Dab2IP Regulates Neuronal Positioning, Rap1 Activity and Integrin Signaling in the Developing Cortex

Shuhong Qiao; Ramin Homayouni

doi:10.1159/000369092

Dab2IP Regulates Neuronal Positioning, Rap1 Activity and Integrin Signaling in the Developing Cortex

Developmental Neuroscience ◽

10.1159/000369092 ◽

2015 ◽

Vol 37 (2) ◽

pp. 131-141 ◽

Cited By ~ 7

Author(s):

Shuhong Qiao ◽

Ramin Homayouni

Keyword(s):

Brain Development ◽

Cortical Neurons ◽

Ventricular Zone ◽

Physiological Role ◽

Immunohistochemical Analysis ◽

Superficial Layer ◽

Tumor Formation ◽

Intermediate Zone ◽

Cortical Plate ◽

Integrin Signaling

Dab2IP (DOC-2/DAB2 interacting protein) is a GTPase-activating protein which is involved in various aspects of brain development in addition to its roles in tumor formation and apoptosis in other systems. In this study, we carefully examined the expression profile of Dab2IP and investigated its physiological role during brain development using a Dab2IP-knockdown (KD) mouse model created by retroviral insertion of a LacZ-encoding gene-trapping cassette. LacZ staining revealed that Dab2IP is expressed in the ventricular zone as well as the cortical plate and the intermediate zone. Immunohistochemical analysis showed that Dab2IP protein is localized in the leading process and proximal cytoplasmic regions of migrating neurons in the intermediate zone. Bromodeoxyuridine birth dating experiments in combination with immunohistochemical analysis using layer-specific markers showed that Dab2IP is important for proper positioning of a subset of layer II-IV neurons in the developing cortex. Notably, neuronal migration was not completely disrupted in the cerebral cortex of Dab2IP-KD mice and disruption of migration was not strictly layer specific. Previously, we found that Dab2IP regulates multipolar transition in cortical neurons. Others have shown that Rap1 regulates the transition from multipolar to bipolar morphology in migrating postmitotic neurons through N-cadherin signaling and somal translocation in the superficial layer of the cortical plate through integrin signaling. Therefore, we examined whether Rap1 and integrin signaling were affected in Dab2IP-KD brains. We found that Dab2IP-KD resulted in higher levels of activated Rap1 and integrin in the developing cortex. Taken together, our results suggest that Dab2IP plays an important role in the migration and positioning of a subpopulation of later-born (layers II-IV) neurons, likely through the regulation of Rap1 and integrin signaling.

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Cellular migration patterns in the developing mouse cerebral cortex

Development ◽

10.1242/dev.110.3.713 ◽

1990 ◽

Vol 110 (3) ◽

pp. 713-732 ◽

Cited By ~ 1

Author(s):

C.P. Austin ◽

C.L. Cepko

Keyword(s):

Cortical Neurons ◽

Intermediate Zone ◽

Cellular Migration ◽

Three Dimensions ◽

Cortical Plate ◽

Cortical Cells ◽

Migration Patterns ◽

Embryonic Mouse ◽

Radial Migration ◽

Almost All

The migration patterns of embryonic mouse cortical cells were investigated using a replication-incompetent retrovirus vector (BAG). The lateral ventricles of embryonic day 12 mouse embryos were infected with BAG and brains were harvested 2, 3, 4 and 6 days after infection. The location and morphology of all infected cortical cells were recorded from serial sections of entire brains, which were then reconstructed in three dimensions. Examination of the distribution of labelled cells revealed that there were migration patterns characteristic of each medial-lateral domain of the cortex. In the medial and dorsal areas, migration was often radial, although tangential spread increased with survival time, in large part due to ramification of cells in the intermediate zone. In the dorsolateral and lateral areas of the cortex, radial migration was generally not observed. Rather, variable extents of tangential migration occurred, and often resulted in wide separation of cells in the cortical plate. Almost all of the cellular dispersion occurred in the intermediate zone, although a modest degree of dispersion also occurred within the cortical plate itself. Most dispersion occurred in the mediolateral plane, with relatively little dispersion along the anteroposterior axis. Though characteristic migration patterns could be defined, wide variability in the extents of radial migration and tangential separation of cells was seen. The patterns of migration paralleled the distribution of radial glial fibers in all areas, and are most likely a reflection of the role of this network in supporting the migration of cortical neurons. The extent and variability of cellular dispersion supports a lineage-independent mechanism of cortical column ontogenesis.

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Physiological Significance of WDR45, A Responsible Gene for β-propeller Protein Associated Neurodegeneration (BPAN), in Brain Development

10.21203/rs.3.rs-132972/v1 ◽

2020 ◽

Author(s):

Mariko Noda ◽

Hidenori Ito ◽

Koh-ichi Nagata

Keyword(s):

Brain Development ◽

Mouse Brain ◽

Cortical Neurons ◽

De Novo ◽

Early Stage ◽

Physiological Role ◽

Global Developmental Delay ◽

Dependent Manner ◽

Biochemical Fractionation ◽

Biochemical Analyses

Abstract WDR45 plays an essential role in the early stage of autophagy. De novo heterozygous mutations in WDR45 have been known to cause b-propeller protein-associated neurodegeneration (BPAN), a subtype of neurodegeneration with brain iron accumulation (NBIA). Although BPAN patients display global developmental delay including intellectual disability, neurodevelopmental pathophysiology of BPAN remains largely unknown. In the present study, we analyzed the physiological role of Wdr45 and pathophysiological significance of the gene abnormality during mouse brain development. Morphological and biochemical analyses revealed that Wdr45 is expressed in a developmental stage-dependent manner in mouse brain. Wdr45 was also found to be located in the excitatory synapses in biochemical fractionation. Since the WDR45 mutations are thought to cause protein degradation, we conducted acute knockdown experiments by an in utero electroporation method with mice to recapitulate the pathophysiological conditions of BPAN. Silencing of Wdr45 caused abnormal dendritic development and synaptogenesis during corticogenesis, both of which were significantly rescued by co-expression with RNAi-resistant version of Wdr45. In addition, terminal arbors of callosal axons were less developed in Wdr45-deficient cortical neurons of adult mouse when compared to the control cells. These results strongly suggest a pathophysiological significance of WDR45 gene abnormalities in neurodevelopmental aspects of BPAN.

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Changing Properties of GABAA Receptor–Mediated Signaling During Early Neocortical Development

Journal of Neurophysiology ◽

10.1152/jn.1999.82.2.570 ◽

1999 ◽

Vol 82 (2) ◽

pp. 570-583 ◽

Cited By ~ 120

Author(s):

David F. Owens ◽

Xiaolin Liu ◽

Arnold R. Kriegstein

Keyword(s):

Action Potential ◽

Cortical Neurons ◽

Ventricular Zone ◽

Receptor Activation ◽

Brain Regions ◽

Functional Change ◽

Precursor Cells ◽

Synaptic Activity ◽

Cortical Plate ◽

Early Maturation

Evidence from several brain regions suggests γ-aminobutyric acid (GABA) can exert a trophic influence during development, expanding the role of this amino acid beyond its function as an inhibitory neurotransmitter. Proliferating precursor cells in the neocortical ventricular zone (VZ) express functional GABAA receptors as do immature postmigratory neurons in the developing cortical plate (CP); however, GABAA receptor properties in these distinct cell populations have not been compared. Using electrophysiological techniques in embryonic and early postnatal neocortex, we find that GABAA receptors expressed by VZ cells have a higher apparent affinity for GABA and are relatively insensitive to receptor desensitization compared with neurons in the CP. GABA-induced current magnitude increases with maturation with the smallest responses found in recordings from precursor cells in the VZ. No evidence was found that GABAA receptors on VZ cells are activated synaptically, consistent with previous data suggesting that these receptors are activated in a paracrine fashion by nonsynaptically released ligand. After neurons are born and migrate to the CP, they begin to demonstrate spontaneous synaptic activity, the majority of which is GABAA mediated. These spontaneous GABAA postsynaptic currents (sPSCs) first were detected at embryonic day 18 (E18). At birth, ∼50% of recordings from cortical neurons demonstrated GABAA-mediated sPSCs, and this value increased with age. GABAA-mediated sPSCs were action potential dependent and arose from local GABAergic interneurons. GABA application could evoke action potential–dependent PSCs in neonatal cortical neurons, suggesting that during the first few postnatal days, GABA can act as an excitatory neurotransmitter. Finally, N-methyl-d-aspartate (NMDA)- but not non-NMDA-mediated sPSCs were also present in early postnatal neurons. These events were not observed in cells voltage clamped at negative holding potentials (−60 to −70 mV) but were evident when the holding potential was set at positive values (+30 to +60 mV). Together these results provide evidence for the early maturation of GABAergic communication in the neocortex and a functional change in GABAA-receptor properties between precursor cells and early postmitotic neurons. The change in GABAA-receptor properties may reflect the shift from paracrine to synaptic receptor activation.

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Cortical upper layer neurons derive from the subventricular zone as indicated bySvet1gene expression

Development ◽

10.1242/dev.128.11.1983 ◽

2001 ◽

Vol 128 (11) ◽

pp. 1983-1993 ◽

Cited By ~ 8

Author(s):

Victor Tarabykin ◽

Anastassia Stoykova ◽

Natalia Usman ◽

Peter Gruss

Keyword(s):

Cerebral Cortex ◽

Molecular Markers ◽

Cortical Neurons ◽

Ventricular Zone ◽

Underlying Mechanism ◽

Cdna Libraries ◽

Cortical Plate ◽

Cortical Layers ◽

Proliferating Cells ◽

Expression Domain

The cerebral cortex is composed of a large variety of different neuron types. All cortical neurons, except some interneurons, are born in two proliferative zones, the cortical ventricular (VZ) and subventricular (SVZ) zones. The relative contribution of both proliferative zones to the generation of the diversity of the cortical neurons is not well understood. To further dissect the underlying mechanism, molecular markers specific for the SVZ are required. Towards this end we performed a subtraction of cDNA libraries, generated from E15.5 and E18.5 mouse cerebral cortex. A novel cDNA, Svet1, was cloned which was specifically expressed in the proliferating cells of the SVZ but not the VZ. The VZ is marked by the expression of the Otx1 gene. Later in development, Svet1 and Otx1 were expressed in subsets of cells of upper (II-IV) and deep (V-VI) layers, respectively. In the reeler cortex, where the layers are inverted, Svet1 and Otx1 label precursors of the upper and deeper layers, respectively, in their new location. Interestingly, in the Pax6/small eye mutant, Svet1 activity was abolished in the SVZ and in the upper part of the cortical plate while the Otx1 expression domain remained unchanged. Therefore, using Svet1 and Otx1 as cell-type-specific molecular markers for the upper and deep cortical layers we conclude that the Sey mutation affects predominantly the differentiation of the SVZ cells that fail to migrate into the cortical plate. The abnormality of the SVZ coincides with the absence of upper layer cells in the cortex. Taken together our data suggest that while the specification of deep cortical layers occurs in the ventricular zone, the SVZ is important for the proper specification of upper layers.

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Physiological significance of WDR45, a responsible gene for β-propeller protein associated neurodegeneration (BPAN), in brain development

Scientific Reports ◽

10.1038/s41598-021-02123-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mariko Noda ◽

Hidenori Ito ◽

Koh-ichi Nagata

Keyword(s):

Brain Development ◽

Mouse Brain ◽

Cortical Neurons ◽

De Novo ◽

Early Stage ◽

Physiological Role ◽

Global Developmental Delay ◽

Dependent Manner ◽

Biochemical Fractionation ◽

Biochemical Analyses

AbstractWDR45 plays an essential role in the early stage of autophagy. De novo heterozygous mutations in WDR45 have been known to cause β-propeller protein-associated neurodegeneration (BPAN), a subtype of neurodegeneration with brain iron accumulation (NBIA). Although BPAN patients display global developmental delay with intellectual disability, the neurodevelopmental pathophysiology of BPAN remains largely unknown. In the present study, we analyzed the physiological role of Wdr45 and pathophysiological significance of the gene abnormality during mouse brain development. Morphological and biochemical analyses revealed that Wdr45 is expressed in a developmental stage-dependent manner in mouse brain. Wdr45 was also found to be located in excitatory synapses by biochemical fractionation. Since WDR45 mutations are thought to cause protein degradation, we conducted acute knockdown experiments by in utero electroporation in mice to recapitulate the pathophysiological conditions of BPAN. Knockdown of Wdr45 caused abnormal dendritic development and synaptogenesis during corticogenesis, both of which were significantly rescued by co-expression with RNAi-resistant version of Wdr45. In addition, terminal arbors of callosal axons were less developed in Wdr45-deficient cortical neurons of adult mouse when compared to control cells. These results strongly suggest a pathophysiological significance of WDR45 gene abnormalities in neurodevelopmental aspects of BPAN.

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Overexpression of Lin28A in neural progenitor cells in vivo does not lead to brain tumor formation but results in reduced spine density

Acta Neuropathologica Communications ◽

10.1186/s40478-021-01289-1 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Maximilian Middelkamp ◽

Lisa Ruck ◽

Christoph Krisp ◽

Piotr Sumisławski ◽

Behnam Mohammadi ◽

...

Keyword(s):

Brain Tumor ◽

Brain Tumors ◽

Brain Development ◽

Radial Glia ◽

Ventricular Zone ◽

Tumor Formation ◽

Microtubule Dynamics ◽

Dendrite Morphology ◽

Spine Morphogenesis

AbstractLIN28A overexpression has been identified in malignant brain tumors called embryonal tumors with multilayered rosettes (ETMR) but its specific role during brain development remains largely unknown. Radial glia cells of the ventricular zone (VZ) are proposed as a cell of origin for ETMR. We asked whether an overexpression of LIN28A in such cells might affect brain development or result in the formation of brain tumors.Constitutive overexpression of LIN28A in hGFAP-cre::lsl-Lin28A (GL) mice led to a transient increase of proliferation in the cortical VZ at embryonic stages but no postnatal brain tumor formation. Postnatally, GL mice displayed a pyramidal cell layer dispersion of the hippocampus and altered spine and dendrite morphology, including reduced dendritic spine densities in the hippocampus and cortex. GL mice displayed hyperkinetic activity and differential quantitative MS-based proteomics revealed altered time dependent molecular functions regarding mRNA processing and spine morphogenesis. Phosphoproteomic analyses indicated a downregulation of mTOR pathway modulated proteins such as Map1b being involved in microtubule dynamics.In conclusion, we show that Lin28A overexpression transiently increases proliferation of neural precursor cells but it is not sufficient to drive brain tumors in vivo. In contrast, Lin28A impacts on protein abundancy patterns related to spine morphogenesis and phosphorylation levels of proteins involved in microtubule dynamics, resulting in decreased spine densities of neurons in the hippocampus and cortex as well as in altered behavior. Our work provides new insights into the role of LIN28A for neuronal morphogenesis and development and may reveal future targets for treatment of ETMR patients.

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Involvement of Netrins and Their Receptors in Neuronal Migration in the Cerebral Cortex

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2020.590009 ◽

2021 ◽

Vol 8 ◽

Author(s):

Satoru Yamagishi ◽

Yuki Bando ◽

Kohji Sato

Keyword(s):

Neuronal Migration ◽

Cortical Neurons ◽

Intracellular Signaling ◽

Ventricular Zone ◽

Genetic Disorders ◽

Cortical Plate ◽

Ganglionic Eminence ◽

Deleted In Colorectal Cancer ◽

Guidance Molecules ◽

Extracellular Molecules

In mammals, excitatory cortical neurons develop from the proliferative epithelium and progenitor cells in the ventricular zone and subventricular zone, and migrate radially to the cortical plate, whereas inhibitory GABAergic interneurons are born in the ganglionic eminence and migrate tangentially. The migration of newly born cortical neurons is tightly regulated by both extracellular and intracellular signaling to ensure proper positioning and projections. Non-cell-autonomous extracellular molecules, such as growth factors, axon guidance molecules, extracellular matrix, and other ligands, play a role in cortical migration, either by acting as attractants or repellents. In this article, we review the guidance molecules that act as cell–cell recognition molecules for the regulation of neuronal migration, with a focus on netrin family proteins, their receptors, and related molecules, including neogenin, repulsive guidance molecules (RGMs), Down syndrome cell adhesion molecule (DSCAM), fibronectin leucine-rich repeat transmembrane proteins (FLRTs), and draxin. Netrin proteins induce attractive and repulsive signals depending on their receptors. For example, binding of netrin-1 to deleted in colorectal cancer (DCC), possibly together with Unc5, repels migrating GABAergic neurons from the ventricular zone of the ganglionic eminence, whereas binding to α3β1 integrin promotes cortical interneuron migration. Human genetic disorders associated with these and related guidance molecules, such as congenital mirror movements, schizophrenia, and bipolar disorder, are also discussed.

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An absence of lamin B1 in migrating neurons causes nuclear membrane ruptures and cell death

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1917225116 ◽

2019 ◽

Vol 116 (51) ◽

pp. 25870-25879 ◽

Cited By ~ 11

Author(s):

Natalie Y. Chen ◽

Ye Yang ◽

Thomas A. Weston ◽

Jason N. Belling ◽

Patrick Heizer ◽

...

Keyword(s):

Dna Damage ◽

Cell Death ◽

Nuclear Membrane ◽

Neuronal Migration ◽

Cortical Neurons ◽

Nuclear Translocation ◽

Neuronal Survival ◽

Ventricular Zone ◽

Cortical Plate ◽

Lamin B1

Deficiencies in either lamin B1 or lamin B2 cause both defective migration of cortical neurons in the developing brain and reduced neuronal survival. The neuronal migration abnormality is explained by a weakened nuclear lamina that interferes with nucleokinesis, a nuclear translocation process required for neuronal migration. In contrast, the explanation for impaired neuronal survival is poorly understood. We hypothesized that the forces imparted on the nucleus during neuronal migration result in nuclear membrane (NM) ruptures, causing interspersion of nuclear and cytoplasmic contents—and ultimately cell death. To test this hypothesis, we bredLmnb1-deficient mice that express a nuclear-localized fluorescentCrereporter. Migrating neurons within the cortical plate of E18.5Lmnb1-deficient embryos exhibited NM ruptures, evident by the escape of the nuclear-localized reporter into the cytoplasm and NM discontinuities by electron microscopy. The NM ruptures were accompanied by DNA damage and cell death. The NM ruptures were not observed in nonmigrating cells within the ventricular zone. NM ruptures, DNA damage, and cell death were also observed in culturedLmnb1−/−andLmnb2−/−neurons as they migrated away from neurospheres. To test whether mechanical forces on the cell nucleus are relevant to NM ruptures in migrating neurons, we examined culturedLmnb1−/−neurons when exposed to external constrictive forces (migration into a field of tightly spaced silicon pillars). As the cells entered the field of pillars, there were frequent NM ruptures, accompanied by DNA damage and cell death.

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Biochemical and Morphological Characterization of a Neurodevelopmental Disorder-Related Mono-ADP-Ribosylhydrolase, MACRO Domain Containing 2

Developmental Neuroscience ◽

10.1159/000492271 ◽

2018 ◽

Vol 40 (3) ◽

pp. 278-287 ◽

Cited By ~ 8

Author(s):

Hidenori Ito ◽

Rika Morishita ◽

Makoto Mizuno ◽

Noriko Kawamura ◽

Hidenori Tabata ◽

...

Keyword(s):

Brain Development ◽

Cortical Neurons ◽

Hippocampal Neurons ◽

Neurodevelopmental Disorder ◽

Physiological Role ◽

Morphological Characterization ◽

Molecular Features ◽

Synaptic Markers ◽

Macro Domain ◽

Molecular Masses

MACRO Domain Containing 2 (MacroD2) is a neurodevelopmental disorder-related mono-ADP-ribosylhydrolase. Molecular features of this protein in neural tissues are largely unknown. In this study, we generated a specific antibody against MacroD2, and carried out expression and morphological analyses of the molecule during mouse brain development. In Western blotting, 2 MacroD2 isoforms with molecular masses of ∼70 and ∼75 kDa started to be expressed at embryonic day 16.5, reached the maximal level at postnatal day 8, and then gradually decreased through P30. In contrast, other isoforms with molecular masses of ∼110 and ∼140 kDa gradually increased during embryonic to postnatal development. In immunohistochemical analyses, MacroD2 was strongly detected in cortical neurons in layer II–V at P0 and P7, while the protein expression decreased significantly in the neurons at P30. Immunofluorescence analyses revealed that MacroD2 was mainly distributed in the soma and to a lesser extent in the axon and dendrite of immature primary cultured mouse hippocampal neurons. On the other hand, in the matured hippocampal neurons, while MacroD2 was detected in the soma, it displayed in dendrites a punctate distribution pattern with a partial colocalization with synaptic markers, synaptophysin, and PSD95. The obtained results indicate that MacroD2 is expressed and may have a physiological role in the central nervous system during brain development.

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