Search results for "NEURONAL MIGRATION"
showing 10 items of 14 documents
Microenvironments to study migration and somal translocation in cortical neurons
2018
Migrating post-mitotic neurons of the developing cerebral cortex undergo terminal somal translocation (ST) when they reach their final destination in the cortical plate. This process is crucial for proper cortical layering and its perturbation can lead to brain dysfunction. Here we present a reductionist biomaterials platform that faithfully supports and controls the distinct phases of terminal ST in vitro. We developed microenvironments with different adhesive molecules to support neuronal attachment, neurite extension, and migration in distinct manners. Efficient ST occurred when the leading process of migratory neurons crossed from low-to high-adhesive areas on a substrate, promoting spr…
Radial Glial Fibers Promote Neuronal Migration and Functional Recovery after Neonatal Brain Injury.
2018
Radial glia (RG) are embryonic neural stem cells (NSCs) that produce neuroblasts and provide fibers that act as a scaffold for neuroblast migration during embryonic development. Although they normally disappear soon after birth, here we found that RG fibers can persist in injured neonatal mouse brains and act as a scaffold for postnatal ventricular-subventricular zone (V-SVZ)-derived neuroblasts that migrate to the lesion site. This injury-induced maintenance of RG fibers has a limited time window during post-natal development and promotes directional saltatory movement of neuroblasts via N-cadherin-mediated cell-cell contacts that promote RhoA activation. Transplanting an N-cadherin-contai…
Efectos de la exposición crónica al etanol sobre el tráfico intracelular y citoesqueleto como factores implicados en la migración neuronal
2013
El consumo de etanol durante la gestación puede inducir una serie de alteraciones graves en el desarrollo del feto, la manifestación más extrema da lugar al Síndrome Alcohólico Fetal (SAF). La exposición prenatal al alcohol es la causa conocida y, además evitable, más importante de retraso mental en el mundo occidental. Además de déficits cognitivos, los niños con SAF presentan múltiples anomalías estructurales en el sistema nervioso central, como reducción de la masa cerebral, y a nivel celular, daños en la migración neuronal, en el proceso de formación de espinas dendríticas y establecimiento de sinapsis. En la actualidad, los mecanismos moleculares implicados en la teratogénesis inducida…
Lissencephalic syndromes: brain and beyond
2009
Lissencephaly has been long maintained a malformation involving only the brain. Classic lissencephaly includes agyria and pachygyria and it is the most severe form of malformations derived from abnormal neuronal migration. It is defined as a smooth or nearly smooth cerebral surface with absence of normal sulci and gyria. It encompasses a group of syndromes which show many different clinical conditions. Four groups are actually distinguished: classic lissencephaly variants, other lissencephalies including forms with unknown pathogenesis, microlissencephaly spectrum and Cobblestone cortical malformations. Several genes and proteins are involved in this syndromic spectrum and each year new mol…
Control of cortical neuronal migration by glutamate and GABA
2015
Neuronal migration in the cortex is controlled by the paracrine action of the classical neurotransmitters glutamate and GABA. Glutamate controls radial migration of pyramidal neurons by acting primarily on NMDA receptors and regulates tangential migration of inhibitory interneurons by activating non-NMDA and NMDA receptors. GABA, acting on ionotropic GABAA-rho and GABAA receptors, has a dichotomic action on radially migrating neurons by acting as a GO signal in lower layers and as a STOP signal in upper cortical plate (CP), respectively. Metabotropic GABAB receptors promote radial migration into the CP and tangential migration of interneurons. Besides GABA, the endogenous GABAergic agonist …
The aristaless (Arx) gene: one gene for many "interneuronopathies".
2009
The ARX (Aristaless-related (X-linked) homeobox) gene is not only present in arthropods and their ancestors, but also in vertebrates including humans (ARX orthologs). The gene is composed of 5 coding exons and it is expressed predominantly in foetal and adult brain and skeletal muscle. In this review we report on our experience and review the existing literature on the genotype and phenotype heterogeneity associated with ARX abnormalities in humans ranging from severe neuronal migration defects (e.g., lissencephaly), to mild forms of X-linked mental retardation without apparent brain abnormalities. The ARX-related disorders are reviewed focusing on their clinical features and on the role of…
A vascular perspective on neuronal migration
2015
During CNS development and adult neurogenesis, immature neurons travel from the germinal zones towards their final destination using cellular substrates for their migration. Classically, radial glia and neuronal axons have been shown to act as physical scaffolds to support neuroblast locomotion in processes known as gliophilic and neurophilic migration, respectively (Hatten, 1999; Marin and Rubenstein, 2003; Rakic, 2003). In adulthood, long distance neuronal migration occurs in a glial-independent manner since radial glia cells differentiate into astrocytes after birth. A series of studies highlight a novel mode of neuronal migration that uses blood vessels as scaffolds, the so-called vasop…
Dynamic Changes in Ultrastructure of the Primary Cilium in Migrating Neuroblasts in the Postnatal Brain
2019
New neurons, referred to as neuroblasts, are continuously generated in the ventricular-subventricular zone of the brain throughout an animal's life. These neuroblasts are characterized by their unique potential for proliferation, formation of chain-like cell aggregates, and long-distance and high-speed migration through the rostral migratory stream (RMS) toward the olfactory bulb (OB), where they decelerate and differentiate into mature interneurons. The dynamic changes of ultrastructural features in postnatal-born neuroblasts during migration are not yet fully understood. Here we report the presence of a primary cilium, and its ultrastructural morphology and spatiotemporal dynamics, in mig…
A role for the peroxisomal 3-ketoacyl-CoA thiolase B enzyme in the control of PPARα-mediated upregulation of SREBP-2 target genes in the liver.: ThB …
2011
International audience; Peroxisomal 3-ketoacyl-CoA thiolase B (Thb) catalyzes the final step in the peroxisomal β-oxidation of straight-chain acyl-CoAs and is under the transcription control of the nuclear hormone receptor PPARα. PPARα binds to and is activated by the synthetic compound Wy14,643 (Wy). Here, we show that the magnitude of Wy-mediated induction of peroxisomal β-oxidation of radiolabeled (1-(14)C) palmitate was significantly reduced in mice deficient for Thb. In contrast, mitochondrial β-oxidation was unaltered in Thb(-/-) mice. Given that Wy-treatment induced Acox1 and MFP-1/-2 activity at a similar level in both genotypes, we concluded that the thiolase step alone was respons…
Changes in the expression of cation-Cl- cotransporters, NKCC1 and KCC2, during cortical malformation induced by neonatal freeze-lesion.
2007
Focal cortical malformations comprise a heterogeneous group of disturbances in brain development, often associated with intractable epilepsy. A focal freeze-lesion of cerebral cortex in newborn rat produces a cortical malformation that resembles human polymicrogyria, clinical conditions that results from abnormal neuronal migration. The change in GABAergic functions that occurs during early brain development is induced by an alteration in Cl(-) homeostasis and plays important roles in neocortical development by modulating such events as laminar organization and synaptogenesis. We therefore investigated the relationship between pathogenesis of polymicrogyria and ontogeny of Cl(-) homeostasis…