A High Concentration of Epidermal Growth Factor Increases the Growth and Survival of Neurogenic Radial Glial Cells Within Human Neurosphere Cultures

Abstract

Human neural progenitor cells (hNPC) isolated from the fetal cortex can be expanded as aggregates of cells termed neurospheres. Traditional methods have used 20 ng/ml epidermal growth factor (EGF) to drive the proliferation of these cells. Here, we show that 100 ng/ml EGF can significantly increase growth rates of hNPC at later passages. This was through increased survival of dividing cells rather than increased proliferation and associated with prolonged activation of ErbB2 and phosphorylated Akt. High EGF also resulted in a larger proportion of elongated "radial glial"-like cells within the growing neurospheres and increased expression of the radial glial markers. The number of new neurons generated from cultures maintained in 100 ng/ml EGF was significantly higher than from 20 ng/ml EGF. Thus, high concentrations of EGF increase the survival of a highly neurogenic human radial glial cell. STEM CELLS 2008;26:348 -355 Disclosure of potential conflicts of interest is found at the end of this article.

In VitroRegulation of Neural Differentiation and Axon Growth by Growth Factors and Bioactive Nanofibers

“…There is evidence that biochemical factors can promote stem cell differentiation into various stages and types of neural cells 3,4 such as neural progenitor cells (NPCs), 5,6 mature neurons, 7 dopaminergic neurons, 8 and glial cells. 9 However, the exact roles of various growth factors in neural differentiation remain to be elucidated to improve the efficiency of cell differentiation. Among the studies on neural differentiation, basic fibroblast growth factor (bFGF) is known to be an important growth factor that increases neurite extensions in PC12 cells, 10 increases neurogenesis from human NPCs, 11 and stimulates neural cell differentiation.…”

“…4 Early studies in rat 13 and mouse 14 models have shown that sustained EGF treatment increases NPC differentiation into the glial lineage, and more recent studies with human NPCs show an increase in radial glial differentiation. 9 In this study, we directly compared the effects of bFGF and EGF on gene expression of neural markers during human ESC differentiation, and determined their effects on axon growth.…”

Human Neural Progenitor Cells: Mitotic and Neurogenic Effects of Growth Factors, Neurosteroids, and Excitatory Amino Acids

“…This possibility was also confirmed in another paper using culture with a high concentration of EGF, which also increased neural production in hNPCs [59]. Traditional methods have used 20 ng ml −1 EGF to drive the proliferation of neurospheres.…”

“…We recently found that there are different types of cells in proliferating hNPCs by using double labeling with GFAP and nestin following acute plating [50,59]. We found that in undifferentiated progenitor cells there are three different morphologies in hNPCs: (i) small and flat, (ii) elongated and radial, or (iii) large and flat cells (Figure 19.4e) [59].…”

“…We found that in undifferentiated progenitor cells there are three different morphologies in hNPCs: (i) small and flat, (ii) elongated and radial, or (iii) large and flat cells (Figure 19.4e) [59]. During the process of analyzing glutamate effects on hNPCs, we hypothesized that DHEA and glutamate treatment, which increased neural production in culture, may mainly affect the elongated progenitor cells possessing morphological characteristics like those of radial glial cells.…”