Evidence that Embryonic Neurons Regulate the Onset of Cortical Gliogenesis via Cardiotrophin-1

• Published in: Neuron (Cambridge, Mass.) Mass.), 2005-10, Vol.48 (2), p.253-265
• Main Authors: Barnabé-Heider, Fanie, Wasylnka, Julie A., Fernandes, Karl J.L., Porsche, Christian, Sendtner, Michael, Kaplan, David R., Miller, Freda D.
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animals; Blotting, Western - methods; Cell Count - methods; Cell Differentiation - drug effects; Cell Differentiation - physiology; Cells, Cultured; Cerebral Cortex - cytology; Cerebral Cortex - embryology; Ciliary Neurotrophic Factor - pharmacology; Cloning; Contactins; Culture Media, Conditioned - pharmacology; Cyclin-Dependent Kinase 2 - metabolism; Cyclin-dependent kinases; Cytokines; Cytokines - deficiency; Cytokines - pharmacology; Cytokines - physiology; Drug Interactions; ELAV Proteins - metabolism; Embryo, Mammalian; Enzyme Activation - physiology; Enzyme Inhibitors - pharmacology; Flavonoids - pharmacology; Fluorescent Antibody Technique - methods; Glial Fibrillary Acidic Protein - metabolism; Green Fluorescent Proteins - metabolism; Hyaluronan Receptors - metabolism; Hypotheses; Interleukin-6 - pharmacology; Intermediate Filament Proteins - metabolism; Kinases; Leukemia; Leukemia Inhibitory Factor; Mice; Mice, Transgenic; Nerve Growth Factors - metabolism; Nerve Tissue Proteins - metabolism; Nestin; Neural Cell Adhesion Molecules - metabolism; Neurofilament Proteins - metabolism; Neurogenesis; Neuroglia - physiology; Neurons; Neurons - physiology; Organogenesis; Phosphopyruvate Hydratase - metabolism; Protein-Tyrosine Kinases - metabolism; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA, Messenger - biosynthesis; RNA, Small Interfering - pharmacology; S100 Calcium Binding Protein beta Subunit; S100 Proteins - metabolism; Software; STAT Transcription Factors - metabolism; Stem Cells - drug effects; Time Factors; Transfection - methods; Tubulin - metabolism; Tyrphostins - pharmacology
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2005.08.037

Precursor cells of the embryonic cortex sequentially generate neurons and then glial cells, but the mechanisms regulating this neurogenic-to-gliogenic transition are unclear. Using cortical precursor cultures, which temporally mimic this in vivo differentiation pattern, we demonstrate that cortical neurons synthesize and secrete the neurotrophic cytokine cardiotrophin-1, which activates the gp130-JAK-STAT pathway and is essential for the timed genesis of astrocytes in vitro. Our data indicate that a similar phenomenon also occurs in vivo. In utero electroporation of neurotrophic cytokines in the environment of embryonic cortical precursors causes premature gliogenesis, while acute perturbation of gp130 in cortical precursors delays the normal timed appearance of astrocytes. Moreover, the neonatal cardiotrophin-1 −/− cortex contains fewer astrocytes. Together, these results describe a neural feedback mechanism; newly born neurons produce cardiotrophin-1, which instructs multipotent cortical precursors to generate astrocytes, thereby ensuring that gliogenesis does not occur until neurogenesis is largely complete.