The N-terminal region of reelin regulates postnatal dendritic maturation of cortical pyramidal neurons.
Cajal-Retzius cells, located in layer I of the cortex, synthesize and secrete the glycoprotein reelin, which plays a pivotal role in neuronal migration during embryonic development. Cajal-Retzius cells persist after birth, but their postnatal role is unknown. Here we show that Cajal-Retzius cells receive a major excitatory synaptic input via serotonin 5-HT(3) receptors. Blocking this input using pharmacological tools or neutralization of reelin signaling results in hypercomplexity of apical, but not basal, dendrites of cortical layer II/III pyramidal neurons. A similar hypercomplexity is observed in the cortex of the 5-HT(3A) receptor knockout mouse. The increased dendritic complexity can be rescued by application of recombinant full-length reelin or its N-terminal fragment, but not by the central fragment of reelin, and involves a signal transduction pathway independent of the activation of the canonical reelin receptors. Taken together, our results reveal a novel role of serotonin, Cajal-Retzius cells, and reelin in the postnatal maturation of the cortex.
Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, 1090 GE Amsterdam, The Netherlands.
Pascal
P
Chameau
Dragos
D
Inta
Tania
T
Vitalis
Hannah
H
Monyer
Wytse J
WJ
Wadman
Johannes A
JA
van Hooft
D000818:Animals; D000831:Animals, Newborn; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D003712:Dendrites / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D017966:Pyramidal Cells / Q000166:cytology* / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D000091042:Reelin Protein; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D046509:Tissue Culture Techniques
D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D044406:Receptors, Serotonin, 5-HT3; D000091042:Reelin Protein; C000717127:RELN protein, human; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases