Browsing by Subject "Interpeduncular nucleus"

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    Multiple regionalized genes and their putative Networks in the interpeduncular nucleus suggest complex mechanisms of neuron development and axon guidance
    (Frontiers Media, 2021-02-16) García-Guillén, Isabel M.; Puelles López, Luis; Alonso Fuentes, Antonia; Aroca Tejedor, Pilar; Marín San Leandro, Faustino; Anatomía Humana y Psicobiología
    The interpeduncular nucleus (IPN) is a highly conserved limbic structure in the vertebrate brain, located in the isthmus and rhombomere 1. It is formed by various populations that migrate from different sites to the distinct domains within the IPN: the prodromal, rostral interpeduncular, and caudal interpeduncular nuclei. The aim here was to identify genes that are differentially expressed across these domains, characterizing their putative functional roles and interactions. To this end, we screened the 2,038 genes in the Allen Developing Mouse Brain Atlas database expressed at E18.5 and we identified 135 genes expressed within the IPN. The functional analysis of these genes highlighted an overrepresentation of gene families related to neuron development, cell morphogenesis and axon guidance. The interactome analysis within each IPN domain yielded specific networks that mainly involve members of the ephrin/Eph and Cadherin families, transcription factors and molecules related to synaptic neurotransmission. These results bring to light specific mechanisms that might participate in the formation, molecular regionalization, axon guidance and connectivity of the different IPN domains. This genoarchitectonic model of the IPN enables data on gene expression and interactions to be integrated and interpreted, providing a basis for the further study of the connectivity and function of this poorly understood nuclear complex under both normal and pathological conditions.
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    Netrin-1/DCC signaling differentially regulates the migration of Pax7, Nkx6.1, Irx2, Otp and Otx2 cell populations in the developing interpeduncular nucleus
    (Frontiers Media, 2020-10-20) García-Guillén, Isabel M.; Morales-Delgado, Nicanor; Andrés, Belén; Puelles López, Luis; López-Bendito, Guillermina; Alonso Fuentes, Antonia; Aroca Tejedor, Pilar; Marín San Leandro, Faustino; Anatomía Humana y Psicobiología
    The interpeduncular nucleus (IPN) is a hindbrain structure formed by three main subdivisions, the prodromal (Pro) domain located at the isthmus (Ist), and the rostral and caudal interpeduncular domains (IPR, IPC) within rhombomere 1 (r1). Various cell populations can be detected in the IPN through the expression of the Nkx6.1, Otp, Otx2, Pax7, and/or Irx2 transcription factors. These cell populations follow independent dorsoventral tangential and radial migratory routes targeting the ventral paramedian region of Ist and r1. Here we set out to examine the influence of the Netrin-1/DCC pathway on these migrations, since it is known to regulate other processes of neuronal migration in the brain. To this end, we analyzed IPN development in late gestational wild-type and DCC-/- mice, using mainly in situ hybridization (ISH) to identify the cells expressing each of the aforementioned genes. We found that the migration of Nkx6.1 + and Irx2 + cells into the Pro domain was strongly disrupted by the loss of DCC, as occurred with the migration of Pax7 +, Irx2 +, and Otp + cells that would normally form the IPR. In addition, there was mild impairment of the migration of the Pax7 + and Otx2 + cells that form the IPC. These results demonstrate that the Netrin-1/DCC signaling pathway is involved in the migration of most of the IPN populations, mainly affecting those of the Pro and IPR domains of this nucleus. There are psychiatric disorders that involve the medial habenula (mHb)-IPN system, so that this experimental model could provide a basis to study their neurodevelopmental etiology.