocampus
Article first published online: 17 MAY 2007
Copyright © 2007 AlphaMed Press
Volume 25, Issue 8, pages 2104–2117, August 2007
How to Cite
Hattiangady, B., Shuai, B., Cai, J., Coksaygan, T., Rao, M. S. and Shetty, A. K. (2007), Increased Dentate Neurogenesis After Grafting of Glial Restricted Progenitors or Neural Stem Cells in the Aging Hippocampus. STEM CELLS, 25: 2104–2117. doi: 10.1634/stemcells.2006-0726
- Issue published online: 2 JAN 2009
- Article first published online: 17 MAY 2007
- Manuscript Accepted: 4 MAY 2007
- Manuscript Received: 8 NOV 2006
- Adult neurogenesis;
- Neural stem/progenitor cells;
- Stem/progenitor cell transplantation;
- Stem cell aging Stem cell differentiation
Neurogenesis in the dentate gyrus (DG) declines severely by middle age, potentially because of age-related changes in the DG microenvironment. We hypothesize that providing fresh glial restricted progenitors (GRPs) or neural stem cells (NSCs) to the aging hippocampus via grafting enriches the DG microenvironment and thereby stimulates the production of new granule cells from endogenous NSCs. The GRPs isolated from the spinal cords of embryonic day 13.5 transgenic F344 rats expressing human alkaline phosphatase gene and NSCs isolated from embryonic day 9 caudal neural tubes of Sox-2:EGFP transgenic mice were expanded in vitro and grafted into the hippocampi of middle-aged (12 months old) F344 rats. Both types of grafts survived well, and grafted NSCs in addition migrated to all layers of the hippocampus. Phenotypic characterization revealed that both GRPs and NSCs differentiated predominantly into astrocytes and oligodendrocytic progenitors. Neuronal differentiation of graft-derived cells was mostly absent except in the dentate subgranular zone (SGZ), where some of the migrated NSCs but not GRPs differentiated into neurons. Analyses of the numbers of newly born neurons in the DG using 5′-bromodeoxyuridine and/or doublecortin assays, however, demonstrated considerably increased dentate neurogenesis in animals receiving grafts of GRPs or NSCs in comparison with both naïve controls and animals receiving sham-grafting surgery. Thus, both GRPs and NSCs survive well, differentiate predominantly into glia, and stimulate the endogenous NSCs in the SGZ to produce more new dentate granule cells following grafting into the aging hippocampus. Grafting of GRPs or NSCs therefore provides an attractive approach for improving neurogenesis in the aging hippocampus.
Disclosure of potential conflicts of interest is found at the end of this article.