1
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Dab1-deficient deep layer neurons prevent Dab1-deficient superficial layer neurons from entering the cortical plate. Neurosci Res 2022; 180:23-35. [DOI: 10.1016/j.neures.2022.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 02/06/2023]
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2
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Shin M, Kitazawa A, Yoshinaga S, Hayashi K, Hirata Y, Dehay C, Kubo K, Nakajima K. Both excitatory and inhibitory neurons transiently form clusters at the outermost region of the developing mammalian cerebral neocortex. J Comp Neurol 2019; 527:1577-1597. [PMID: 30636008 DOI: 10.1002/cne.24634] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 12/20/2018] [Accepted: 01/08/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Minkyung Shin
- Department of AnatomyKeio University School of Medicine Tokyo Japan
| | - Ayako Kitazawa
- Department of AnatomyKeio University School of Medicine Tokyo Japan
| | | | - Kanehiro Hayashi
- Department of AnatomyKeio University School of Medicine Tokyo Japan
| | - Yukio Hirata
- Department of AnatomyKeio University School of Medicine Tokyo Japan
| | - Colette Dehay
- Inserm, Stem Cell and Brain Research Institute U1208Université de Lyon, Université Claude Bernard Lyon 1 Bron France
| | - Ken‐ichiro Kubo
- Department of AnatomyKeio University School of Medicine Tokyo Japan
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3
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Oishi K, Nakajima K. Subtype Specification of Cerebral Cortical Neurons in Their Immature Stages. Neurochem Res 2017; 43:238-244. [PMID: 29185180 DOI: 10.1007/s11064-017-2441-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 11/21/2017] [Accepted: 11/23/2017] [Indexed: 10/18/2022]
Abstract
The diversification of neuronal subtypes during corticogenesis is fundamental to the establishment of the complex cortical structure. Although subtype specification has been assumed to occur in neural progenitor cells, increasing evidence has begun to reveal the plasticity of subtype determination in immature neurons. Here, we summarize recent findings regarding the regulation of subtype specification during later periods of neuronal differentiation, such as the post-mitotic and post-migratory stages. We also discuss thalamocortical axons as an extra-cortical cue that provides information on the subtype determination of immature cortical neurons.
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Affiliation(s)
- Koji Oishi
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
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4
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Hirota Y, Nakajima K. Control of Neuronal Migration and Aggregation by Reelin Signaling in the Developing Cerebral Cortex. Front Cell Dev Biol 2017; 5:40. [PMID: 28507985 PMCID: PMC5410752 DOI: 10.3389/fcell.2017.00040] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/31/2017] [Indexed: 11/13/2022] Open
Abstract
The mammalian cerebral neocortex has a well-organized laminar structure, achieved by the highly coordinated control of neuronal migration. During cortical development, excitatory neurons born near the lateral ventricle migrate radially to reach their final positions to form the cortical plate. During this process, dynamic changes are observed in the morphologies and migration modes, including multipolar migration, locomotion, and terminal translocation, of the newborn neurons. Disruption of these migration processes can result in neuronal disorders such as lissencephaly and periventricular heterotopia. The extracellular protein, Reelin, mainly secreted by the Cajal-Retzius neurons in the marginal zone during development, plays a crucial role in the neuronal migration and neocortical lamination. Reelin signaling, which exerts essential roles in the formation of the layered neocortex, is triggered by the binding of Reelin to its receptors, ApoER2 and VLDLR, followed by phosphorylation of the Dab1 adaptor protein. Accumulating evidence suggests that Reelin signaling controls multiple steps of neuronal migration, including the transition from multipolar to bipolar neurons, terminal translocation, and termination of migration beneath the marginal zone. In addition, it has been shown that ectopically expressed Reelin can cause neuronal aggregation via an N-cadherin-mediated manner. This review attempts to summarize our knowledge of the roles played by Reelin in neuronal migration and the underlying mechanisms.
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Affiliation(s)
- Yuki Hirota
- Department of Anatomy, Keio University School of MedicineTokyo, Japan
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of MedicineTokyo, Japan
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5
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Reelin transiently promotes N-cadherin-dependent neuronal adhesion during mouse cortical development. Proc Natl Acad Sci U S A 2017; 114:2048-2053. [PMID: 28174271 DOI: 10.1073/pnas.1615215114] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Reelin is an essential glycoprotein for the establishment of the highly organized six-layered structure of neurons of the mammalian neocortex. Although the role of Reelin in the control of neuronal migration has been extensively studied at the molecular level, the mechanisms underlying Reelin-dependent neuronal layer organization are not yet fully understood. In this study, we directly showed that Reelin promotes adhesion among dissociated neocortical neurons in culture. The Reelin-mediated neuronal aggregation occurs in an N-cadherin-dependent manner, both in vivo and in vitro. Unexpectedly, however, in a rotation culture of dissociated neocortical cells that gradually reaggregated over time, we found that it was the neural progenitor cells [radial glial cells (RGCs)], rather than the neurons, that tended to form clusters in the presence of Reelin. Mathematical modeling suggested that this clustering of RGCs could be recapitulated if the Reelin-dependent promotion of neuronal adhesion were to occur only transiently. Thus, we directly measured the adhesive force between neurons and N-cadherin by atomic force microscopy, and found that Reelin indeed enhanced the adhesiveness of neurons to N-cadherin; this enhanced adhesiveness began to be observed at 30 min after Reelin stimulation, but declined by 3 h. These results suggest that Reelin transiently (and not persistently) promotes N-cadherin-mediated neuronal aggregation. When N-cadherin and stabilized β-catenin were overexpressed in the migrating neurons, the transfected neurons were abnormally distributed in the superficial region of the neocortex, suggesting that appropriate regulation of N-cadherin-mediated adhesion is important for correct positioning of the neurons during neocortical development.
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6
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Mutually repressive interaction between Brn1/2 and Rorb contributes to the establishment of neocortical layer 2/3 and layer 4. Proc Natl Acad Sci U S A 2016; 113:3371-6. [PMID: 26951672 DOI: 10.1073/pnas.1515949113] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Although several molecules have been shown to play important roles in subtype specification of neocortical neurons, the entire mechanism involved in the specification, in particular, of upper cortical plate (UCP) neurons still remains unclear. The UCP, which is responsible for intracortical connections in the neocortex, comprises histologically, functionally, and molecularly different layer 2/3 (L2/3) and L4. Here, we report the essential interactions between two types of transcription factors, Rorb (RAR-related orphan receptor beta) and Brn1/2 (Brain-1/Brain-2), for UCP specification. We found that Brn2 expression was detected in all upper layers in the immature UCP, but was subsequently restricted to L2/3, accompanied by up-regulation of Rorb in L4, suggesting demarcation of L2/3 and L4 during cortical maturation. Rorb indeed inhibited Brn2 expression and the expression of other L2/3 characteristics, revealed by ectopic expression and knockdown studies. Moreover, this inhibition occurred through direct binding of Rorb to the Brn2 locus. Conversely, Brn1/2 also inhibited Rorb expression and the expression of several L4 characteristics. Together, these results suggest that a mutually repressive mechanism exists between Brn1/2 and Rorb expression and that the established expression of Brn1/2 and Rorb further specifies those neurons into L2/3 and L4, respectively, during UCP maturation.
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7
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Oishi K, Nakagawa N, Tachikawa K, Sasaki S, Aramaki M, Hirano S, Yamamoto N, Yoshimura Y, Nakajima K. Identity of neocortical layer 4 neurons is specified through correct positioning into the cortex. eLife 2016; 5. [PMID: 26880563 PMCID: PMC4764574 DOI: 10.7554/elife.10907] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/28/2016] [Indexed: 11/13/2022] Open
Abstract
Many cell-intrinsic mechanisms have been shown to regulate neuronal subtype specification in the mammalian neocortex. However, how much cell environment is crucial for subtype determination still remained unclear. Here, we show that knockdown of Protocadherin20 (Pcdh20), which is expressed in post-migratory neurons of layer 4 (L4) lineage, caused the cells to localize in L2/3. The ectopically positioned "future L4 neurons" lost their L4 characteristics but acquired L2/3 characteristics. Knockdown of a cytoskeletal protein in the future L4 neurons, which caused random disruption of positioning, also showed that those accidentally located in L4 acquired the L4 characteristics. Moreover, restoration of positioning of the Pcdh20-knockdown neurons into L4 rescued the specification failure. We further suggest that the thalamocortical axons provide a positional cue to specify L4 identity. These results suggest that the L4 identity is not completely determined at the time of birth but ensured by the surrounding environment after appropriate positioning.
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Affiliation(s)
- Koji Oishi
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
| | - Nao Nakagawa
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes for Natural Sciences, Okazaki, Japan.,Department of Physiological Sciences, Graduate University for Advanced Studies, Okazaki, Japan
| | - Kashiko Tachikawa
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
| | - Shinji Sasaki
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
| | - Michihiko Aramaki
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
| | - Shinji Hirano
- Department of Cell Biology, Kansai Medical University, Osaka, Japan
| | - Nobuhiko Yamamoto
- Laboratory of Cellular and Molecular Neurobiology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yumiko Yoshimura
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes for Natural Sciences, Okazaki, Japan.,Department of Physiological Sciences, Graduate University for Advanced Studies, Okazaki, Japan
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
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8
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Hayashi K, Kubo KI, Kitazawa A, Nakajima K. Cellular dynamics of neuronal migration in the hippocampus. Front Neurosci 2015; 9:135. [PMID: 25964735 PMCID: PMC4408843 DOI: 10.3389/fnins.2015.00135] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/02/2015] [Indexed: 12/30/2022] Open
Abstract
A fine structure of the hippocampus is required for proper functions, and disruption of this formation by neuronal migration defects during development may play a role in some psychiatric illnesses. During hippocampal development in rodents, pyramidal neurons in the Ammon's horn are mostly generated in the ventricular zone (VZ), spent as multipolar cells just above the VZ, and then migrate radially toward the pial surface, ultimately settling into the hippocampal plate. Although this process is similar to that of neocortical projection neurons, these are not identical. In addition to numerous histological studies, the development of novel techniques gives a clear picture of the cellular dynamics of hippocampal neurons, as well as neocortical neurons. In this article, we provide an overview of the cellular mechanisms of rodent hippocampal neuronal migration including those of dentate granule cells, especially focusing on the differences of migration modes between hippocampal neurons and neocortical neurons. The unique migration mode of hippocampal pyramidal neurons might enable clonally related cells in the Ammon's horn to distribute in a horizontal fashion.
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Affiliation(s)
- Kanehiro Hayashi
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
| | - Ken-Ichiro Kubo
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
| | - Ayako Kitazawa
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
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9
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How does Reelin control neuronal migration and layer formation in the developing mammalian neocortex? Neurosci Res 2014; 86:50-8. [PMID: 24969097 DOI: 10.1016/j.neures.2014.06.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/25/2014] [Accepted: 05/29/2014] [Indexed: 01/08/2023]
Abstract
The mammalian neocortex has a laminar structure that develops in a birth-date-dependent "inside-out" pattern. Its layered structure is established by neuronal migration accompanied by sequential changes in migratory mode regulated by several signaling cascades. Although Reelin was discovered about two decades ago and is one of the best known molecules that is indispensable to the establishment of the "inside-out" neuron layers, the cellular and molecular functions of Reelin in layer formation are still largely unknown. In this review article, we summarize our recent understanding of Reelin's functions during neuronal migration. Reelin acts in at least two different steps of neuronal migration: the final step of neuronal migration (somal/terminal translocation) just beneath the marginal zone (MZ) and the regulation of cell polarity step when the neurons change their migratory mode from multipolar migration to locomotion. During the translocation mode, Reelin activates integrin α5β1 through an intracellular pathway that triggers the translocation and activates N-cadherin in concert with the nectin-afadin system. Reelin is also involved in the termination of neuronal migration by degrading Dab1 via the SOCS7-Cullin5-Rbx2 system, and Reelin has been found to induce the birth-date-dependent neuronal aggregation in vivo. Based on these findings, we hypothesize that the molecular function of Reelin during neuronal migration is to control cell-adhesiveness during development by regulating the expression/activation of cell adhesion molecules.
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10
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Karus M, Blaess S, Brüstle O. Self-organization of neural tissue architectures from pluripotent stem cells. J Comp Neurol 2014; 522:2831-44. [PMID: 24737617 DOI: 10.1002/cne.23608] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 04/09/2014] [Accepted: 04/09/2014] [Indexed: 12/23/2022]
Abstract
Despite being a subject of intensive research, the mechanisms underlying the formation of neural tissue architectures during development of the central nervous system remain largely enigmatic. So far, studies into neural pattern formation have been restricted mainly to animal experiments. With the advent of pluripotent stem cells it has become possible to explore early steps of nervous system development in vitro. These studies have unraveled a remarkable propensity of primitive neural cells to self-organize into primitive patterns such as neural tube-like rosettes in vitro. Data from more advanced 3D culture systems indicate that this intrinsic propensity for self-organization can even extend to the formation of complex architectures such as a multilayered cortical neuroepithelium or an entire optic cup. These novel experimental paradigms not only demonstrate the enormous self-organization capacity of neural stem cells, they also provide exciting prospects for studying the earliest steps of human neural tissue development and the pathogenesis of brain malformations in reductionist in vitro paradigms.
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Affiliation(s)
- Michael Karus
- Institute of Reconstructive Neurobiology, University of Bonn LIFE&BRAIN Center, and LIFE&BRAIN GmbH, 53127, Bonn, Germany
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11
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Gonda Y, Andrews WD, Tabata H, Namba T, Parnavelas JG, Nakajima K, Kohsaka S, Hanashima C, Uchino S. Robo1 regulates the migration and laminar distribution of upper-layer pyramidal neurons of the cerebral cortex. Cereb Cortex 2013; 23:1495-508. [PMID: 22661412 PMCID: PMC3643720 DOI: 10.1093/cercor/bhs141] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Laminar organization is a key feature of the mammalian cerebral cortex, but the mechanisms by which final positioning and "inside-out" distribution of neurons are determined remain largely unknown. Here, we demonstrate that Robo1, a member of the family of Roundabout receptors, regulates the correct positioning of layers II/III pyramidal neurons in the neocortex. Specifically, we used RNA interference in mice to suppress the expression of Robo1 in a subset of layers II/III neurons, and observed the positions of these cells at distinct developmental stages. In contrast to control neurons that migrated toward the pial surface by P1, Robo1-suppressed neurons exhibited a delay in entering the cortical plate at respective stages. Unexpectedly, after the first postnatal week, these neurons were predominantly located in the upper part of layers II/III, in contrast to control cells that were distributed throughout these layers. Sequential electroporation studies revealed that Robo1-suppressed cells failed to establish the characteristic inside-out neuronal distribution and, instead, they accumulated beneath the marginal zone regardless of their birthdate. These results demonstrate that Robo receptors play a crucial role in neocortical lamination and particularly in the positioning of layers II/III pyramidal neurons.
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Affiliation(s)
- Yuko Gonda
- Laboratory for Neocortical Development, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
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12
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Oshikawa M, Okada K, Nakajima K, Ajioka I. Cortical excitatory neurons become protected from cell division during neurogenesis in an Rb family-dependent manner. Development 2013; 140:2310-20. [PMID: 23615279 DOI: 10.1242/dev.095653] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell cycle dysregulation leads to abnormal proliferation and cell death in a context-specific manner. Cell cycle progression driven via the Rb pathway forces neurons to undergo S-phase, resulting in cell death associated with the progression of neuronal degeneration. Nevertheless, some Rb- and Rb family (Rb, p107 and p130)-deficient differentiating neurons can proliferate and form tumors. Here, we found in mouse that differentiating cerebral cortical excitatory neurons underwent S-phase progression but not cell division after acute Rb family inactivation in differentiating neurons. However, the differentiating neurons underwent cell division and proliferated when Rb family members were inactivated in cortical progenitors. Differentiating neurons generated from Rb(-/-); p107(-/-); p130(-/-) (Rb-TKO) progenitors, but not acutely inactivated Rb-TKO differentiating neurons, activated the DNA double-strand break (DSB) repair pathway without increasing trimethylation at lysine 20 of histone H4 (H4K20), which has a role in protection against DNA damage. The activation of the DSB repair pathway was essential for the cell division of Rb-TKO differentiating neurons. These results suggest that newly born cortical neurons from progenitors become epigenetically protected from DNA damage and cell division in an Rb family-dependent manner.
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Affiliation(s)
- Mio Oshikawa
- Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
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13
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Thalamus-derived molecules promote survival and dendritic growth of developing cortical neurons. J Neurosci 2013; 32:15388-402. [PMID: 23115177 DOI: 10.1523/jneurosci.0293-12.2012] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The mammalian neocortex is composed of various types of neurons that reflect its laminar and area structures. It has been suggested that not only intrinsic but also afferent-derived extrinsic factors are involved in neuronal differentiation during development. However, the role and molecular mechanism of such extrinsic factors are almost unknown. Here, we attempted to identify molecules that are expressed in the thalamus and affect cortical cell development. First, thalamus-specific molecules were sought by comparing gene expression profiles of the developing rat thalamus and cortex using microarrays, and by constructing a thalamus-enriched subtraction cDNA library. A systematic screening by in situ hybridization showed that several genes encoding extracellular molecules were strongly expressed in sensory thalamic nuclei. Exogenous and endogenous protein localization further demonstrated that two extracellular molecules, Neuritin-1 (NRN1) and VGF, were transported to thalamic axon terminals. Application of NRN1 and VGF to dissociated cell culture promoted the dendritic growth. An organotypic slice culture experiment further showed that the number of primary dendrites in multipolar stellate neurons increased in response to NRN1 and VGF, whereas dendritic growth of pyramidal neurons was not promoted. These molecules also increased neuronal survival of multipolar neurons. Taken together, these results suggest that the thalamus-specific molecules NRN1 and VGF play an important role in the dendritic growth and survival of cortical neurons in a cell type-specific manner.
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14
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A phosphatidylinositol lipids system, lamellipodin, and Ena/VASP regulate dynamic morphology of multipolar migrating cells in the developing cerebral cortex. J Neurosci 2012; 32:11643-56. [PMID: 22915108 DOI: 10.1523/jneurosci.0738-12.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the developing mammalian cerebral cortex, excitatory neurons are generated in the ventricular zone (VZ) and subventricular zone; these neurons migrate toward the pial surface. The neurons generated in the VZ assume a multipolar morphology and remain in a narrow region called the multipolar cell accumulation zone (MAZ) for ∼24 h, in which they extend and retract multiple processes dynamically. They eventually extend an axon tangentially and begin radial migration using a migratory mode called locomotion. Despite the potential biological importance of the process movement of multipolar cells, the molecular mechanisms remain to be elucidated. Here, we observed that the processes of mouse multipolar cells were actin rich and morphologically resembled the filopodia and lamellipodia in growth cones; thus, we focused on the actin-remodeling proteins Lamellipodin (Lpd) and Ena/vasodilator-stimulated phosphoprotein (VASP). Lpd binds to phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P₂] and recruits Ena/VASP, which promotes the assembly of actin filaments, to the plasma membranes. In situ hybridization and immunohistochemistry revealed that Lpd is expressed in multipolar cells in the MAZ. The functional silencing of either Lpd or Ena/VASP decreased the number of primary processes. Immunostaining and a Förster resonance energy transfer analysis revealed the subcellular localization of PI(3,4)P₂ at the tips of the processes. A knockdown experiment and treatment with an inhibitor for Src homology 2-containing inositol phosphatase-2, a 5-phosphatase that produces PI(3,4)P₂ from phosphatidylinositol (3,4,5)-triphosphate, decreased the number of primary processes. Our observations suggest that PI(3,4)P₂, Lpd, and Ena/VASP are involved in the process movement of multipolar migrating cells.
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15
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Lee WC, Berry R, Hohenstein P, Davies J. siRNA as a tool for investigating organogenesis: The pitfalls and the promises. Organogenesis 2012; 4:176-81. [PMID: 19279730 DOI: 10.4161/org.4.3.6642] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 03/20/2008] [Indexed: 12/31/2022] Open
Abstract
Removing the function of a specific gene from a developing organ, by making a 'knockout' mouse, is a powerful method for analyzing the molecular pathways that control organogenesis. The technique is expensive, though, in terms of time and money, and complex strategies for producing conditional knockouts are needed for genes that are essential for early development of the embryo, for which an unconditional knockout would be lethal before the organ of interest begins to form. Small interfering RNAs (siRNAs) offer a method of knocking down the expression of specific genes with no need for genomic manipulation. Almost as soon as they had been discovered, siRNAs began to be used to explore the molecular biology of mammalian cells in conventional, two-dimensional culture. They have now also been applied successfully, by several groups, to knock down specific genes in various organ rudiments developing in organ culture. This article reviews the basic technique of siRNA-mediated gene knockdown and how it is being applied to organ culture. It also reviews some of the current problems and challenges in the field, and the ways in which these problems are likely to be overcome.
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Affiliation(s)
- Wen-Chin Lee
- Centre for Integrative Physiology; University of Edinburgh; Edinburgh UK
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16
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Lin JY. Optogenetic excitation of neurons with channelrhodopsins: light instrumentation, expression systems, and channelrhodopsin variants. PROGRESS IN BRAIN RESEARCH 2012; 196:29-47. [PMID: 22341319 DOI: 10.1016/b978-0-444-59426-6.00002-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Classically, temporally precise excitation of membrane potential in neurons within intact tissue can be achieved by direct electrical stimulation or indirect electrical stimulation induced by changing magnetic fields. Both of these approaches have a predetermined selectivity based on the biophysical properties of the nervous tissue and membrane in the region of the stimulation. A recent advance in selective excitation of neurons is the "optogenetic" approach utilizing channelrhodopsins (ChRs). By expressing the light-responsive ChR in neurons using cell-type selective promoters or other methods, specific neurons can be depolarized by light in a temporally precise manner with millisecond resolution even if their membrane biophysical properties are less favorable for electrical stimulation. In addition, ChRs can be used to depolarize nonneuronal cells in the nervous tissue, and to sustain depolarization over a prolonged period of time, both of which cannot be achieved with electrical or magnetic stimulations. To conduct an experiment with ChR, experimenters need to make the correct choices on the three main components to such an experiment: the expression system, the illumination source, and the ChR variant used. This chapter aims to provide some discussions on the current developments of these aspects of the experiments. To express ChR in neurons, the common expression systems include viral vectors, in utero electroporation, and transgenic animals, each with their advantages and limitations regarding the cost, expression pattern, and the required effort. In terms of the instrumentation, an illumination source that is capable of providing the desired wavelength with high intensity is crucial for the success of the experiment. The important factors regarding the light source used include the cost, light density output, efficiency for fiber coupling for in vivo rodent experiments, and the available methods to control light intensity and onset/termination. The third component of the experiment is the choice of the appropriate variants of ChR. Many novel ChR variants with unique properties have been engineered, and it can be difficult for the experimenters to choose the right variant with the desired properties for their experiments, as some information necessary for the experimenter to make the right selection is often incomplete or unavailable. Currently, the available variants for neuroscientific research are wild-type ChR2, ChR2+H134R, ChETA, VChR1, SFO, ChD, ChEF, ChIEF, ChRGR, CatCh, and TC. The features and limitations of these different variants are presented here. Lastly, this chapter will provide some suggestion for the future development of the light source, expression system, and the development of the "next" generation of ChRs.
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Affiliation(s)
- John Y Lin
- Department of Pharmacology, University of California at San Diego, La Jolla, CA, USA.
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17
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The outermost region of the developing cortical plate is crucial for both the switch of the radial migration mode and the Dab1-dependent "inside-out" lamination in the neocortex. J Neurosci 2011; 31:9426-39. [PMID: 21697392 DOI: 10.1523/jneurosci.0650-11.2011] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mammalian neocortex has a laminated structure that develops in a birth-date-dependent "inside-out" pattern. This layered structure is established by neuronal migration with sequential changes of the migratory mode regulated by several signaling cascades, including the Reelin-Disabled homolog 1 (Dab1) pathway. Although the importance of "locomotion," the major migratory mode, has been well established, the physiological significance of the mode change from locomotion to "terminal translocation," the final migratory mode, is unknown. In this study, we found that the outermost region of the mouse cortical plate has several histologically distinct features and named this region the primitive cortical zone (PCZ). Time-lapse analyses revealed that "locomoting" neurons paused transiently just beneath the PCZ before migrating into it by "terminal translocation." Furthermore, whereas Dab1-knockdown (KD) neurons could reach beneath the PCZ, they failed to enter the PCZ, suggesting that the Dab1-dependent terminal translocation is necessary for entry of the neurons into the PCZ. Importantly, sequential in utero electroporation experiments directly revealed that failure of the Dab1-dependent terminal translocation resulted in disruption of the inside-out alignment within the PCZ and that this disrupted pattern was still preserved in the mature cortex. Conversely, Dab1-KD locomoting neurons could pass by both wild-type and Dab1-KD predecessors beneath the PCZ. Our data indicate that the PCZ is a unique environment, passage of neurons through which involves molecularly and behaviorally different migratory mechanisms, and that the migratory mode change from locomotion to terminal translocation just beneath the PCZ is critical for the Dab1-dependent inside-out lamination in the mature cortex.
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18
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Transcriptional programs in transient embryonic zones of the cerebral cortex defined by high-resolution mRNA sequencing. Proc Natl Acad Sci U S A 2011; 108:14950-5. [PMID: 21873192 DOI: 10.1073/pnas.1112213108] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Characterizing the genetic programs that specify development and evolution of the cerebral cortex is a central challenge in neuroscience. Stem cells in the transient embryonic ventricular and subventricular zones generate neurons that migrate across the intermediate zone to the overlying cortical plate, where they differentiate and form the neocortex. It is clear that not one but a multitude of molecular pathways are necessary to progress through each cellular milestone, yet the underlying transcriptional programs remain unknown. Here, we apply differential transcriptome analysis on microscopically isolated cell populations, to define five transcriptional programs that represent each transient embryonic zone and the progression between these zones. The five transcriptional programs contain largely uncharacterized genes in addition to transcripts necessary for stem cell maintenance, neurogenesis, migration, and differentiation. Additionally, we found intergenic transcriptionally active regions that possibly encode unique zone-specific transcripts. Finally, we present a high-resolution transcriptome map of transient zones in the embryonic mouse forebrain.
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Takemoto M, Hattori Y, Zhao H, Sato H, Tamada A, Sasaki S, Nakajima K, Yamamoto N. Laminar and areal expression of unc5d and its role in cortical cell survival. ACTA ACUST UNITED AC 2011; 21:1925-34. [PMID: 21216843 DOI: 10.1093/cercor/bhq265] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The UNC-5 family of netrin receptors is known to regulate axon guidance, cell migration, and cell survival. We have previously demonstrated that unc5d, one of the UNC-5 family member genes, is specifically expressed in layer 4 of the developing rat neocortex (Zhong Y, Takemoto M, Fukuda T, Hattori Y, Murakami F, Nakajima D, Nakayama M, Yamamoto N. 2004. Identification of the genes that are expressed in the upper layers of the neocortex. Cereb Cortex. 14:1144-1152). However, the role of UNC5D in cortical development is still unknown. In this study, we revealed that unc5d was highly expressed in the primary sensory areas of the mouse neocortex at around postnatal day 7. Netrin-4 was also found to be predominantly expressed in layer 4 of the sensory cortex and sensory thalamic nuclei. Cell surface binding assay showed that netrin-4 protein bound to UNC5D-expressing cells. An in vitro study further demonstrated that cell death of unc5d-expressing layer 4 cells was reduced by exogenous application of netrin-4 protein, whereas UNC5D is not sufficient to mediate the effect of netrin-4 in deep layer cells. Taken together, these results suggest that UNC5D is primarily expressed by layer 4 cells in the primary sensory areas of the developing neocortex and may mediate the effect of netrin-4 on cortical cell survival in a lamina-specific manner.
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Affiliation(s)
- Makoto Takemoto
- Division of Cellular and Molecular Neurobiology, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
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20
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Ectopic Reelin induces neuronal aggregation with a normal birthdate-dependent "inside-out" alignment in the developing neocortex. J Neurosci 2010; 30:10953-66. [PMID: 20720102 DOI: 10.1523/jneurosci.0486-10.2010] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Neurons in the developing mammalian neocortex form the cortical plate (CP) in an "inside-out" manner; that is, earlier-born neurons form the deeper layers, whereas later-born neurons migrate past the existing layers and form the more superficial layers. Reelin, a glycoprotein secreted by Cajal-Retzius neurons in the marginal zone (MZ), is crucial for this "inside-out" layering, because the layers are inverted in the Reelin-deficient mouse, reeler (Reln(rl)). Even though more than a decade has passed since the discovery of reelin, the biological effect of Reelin on individual migrating neurons remains unclear. In addition, although the MZ is missing in the reeler cortex, it is unknown whether Reelin directly regulates the development of the cell-body-sparse MZ. To address these issues, we expressed Reelin ectopically in the developing mouse cortex, and the results showed that Reelin caused the leading processes of migrating neurons to assemble in the Reelin-rich region, which in turn induced their cell bodies to form cellular aggregates around Reelin. Interestingly, the ectopic Reelin-rich region became cell-body-sparse and dendrite-rich, resembling the MZ, and the late-born neurons migrated past their predecessors toward the central Reelin-rich region within the aggregates, resulting in a birthdate-dependent "inside-out" alignment even ectopically. Reelin receptors and intracellular adaptor protein Dab1 were found to be necessary for formation of the aggregates. The above findings indicate that Reelin signaling is capable of inducing the formation of the dendrite-rich, cell-body-sparse MZ and a birthdate-dependent "inside-out" alignment of neurons independently of other factors/structures near the MZ.
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Dekimoto H, Terashima T, Katsuyama Y. Dispersion of the neurons expressing layer specific markers in the reeler brain. Dev Growth Differ 2010; 52:181-93. [PMID: 20067496 DOI: 10.1111/j.1440-169x.2009.01153.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neurons with similar functions including neuronal connectivity and gene expression form discrete condensed structures within the vertebrate brain. This is exemplified within the circuitry formed by the cortical layers and the neuronal nuclei. It is well known that the Reelin protein is required for development of these neuronal structures in rodents and human, but the function of Reelin remains controversial. In this report, we used "layer-specific markers" of the cerebral cortex to carry out detailed observations of spatial distribution of the neuronal subpopulations in the brain of the Reelin deficient mouse, reeler. We observed a spatially dispersed expression of the markers in the reeler cerebral cortex. These markers are expressed also in other laminated and non-laminated structures of brain, in which we observed similar abnormal gene expression. Our observations suggest that neurons within the brain structures (such as the layers and the nuclei), which normally exhibit condensed distribution of marker expressions, loosen their segregation or scatter by a lack of Reelin.
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Affiliation(s)
- Hideyuki Dekimoto
- Division of Anatomy and Neurobiology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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22
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Eiraku M, Watanabe K, Matsuo-Takasaki M, Kawada M, Yonemura S, Matsumura M, Wataya T, Nishiyama A, Muguruma K, Sasai Y. Self-organized formation of polarized cortical tissues from ESCs and its active manipulation by extrinsic signals. Cell Stem Cell 2009; 3:519-32. [PMID: 18983967 DOI: 10.1016/j.stem.2008.09.002] [Citation(s) in RCA: 1023] [Impact Index Per Article: 68.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 09/06/2008] [Accepted: 09/09/2008] [Indexed: 11/17/2022]
Abstract
Here, we demonstrate self-organized formation of apico-basally polarized cortical tissues from ESCs using an efficient three-dimensional aggregation culture (SFEBq culture). The generated cortical neurons are functional, transplantable, and capable of forming proper long-range connections in vivo and in vitro. The regional identity of the generated pallial tissues can be selectively controlled (into olfactory bulb, rostral and caudal cortices, hem, and choroid plexus) by secreted patterning factors such as Fgf, Wnt, and BMP. In addition, the in vivo-mimicking birth order of distinct cortical neurons permits the selective generation of particular layer-specific neurons by timed induction of cell-cycle exit. Importantly, cortical tissues generated from mouse and human ESCs form a self-organized structure that includes four distinct zones (ventricular, early and late cortical-plate, and Cajal-Retzius cell zones) along the apico-basal direction. Thus, spatial and temporal aspects of early corticogenesis are recapitulated and can be manipulated in this ESC culture.
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Affiliation(s)
- Mototsugu Eiraku
- Organogenesis and Neurogenesis Group, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
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23
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Tachikawa K, Sasaki S, Maeda T, Nakajima K. Identification of molecules preferentially expressed beneath the marginal zone in the developing cerebral cortex. Neurosci Res 2007; 60:135-46. [PMID: 18055048 DOI: 10.1016/j.neures.2007.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 10/03/2007] [Accepted: 10/10/2007] [Indexed: 12/17/2022]
Abstract
During cerebral cortical development, the majority of excitatory neurons are born near the ventricle and migrate radially toward the marginal zone (MZ). Since the cells invariably stop migrating beneath the MZ, neurons are aligned in an "inside-out" manner in the cortical plate (CP); that is, the early-born and late-born neurons are ultimately positioned in the deep and superficial layers, respectively. Since dramatic morphological changes occur in cells beneath the MZ, several events critical for proper neuronal maturation and layer formation must take place. In this study, we screened for molecules strongly expressed beneath the MZ, and identified 28 genes that are preferentially expressed in the upper half of the mouse CP on both embryonic day (E) 16.5 and E18.5. Expression analyses in reeler and yotari mice, in which neurons terminate migration throughout the CP, suggested that these genes were indeed related to the events beneath the MZ rather than unrelatedly induced by the structures near the brain surface. Pathway analyses suggested calcium signaling to have an important role in cells beneath the MZ. The gene list presented here will be useful for clarifying the molecular mechanisms that control cortical development.
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Affiliation(s)
- Kashiko Tachikawa
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Maeda TT, Ajioka I, Nakajima K. Computational cell model based on autonomous cell movement regulated by cell-cell signalling successfully recapitulates the "inside and outside" pattern of cell sorting. BMC SYSTEMS BIOLOGY 2007; 1:43. [PMID: 17883828 PMCID: PMC2100066 DOI: 10.1186/1752-0509-1-43] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Accepted: 09/20/2007] [Indexed: 11/10/2022]
Abstract
BACKGROUND Development of multicellular organisms proceeds from a single fertilized egg as the combined effect of countless numbers of cellular interactions among highly dynamic cells. Since at least a reminiscent pattern of morphogenesis can be recapitulated in a reproducible manner in reaggregation cultures of dissociated embryonic cells, which is known as cell sorting, the cells themselves must possess some autonomous cell behaviors that assure specific and reproducible self-organization. Understanding of this self-organized dynamics of heterogeneous cell population seems to require some novel approaches so that the approaches bridge a gap between molecular events and morphogenesis in developmental and cell biology. A conceptual cell model in a computer may answer that purpose. We constructed a dynamical cell model based on autonomous cell behaviors, including cell shape, growth, division, adhesion, transformation, and motility as well as cell-cell signaling. The model gives some insights about what cellular behaviors make an appropriate global pattern of the cell population. RESULTS We applied the model to "inside and outside" pattern of cell-sorting, in which two different embryonic cell types within a randomly mixed aggregate are sorted so that one cell type tends to gather in the central region of the aggregate and the other cell type surrounds the first cell type. Our model can modify the above cell behaviors by varying parameters related to them. We explored various parameter sets with which the "inside and outside" pattern could be achieved. The simulation results suggested that direction of cell movement responding to its neighborhood and the cell's mobility are important for this specific rearrangement. CONCLUSION We constructed an in silico cell model that mimics autonomous cell behaviors and applied it to cell sorting, which is a simple and appropriate phenomenon exhibiting self-organization of cell population. The model could predict directional cell movement and its mobility are important in the "inside and outside" pattern of cell sorting. Those behaviors are altered by signal molecules and consequently affect the global pattern of the cell sorting. Our model is also applicable to other developmental processes beyond cell sorting.
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Affiliation(s)
- Takuya T Maeda
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Computational and Experimental Systems Biology Group, RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Japan
| | - Itsuki Ajioka
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332N Lauderdale, Memphis, TN 38105, USA
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Molecular Neurobiology, Institute of DNA Medicine, Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
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Nakajima K. Control of tangential/non-radial migration of neurons in the developing cerebral cortex. Neurochem Int 2007; 51:121-31. [PMID: 17588709 DOI: 10.1016/j.neuint.2007.05.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 05/15/2007] [Accepted: 05/17/2007] [Indexed: 01/23/2023]
Abstract
Projection neurons in the developing cerebral cortex of rodents are basically born near the ventricle and migrate radially to beneath the marginal zone, whereas their cortical interneurons are generated in the ventral telencephalon and migrate tangentially to the cortex. The origins and migratory profiles of each interneuron subtype have been studied extensively in the last decade, and an enormous effort has been made to clarify the cellular and molecular mechanisms that regulate interneuron migration. More recently, the interaction between projection neurons and migrating interneurons, including how they are incorporated into their proper layers, has begun to be analyzed. In this review, I outline the most recent findings in regard to these issues and discuss the mechanisms underlying the development of cortical cytoarchitecture.
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Affiliation(s)
- Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan.
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26
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Gonda Y, Sakurai H, Hirata Y, Tabata H, Ajioka I, Nakajima K. Expression profiles of Insulin-like growth factor binding protein-like 1 in the developing mouse forebrain. Gene Expr Patterns 2006; 7:431-40. [PMID: 17175204 DOI: 10.1016/j.modgep.2006.11.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 10/18/2006] [Accepted: 11/09/2006] [Indexed: 11/18/2022]
Abstract
Insulin-like growth factor binding protein-like 1 (IGFBPL-1) has a domain structure that resembles one in the insulin-like growth factor binding proteins (IGFBPs), which is a domain known to be bound by insulin-like growth factors (IGFs) with high affinity and to thereby affect cell growth and metabolism. However, the distribution and functions of IGFBPL-1 in the brain are not known. Thus, to clarify IGFBPL-1 expression profiles during development, we have investigated the expression patterns of IGFBPL-1 mRNA in developing mouse brains using in situ hybridization, focusing especially on the forebrain. On embryonic day (E)12, IGFBPL-1mRNA expressions were localized in the preplate of the neopallium, dorsal thalamus, the differentiating field of the epithalamus, and the hippocampus. On E14, strong expression was recognized in the subventricular zone (SVZ) and intermediate zone (IMZ) in the neopallium, hippocampus, the differentiating field of the epithalamus, and the dorsal thalamus. E14 expressions were generally the strongest among all the stages examined and signals decreased thereafter. At E16 and E18, IGFBPL-1mRNA was strongly detected in the hippocampus and the SVZ of the neopallium. In postnatal stages, mRNA was found only in the granule cell layer of the dentate gyrus (DG). Notably, at P20, expression was restricted to the deep fraction of the granule cell layer, the location of late-born DG neurons.
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Affiliation(s)
- Yuko Gonda
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Ajioka I, Maeda T, Nakajima K. Identification of ventricular-side-enriched molecules regulated in a stage-dependent manner during cerebral cortical development. Eur J Neurosci 2006; 23:296-308. [PMID: 16420439 DOI: 10.1111/j.1460-9568.2005.04544.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Radial glial cells are the main component of the embryonic cortical ventricular zone (VZ), producing deep-layer excitatory neurons in the early stage and upper-layer excitatory neurons in the late stage of development. Previous studies have suggested that the laminar fate of deep-layer neurons might be determined by early-stage-specific secretory or transmembrane molecules (S/TMs) in the VZ. However, the different properties required to produce the different types of neurons in early-stage and late-stage VZ cells are largely unknown. Herein, we investigated the stage-dependent transcriptional profiles of the ventricular side of the mouse cortex, which was manually dissected at embryonic day (E)12, E14 and E16, and identified 3985 'VZ-enriched' genes, regulated stage-dependently, by GeneChip analysis. These molecules were classified into nine types based on stage-dependent regulation patterns. Prediction programs for the S/TMs revealed 659 'VZ-enriched' S/TMs. In situ hybridization and real-time PCR analysis for several of these molecules showed results consistent with the statistical analysis of the GeneChip experiments. Moreover, we identified 17 cell cycle-related early-stage and 'VZ-enriched' molecules. These molecules included not only those involved in cell cycle progression, but also essential molecules for DNA double-strand break repair, such as Rad51 and Rpa1. These results suggest that the early stage-VZ cells, which produce both deep- and upper-layer neurons, and the late-stage VZ cells, which produce only upper-layer neurons, are intrinsically different. The gene lists presented here will be useful for the investigation of stage-dependent changes in VZ cells and their regulatory mechanisms in the developing cortex.
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Affiliation(s)
- Itsuki Ajioka
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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28
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Ajioka I, Nakajima K. Switching of alpha-catenin from alphaE-catenin in the cortical ventricular zone to alphaN-catenin II in the intermediate zone. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 160:106-11. [PMID: 16185771 DOI: 10.1016/j.devbrainres.2005.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 08/05/2005] [Accepted: 08/07/2005] [Indexed: 10/25/2022]
Abstract
Although cadherins and catenins are known to play important roles during neural development, the types of alpha-catenin present in the developing telencephalon are still unknown. Here, we show that the ventricular zones (VZ) of the cortex and the ganglionic eminences express alphaE-catenin and alphaN-catenin, respectively, in a complementary manner. In the cortex, alpha-catenin is switched from alphaE-catenin in the VZ to alphaN-catenin II in the intermediate zone (IMZ).
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Affiliation(s)
- Itsuki Ajioka
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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