Neuronal differentiation following transplantation of expanded mouse neurosphere cultures derived from different embryonic forebrain regions.
ABSTRACT In vitro, expanded neurospheres exhibit multipotent properties and can differentiate into neurons, astrocytes and oligodendrocytes. In vivo, cells from neurospheres derived from mouse fetal forebrain have previously been reported to predominantly differentiate into glial cells, and not into neurons. Here we isolated stem/progenitor cells from E13.5 lateral ganglionic eminence (LGE), medial ganglionic eminence (MGE) and cortical primordium, of a green fluorescent protein (GFP)-actin transgenic mouse. Free-floating neurospheres were expanded in the presence of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) and implanted after five to six passages into the striatum, hippocampus and cortex of neonatal rats. Cell suspensions of primary LGE tissue were prepared and grafted in parallel. Grafted cells derived from the primary tissue displayed widespread incorporation into all regions, as visualized with the mouse-specific antibody M2, or mouse satellite DNA in situ hybridization, and differentiated into both neurons, astrocytes and oligodendrocytes. Grafts of neurosphere cells derived from the LGE, MGE and cortical primordium differentiated primarily into astrocytes, but contained low but significant numbers of GFP-immunoreactive neurons. Neurons derived from LGE neurospheres were of three types: cells with the morphology of medium-sized densely spiny projection neurons in the striatum; cells with interneuron-like morphologies in striatum, cortex and hippocampus; and cells integrating into SVZ and migrating along the RMS to the olfactory bulb. MGE- or cortical primordium-derived neurospheres differentiated into interneuron-like cells in both striatum and hippocampus. The results demonstrate the ability of in vitro expanded neural stem/progenitor cells to generate both neurons and glia after transplantation into neonatal recipients, and differentiate in a region-specific manner into mature neurons with morphological features characteristic for each target site.
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ABSTRACT: We have studied the molecular specification of precursor cells in expanded neurosphere cultures derived from distinct subregions of the embryonic mouse telencephalon. These regionally derived cultures exhibited differential responses to the mitogens EGF and bFGF, suggesting that the precursors in these cultures were differentially specified as is the case in situ. To examine this further, cultures from each of the telencephalic subregions were expanded in both EGF and bFGF before differentiation. The neurons produced displayed molecular phenotypes similar to those normally derived from each of these regions in vivo. Moreover, analysis of gene expression in the undifferentiated cultures showed that the regionally derived neurospheres express many of the same developmental control genes as their in vivo counterparts. Taken together, the present findings suggest that precursor cells in neurosphere cultures, derived from distinct subregions of the embryonic telencephalon, maintain at least certain aspects of their molecular specification, even after significant expansion in vitro.Molecular and Cellular Neuroscience 01/2003; 21(4):645-56. · 3.84 Impact Factor
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ABSTRACT: We have isolated neural precursors from the striata of embryonic wild-type and transgenic mice ubiquitously expressing enhanced green fluorescent protein. Cells were expanded in vitro in the presence of epidermal growth factor and transplanted into the retina of young postnatal mice. One month after transplantation, cells showed widespread integration into the host tissue and differentiated into a variety of morphologically distinct cell types. A fraction of cells was identified as oligodendrocytes exclusively located in the immediate vicinity to the nerve fiber layer. Similar results were obtained with neural precursors isolated from embryonic spinal cord. Differentiated oligodendrocytes and myelin were still detectable in the host tissue 4 months after transplantation, the latest time point investigated. Remarkably, prolonged survival periods of experimental animals resulted in a significant increase in the number of donor-derived oligodendrocytes and the area of the nerve fiber layer being myelinated. The presence of high numbers of oligodendrocytes and their location close to the retinal nerve fiber layer suggest that the differentiation of transplanted neural precursors into distinct neural cell types is influenced by host-derived environmental cues.Glia 06/2000; 30(3):301-10. · 5.07 Impact Factor
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ABSTRACT: The stereotyped positions occupied by individual classes of neurons are a fundamental characteristic of CNS cytoarchitecture. To study the regulation of neuronal positioning, we injected genetically labeled neural precursors derived from dorsal and ventral mouse forebrain into the telencephalic vesicles of embryonic rats. Cells from both areas were found to participate in the generation of telencephalic, diencephalic, and mesencephalic brain regions. Donor-derived neurons populated the host brain in distinct patterns and acquired phenotypic features appropriate for their final location. These observations indicate that neuronal migration and differentiation are predominantly regulated by non-cell-autonomous signals. Exploiting this phenomenon, intrauterine transplantation allows generation of controlled chimerism in the mammalian brain.Neuron 01/1996; 15(6):1275-85. · 15.77 Impact Factor