Selective and rapid expansion of human neural progenitor cells on substrates with terminally anchored growth factors

Human neural progenitor cells (hNPCs) are a potential source for cell transplantation therapy in central nervous disorders. Neurosphere culture, the standard method for obtaining hNPCs, suffers from several limitations including the heterogeneity of cells in a neurosphere and the limitation of growth rate due to the presence of differentiated cells in the neurospheres. To overcome these limitations, we developed culture substrates that enable the selective expansion of hNPCs in adherent culture. Epidermal growth factor and basic fibroblast growth factor were fused with hexahistidine (EGF-His and bFGF-His, respectively) and were immobilized alone or in combination onto Ni ion-bound glass through coordination. When hNPCs derived from human fetal brain were cultured on these substrates, adhesion and proliferation of hNPCs took place most efficiently on the substrate with both EGF-His and bFGF-His compared to substrates with either factor alone and to a control substrate without growth factors. The rate of cell proliferation was two-fold higher in the adherent culture on the substrate immobilized with both EGF-His and bFGF-His than in the standard neurosphere culture. A cell population obtained after 5 days of culture on the substrate contained nestin-expressing progenitors (>90%). We conclude that the culture substrate with co-immobilized EGF and bFGF is effective for the selective expansion of hNPCs.