RESUMEN
The pluripotency and high proliferative capacity of embryonic stem (ES) cells (1-3) makes them an attractive source of different cell types for biomedical research and cell replacement therapies. A major prerequisite for these applications is the availability of a homogeneous population of the desired cell type. However, ES cell-derived material contains, for example, undifferentiated cells, which can cause tumor formation after transplantation into the brain (4). To avoid such unwanted side effects, effective purification of distinct types of cells needs to be developed. Here, we describe an immunoisolation procedure to purify neurons from in vitro differentiated mouse ES cells using an antibody against the neuronal cell adhesion molecule L1 (5, 6). Our procedure yields a pure population of differentiated neurons, which are electrically excitable and form excitatory, glutamatergic, and inhibitory GABAergic synapses. The ability to highly purify ES cell-derived neurons will boost their molecular characterization and the further exploration of their therapeutic potential.
Asunto(s)
Embrión de Mamíferos/citología , Neuronas/fisiología , Células Madre/fisiología , Potenciales de Acción , Animales , Anticuerpos Monoclonales , Diferenciación Celular , Inmunohistoquímica , Ratones , Molécula L1 de Adhesión de Célula Nerviosa/inmunología , Proteínas de Neurofilamentos/inmunología , Proteínas de Neurofilamentos/metabolismo , Neuronas/citología , Técnicas de Placa-Clamp , Receptores de GABA-A/fisiología , Receptores de Glutamato/fisiología , Sinapsis/fisiologíaRESUMEN
Brain development and function relies on the exchange of signals between neurons and glial cells. Here we review a series of recent studies on cultures of purified retinal ganglion cells (RGCs) that point to a new role of glial cells in the formation and plasticity of synaptic connections. The results suggest that neurons must import glia-derived cholesterol via lipoproteins to form numerous and efficient synaptic connections. This finding may explain why throughout the central nervous system (CNS) the main phase of synaptogenesis starts synchronously after glia differentiation and why astrocytes produce apolipoprotein E (apoE) and cholesterol-containing lipoproteins. Experimental tests of these hypotheses may further our understanding of the cholesterol metabolism in the brain and may help to explain neurologic symptoms resulting from defective cholesterol and lipoprotein metabolism.