Highly efficient induction of functionally mature excitatory neurons from feeder-free human ES/iPS cells
Cortical excitatory neurons (Cx neurons) are the most dominant neuronal cell type in the cerebral cortex, which play a central role in cognition, perception, intellectual behavior and emotional processing. Robust in vitro induction of Cx neurons may facilitate as a tool for the elucidation of brain development and pathomechanism of the intractable neurodevelopmental and neurodegenerative disorders including Alzheimers disease, and thus potentially contribute to drug development. Here, we report a defined method for efficient induction of Cx neurons from the feeder-free-conditioned human embryonic stem cells (ES cells) and induced pluripotent stem cells (iPS cells). By using this method, human ES/iPS cells could be differentiated into ~99% MAP2-positive neurons by three weeks, and these induced neurons, within five weeks, presented various characteristics of mature excitatory neurons such as strong expression of glutamatergic neuron-specific markers (subunits of AMPA and NDMA receptors and CAMKII), highly synchronized spontaneous firing and excitatory postsynaptic current (EPSC). Moreover, the Cx neurons showed susceptibility to the toxicity of A{beta}42 oligomers and excitotoxicity of excessive glutamates, which is another advantage in terms of toxicity test and searching for the therapeutic agents. Taken together, this study provides a novel research platform for the study of neural development and degeneration based on the feeder-free human ES/iPS cell system.