Neurons differentiated from glia

Fig. 1 Basic processes of brain development necessary for proper organ function. Neural Progenitor Cells (NPCs, green) proliferate to provide an access amount of cells, which then migrate and differentiate into neurons (purple) and glia [yellow). These form synapses [red) and surplus cells undergo apoptosis (grey). When these processes happen in the right and coordinated way, functional neuronal networks form (olive). With courtesy from William Mundy, US Environmental Protection Agency and John Havel, SRA International, Inc.

Glia maturation factor beta (GMF-beta), first detected in this laboratory in 1972 (6-8), is an acidic protein with a molecular mass of 17 kDa present in brains of all vertebrates examined (9,10). GMF-beta promotes the differentiation of glia and neurons, and inhibits the growth of their corresponding tumors (11,12). Although GMF-beta was purified to homogeneity from bovine brain (11), it was not available in sufficient quantity for structural studies. Recently, GMF-beta has been completely sequenced... 

NTE is an integral membrane protein in neurons and some non-neural cell types of vertebrates [3,27,32] and its activity depends on lipid contents. It is present in all neurons, but is absent from glia [32], NTE can hydrolyze many esters of carboxylic acids. NTE is conveniently detected in vitro by its ability to catalyse OP-sensitive hydrolysis of an artificial substrate, phenyl valerate. Its activity is operationally defined as phenyl valerate hydrolysis resistant to inhibition by 0,0-diethyl-4-nitrophenyl phosphate (paraoxon, non-neuropathic) and sensitive to inhibition by NJ T-diisopropyl phosphorodiamidic fluoride (mipafox, neuropathic), determined under specified conditions [3]. Differential centrifugation of brain homogenates resulted in an enrichment of NTE in microsomal fractions containing elements of endoplasmic reticulum (ER), Goldgi, and plasma membrane [39],... 

Two recent reports suggest that neuronal precursor cells exist in the adult mammalian brain (Reynolds and Weiss, 1992 Richards et al., 1992). Reynolds and Weiss (1992) isolated cells from the striatum of the adult mouse brain and induced the in vitro proliferation of precursors with EGF in serum-free conditions. These cells were also demonstrated to have the capacity to differentiate into neurons and glia. Richards et al. (1992) reported that neuronal induction from murine cerebral precursors was optimal under in vitro conditions in which the cells were initially stimulated with... 

An especially interesting example of mitochondrial differentiation is seen in neuroglia and neurons from the cerebral cortex, for these cells stem from a near common ancestor —the neural epithelium. Mitochondria from neuron-enriched and glia-enriched cell fractions of beef and rabbit brains have been isolated. These mitochondria show no striking... 

NSCs isolated from fetal nervous tissue have the potential to differentiate into all types of nervous system cells, including neurons, oligodendrocytes, and astrocytes, so NSCs also have the capacity to replace damaged tissue in both the CNS and PNS. NSCs will restore functional neurons and glia and regenerate injured tissue. It is this characteristic of neural stem cells that makes them a potentially valuable transplantation material in a host of disorders. 

The number of commercially available NS/PC lines has been constantly increasing. The NSC lines ReNcell VM and ReNcell CX (Millipore) are derived from developing human brains, ReNcell VM from the ventral mesencephalon (VM) and ReNcell CX cells from the cortical (CX) regions of the brain. For immortalization, they were transduced with the myc transcription factor. ReNcell lines grow as adherent cultures and have the ability to differentiate into neurons and glia cells. Also hESC (EI9/derived... 

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