Hypothalamic gonadotropin-releasing hormone (GnRH) neurons control pituitary gonadotropin secretion and gametogenesis. In the course of development, these neurons migrate from the olfactory placode to the hypothalamus. The precise molecular mechanism of this neuronal migration is unclear. Here, we investigated whether the chemokine receptor, Cxcr4b, and its cognate ligand, Cxcl12a, are required for proper migration of GnRH3 neurons in zebrafish. Deviated GnRH3 axonal projections and neuronal migration were detected in larvae that carry a homozygote cxcr4b mutation. Similarly, knockdown of Cxcr4b or Cxcl12a led to the appearance of abnormal GnRH3 axonal projections and cell migration, including absence of the characteristic lateral crossing of GnRH3 axons at the anterior commissure and optic chiasm. Double-labeling analysis has shown that cxcr4b and cxcl12a are expressed along the GnRH3 migration pathway (i.e. olfactory placode, terminal nerve and the optic chiasm). The results of this study suggest that the Cxcl12a-Cxcr4b ligand-receptor pair are involved in the migration of GnRH3 neurons in zebrafish, and are therefore crucial for the development of this system.
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http://dx.doi.org/10.1016/j.ygcen.2009.07.001 | DOI Listing |
Elife
December 2024
Sorbonne Université, Centre National de la Recherche Scientifique (CNRS UMR7622), Institut de Biologie Paris-Seine (IBPS), Developmental Biology Laboratory, Paris, France.
Despite recent progress, the complex roles played by the extracellular matrix in development and disease are still far from being fully understood. Here, we took advantage of the zebrafish mutation which affects Laminin γ1, a major component of basement membranes, to explore its role in the development of the olfactory system. Following a detailed characterisation of Laminin distribution in the developing olfactory circuit, we analysed basement membrane integrity, olfactory placode and brain morphogenesis, and olfactory axon development in mutants, using a combination of immunochemistry, electron microscopy and quantitative live imaging of cell movements and axon behaviours.
View Article and Find Full Text PDFDifferentiation
December 2024
School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits, 2050, Johannesburg, South Africa. Electronic address:
The Fibroblast growth factor (FGFs) family consists of at least 22 members that exert their function by binding and activating fibroblast growth factor receptors (FGFRs). The Fgf8/FgfD subfamily member, Fgf17, is located on human chromosome 8p21.3 and mouse chromosome 14 D2.
View Article and Find Full Text PDFDespite recent progress, the complex roles played by the extracellular matrix in development and disease are still far from being fully understood. Here, we took advantage of the zebrafish mutation which affects Laminin γ1, a major component of basement membranes, to explore its role in the development of the olfactory system. Following a detailed characterisation of Laminin distribution in the developing olfactory circuit, we analysed basement membrane integrity, olfactory placode and brain morphogenesis, and olfactory axon development in mutants, using a combination of immunochemistry, electron microscopy and quantitative live imaging of cell movements and axon behaviours.
View Article and Find Full Text PDFInt J Surg Case Rep
June 2024
Department of Ear, Nose, Throat and Head and Neck Surgery, Farhat Hached University Hospital, Sousse, Tunisia.
Introduction And Importance: Olfactory neuroblastoma or esthesioneuroblastoma is a rare malignant tumour, that develops in the olfactory neuroepithelium and is one of the rarest tumours of the nasal cavity. Ocular manifestations are uncommon. The diagnosis is based on histology: biopsy, immunohistochemistry and ultrastructural findings.
View Article and Find Full Text PDFUnlabelled: The mammalian olfactory neuronal lineage is regenerative, and accordingly, maintains a population of pluripotent cells that replenish olfactory sensory neurons and other olfactory cell types during the life of the animal. Moreover, in response to acute injury, the early transit amplifying cells along the olfactory sensory neuronal lineage are able to de-differentiate to shift resources in support of tissue restoration. In order to further explore plasticity of various cellular stages along the olfactory sensory neuronal lineage, we challenged the epigenetic stability of two olfactory placode-derived cell lines that model immature olfactory sensory neuronal stages.
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