Neural stem cells in early development

Neural stem cells (NSCs) undergo self-renewal and give rise to all differentiated cell types including astrocytes, oligodendrocytes and neurons in the nervous system. Their capacity of active proliferation and differentiation into multiple phenotypes makes them ideal candidates for clinical application such as replacement in many neurodegenerative disorders and other diseases of the nervous system. Various populations of NSCs can be isolated from different positions along the rostrocaudal axis in both embryonic and adult central nervous system (CNS). For my thesis work, I have taken advantage of a pure population of neuroepithelial cells (NEP), a type of embryonic NSCs isolated from rat E10.5 neural tube to address several aspects of stem cell biology. First, NEP cells were examined to identify markers which are unique to NSCs. Multiple markers were tested including many utilized for isolating hematopoietic stem cells (HSCs). I then analyzed membrane properties of NEP cells by examining ion channel gene expression using a focused microarray and current recording with whole cell patch clamping. To extend the understanding of NEP cells and to search for possible new NSC markers. My colleagues and I used several focused microarrays to compare the NEP cells expression pattern with a mixed population of El4.5 spinal cord cells containing both neuronal restricted precursor (NRP) and glial restricted precursor (GRP) cells. Finally, to determine how NEP cells differentiate into glial lineage, I used a PCR-based subtractive suppression hybridization (SSH) to identify differently expressed genes and several glial specific genes were identified and characterized. My results broaden the understanding of fetal NSCs by enlarging the marker pool for characterizing and providing new methods for isolating fetal NSCs from mixture populations. Similar experiments performed in adults will deepen the understanding of NSCs of the molecular mechanism regulating cell fate decisions.