Generation of functionally mature neurons from a telomerase-immortalized human glial progenitor cell line

BACKGROUND: It has long been thought that neurons and glial cells are produced from distinct progenitor pools, but recent studies suggest that the glial progenitor cell in the subventricular zone can generate neurons in the adult rodent brain. OBJECTIVE: To investigate the ability of a telomerase-immortalized human glial progenitor cell line to differentiate into functionally mature neurons. DESIGN, TIME AND SETTING: The cellular and molecular biology experiment was performed at the Cell Biology Laboratory in the School of Basic Medical Sciences, Peking University Health Science Center, between July 2007 and May 2008. MATERIALS: A telomerase reverse transcriptase immortalized human glial progenitor cell line, was established in our laboratory. Dibutyryl cyclic AMP was purchased from Sigma (USA). Specific antibodies against glial fibrillary acidic protein, beta-tubulin-III and A2B5 were purchased from Chemicon, USA. Polyclonal antibodies against nestin and MAP2ab were obtained from Neomarker, USA. METHODS: The telomerase immortalized human glial progenitor cell line was passaged and maintained in growth medium consisting of DMEM/F12 (1:1) with NZ supplement (1%, v/v), L-Glutamine (2 mmol/L), epidermal growth factor (20 ng/mL), basic fibroblast growth factor (20 ng/mL) and 3% fetal bovine serum. Neuronal differentiation was induced by the addition of 1 mmol/L dibutyryl cyclic AMP and 10% fetal bovine serum. MAIN OUTCOME MEASURES: Neuronal differentiation was evaluated by RT-PCR, quantitative PCR, immunofluorescence staining, Western blot analysis and electrophysiology. RESULTS: After dibutyryl cyclic AMP induction in the telomerase immortalized human glial progenitor cells, the expression of neuronal-specific marker mRNAs and proteins increased significantly. Concurrently, an apparent fast inward Na+ current was evoked in the cells after induction. CONCLUSION: This study suggests that some human glial progenitor cells are indeed capable of generating functionally mature neurons, and such cells may be useful for treating human neurological disorders.