Loss of glutamatergic pyramidal neurons in frontal and temporal cortex resulting from attenuation of FGFR1 signaling is associated with spontaneous hyperactivity in mice.
Fibroblast growth factor receptor (FGFR) gene products (Fgfr1, Fgfr2, Fgfr3) are widely expressed by embryonic neural progenitor cells throughout the CNS, yet their functional role in cerebral cortical development is still unclear. To understand whether the FGF pathways play a role in cortical development, we attenuated FGFR signaling by expressing a tyrosine kinase domain-deficient Fgfr1 (tFgfr1) gene construct during embryonic brain development. Mice carrying the tFgfr1 transgene under the control of the Otx1 gene promoter have decreased thickness of the cerebral cortex in frontal and temporal areas because of decreased number of pyramidal neurons and disorganization of pyramidal cell dendritic architecture. These alterations may be, in part, attributable to decreased genesis of T-Brain-1-positive early glutamatergic neurons and, in part, to a failure to maintain radial glia fibers in medial prefrontal and temporal areas of the cortical plate. No changes were detected in cortical GABAergic interneurons, including Cajal-Retzius cells or in the basal ganglia. Behaviorally, tFgfr1 transgenic mice displayed spontaneous and persistent locomotor hyperactivity that apparently was not attributable to alterations in subcortical monoaminergic systems, because transgenic animals responded to both amphetamine and guanfacine, an alpha2A adrenergic receptor agonist. We conclude that FGF tyrosine kinase signaling may be required for the genesis and growth of pyramidal neurons in frontal and temporal cortical areas, and that alterations in cortical development attributable to disrupted FGF signaling are critical for the inhibitory regulation of motor behavior.
Child Study Center, Yale University, New Haven, Connecticut 06520, USA.
Dana M
DM
Shin
Sailaja
S
Korada
Rossana
R
Raballo
Cooduvalli S
CS
Shashikant
Antonio
A
Simeone
Jane R
JR
Taylor
Flora
F
Vaccarino
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000661:Amphetamine; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division; D005625:Frontal Lobe / Q000002:abnormalities / Q000378:metabolism* / Q000473:pathology; D018698:Glutamic Acid / Q000378:metabolism; D016316:Guanfacine / Q000494:pharmacology; D006801:Humans; D006948:Hyperkinesis / Q000139:chemically induced / Q000188:drug therapy / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D009421:Nervous System Malformations / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009433:Neural Inhibition / Q000235:genetics; D017966:Pyramidal Cells / Q000378:metabolism* / Q000473:pathology; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D051496:Receptor, Fibroblast Growth Factor, Type 1; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D019956:Stereotypic Movement Disorder / Q000139:chemically induced / Q000188:drug therapy / Q000235:genetics; D013702:Temporal Lobe / Q000002:abnormalities / Q000378:metabolism* / Q000473:pathology
D000316:Adrenergic alpha-Agonists; D018341:Receptors, Adrenergic, alpha-2; D017468:Receptors, Fibroblast Growth Factor; D016316:Guanfacine; D018698:Glutamic Acid; D000661:Amphetamine; C496348:FGFR1 protein, human; C496349:Fgfr1 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1