Abstract
Nestin-expressing neural progenitor (NP) cells have been isolated from the subventricular zone (SVZ) of the brain and propagated with epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF). In other neural cell types it has been shown that EGF and bFGF activate cell surface receptors involved in the mitogen-activated protein kinase (MAPK) signal pathway. To examine this issue in NP cells, we isolated primary SVZ cells and stimulated them with EGF and bFGF and then used a phosphorylation-specific antibody to detect activated MAPK by immunofluorescent staining or Western blotting. The addition of growth factors activated MAPK transiently in cells that co-expressed nestin. A distinct phospho-MAPK signal was also detected in nestin-positive cells with mitotic chromosomes. A novel MAPK kinase (MEK1) inhibitor U0126 blocked the activation of MAPK and the proliferation of primary cells more effectively than the same concentration of PD98059. After exposure of cells to U0126 for 10 days, we noted that there was a significant reduction in the number of cells that expressed nestin and an increase in the percentage of apoptotic cells. These data provide evidence that activation of MAPK by MEK1 is important for the proliferation of NP cells.
MeSH terms
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Animals
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Apoptosis / drug effects
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Apoptosis / physiology
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Astrocytes / cytology
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Astrocytes / enzymology
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Butadienes / pharmacology
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Cell Differentiation / drug effects
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Cell Differentiation / physiology
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Cell Division / drug effects
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Cell Division / physiology
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Cells, Cultured
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Enzyme Activation / drug effects
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Enzyme Inhibitors / pharmacology
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Epidermal Growth Factor / pharmacology
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Female
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Fetus / cytology
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Fibroblast Growth Factor 2 / pharmacology
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Flavonoids / pharmacology
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In Situ Nick-End Labeling
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Intermediate Filament Proteins / biosynthesis
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MAP Kinase Kinase 1
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Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors*
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Mitogen-Activated Protein Kinase Kinases / metabolism
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Nerve Tissue Proteins*
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Nestin
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Neurons / cytology*
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Neurons / enzymology*
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Nitriles / pharmacology
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Oligodendroglia / cytology
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Oligodendroglia / enzymology
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Phosphorylation
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Pregnancy
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Protein Serine-Threonine Kinases / antagonists & inhibitors*
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Protein Serine-Threonine Kinases / metabolism
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Rats
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Rats, Sprague-Dawley
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Stem Cells / cytology*
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Stem Cells / enzymology*
Substances
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Butadienes
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Enzyme Inhibitors
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Flavonoids
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Intermediate Filament Proteins
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Nerve Tissue Proteins
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Nes protein, rat
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Nestin
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Nitriles
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U 0126
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Fibroblast Growth Factor 2
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Epidermal Growth Factor
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Protein Serine-Threonine Kinases
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MAP Kinase Kinase 1
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Mitogen-Activated Protein Kinase Kinases
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2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one