14/07/2021
During development, intercellular cross-talk results in the generation and transmission of specific signals from a cell to its neighbor, altering in some key way the subsequent behavior of the neighbor. Of prime importance is sifting through the galaxy of environmental signals to determine which constellations of cues can selectively coax ES cells down a specific cell lineage pathway at the expense of all others. To this end
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were recently able to obtain pure populations of multipotent progenitor cells expressing glial precursor markers. They achieved this goal by taking aggregates of cultured mouse ES cells and propagating them sequentially in medium containing first fibroblast growth factor (FGF) 2 alone, then a mixture of FGF2 and epidermal growth factor (EGF), and finally a mix of FGF2 and platelet-derived growth factor (PDGF). Bathed in this last broth of growth factors, these pluripotent cells could be maintained for many generations in culture. Upon growth factor withdrawal, they subsequently differentiated into either of two specific lineages, oligodendrocytes or astrocytes (
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).
Illustrating the enormous potential of this type of research for clinical application, McKay and coworkers transplanted these cloned glial precursor cells into the ventricle of myelin-deficient rats. Myelin sheaths formed around host axons in various brain regions, including cortex, hippocampus, and hypothalamus (Figure 2;
