Abnormal levels of fibroblast growth factors (FGFs) and FGF receptors (FGFRs) have been detected in various neurological disorders. The potent impact of FGF-FGFR in multiple embryonic developmental processes makes it challenging to elucidate their roles in postmitotic neurons. Taking an alternative approach to examine the impact of aberrant FGFR function on glutamatergic neurons, we generated a FGFR gain-of-function (GOF) transgenic mouse, which expresses constitutively activated FGFR3 (FGFR3) in postmitotic glutamatergic neurons. We found that GOF disrupts mitosis of radial-glia neural progenitors (RGCs), inside-out radial migration of post-mitotic glutamatergic neurons, and axonal tract projections. In particular, late-born CUX1-positive neurons are widely dispersed throughout the GOF cortex. Such a cortical migration deficit is likely caused, at least in part, by a significant reduction of the radial processes projecting from RGCs. RNA-sequencing analysis of the GOF embryonic cortex reveals significant alterations in several pathways involved in cell cycle regulation and axonal pathfinding. Collectively, our data suggest that FGFR3 GOF in postmitotic neurons not only alters axonal growth of postmitotic neurons but also impairs RGC neurogenesis and radial glia processes.
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http://dx.doi.org/10.1038/s41598-020-75537-0 | DOI Listing |
Unlabelled: The neurodegenerative disorder Frontotemporal Dementia (FTD) can be caused by a repeat expansion (GGGGCC; G4C2) in C9orf72. The function of wild-type C9orf72 and the mechanism by which the C9orf72-G4C2 mutation causes FTD, however, remain unresolved. Diverse disease models including human brain samples and differentiated neurons from patient-derived induced pluripotent stem cells (iPSCs) identified some hallmarks associated with FTD, but these models have limitations, including biopsies capturing only a static snapshot of dynamic processes and differentiated neurons being labor-intensive, costly, and post-mitotic.
View Article and Find Full Text PDFDev Biol
January 2025
Biology Department, Texas A&M University, College Station, TX 7843-3258. Electronic address:
During development of the vertebrate inner ear, sensory epithelia and neurons of the statoacoustic ganglion (SAG) arise from lineage-restricted progenitors that proliferate extensively before differentiating into mature post-mitotic cell types. Development of progenitors is regulated by Fgf, Wnt and Notch signaling, but how these pathways are coordinated to achieve an optimal balance of proliferation and differentiation is not well understood. Here we investigate the role in zebrafish of Foxm1, a transcription factor commonly associated with proliferation in developing tissues and tumors.
View Article and Find Full Text PDFPLoS Biol
January 2025
Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America.
Throughout the animal kingdom, several members of the basic helix-loop-helix (bHLH) family act as proneural genes during early steps of nervous system development. Roles of bHLH genes in specifying terminal differentiation of postmitotic neurons have been less extensively studied. We analyze here the function of 5 Caenorhabditis elegans bHLH genes, falling into 3 phylogenetically conserved subfamilies, which are continuously expressed in a very small number of postmitotic neurons in the central nervous system.
View Article and Find Full Text PDFCell Rep
January 2025
Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA; Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address:
Neurogenic microRNAs 9/9 and 124 (miR-9/9-124) drive the direct reprogramming of human fibroblasts into neurons with the initiation of the fate erasure of fibroblasts. However, whether the miR-9/9-124 fate erasure logic extends to the neuronal conversion of other somatic cell types remains unknown. Here, we uncover that miR-9/9-124 induces neuronal conversion of multiple cell types: dura fibroblasts, astrocytes, smooth muscle cells, and pericytes.
View Article and Find Full Text PDFGenes Dev
December 2024
Howard Hughes Medical Institute, Department of Biological Sciences, Columbia University, New York, New York 10025, USA.
The pan-neuronally expressed and phylogenetically conserved CUT homeobox gene orchestrates pan-neuronal gene expression throughout the nervous system of As in many other species, including humans, is encoded by a complex locus that also codes for a Golgi-localized protein, called CASP (Cux1 alternatively spliced product) in humans and CONE-1 ("CASP of nematodes") in How gene expression from this complex locus is controlled-and, in , directed to all cells of the nervous system-has not been investigated. We show here that pan-neuronal expression of CEH-44/CUX is controlled by a pan-neuronal RNA splicing factor, UNC-75, the homolog of vertebrate CELF proteins. During embryogenesis, the locus exclusively produces the Golgi-localized CONE-1/CASP protein in all tissues, but upon the onset of postmitotic terminal differentiation of neurons, UNC-75/CELF induces the production of the alternative CEH-44/CUX CUT homeobox gene-encoding transcript exclusively in the nervous system.
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