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Yang Y, Li S, Luo L. Responses of organ precursors to correct and incorrect inductive signals. Trends Cell Biol 2024; 34:484-495. [PMID: 37739814 DOI: 10.1016/j.tcb.2023.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/14/2023] [Accepted: 08/31/2023] [Indexed: 09/24/2023]
Abstract
During embryonic development, the inductive molecules produced by local origins normally arrive at their target tissues in a nondirectional, diffusion manner. The target organ precursor cells must correctly interpret these inductive signals to ensure proper specification/differentiation, which is dependent on two prerequisites: (i) obtaining cell-intrinsic competence; and (ii) receiving correct inductive signals while resisting incorrect ones. Gain of intrinsic competence could avoid a large number of misinductions because the incompetent cells are nonresponsive to inductive signals. However, in cases of different precursor cells with similar competence and located in close proximity, resistance to incorrect inductive signals is essential for accurate determination of cell fate. Here we outline the mechanisms of how organ precursors respond to correct and incorrect inductive signals.
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Affiliation(s)
- Yun Yang
- Institute of Development Biology and Regenerative Medicine, Southwest University, Chongqing, China
| | - Shuang Li
- Institute of Development Biology and Regenerative Medicine, Southwest University, Chongqing, China
| | - Lingfei Luo
- Institute of Development Biology and Regenerative Medicine, Southwest University, Chongqing, China; School of Life Sciences, Fudan University, Shanghai, China.
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2
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Mabry SA, Pavon N. Exploring the prospects, advancements, and challenges of in vitro modeling of the heart-brain axis. Front Cell Neurosci 2024; 18:1386355. [PMID: 38766369 PMCID: PMC11099243 DOI: 10.3389/fncel.2024.1386355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/12/2024] [Indexed: 05/22/2024] Open
Abstract
Research on bidirectional communication between the heart and brain has often relied on studies involving nonhuman animals. Dependance on animal models offer limited applicability to humans and a lack of high-throughput screening. Recently, the field of 3D cell biology, specifically organoid technology, has rapidly emerged as a valuable tool for studying interactions across organ systems, i.e., gut-brain axis. The initial success of organoid models indicates the usefulness of 3D cultures for elucidating the intricate interactivity of the autonomic nervous system and overall health. This perspective aims to explore the potential of advancing in vitro modeling of the heart-brain axis by discussing the benefits, applications, and adaptability of organoid technologies. We closely examine the current state of brain organoids in conjunction with the advancements of cardiac organoids. Moreover, we explore the use of combined organoid systems to investigate pathophysiology and provide a platform for treatment discovery. Finally, we address the challenges that accompany the use of 3D models for studying the heart-brain axis with an emphasis on generating tailored engineering strategies for further refinement of dynamic organ system modeling in vitro.
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Affiliation(s)
- Senegal Alfred Mabry
- Affect and Cognition Laboratory, Department of Psychology and Human Development, College of Human Ecology, Cornell University, Ithaca, NY, United States
| | - Narciso Pavon
- ChangHui Pak Laboratory, Department of Biochemistry and Molecular Biology, College of Natural Sciences, University of Massachusetts-Amherst, Amherst, MA, United States
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3
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Wang CY, Zuo Z, Kim KI, Bellen HJ, Lee HK. CK2α-dependent regulation of Wnt activity governs white matter development and repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536369. [PMID: 37090554 PMCID: PMC10120613 DOI: 10.1101/2023.04.11.536369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Wnt signaling plays an essential role in developmental and regenerative myelination in the CNS. The Wnt signaling pathway is comprised of multiple regulatory layers; thus, how these processes are coordinated to orchestrate oligodendrocyte development remains unclear. Here we show CK2α, a Wnt/β-catenin signaling Ser/Thr kinase, phosphorylates Daam2, inhibiting its function and Wnt-activity during oligodendrocyte development. Intriguingly, we found Daam2 phosphorylation differentially impacts distinct stages of oligodendrocyte development, accelerating early differentiation followed by decelerating maturation and myelination. Application towards white matter injury revealed CK2α-mediated Daam2 phosphorylation plays a protective role for developmental and behavioral recovery after neonatal hypoxia, while promoting myelin repair following adult demyelination. Together, our findings identify a novel regulatory node in the Wnt pathway that regulates oligodendrocyte development via protein phosphorylation-induced signaling complex instability and highlights a new biological mechanism for myelin restoration. Significance Wnt signaling plays a vital role in OL development and has been implicated as an adverse event for myelin repair after white matter injury. Emerging studies have shed light on multi-modal roles of Wnt effectors in the OL lineage, but the underlying molecular mechanisms and modifiable targets in OL remyelination remain unclear. Using genetic mouse development and injury model systems, we delineate a novel stage-specific function of Daam2 in Wnt signaling and OL development via a S704/T7-5 phosphorylation mechanism, and determine a new role of the kinase CK2α in contributing to OL development. In-depth understanding of CK2α-Daam2 pathway regulation will allow us to precisely modulate its activity in conjunction with Wnt signaling and harness its biology for white matter pathology.
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4
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Gupta S, Butler SJ. Getting in touch with your senses: Mechanisms specifying sensory interneurons in the dorsal spinal cord. WIREs Mech Dis 2021; 13:e1520. [PMID: 34730293 PMCID: PMC8459260 DOI: 10.1002/wsbm.1520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 11/18/2022]
Abstract
The spinal cord is functionally and anatomically divided into ventrally derived motor circuits and dorsally derived somatosensory circuits. Sensory stimuli originating either at the periphery of the body, or internally, are relayed to the dorsal spinal cord where they are processed by distinct classes of sensory dorsal interneurons (dIs). dIs convey sensory information, such as pain, heat or itch, either to the brain, and/or to the motor circuits to initiate the appropriate response. They also regulate the intensity of sensory information and are the major target for the opioid analgesics. While the developmental mechanisms directing ventral and dorsal cell fates have been hypothesized to be similar, more recent research has suggested that dI fates are specified by novel mechanisms. In this review, we will discuss the molecular events that specify dorsal neuronal patterning in the spinal cord, thereby generating diverse dI identities. We will then discuss how this molecular understanding has led to the development of robust stem cell methods to derive multiple spinal cell types, including the dIs, and the implication of these studies for treating spinal cord injuries and neurodegenerative diseases. This article is categorized under: Neurological Diseases > Stem Cells and Development.
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Affiliation(s)
- Sandeep Gupta
- Department of NeurobiologyUniversity of California, Los AngelesLos AngelesCaliforniaUSA
| | - Samantha J. Butler
- Department of NeurobiologyUniversity of California, Los AngelesLos AngelesCaliforniaUSA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell ResearchUniversity of California, Los AngelesLos AngelesCaliforniaUSA
- Intellectual and Developmental Disabilities Research CenterUniversity of California, Los AngelesLos AngelesCaliforniaUSA
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5
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Repina NA, McClave T, Johnson HJ, Bao X, Kane RS, Schaffer DV. Engineered Illumination Devices for Optogenetic Control of Cellular Signaling Dynamics. Cell Rep 2021; 31:107737. [PMID: 32521262 PMCID: PMC9357365 DOI: 10.1016/j.celrep.2020.107737] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 03/09/2020] [Accepted: 05/14/2020] [Indexed: 10/31/2022] Open
Abstract
Spatially and temporally varying patterns of morphogen signals during development drive cell fate specification at the proper location and time. However, current in vitro methods typically do not allow for precise, dynamic spatiotemporal control of morphogen signaling and are thus insufficient to readily study how morphogen dynamics affect cell behavior. Here, we show that optogenetic Wnt/β-catenin pathway activation can be controlled at user-defined intensities, temporal sequences, and spatial patterns using engineered illumination devices for optogenetic photostimulation and light activation at variable amplitudes (LAVA). By patterning human embryonic stem cell (hESC) cultures with varying light intensities, LAVA devices enabled dose-responsive control of optoWnt activation and Brachyury expression. Furthermore, time-varying and spatially localized patterns of light revealed tissue patterning that models the embryonic presentation of Wnt signals in vitro. LAVA devices thus provide a low-cost, user-friendly method for high-throughput and spatiotemporal optogenetic control of cell signaling for applications in developmental and cell biology.
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Affiliation(s)
- Nicole A Repina
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA; Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, CA, USA; Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Thomas McClave
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Hunter J Johnson
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA; Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, CA, USA; Graduate Program in Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xiaoping Bao
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ravi S Kane
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - David V Schaffer
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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6
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Cutarelli A, Martínez-Rojas VA, Tata A, Battistella I, Rossi D, Arosio D, Musio C, Conti L. A Monolayer System for the Efficient Generation of Motor Neuron Progenitors and Functional Motor Neurons from Human Pluripotent Stem Cells. Cells 2021; 10:cells10051127. [PMID: 34066970 PMCID: PMC8151197 DOI: 10.3390/cells10051127] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/27/2021] [Accepted: 05/04/2021] [Indexed: 12/12/2022] Open
Abstract
Methods for the conversion of human induced pluripotent stem cells (hiPSCs) into motor neurons (MNs) have opened to the generation of patient-derived in vitro systems that can be exploited for MN disease modelling. However, the lack of simplified and consistent protocols and the fact that hiPSC-derived MNs are often functionally immature yet limit the opportunity to fully take advantage of this technology, especially in research aimed at revealing the disease phenotypes that are manifested in functionally mature cells. In this study, we present a robust, optimized monolayer procedure to rapidly convert hiPSCs into enriched populations of motor neuron progenitor cells (MNPCs) that can be further amplified to produce a large number of cells to cover many experimental needs. These MNPCs can be efficiently differentiated towards mature MNs exhibiting functional electrical and pharmacological neuronal properties. Finally, we report that MN cultures can be long-term maintained, thus offering the opportunity to study degenerative phenomena associated with pathologies involving MNs and their functional, networked activity. These results indicate that our optimized procedure enables the efficient and robust generation of large quantities of MNPCs and functional MNs, providing a valid tool for MNs disease modelling and for drug discovery applications.
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Affiliation(s)
- Alessandro Cutarelli
- Laboratory of Stem Cell Biology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, 38123 Trento, Italy; (A.C.); (A.T.); (I.B.)
| | - Vladimir A. Martínez-Rojas
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), 38123 Trento, Italy; (V.A.M.-R.); (D.A.); (C.M.)
| | - Alice Tata
- Laboratory of Stem Cell Biology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, 38123 Trento, Italy; (A.C.); (A.T.); (I.B.)
| | - Ingrid Battistella
- Laboratory of Stem Cell Biology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, 38123 Trento, Italy; (A.C.); (A.T.); (I.B.)
| | - Daniela Rossi
- Laboratory for Research on Neurodegenerative Disorders, Istituti Clinici Scientifici Maugeri IRCCS, 27100 Pavia, Italy;
| | - Daniele Arosio
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), 38123 Trento, Italy; (V.A.M.-R.); (D.A.); (C.M.)
| | - Carlo Musio
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), 38123 Trento, Italy; (V.A.M.-R.); (D.A.); (C.M.)
| | - Luciano Conti
- Laboratory of Stem Cell Biology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, 38123 Trento, Italy; (A.C.); (A.T.); (I.B.)
- Correspondence: ; Tel.: +39-0461-285216
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7
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Leung B, Shimeld SM. Evolution of vertebrate spinal cord patterning. Dev Dyn 2019; 248:1028-1043. [PMID: 31291046 DOI: 10.1002/dvdy.77] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/14/2019] [Accepted: 06/15/2019] [Indexed: 12/17/2022] Open
Abstract
The vertebrate spinal cord is organized across three developmental axes, anterior-posterior (AP), dorsal-ventral (DV), and medial-lateral (ML). Patterning of these axes is regulated by canonical intercellular signaling pathways: the AP axis by Wnt, fibroblast growth factor, and retinoic acid (RA), the DV axis by Hedgehog, Tgfβ, and Wnt, and the ML axis where proliferation is controlled by Notch. Developmental time plays an important role in which signal does what and when. Patterning across the three axes is not independent, but linked by interactions between signaling pathway components and their transcriptional targets. Combined this builds a sophisticated organ with many different types of cell in specific AP, DV, and ML positions. Two living lineages share phylum Chordata with vertebrates, amphioxus, and tunicates, while the jawless fish such as lampreys, survive as the most basally divergent vertebrate lineage. Genes and mechanisms shared between lampreys and other vertebrates tell us what predated vertebrates, while those also shared with other chordates tell us what evolved early in chordate evolution. Between these lie vertebrate innovations: genetic and developmental changes linked to evolution of new morphology. These include gene duplications, differences in how signals are received, and new regulatory connections between signaling pathways and their target genes.
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Affiliation(s)
- Brigid Leung
- Department of Zoology, University of Oxford, Oxford, UK
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8
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Wang C, Li J, Takemaru KI, Jiang X, Xu G, Wang B. Centrosomal protein Dzip1l binds Cby, promotes ciliary bud formation, and acts redundantly with Bromi to regulate ciliogenesis in the mouse. Development 2018; 145:dev.164236. [PMID: 29487109 DOI: 10.1242/dev.164236] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 02/16/2018] [Indexed: 12/14/2022]
Abstract
The primary cilium is a microtubule-based organelle required for Hedgehog (Hh) signaling and consists of a basal body, a ciliary axoneme and a compartment between the first two structures, called the transition zone (TZ). The TZ serves as a gatekeeper to control protein composition in cilia, but less is known about its role in ciliary bud formation. Here, we show that centrosomal protein Dzip1l is required for Hh signaling between Smoothened and Sufu. Dzip1l colocalizes with basal body appendage proteins and Rpgrip1l, a TZ protein. Loss of Dzip1l results in reduced ciliogenesis and dysmorphic cilia in vivo Dzip1l interacts with, and acts upstream of, Cby, an appendage protein, in ciliogenesis. Dzip1l also has overlapping functions with Bromi (Tbc1d32) in ciliogenesis, cilia morphogenesis and neural tube patterning. Loss of Dzip1l arrests ciliogenesis at the stage of ciliary bud formation from the TZ. Consistent with this, Dzip1l mutant cells fail to remove the capping protein Cp110 (Ccp110) from the distal end of mother centrioles and to recruit Rpgrip1l to the TZ. Therefore, Dzip1l promotes ciliary bud formation and is required for the integrity of the TZ.
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Affiliation(s)
- Chengbing Wang
- Department of Genetic Medicine, Weill Medical College of Cornell University, 1300 York Avenue, W404, New York, NY 10065, USA
| | - Jia Li
- Department of Genetic Medicine, Weill Medical College of Cornell University, 1300 York Avenue, W404, New York, NY 10065, USA
| | - Ken-Ichi Takemaru
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Xiaogang Jiang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, Jiangsu 215123, China
| | - Guoqiang Xu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, Jiangsu 215123, China
| | - Baolin Wang
- Department of Genetic Medicine, Weill Medical College of Cornell University, 1300 York Avenue, W404, New York, NY 10065, USA .,Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, W404, New York, NY 10065, USA
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9
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Key apoptotic genes APAF1 and CASP9 implicated in recurrent folate-resistant neural tube defects. Eur J Hum Genet 2018; 26:420-427. [PMID: 29358613 PMCID: PMC5838979 DOI: 10.1038/s41431-017-0025-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 09/29/2017] [Accepted: 10/10/2017] [Indexed: 12/25/2022] Open
Abstract
Neural tube defects (NTDs) remain one of the most serious birth defects, and although genes in several pathways have been implicated as risk factors for neural tube defects via knockout mouse models, very few molecular causes in humans have been identified. Whole exome sequencing identified deleterious variants in key apoptotic genes in two families with recurrent neural tube defects. Functional studies in fibroblasts indicate that these variants are loss-of-function, as apoptosis is significantly reduced. This is the first report of variants in apoptotic genes contributing to neural tube defect risk in humans.
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10
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Abstract
The ZIC2 transcription factor is one of the most commonly mutated genes in Holoprosencephaly (HPE) probands. HPE is a severe congenital defect of forebrain development which occurs when the cerebral hemispheres fail to separate during the early stages of organogenesis and is typically associated with mispatterning of the embryonic midline. Recent study of genotype-phenotype correlations in HPE cases has defined distinctive features of ZIC2-associated HPE presentation and genetics, revealing that ZIC2 mutation does not produce the craniofacial abnormalities generally thought to characterise HPE but leads to a range of non-forebrain phenotypes. Furthermore, the studies confirm the extent of ZIC2 allelic heterogeneity and that pathogenic variants of ZIC2 are associated with both classic and middle interhemispheric variant (MIHV) HPE which arise from defective ventral and dorsal forebrain patterning, respectively. An allelic series of mouse mutants has helped to delineate the cellular and molecular mechanisms by which one gene leads to defects in these related but distinct embryological processes.
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Affiliation(s)
- Kristen S Barratt
- Early Mammalian Development Laboratory, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Ruth M Arkell
- Early Mammalian Development Laboratory, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
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11
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Brafman D, Willert K. Wnt/β-catenin signaling during early vertebrate neural development. Dev Neurobiol 2017; 77:1239-1259. [PMID: 28799266 DOI: 10.1002/dneu.22517] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/24/2017] [Accepted: 08/09/2017] [Indexed: 12/29/2022]
Abstract
The vertebrate central nervous system (CNS) is comprised of vast number of distinct cell types arranged in a highly organized manner. This high degree of complexity is achieved by cellular communication, including direct cell-cell contact, cell-matrix interactions, and cell-growth factor signaling. Among the several developmental signals controlling the development of the CNS, Wnt proteins have emerged as particularly critical and, hence, have captivated the attention of many researchers. With Wnts' evolutionarily conserved function as primordial symmetry breaking signals, these proteins and their downstream effects are responsible for simultaneously establishing cellular diversity and tissue organization. With their expansive repertoire of secreted agonists and antagonists, cell surface receptors, signaling cascades and downstream biological effects, Wnts are ideally suited to control the complex processes underlying vertebrate neural development. In this review, we will describe the mechanisms by which Wnts exert their potent effects on cells and tissues and highlight the many roles of Wnt signaling during neural development, starting from the initial induction of the neural plate, the subsequent patterning along the embryonic axes, to the intricately organized structure of the CNS. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1239-1259, 2017.
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Affiliation(s)
- David Brafman
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, 85287
| | - Karl Willert
- Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, 92093-0695
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12
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Eckei G, Böing M, Brand-Saberi B, Morosan-Puopolo G. Expression Pattern of Axin2 During Chicken Development. PLoS One 2016; 11:e0163610. [PMID: 27680024 PMCID: PMC5040342 DOI: 10.1371/journal.pone.0163610] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 09/12/2016] [Indexed: 11/18/2022] Open
Abstract
Canonical Wnt-signalling is well understood and has been extensively described in many developmental processes. The regulation of this signalling pathway is of outstanding relevance for proper development of the vertebrate and invertebrate embryo. Axin2 provides a negative-feedback-loop in the canonical Wnt-pathway, being a target gene and a negative regulator. Here we provide a detailed analysis of the expression pattern in the development of the chicken embryo. By performing in-situ hybridization on chicken embryos from stage HH 04+ to HH 32 we detected a temporally and spatially restricted dynamic expression of Axin2. In particular, data about the expression of Axin2 mRNA in early embryogenesis, somites, neural tube, limbs, kidney and eyes was obtained.
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Affiliation(s)
- Gesa Eckei
- Department of Anatomy and Molecular Embryology, Ruhr-University of Bochum, Bochum, Germany
| | - Marion Böing
- Department of Anatomy and Molecular Embryology, Ruhr-University of Bochum, Bochum, Germany
| | - Beate Brand-Saberi
- Department of Anatomy and Molecular Embryology, Ruhr-University of Bochum, Bochum, Germany
| | - Gabriela Morosan-Puopolo
- Department of Anatomy and Molecular Embryology, Ruhr-University of Bochum, Bochum, Germany
- * E-mail:
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13
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Uygur A, Young J, Huycke TR, Koska M, Briscoe J, Tabin CJ. Scaling Pattern to Variations in Size during Development of the Vertebrate Neural Tube. Dev Cell 2016; 37:127-35. [PMID: 27093082 PMCID: PMC4854284 DOI: 10.1016/j.devcel.2016.03.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/29/2016] [Accepted: 03/23/2016] [Indexed: 11/06/2022]
Abstract
Anatomical proportions are robustly maintained in individuals that vary enormously in size, both within a species and between members of related taxa. However, the mechanisms underlying scaling are still poorly understood. We have examined this phenomenon in the context of the patterning of the ventral neural tube in response to a gradient of the morphogen Sonic hedgehog (SHH) in the chick and zebra finch, two species that differ in size during the time of neural tube patterning. We find that scaling is achieved, at least in part, by altering the sensitivity of the target cells to SHH and appears to be achieved by modulating the ratio of the repressive and activating transcriptional regulators, GLI2 and GLI3. This mechanism contrasts with previous experimental and theoretical analyses of morphogenic scaling that have focused on compensatory changes in the morphogen gradient itself.
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Affiliation(s)
- Aysu Uygur
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - John Young
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Tyler R Huycke
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Mervenaz Koska
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - James Briscoe
- Mill Hill Laboratory, The Francis Crick Institute, London NW7 1AA, UK
| | - Clifford J Tabin
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
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14
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Rockel JS, Yu C, Whetstone H, Craft AM, Reilly K, Ma H, Tsushima H, Puviindran V, Al-Jazrawe M, Keller GM, Alman BA. Hedgehog inhibits β-catenin activity in synovial joint development and osteoarthritis. J Clin Invest 2016; 126:1649-63. [PMID: 27018594 DOI: 10.1172/jci80205] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/11/2016] [Indexed: 12/21/2022] Open
Abstract
Both the WNT/β-catenin and hedgehog signaling pathways are important in the regulation of limb development, chondrocyte differentiation, and degeneration of articular cartilage in osteoarthritis (OA). It is not clear how these signaling pathways interact in interzone cell differentiation and synovial joint morphogenesis. Here, we determined that constitutive activation of hedgehog signaling specifically within interzone cells induces joint morphological changes by selectively inhibiting β-catenin-induced Fgf18 expression. Stabilization of β-catenin or treatment with FGF18 rescued hedgehog-induced phenotypes. Hedgehog signaling induced expression of a dominant negative isoform of TCF7L2 (dnTCF7L2) in interzone progeny, which may account for the selective regulation of β-catenin target genes observed. Knockdown of TCF7L2 isoforms in mouse chondrocytes rescued hedgehog signaling-induced Fgf18 downregulation, while overexpression of the human dnTCF7L2 orthologue (dnTCF4) in human chondrocytes promoted the expression of catabolic enzymes associated with OA. Similarly, expression of dnTCF4 in human chondrocytes positively correlated with the aggrecanase ADAMTS4. Consistent with our developmental findings, activation of β-catenin also attenuated hedgehog-induced or surgically induced articular cartilage degeneration in mouse models of OA. Thus, our results demonstrate that hedgehog inhibits selective β-catenin target gene expression to direct interzone progeny fates and articular cartilage development and disease. Moreover, agents that increase β-catenin activity have the potential to therapeutically attenuate articular cartilage degeneration as part of OA.
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15
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Wnt1 signal determines the patterning of the diencephalic dorso-ventral axis. Brain Struct Funct 2015; 221:3693-708. [PMID: 26452989 DOI: 10.1007/s00429-015-1126-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 09/30/2015] [Indexed: 12/31/2022]
Abstract
The diencephalon is a complex brain area that derives from the caudal region of the prosencephalon. This structure is divided into four longitudinal neuroepithelial zones: roof, alar, basal and floor plates, which constitute its dorso-ventral (DV) columnar domains. Morphogenetic differences between alar and basal plates in the prosencephalon and mesencephalon contribute to the characteristic expansion of alar plate derivatives in the brain and the formation of the cephalic flexure. Although differential histogenesis among DV regions seems to be relevant in understanding structural and functional complexity of the brain, most of our knowledge about DV regionalization comes from the spinal cord development. Therefore, it seems of interest to study the molecular mechanisms that govern DV patterning in the diencephalon, the brain region where strong differences in size and complexity between alar and basal derivatives are evident in all vertebrates. Different morphogenetic signals, which induce specific progenitors fate to the neighboring epithelium, are involved in the spinal cord DV patterning. To study if Wnt1, one of these signaling molecules, has a role for the establishment of the diencephalic longitudinal domains, we carried out gain- and loss-of-function experiments, using mice and chick embryos. Our results demonstrated functional differences in the molecular mechanisms downstream of Wnt1 function in the diencephalon, in relation to the spinal cord. We further demonstrated that Bmp4 signal induces Wnt1 expression in the diencephalon, unraveling a new molecular regulatory code downstream of primary dorsalizing signals to control ventral regionalization in the diencephalon.
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Hedgehog signaling activates a positive feedback mechanism involving insulin-like growth factors to induce osteoblast differentiation. Proc Natl Acad Sci U S A 2015; 112:4678-83. [PMID: 25825734 DOI: 10.1073/pnas.1502301112] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Hedgehog (Hh) signaling is essential for osteoblast differentiation in the endochondral skeleton during embryogenesis. However, the molecular mechanism underlying the osteoblastogenic role of Hh is not completely understood. Here, we report that Hh markedly induces the expression of insulin-like growth factor 2 (Igf2) that activates the mTORC2-Akt signaling cascade during osteoblast differentiation. Igf2-Akt signaling, in turn, stabilizes full-length Gli2 through Serine 230, thus enhancing the output of transcriptional activation by Hh. Importantly, genetic deletion of the Igf signaling receptor Igf1r specifically in Hh-responding cells diminishes bone formation in the mouse embryo. Thus, Hh engages Igf signaling in a positive feedback mechanism to activate the osteogenic program.
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Guo F, Lang J, Sohn J, Hammond E, Chang M, Pleasure D. Canonical Wnt signaling in the oligodendroglial lineage-puzzles remain. Glia 2015; 63:1671-93. [DOI: 10.1002/glia.22813] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 02/17/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Fuzheng Guo
- Neurology Department; School of Medicine at UC Davis Medical Center; Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, Northern California; Sacramento California
| | - Jordan Lang
- Neurology Department; School of Medicine at UC Davis Medical Center; Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, Northern California; Sacramento California
| | - Jiho Sohn
- Neurology Department; School of Medicine at UC Davis Medical Center; Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, Northern California; Sacramento California
| | - Elizabeth Hammond
- Neurology Department; School of Medicine at UC Davis Medical Center; Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, Northern California; Sacramento California
| | - Marcello Chang
- Neurology Department; School of Medicine at UC Davis Medical Center; Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, Northern California; Sacramento California
| | - David Pleasure
- Neurology Department; School of Medicine at UC Davis Medical Center; Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, Northern California; Sacramento California
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Juraver-Geslin HA, Durand BC. Early development of the neural plate: new roles for apoptosis and for one of its main effectors caspase-3. Genesis 2015; 53:203-24. [PMID: 25619400 DOI: 10.1002/dvg.22844] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/07/2015] [Indexed: 12/12/2022]
Abstract
Despite its tremendous complexity, the vertebrate nervous system emerges from a homogenous layer of neuroepithelial cells, the neural plate. Its formation relies on the time- and space-controlled progression of developmental programs. Apoptosis is a biological process that removes superfluous and potentially dangerous cells and is implemented through the activation of a molecular pathway conserved during evolution. Apoptosis and an unconventional function of one of its main effectors, caspase-3, contribute to the patterning and growth of the neuroepithelium. Little is known about the intrinsic and extrinsic cues controlling activities of the apoptotic machinery during development. The BarH-like (Barhl) proteins are homeodomain-containing transcription factors. The observations in Caenorhabditis elegans, Xenopus, and mice document that Barhl proteins act in cell survival and as cell type-specific regulators of a caspase-3 function that limits neural progenitor proliferation. In this review, we discuss the roles and regulatory modes of the apoptotic machinery in the development of the neural plate. We focus on the Barhl2, the Sonic Hedgehog, and the Wnt pathways and their activities in neural progenitor survival and proliferation.
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Affiliation(s)
- Hugo A Juraver-Geslin
- Department of Basic Science, Craniofacial Biology, College of Dentistry, New York University, New York, New York
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Stifani N. Motor neurons and the generation of spinal motor neuron diversity. Front Cell Neurosci 2014; 8:293. [PMID: 25346659 PMCID: PMC4191298 DOI: 10.3389/fncel.2014.00293] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 09/02/2014] [Indexed: 11/13/2022] Open
Abstract
Motor neurons (MNs) are neuronal cells located in the central nervous system (CNS) controlling a variety of downstream targets. This function infers the existence of MN subtypes matching the identity of the targets they innervate. To illustrate the mechanism involved in the generation of cellular diversity and the acquisition of specific identity, this review will focus on spinal MNs (SpMNs) that have been the core of significant work and discoveries during the last decades. SpMNs are responsible for the contraction of effector muscles in the periphery. Humans possess more than 500 different skeletal muscles capable to work in a precise time and space coordination to generate complex movements such as walking or grasping. To ensure such refined coordination, SpMNs must retain the identity of the muscle they innervate. Within the last two decades, scientists around the world have produced considerable efforts to elucidate several critical steps of SpMNs differentiation. During development, SpMNs emerge from dividing progenitor cells located in the medial portion of the ventral neural tube. MN identities are established by patterning cues working in cooperation with intrinsic sets of transcription factors. As the embryo develop, MNs further differentiate in a stepwise manner to form compact anatomical groups termed pools connecting to a unique muscle target. MN pools are not homogeneous and comprise subtypes according to the muscle fibers they innervate. This article aims to provide a global view of MN classification as well as an up-to-date review of the molecular mechanisms involved in the generation of SpMN diversity. Remaining conundrums will be discussed since a complete understanding of those mechanisms constitutes the foundation required for the elaboration of prospective MN regeneration therapies.
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Affiliation(s)
- Nicolas Stifani
- Medical Neuroscience, Dalhousie University Halifax, NS, Canada
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20
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Vied CM, Freudenberg F, Wang Y, Raposo AASF, Feng D, Nowakowski RS. A multi-resource data integration approach: identification of candidate genes regulating cell proliferation during neocortical development. Front Neurosci 2014; 8:257. [PMID: 25191221 PMCID: PMC4139594 DOI: 10.3389/fnins.2014.00257] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/01/2014] [Indexed: 11/17/2022] Open
Abstract
Neurons of the mammalian neocortex are produced by proliferating cells located in the ventricular zone (VZ) lining the lateral ventricles. This is a complex and sequential process, requiring precise control of cell cycle progression, fate commitment and differentiation. We have analyzed publicly available databases from mouse and human to identify candidate genes that are potentially involved in regulating early neocortical development and neurogenesis. We used a mouse in situ hybridization dataset (The Allen Institute for Brain Science) to identify 13 genes (Cdon, Celsr1, Dbi, E2f5, Eomes, Hmgn2, Neurog2, Notch1, Pcnt, Sox3, Ssrp1, Tead2, Tgif2) with high correlation of expression in the proliferating cells of the VZ of the neocortex at early stages of development (E15.5). We generated a similar human brain network using microarray and RNA-seq data (BrainSpan Atlas) and identified 407 genes with high expression in the developing human VZ and subventricular zone (SVZ) at 8–9 post-conception weeks. Seven of the human genes were also present in the mouse VZ network. The human and mouse networks were extended using available genetic and proteomic datasets through GeneMANIA. A gene ontology search of the mouse and human networks indicated that many of the genes are involved in the cell cycle, DNA replication, mitosis and transcriptional regulation. The reported involvement of Cdon, Celsr1, Dbi, Eomes, Neurog2, Notch1, Pcnt, Sox3, Tead2, and Tgif2 in neural development or diseases resulting from the disruption of neurogenesis validates these candidate genes. Taken together, our knowledge-based discovery method has validated the involvement of many genes already known to be involved in neocortical development and extended the potential number of genes by 100's, many of which are involved in functions related to cell proliferation but others of which are potential candidates for involvement in the regulation of neocortical development.
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Affiliation(s)
- Cynthia M Vied
- Department of Biomedical Sciences, College of Medicine, Florida State University Tallahassee, FL, USA
| | - Florian Freudenberg
- Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital of Frankfurt Frankfurt, Germany
| | - Yuting Wang
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore Singapore, Singapore
| | | | - David Feng
- Allen Institute for Brain Science Seattle, WA, USA
| | - Richard S Nowakowski
- Department of Biomedical Sciences, College of Medicine, Florida State University Tallahassee, FL, USA
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21
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Zhang Z, Lin CCJ. Taking advantage of neural development to treat glioblastoma. Eur J Neurosci 2014; 40:2859-66. [PMID: 24964151 DOI: 10.1111/ejn.12655] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 04/29/2014] [Accepted: 05/11/2014] [Indexed: 01/02/2023]
Abstract
Glioblastoma (GBM) is by far the most common and most malignant primary adult brain tumor (World Health Organization grade IV), containing a fraction of stem-like cells that are highly tumorigenic and multipotent. Recent research has revealed that GBM stem-like cells play important roles in GBM pathogenesis. GBM is thought to arise from genetic anomalies in glial development. Over the past decade, a wide range of studies have shown that several signaling pathways involved in neural development, including basic helix-loop-helix, Wnt-β-catenin, bone morphogenetic proteins-Smads, epidermal growth factor-epidermal growth factor receptor, and Notch, play important roles in GBM pathogenesis. In this review, we highlight the significance of these pathways in the context of developing treatments for GBM. Extrapolating knowledge and concepts from neural development will have significant implications for designing better strategies with which to treat GBM.
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Affiliation(s)
- Zhiyuan Zhang
- Department of Neurosurgery, Nanjing Jinling Hospital, School of Medicine, Nanjing University, Jiangsu Province, China; Center for Cell and Gene Therapy, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
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22
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Korzh V. Stretching cell morphogenesis during late neurulation and mild neural tube defects. Dev Growth Differ 2014; 56:425-33. [DOI: 10.1111/dgd.12143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 01/07/2023]
Affiliation(s)
- Vladimir Korzh
- Institute of Molecular and Cell Biology; Singapore
- Department of Biological Sciences; National University of Singapore; Singapore
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23
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Zhao C. Paracrine signaling in stem cell renewal and in neoplastic tumor growth. SCIENCE CHINA-LIFE SCIENCES 2014; 57:571-4. [DOI: 10.1007/s11427-014-4664-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 04/02/2014] [Indexed: 01/11/2023]
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24
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Francius C, Clotman F. Generating spinal motor neuron diversity: a long quest for neuronal identity. Cell Mol Life Sci 2014; 71:813-29. [PMID: 23765105 PMCID: PMC11113339 DOI: 10.1007/s00018-013-1398-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 05/30/2013] [Accepted: 05/31/2013] [Indexed: 03/26/2023]
Abstract
Understanding how thousands of different neuronal types are generated in the CNS constitutes a major challenge for developmental neurobiologists and is a prerequisite before considering cell or gene therapies of nervous lesions or pathologies. During embryonic development, spinal motor neurons (MNs) segregate into distinct subpopulations that display specific characteristics and properties including molecular identity, migration pattern, allocation to specific motor columns, and innervation of defined target. Because of the facility to correlate these different characteristics, the diversification of spinal MNs has become the model of choice for studying the molecular and cellular mechanisms underlying the generation of multiple neuronal populations in the developing CNS. Therefore, how spinal motor neuron subpopulations are produced during development has been extensively studied during the last two decades. In this review article, we will provide a comprehensive overview of the genetic and molecular mechanisms that contribute to the diversification of spinal MNs.
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Affiliation(s)
- Cédric Francius
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, 55 Avenue Hippocrate, Box (B1.55.11), 1200 Brussels, Belgium
| | - Frédéric Clotman
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, 55 Avenue Hippocrate, Box (B1.55.11), 1200 Brussels, Belgium
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25
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Transgenic overexpression of Sox17 promotes oligodendrocyte development and attenuates demyelination. J Neurosci 2013; 33:12528-42. [PMID: 23884956 DOI: 10.1523/jneurosci.0536-13.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have previously demonstrated that Sox17 regulates cell cycle exit and differentiation in oligodendrocyte progenitor cells. Here we investigated its function in white matter (WM) development and adult injury with a newly generated transgenic mouse overexpressing Sox17 in the oligodendrocyte lineage under the CNPase promoter. Sox17 overexpression in CNP-Sox17 mice sequentially promoted postnatal oligodendrogenesis, increasing NG2 progenitor cells from postnatal day (P) 15, then O4+ and CC1+ cells at P30 and P120, respectively. Total Olig2+ oligodendrocyte lineage cells first decreased between P8 and P22 through Sox17-mediated increase in apoptotic cell death, and thereafter significantly exceeded WT levels from P30 when cell death had ceased. CNP-Sox17 mice showed increased Gli2 protein levels and Gli2+ cells in WM, indicating that Sox17 promotes the generation of oligodendrocyte lineage cells through Hedgehog signaling. Sox17 overexpression prevented cell loss after lysolecithin-induced demyelination by increasing Olig2+ and CC1+ cells in response to injury. Furthermore, Sox17 overexpression abolished the injury-induced increase in TCF7L2/TCF4+ cells, and protected oligodendrocytes from apoptosis by preventing decreases in Gli2 and Bcl-2 expression that were observed in WT lesions. Our study thus reveals a biphasic effect of Sox17 overexpression on cell survival and oligodendrocyte formation in the developing WM, and that its potentiation of oligodendrocyte survival in the adult confers resistance to injury and myelin loss. This study demonstrates that overexpression of this transcription factor might be a viable protective strategy to mitigate the consequences of demyelination in the adult WM.
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26
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Gray JD, Kholmanskikh S, Castaldo BS, Hansler A, Chung H, Klotz B, Singh S, Brown AMC, Ross ME. LRP6 exerts non-canonical effects on Wnt signaling during neural tube closure. Hum Mol Genet 2013; 22:4267-81. [PMID: 23773994 DOI: 10.1093/hmg/ddt277] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Low-density lipoprotein receptor related protein 6 (Lrp6) mutational effects on neurulation were examined using gain (Crooked tail, Lrp6(Cd)) and loss (Lrp6(-)) of function mouse lines. Two features often associated with canonical Wnt signaling, dorsal-ventral patterning and proliferation, were no different from wild-type (WT) in the Lrp6(Cd/Cd) neural tube. Lrp6(-/-) embryos showed reduced proliferation and subtle patterning changes in the neural folds. Cell polarity defects in both Lrp6(Cd/Cd) and Lrp6(-/-) cranial folds were indicated by cell shape, centrosome displacement and failure of F-actin and GTP-RhoA accumulation at the apical surface. Mouse embryonic fibroblasts (MEFs) derived from Lrp6(Cd/Cd) or Lrp6(-/-) embryos exhibited elevated and decreased RhoA basal activity levels, respectively. While ligand-independent activation of canonical Wnt signaling, bypassing Lrp-Frizzled receptors, did not activate RhoA, non-canonical Wnt5a stimulation of RhoA activity was impaired in Lrp6(-/-) MEFs. RhoA inhibition exacerbated NTDs in cultured Lrp6 knockout embryos compared with WT littermates. In contrast, a ROCK inhibitor rescued Lrp6(Cd/Cd) embryos from NTDs. Lrp6 co-immunoprecipitated with Disheveled-associated activator of morphogenesis 1 (DAAM1), a formin promoting GEF activity in Wnt signaling. Biochemical and cell biological data revealed intracellular accumulation of Lrp6(Cd) protein where interaction with DAAM1 could account for observed elevated RhoA activity. Conversely, null mutation that eliminates Lrp6 interaction with DAAM1 led to lower basal RhoA activity in Lrp6(-/-) embryos. These results indicate that Lrp6 mediates not only canonical Wnt signaling, but can also modulate non-canonical pathways involving RhoA-dependent mechanisms to impact neurulation, possibly through intracellular complexes with DAAM1.
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Affiliation(s)
- Jason D Gray
- Brain and Mind Research Institute and Department of Neurology
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27
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Hofmeister W, Key B. Frizzled-3a and Wnt-8b genetically interact during forebrain commissural formation in embryonic zebrafish. Brain Res 2013; 1506:25-34. [PMID: 23438515 DOI: 10.1016/j.brainres.2013.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 02/01/2013] [Accepted: 02/15/2013] [Indexed: 12/31/2022]
Abstract
The commissural plate forms the rostral surface of the embryonic vertebrate forebrain and provides a cellular substrate for forebrain commissural axons. We have previously reported that the Wnt receptor frizzled-3a (fzd3a) restricts the expression of the chemorepulsive guidance ligand slit2 to a discrete domain of neuroepithelial cells in the commissural plate of embryonic zebrafish. Loss of Fzd3a function perturbed slit2 expression and disrupted the formation of glial bridges which guide the formation of forebrain commissures. We now show that Wnt8b is also necessary for anterior commissural formation as well as for patterning of slit2 expression at the midline. Knock down of Wnt8b produced the same phenotype as loss of Fzd3a which suggested that these genes were acting together to regulate axon guidance. Simultaneous sub-threshold knock down of both Fzd3a and Wnt8b led to a greater than additive increase in the penetrance of the mutant phenotype which indicated that these two genes were indeed interacting. We have shown here that Fzd3a/Wnt8b signaling is essential for normal patterning of the commissural plate and that loss-of-function in either receptor or ligand causes Slit2-dependent defects in glial bridge morphology which indirectly attenuated axon midline crossing in the embryonic vertebrate forebrain.
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Affiliation(s)
- Wolfgang Hofmeister
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
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28
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Vaze D, Mahalik S, Rao KLN. Novel association of VACTERL, neural tube defect and crossed renal ectopia: sonic hedgehog signaling: a point of coherence? Congenit Anom (Kyoto) 2012. [PMID: 23181497 DOI: 10.1111/j.1741-4520.2011.00354.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The present case report describes two patients with a novel combination of VACTERL (vertebral, anorectal, cardiac, tracheoesophageal, renal, limb), neural tube defect and crossed renal ectopia. Though cases of VACTERL associated with crossed renal ectopia have been described, the present case report is the first to describe its combination with neural tube defect. The cases reported here are significant because central nervous system manifestations are scarce in VACTERL syndrome. The role of sonic hedgehog pathway has been proposed in VACTERL association and neural tube defects. Axial Sonic hedgehog signaling has also been implicated in the mediolateral positioning of the renal parenchyma. With this knowledge, the etiopathogenesis of this novel combination is discussed to highlight the role of sonic hedgehog signaling as a point of coherence.
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Affiliation(s)
- Dhananjay Vaze
- Department of Pediatric Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
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29
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Su CY, Bay SN, Mariani LE, Hillman MJ, Caspary T. Temporal deletion of Arl13b reveals that a mispatterned neural tube corrects cell fate over time. Development 2012; 139:4062-71. [PMID: 23014696 DOI: 10.1242/dev.082321] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cilia are necessary for sonic hedgehog (Shh) signaling, which is required to pattern the neural tube. We know that ventral neural cell fates are defined by a specific cohort of transcription factors that are induced by distinct thresholds of Shh activity mediated by opposing gradients of Gli activator (GliA) and Gli repressor (GliR). Despite this understanding, the role of Shh as an instructive morphogen is viewed as increasingly complex, with current models integrating positive inputs in terms of ligand concentration and time, along with negative feedback via the downstream gene regulatory network. To investigate the relative contributions of the positive and negative inputs from Shh signaling in neural patterning, we took advantage of a protein that uncouples the regulation of GliA and GliR: the cilia protein ADP-ribosylation factor-like 13b (Arl13b). By deleting Arl13b in mouse, we induced low-level constitutive GliA function at specific developmental stages and defined a crucial period prior to E10.5 when shifts in the level of GliA cause cells to change their fate. Strikingly, we found that improperly patterned cells in these mice converted to the wild-type pattern by E12.5. We further showed that the recovery of patterning did not occur when we also deleted Gli3, the primary GliR in the neural tube, revealing a crucial role of Gli3 in the maintenance of neural patterning.
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Affiliation(s)
- Chen-Ying Su
- Graduate Program in Genetics and Molecular Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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30
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Borday C, Cabochette P, Parain K, Mazurier N, Janssens S, Tran HT, Sekkali B, Bronchain O, Vleminckx K, Locker M, Perron M. Antagonistic cross-regulation between Wnt and Hedgehog signalling pathways controls post-embryonic retinal proliferation. Development 2012; 139:3499-509. [PMID: 22899850 DOI: 10.1242/dev.079582] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Continuous neurogenesis in the adult nervous system requires a delicate balance between proliferation and differentiation. Although Wnt/β-catenin and Hedgehog signalling pathways are thought to share a mitogenic function in adult neural stem/progenitor cells, it remains unclear how they interact in this process. Adult amphibians produce retinal neurons from a pool of neural stem cells localised in the ciliary marginal zone (CMZ). Surprisingly, we found that perturbations of the Wnt and Hedgehog pathways result in opposite proliferative outcomes of neural stem/progenitor cells in the CMZ. Additionally, our study revealed that Wnt and Hedgehog morphogens are produced in mutually exclusive territories of the post-embryonic retina. Using genetic and pharmacological tools, we found that the Wnt and Hedgehog pathways exhibit reciprocal inhibition. Our data suggest that Sfrp-1 and Gli3 contribute to this negative cross-regulation. Altogether, our results reveal an unexpected antagonistic interplay of Wnt and Hedgehog signals that may tightly regulate the extent of neural stem/progenitor cell proliferation in the Xenopus retina.
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31
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Le Dréau G, Martí E. Dorsal-ventral patterning of the neural tube: a tale of three signals. Dev Neurobiol 2012; 72:1471-81. [PMID: 22821665 DOI: 10.1002/dneu.22015] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/16/2012] [Accepted: 02/17/2012] [Indexed: 12/16/2022]
Abstract
Development of the vertebrate nervous system begins with the acquisition of neural identity from the midline dorsal-ectodermal cells of the gastrulating embryos. The subsequent progressive specification of the neural plate along its anterior-posterior and dorsal-ventral (DV) axes allows the generation of the tremendous variety of neuronal and glial cells that compose the vertebrate central nervous system (CNS). Studies on the development of the spinal cord, the anatomically simplest part of the CNS, have generated most of our current knowledge on the signaling events and the genetic networks that orchestrate the DV patterning of the neural plate. In this review, we discuss the recent advances in our understanding of these events and highlight unresolved questions. We focused our attention on the activity and the integration of the three main instructive cues: Sonic hedgehog, the Wnts and the Bone Morphogenetic Proteins, giving particular attention to the less well understood dorsal signaling events.
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Affiliation(s)
- Gwenvael Le Dréau
- Instituto de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Spain
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32
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Bluske KK, Vue TY, Kawakami Y, Taketo MM, Yoshikawa K, Johnson JE, Nakagawa Y. β-Catenin signaling specifies progenitor cell identity in parallel with Shh signaling in the developing mammalian thalamus. Development 2012; 139:2692-702. [PMID: 22745311 DOI: 10.1242/dev.072314] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neural progenitor cells within the developing thalamus are spatially organized into distinct populations. Their correct specification is critical for generating appropriate neuronal subtypes in specific locations during development. Secreted signaling molecules, such as sonic hedgehog (Shh) and Wnts, are required for the initial formation of the thalamic primordium. Once thalamic identity is established and neurogenesis is initiated, Shh regulates the positional identity of thalamic progenitor cells. Although Wnt/β-catenin signaling also has differential activity within the thalamus during this stage of development, its significance has not been directly addressed. In this study, we used conditional gene manipulations in mice and explored the roles of β-catenin signaling in the regional identity of thalamic progenitor cells. We found β-catenin is required during thalamic neurogenesis to maintain thalamic fate while suppressing prethalamic fate, demonstrating that regulation of regional fate continues to require extrinsic signals. These roles of β-catenin appeared to be mediated at least partly by regulating two basic helix-loop-helix (bHLH) transcription factors, Neurog1 and Neurog2. β-Catenin and Shh signaling function in parallel to specify two progenitor domains within the thalamus, where individual transcription factors expressed in each progenitor domain were regulated differently by the two signaling pathways. We conclude that β-catenin has multiple functions during thalamic neurogenesis and that both Shh and β-catenin pathways are important for specifying distinct types of thalamic progenitor cells, ensuring that the appropriate neuronal subtypes are generated in the correct locations.
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Affiliation(s)
- Krista K Bluske
- Department of Neuroscience, Developmental Biology Center and Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA
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Joubert syndrome: brain and spinal cord malformations in genotyped cases and implications for neurodevelopmental functions of primary cilia. Acta Neuropathol 2012; 123:695-709. [PMID: 22331178 DOI: 10.1007/s00401-012-0951-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 01/25/2012] [Accepted: 01/27/2012] [Indexed: 12/12/2022]
Abstract
Joubert syndrome (JS) is an autosomal recessive ciliopathy characterized by hypotonia, ataxia, abnormal eye movements, and intellectual disability. The brain is malformed, with severe vermian hypoplasia, fourth ventriculomegaly, and "molar tooth" appearance of the cerebral and superior cerebellar peduncles visible as consistent features on neuroimaging. Neuropathological studies, though few, suggest that several other brain and spinal cord structures, such as the dorsal cervicomedullary junction, may also be affected in at least some patients. Genetically, JS is heterogeneous, with mutations in 13 genes accounting for approximately 50% of patients. Here, we compare neuropathologic findings in five subjects with JS, including four with defined mutations in OFD1 (2 siblings), RPGRIP1L, or TCTN2. Characteristic findings in all JS genotypes included vermian hypoplasia, fragmented dentate and spinal trigeminal nuclei, hypoplastic pontine and inferior olivary nuclei, and nondecussation of corticospinal tracts. Other common findings, seen in multiple genotypes but not all subjects, were dorsal cervicomedullary heterotopia, nondecussation of superior cerebellar peduncles, enlarged arcuate nuclei, hypoplastic reticular formation, hypoplastic medial lemnisci, and dorsal spinal cord disorganization. Thus, while JS exhibits significant neuropathologic as well as genetic heterogeneity, no genotype-phenotype correlations are apparent as yet. Our findings suggest that primary cilia are important for neural patterning, progenitor proliferation, cell migration, and axon guidance in the developing human brain and spinal cord.
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Abstract
Abstract
Objectives
Epigenetics refers to the heritable, but reversible regulation of various biological functions. Changes in DNA methylation and chromatin structure derived from histone modifications are involved in the brain development, pathogenesis and pharmacotherapy of brain disorders.
Key findings
Evidence suggests that epigenetic modulations play key roles in psychiatric diseases such as schizophrenia and bipolar disorder. The analysis of epigenetic aberrations in the mechanisms of psychoactive drugs helps to determine dysfunctional genes and pathways in the brain, to predict side effects of drugs on human genome and identify new pharmaceutical targets for treatment of psychiatric diseases.
Summary
Although numerous studies have concentrated on epigenetics of psychosis, the epigenetic studies of antipsychotics are limited. Here we present epigenetic mechanisms of various psychoactive drugs and review the current literature on psychiatric epigenomics. Furthermore, we discuss various epigenetic modulations in the pharmacology and toxicology of typical and atypical antipsychotics, methionine, lithium and valproic acid.
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Affiliation(s)
- Nadka Boyadjieva
- Department of Pharmacology and Toxicology, Medical Faculty, Medical University, Sofia, Bulgaria
- Department of Animal Sciences, Cook College, Rutgers University, New Brunswick, NJ, USA
| | - Miroslava Varadinova
- Department of Pharmacology and Toxicology, Medical Faculty, Medical University, Sofia, Bulgaria
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Halasi G, Søviknes AM, Sigurjonsson O, Glover JC. Proliferation and recapitulation of developmental patterning associated with regulative regeneration of the spinal cord neural tube. Dev Biol 2012; 365:118-32. [PMID: 22370002 DOI: 10.1016/j.ydbio.2012.02.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 01/24/2012] [Accepted: 02/10/2012] [Indexed: 01/13/2023]
Abstract
Developmental patterning during regulative regeneration of the chicken embryo spinal neural tube was characterized by assessing proliferation and the expression of transcription factors specific to neural progenitor and postmitotic neuron populations. One to several segments of the thoracolumbar neural tube were selectively excised unilaterally to initiate regeneration. The capacity for regeneration depended on the stage when ablation was performed and the extent of tissue removed. 20% of surviving embryos exhibited complete regulative regeneration, wherein the missing hemi-neural tube was reconstituted to normal size and morphology. Fate-mapping of proliferative adjacent tissue indicated contributions from the opposite side of the neural tube and potentially from the ipsilateral neural tube rostral and caudal to the lesion. Application of the thymidine analog EdU (5-ethynyl-2'-deoxyuridine) demonstrated a moderate increase in cell proliferation in lesioned relative to control embryos, and quantitative PCR demonstrated a parallel moderate increase in transcription of proliferation-related genes. Mathematical calculation showed that such modest increases are sufficient to account for the amount of regenerated tissue. Within the regenerated neural tube the expression pattern of progenitor-specific transcription factors was recapitulated in the separate advancing ventral and dorsal fronts of regeneration, with no evidence of abnormal mixing of progenitor subpopulations, indicating that graded patterning mechanisms do not require continuity of neural tube tissue along the dorsoventral axis and do not involve a sorting out of committed progenitors. Upon completion of the regeneration process, the pattern of neuron-specific transcription factor expression was essentially normal. Modest deficits in the numbers of transcription factor-defined neuron types were evident in the regenerated tissue, increasing particularly in dorsal neuron types with later lesions. These results confirm the regulative potential of the spinal neural tube and demonstrate a capacity for re-establishing appropriate cellular patterning despite a grossly abnormal morphogenetic situation.
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Affiliation(s)
- Gabor Halasi
- Laboratory of Neural Development and Optical Recording (NDEVOR), Department of Physiology, Institute of Basic Medical Sciences, Domus Medica, University of Oslo, PB 1103 Blindern, 0317 Oslo, Norway
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Joksimovic M, Patel M, Taketo MM, Johnson R, Awatramani R. Ectopic Wnt/beta-catenin signaling induces neurogenesis in the spinal cord and hindbrain floor plate. PLoS One 2012; 7:e30266. [PMID: 22276170 PMCID: PMC3261891 DOI: 10.1371/journal.pone.0030266] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 12/12/2011] [Indexed: 01/08/2023] Open
Abstract
The most ventral structure of the developing neural tube, the floor plate (FP), differs in neurogenic capacity along the neuraxis. The FP is largely non-neurogenic at the hindbrain and spinal cord levels, but generates large numbers of dopamine (mDA) neurons at the midbrain levels. Wnt1, and other Wnts are expressed in the ventral midbrain, and Wnt/beta catenin signaling can at least in part account for the difference in neurogenic capacity of the FP between midbrain and hindbrain levels. To further develop the hypothesis that canonical Wnt signaling promotes mDA specification and FP neurogenesis, we have generated a model wherein beta–catenin is conditionally stabilized throughout the FP. Here, we unambiguously show by fate mapping FP cells in this mutant, that the hindbrain and spinal cord FP are rendered highly neurogenic, producing large numbers of neurons. We reveal that a neurogenic hindbrain FP results in the altered settling pattern of neighboring precerebellar neuronal clusters. Moreover, in this mutant, mDA progenitor markers are induced throughout the rostrocaudal axis of the hindbrain FP, although TH+ mDA neurons are produced only in the rostral aspect of rhombomere (r)1. This is, at least in part, due to depressed Lmx1b levels by Wnt/beta catenin signaling; indeed, when Lmx1b levels are restored in this mutant, mDA are observed not only in rostral r1, but also at more caudal axial levels in the hindbrain, but not in the spinal cord. Taken together, these data elucidate both patterning and neurogenic functions of Wnt/beta catenin signaling in the FP, and thereby add to our understanding of the molecular logic of mDA specification and neurogenesis.
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Affiliation(s)
- Milan Joksimovic
- Department of Neurology and Center for Genetic Medicine, Feinberg Medical School, Northwestern University, Chicago, Illinois, United States of America
| | - Meera Patel
- Department of Neurology and Center for Genetic Medicine, Feinberg Medical School, Northwestern University, Chicago, Illinois, United States of America
| | - Makoto Mark Taketo
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Yoshida-Konoé-cho, Sakyo, Kyoto, Japan
| | - Randy Johnson
- Department of Biochemistry and Molecular Biology, University of Texas, M. D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Rajeshwar Awatramani
- Department of Neurology and Center for Genetic Medicine, Feinberg Medical School, Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
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Wilson NH, Stoeckli ET. Sonic Hedgehog regulates Wnt activity during neural circuit formation. VITAMINS AND HORMONES 2012; 88:173-209. [PMID: 22391304 DOI: 10.1016/b978-0-12-394622-5.00008-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Gradients of secreted morphogens, such as Sonic hedgehog (Shh), Wnt, and TGFβ/Bmp, have classically been shown to control many aspects of early development by regulating cell proliferation and determining cell fate. However, recent studies demonstrate that these molecules also play important and evolutionarily conserved roles in later aspects of neural development. Depending on the context, these molecules can elicit gene transcription in the nucleus, or alternatively can provide instructive signals at the growth cone that induce local and rapid changes in cytoskeletal organization. Shh can activate different cellular transduction pathways via its binding to alternative coreceptor complexes or simply by adaptation of its "classical" signaling pathway. However, in most of its activities during neural development, Shh does not act alone but rather in concert with other morphogens, particularly the Wnts. This review provides an overview of the mechanisms by which Shh signaling acts in concert with Wnts to mediate a myriad of cellular processes that are required for neural circuit formation.
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Affiliation(s)
- Nicole H Wilson
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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Kim HS, Dorsky RI. Tcf7l1 is required for spinal cord progenitor maintenance. Dev Dyn 2011; 240:2256-64. [PMID: 21932308 DOI: 10.1002/dvdy.22716] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2011] [Indexed: 01/02/2023] Open
Abstract
Neural progenitor cells must be maintained during development in order to produce the full complement of neuronal and glial derivatives. While molecular pathways have been identified that inhibit progenitor differentiation, it is unclear whether the progenitor state itself is actively maintained. In this study, we have investigated the role of Tcf7l1 (formerly named Tcf3) in maintaining spinal progenitor characteristics and allowing the continued production of neurons and glia following primary neurogenesis. We find that spinal cord progenitor markers are progressively lost in embryos lacking Tcf7l1, and that the number of proliferative progenitors decreases accordingly. Furthermore, we show that the production of both neuronal and glial secondary derivatives of the pMN progenitor pool requires Tcf7l1. Together, these results indicate that Tcf7l1 plays an important role in spinal cord progenitor maintenance, indicating that this core function is conserved throughout multiple epithelial cell populations.
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Affiliation(s)
- Hyung-Seok Kim
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA
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Wang H, Lei Q, Oosterveen T, Ericson J, Matise MP. Tcf/Lef repressors differentially regulate Shh-Gli target gene activation thresholds to generate progenitor patterning in the developing CNS. Development 2011; 138:3711-21. [PMID: 21775418 DOI: 10.1242/dev.068270] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During neural tube development, Shh signaling through Gli transcription factors is necessary to establish five distinct ventral progenitor domains that give rise to unique classes of neurons and glia that arise in specific positions along the dorsoventral axis. These cells are generated from progenitors that display distinct transcription factor gene expression profiles in specific domains in the ventricular zone. However, the molecular genetic mechanisms that control the differential spatiotemporal transcriptional responses of progenitor target genes to graded Shh-Gli signaling remain unclear. The current study demonstrates a role for Tcf/Lef repressor activity in this process. We show that Tcf3 and Tcf7L2 (Tcf4) are required for proper ventral patterning and function by independently regulating two Shh-Gli target genes, Nkx2.2 and Olig2, which are initially induced in a common pool of progenitors that ultimately segregate into unique territories giving rise to distinct progeny. Genetic and functional studies in vivo show that Tcf transcriptional repressors selectively elevate the strength and duration of Gli activity necessary to induce Nkx2.2, but have no effect on Olig2, and thereby contribute to the establishment of their distinct expression domains in cooperation with graded Shh signaling. Together, our data reveal a Shh-Gli-independent transcriptional input that is required to shape the precise spatial and temporal response to extracellular morphogen signaling information during lineage segregation in the CNS.
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Affiliation(s)
- Hui Wang
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA
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David MD, Cantí C, Herreros J. Wnt-3a and Wnt-3 differently stimulate proliferation and neurogenesis of spinal neural precursors and promote neurite outgrowth by canonical signaling. J Neurosci Res 2011; 88:3011-23. [PMID: 20722074 DOI: 10.1002/jnr.22464] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Wnt factors regulate neural stem cell development and neuronal connectivity. Here we investigated whether Wnt-3a and Wnt-3, expressed in the developing spinal cord, regulate proliferation and the neuronal differentiation of spinal cord neural precursors (SCNP). Wnt-3a promoted a sustained increase of SCNP proliferation and decreased the expression of cyclin-dependent kinase inhibitors. In contrast, Wnt-3 transiently enhanced SCNP proliferation and increased neurogenesis through β-catenin signaling. Furthermore, both Wnt-3a and Wnt-3 stimulated neurite outgrowth in SCNP-derived neurons through β-catenin- and TCF4-dependent transcription. Glycogen synthase kinase-3β inhibitors mimicked Wnt signaling and promoted neurite outgrowth in established cultures. We conclude that Wnt-3a and Wnt-3 factors signal through the canonical Wnt/β-catenin pathway to regulate different aspects of SCNP development. These findings may be of therapeutic interest for the treatment of neurodegenerative diseases and nerve injury.
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Affiliation(s)
- Monica D David
- Laboratori d'Investigació, Hospital Universitari Arnau de Vilanova, Departament de Ciències Mèdiques Bàsiques, IRBLleida-University of Lleida, Lleida, Spain
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41
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Horner VL, Caspary T. Disrupted dorsal neural tube BMP signaling in the cilia mutant Arl13b hnn stems from abnormal Shh signaling. Dev Biol 2011; 355:43-54. [PMID: 21539826 DOI: 10.1016/j.ydbio.2011.04.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 03/22/2011] [Accepted: 04/14/2011] [Indexed: 12/22/2022]
Abstract
In the embryonic neural tube, multiple signaling pathways work in concert to create functional neuronal circuits in the adult spinal cord. In the ventral neural tube, Sonic hedgehog (Shh) acts as a graded morphogen to specify neurons necessary for movement. In the dorsal neural tube, bone morphogenetic protein (BMP) and Wnt signals cooperate to specify neurons involved in sensation. Several signaling pathways, including Shh, rely on primary cilia in vertebrates. In this study, we used a mouse mutant with abnormal cilia, Arl13b(hnn), to study the relationship between cilia, cell signaling, and neural tube patterning. Arl13b(hnn) mutants have abnormal ventral neural tube patterning due to disrupted Shh signaling; in addition, dorsal patterning defects occur, but the cause of these is unknown. Here we show that the Arl13b(hnn) dorsal patterning defects result from abnormal BMP signaling. In addition, we find that Wnt ligands are abnormally expressed in Arl13b(hnn) mutants; surprisingly, however, downstream Wnt signaling is normal. We demonstrate that Arl13b is required non-autonomously for BMP signaling and Wnt ligand expression, indicating that the abnormal Shh signaling environment in Arl13b(hnn) embryos indirectly causes dorsal defects.
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Affiliation(s)
- Vanessa L Horner
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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42
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Murdoch JN, Copp AJ. The relationship between sonic Hedgehog signaling, cilia, and neural tube defects. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2010; 88:633-52. [PMID: 20544799 PMCID: PMC3635124 DOI: 10.1002/bdra.20686] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Hedgehog signaling pathway is essential for many aspects of normal embryonic development, including formation and patterning of the neural tube. Absence of the sonic hedgehog (shh) ligand is associated with the midline defect holoprosencephaly, whereas increased Shh signaling is associated with exencephaly and spina bifida. To complicate this apparently simple relationship, mutation of proteins required for function of cilia often leads to impaired Shh signaling and to disruption of neural tube closure. In this article, we review the literature on Shh pathway mutants and discuss the relationship between Shh signaling, cilia, and neural tube defects.
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Affiliation(s)
- Jennifer N Murdoch
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK.
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Cai C, Tamai K, Molyneaux K. KHDC1B is a novel CPEB binding partner specifically expressed in mouse oocytes and early embryos. Mol Biol Cell 2010; 21:3137-48. [PMID: 20668163 PMCID: PMC2938380 DOI: 10.1091/mbc.e10-03-0255] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
mRNAs required for meiotic maturation and early embryonic development are stored in growing oocytes. These transcripts are translationally repressed until hormonal cues trigger ovulation. Errors in translation underlie some cases of human infertility and are associated with ovarian germ cell tumors. However, it remains unclear how maternal transcripts are kept quiescent in mammals. This study describes a potential translational regulator, KHDC1B. KHDC1B is a member of a small family of KH-domain containing proteins specific to eutherian mammals. Two family members, KHDC1A and 1B, are highly expressed in oocytes. KHDC1A and 1B bind polyU agarose and form oligomers like other KH-domain proteins. The functions of these proteins were tested by expression in Xenopus embryos. KHDC1A caused cell death, whereas KHDC1B caused cleavage arrest. This arrest phenotype was rescued by coexpression of the mouse translational regulator cytoplasmic polyadenylation binding protein 1 (mCPEB1). Coimmunoprecipitation and coimmunostaining experiments confirmed the functional interaction between KHDC1B and mCPEB1. Finally, KHDC1B levels and binding partners were shown to fluctuate with the cell cycle. KHDC1B, via its interaction with mCEPB1, may regulate translation of mRNA targets required for oocyte maturation.
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Affiliation(s)
- Congli Cai
- Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
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44
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APCDD1 is a novel Wnt inhibitor mutated in hereditary hypotrichosis simplex. Nature 2010; 464:1043-7. [PMID: 20393562 DOI: 10.1038/nature08875] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Accepted: 02/03/2010] [Indexed: 11/08/2022]
Abstract
Hereditary hypotrichosis simplex is a rare autosomal dominant form of hair loss characterized by hair follicle miniaturization. Using genetic linkage analysis, we mapped a new locus for the disease to chromosome 18p11.22, and identified a mutation (Leu9Arg) in the adenomatosis polyposis down-regulated 1 (APCDD1) gene in three families. We show that APCDD1 is a membrane-bound glycoprotein that is abundantly expressed in human hair follicles, and can interact in vitro with WNT3A and LRP5-two essential components of Wnt signalling. Functional studies show that APCDD1 inhibits Wnt signalling in a cell-autonomous manner and functions upstream of beta-catenin. Moreover, APCDD1 represses activation of Wnt reporters and target genes, and inhibits the biological effects of Wnt signalling during both the generation of neurons from progenitors in the developing chick nervous system, and axis specification in Xenopus laevis embryos. The mutation Leu9Arg is located in the signal peptide of APCDD1, and perturbs its translational processing from the endoplasmic reticulum to the plasma membrane. APCDD1(L9R) probably functions in a dominant-negative manner to inhibit the stability and membrane localization of the wild-type protein. These findings describe a novel inhibitor of the Wnt signalling pathway with an essential role in human hair growth. As APCDD1 is expressed in a broad repertoire of cell types, our findings indicate that APCDD1 may regulate a diversity of biological processes controlled by Wnt signalling.
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Human intronic enhancers control distinct sub-domains of Gli3 expression during mouse CNS and limb development. BMC DEVELOPMENTAL BIOLOGY 2010; 10:44. [PMID: 20426846 PMCID: PMC2875213 DOI: 10.1186/1471-213x-10-44] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 04/28/2010] [Indexed: 11/18/2022]
Abstract
Background The zinc-finger transcription factor GLI3 is an important mediator of Sonic hedgehog signaling and crucial for patterning of many aspects of the vertebrate body plan. In vertebrates, the mechanism of SHH signal transduction and its action on target genes by means of activating or repressing forms of GLI3 have been studied most extensively during limb development and the specification of the central nervous system. From these studies it has emerged, that Gli3 expression must be subject to a tight spatiotemporal regulation. However, the genetic mechanisms and the cis-acting elements controlling the expression of Gli3 remained largely unknown. Results Here, we demonstrate in chicken and mouse transgenic embryos that human GLI3-intronic conserved non-coding sequence elements (CNEs) autonomously control individual aspects of Gli3 expression. Their combined action shows many aspects of a Gli3-specific pattern of transcriptional activity. In the mouse limb bud, different CNEs enhance Gli3-specific expression in evolutionary ancient stylopod and zeugopod versus modern skeletal structures of the autopod. Limb bud specificity is also found in chicken but had not been detected in zebrafish embryos. Three of these elements govern central nervous system specific gene expression during mouse embryogenesis, each targeting a subset of endogenous Gli3 transcription sites. Even though fish, birds, and mammals share an ancient repertoire of gene regulatory elements within Gli3, the functions of individual enhancers from this catalog have diverged significantly. During evolution, ancient broad-range regulatory elements within Gli3 attained higher specificity, critical for patterning of more specialized structures, by abolishing the potential for redundant expression control. Conclusion These results not only demonstrate the high level of complexity in the genetic mechanisms controlling Gli3 expression, but also reveal the evolutionary significance of cis-acting regulatory networks of early developmental regulators in vertebrates.
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Ulloa F, Martí E. Wnt won the war: antagonistic role of Wnt over Shh controls dorso-ventral patterning of the vertebrate neural tube. Dev Dyn 2010; 239:69-76. [PMID: 19681160 DOI: 10.1002/dvdy.22058] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The spinal cord has been used as a model to dissect the mechanisms that govern the patterning of tissues during animal development, since the principles that rule the dorso-ventral patterning of the neural tube are applicable to other systems. Signals that determine the dorso-ventral axis of the spinal cord include Sonic hedgehog (Shh), acting as a bona fide morphogenetic signal to determine ventral progenitor identities, and members of the Bmp and the Wnt families, acting in the dorsal neural tube. Although Wnts have been initially recognized as important in proliferation of neural progenitor cells, their role in the dorso-ventral patterning has been controversial. In this review, we discuss recent reports that show an important contribution of the Wnt canonical pathway in dorso-ventral pattern formation. These data allow building a model by which the ventralizing activity of Shh is antagonized by Wnt activity through the expression of Gli3, a potent inhibitor of the Shh pathway. Therefore, antagonistic interactions between canonical Wnt, promoting dorsal identities, and Shh pathways, inducing ventral ones, would define the dorso-ventral patterning of the developing central nervous system.
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Affiliation(s)
- Fausto Ulloa
- Institute for Research in Biomedicine, Parc Cientific de Barcelona; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Department of Cell Biology, University of Barcelona, Barcelona, Spain
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47
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Li XJ, Zhang X, Johnson MA, Wang ZB, Lavaute T, Zhang SC. Coordination of sonic hedgehog and Wnt signaling determines ventral and dorsal telencephalic neuron types from human embryonic stem cells. Development 2009; 136:4055-63. [PMID: 19906872 DOI: 10.1242/dev.036624] [Citation(s) in RCA: 241] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The directed differentiation of forebrain neuronal types from human embryonic stem cells (hESCs) has not been achieved. Here, we show that hESCs differentiate to telencephalic progenitors with a predominantly dorsal identity in a chemically defined medium without known morphogens. This is attributed to endogenous Wnt signaling, which upregulates the truncated form of GLI3, a repressor of sonic hedgehog (SHH). A high concentration of SHH, or the inhibition of Wnt by dickkopf 1 (DKK1) together with a low concentration of SHH, almost completely converts the primitive dorsal precursors to ventral progenitors, which is partially achieved through both downregulation of the truncated GLI3 and upregulation of full-length GLI3 expression. These dorsal and ventral telencephalic progenitors differentiate to functional glutamatergic and GABAergic neurons, respectively. Thus, although hESCs generate dorsal telencephalic cells, as opposed to ventral progenitors in other vertebrates, in the absence of exogenous morphogens, human cells use a similar molecular mechanism to control the dorsal versus ventral fate. The coordination of Wnt and SHH signaling through GLI3 represents a novel mechanism that regulates ventral-dorsal patterning in the development of forebrain neuronal subtypes.
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Affiliation(s)
- Xue-Jun Li
- Department of Neuroscience, Stem Cell Institute, University of Connecticut Health Center, Farmington, CT 06030, USA.
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48
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Quinlan R, Graf M, Mason I, Lumsden A, Kiecker C. Complex and dynamic patterns of Wnt pathway gene expression in the developing chick forebrain. Neural Dev 2009; 4:35. [PMID: 19732418 PMCID: PMC2757023 DOI: 10.1186/1749-8104-4-35] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 09/04/2009] [Indexed: 01/07/2023] Open
Abstract
Background Wnt signalling regulates multiple aspects of brain development in vertebrate embryos. A large number of Wnts are expressed in the embryonic forebrain; however, it is poorly understood which specific Wnt performs which function and how they interact. Wnts are able to activate different intracellular pathways, but which of these pathways become activated in different brain subdivisions also remains enigmatic. Results We have compiled the first comprehensive spatiotemporal atlas of Wnt pathway gene expression at critical stages of forebrain regionalisation in the chick embryo and found that most of these genes are expressed in strikingly dynamic and complex patterns. Several expression domains do not respect proposed compartment boundaries in the developing forebrain, suggesting that areal identities are more dynamic than previously thought. Using an in ovo electroporation approach, we show that Wnt4 expression in the thalamus is negatively regulated by Sonic hedgehog (Shh) signalling from the zona limitans intrathalamica (ZLI), a known organising centre of forebrain development. Conclusion The forebrain is exposed to a multitude of Wnts and Wnt inhibitors that are expressed in a highly dynamic and complex fashion, precluding simple correlative conclusions about their respective functions or signalling mechanisms. In various biological systems, Wnts are antagonised by Shh signalling. By demonstrating that Wnt4 expression in the thalamus is repressed by Shh from the ZLI we reveal an additional level of interaction between these two pathways and provide an example for the cross-regulation between patterning centres during forebrain regionalisation.
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Affiliation(s)
- Robyn Quinlan
- MRC Centre for Developmental Neurobiology, New Hunt's House, Guy's Hospital Campus, King's College, London SE1 1UL, UK.
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Han M, Serrano MC, Lastra-Vicente R, Brinez P, Acharya G, Huhta JC, Chen R, Linask KK. Folate rescues lithium-, homocysteine- and Wnt3A-induced vertebrate cardiac anomalies. Dis Model Mech 2009; 2:467-78. [PMID: 19638421 PMCID: PMC2737056 DOI: 10.1242/dmm.001438] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Accepted: 04/03/2009] [Indexed: 12/20/2022] Open
Abstract
Elevated plasma homocysteine (HCy), which results from folate (folic acid, FA) deficiency, and the mood-stabilizing drug lithium (Li) are both linked to the induction of human congenital heart and neural tube defects. We demonstrated previously that acute administration of Li to pregnant mice on embryonic day (E)6.75 induced cardiac valve defects by potentiating Wnt-beta-catenin signaling. We hypothesized that HCy may similarly induce cardiac defects during gastrulation by targeting the Wnt-beta-catenin pathway. Because dietary FA supplementation protects from neural tube defects, we sought to determine whether FA also protects the embryonic heart from Li- or HCy-induced birth defects and whether the protection occurs by impacting Wnt signaling. Maternal elevation of HCy or Li on E6.75 induced defective heart and placental function on E15.5, as identified non-invasively using echocardiography. This functional analysis of HCy-exposed mouse hearts revealed defects in tricuspid and semilunar valves, together with altered myocardial thickness. A smaller embryo and placental size was observed in the treated groups. FA supplementation ameliorates the observed developmental errors in the Li- or HCy-exposed mouse embryos and normalized heart function. Molecular analysis of gene expression within the avian cardiogenic crescent determined that Li, HCy or Wnt3A suppress Wnt-modulated Hex (also known as Hhex) and Islet-1 (also known as Isl1) expression, and that FA protects from the gene misexpression that is induced by all three factors. Furthermore, myoinositol with FA synergistically enhances the protective effect. Although the specific molecular epigenetic control mechanisms remain to be defined, it appears that Li or HCy induction and FA protection of cardiac defects involve intimate control of the canonical Wnt pathway at a crucial time preceding, and during, early heart organogenesis.
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MESH Headings
- Animals
- Avian Proteins/genetics
- Avian Proteins/metabolism
- Chickens
- Dietary Supplements
- Disease Models, Animal
- Embryo, Mammalian/abnormalities
- Embryo, Mammalian/diagnostic imaging
- Embryo, Mammalian/drug effects
- Embryo, Nonmammalian/abnormalities
- Embryo, Nonmammalian/drug effects
- Folic Acid/pharmacology
- Gastrulation/drug effects
- Gene Expression Regulation, Developmental/drug effects
- Heart Defects, Congenital/chemically induced
- Heart Defects, Congenital/diagnostic imaging
- Heart Defects, Congenital/physiopathology
- Heart Defects, Congenital/prevention & control
- Heart Function Tests/drug effects
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Homocysteine
- Inositol/pharmacology
- LIM-Homeodomain Proteins
- Lithium
- Mice
- Myocardium/metabolism
- Myocardium/pathology
- Transcription Factors
- Ultrasonography
- Wnt Proteins/metabolism
- Wnt3 Protein
- Wnt3A Protein
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Affiliation(s)
- Mingda Han
- Division of Pediatric Cardiology, Department of Pediatrics, USF/ACH Children’s Research Institute, St Petersburg, FL 33701, USA
| | - Maria C. Serrano
- Division of Pediatric Cardiology, Department of Pediatrics, USF/ACH Children’s Research Institute, St Petersburg, FL 33701, USA
| | - Rosana Lastra-Vicente
- Division of Pediatric Cardiology, Department of Pediatrics, USF/ACH Children’s Research Institute, St Petersburg, FL 33701, USA
| | - Pilar Brinez
- Division of Pediatric Cardiology, Department of Pediatrics, USF/ACH Children’s Research Institute, St Petersburg, FL 33701, USA
| | - Ganesh Acharya
- University Hospital of Northern Norway and University of Tromso, Department of Obstetrics and Gynecology, N9308 Tromso, Norway
| | - James C. Huhta
- Division of Pediatric Cardiology, Department of Pediatrics, USF/ACH Children’s Research Institute, St Petersburg, FL 33701, USA
| | - Ren Chen
- USF College of Medicine, Biostatistics Core, Tampa, FL 33612, USA
| | - Kersti K. Linask
- Division of Pediatric Cardiology, Department of Pediatrics, USF/ACH Children’s Research Institute, St Petersburg, FL 33701, USA
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Yu W, Wang Y, McDonnell K, Stephen D, Bai CB. Patterning of ventral telencephalon requires positive function of Gli transcription factors. Dev Biol 2009; 334:264-75. [PMID: 19632216 DOI: 10.1016/j.ydbio.2009.07.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 07/16/2009] [Accepted: 07/17/2009] [Indexed: 10/20/2022]
Abstract
The ability of neuroepithelial cells to generate a diverse array of neurons is influenced by locally secreted signals. In the spinal cord, Sonic Hedgehog (Shh) is known to induce distinct cell fates in a concentration-dependent manner by regulating the activities of the three Gli transcription factors in neural precursors. However, whether Gli-mediated Shh signaling is also required to induce different cell types in the ventral telencephalon has been controversial. In particular, loss of Shh has little effect on dorsoventral patterning of the telencephalon when Gli3 is also removed. Furthermore, no ventral telencephalic phenotypes have been found in individual Gli mutants. To address this issue, we first characterized Shh-responding ventral telencephalic progenitors between E9.5 and E12.5 and found that they produce neurons migrating to different layers of the cortex. We also discovered a loss of Nkx2.1 and Nkx6.2 expression in two subgroups of progenitors in embryos lacking major Gli activators. Finally, we analyzed the telencephalic phenotypes of embryos lacking all Gli genes and found that the ventral telencephalon was highly disorganized with intermingling of distinct neuronal cell types. Together, these studies unravel a role for Gli transcription factors in mediating Shh signaling to control specification, differentiation and positioning of ventral telencephalic neurons.
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Affiliation(s)
- Weiying Yu
- Department of Genetics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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