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Hulett RE, Rivera-López C, Gehrke AR, Gompers A, Srivastava M. A wound-induced differentiation trajectory for neurons. Proc Natl Acad Sci U S A 2024; 121:e2322864121. [PMID: 38976727 PMCID: PMC11260127 DOI: 10.1073/pnas.2322864121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/03/2024] [Indexed: 07/10/2024] Open
Abstract
Animals capable of whole-body regeneration can replace any missing cell type and regenerate fully functional new organs, including new brains, de novo. The regeneration of a new brain requires the formation of diverse neural cell types and their assembly into an organized structure with correctly wired circuits. Recent work in various regenerative animals has revealed transcriptional programs required for the differentiation of distinct neural subpopulations, however, how these transcriptional programs are initiated in response to injury remains unknown. Here, we focused on the highly regenerative acoel worm, Hofstenia miamia, to study wound-induced transcriptional regulatory events that lead to the production of neurons and subsequently a functional brain. Footprinting analysis using chromatin accessibility data on a chromosome-scale genome assembly revealed that binding sites for the Nuclear Factor Y (NFY) transcription factor complex were significantly bound during regeneration, showing a dynamic increase in binding within one hour upon amputation specifically in tail fragments, which will regenerate a new brain. Strikingly, NFY targets were highly enriched for genes with neuronal function. Single-cell transcriptome analysis combined with functional studies identified soxC+ stem cells as a putative progenitor population for multiple neural subtypes. Further, we found that wound-induced soxC expression is likely under direct transcriptional control by NFY, uncovering a mechanism for the initiation of a neural differentiation pathway by early wound-induced binding of a transcriptional regulator.
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Affiliation(s)
- Ryan E. Hulett
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA02138
| | - Carlos Rivera-López
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA02138
- Department of Molecular and Cell Biology, Harvard University, Cambridge, MA02138
| | - Andrew R. Gehrke
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA02138
| | - Annika Gompers
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA02138
| | - Mansi Srivastava
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA02138
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Atac D, Maggi K, Feil S, Maggi J, Cuevas E, Sowden JC, Koller S, Berger W. Identification and Characterization of ATOH7-Regulated Target Genes and Pathways in Human Neuroretinal Development. Cells 2024; 13:1142. [PMID: 38994994 PMCID: PMC11240604 DOI: 10.3390/cells13131142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 06/27/2024] [Accepted: 06/29/2024] [Indexed: 07/13/2024] Open
Abstract
The proneural transcription factor atonal basic helix-loop-helix transcription factor 7 (ATOH7) is expressed in early progenitors in the developing neuroretina. In vertebrates, this is crucial for the development of retinal ganglion cells (RGCs), as mutant animals show an almost complete absence of RGCs, underdeveloped optic nerves, and aberrations in retinal vessel development. Human mutations are rare and result in autosomal recessive optic nerve hypoplasia (ONH) or severe vascular changes, diagnosed as autosomal recessive persistent hyperplasia of the primary vitreous (PHPVAR). To better understand the role of ATOH7 in neuroretinal development, we created ATOH7 knockout and eGFP-expressing ATOH7 reporter human induced pluripotent stem cells (hiPSCs), which were differentiated into early-stage retinal organoids. Target loci regulated by ATOH7 were identified by Cleavage Under Targets and Release Using Nuclease with sequencing (CUT&RUN-seq) and differential expression by RNA sequencing (RNA-seq) of wildtype and mutant organoid-derived reporter cells. Additionally, single-cell RNA sequencing (scRNA-seq) was performed on whole organoids to identify cell type-specific genes. Mutant organoids displayed substantial deficiency in axon sprouting, reduction in RGCs, and an increase in other cell types. We identified 469 differentially expressed target genes, with an overrepresentation of genes belonging to axon development/guidance and Notch signaling. Taken together, we consolidate the function of human ATOH7 in guiding progenitor competence by inducing RGC-specific genes while inhibiting other cell fates. Furthermore, we highlight candidate genes responsible for ATOH7-associated optic nerve and retinovascular anomalies, which sheds light to potential future therapy targets for related disorders.
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Affiliation(s)
- David Atac
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Kevin Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Jordi Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Elisa Cuevas
- UCL Great Ormond Street Institute of Child Health, University College London and NIHR Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
| | - Jane C Sowden
- UCL Great Ormond Street Institute of Child Health, University College London and NIHR Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
| | - Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, 8057 Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
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Hulett RE, Gehrke AR, Gompers A, Rivera-López C, Srivastava M. A wound-induced differentiation trajectory for neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.540286. [PMID: 37214981 PMCID: PMC10197691 DOI: 10.1101/2023.05.10.540286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Animals capable of whole-body regeneration can replace any missing cell type and regenerate fully-functional new organs, de novo . The regeneration of a new brain requires the formation of diverse neuronal cell types and their assembly into an organized structure and correctly-wired circuits. Recent work in various regenerative animals has revealed transcriptional programs required for the differentiation of distinct neuronal subpopulations, however how these transcriptional programs are initiated upon amputation remains unknown. Here, we focused on the highly regenerative acoel worm, Hofstenia miamia , to study wound-induced transcriptional regulatory events that lead to the production of neurons. Footprinting analysis using chromatin accessibility data on an improved genome assembly revealed that binding sites for the NFY transcription factor complex were significantly bound during regeneration, showing a dynamic increase in binding within one hour upon amputation specifically in tail fragments, which will regenerate a new brain. Strikingly, NFY targets were highly enriched for genes with neuronal functional. Single-cell transcriptome analysis combined with functional studies identified sox4 + stem cells as the likely progenitor population for multiple neuronal subtypes. Further, we found that wound-induced sox4 expression is likely under direct transcriptional control by NFY, uncovering a mechanism for how early wound-induced binding of a transcriptional regulator results in the initiation of a neuronal differentiation pathway. Highlights A new chromosome-scale assembly for Hofstenia enables comprehensive analysis of transcription factor binding during regeneration NFY motifs become dynamically bound by 1hpa in regenerating tail fragments, particularly in the loci of neural genes A sox4 + neural-specialized stem cell is identified using scRNA-seq sox4 is wound-induced and required for differentiation of multiple neural cell types NFY regulates wound-induced expression of sox4 during regeneration.
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Yue X, Liang Y, Wei Z, Lv J, Cai Y, Fan X, Zhang W, Chen J. Genome-wide in vitro and in vivo RNAi screens reveal Fer3 to be an important regulator of kkv transcription in Drosophila. INSECT SCIENCE 2022; 29:614-630. [PMID: 34351065 DOI: 10.1111/1744-7917.12954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/24/2021] [Accepted: 07/11/2021] [Indexed: 06/13/2023]
Abstract
Krotzkopf verkehrt (kkv) is a key enzyme that catalyzes the synthesis of chitin, an important component of the Drosophila epidermis, trachea, and other tissues. Here, we report the use of comprehensive RNA interference (RNAi) analyses to search for kkv transcriptional regulators. A cell-based RNAi screen identified 537 candidate kkv regulators on a genome-wide scale. Subsequent use of transgenic Drosophila lines expressing RNAi constructs enabled in vivo validation, and we identified six genes as potential kkv transcriptional regulators. Weakening of the kkvDsRed signal, an in vivo reporter indicating kkv promoter activity, was observed when the expression of Akirin, NFAT, 48 related 3 (Fer3), or Autophagy-related 101(Atg101) was knocked down in Drosophila at the 3rd-instar larval stage; whereas we observed disoriented taenidial folds on larval tracheae when Lines (lin) or Autophagy-related 3 (Atg3) was knocked down in the tracheae. Fer3, in particular, has been shown to be an important factor in the activation of kkv transcription via specific binding with the kkv promoter. The genes involved in the chitin synthesis pathway were widely affected by the downregulation of Fer3. Furthermore, Atg101, Atg3, Akirin, Lin, NFAT, Pnr, and Abd-A showed that the potential complex mechanism of kkv transcription is regulated by an interaction network with bithorax complex components. Our study revealed the hitherto unappreciated diversity of modulators impinging on kkv transcription and opens new avenues in the study of kkv regulation and chitin biosynthesis.
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Affiliation(s)
- Xiangzhao Yue
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- College of Life Sciences, Shangrao Normal University, Shangrao, Jiangxi Province, China
| | - Yongkang Liang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhishuang Wei
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jun Lv
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yongjin Cai
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiaobin Fan
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wenqing Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jie Chen
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Méndez-Maldonado K, Vega-López GA, Aybar MJ, Velasco I. Neurogenesis From Neural Crest Cells: Molecular Mechanisms in the Formation of Cranial Nerves and Ganglia. Front Cell Dev Biol 2020; 8:635. [PMID: 32850790 PMCID: PMC7427511 DOI: 10.3389/fcell.2020.00635] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/24/2020] [Indexed: 12/15/2022] Open
Abstract
The neural crest (NC) is a transient multipotent cell population that originates in the dorsal neural tube. Cells of the NC are highly migratory, as they travel considerable distances through the body to reach their final sites. Derivatives of the NC are neurons and glia of the peripheral nervous system (PNS) and the enteric nervous system as well as non-neural cells. Different signaling pathways triggered by Bone Morphogenetic Proteins (BMPs), Fibroblast Growth Factors (FGFs), Wnt proteins, Notch ligands, retinoic acid (RA), and Receptor Tyrosine Kinases (RTKs) participate in the processes of induction, specification, cell migration and neural differentiation of the NC. A specific set of signaling pathways and transcription factors are initially expressed in the neural plate border and then in the NC cell precursors to the formation of cranial nerves. The molecular mechanisms of control during embryonic development have been gradually elucidated, pointing to an important role of transcriptional regulators when neural differentiation occurs. However, some of these proteins have an important participation in malformations of the cranial portion and their mutation results in aberrant neurogenesis. This review aims to give an overview of the role of cell signaling and of the function of transcription factors involved in the specification of ganglia precursors and neurogenesis to form the NC-derived cranial nerves during organogenesis.
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Affiliation(s)
- Karla Méndez-Maldonado
- Instituto de Fisiología Celular - Neurociencias, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.,Departamento de Fisiología y Farmacología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Guillermo A Vega-López
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), San Miguel de Tucumán, Argentina.,Instituto de Biología "Dr. Francisco D. Barbieri", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina
| | - Manuel J Aybar
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), San Miguel de Tucumán, Argentina.,Instituto de Biología "Dr. Francisco D. Barbieri", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina
| | - Iván Velasco
- Instituto de Fisiología Celular - Neurociencias, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.,Laboratorio de Reprogramación Celular, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Ciudad de México, Mexico
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Gou X, Tang Y, Qu Y, Xiao D, Ying J, Mu D. Could the inhibitor of DNA binding 2 and 4 play a role in white matter injury? Rev Neurosci 2019; 30:625-638. [PMID: 30738015 DOI: 10.1515/revneuro-2018-0090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 11/02/2018] [Indexed: 01/12/2023]
Abstract
Abstract
White matter injury (WMI) prevents the normal development of myelination, leading to central nervous system myelination disorders and the production of chronic sequelae associated with WMI, such as chronic dyskinesia, cognitive impairment and cerebral palsy. This results in a large emotional and socioeconomic burden. Decreased myelination in preterm infant WMI is associated with the delayed development or destruction of oligodendrocyte (OL) lineage cells, particularly oligodendrocyte precursor cells (OPCs). The development of cells from the OL lineage involves the migration, proliferation and different stages of OL differentiation, finally leading to myelination. A series of complex intrinsic, extrinsic and epigenetic factors regulate the OPC cell cycle withdrawal, OL lineage progression and myelination. We focus on the inhibitor of DNA binding 2 (ID2), because it is widely involved in the different stages of OL differentiation and genesis. ID2 is a key transcription factor for the normal development of OL lineage cells, and the pathogenesis of WMI is closely linked with OL developmental disorders. ID4, another family member of the IDs protein, also plays a similar role in OL differentiation and genesis. ID2 and ID4 belong to the helix-loop-helix family; they lack the DNA-binding sequences and inhibit oligodendrogenesis and OPC differentiation. In this review, we mainly discuss the roles of ID2 in OL development, especially during OPC differentiation, and summarize the ID2-mediated intracellular and extracellular signaling pathways that regulate these processes. We also discuss ID4 in relation to bone morphogenetic protein signaling and oligodendrogenesis. It is likely that these developmental mechanisms are also involved in the myelin repair or remyelination in human neurological diseases.
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Affiliation(s)
- Xiaoyun Gou
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, China
- Key Laboratory of Obstetric and Gynecologic and Pediatric Diseases and Birth Defects, Ministry of Education, Sichuan University, Chengdu 610041, China
| | - Ying Tang
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, China
- Key Laboratory of Obstetric and Gynecologic and Pediatric Diseases and Birth Defects, Ministry of Education, Sichuan University, Chengdu 610041, China
| | - Yi Qu
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, China
- Key Laboratory of Obstetric and Gynecologic and Pediatric Diseases and Birth Defects, Ministry of Education, Sichuan University, Chengdu 610041, China
| | - Dongqiong Xiao
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, China
- Key Laboratory of Obstetric and Gynecologic and Pediatric Diseases and Birth Defects, Ministry of Education, Sichuan University, Chengdu 610041, China
| | - Junjie Ying
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, China
- Key Laboratory of Obstetric and Gynecologic and Pediatric Diseases and Birth Defects, Ministry of Education, Sichuan University, Chengdu 610041, China
| | - Dezhi Mu
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, China
- Key Laboratory of Obstetric and Gynecologic and Pediatric Diseases and Birth Defects, Ministry of Education, Sichuan University, Chengdu 610041, China
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Benayoun BA, Pollina EA, Ucar D, Mahmoudi S, Karra K, Wong ED, Devarajan K, Daugherty AC, Kundaje AB, Mancini E, Hitz BC, Gupta R, Rando TA, Baker JC, Snyder MP, Cherry JM, Brunet A. H3K4me3 breadth is linked to cell identity and transcriptional consistency. Cell 2014; 158:673-88. [PMID: 25083876 PMCID: PMC4137894 DOI: 10.1016/j.cell.2014.06.027] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 04/03/2014] [Accepted: 06/10/2014] [Indexed: 12/15/2022]
Abstract
Trimethylation of histone H3 at lysine 4 (H3K4me3) is a chromatin modification known to mark the transcription start sites of active genes. Here, we show that H3K4me3 domains that spread more broadly over genes in a given cell type preferentially mark genes that are essential for the identity and function of that cell type. Using the broadest H3K4me3 domains as a discovery tool in neural progenitor cells, we identify novel regulators of these cells. Machine learning models reveal that the broadest H3K4me3 domains represent a distinct entity, characterized by increased marks of elongation. The broadest H3K4me3 domains also have more paused polymerase at their promoters, suggesting a unique transcriptional output. Indeed, genes marked by the broadest H3K4me3 domains exhibit enhanced transcriptional consistency and [corrected] increased transcriptional levels, and perturbation of H3K4me3 breadth leads to changes in transcriptional consistency. Thus, H3K4me3 breadth contains information that could ensure transcriptional precision at key cell identity/function genes.
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Affiliation(s)
- Bérénice A Benayoun
- Department of Genetics, Stanford University, Stanford CA 94305, USA; Paul F. Glenn Laboratories for the Biology of Aging, Stanford University, Stanford CA 94305, USA
| | - Elizabeth A Pollina
- Department of Genetics, Stanford University, Stanford CA 94305, USA; Cancer Biology Program, Stanford University, Stanford CA 94305, USA
| | - Duygu Ucar
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Salah Mahmoudi
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Kalpana Karra
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Edith D Wong
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | | | | | - Anshul B Kundaje
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Elena Mancini
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Benjamin C Hitz
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Rakhi Gupta
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Thomas A Rando
- Paul F. Glenn Laboratories for the Biology of Aging, Stanford University, Stanford CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford CA 94305, USA; RR&D REAP, VA Palo Alto Health Care Systems, Palo Alto, CA 94304,USA
| | - Julie C Baker
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Michael P Snyder
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - J Michael Cherry
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Anne Brunet
- Department of Genetics, Stanford University, Stanford CA 94305, USA; Paul F. Glenn Laboratories for the Biology of Aging, Stanford University, Stanford CA 94305, USA; Cancer Biology Program, Stanford University, Stanford CA 94305, USA.
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Regadas I, Matos MR, Monteiro FA, Gómez-Skarmeta JL, Lima D, Bessa J, Casares F, Reguenga C. Several cis-regulatory elements control mRNA stability, translation efficiency, and expression pattern of Prrxl1 (paired related homeobox protein-like 1). J Biol Chem 2013; 288:36285-301. [PMID: 24214975 DOI: 10.1074/jbc.m113.491993] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The homeodomain transcription factor Prrxl1/DRG11 has emerged as a crucial molecule in the establishment of the pain circuitry, in particular spinal cord targeting of dorsal root ganglia (DRG) axons and differentiation of nociceptive glutamatergic spinal cord neurons. Despite Prrxl1 importance in the establishment of the DRG-spinal nociceptive circuit, the molecular mechanisms that regulate its expression along development remain largely unknown. Here, we show that Prrxl1 transcription is regulated by three alternative promoters (named P1, P2, and P3), which control the expression of three distinct Prrxl1 5'-UTR variants, named 5'-UTR-A, 5'-UTR-B, and 5'-UTR-C. These 5'-UTR sequences confer distinct mRNA stability and translation efficiency to the Prrxl1 transcript. The most conserved promoter (P3) contains a TATA-box and displays in vivo enhancer activity in a pattern that overlaps with the zebrafish Prrxl1 homologue, drgx. Regulatory modules present in this sequence were identified and characterized, including a binding site for Phox2b. Concomitantly, we demonstrate that zebrafish Phox2b is required for the expression of drgx in the facial, glossopharyngeal, and vagal cranial ganglia.
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Affiliation(s)
- Isabel Regadas
- From the Departamento de Biologia Experimental, Faculdade de Medicina do Porto, Universidade do Porto, Porto 4200-319, Portugal
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Webb AE, Pollina EA, Vierbuchen T, Urbán N, Ucar D, Leeman DS, Martynoga B, Sewak M, Rando TA, Guillemot F, Wernig M, Brunet A. FOXO3 shares common targets with ASCL1 genome-wide and inhibits ASCL1-dependent neurogenesis. Cell Rep 2013; 4:477-91. [PMID: 23891001 DOI: 10.1016/j.celrep.2013.06.035] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/11/2013] [Accepted: 06/25/2013] [Indexed: 12/16/2022] Open
Abstract
FOXO transcription factors are central regulators of longevity from worms to humans. FOXO3, the FOXO isoform associated with exceptional human longevity, preserves adult neural stem cell pools. Here, we identify FOXO3 direct targets genome-wide in primary cultures of adult neural progenitor cells (NPCs). Interestingly, FOXO3-bound sites are enriched for motifs for bHLH transcription factors, and FOXO3 shares common targets with the proneuronal bHLH transcription factor ASCL1/MASH1 in NPCs. Analysis of the chromatin landscape reveals that FOXO3 and ASCL1 are particularly enriched at the enhancers of genes involved in neurogenic pathways. Intriguingly, FOXO3 inhibits ASCL1-dependent neurogenesis in NPCs and direct neuronal conversion in fibroblasts. FOXO3 also restrains neurogenesis in vivo. Our study identifies a genome-wide interaction between the prolongevity transcription factor FOXO3 and the cell-fate determinant ASCL1 and raises the possibility that FOXO3's ability to restrain ASCL1-dependent neurogenesis may help preserve the neural stem cell pool.
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Affiliation(s)
- Ashley E Webb
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
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10
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Havrda MC, Paolella BR, Ward NM, Holroyd KB. Behavioral abnormalities and Parkinson's-like histological changes resulting from Id2 inactivation in mice. Dis Model Mech 2012; 6:819-27. [PMID: 23264561 PMCID: PMC3634664 DOI: 10.1242/dmm.010041] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Characterizing dopaminergic neuronal development and function in novel genetic animal models might uncover strategies for researchers to develop disease-modifying treatments for neurologic disorders. Id2 is a transcription factor expressed in the developing central nervous system. Id2(-/-) mice have fewer dopaminergic neurons in the olfactory bulb and reduced olfactory discrimination, a pre-clinical marker of Parkinson's disease. Here, we summarize behavioral, histological and in vitro molecular biological analyses to determine whether midbrain dopaminergic neurons are affected by Id2 loss. Id2(-/-) mice were hyperactive at 1 and 3 months of age, but by 6 months showed reduced activity. Id2(-/-) mice showed age-dependent histological alterations in dopaminergic neurons of the substantia nigra pars compacta (SNpC) associated with changes in locomotor activity. Reduced dopamine transporter (DAT) expression was observed at early ages in Id2(-/-) mice and DAT expression was dependent on Id2 expression in an in vitro dopaminergic differentiation model. Evidence of neurodegeneration, including activated caspase-3 and glial infiltration, were noted in the SNpC of older Id2(-/-) mice. These findings document a novel role for Id2 in the maintenance of midbrain dopamine neurons. The Id2(-/-) mouse should provide unique opportunities to study the progression of neurodegenerative disorders involving the dopamine system.
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Affiliation(s)
- Matthew C Havrda
- Norris Cotton Cancer Center and Department of Pediatrics, Geisel School of Medicine at Dartmouth, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.
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11
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Lessons from the embryonic neural stem cell niche for neural lineage differentiation of pluripotent stem cells. Stem Cell Rev Rep 2012; 8:813-29. [PMID: 22628111 PMCID: PMC3412081 DOI: 10.1007/s12015-012-9381-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Pluripotent stem cells offer an abundant and malleable source for the generation of differentiated cells for transplantation as well as for in vitro screens. Patterning and differentiation protocols have been developed to generate neural progeny from human embryonic or induced pluripotent stem cells. However, continued refinement is required to enhance efficiency and to prevent the generation of unwanted cell types. We summarize and interpret insights gained from studies of embryonic neuroepithelium. A multitude of factors including soluble molecules, interactions with the extracellular matrix and neighboring cells cooperate to control neural stem cell self-renewal versus differentiation. Applying these findings and concepts to human stem cell systems in vitro may yield more appropriately patterned cell types for biomedical applications.
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12
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Abstract
The intestine consists of epithelial cells that secrete digestive enzymes and mucus (gland cells), absorb food particles (enterocytes), and produce hormones (endocrine cells). Intestinal cells are rapidly turned over and need to be replaced. In cnidarians, mitosis of differentiated intestinal cells accounts for much of the replacement; in addition, migratory, multipotent stem cells (interstitial cells) contribute to the production of intestinal cells. In other phyla, intestinal cell replacement is solely the function of stem cells entering the gut from the outside (such as in case of the neoblasts of platyhelminths) or intestinal stem cells located within the midgut epithelium (as in both vertebrates or arthropods). We will attempt in the following to review important aspects of midgut stem cells in different animal groups: where are they located, what types of lineages do they produce, and how do they develop. We will start out with a comparative survey of midgut cell types found across the animal kingdom; then briefly look at the specification of these cells during embryonic development; and finally focus on the stem cells that regenerate midgut cells during adult life. In a number of model systems, including mouse, zebrafish and Drosophila, the molecular pathways controlling intestinal stem cells proliferation and the specification of intestinal cell types are under intensive investigation. We will highlight findings of the recent literature, focusing on aspects that are shared between the different models and that point at evolutionary ancient mechanisms of intestinal cell formation.
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Geist B, Vorwerk B, Coiro P, Ninnemann O, Nitsch R. PRG-1 transcriptional regulation independent from Nex1/Math2-mediated activation. Cell Mol Life Sci 2012; 69:651-61. [PMID: 21805347 PMCID: PMC11114846 DOI: 10.1007/s00018-011-0774-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 07/06/2011] [Accepted: 07/07/2011] [Indexed: 12/12/2022]
Abstract
Plasticity-related gene 1 (PRG-1) is a novel player in glutamatergic synaptic transmission, acting by interfering with lysophosphatidic acid (LPA)-dependent signaling pathways. In the central nervous system, PRG-1 expression is restricted to postsynaptic dendrites on glutamatergic neurons. In this study, we describe the promoter architecture of the PRG-1 gene using RNA ligase-mediated rapid amplification of cDNA ends (RLM-Race) and PCR analysis. We found that PRG-1 expression is under the control of a TATA-less promoter with multiple transcription start sites. We demonstrated also that 200-kb genomic environment of the PRG-1 gene is sufficient to mediate cell type-specific expression in a reporter mouse model. Characterization of the PRG-1 promoter resulted in the identification of a 450-bp sequence, mediating ≈40-fold enhancement of transcription in cultured primary neurons compared to controls, and which induced reporter expression in slice cultures in neurons. Recently, the regulation of PRG-1 by the basic helix-loop-helix transcription factor Nex1 (Math2, NeuroD6) was reported. However, our studies in Nex1-null-mice revealed that Nex1-deficiency induces no change in PRG-1 expression and localization. We detected an additional Nex1-independent regulation mechanism that increases PRG-1 expression and mediates neuron-specific expression in an organotypic environment.
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Affiliation(s)
- Beate Geist
- Institute for Microanatomy and Neurobiology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
- Present Address: Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité, Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Brita Vorwerk
- Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité, Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Pierluca Coiro
- Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité, Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Olaf Ninnemann
- Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité, Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Robert Nitsch
- Institute for Microanatomy and Neurobiology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
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14
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Takashima S, Adams KL, Ortiz PA, Ying CT, Moridzadeh R, Younossi-Hartenstein A, Hartenstein V. Development of the Drosophila entero-endocrine lineage and its specification by the Notch signaling pathway. Dev Biol 2011; 353:161-72. [PMID: 21382366 DOI: 10.1016/j.ydbio.2011.01.039] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/27/2011] [Accepted: 01/27/2011] [Indexed: 12/18/2022]
Abstract
In this paper we have investigated the developmental-genetic steps that shape the entero-endocrine system of Drosophila melanogaster from the embryo to the adult. The process starts in the endoderm of the early embryo where precursors of endocrine cells and enterocytes of the larval midgut, as well as progenitors of the adult midgut, are specified by a Notch signaling-dependent mechanism. In a second step that occurs during the late larval period, enterocytes and endocrine cells of a transient pupal midgut are selected from within the clusters of adult midgut progenitors. As in the embryo, activation of the Notch pathway triggers enterocyte differentiation and inhibits cells from further proliferation or choosing the endocrine fate. The third step of entero-endocrine cell development takes place at a mid-pupal stage. Before this time point, the epithelial layer destined to become the adult midgut is devoid of endocrine cells. However, precursors of the intestinal midgut stem cells (pISCs) are already present. After an initial phase of symmetric divisions which causes an increase in their own population size, pISCs start to spin off cells that become postmitotic and express the endocrine fate marker, Prospero. Activation of Notch in pISCs forces these cells into an enterocyte fate. Loss of Notch function causes an increase in the proliferatory activity of pISCs, as well as a higher ratio of Prospero-positive cells.
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Affiliation(s)
- Shigeo Takashima
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
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15
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Bunk EC, Stelzer S, Hermann S, Schäfers M, Schlatt S, Schwamborn JC. Cellular organization of adult neurogenesis in the Common Marmoset. Aging Cell 2011; 10:28-38. [PMID: 21040399 DOI: 10.1111/j.1474-9726.2010.00639.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Adult neurogenesis within the subgranular zone (SGZ) of the hippocampal dentate gyrus and the subventricular zone (SVZ) of the lateral ventricle (LV) has been most intensely studied within the brains of rodents such as mice and rats. However, little is known about the cell types and processes involved in adult neurogenesis within primates such as the common marmoset (Callithrix jacchus). Moreover, substantial differences seem to exist between the neurogenic niche of the LV between rodents and humans. Here, we set out to use immunohistochemical and autogradiographic analysis to characterize the anatomy of the neurogenic niches and the expression of cell type-specific markers in those niches in the adult common marmoset brain. Moreover, we demonstrate significant differences in the activity of neurogenesis in the adult marmoset brain compared to the adult mouse brain. Finally, we provide evidence for ongoing proliferation of neuroblasts within both the SGZ and SVZ of the adult brain and further show that the age-dependent decline of neurogenesis in the hippocampus is associated with a decrease in neuroblast cells.
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Affiliation(s)
- Eva C Bunk
- ZMBE, Cell Biology, Stem Cell Biology and Regeneration Group, Germany
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16
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Hartenstein V, Takashima S, Adams KL. Conserved genetic pathways controlling the development of the diffuse endocrine system in vertebrates and Drosophila. Gen Comp Endocrinol 2010; 166:462-9. [PMID: 20005229 PMCID: PMC3950663 DOI: 10.1016/j.ygcen.2009.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 12/04/2009] [Indexed: 11/26/2022]
Abstract
The midgut epithelium is formed by absorptive enterocytes, secretory cells and endocrine cells. Each of these lineages is derived from the pluripotent progenitors that constitute the embryonic endoderm; the mature midgut retains pools of self-renewing stem cells that continue to produce all lineages. Recent findings in vertebrates and Drosophila shed light on the genetic mechanism that specifies the fate of the different lineages. A pivotal role is played by the Notch signaling pathway that, in a manner that appears to be very similar to the way in which Notch signaling selects neural progenitors within the neurectoderm, distinguishes the fate of secretory/endocrine cells and enterocytes. Proneural genes encoding bHLH transcription factors are expressed and required in prospective endocrine cells; activation of the Notch pathways restricts the number of these cells and promotes enterocyte development. In this review we compare the development of the intestinal endocrine cells in vertebrates and insects and summarize recent findings dealing with genetic pathways controlling this cell type.
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Affiliation(s)
- Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA.
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17
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Aguado-Llera D, Goormaghtigh E, de Geest N, Quan XJ, Prieto A, Hassan BA, Gómez J, Neira JL. The basic helix-loop-helix region of human neurogenin 1 is a monomeric natively unfolded protein which forms a "fuzzy" complex upon DNA binding. Biochemistry 2010; 49:1577-89. [PMID: 20102160 DOI: 10.1021/bi901616z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neuronal specification is regulated by the activity of transcription factors containing the basic helix-loop-helix motif (bHLH); these regulating proteins include, among others, the neurogenin (Ngn) family, related to the atonal family of genes. Neurogenin 1 (NGN1) is a 237-residue protein that contains a bHLH domain and is involved in neuronal differentiation. In this work, we synthesized the bHLH region of NGN1 (bHLHN) comprising residues 90-150 of the full-length NGN1. The domain is a monomeric natively unfolded protein with a pH-dependent premolten globule conformation, as shown by several spectroscopic techniques (namely, NMR, fluorescence, FTIR, and circular dichroism). The unfolded character of the domain also explains, first, the impossibility of its overexpression in several Escherichia coli strains and, second, its insolubility in aqueous buffers. To the best of our knowledge, this is the first extensive study of the conformational preferences of a bHLH domain under different solution conditions. Upon binding to two DNA E-boxes, the protein forms "fuzzy" complexes (that is, the complexes were not fully folded). The affinities of bHLHN for both DNA boxes were smaller than those of other bHLH domains, which might explain why the protein-DNA complexes were not fully folded.
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Affiliation(s)
- David Aguado-Llera
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche (Alicante), Spain
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18
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Eun B, Cho B, Moon Y, Kim SY, Kim K, Kim H, Sun W. Induction of neuronal apoptosis by expression of Hes6 via p53-dependent pathway. Brain Res 2009; 1313:1-8. [PMID: 19968968 DOI: 10.1016/j.brainres.2009.11.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 11/23/2009] [Accepted: 11/30/2009] [Indexed: 01/22/2023]
Abstract
Hes6 is a member of hairy/enhancer of split (Hes) family that plays a role in the cell proliferation and differentiation. Recently, we found that Hes6 is involved in the regulation of cell proliferation via p53-dependent pathway. In addition to the proliferating regions, brain regions where early post-mitotic neurons are enriched also exhibited Hes6 and p53 mRNA expression. Because p53 is involved in the post-mitotic neuronal apoptosis, here we investigated whether Hes6 can influence the neuronal survival/death. Overexpression of wild-type Hes6 and its mutants induced the apoptosis of primary cultured cortical neurons. In addition, neuronal apoptosis by Hes6 overexpression was markedly blunted in p53(-/-) or Bax(-/-) cortical neurons, suggesting that these pro-apoptotic effects are mediated by p53- and Bax-dependent pathway. However, transactivation-defective mutants of Hes6 also enhanced neuronal apoptosis, suggesting that apoptogenic activity of Hes6 is not directly related to its role in the transcriptional regulation. We propose that Hes6 may play a significant role in the neuronal cell death and/or pathological neurodegeneration via activation of p53 signaling.
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Affiliation(s)
- Bokkee Eun
- Department of Anatomy, Brain Korea 21, Korea University College of Medicine, Seoul, Korea
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19
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Chiu SC, Hung HS, Lin SZ, Chiang E, Liu DD. Therapeutic potential of olfactory ensheathing cells in neurodegenerative diseases. J Mol Med (Berl) 2009; 87:1179-89. [PMID: 19756447 DOI: 10.1007/s00109-009-0528-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 08/17/2009] [Accepted: 08/26/2009] [Indexed: 12/28/2022]
Abstract
The regenerative capacity of the olfactory system has generated interest in potential clinical application of cells from the olfactory epithelium in the treatment of neurodegenerative diseases. Experimental evidence from animal models and clinical studies suggest that transplantation of olfactory ensheathing cells (OEC), specialized glia in the olfactory system, may be therapeutically useful in neurodegenerative diseases such as spinal cord injury and stroke. This review article describes the different experimental approaches in OEC transplantation. We also discuss the possible effects of OEC implantation on the underlying pathophysiology in neurological disease, including neuroplasticity. Our recent study of this particular population of cells has disclosed some of the molecular basis of the regenerative mechanism of OECs. In summary OECs produce several neurotrophic factors such as stromal cell-derived factor 1alpha and brain-derived neurotrophic factor and enhance axonal regeneration to promote neuroplasticity in neurodegenerative diseases.
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Affiliation(s)
- Shao-Chih Chiu
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan
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20
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Kuwabara T, Hsieh J, Muotri A, Yeo G, Warashina M, Lie DC, Moore L, Nakashima K, Asashima M, Gage FH. Wnt-mediated activation of NeuroD1 and retro-elements during adult neurogenesis. Nat Neurosci 2009; 12:1097-105. [PMID: 19701198 DOI: 10.1038/nn.2360] [Citation(s) in RCA: 474] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 05/22/2009] [Indexed: 01/15/2023]
Abstract
In adult hippocampus, new neurons are continuously generated from neural stem cells (NSCs), but the molecular mechanisms regulating adult neurogenesis remain elusive. We found that Wnt signaling, together with the removal of Sox2, triggered the expression of NeuroD1 in mice. This transcriptional regulatory mechanism was dependent on a DNA element containing overlapping Sox2 and T-cell factor/lymphoid enhancer factor (TCF/LEF)-binding sites (Sox/LEF) in the promoter. Notably, Sox/LEF sites were also found in long interspersed nuclear element 1 (LINE-1) elements, consistent with their critical roles in the transition of NSCs to proliferating neuronal progenitors. Our results describe a previously unknown Wnt-mediated regulatory mechanism that simultaneously coordinates activation of NeuroD1 and LINE-1, which is important for adult neurogenesis and survival of neuronal progenitors. Moreover, the discovery that LINE-1 retro-elements embedded in the mammalian genome can function as bi-directional promoters suggests that Sox/LEF regulatory sites may represent a general mechanism, at least in part, for relaying environmental signals to other nearby loci to promote adult hippocampal neurogenesis.
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Affiliation(s)
- Tomoko Kuwabara
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Science City, Japan.
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21
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He F, Wen HS, Dong SL, Shi B, Chen CF, Wang LS, Yao J, Mu XJ, Zhou YG. Polymorphisms within promoter of Japanese flounder (Paralichthys olivaceus) ovary cytochrome P450-c19 (CYP19a) gene associated with reproductive traits. FISH PHYSIOLOGY AND BIOCHEMISTRY 2009; 35:333-340. [PMID: 19578940 DOI: 10.1007/s10695-008-9237-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 05/17/2008] [Indexed: 05/28/2023]
Abstract
Cytochrome P450 aromatase, which is encoded by the CYP19a gene, converts androgens to estradiol. Considerable evidence suggests that estrogens play an important role in fish reproductive process. Therefore CYP19a is an excellent candidate gene for reproductive traits. Variants in the promoter of the CYP19a gene might also be involved in the control of aromatase expression and affect regulatory mechanism linking cholesterol metabolism to the synthesis of sex steroids. In this study, nine single-nucleotide polymorphisms (SNPs) were detected with polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP), namely A-680G, G-672A, AGTAGT-649 inserting or deleting, T-623C, C-410A, T7-454A, T-402C, TTTCCAGACTGA-345 inserting or deleting, and G-297C. Nine SNPs within the promoter of the CYP19a gene were tested for association with four reproductive traits [serum testosterone (T), serum 17beta-estradiol (E(2)), hepatosomatic index (HSI), and gonadosomatic index (GSI)] in a population of 50 female Japanese flounder individuals. A locus, P3 (TTTCCAGACTGA-345 inserting or deleting, G-297C), was significantly associated with 17beta-estradiol (E(2)) level (P < 0.05) in female Japanese flounder. In addition, there was significant association between one diplotype based on nine SNPs and reproductive trait. The genetic effect for E(2) level of diplotype D3 was significantly higher than those of other diplotypes (P < 0.05). Results indicate that these genetic effects of those variants on E(2) level may help to explain CYP19a gene status in the reproductive endocrinology of Japanese flounder.
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Affiliation(s)
- Feng He
- Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, 266003, People's Republic of China
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22
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Id2 is required for specification of dopaminergic neurons during adult olfactory neurogenesis. J Neurosci 2009; 28:14074-86. [PMID: 19109490 DOI: 10.1523/jneurosci.3188-08.2008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Understanding the biology of adult neural stem cells has important implications for nervous system development and may contribute to our understanding of neurodegenerative disorders and their treatment. We have characterized the process of olfactory neurogenesis in adult mice lacking inhibitor of DNA binding 2(-/-) (Id2(-/-)). We found a diminished olfactory bulb containing reduced numbers of granular and periglomerular neurons with a distinct paucity of dopaminergic periglomerular neurons. While no deficiency of the stem cell compartment was detectable, migrating neuroblasts in Id2(-/-) mutant mice prematurely undergo astroglial differentiation within a disorganized rostral migratory stream. Further, when evaluated in vitro loss of Id2 results in decreased proliferation of neural progenitors and decreased expression of the Hes1 and Ascl1 (Mash1) transcription factors, known mediators of neuronal differentiation. These data support a novel role for sustained Id2 expression in migrating neural progenitors mediating olfactory dopaminergic neuronal differentiation in adult animals.
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23
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Abstract
In human most cortical gamma-aminobutyric acidergic (GABAergic) neurons are produced in the proliferative zones of the dorsal telencephalon in contrast to rodents. We report that in cynomolgus monkey fetuses cortical GABAergic neurons are generated in the proliferative zones of the dorsal telencephalon, in addition to the proliferative region of the ventral telencephalon, the ganglionic eminence (GE), however, with a temporal delay. GABAergic neuron progenitors labeled for Mash1 and GAD65 were present mainly in the GE at embryonic days (E) 47-55, and in the entire dorsal telencephalon at E64-75. These progenitors within the dorsal telencephalon are generated locally rather than in the GE. The ventral and dorsal lineages of cortical GABAergic neurons display different laminar distribution. Early generated GABAergic neurons from the GE mostly populate the marginal zone and subplate, whereas cortical plate GABAergic neurons originate from both ventral and dorsal telencephalon. A differential regulation of the two GABA synthesizing enzymes (GAD65 and GAD67) parallels GABAergic neuron differentiation. GAD65 is preferentially expressed in GABAergic progenitors and migrating neurons, GAD67 in morphologically differentiated neurons. Therefore, the dorsal telencephalic origin of cortical GABAergic neurons is not human-specific but appears as a former event in the ascent of evolution that could provide GABAergic neurons to an expending neocortex.
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Affiliation(s)
- Zdravko Petanjek
- Institut National de la Santé et de la Recherche Médicale U29, INMED, Marseille, F-13009 France
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Brigitte Berger
- CNRS, UMR8189, Université Paris Descartes, Laboratoire de Psychologie et Neurosciences Cognitives, Institut de Psychologie, Boulogne Billancourt F-92774, France
| | - Monique Esclapez
- Institut National de la Santé et de la Recherche Médicale U29, INMED, Marseille, F-13009 France
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24
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Aerts S, Vilain S, Hu S, Tranchevent LC, Barriot R, Yan J, Moreau Y, Hassan BA, Quan XJ. Integrating computational biology and forward genetics in Drosophila. PLoS Genet 2009; 5:e1000351. [PMID: 19165344 PMCID: PMC2628282 DOI: 10.1371/journal.pgen.1000351] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 12/19/2008] [Indexed: 11/18/2022] Open
Abstract
Genetic screens are powerful methods for the discovery of gene-phenotype associations. However, a systems biology approach to genetics must leverage the massive amount of "omics" data to enhance the power and speed of functional gene discovery in vivo. Thus far, few computational methods for gene function prediction have been rigorously tested for their performance on a genome-wide scale in vivo. In this work, we demonstrate that integrating genome-wide computational gene prioritization with large-scale genetic screening is a powerful tool for functional gene discovery. To discover genes involved in neural development in Drosophila, we extend our strategy for the prioritization of human candidate disease genes to functional prioritization in Drosophila. We then integrate this prioritization strategy with a large-scale genetic screen for interactors of the proneural transcription factor Atonal using genomic deficiencies and mutant and RNAi collections. Using the prioritized genes validated in our genetic screen, we describe a novel genetic interaction network for Atonal. Lastly, we prioritize the whole Drosophila genome and identify candidate gene associations for ten receptor-signaling pathways. This novel database of prioritized pathway candidates, as well as a web application for functional prioritization in Drosophila, called Endeavour-HighFly, and the Atonal network, are publicly available resources. A systems genetics approach that combines the power of computational predictions with in vivo genetic screens strongly enhances the process of gene function and gene-gene association discovery.
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Affiliation(s)
- Stein Aerts
- Laboratory of Neurogenetics, Department of Molecular and Developmental Genetics, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Department of Human Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
| | - Sven Vilain
- Laboratory of Neurogenetics, Department of Molecular and Developmental Genetics, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Department of Human Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
- Doctoral Program in Molecular and Developmental Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
| | - Shu Hu
- Laboratory of Neurogenetics, Department of Molecular and Developmental Genetics, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Department of Human Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
- Doctoral Program in Molecular and Developmental Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
| | | | - Roland Barriot
- Department of Electrical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jiekun Yan
- Laboratory of Neurogenetics, Department of Molecular and Developmental Genetics, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Department of Human Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
| | - Yves Moreau
- Department of Electrical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Bassem A. Hassan
- Laboratory of Neurogenetics, Department of Molecular and Developmental Genetics, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Department of Human Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
- Doctoral Program in Molecular and Developmental Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
| | - Xiao-Jiang Quan
- Laboratory of Neurogenetics, Department of Molecular and Developmental Genetics, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Department of Human Genetics, Katholieke Universiteit Leuven School of Medicine, Leuven, Belgium
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25
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Willardsen MI, Suli A, Pan Y, Marsh-Armstrong N, Chien CB, El-Hodiri H, Brown NL, Moore KB, Vetter ML. Temporal regulation of Ath5 gene expression during eye development. Dev Biol 2008; 326:471-81. [PMID: 19059393 DOI: 10.1016/j.ydbio.2008.10.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2008] [Revised: 10/29/2008] [Accepted: 10/30/2008] [Indexed: 12/11/2022]
Abstract
During central nervous system development the timing of progenitor differentiation must be precisely controlled to generate the proper number and complement of neuronal cell types. Proneural basic helix-loop-helix (bHLH) transcription factors play a central role in regulating neurogenesis, and thus the timing of their expression must be regulated to ensure that they act at the appropriate developmental time. In the developing retina, the expression of the bHLH factor Ath5 is controlled by multiple signals in early retinal progenitors, although less is known about how these signals are coordinated to ensure correct spatial and temporal pattern of gene expression. Here we identify a key distal Xath5 enhancer and show that this enhancer regulates the early phase of Xath5 expression, while the proximal enhancer we previously identified acts later. The distal enhancer responds to Pax6, a key patterning factor in the optic vesicle, while FGF signaling regulates Xath5 expression through sequences outside of this region. In addition, we have identified an inhibitory element adjacent to the conserved distal enhancer region that is required to prevent premature initiation of expression in the retina. This temporal regulation of Xath5 gene expression is comparable to proneural gene regulation in Drosophila, whereby separate enhancers regulate different temporal phases of expression.
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Affiliation(s)
- Minde I Willardsen
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
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26
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Shyu WC, Liu DD, Lin SZ, Li WW, Su CY, Chang YC, Wang HJ, Wang HW, Tsai CH, Li H. Implantation of olfactory ensheathing cells promotes neuroplasticity in murine models of stroke. J Clin Invest 2008; 118:2482-95. [PMID: 18596986 DOI: 10.1172/jci34363] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 04/16/2008] [Indexed: 12/22/2022] Open
Abstract
Murine olfactory ensheathing cells (OECs) promote central nervous system axonal regeneration in models of spinal cord injury. We investigated whether OECs could induce a neuroplastic effect to improve the neurological dysfunction caused by hypoxic/ischemic stress. In this study, human OECs/olfactory nerve fibroblasts (hOECs/ONFs) specifically secreted trophic factors including stromal cell-derived factor-1alpha (SDF-1alpha). Rats with intracerebral hOEC/ONF implantation showed more improvement on behavioral measures of neurological deficit following stroke than control rats. [18F]fluoro-2-deoxyglucose PET (FDG-PET) showed increased glucose metabolic activity in the hOEC/ONF-treated group compared with controls. In mice, transplanted hOECs/ONFs and endogenous homing stem cells including intrinsic neural progenitor cells and bone marrow stem cells colocalized with specific neural and vascular markers, indicating stem cell fusion. Both hOECs/ONFs and endogenous homing stem cells enhanced neuroplasticity in the rat and mouse ischemic brain. Upregulation of SDF-1alpha and CXCR4 in hOECs/ONFs promoted neurite outgrowth of cocultured primary cortical neurons under oxygen glucose deprivation conditions and in stroke animals through upregulation of cellular prion protein (PrP C) expression. Therefore, the upregulation of SDF-1alpha and the enhancement of CXCR4 and PrP C interaction induced by hOEC/ONF implantation mediated neuroplastic signals in response to hypoxia and ischemia.
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Affiliation(s)
- Woei-Cherng Shyu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Republic of China
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27
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Zordan P, Croci L, Hawkes R, Consalez GG. Comparative analysis of proneural gene expression in the embryonic cerebellum. Dev Dyn 2008; 237:1726-35. [PMID: 18498101 DOI: 10.1002/dvdy.21571] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The embryonic cerebellum contains two germinative epithelia: the rhombic lip and the ventricular zone. While the lineage of glutamatergic neurons arising from the rhombic lip has been characterized, plenty remains to be learned about the factors giving rise to the array of ventricular zone-derived gamma-aminobutyric acid (GABA)ergic neurons. In the present study, we describe the expression of proneural genes Mash1/Ascl1, Ngn1/Neurog1, and Ngn2/Neurog2 in the cerebellar primordium at key stages of Purkinje cell and interneuron development, and compare them with the expression of other genes active in the same context. Our results indicate that Ngn1, Ngn2 and Mash1 are expressed at relevant stages of cerebellar neurogenesis in the prospective cerebellar nuclei and in the ventricular zone, excluding the Math1/Atoh1-positive rhombic lip. Their expression domains are only partially overlapping, suggesting that they may contribute selectively to ventricular zone regionalization, giving rise to the diversity of cerebellar GABA neurons and, possibly, Purkinje cell subtypes.
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Affiliation(s)
- Paola Zordan
- San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
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Maintaining epitheliopoietic potency when culturing olfactory progenitors. Exp Neurol 2008; 214:25-36. [PMID: 18703052 DOI: 10.1016/j.expneurol.2008.07.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 05/23/2008] [Accepted: 07/03/2008] [Indexed: 11/22/2022]
Abstract
The olfactory epithelium is remarkable for the persistence of multipotent, neurocompetent progenitor and stem cells throughout life that can replace all of the various cell types of the epithelium following injury. The therapeutic exploitation of the neurocompetent stem cells of the adult olfactory epithelium would be facilitated by the development of a culture system that maintains the in vivo potency of the progenitors while they are expanded and/or manipulated. We have used an air-liquid interface culture protocol, in which a feeder cell layer of 3T3 cells is established on the underside of a culture insert and Facs-isolated or unsorted progenitor cells from the methyl bromide-lesioned adult rodent epithelium are seeded on upper side. Under these conditions, epithelial cells other than HBCs are capable of organizing themselves into complex three-dimensional, epithelium-lined spheres, which can be passaged. The spheres contain cells with the molecular phenotype of globose basal cells, horizontal basal cells, sustentacular cells and neurons. Spheres derived from mice that express the green fluorescent protein constitutively can be dissociated after 6 days in vitro and directly transplanted into the epithelium of wild-type, methyl bromide-lesioned mice via nasal infusion. The resulting clones contain the various cell types observed in aggregate when globose basal cells are transplanted acutely. In contrast, the same cells cultured as two-dimensional, submerged cultures undergo fibroblastic transition after transplantation and do not integrate into the epithelium. In conclusion, the culture system described here maintains the potency of progenitors, which can then participate in epitheliopoiesis in vivo.
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Lynn FC, Sanchez L, Gomis R, German MS, Gasa R. Identification of the bHLH factor Math6 as a novel component of the embryonic pancreas transcriptional network. PLoS One 2008; 3:e2430. [PMID: 18560595 PMCID: PMC2413403 DOI: 10.1371/journal.pone.0002430] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 05/07/2008] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Basic helix-loop-helix (bHLH) transcription factors play important roles in differentiation processes during embryonic development of vertebrates. In the pancreas, the atonal-related bHLH gene Neurogenin3 (Neurog3) controls endocrine cell fate specification in uncommitted progenitor cells. Therefore, it is likely that Neurog3-regulated factors will have important functions during pancreatic endocrine cell differentiation. The gene for the atonal-related bHLH factor Math6 was recognized as a potential target of Neurog3 in a genomic scale profiling during endocrine differentiation. Herein we have explored the role of Math6 during endocrine pancreas development. RESULTS We demonstrate that the Math6 gene is a direct target of Neurog3 in vitro and that, during mouse development, Math6 is expressed in both endocrine and exocrine pancreatic precursor cells. We have investigated the role of Math6 in endocrine differentiation by over-expressing this factor in pancreatic duct cells. Math6 possesses intrinsic transcriptional repressor activity and, in contrast to Neurog3 it does not induce the endocrine differentiation program; however, it can modulate some of the pro-endocrine functions of Neurog3 in this system. In addition, we show that Math6 is broadly expressed in mouse embryonic tissues and its expression is induced by tissue-specific bHLH genes other than Neurog3. Furthermore, inactivation of the Math6 gene in the mouse results in early embryonic lethality demonstrating an essential role of this factor in organismal development. CONCLUSIONS These data demonstrate that Math6 is a novel component of the pancreatic transcriptional network during embryonic development and suggest a potential role for Math6 as a modulator of the differentiation program initiated by the pro-endocrine factor Neurog3. Furthermore, our results demonstrate that Math6 is indispensable for early embryonic development and indicate a more widespread function for this factor in tissue-specific differentiation processes that are dependent on class II bHLH genes.
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Affiliation(s)
- Francis C. Lynn
- Diabetes Center, Hormone Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Lidia Sanchez
- Diabetes and Obesity Laboratory-Endocrinology and Nutrition Unit, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)-Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Ramon Gomis
- Diabetes and Obesity Laboratory-Endocrinology and Nutrition Unit, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)-Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Michael S. German
- Diabetes Center, Hormone Research Institute, University of California San Francisco, San Francisco, California, United States of America
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Rosa Gasa
- Diabetes and Obesity Laboratory-Endocrinology and Nutrition Unit, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)-Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
- * E-mail:
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Misra K, Mishra K, Gui H, Matise MP. Prox1 regulates a transitory state for interneuron neurogenesis in the spinal cord. Dev Dyn 2008; 237:393-402. [PMID: 18213584 DOI: 10.1002/dvdy.21422] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Proper central nervous system (CNS) function depends critically on the generation of functionally distinct neuronal types in specific and reproducible positions. The generation of neuronal diversity during CNS development involves a fine balance between dividing neural progenitors and the differentiated neuronal progeny that they produce. However, the molecular mechanisms that regulate these processes are still poorly understood. Here, we show that the Prox1 transcription factor, which is expressed transiently and specifically in spinal interneurons, plays an important role in neurogenesis. Using both gain- and loss-of-function approaches, we find that Prox1 is capable of driving neuronal precursors out of the cell cycle and can initiate limited expression of neuronal proteins. Using RNAi approaches, we show that Prox1 function is required to execute a neurogenic differentiation program downstream of Mash1 and Ngn2. Our studies demonstrate an important, spinal interneuron-specific role for Prox1 in controlling steps required for both cell-cycle withdrawal and differentiation.
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Affiliation(s)
- Kamana Misra
- Robert Wood Johnson Medical School, UMDNJ, Piscataway, New Jersey 08854, USA
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Chow ESH, Hui MNY, Lin CC, Cheng SH. Cadmium inhibits neurogenesis in zebrafish embryonic brain development. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2008; 87:157-169. [PMID: 18342959 DOI: 10.1016/j.aquatox.2008.01.019] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 01/17/2008] [Accepted: 01/25/2008] [Indexed: 05/26/2023]
Abstract
Cadmium is a non-essential heavy metal found abundantly in the environment. Children of women exposed to cadmium during pregnancy display lower motor and perceptual abilities. High cadmium body burden in children is also related to impaired intelligence and lowered school achievement. However, little is known about the molecular and cellular basis of developmental neurotoxicity in the sensitive early life stages of animals. In this study, we explore neurological deficits caused by cadmium during early embryonic stages in zebrafish by examining regionalization of the neural tube, pattern formation and cell fate determination, commitment of proneural genes and induction of neurogenesis. We show that cadmium-treated embryos developed a smaller head with unclear boundaries between the brain subdivisions, particularly in the mid-hindbrain region. Embryos display normal anterior to posterior regionalization; however, the commitment of neural progenitor cells was affected by cadmium. We observe prominent reductions in the expression of several proneuronal genes including ngn1 in cell clusters, zash1a in the developing optic tectum, and zash1b in the telencephalon and tectum. Cadmium-treated embryos also have fewer differentiated neurons and glia in the facial sensory ganglia as indicated by decreased zn-12 expression. Also, a lower transcription level of neurogenic genes, ngn1 and neuroD, is observed in neurons. Our data suggest that cadmium-induced neurotoxicity can be caused by impaired neurogenesis, resulting in markedly reduced neuronal differentiation and axonogenesis.
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Affiliation(s)
- Elly Suk Hen Chow
- Division of Biology, California Institute of Technology, 1200 California Boulevard, Pasadena, CA 91125, USA
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Nakazaki H, Reddy AC, Mania-Farnell BL, Shen YW, Ichi S, McCabe C, George D, McLone DG, Tomita T, Mayanil CSK. Key basic helix-loop-helix transcription factor genes Hes1 and Ngn2 are regulated by Pax3 during mouse embryonic development. Dev Biol 2008; 316:510-23. [PMID: 18308300 DOI: 10.1016/j.ydbio.2008.01.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 01/08/2008] [Accepted: 01/09/2008] [Indexed: 11/20/2022]
Abstract
Pax3 is expressed early during embryonic development in spatially restricted domains including limb muscle, neural crest, and neural tube. Pax3 functions at the nodal point in melanocyte stem cell differentiation, cardiogenesis and neurogenesis. Additionally Pax3 has been implicated in migration and differentiation of precursor cell populations. Currently there are questions about how Pax3 regulates these diverse functions. In this study we found that in the absence of functional Pax3, as in Splotch embryos, the neural crest cells undergo premature neurogenesis, as evidenced by increased Brn3a positive staining in neural tube explants, in comparison with wild-type. Premature neurogenesis in the absence of functional Pax3 may be due to a change in the regulation of basic helix-loop-helix transcription factors implicated in proliferation and differentiation. Using promoter-luciferase activity measurements in transient co-transfection experiments and electro-mobility shift assays, we show that Pax3 regulates Hairy and enhancer of split homolog-1 (Hes1) and Neurogenin2 (Ngn2) by directly binding to their promoters. Chromatin immunoprecipitation assays confirmed that Pax3 bound to cis-regulatory elements within Hes1 and Ngn2 promoters. These observations suggest that Pax3 regulates Hes1 and Ngn2 and imply that it may couple migration with neural stem cell maintenance and neurogenesis.
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Affiliation(s)
- Hiromichi Nakazaki
- Laboratory for Neural Tube Research, Developmental Biology Program, Children's Memorial Research Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA
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Asai S, Yamaki A, Kudoh J, Shimizu N, Shimizu Y. Analysis of the promoter region of human placenta-specific DSCR4 gene. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2007; 1779:40-50. [PMID: 18086574 DOI: 10.1016/j.bbagrm.2007.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 09/09/2007] [Accepted: 09/14/2007] [Indexed: 11/27/2022]
Abstract
The gene DSCR4 locates in the band q22.2 of human chromosome 21 and encodes a protein of 118 amino acids. Expression of DSCR4 is restricted to human placenta and placental choriocarcinoma cell lines BeWo and JEG3. The 5'-RACE method using RNA from human placenta indicated the major transcription start site at 93 nt upstream (nt -93) of the initiation codon. Transfection assay using a series of deletion constructs of the 5'-flanking region fused to the luciferase reporter gene identified three positive regions nt -2200 to -2088, nt -2064 to -1924, nt -810 to -632 and two negative regions nt -1923 to -1740, nt -631 to -425. The computer analysis predicted the presence of several cis-elements in these regions and the promoter assay using various mutants of consensus sequence identified two distinct cis-elements for OLF-1 and E47. The electrophoretic mobility shift assay (EMSA) using the extracts of DSCR4-expressing cells confirmed the binding of certain protein factors to these cis-elements. In fact, OLF-1-like transcription factor, EBF-3 and EBF-4 were detected in the DSCR4-expressing cell lines and human placenta. Based on these data, we postulated that transcription of DSCR4 gene is regulated positively by binding of OLF-1-like transcription factor and negatively by binding of E47-like transcription factor.
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Affiliation(s)
- Satoko Asai
- Department of Medical Genetics, School of Health Sciences, Kyorin University, 476, Miyashita-cho, Hachioji-shi, Tokyo 192-8508, Japan
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De Preter K, Vandesompele J, Heimann P, Yigit N, Beckman S, Schramm A, Eggert A, Stallings RL, Benoit Y, Renard M, Paepe AD, Laureys G, Påhlman S, Speleman F. Human fetal neuroblast and neuroblastoma transcriptome analysis confirms neuroblast origin and highlights neuroblastoma candidate genes. Genome Biol 2007; 7:R84. [PMID: 16989664 PMCID: PMC1794547 DOI: 10.1186/gb-2006-7-9-r84] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 08/17/2006] [Accepted: 09/21/2006] [Indexed: 11/25/2022] Open
Abstract
Transcriptome profiling of neuroblasts and neuroblastoma tumor cells provides strong support for a neuroblast origin of neuroblastoma and highlights new candidate neuroblastoma genes Background Neuroblastoma tumor cells are assumed to originate from primitive neuroblasts giving rise to the sympathetic nervous system. Because these precursor cells are not detectable in postnatal life, their transcription profile has remained inaccessible for comparative data mining strategies in neuroblastoma. This study provides the first genome-wide mRNA expression profile of these human fetal sympathetic neuroblasts. To this purpose, small islets of normal neuroblasts were isolated by laser microdissection from human fetal adrenal glands. Results Expression of catecholamine metabolism genes, and neuronal and neuroendocrine markers in the neuroblasts indicated that the proper cells were microdissected. The similarities in expression profile between normal neuroblasts and malignant neuroblastomas provided strong evidence for the neuroblast origin hypothesis of neuroblastoma. Next, supervised feature selection was used to identify the genes that are differentially expressed in normal neuroblasts versus neuroblastoma tumors. This approach efficiently sifted out genes previously reported in neuroblastoma expression profiling studies; most importantly, it also highlighted a series of genes and pathways previously not mentioned in neuroblastoma biology but that were assumed to be involved in neuroblastoma pathogenesis. Conclusion This unique dataset adds power to ongoing and future gene expression studies in neuroblastoma and will facilitate the identification of molecular targets for novel therapies. In addition, this neuroblast transcriptome resource could prove useful for the further study of human sympathoadrenal biogenesis.
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Affiliation(s)
- Katleen De Preter
- Center for Medical Genetics, Ghent University Hospital, De Pintelaan, B-9000 Ghent, Belgium
| | - Jo Vandesompele
- Center for Medical Genetics, Ghent University Hospital, De Pintelaan, B-9000 Ghent, Belgium
| | - Pierre Heimann
- Department of Medical Genetics, University Hospital Erasme, Lenniksebaan, B-1070 Brussels, Belgium
| | - Nurten Yigit
- Center for Medical Genetics, Ghent University Hospital, De Pintelaan, B-9000 Ghent, Belgium
| | - Siv Beckman
- Division of Molecular Medicine, Department of Laboratory Medicine, Lund University, University Hospital MAS, SE-20502 Malmö, Sweden
| | - Alexander Schramm
- Department of Pediatric Oncology and Hematology, University Hospital of Essen, Hufelandstr, Essen 45122, Germany
| | - Angelika Eggert
- Department of Pediatric Oncology and Hematology, University Hospital of Essen, Hufelandstr, Essen 45122, Germany
| | - Raymond L Stallings
- Children's Cancer Research Institute, University of Texas Health Science Center, Floyd Curl Drive, Mail Code 7784, San Antonio, Texas 78229-3900, USA
| | - Yves Benoit
- Department of Pediatrics, Ghent University Hospital, De Pintelaan, B-9000 Ghent, Belgium
| | - Marleen Renard
- Department of Pediatrics, UZ Gasthuisberg, Herestraat, B-3000 Leuven, Belgium
| | - Anne De Paepe
- Center for Medical Genetics, Ghent University Hospital, De Pintelaan, B-9000 Ghent, Belgium
| | - Geneviève Laureys
- Department of Pediatrics, Ghent University Hospital, De Pintelaan, B-9000 Ghent, Belgium
| | - Sven Påhlman
- Division of Molecular Medicine, Department of Laboratory Medicine, Lund University, University Hospital MAS, SE-20502 Malmö, Sweden
| | - Frank Speleman
- Center for Medical Genetics, Ghent University Hospital, De Pintelaan, B-9000 Ghent, Belgium
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Nguyen L, Borgs L, Vandenbosch R, Mangin JM, Beukelaers P, Moonen G, Gallo V, Malgrange B, Belachew S. The Yin and Yang of cell cycle progression and differentiation in the oligodendroglial lineage. ACTA ACUST UNITED AC 2006; 12:85-96. [PMID: 16807909 DOI: 10.1002/mrdd.20103] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In white matter disorders such as leukodystrophies (LD), periventricular leucomalacia (PVL), or multiple sclerosis (MS), the hypomyelination or the remyelination failure by oligodendrocyte progenitor cells involves errors in the sequence of events that normally occur during development when progenitors proliferate, migrate through the white matter, contact the axon, and differentiate into myelin-forming oligodendrocytes. Multiple mechanisms underlie the eventual progressive deterioration that typifies the natural history of developmental demyelination in LD and PVL and of adult-onset demyelination in MS. Over the past few years, pathophysiological studies have mostly focused on seeking abnormalities that impede oligodendroglial maturation at the level of migration, myelination, and survival. In contrast, there has been a strikingly lower interest for early proliferative and differentiation events that are likely to be equally critical for white matter development and myelin repair. This review highlights the Yin and Yang principles of interactions between intrinsic factors that coordinately regulate progenitor cell division and the onset of differentiation, i.e. the initial steps of oligodendrocyte lineage progression that are obviously crucial in health and diseases.
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Affiliation(s)
- Laurent Nguyen
- Developmental Neurobiology Unit, Center for Cellular and Molecular Neuroscience, University of Liège, C.H.U. Sart Tilman, B36, 4000 Liège, Belgium
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Guimera J, Weisenhorn DV, Wurst W. Megane/Heslike is required for normal GABAergic differentiation in the mouse superior colliculus. Development 2006; 133:3847-57. [PMID: 16968817 DOI: 10.1242/dev.02557] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The mouse Mgn protein (Helt) is structurally related to the neurogenic Drosophila hairy and Enhancer of split [h/E(spl)]proteins, but its unique structural properties distinguish it from other members of the family. Mgn expression shows a spatiotemporal correlation with GABAergic markers in several brain regions. We report here that homozygous Mgn-null mice die between the second and the fifth postnatal week of age, and show a complete depletion of Gad65 and Gad67 expression in the superior colliculus and a reduction in the inferior colliculus. Other brain regions, as well as other neural systems, are not affected. The progenitor GABAergic cells appear to be generated in right numbers but fail to become GABAergic neurons. The phenotype of the mice is consistent with reduced GABAergic activity. Thus, our in vivo study provides evidence that Mgn is the key regulator of GABAergic neurons, controlling their specification in the dorsal midbrain. Another conclusion from our results is that the function of Mgn shows a previously unrecognized role for h/E(spl)-related transcription factors in the dorsal midbrain GABAergic cell differentiation. Vertebrate h/E(spl)-related genes can no longer be regarded solely as a factors that confer generic neurogenic properties, but as key components for the subtype-neuronal identity in the mammalian CNS.
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Affiliation(s)
- Jordi Guimera
- GSF-National Research Center for Environment and Health, Institute of Developmental Genetics, 35/8006, Ingolstädter Landstrasse, 1, Neuherberg, Germany.
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Wang C, Bian W, Xia C, Zhang T, Guillemot F, Jing N. Visualization of bHLH transcription factor interactions in living mammalian cell nuclei and developing chicken neural tube by FRET. Cell Res 2006; 16:585-98. [PMID: 16775630 DOI: 10.1038/sj.cr.7310076] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Members of the basic helix-loop-helix (bHLH) gene family play important roles in vertebrate neurogenesis. In this study, confocal microscopy-based fluorescence resonance energy transfer (FRET) is used to monitor bHLH protein-protein interactions under various physiological conditions. Tissue-specific bHLH activators, NeuroD1, Mash1, Neurogenin1 (Ngn1), Neurogenin2 (Ngn2), and ubiquitous expressed E47 protein are tagged with enhanced yellow fluorescence protein (EYFP) and enhanced cyan fluorescence protein (ECFP), respectively. The subcellular localization and mobility of bHLH fusion proteins are examined in HEK293 cells. By transient transfection and in ovo electroporation, four pairs of tissue-specific bHLH activators and E47 protein are over-expressed in HEK293 cells and developing chick embryo neural tube. With the acceptor photobleaching method, FRET could be detected between these bHLH protein pairs in the nuclei of transfected cells and developing neural tubes. Mash1/E47 and Ngn2/E47 FRET pairs show higher FRET efficiencies in the medial and the lateral half of chick embryo neural tube, respectively. It suggests that these bHLH protein pairs formed functional DNA-protein complexes with regulatory elements of their downstream target genes in the specific regions. This work will help one understand the behaviours of bHLH factors in vivo.
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Affiliation(s)
- Chen Wang
- Key Laboratory of Stem Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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Bradley CK, Takano EA, Hall MA, Göthert JR, Harvey AR, Begley CG, van Eekelen JAM. The essential haematopoietic transcription factor Scl is also critical for neuronal development. Eur J Neurosci 2006; 23:1677-89. [PMID: 16623824 DOI: 10.1111/j.1460-9568.2006.04712.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract The basic helix-loop-helix (bHLH) transcription factor Scl displays tissue-restricted expression and is critical for the establishment of the haematopoietic system; loss of Scl results in embryonic death due to absolute anaemia. Scl is also expressed in neurons of the mouse diencephalon, mesencephalon and metencephalon; however, its requirement in those sites remains to be determined. Here we report conditional deletion of Scl in neuronal precursor cells using the Cre/LoxP system. Neuronal-Scl deleted mice died prematurely, were growth retarded and exhibited an altered motor phenotype characterized by hyperactivity and circling. Moreover, ablation of Scl in the nervous system affected brain morphology with abnormal neuronal development in brain regions known to express Scl under normal circumstances; there was an almost complete absence of Scl-null neurons in the hindbrain and partial loss of Scl-null neurons in the thalamus and midbrain from early neurogenesis onwards. Our results demonstrate a crucial role for Scl in the development of Scl-expressing neurons, including gamma-aminobutyric acid (GABA)ergic interneurons. Our study represents one of the first demonstrations of functional overlap of a single bHLH protein that regulates neural and haematopoietic cell development. This finding underlines Scl's critical function in cell fate determination of mesodermal as well as neuroectodermal tissues.
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Affiliation(s)
- Cara K Bradley
- Telethon Institute for Child Health Research and Centre for Child Health Research at the University of Western Australia, Subiaco WA 6008, Australia
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Yang X, Tomita T, Wines-Samuelson M, Beglopoulos V, Tansey MG, Kopan R, Shen J. Notch1 signaling influences v2 interneuron and motor neuron development in the spinal cord. Dev Neurosci 2006; 28:102-17. [PMID: 16508308 DOI: 10.1159/000090757] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 06/21/2005] [Indexed: 12/21/2022] Open
Abstract
The Notch signaling pathway plays a variety of roles in cell fate decisions during development. Previous studies have shown that reduced Notch signaling results in premature differentiation of neural progenitor cells, while increased Notch activities promote apoptotic death of neural progenitor cells in the developing brain. Whether Notch signaling is involved in the specification of neuronal subtypes is unclear. Here we examine the role of Notch1 in the development of neuronal subtypes in the spinal cord using conditional knockout (cKO) mice lacking Notch1 specifically in neural progenitor cells. Notch1 inactivation results in accelerated neuronal differentiation in the ventral spinal cord and gradual disappearance of the ventral central canal. These changes are accompanied by reduced expression of Hes1 and Hes5 and increased expression of Mash1 and Neurogenin 1 and 2. Using markers (Nkx2.2, Nkx6.1, Olig2, Pax6 and Dbx1) for one or multiple progenitor cell types, we found reductions of all subtypes of progenitor cells in the ventral spinal cord of Notch1 cKO mice. Similarly, using markers (Islet1/2, Lim3, Sim1, Chox10, En1 and Evx1/2) specific for motor neurons and distinct classes of interneurons, we found increases in the number of V0-2 interneurons in the ventral spinal cord of Notch1 cKO mice. Specifically, the number of Lim3+/Chox10+ V2 interneurons is markedly increased while the number of Lim3+/Islet+motor neurons is decreased in the Notch1 cKO spinal cord, suggesting that V2 interneurons are generated at the expense of motor neurons in the absence of Notch1. These results provide support for a role of Notch1 in neuronal subtype specification in the ventral spinal cord.
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Affiliation(s)
- Xudong Yang
- Center for Neurologic Diseases, Brigham and Women's Hospital, Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
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Gaughwin PM, Caldwell MA, Anderson JM, Schwiening CJ, Fawcett JW, Compston DAS, Chandran S. Astrocytes promote neurogenesis from oligodendrocyte precursor cells. Eur J Neurosci 2006; 23:945-56. [PMID: 16519659 DOI: 10.1111/j.1460-9568.2006.04625.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The oligodendrocyte precursor cell (OPC) has until recently been regarded as a lineage-restricted precursor cell. Considerable interest has been generated by reports suggesting that OPCs may possess a wider differentiation potential than previously assumed and thus be considered a multipotential stem cell. This study examined the neuronal differentiation potential of rat, postnatal cortical OPCs in response to extracellular cues in vitro and in vivo. OPCs did not exhibit intrinsic neuronal potential and were restricted to oligodendrocyte lineage potential following treatment with the neural precursor mitogen fibroblast growth factor 2. In contrast, a postnatal hippocampal astrocyte-derived signal(s) is sufficient to induce functional neuronal differentiation of cortical OPCs in vitro in population and single cell studies. Co-treatment with Noggin, a bone morphogenetic protein antagonist, did not attenuate neuronal differentiation. Following transplantation to the adult rat hippocampus, cortical OPCs expressed doublecortin, a neuroblast-associated marker. The present findings show that hippocampal, astrocyte-derived signals can induce the neuronal differentiation of OPCs through a Noggin-independent mechanism.
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Affiliation(s)
- P M Gaughwin
- Department of Clinical Neurosciences and Centre for Brain Repair, Forvie Site, Robinson Way, Cambridge CB2 2PY, UK
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41
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Schlosser G. Induction and specification of cranial placodes. Dev Biol 2006; 294:303-51. [PMID: 16677629 DOI: 10.1016/j.ydbio.2006.03.009] [Citation(s) in RCA: 282] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Revised: 12/22/2005] [Accepted: 12/23/2005] [Indexed: 12/17/2022]
Abstract
Cranial placodes are specialized regions of the ectoderm, which give rise to various sensory ganglia and contribute to the pituitary gland and sensory organs of the vertebrate head. They include the adenohypophyseal, olfactory, lens, trigeminal, and profundal placodes, a series of epibranchial placodes, an otic placode, and a series of lateral line placodes. After a long period of neglect, recent years have seen a resurgence of interest in placode induction and specification. There is increasing evidence that all placodes despite their different developmental fates originate from a common panplacodal primordium around the neural plate. This common primordium is defined by the expression of transcription factors of the Six1/2, Six4/5, and Eya families, which later continue to be expressed in all placodes and appear to promote generic placodal properties such as proliferation, the capacity for morphogenetic movements, and neuronal differentiation. A large number of other transcription factors are expressed in subdomains of the panplacodal primordium and appear to contribute to the specification of particular subsets of placodes. This review first provides a brief overview of different cranial placodes and then synthesizes evidence for the common origin of all placodes from a panplacodal primordium. The role of various transcription factors for the development of the different placodes is addressed next, and it is discussed how individual placodes may be specified and compartmentalized within the panplacodal primordium. Finally, tissues and signals involved in placode induction are summarized with a special focus on induction of the panplacodal primordium itself (generic placode induction) and its relation to neural induction and neural crest induction. Integrating current data, new models of generic placode induction and of combinatorial placode specification are presented.
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Affiliation(s)
- Gerhard Schlosser
- Brain Research Institute, AG Roth, University of Bremen, FB2, 28334 Bremen, Germany.
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Bulfone A, Carotenuto P, Faedo A, Aglio V, Garzia L, Bello AM, Basile A, Andrè A, Cocchia M, Guardiola O, Ballabio A, Rubenstein JLR, Zollo M. Telencephalic embryonic subtractive sequences: a unique collection of neurodevelopmental genes. J Neurosci 2006; 25:7586-600. [PMID: 16107646 PMCID: PMC6725394 DOI: 10.1523/jneurosci.0522-05.2005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The vertebrate telencephalon is composed of many architectonically and functionally distinct areas and structures, with billions of neurons that are precisely connected. This complexity is fine-tuned during development by numerous genes. To identify genes involved in the regulation of telencephalic development, a specific subset of differentially expressed genes was characterized. Here, we describe a set of cDNAs encoded by genes preferentially expressed during development of the mouse telencephalon that was identified through a functional genomics approach. Of 832 distinct transcripts found, 223 (27%) are known genes. Of the remaining, 228 (27%) correspond to expressed sequence tags of unknown function, 58 (7%) are homologs or orthologs of known genes, and 323 (39%) correspond to novel rare transcripts, including 48 (14%) new putative noncoding RNAs. As an example of this latter group of novel precursor transcripts of micro-RNAs, telencephalic embryonic subtractive sequence (TESS) 24.E3 was functionally characterized, and one of its targets was identified: the zinc finger transcription factor ZFP9. The TESS transcriptome has been annotated, mapped for chromosome loci, and arrayed for its gene expression profiles during neural development and differentiation (in Neuro2a and neural stem cells). Within this collection, 188 genes were also characterized on embryonic and postnatal tissue by in situ hybridization, demonstrating that most are specifically expressed in the embryonic CNS. The full information has been organized into a searchable database linked to other genomic resources, allowing easy access to those who are interested in the dissection of the molecular basis of telencephalic development.
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Affiliation(s)
- Alessandro Bulfone
- Stem Cell Research Institute-Hospital San Raffaele, Istituto Scientifico San Raffaele, 20132 Milan, Italy.
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43
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Kele J, Simplicio N, Ferri ALM, Mira H, Guillemot F, Arenas E, Ang SL. Neurogenin 2 is required for the development of ventral midbrain dopaminergic neurons. Development 2006; 133:495-505. [PMID: 16410412 DOI: 10.1242/dev.02223] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Proneural genes are crucial regulators of neurogenesis and subtype specification in many areas of the nervous system; however, their function in dopaminergic neuron development is unknown. We report that proneural genes have an intricate pattern of expression in the ventricular zone of the ventral midbrain, where mesencephalic dopaminergic neurons are generated. Neurogenin 2(Ngn2) and Mash1 are expressed in the ventral midline, while Ngn1, Ngn2 and Mash1 are co-localized more laterally in the ventricular zone. Ngn2 is also expressed in an intermediate zone immediately adjacent to the ventricular zone at the ventral midline. To examine the function of these genes, we analyzed mutant mice in which one or two of these genes were deleted (Ngn1, Ngn2 and Mash1) or substituted (Mash1 in the Ngn2 locus). Our results demonstrate that Ngn2 is required for the differentiation of Sox2+ ventricular zone progenitors into Nurr1+postmitotic dopaminergic neuron precursors in the intermediate zone, and that it is also likely to be required for their subsequent differentiation into tyrosine hydroxylase-positive dopaminergic neurons in the marginal zone. Although Mash1 normally has no detectable function in dopaminergic neuron development, it could partially rescue the generation of dopaminergic neuron precursors in the absence of Ngn2. These results demonstrate that Ngn2 is uniquely required for the development of midbrain dopaminergic neurons.
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Affiliation(s)
- Julianna Kele
- Laboratory of Molecular Neurobiology, MBB, Karolinska Institutet, Retzius building A1, Stockholm, Sweden
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44
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Schlosser G. Development and evolution of lateral line placodes in amphibians I. Development. ZOOLOGY 2006; 105:119-46. [PMID: 16351862 DOI: 10.1078/0944-2006-00058] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2002] [Accepted: 05/30/2002] [Indexed: 11/18/2022]
Abstract
Lateral line placodes are specialized regions of the ectoderm that give rise to the receptor organs of the lateral line system as well as to the sensory neurons innervating them. The development of lateral line placodes has been studied in amphibians since the early 1900s. This paper reviews these older studies and tries to integrate them with more recent findings. Lateral line placodes are probably induced in a multistep process from a panplacodal area surrounding the neural plate. The time schedule of these inductive processes has begun to be unravelled, but little is known yet about their molecular basis. Subsequent pattern formation, morphogenesis and differentiation of lateral line placodes proceeds in most respects relatively autonomously: Onset and polarity of migration of lateral line primordia, the type, spacing, size and number of receptor organs formed, as well as the patterned differentiation of different cell types occur normally even in ectopic locations. Only the pathways for migration of lateral line primordia depend on external cues. Thus, lateral line placodes act as integrated and relatively context-insensitive developmental modules.
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Schlosser G. Evolutionary origins of vertebrate placodes: insights from developmental studies and from comparisons with other deuterostomes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2005; 304:347-99. [PMID: 16003766 DOI: 10.1002/jez.b.21055] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ectodermal placodes comprise the adenohypophyseal, olfactory, lens, profundal, trigeminal, otic, lateral line, and epibranchial placodes. The first part of this review presents a brief overview of placode development. Placodes give rise to a variety of cell types and contribute to many sensory organs and ganglia of the vertebrate head. While different placodes differ with respect to location and derivative cell types, all appear to originate from a common panplacodal primordium, induced at the anterior neural plate border by a combination of mesodermal and neural signals and defined by the expression of Six1, Six4, and Eya genes. Evidence from mouse and zebrafish mutants suggests that these genes promote generic placodal properties such as cell proliferation, cell shape changes, and specification of neurons. The common developmental origin of placodes suggests that all placodes may have evolved in several steps from a common precursor. The second part of this review summarizes our current knowledge of placode evolution. Although placodes (like neural crest cells) have been proposed to be evolutionary novelties of vertebrates, recent studies in ascidians and amphioxus have proposed that some placodes originated earlier in the chordate lineage. However, while the origin of several cellular and molecular components of placodes (e.g., regionalized expression domains of transcription factors and some neuronal or neurosecretory cell types) clearly predates the origin of vertebrates, there is presently little evidence that these components are integrated into placodes in protochordates. A scenario is presented according to which all placodes evolved from an adenohypophyseal-olfactory protoplacode, which may have originated in the vertebrate ancestor from the anlage of a rostral neurosecretory organ (surviving as Hatschek's pit in present-day amphioxus).
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Brugmann SA, Moody SA. Induction and specification of the vertebrate ectodermal placodes: precursors of the cranial sensory organs. Biol Cell 2005; 97:303-19. [PMID: 15836430 DOI: 10.1042/bc20040515] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The sensory organs of the vertebrate head derive from two embryological structures, the neural crest and the ectodermal placodes. Although quite a lot is known about the secreted and transcription factors that regulate neural crest development, until recently little was known about the molecular pathways that regulate placode development. Herein we review recent findings on the induction and specification of the pre-placodal ectoderm, and the transcription factors that are involved in regulating placode fate and initial differentiation.
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Affiliation(s)
- Samantha A Brugmann
- Department of Anatomy and Cell Biology, Genetics Program, The George Washington University, Washington, DC, USA
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Hutcheson DA, Hanson MI, Moore KB, Le TT, Brown NL, Vetter ML. bHLH-dependent and -independent modes of Ath5 gene regulation during retinal development. Development 2005; 132:829-39. [PMID: 15677728 DOI: 10.1242/dev.01653] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a wide range of vertebrate species, the bHLH transcription factor Ath5 is tightly associated with both the initiation of neurogenesis in the retina and the genesis of retinal ganglion cells. Here, we describe at least two modes of regulating the expression of Ath5 during retinal development. We have found that a proximal cis-regulatory region of the Xenopus Ath5 gene (Xath5) is highly conserved across vertebrate species and is sufficient to drive retinal-specific reporter gene expression in transgenic Xenopus embryos. Xath5 proximal transgene expression depended upon two highly conserved bHLH factor binding sites (E-boxes) as well as bHLH factor activity in vivo. However, we found that bHLH activity was not required for expression of a longer Xath5 transgene, suggesting that additional mechanisms contribute to Xath5 expression in vivo. Consistent with this, we showed that a more distal fragment that does not include the conserved proximal region is sufficient to promote transgene expression in the developing retina. In mouse, we found that a longer fragment of the cis-regulatory region of either the mouse or Xenopus Ath5 gene was necessary for transgene expression, and that expression of a mouse Math5 (Atoh7) transgene was not dependent upon autoregulation. Thus, despite extensive conservation in the proximal region, the importance of these elements may be species dependent.
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Affiliation(s)
- David A Hutcheson
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
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Hofstetter CP, Holmström NAV, Lilja JA, Schweinhardt P, Hao J, Spenger C, Wiesenfeld-Hallin Z, Kurpad SN, Frisén J, Olson L. Allodynia limits the usefulness of intraspinal neural stem cell grafts; directed differentiation improves outcome. Nat Neurosci 2005; 8:346-53. [PMID: 15711542 DOI: 10.1038/nn1405] [Citation(s) in RCA: 480] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Accepted: 01/21/2005] [Indexed: 12/23/2022]
Abstract
Several studies have reported functional improvement after transplantation of neural stem cells into injured spinal cord. We now provide evidence that grafting of adult neural stem cells into a rat thoracic spinal cord weight-drop injury improves motor recovery but also causes aberrant axonal sprouting associated with allodynia-like hypersensitivity of forepaws. Transduction of neural stem cells with neurogenin-2 before transplantation suppressed astrocytic differentiation of engrafted cells and prevented graft-induced sprouting and allodynia. Transduction with neurogenin-2 also improved the positive effects of engrafted stem cells, including increased amounts of myelin in the injured area, recovery of hindlimb locomotor function and hindlimb sensory responses, as determined by functional magnetic resonance imaging. These findings show that stem cell transplantation into injured spinal cord can cause severe side effects and call for caution in the consideration of clinical trials.
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Abstract
Caenorhabditis elegans motor neurons control a range of activities including locomotion, foraging, defecation, and gender-specific functions. In this chapter,we focus primarily on motor neurons that regulate body movement, with particular emphasis on those in the ventral nerve cord (VNC). We describe the basic architecture and development of the motor circuit, genes that specify motor neuron fates, and models of how the motor circuit controls locomotion. We identify surprising similarities between the structure and development of the nematode and vertebrate axial nerve cords and speculate about the potential roles of conserved families of transcription factors in the evolution of these motor circuits.
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Affiliation(s)
- Stephen E Von Stetina
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
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50
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Manglapus GL, Youngentob SL, Schwob JE. Expression patterns of basic helix-loop-helix transcription factors define subsets of olfactory progenitor cells. J Comp Neurol 2004; 479:216-33. [PMID: 15452857 DOI: 10.1002/cne.20316] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Direct damage to the olfactory epithelium by inhalation of the olfactotoxin methyl bromide activates a population of multipotent globose basal cells, which reconstitute all depleted cell populations. Because members of the basic helix-loop-helix family of transcription factors are known to regulate neurogenesis and cell production, we performed in situ hybridization to examine the expression of several members of that family during the recovery of the rat olfactory epithelium after methyl bromide lesion. The numbers of basal cells expressing the proneural transcriptional activators Mash1, Neurogenin1, and NeuroD all fall precipitously 1 day after lesion. Mash1 levels begin to recover by 2 days, Neurogenin1 and NeuroD by 3 days, and substantial numbers of neurons reappear by 4 days. The antineurogenic factor Hes1 is limited to the sustentacular cells of the unlesioned olfactory epithelium and to the adjoining respiratory epithelium. Immediately after methyl bromide lesion, but not at any time after bulbectomy, a large fraction of residual, marker-confirmed globose basal cells initiate expression of Hes1. Subsequently, the Hes1-positive cells lose their association with the basal lamina, shift apically, and differentiate into sustentacular cells. In contrast, Hes5 is expressed by a small subset of globose basal cells and by olfactory ensheathing glia in the normal mucosa; Hes5 label disappears from both transiently after lesion. In sum, the recovery of the neuronal population after peripheral lesion recapitulates the sequence of transcription factor expression observed during embryonic development of the epithelium. Moreover, expression of Hes1 marks that population of globose basal cells committed to making sustentacular cells after methyl bromide lesion.
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Affiliation(s)
- Glen L Manglapus
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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