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Zhang X, Leavey P, Appel H, Makrides N, Blackshaw S. Molecular mechanisms controlling vertebrate retinal patterning, neurogenesis, and cell fate specification. Trends Genet 2023; 39:736-757. [PMID: 37423870 PMCID: PMC10529299 DOI: 10.1016/j.tig.2023.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 07/11/2023]
Abstract
This review covers recent advances in understanding the molecular mechanisms controlling neurogenesis and specification of the developing retina, with a focus on insights obtained from comparative single cell multiomic analysis. We discuss recent advances in understanding the mechanisms by which extrinsic factors trigger transcriptional changes that spatially pattern the optic cup (OC) and control the initiation and progression of retinal neurogenesis. We also discuss progress in unraveling the core evolutionarily conserved gene regulatory networks (GRNs) that specify early- and late-state retinal progenitor cells (RPCs) and neurogenic progenitors and that control the final steps in determining cell identity. Finally, we discuss findings that provide insight into regulation of species-specific aspects of retinal patterning and neurogenesis, including consideration of key outstanding questions in the field.
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Affiliation(s)
- Xin Zhang
- Department of Ophthalmology, Columbia University School of Medicine, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University School of Medicine, New York, NY, USA.
| | - Patrick Leavey
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Haley Appel
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Neoklis Makrides
- Department of Ophthalmology, Columbia University School of Medicine, New York, NY, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Psychiatry and Behavioral Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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2
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Jones AA, Willoner Jr. T, Mishoe Hernandez L, DeLaurier A. Exposure to valproic acid (VPA) reproduces hdac1 loss of function phenotypes in zebrafish. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000908. [PMID: 37829572 PMCID: PMC10565572 DOI: 10.17912/micropub.biology.000908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 10/14/2023]
Abstract
Histone deacetylases are enzymes that remove acetyl groups from histone tails and are understood to act as repressors of transcriptional activity. Hdac1 has been previously shown to function in eye, pectoral fin, heart, liver, and pharyngeal skeletal development. We show that high doses of Valproic Acid (VPA) reproduce the hdac1 phenotype. We identify tbx5 genes as potential targets of Hdac1 in eye, pectoral fin, and heart development. Using timed exposures, we show that skeletal structures in the pharyngeal arches are impacted by VPA between 24-36 hours post-fertilization, indicating a role for Hdac1 during post-migration patterning, differentiation, or proliferation of cranial neural crest cells.
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Affiliation(s)
- Alec A. Jones
- Biology and Geology, University of South Carolina Aiken, Aiken, South Carolina, United States
| | - Terence Willoner Jr.
- Biology and Geology, University of South Carolina Aiken, Aiken, South Carolina, United States
| | - Lacie Mishoe Hernandez
- Biology and Geology, University of South Carolina Aiken, Aiken, South Carolina, United States
| | - April DeLaurier
- Biology and Geology, University of South Carolina Aiken, Aiken, South Carolina, United States
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3
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Takata N, Miska JM, Morgan MA, Patel P, Billingham LK, Joshi N, Schipma MJ, Dumar ZJ, Joshi NR, Misharin AV, Embry RB, Fiore L, Gao P, Diebold LP, McElroy GS, Shilatifard A, Chandel NS, Oliver G. Lactate-dependent transcriptional regulation controls mammalian eye morphogenesis. Nat Commun 2023; 14:4129. [PMID: 37452018 PMCID: PMC10349100 DOI: 10.1038/s41467-023-39672-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 06/26/2023] [Indexed: 07/18/2023] Open
Abstract
Mammalian retinal metabolism favors aerobic glycolysis. However, the role of glycolytic metabolism in retinal morphogenesis remains unknown. We report that aerobic glycolysis is necessary for the early stages of retinal development. Taking advantage of an unbiased approach that combines the use of eye organoids and single-cell RNA sequencing, we identify specific glucose transporters and glycolytic genes in retinal progenitors. Next, we determine that the optic vesicle territory of mouse embryos displays elevated levels of glycolytic activity. At the functional level, we show that removal of Glucose transporter 1 and Lactate dehydrogenase A gene activity from developing retinal progenitors arrests eye morphogenesis. Surprisingly, we uncover that lactate-mediated upregulation of key eye-field transcription factors is controlled by the epigenetic modification of histone H3 acetylation through histone deacetylase activity. Our results identify an unexpected bioenergetic independent role of lactate as a signaling molecule necessary for mammalian eye morphogenesis.
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Affiliation(s)
- Nozomu Takata
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 E. Superior Street, Chicago, IL, 60611, USA
| | - Jason M Miska
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Marc A Morgan
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Priyam Patel
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Leah K Billingham
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Neha Joshi
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Matthew J Schipma
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Zachary J Dumar
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Nikita R Joshi
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Alexander V Misharin
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Ryan B Embry
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Luciano Fiore
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
- Laboratory of Nanomedicine, National Atomic Energy Commission (CNEA), Av. General Paz 1499, B1650KNA, San Martín, Buenos Aires, Argentina
| | - Peng Gao
- Robert H. Lurie Cancer Center Metabolomics Core, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Lauren P Diebold
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Gregory S McElroy
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Navdeep S Chandel
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Guillermo Oliver
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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4
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Musolf AM, Haarman AEG, Luben RN, Ong JS, Patasova K, Trapero RH, Marsh J, Jain I, Jain R, Wang PZ, Lewis DD, Tedja MS, Iglesias AI, Li H, Cowan CS, Biino G, Klein AP, Duggal P, Mackey DA, Hayward C, Haller T, Metspalu A, Wedenoja J, Pärssinen O, Cheng CY, Saw SM, Stambolian D, Hysi PG, Khawaja AP, Vitart V, Hammond CJ, van Duijn CM, Verhoeven VJM, Klaver CCW, Bailey-Wilson JE. Rare variant analyses across multiethnic cohorts identify novel genes for refractive error. Commun Biol 2023; 6:6. [PMID: 36596879 PMCID: PMC9810640 DOI: 10.1038/s42003-022-04323-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/30/2022] [Indexed: 01/05/2023] Open
Abstract
Refractive error, measured here as mean spherical equivalent (SER), is a complex eye condition caused by both genetic and environmental factors. Individuals with strong positive or negative values of SER require spectacles or other approaches for vision correction. Common genetic risk factors have been identified by genome-wide association studies (GWAS), but a great part of the refractive error heritability is still missing. Some of this heritability may be explained by rare variants (minor allele frequency [MAF] ≤ 0.01.). We performed multiple gene-based association tests of mean Spherical Equivalent with rare variants in exome array data from the Consortium for Refractive Error and Myopia (CREAM). The dataset consisted of over 27,000 total subjects from five cohorts of Indo-European and Eastern Asian ethnicity. We identified 129 unique genes associated with refractive error, many of which were replicated in multiple cohorts. Our best novel candidates included the retina expressed PDCD6IP, the circadian rhythm gene PER3, and P4HTM, which affects eye morphology. Future work will include functional studies and validation. Identification of genes contributing to refractive error and future understanding of their function may lead to better treatment and prevention of refractive errors, which themselves are important risk factors for various blinding conditions.
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Affiliation(s)
- Anthony M Musolf
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Annechien E G Haarman
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Robert N Luben
- MRC Epidemiology, University of Cambridge School of Clinical Medicine, Cambridge, UK
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Jue-Sheng Ong
- Statistical Genetics Laboratory, Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Karina Patasova
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Rolando Hernandez Trapero
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Joseph Marsh
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Ishika Jain
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Riya Jain
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Paul Zhiping Wang
- Institute for Biomedical Sciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Deyana D Lewis
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Milly S Tedja
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Adriana I Iglesias
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Hengtong Li
- Data Science Unit, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Cameron S Cowan
- Institute for Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
| | - Ginevra Biino
- Institute of Molecular Genetics, National Research Council of Italy, Pavia, Italy
| | - Alison P Klein
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Priya Duggal
- The Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia
| | - Caroline Hayward
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Toomas Haller
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Andres Metspalu
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Juho Wedenoja
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Department of Public Health, University of Helsinki, Helsinki, Finland
| | - Olavi Pärssinen
- Department of Ophthalmology, Central Hospital of Central Finland, Jyväskylä, Finland
- Gerontology Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Ching-Yu Cheng
- Centre for Quantitative Medicine, DUKE-National University of Singapore, Singapore, Singapore
- Ocular Epidemiology Research Group, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Seang-Mei Saw
- Saw Swee Hock School of Public Health, National University Health Systems, National University of Singapore, Singapore, Singapore
- Myopia Research Group, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Dwight Stambolian
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Pirro G Hysi
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Anthony P Khawaja
- MRC Epidemiology, University of Cambridge School of Clinical Medicine, Cambridge, UK
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Veronique Vitart
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Christopher J Hammond
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | | | - Virginie J M Verhoeven
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.
| | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Institute for Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.
- Department of Ophthalmology, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Joan E Bailey-Wilson
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA.
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5
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Al-Khindi T, Sherman MB, Kodama T, Gopal P, Pan Z, Kiraly JK, Zhang H, Goff LA, du Lac S, Kolodkin AL. The transcription factor Tbx5 regulates direction-selective retinal ganglion cell development and image stabilization. Curr Biol 2022; 32:4286-4298.e5. [PMID: 35998637 PMCID: PMC9560999 DOI: 10.1016/j.cub.2022.07.064] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/05/2022] [Accepted: 07/21/2022] [Indexed: 12/14/2022]
Abstract
The diversity of visual input processed by the mammalian visual system requires the generation of many distinct retinal ganglion cell (RGC) types, each tuned to a particular feature. The molecular code needed to generate this cell-type diversity is poorly understood. Here, we focus on the molecules needed to specify one type of retinal cell: the upward-preferring ON direction-selective ganglion cell (up-oDSGC) of the mouse visual system. Single-cell transcriptomic profiling of up- and down-oDSGCs shows that the transcription factor Tbx5 is selectively expressed in up-oDSGCs. The loss of Tbx5 in up-oDSGCs results in a selective defect in the formation of up-oDSGCs and a corresponding inability to detect vertical motion. A downstream effector of Tbx5, Sfrp1, is also critical for vertical motion detection but not up-oDSGC formation. These results advance our understanding of the molecular mechanisms that specify a rare retinal cell type and show how disrupting this specification leads to a corresponding defect in neural circuitry and behavior.
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Affiliation(s)
- Timour Al-Khindi
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael B Sherman
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Takashi Kodama
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Otolaryngology & Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Preethi Gopal
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhiwei Pan
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - James K Kiraly
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hao Zhang
- Department of Microbiology and Immunology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Loyal A Goff
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sascha du Lac
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Otolaryngology & Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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6
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Yamasaki S, Kuwahara A, Kishino A, Kimura T, Takahashi M, Mandai M. Addition of Chk1 inhibitor and BMP4 cooperatively promotes retinal tissue formation in self-organizing human pluripotent stem cell differentiation culture. Regen Ther 2022; 19:24-34. [PMID: 35059477 PMCID: PMC8733178 DOI: 10.1016/j.reth.2021.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/09/2021] [Accepted: 12/16/2021] [Indexed: 11/20/2022] Open
Abstract
Background The BMP signaling pathway plays a key role in growth, differentiation and patterning during neural development. Recent work on the generation of a self-organization of three-dimensional retinal organoid (3D-retina) from human pluripotent stem cells (hPSCs) revealed that addition of recombinant human BMP4 (rhBMP4) promotes retinal differentiation in the early neural differentiation stage. For clinical application, efficient differentiation from hPSCs to retinal cells with minimal numbers of off-target non-retinal cells is desirable. We therefore aimed to further improve an efficient retinal differentiation method for future up-scaling of cell production. Methods hPSCs were differentiated into 3D-retina using a modified SFEBq method. The effect of rhBMP4 with or without Checkpoint kinase 1 (Chk1) inhibitor (PD407824), a modulator of BMP signaling pathway, at day 3 was compared by characterizing the differentiating 3D-retina by the use of the hPSCs and immunohistochemical analysis. Results The Chk1 inhibitor treatment promoted retinal differentiation from hPSCs, in combination with low-concentration rhBMP4. Addition of a Chk1 inhibitor generated a unique type of organoid with neural retina (NR) encapsulated in retinal pigment epithelium (RPE), possibly by promoting phosphorylation of SMAD1/5/9 in the cells inside the early aggregates. We confirmed that the Chk1-inhibitor-treated hPSC-3D-retina differentiated into rod and cone photoreceptor precursors and other types of retinal neurons, in long-term culture. Conclusions In this study, we found that combined use of rhBMP4 and a Chk1 inhibitor cooperatively promoted retinal differentiation from hPSCs. Our new retinal differentiation method is a promising option for the stable supply and up-scaling of production of 3D-retina for future cell therapy. Chk1 inhibitor cooperates with low-concentration rhBMP4 to promote hPSC-retinal differentiation. Combined rhBMP4 and Chk1 inhibitor treatment generated NR-RPE organoids with NR tissue encapsulated in RPE. In long-term culture, the Chk1 inhibitor-treated 3D-retina produces rod and cone photoreceptor precursors and other types of retinal neurons.
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7
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Multiple roles for Pax2 in the embryonic mouse eye. Dev Biol 2021; 472:18-29. [PMID: 33428890 DOI: 10.1016/j.ydbio.2020.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 02/07/2023]
Abstract
The vertebrate eye anlage grows out of the brain and folds into bilayered optic cups. The eye is patterned along multiple axes, precisely controlled by genetic programs, to delineate neural retina, pigment epithelium, and optic stalk tissues. Pax genes encode developmental regulators of key morphogenetic events, with Pax2 being essential for interpreting inductive signals, including in the eye. PAX2 mutations cause ocular coloboma, when the ventral optic fissure fails to close. Previous studies established that Pax2 is necessary for fissure closure and to maintain the neural retina -- glial optic stalk boundary. Using a Pax2GFP/+ knock-in allele we discovered that the mutant optic nerve head (ONH) lacks molecular boundaries with the retina and RPE, rendering the ONH larger than normal. This was preceded by ventronasal cup mispatterning, a burst of overproliferation and followed by optic cup apoptosis. Our findings support the hypothesis that ONH cells are tripotential, requiring Pax2 to remain committed to glial fates. This work extends current models of ocular development, contributes to broader understanding of tissue boundary formation and informs the underlying mechanisms of human coloboma.
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8
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Exploring the Expression of Cardiac Regulators in a Vertebrate Extremophile: The Cichlid Fish Oreochromis (Alcolapia) alcalica. J Dev Biol 2020; 8:jdb8040022. [PMID: 33020460 PMCID: PMC7712675 DOI: 10.3390/jdb8040022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/25/2020] [Accepted: 09/30/2020] [Indexed: 01/05/2023] Open
Abstract
Although it is widely accepted that the cellular and molecular mechanisms of vertebrate cardiac development are evolutionarily conserved, this is on the basis of data from only a few model organisms suited to laboratory studies. Here, we investigate gene expression during cardiac development in the extremophile, non-model fish species, Oreochromis (Alcolapia) alcalica. We first characterise the early development of O. alcalica and observe extensive vascularisation across the yolk prior to hatching. We further investigate heart development by identifying and cloning O. alcalica orthologues of conserved cardiac transcription factors gata4, tbx5, and mef2c for analysis by in situ hybridisation. Expression of these three key cardiac developmental regulators also reveals other aspects of O. alcalica development, as these genes are expressed in developing blood, limb, eyes, and muscle, as well as the heart. Our data support the notion that O. alcalica is a direct-developing vertebrate that shares the highly conserved molecular regulation of the vertebrate body plan. However, the expression of gata4 in O. alcalica reveals interesting differences in the development of the circulatory system distinct from that of the well-studied zebrafish. Understanding the development of O. alcalica embryos is an important step towards providing a model for future research into the adaptation to extreme conditions; this is particularly relevant given that anthropogenic-driven climate change will likely result in more freshwater organisms being exposed to less favourable conditions.
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9
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Yoon KH, Fox SC, Dicipulo R, Lehmann OJ, Waskiewicz AJ. Ocular coloboma: Genetic variants reveal a dynamic model of eye development. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:590-610. [PMID: 32852110 DOI: 10.1002/ajmg.c.31831] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/21/2022]
Abstract
Ocular coloboma is a congenital disorder of the eye where a gap exists in the inferior retina, lens, iris, or optic nerve tissue. With a prevalence of 2-19 per 100,000 live births, coloboma, and microphthalmia, an associated ocular disorder, represent up to 10% of childhood blindness. It manifests due to the failure of choroid fissure closure during eye development, and it is a part of a spectrum of ocular disorders that include microphthalmia and anophthalmia. Use of genetic approaches from classical pedigree analyses to next generation sequencing has identified more than 40 loci that are associated with the causality of ocular coloboma. As we have expanded studies to include singleton cases, hereditability has been very challenging to prove. As such, researchers over the past 20 years, have unraveled the complex interrelationship amongst these 40 genes using vertebrate model organisms. Such research has greatly increased our understanding of eye development. These genes function to regulate initial specification of the eye field, migration of retinal precursors, patterning of the retina, neural crest cell biology, and activity of head mesoderm. This review will discuss the discovery of loci using patient data, their investigations in animal models, and the recent advances stemming from animal models that shed new light in patient diagnosis.
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Affiliation(s)
- Kevin H Yoon
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Sabrina C Fox
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Renée Dicipulo
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Ordan J Lehmann
- Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew J Waskiewicz
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
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10
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Cardozo MJ, Almuedo-Castillo M, Bovolenta P. Patterning the Vertebrate Retina with Morphogenetic Signaling Pathways. Neuroscientist 2019; 26:185-196. [PMID: 31509088 DOI: 10.1177/1073858419874016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The primordium of the vertebrate eye is composed of a pseudostratified and apparently homogeneous neuroepithelium, which folds inward to generate a bilayered optic cup. During these early morphogenetic events, the optic vesicle is patterned along three different axes-proximo-distal, dorso-ventral, and naso-temporal-and three major domains: the neural retina, the retinal pigment epithelium (RPE), and the optic stalk. These fundamental steps that enable the subsequent development of a functional eye, entail the precise coordination among genetic programs. These programs are driven by the interplay of signaling pathways and transcription factors, which progressively dictate how each tissue should evolve. Here, we discuss the contribution of the Hh, Wnt, FGF, and BMP signaling pathways to the early patterning of the retina. Comparative studies in different vertebrate species have shown that their morphogenetic activity is repetitively used to orchestrate the progressive specification of the eye with evolutionary conserved mechanisms that have been adapted to match the specific need of a given species.
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Affiliation(s)
- Marcos J Cardozo
- Centro de Biología Molecular "Severo Ochoa," (CSIC/UAM), Madrid, Spain.,CIBERER, ISCIII, Madrid, Spain
| | | | - Paola Bovolenta
- Centro de Biología Molecular "Severo Ochoa," (CSIC/UAM), Madrid, Spain.,CIBERER, ISCIII, Madrid, Spain
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11
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Wiegering A, Petzsch P, Köhrer K, Rüther U, Gerhardt C. GLI3 repressor but not GLI3 activator is essential for mouse eye patterning and morphogenesis. Dev Biol 2019; 450:141-154. [PMID: 30953627 DOI: 10.1016/j.ydbio.2019.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 12/11/2022]
Abstract
Since 1967, it is known that the loss of GLI3 causes very severe defects in murine eye development. GLI3 is able to act as a transcriptional activator (GLI3-A) or as a transcriptional repressor (GLI3-R). Soon after the discovery of these GLI3 isoforms, the question arose which of the different isoforms is involved in eye formation - GLI3-A, GLI3-R or even both. For several years, this question remained elusive. By analysing the eye morphogenesis of Gli3XtJ/XtJ mouse embryos that lack GLI3-A and GLI3-R and of Gli3Δ699/Δ699 mouse embryos in which only GLI3-A is missing, we revealed that GLI3-A is dispensable in vertebrate eye formation. Remarkably, our study shows that GLI3-R is sufficient for the creation of morphologically normal eyes although the molecular setup deviates substantially from normality. In depth-investigations elucidated that GLI3-R controls numerous key players in eye development and governs lens and retina development at least partially via regulating WNT/β-CATENIN signalling.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Patrick Petzsch
- Biological and Medical Research Center (BMFZ), Genomics and Transcriptomics Laboratory (GTL), Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Karl Köhrer
- Biological and Medical Research Center (BMFZ), Genomics and Transcriptomics Laboratory (GTL), Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Ulrich Rüther
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
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12
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Knickmeyer MD, Mateo JL, Eckert P, Roussa E, Rahhal B, Zuniga A, Krieglstein K, Wittbrodt J, Heermann S. TGFβ-facilitated optic fissure fusion and the role of bone morphogenetic protein antagonism. Open Biol 2019; 8:rsob.170134. [PMID: 29593116 PMCID: PMC5881030 DOI: 10.1098/rsob.170134] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 03/02/2018] [Indexed: 12/25/2022] Open
Abstract
The optic fissure is a transient gap in the developing vertebrate eye, which must be closed as development proceeds. A persisting optic fissure, coloboma, is a major cause for blindness in children. Although many genes have been linked to coloboma, the process of optic fissure fusion is still little appreciated, especially on a molecular level. We identified a coloboma in mice with a targeted inactivation of transforming growth factor β2 (TGFβ2). Notably, here the optic fissure margins must have touched, however failed to fuse. Transcriptomic analyses indicated an effect on remodelling of the extracellular matrix (ECM) as an underlying mechanism. TGFβ signalling is well known for its effect on ECM remodelling, but it is at the same time often inhibited by bone morphogenetic protein (BMP) signalling. Notably, we also identified two BMP antagonists among the downregulated genes. For further functional analyses we made use of zebrafish, in which we found TGFβ ligands expressed in the developing eye, and the ligand binding receptor in the optic fissure margins where we also found active TGFβ signalling and, notably, also gremlin 2b (grem2b) and follistatin a (fsta), homologues of the regulated BMP antagonists. We hypothesized that TGFβ is locally inducing expression of BMP antagonists within the margins to relieve the inhibition from its regulatory capacity regarding ECM remodelling. We tested our hypothesis and found that induced BMP expression is sufficient to inhibit optic fissure fusion, resulting in coloboma. Our findings can likely be applied also to other fusion processes, especially when TGFβ signalling or BMP antagonism is involved, as in fusion processes during orofacial development.
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Affiliation(s)
- Max D Knickmeyer
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg D-79104, Germany.,Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, Freiburg D-79104, Germany
| | - Juan L Mateo
- Departamento de Informática, Universidad de Oviedo, Jesús Arias de Velasco, Oviedo 33005, Spain
| | - Priska Eckert
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg D-79104, Germany.,Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, Freiburg D-79104, Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg D-79104, Germany
| | - Belal Rahhal
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg D-79104, Germany
| | - Aimee Zuniga
- Developmental Genetics, University of Basel Medical School, Basel CH-4058, Switzerland
| | - Kerstin Krieglstein
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg D-79104, Germany
| | | | - Stephan Heermann
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg D-79104, Germany
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13
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Shirahama M, Steinfeld I, Karaiwa A, Taketani S, Vogel-Höpker A, Layer PG, Araki M. Change in the developmental fate of the chick optic vesicle from the neural retina to the telencephalon. Dev Growth Differ 2019; 61:252-262. [PMID: 30843193 DOI: 10.1111/dgd.12599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 11/27/2022]
Abstract
The forebrain develops into the telencephalon, diencephalon, and optic vesicle (OV). The OV further develops into the optic cup, the inner and outer layers of which develop into the neural retina and retinal pigmented epithelium (RPE), respectively. We studied the change in fate of the OV by using embryonic transplantation and explant culture methods. OVs excised from 10-somite stage chick embryos were freed from surrounding tissues (the surface ectoderm and mesenchyme) and were transplanted back to their original position in host embryos. Expression of neural retina-specific genes, such as Rax and Vsx2 (Chx10), was downregulated in the transplants. Instead, expression of the telencephalon-specific gene Emx1 emerged in the proximal region of the transplants, and in the distal part of the transplants close to the epidermis, expression of an RPE-specific gene Mitf was observed. Explant culture studies showed that when OVs were cultured alone, Rax was continuously expressed regardless of surrounding tissues (mesenchyme and epidermis). When OVs without surrounding tissues were cultured in close contact with the anterior forebrain, Rax expression became downregulated in the explants, and Emx1 expression became upregulated. These findings indicate that chick OVs at stage 10 are bi-potential with respect to their developmental fates, either for the neural retina or for the telencephalon, and that the surrounding tissues have a pivotal role in their actual fates. An in vitro tissue culture model suggests that under the influence of the anterior forebrain and/or its surrounding tissues, the OV changes its fate from the retina to the telencephalon.
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Affiliation(s)
- Misaki Shirahama
- Developmental Neurobiology Laboratory, Nara Women's University, Nara, Japan
| | - Ichie Steinfeld
- Developmental Neurobiology Laboratory, Nara Women's University, Nara, Japan.,Entwicklungsbiologie & Neurogenetik, Technische Universität Darmstadt, Darmstadt, Germany
| | - Akari Karaiwa
- Developmental Neurobiology Laboratory, Nara Women's University, Nara, Japan
| | - Shigeru Taketani
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto, Japan
| | - Astrid Vogel-Höpker
- Entwicklungsbiologie & Neurogenetik, Technische Universität Darmstadt, Darmstadt, Germany
| | - Paul G Layer
- Entwicklungsbiologie & Neurogenetik, Technische Universität Darmstadt, Darmstadt, Germany
| | - Masasuke Araki
- Developmental Neurobiology Laboratory, Nara Women's University, Nara, Japan.,Unit of Neural Development and Regeneration, Nara Medical University, Kashihara, Japan
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14
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Grajales-Esquivel E, Luz-Madrigal A, Bierly J, Haynes T, Reis ES, Han Z, Gutierrez C, McKinney Z, Tzekou A, Lambris JD, Tsonis PA, Del Rio-Tsonis K. Complement component C3aR constitutes a novel regulator for chick eye morphogenesis. Dev Biol 2017; 428:88-100. [PMID: 28576690 PMCID: PMC5726978 DOI: 10.1016/j.ydbio.2017.05.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/05/2016] [Accepted: 05/17/2017] [Indexed: 12/22/2022]
Abstract
Complement components have been implicated in a wide variety of functions including neurogenesis, proliferation, cell migration, differentiation, cancer, and more recently early development and regeneration. Following our initial observations indicating that C3a/C3aR signaling induces chick retina regeneration, we analyzed its role in chick eye morphogenesis. During eye development, the optic vesicle (OV) invaginates to generate a bilayer optic cup (OC) that gives rise to the retinal pigmented epithelium (RPE) and neural retina. We show by immunofluorescence staining that C3 and the receptor for C3a (the cleaved and active form of C3), C3aR, are present in chick embryos during eye morphogenesis in the OV and OC. Interestingly, C3aR is mainly localized in the nuclear compartment at the OC stage. Loss of function studies at the OV stage using morpholinos or a blocking antibody targeting the C3aR (anti-C3aR Ab), causes eye defects such as microphthalmia and defects in the ventral portion of the eye that result in coloboma. Such defects were not observed when C3aR was disrupted at the OC stage. Histological analysis demonstrated that microphthalmic eyes were unable to generate a normal optic stalk or a closed OC. The dorsal/ventral patterning defects were accompanied by an expansion of the ventral markers Pax2, cVax and retinoic acid synthesizing enzyme raldh-3 (aldh1a3) domains, an absence of the dorsal expression of Tbx5 and raldh-1 (aldh1a1) and a re-specification of the ventral RPE to neuroepithelium. In addition, the eyes showed overall decreased expression of Gli1 and a change in distribution of nuclear β-catenin, suggesting that Shh and Wnt pathways have been affected. Finally, we observed prominent cell death along with a decrease in proliferating cells, indicating that both processes contribute to the microphthalmic phenotype. Together our results show that C3aR is necessary for the proper morphogenesis of the OC. This is the first report implicating C3aR in eye development, revealing an unsuspected hitherto regulator for proper chick eye morphogenesis.
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Affiliation(s)
- Erika Grajales-Esquivel
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA.
| | - Agustin Luz-Madrigal
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA; Department of Biology, University of Dayton and Center for Tissue Regeneration and Engineering at the University of Dayton (TREND), Dayton, OH 45469, USA.
| | - Jeffrey Bierly
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA.
| | - Tracy Haynes
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA.
| | - Edimara S Reis
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Zeyu Han
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA.
| | - Christian Gutierrez
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA.
| | - Zachary McKinney
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA.
| | - Apostolia Tzekou
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Panagiotis A Tsonis
- Department of Biology, University of Dayton and Center for Tissue Regeneration and Engineering at the University of Dayton (TREND), Dayton, OH 45469, USA.
| | - Katia Del Rio-Tsonis
- Department of Biology, Miami University and Center for Visual Sciences at Miami University (CVSMU), Oxford, OH 45056, USA.
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15
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Gama Marques J, Faro Viana P, Peralta AR. A "Sleeping Beauty" With a "Heart-Hand": Kleine-Levin Syndrome Treated With Buproprion and Carbamazepine in a Patient With Holt-Oram Syndrome. Clin EEG Neurosci 2017; 48:270-271. [PMID: 27090505 DOI: 10.1177/1550059416644087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- João Gama Marques
- 1 Clínica de Psicoses Esquizofrénicas, Hospital Júlio de Matos, Centro Hospitalar Psiquiátrico de Lisboa, Lisbon, Portugal.,2 Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Pedro Faro Viana
- 3 Serviço de Neurologia, Hospital Santa Maria, Centro Hospitalar Lisboa Norte, Lisbon, Portugal
| | - Ana Rita Peralta
- 2 Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,3 Serviço de Neurologia, Hospital Santa Maria, Centro Hospitalar Lisboa Norte, Lisbon, Portugal
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16
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Park E, Noh H, Park S. Identification of an Enhancer Critical for the ephirn-A5 Gene Expression in the Posterior Region of the Mesencephalon. Mol Cells 2017; 40:426-433. [PMID: 28614915 PMCID: PMC5523019 DOI: 10.14348/molcells.2017.0052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/01/2017] [Accepted: 05/11/2017] [Indexed: 11/27/2022] Open
Abstract
Ephrin-A5 has been implicated in the regulation of brain morphogenesis and axon pathfinding. In this study, we used bacterial homologous recombination to express a LacZ reporter in various ephrin-A5 BAC clones to identify elements that regulate ephrin-A5 gene expression during mesencephalon development. We found that there is mesencephalon-specific enhancer activity localized to a specific +25.0 kb to +30.5 kb genomic region in the first intron of ephrin-A5. Further comparative genomic analysis indicated that two evolutionary conserved regions, ECR1 and ECR2, were present within this 5.5 kb region. Deletion of ECR1 from the enhancer resulted in disrupted mesencephalon-specific enhancer activity in transgenic embryos. We also found a consensus binding site for basic helix-loop-helix (bHLH) transcription factors (TFs) in a highly conserved region at the 3'-end of ECR1. We further demonstrated that specific deletion of the bHLH TF binding site abrogated the mesencephalon-specific enhancer activity in transgenic embryos. Finally, both electrophoretic mobility shift assay and luciferase-based transactivation assay revealed that the transcription factor Ascl1 bound the bHLH consensus binding site in the mesencephalon-specific ephrin-A5 enhancer in vitro. Together, these results suggest that the bHLH TF binding site in ECR1 is involved in the positive regulation of ephrin-A5 gene expression during the development of the mesencephalon.
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Affiliation(s)
- Eunjeong Park
- Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310,
Korea
| | - Hyuna Noh
- Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310,
Korea
| | - Soochul Park
- Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310,
Korea
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17
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Hasegawa Y, Takata N, Okuda S, Kawada M, Eiraku M, Sasai Y. Emergence of dorsal-ventral polarity in ESC-derived retinal tissue. Development 2016; 143:3895-3906. [PMID: 27633992 DOI: 10.1242/dev.134601] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 09/01/2016] [Indexed: 01/08/2023]
Abstract
We previously demonstrated that mouse embryonic stem cell (mESC)-derived retinal epithelium self-forms an optic cup-like structure. In the developing retina, the dorsal and ventral sides differ in terms of local gene expression and morphological features. This aspect has not yet been shown in vitro Here, we demonstrate that mESC-derived retinal tissue spontaneously acquires polarity reminiscent of the dorsal-ventral (D-V) patterning of the embryonic retina. Tbx5 and Vax2 were expressed in a mutually exclusive manner, as seen in vivo Three-dimensional morphometric analysis showed that the in vitro-formed optic cup often contains cleft structures resembling the embryonic optic fissure. To elucidate the mechanisms underlying the spontaneous D-V polarization of mESC-derived retina, we examined the effects of patterning factors, and found that endogenous BMP signaling plays a predominant role in the dorsal specification. Further analysis revealed that canonical Wnt signaling, which was spontaneously activated at the proximal region, acts upstream of BMP signaling for dorsal specification. These observations suggest that D-V polarity could be established within the self-formed retinal neuroepithelium by intrinsic mechanisms involving the spatiotemporal regulation of canonical Wnt and BMP signals.
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Affiliation(s)
- Yuiko Hasegawa
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan.,Laboratory for in vitro Histogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan
| | - Nozomu Takata
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan.,Laboratory for in vitro Histogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan
| | - Satoru Okuda
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan.,Laboratory for in vitro Histogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan
| | - Masako Kawada
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan.,Laboratory for in vitro Histogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan
| | - Mototsugu Eiraku
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan .,Laboratory for in vitro Histogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan
| | - Yoshiki Sasai
- Laboratory for Organogenesis and Neurogenesis, RIKEN Center for Developmental Biology, 2-2-3, Minatojima-Minamimachi, Chuo, Kobe 650-0047, Japan
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18
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Heermann S, Schütz L, Lemke S, Krieglstein K, Wittbrodt J. Eye morphogenesis driven by epithelial flow into the optic cup facilitated by modulation of bone morphogenetic protein. eLife 2015; 4. [PMID: 25719386 PMCID: PMC4337729 DOI: 10.7554/elife.05216] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/26/2015] [Indexed: 01/07/2023] Open
Abstract
The hemispheric, bi-layered optic cup forms from an oval optic vesicle during early vertebrate eye development through major morphological transformations. The overall basal surface, facing the developing lens, is increasing, while, at the same time, the space basally occupied by individual cells is decreasing. This cannot be explained by the classical view of eye development. Using zebrafish (Danio rerio) as a model, we show that the lens-averted epithelium functions as a reservoir that contributes to the growing neuroretina through epithelial flow around the distal rims of the optic cup. We propose that this flow couples morphogenesis and retinal determination. Our 4D data indicate that future stem cells flow from their origin in the lens-averted domain of the optic vesicle to their destination in the ciliary marginal zone. BMP-mediated inhibition of the flow results in ectopic neuroretina in the RPE domain. Ultimately the ventral fissure fails to close resulting in coloboma. DOI:http://dx.doi.org/10.7554/eLife.05216.001 The eye is our most important organ for sensing and recognizing our environment. In humans and other vertebrates, the eye forms from an outgrowth of the brain as the embryo develops. This outgrowth is called the optic vesicle and it is rapidly transformed into a cup-shaped structure known as the optic cup. Defects in this process prevent the optic cup from closing completely, which leads to a severe condition called Coloboma—one of the most frequent causes of blindness in children. The optic cup has two distinct layers: the inside layer—known as the neuroretina—contains light sensitive cells and is surrounded by the other layer called the pigmented epithelium. It is thought that the neural retina is made from cells from the side of the optic vesicle that faces the lens, and the pigmented epithelium is formed by cells from the other side of the vesicle. This is a plausible explanation and is well accepted, but it cannot explain how the neuroretina can become five times larger as the cup forms. Heermann et al. addressed this problem by using four-dimensional in vivo microscopy to follow individual cells as the optic cup forms in living zebrafish embryos. The experiments show that the neuroretina is made of cells from both sides of the optic vesicle. Cells from the back of the optic vesicle (furthest away from the lens) join the rest of the cells by moving around the outside rim of the cup. Further experiments found that a signaling molecule called BMP—which is crucial to the normal development of the eye—controls the flow of cells around the developing optic cup. This factor needs to be carefully controlled during the development of the eye; when BMP activity was artificially increased, the flow of cells stopped, resulting in neuroretinal tissue developing in the wrong place (in the outer layer of the optic cup). The experiments also reveal that the stem cells in the retina—which divide to produce new cells throughout the life of the zebrafish—originate from two distinct areas in the optic vesicle. Heermann et al.'s findings challenge the textbook model of eye development by revealing that cells from both sides of the optic vesicle contribute to the neuroretina and that retinal stem cells originate from a specific place in the developing eye. A future challenge will be to understand how the movement of the cells into the neuroretina is coordinated to make a perfectly shaped eye. DOI:http://dx.doi.org/10.7554/eLife.05216.002
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Affiliation(s)
- Stephan Heermann
- Centre for Organismal Studies Heidelberg, Ruprecht Karls Universität, Heidelberg, Germany
| | - Lucas Schütz
- Centre for Organismal Studies Heidelberg, Ruprecht Karls Universität, Heidelberg, Germany
| | - Steffen Lemke
- Centre for Organismal Studies Heidelberg, Ruprecht Karls Universität, Heidelberg, Germany
| | - Kerstin Krieglstein
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, University Freiburg, Freiburg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies Heidelberg, Ruprecht Karls Universität, Heidelberg, Germany
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19
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Abstract
The visual system is beautifully crafted to transmit information of the external world to visual processing and cognitive centers in the brain. For visual information to be relayed to the brain, a series of axon pathfinding events must take place to ensure that the axons of retinal ganglion cells, the only neuronal cell type in the retina that sends axons out of the retina, find their way out of the eye to connect with targets in the brain. In the past few decades, the power of molecular and genetic tools, including the generation of genetically manipulated mouse lines, have multiplied our knowledge about the molecular mechanisms involved in the sculpting of the visual system. Here, we review major advances in our understanding of the mechanisms controlling the differentiation of RGCs, guidance of their axons from the retina to the primary visual centers, and the refinement processes essential for the establishment of topographic maps and eye-specific axon segregation. Human disorders, such as albinism and achiasmia, that impair RGC axon growth and guidance and, thus, the establishment of a fully functioning visual system will also be discussed.
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Affiliation(s)
- Lynda Erskine
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Scotland, UK
| | - Eloisa Herrera
- Instituto de Neurosciencias de Alicante, CSIC-UMH, San Juan de Alicante, Spain
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20
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Zagozewski JL, Zhang Q, Eisenstat DD. Genetic regulation of vertebrate eye development. Clin Genet 2014; 86:453-60. [PMID: 25174583 DOI: 10.1111/cge.12493] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 08/04/2014] [Accepted: 08/20/2014] [Indexed: 01/14/2023]
Abstract
Eye development is a complex and highly regulated process that consists of several overlapping stages: (i) specification then splitting of the eye field from the developing forebrain; (ii) genesis and patterning of the optic vesicle; (iii) regionalization of the optic cup into neural retina and retina pigment epithelium; and (iv) specification and differentiation of all seven retinal cell types that develop from a pool of retinal progenitor cells in a precise temporal and spatial manner: retinal ganglion cells, horizontal cells, cone photoreceptors, amacrine cells, bipolar cells, rod photoreceptors and Müller glia. Genetic regulation of the stages of eye development includes both extrinsic (such as morphogens, growth factors) and intrinsic factors (primarily transcription factors of the homeobox and basic helix-loop helix families). In the following review, we will provide an overview of the stages of eye development highlighting the role of several important transcription factors in both normal developmental processes and in inherited human eye diseases.
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Affiliation(s)
- J L Zagozewski
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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21
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Ebert AM, Childs SJ, Hehr CL, Cechmanek PB, McFarlane S. Sema6a and Plxna2 mediate spatially regulated repulsion within the developing eye to promote eye vesicle cohesion. Development 2014; 141:2473-82. [PMID: 24917502 DOI: 10.1242/dev.103499] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Organs are generated from collections of cells that coalesce and remain together as they undergo a series of choreographed movements to give the organ its final shape. We know little about the cellular and molecular mechanisms that regulate tissue cohesion during morphogenesis. Extensive cell movements underlie eye development, starting with the eye field separating to form bilateral vesicles that go on to evaginate from the forebrain. What keeps eye cells together as they undergo morphogenesis and extensive proliferation is unknown. Here, we show that plexina2 (Plxna2), a member of a receptor family best known for its roles in axon and cell guidance, is required alongside the repellent semaphorin 6a (Sema6a) to keep cells integrated within the zebrafish eye vesicle epithelium. sema6a is expressed throughout the eye vesicle, whereas plxna2 is restricted to the ventral vesicle. Knockdown of Plxna2 or Sema6a results in a loss of vesicle integrity, with time-lapse microscopy showing that eye progenitors either fail to enter the evaginating vesicles or delaminate from the eye epithelium. Explant experiments, and rescue of eye vesicle integrity with simultaneous knockdown of sema6a and plxna2, point to an eye-autonomous requirement for Sema6a/Plxna2. We propose a novel, tissue-autonomous mechanism of organ cohesion, with neutralization of repulsion suggested as a means to promote interactions between cells within a tissue domain.
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Affiliation(s)
- Alicia M Ebert
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Calgary, Alberta T2N 4N1, Canada
| | - Sarah J Childs
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Carrie L Hehr
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Calgary, Alberta T2N 4N1, Canada
| | - Paula B Cechmanek
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Calgary, Alberta T2N 4N1, Canada
| | - Sarah McFarlane
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Calgary, Alberta T2N 4N1, Canada
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22
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Hoon M, Okawa H, Della Santina L, Wong ROL. Functional architecture of the retina: development and disease. Prog Retin Eye Res 2014; 42:44-84. [PMID: 24984227 DOI: 10.1016/j.preteyeres.2014.06.003] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/08/2014] [Accepted: 06/22/2014] [Indexed: 12/22/2022]
Abstract
Structure and function are highly correlated in the vertebrate retina, a sensory tissue that is organized into cell layers with microcircuits working in parallel and together to encode visual information. All vertebrate retinas share a fundamental plan, comprising five major neuronal cell classes with cell body distributions and connectivity arranged in stereotypic patterns. Conserved features in retinal design have enabled detailed analysis and comparisons of structure, connectivity and function across species. Each species, however, can adopt structural and/or functional retinal specializations, implementing variations to the basic design in order to satisfy unique requirements in visual function. Recent advances in molecular tools, imaging and electrophysiological approaches have greatly facilitated identification of the cellular and molecular mechanisms that establish the fundamental organization of the retina and the specializations of its microcircuits during development. Here, we review advances in our understanding of how these mechanisms act to shape structure and function at the single cell level, to coordinate the assembly of cell populations, and to define their specific circuitry. We also highlight how structure is rearranged and function is disrupted in disease, and discuss current approaches to re-establish the intricate functional architecture of the retina.
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Affiliation(s)
- Mrinalini Hoon
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Haruhisa Okawa
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Luca Della Santina
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA.
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Tang K, Tsai SY, Tsai MJ. COUP-TFs and eye development. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:201-9. [PMID: 24878540 DOI: 10.1016/j.bbagrm.2014.05.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 12/13/2022]
Abstract
Recent studies reveal that COUP-TF genes are essential for neural development, cardiovascular development, energy metabolism and adipogenesis, as well as for organogenesis of multiple systems. In this review, we mainly describe the COUP-TF genes, molecular mechanisms of COUP-TF action, and their crucial functions in the morphogenesis of the murine eye. Mutations of COUP-TF genes lead to the congenital coloboma and/or optic atrophy in both mouse and human, indicating that the study on COUP-TFs and the eye will benefit our understanding of the etiology of human ocular diseases. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
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Affiliation(s)
- Ke Tang
- Institute of Life Science, Nanchang University, Nanchang, Jiangxi 330031, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Sophia Y Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Ming-Jer Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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24
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Pi-Roig A, Martin-Blanco E, Minguillon C. Distinct tissue-specific requirements for the zebrafish tbx5 genes during heart, retina and pectoral fin development. Open Biol 2014; 4:140014. [PMID: 24759614 PMCID: PMC4043114 DOI: 10.1098/rsob.140014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The transcription factor Tbx5 is expressed in the developing heart, eyes and anterior appendages. Mutations in human TBX5 cause Holt-Oram syndrome, a condition characterized by heart and upper limb malformations. Tbx5-knockout mouse embryos have severely impaired forelimb and heart morphogenesis from the earliest stages of their development. However, zebrafish embryos with compromised tbx5 function show a complete absence of pectoral fins, while heart development is disturbed at significantly later developmental stages and eye development remains to be thoroughly analysed. We identified a novel tbx5 gene in zebrafish--tbx5b--that is co-expressed with its paralogue, tbx5a, in the developing eye and heart and hypothesized that functional redundancy could be occurring in these organs in embryos with impaired tbx5a function. We have now investigated the consequences of tbx5a and/or tbx5b downregulation in zebrafish to reveal that tbx5 genes have essential roles in the establishment of cardiac laterality, dorsoventral retina axis organization and pectoral fin development. Our data show that distinct relationships between tbx5 paralogues are required in a tissue-specific manner to ensure the proper morphogenesis of the three organs in which they are expressed. Furthermore, we uncover a novel role for tbx5 genes in the establishment of correct heart asymmetry in zebrafish embryos.
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Affiliation(s)
- Aina Pi-Roig
- CSIC-Institut de Biologia Molecular de Barcelona, Department of Developmental Biology, Parc Científic de Barcelona, C/Baldiri Reixac, 10, Barcelona 08028, Spain
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25
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Abstract
We previously identified SPARC-related protein-containing immunoglobulin domains 1 (SPIG1, also known as Follistatin-like protein 4) as one of the dorsal-retina-specific molecules expressed in the developing chick retina. We here demonstrated that the knockdown of SPIG1 in the retinal ganglion cells (RGCs) of developing chick embryos induced the robust ectopic branching of dorsal RGC axons and failed to form a tight terminal zone at the proper position on the tectum. The knockdown of SPIG1 in RGCs also led to enhanced axon branching in vitro. However, this was canceled by the addition of a neutralizing antibody against brain-derived neurotrophic factor (BDNF) to the culture medium. SPIG1 and BDNF were colocalized in vesicle-like structures in cells. SPIG1 bound with the proform of BDNF (proBDNF) but very weakly with mature BDNF in vitro. The expression and secretion of mature BDNF were significantly decreased when SPIG1 was exogenously expressed with BDNF in HEK293T or PC12 cells. The amount of mature BDNF proteins as well as the tyrosine phosphorylation level of the BDNF receptor, tropomyosin-related kinase B (TrkB), in the hippocampus were significantly higher in SPIG1-knockout mice than in wild-type mice. Here the spine density of CA1 pyramidal neurons was consistently increased. Together, these results suggest that SPIG1 negatively regulated BDNF maturation by binding to proBDNF, thereby suppressing axonal branching and spine formation.
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26
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Sfrp1a and Sfrp5 function as positive regulators of Wnt and BMP signaling during early retinal development. Dev Biol 2014; 388:192-204. [PMID: 24457098 DOI: 10.1016/j.ydbio.2014.01.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 12/16/2013] [Accepted: 01/13/2014] [Indexed: 01/08/2023]
Abstract
Axial patterning of the developing eye is critically important for proper axonal pathfinding as well as for key morphogenetic events, such as closure of the optic fissure. The dorsal retina is initially specified by the actions of Bone Morphogenetic Protein (BMP) signaling, with such identity subsequently maintained by the Wnt-β catenin pathway. Using zebrafish as a model system, we demonstrate that Secreted frizzled-related protein 1a (Sfrp1a) and Sfrp5 work cooperatively to pattern the retina along the dorso-ventral axis. Sfrp1a/5 depleted embryos display a reduction in dorsal marker gene expression that is consistent with defects in BMP- and Wnt-dependent dorsal retina identity. In accord with this finding, we observe a marked reduction in transgenic reporters of BMP and Wnt signaling within the dorsal retina of Sfrp1a/5 depleted embryos. In contrast to studies in which canonical Wnt signaling is blocked, we note an increase in BMP ligand expression in Sfrp1a/5 depleted embryos, a phenotype similar to that seen in embryos with inhibited BMP signaling. Overexpression of a low dose of sfrp5 mRNA causes an increase in dorsal retina marker gene expression. We propose a model in which Sfrp proteins function as facilitators of both BMP and Wnt signaling within the dorsal retina.
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27
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Hägglund AC, Berghard A, Carlsson L. Canonical Wnt/β-catenin signalling is essential for optic cup formation. PLoS One 2013; 8:e81158. [PMID: 24324671 PMCID: PMC3852023 DOI: 10.1371/journal.pone.0081158] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 10/09/2013] [Indexed: 12/17/2022] Open
Abstract
A multitude of signalling pathways are involved in the process of forming an eye. Here we demonstrate that β-catenin is essential for eye development as inactivation of β-catenin prior to cellular specification in the optic vesicle caused anophthalmia in mice. By achieving this early and tissue-specific β-catenin inactivation we find that retinal pigment epithelium (RPE) commitment was blocked and eye development was arrested prior to optic cup formation due to a loss of canonical Wnt signalling in the dorsal optic vesicle. Thus, these results show that Wnt/β-catenin signalling is required earlier and play a more central role in eye development than previous studies have indicated. In our genetic model system a few RPE cells could escape β-catenin inactivation leading to the formation of a small optic rudiment. The optic rudiment contained several neural retinal cell classes surrounded by an RPE. Unlike the RPE cells, the neural retinal cells could be β-catenin-negative revealing that differentiation of the neural retinal cell classes is β-catenin-independent. Moreover, although dorsoventral patterning is initiated in the mutant optic vesicle, the neural retinal cells in the optic rudiment displayed almost exclusively ventral identity. Thus, β-catenin is required for optic cup formation, commitment to RPE cells and maintenance of dorsal identity of the retina.
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Affiliation(s)
| | - Anna Berghard
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Leif Carlsson
- Umeå Center for Molecular Medicine, Umeå University, Umeå, Sweden
- * E-mail:
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28
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Schulte D, Frank D. TALE transcription factors during early development of the vertebrate brain and eye. Dev Dyn 2013; 243:99-116. [DOI: 10.1002/dvdy.24030] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/11/2013] [Accepted: 07/13/2013] [Indexed: 12/25/2022] Open
Affiliation(s)
- Dorothea Schulte
- Institute of Neurology (Edinger Institute); University Hospital Frankfurt, J.W. Goethe University; Frankfurt Germany
| | - Dale Frank
- Department of Biochemistry; The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology; Haifa Israel
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29
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Zhang R, Huang H, Cao P, Wang Z, Chen Y, Pan Y. Sma- and Mad-related protein 7 (Smad7) is required for embryonic eye development in the mouse. J Biol Chem 2013; 288:10275-85. [PMID: 23426374 PMCID: PMC3624411 DOI: 10.1074/jbc.m112.416719] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 02/19/2013] [Indexed: 01/16/2023] Open
Abstract
Smad7 is an intracellular inhibitory protein that antagonizes the signaling of TGF-β family members. Deletion of Smad7 in the mouse leads to an abnormality in heart development. However, whether Smad7 has a functional role in the development of other organs has been elusive. Here we present evidence that Smad7 imparts a role to eye development in the mouse. Smad7 is expressed in both the lens and retina in the developing embryonic eye. Depletion of Smad7 caused various degrees of coloboma and microphthalmia with alterations in cell apoptosis and proliferation in eyes. Smad7 was implicated in lens differentiation but was not required for the induction of the lens placode. The development of the periocular mesenchyme was retarded with the down-regulation of Bmp7 and Pitx2 in mutant mice. Retinal spatial patterning was affected by Smad7 deletion and was accompanied by altered bone morphogenetic protein (BMP) signaling. At late gestation stages, TGF-β signaling was up-regulated in the differentiating retina. Smad7 mutant mice displayed an expanded optic disc with increasing of sonic hedgehog (SHH) signaling. Furthermore, loss of Smad7 led to a temporal change in retinal neurogenesis. In conclusion, our study suggests that Smad7 is essential for eye development. In addition, our data indicate that alterations in the signaling of BMP, TGF-β, and SHH likely underlie the defects in eye development caused by Smad7 deletion.
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Affiliation(s)
- Rui Zhang
- From the Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China
| | - Heng Huang
- From the Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China
| | - Peijuan Cao
- From the Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhenzhen Wang
- From the Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China
| | - Yan Chen
- From the Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China
| | - Yi Pan
- From the Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China
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30
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Asai-Coakwell M, March L, Dai XH, Duval M, Lopez I, French CR, Famulski J, De Baere E, Francis PJ, Sundaresan P, Sauvé Y, Koenekoop RK, Berry FB, Allison WT, Waskiewicz AJ, Lehmann OJ. Contribution of growth differentiation factor 6-dependent cell survival to early-onset retinal dystrophies. Hum Mol Genet 2013; 22:1432-42. [PMID: 23307924 DOI: 10.1093/hmg/dds560] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Retinal dystrophies are predominantly caused by mutations affecting the visual phototransduction system and cilia, with few genes identified that function to maintain photoreceptor survival. We reasoned that growth factors involved with early embryonic retinal development would represent excellent candidates for such diseases. Here we show that mutations in the transforming growth factor-β (TGF-β) ligand Growth Differentiation Factor 6, which specifies the dorso-ventral retinal axis, contribute to Leber congenital amaurosis. Furthermore, deficiency of gdf6 results in photoreceptor degeneration, so demonstrating a connection between Gdf6 signaling and photoreceptor survival. In addition, in both murine and zebrafish mutant models, we observe retinal apoptosis, a characteristic feature of human retinal dystrophies. Treatment of gdf6-deficient zebrafish embryos with a novel aminopropyl carbazole, P7C3, rescued the retinal apoptosis without evidence of toxicity. These findings implicate for the first time perturbed TGF-β signaling in the genesis of retinal dystrophies, support the study of related morphogenetic genes for comparable roles in retinal disease and may offer additional therapeutic opportunities for genetically heterogeneous disorders presently only treatable with gene therapy.
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Affiliation(s)
- Mika Asai-Coakwell
- Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
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31
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Chiavacci E, Dolfi L, Verduci L, Meghini F, Gestri G, Evangelista AMM, Wilson SW, Cremisi F, Pitto L. MicroRNA 218 mediates the effects of Tbx5a over-expression on zebrafish heart development. PLoS One 2012; 7:e50536. [PMID: 23226307 PMCID: PMC3511548 DOI: 10.1371/journal.pone.0050536] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 10/26/2012] [Indexed: 11/18/2022] Open
Abstract
tbx5, a member of the T-box gene family, encodes one of the key transcription factors mediating vertebrate heart development. Tbx5 function in heart development appears to be exquisitely sensitive to gene dosage, since both haploinsufficiency and gene duplication generate the cardiac abnormalities associated with Holt−Oram syndrome (HOS), a highly penetrant autosomal dominant disease characterized by congenital heart defects of varying severity and upper limb malformation. It is suggested that tight integration of microRNAs and transcription factors into the cardiac genetic circuitry provides a rich and robust array of regulatory interactions to control cardiac gene expression. Based on these considerations, we performed an in silico screening to identify microRNAs embedded in genes highly sensitive to Tbx5 dosage. Among the identified microRNAs, we focused our attention on miR-218-1 that, together with its host gene, slit2, is involved in heart development. We found correlated expression of tbx5 and miR-218 during cardiomyocyte differentiation of mouse P19CL6 cells. In zebrafish embryos, we show that both Tbx5 and miR-218 dysregulation have a severe impact on heart development, affecting early heart morphogenesis. Interestingly, down-regulation of miR-218 is able to rescue the heart defects generated by tbx5 over-expression supporting the notion that miR-218 is a crucial mediator of Tbx5 in heart development and suggesting its possible involvement in the onset of heart malformations.
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Affiliation(s)
| | - Luca Dolfi
- Institute of Clinical Physiology, CNR, Pisa, Italy
| | | | | | - Gaia Gestri
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | | | - Stephen W. Wilson
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | | | - Letizia Pitto
- Institute of Clinical Physiology, CNR, Pisa, Italy
- * E-mail:
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32
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Dearborn RE, Dai Y, Reed B, Karian T, Gray J, Kunes S. Reph, a regulator of Eph receptor expression in the Drosophila melanogaster optic lobe. PLoS One 2012; 7:e37303. [PMID: 22615969 PMCID: PMC3353934 DOI: 10.1371/journal.pone.0037303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 04/19/2012] [Indexed: 11/19/2022] Open
Abstract
Receptors of the Eph family of tyrosine kinases and their Ephrin ligands are involved in developmental processes as diverse as angiogenesis, axon guidance and cell migration. However, our understanding of the Eph signaling pathway is incomplete, and could benefit from an analysis by genetic methods. To this end, we performed a genetic modifier screen for mutations that affect Eph signaling in Drosophila melanogaster. Several dozen loci were identified on the basis of their suppression or enhancement of an eye defect induced by the ectopic expression of Ephrin during development; many of these mutant loci were found to disrupt visual system development. One modifier locus, reph (regulator of eph expression), was characterized in molecular detail and found to encode a putative nuclear protein that interacts genetically with Eph signaling pathway mutations. Reph is an autonomous regulator of Eph receptor expression, required for the graded expression of Eph protein and the establishment of an optic lobe axonal topographic map. These results reveal a novel component of the regulatory pathway controlling expression of eph and identify reph as a novel factor in the developing visual system.
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Affiliation(s)
- Richard E Dearborn
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, United States of America.
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33
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Shaham O, Menuchin Y, Farhy C, Ashery-Padan R. Pax6: a multi-level regulator of ocular development. Prog Retin Eye Res 2012; 31:351-76. [PMID: 22561546 DOI: 10.1016/j.preteyeres.2012.04.002] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 04/19/2012] [Accepted: 04/24/2012] [Indexed: 02/08/2023]
Abstract
Eye development has been a paradigm for the study of organogenesis, from the demonstration of lens induction through epithelial tissue morphogenesis, to neuronal specification and differentiation. The transcription factor Pax6 has been shown to play a key role in each of these processes. Pax6 is required for initiation of developmental pathways, patterning of epithelial tissues, activation of tissue-specific genes and interaction with other regulatory pathways. Herein we examine the data accumulated over the last few decades from extensive analyses of biochemical modules and genetic manipulation of the Pax6 gene. Specifically, we describe the regulation of Pax6's expression pattern, the protein's DNA-binding properties, and its specific roles and mechanisms of action at all stages of lens and retinal development. Pax6 functions at multiple levels to integrate extracellular information and execute cell-intrinsic differentiation programs that culminate in the specification and differentiation of a distinct ocular lineage.
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Affiliation(s)
- Ohad Shaham
- Sackler Faculty of Medicine, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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34
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Kim HT, Kim JW. Compartmentalization of vertebrate optic neuroephithelium: external cues and transcription factors. Mol Cells 2012; 33:317-24. [PMID: 22450691 PMCID: PMC3887801 DOI: 10.1007/s10059-012-0030-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 02/21/2012] [Accepted: 02/24/2012] [Indexed: 02/02/2023] Open
Abstract
The vertebrate eye is a laterally extended structure of the forebrain. It develops through a series of events, including specification and regionalization of the anterior neural plate, evagination of the optic vesicle (OV), and development of three distinct optic structures: the neural retina (NR), optic stalk (OS), and retinal pigment epithelium (RPE). Various external signals that act on the optic neuroepithelium in a spatial- and temporal-specific manner control the fates of OV subdomains by inducing localized expression of key transcription factors. Investigating the mechanisms underlying compartmentalization of these distinct optic neuroepithelium-derived tissues is therefore not only important from the standpoint of accounting for vertebrate eye morphogenesis, it is also helpful for understanding the fundamental basis of fate determination of other neuroectoderm- derived tissues. This review focuses on the molecular signatures of OV subdomains and the external factors that direct the development of tissues originating from the OV.
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Affiliation(s)
- Hyoung-Tai Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701,
Korea
| | - Jin Woo Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701,
Korea
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35
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Retinal neural progenitors express topographic map markers. Neurochem Int 2012; 61:859-65. [PMID: 22366647 DOI: 10.1016/j.neuint.2012.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 02/01/2012] [Accepted: 02/03/2012] [Indexed: 11/21/2022]
Abstract
Transplantation of neural stem cells for replacing neurons after neurodegeneration requires that the transplanted stem cells accurately reestablish the lost neural circuits in order to restore function. Retinal ganglion cell axons project to visual centers of the brain forming circuits in precise topographic order. In chick, dorsal retinal neurons project to ventral optic tectum, ventral neurons to dorsal tectum, anterior neurons to posterior tectum and posterior neurons to anterior tectum; forming a continuous point-to-point map of retinal cell position in the tectal projection. We found that when stem cells derived from ventral retina were implanted in dorsal host retina, the stem cells that became ganglion cells projected to dorsal tectum, appropriate for their site of origin in retina but not appropriate for their site of implant in retina. This led us to ask if retinal progenitors exhibit topographic markers of cell position in retina. Indeed, retinal neural progenitors express topographic markers: dorsal stem cells expressed more Ephrin B2 than ventral stem cells and, conversely, ventral stem cells expressed more Pax-2 and Ventroptin than dorsal stem cells. The fact that neural progenitors express topographic markers has pertinent implications in using neural stem cells in cell replacement therapy for replacing projecting neurons that express topographic order, e.g., analogous neurons of the visual, auditory, somatosensory and motor systems.
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36
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Atkinson-Leadbeater K, McFarlane S. Extrinsic factors as multifunctional regulators of retinal ganglion cell morphogenesis. Dev Neurobiol 2011; 71:1170-85. [DOI: 10.1002/dneu.20924] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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37
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Singh A, Tare M, Puli OR, Kango-Singh M. A glimpse into dorso-ventral patterning of the Drosophila eye. Dev Dyn 2011; 241:69-84. [PMID: 22034010 DOI: 10.1002/dvdy.22764] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2011] [Indexed: 12/15/2022] Open
Abstract
During organogenesis in all multi-cellular organisms, axial patterning is required to transform a single layer organ primordium into a three-dimensional organ. The Drosophila eye model serves as an excellent model to study axial patterning. Dorso-ventral (DV) axis determination is the first lineage restriction event during axial patterning of the Drosophila eye. The early Drosophila eye primordium has a default ventral fate, and the dorsal eye fate is established by onset of dorsal selector gene pannier (pnr) expression in a group of cells on the dorsal eye margin. The boundary between dorsal and ventral compartments called the equator is the site for Notch (N) activation, which triggers cell proliferation and differentiation. This review will focus on (1) chronology of events during DV axis determination; (2) how early division of eye into dorsal and ventral compartments contributes towards the growth and patterning of the fly retina, and (3) functions of DV patterning genes.
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Affiliation(s)
- Amit Singh
- Department of Biology, University of Dayton, Dayton, Ohio 45469, USA.
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38
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Lu J, Tsai T, Choo S, Yeh S, Tang R, Yang A, Lee H, Lu J. Induction of apoptosis and inhibition of cell growth by tbx5 knockdown contribute to dysmorphogenesis in Zebrafish embryos. J Biomed Sci 2011; 18:73. [PMID: 21982178 PMCID: PMC3199240 DOI: 10.1186/1423-0127-18-73] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Accepted: 10/08/2011] [Indexed: 12/28/2022] Open
Abstract
Background The tbx5 mutation in human causes Holt-Oram syndrome, an autosomal dominant condition characterized by a familial history of congenital heart defects and preaxial radial upper-limb defects. We report aberrant apoptosis and dormant cell growth over head, heart, trunk, fin, and tail of zebrafish embryos with tbx5 deficiency correspond to the dysmorphogenesis of tbx5 morphants. Methods Wild-type zebrafish embryos at the 1-cell stage were injected with 4.3 nl of 19.4 ng of tbx5 morpholino or mismatch-tbx5-MO respectively in tbx5 morphants and mismatched control group. Semi-quantitative RT-PCR was used to for expression analysis of apoptosis and cell cycle-related genes. TUNEL and immunohistochemical assay showed the apoptosis spots within the local tissues. Ultra-structure of cardiac myocardium was examined by transmission electron microscope. Results Apoptosis-related genes (bad, bax, and bcl2), and cell cycle-related genes (cdk2, pcna, p27, and p57) showed remarkable increases in transcriptional level by RT-PCR. Using a TUNEL and immnuohistochemical assay, apoptosis was observed in the organs including the head, heart, pectoral fins, trunk, and tail of tbx5 knockdown embryos. Under transmission electron microscopic examination, mitochondria in cardiomyocytes became swollen and the myocardium was largely disorganized with a disarrayed appearance, compatible with reduced enhancement of myosin in the cardiac wall. The ATP level was reduced, and the ADP/ATP ratio as an apoptotic index significantly increased in the tbx5 deficient embryos. Conclusion Our study highlighted that tbx5 deficiency evoked apoptosis, distributed on multiple organs corresponding to dysmorphogenesis with the shortage of promising maturation, in tbx5 knockdown zebrafish embryos. We hypothesized that mesenchymal cell apoptosis associated with altered TBX5 level may subsequently interfered with organogenesis and contributed to dysmorphogenesis in tbx5 deficiency zebrafish embryos.
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Affiliation(s)
- Jenher Lu
- Department of Pediatrics and Pathology, Taipei Veterans General Hospital, Taipei, Taiwan.
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Murali D, Kawaguchi-Niida M, Deng CX, Furuta Y. Smad4 is required predominantly in the developmental processes dependent on the BMP branch of the TGF-β signaling system in the embryonic mouse retina. Invest Ophthalmol Vis Sci 2011; 52:2930-7. [PMID: 21273545 DOI: 10.1167/iovs.10-5940] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The present study was aimed at defining developmental roles of Smad4, a key mediator of the TGF-β superfamily signaling system, in the embryonic mouse retina. METHODS Using a Cre/loxP-mediated conditional gene targeting approach, Smad4 gene function was deleted from the embryonic mouse retina. Mutant phenotypes were morphologically and molecularly examined. RESULTS Loss of Smad4 in the developing retina led to varying degrees of microphthalmia at birth, presumably because of elevated apoptosis observed transiently at embryonic day 12.5 in the developing retina. This was also associated with an apparent delay in accumulation of retinal ganglion cells. Smad4 conditional mutants also exhibited alterations of retinal spatial patterning along the dorsal-ventral axis, consistent with a known function of BMP signaling in the embryonic retina. However, despite a known role for BMP signaling in retinal cell survival, proliferation, and differentiation, Smad4 mutant retinal progenitor cells were capable of maintaining growth and neurogenesis throughout embryonic development. We also found that the loss of Smad4 led to abnormal targeting of retinal ganglion cell axons to the optic nerve head, a phenotype consistent with reduced BMP signaling in the developing retina. CONCLUSIONS These results suggest that Smad4 is essential for a subset of, but not all, TGF-β/BMP-dependent developmental processes in the embryonic retina. In addition, genetic requirements for Smad4 in the embryonic retina are evident predominantly in the developmental events regulated by the BMP branch of the TGF-β signaling pathway.
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Affiliation(s)
- Deepa Murali
- Department of Biochemistry and Molecular Biology, MD Anderson Cancer Center, University of Texas, Houston, Texas 77030, USA
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Lieven O, Rüther U. The Dkk1 dose is critical for eye development. Dev Biol 2011; 355:124-37. [PMID: 21539829 DOI: 10.1016/j.ydbio.2011.04.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 03/25/2011] [Accepted: 04/18/2011] [Indexed: 10/18/2022]
Abstract
During mammalian ocular development, several signaling pathways control the spatiotemporal highly defined realization of the three-dimensional eye architecture. Given the complexity of these inductive signals, the developing eye is a sensitive organ for several diseases. In this study, we investigated a Dkk1+/- haploinsufficiency during eye development, resulting in coloboma and anterior eye defects, two common developmental eye disorders. Dkk1 impacts eye development from a defined developmental time point on, and is critical for lens separation from the surface ectoderm via β-catenin mediated Pdgfrα and E-cadherin expression. Dkk1 does not impact the dorso ventral retina patterning in general but is critical for Shh dependent Pax2 extension into the midline region. The described results also indicate that the retinal Dkk1 dose is critical for important steps during eye development, such as optic fissure closure and cornea formation. Further analysis of the relationship between Dkk1 and Shh signaling revealed that Dkk1 and Shh coordinatively control anterior head formation and eye induction. During eye development itself, retinal Dkk1 activation is depending on cilia mediated Gli3 regulation. Therefore, our data essentially improve the knowledge of coloboma and anterior eye defects, which are common human eye developmental defects.
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Affiliation(s)
- Oliver Lieven
- Institute for Animal Developmental, Molecular Biology, Heinrich-Heine-University, Düsseldorf, Germany.
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Oros SM, Tare M, Kango-Singh M, Singh A. Dorsal eye selector pannier (pnr) suppresses the eye fate to define dorsal margin of the Drosophila eye. Dev Biol 2010; 346:258-71. [PMID: 20691679 PMCID: PMC2945442 DOI: 10.1016/j.ydbio.2010.07.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 07/26/2010] [Accepted: 07/27/2010] [Indexed: 12/28/2022]
Abstract
Axial patterning is crucial for organogenesis. During Drosophila eye development, dorso-ventral (DV) axis determination is the first lineage restriction event. The eye primordium begins with a default ventral fate, on which the dorsal eye fate is established by expression of the GATA-1 transcription factor pannier (pnr). Earlier, it was suggested that loss of pnr function induces enlargement in the dorsal eye due to ectopic equator formation. Interestingly, we found that in addition to regulating DV patterning, pnr suppresses the eye fate by downregulating the core retinal determination genes eyes absent (eya), sine oculis (so) and dacshund (dac) to define the dorsal eye margin. We found that pnr acts downstream of Ey and affects the retinal determination pathway by suppressing eya. Further analysis of the "eye suppression" function of pnr revealed that this function is likely mediated through suppression of the homeotic gene teashirt (tsh) and is independent of homothorax (hth), a negative regulator of eye. Pnr expression is restricted to the peripodial membrane on the dorsal eye margin, which gives rise to head structures around the eye, and pnr is not expressed in the eye disc proper that forms the retina. Thus, pnr has dual function, during early developmental stages pnr is involved in axial patterning whereas later it promotes the head specific fate. These studies will help in understanding the developmental regulation of boundary formation of the eye field on the dorsal eye margin.
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Affiliation(s)
- Sarah M. Oros
- Premedical Programs, University of Dayton, Dayton, OH 45469
- Department of Biology, University of Dayton, Dayton, OH 45469
| | - Meghana Tare
- Department of Biology, University of Dayton, Dayton, OH 45469
| | - Madhuri Kango-Singh
- Premedical Programs, University of Dayton, Dayton, OH 45469
- Department of Biology, University of Dayton, Dayton, OH 45469
- Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH 45469
| | - Amit Singh
- Premedical Programs, University of Dayton, Dayton, OH 45469
- Department of Biology, University of Dayton, Dayton, OH 45469
- Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH 45469
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Erickson T, French CR, Waskiewicz AJ. Meis1 specifies positional information in the retina and tectum to organize the zebrafish visual system. Neural Dev 2010; 5:22. [PMID: 20809932 PMCID: PMC2939508 DOI: 10.1186/1749-8104-5-22] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 09/01/2010] [Indexed: 01/17/2023] Open
Abstract
Background During visual system development, multiple signalling pathways cooperate to specify axial polarity within the retina and optic tectum. This information is required for the topographic mapping of retinal ganglion cell axons on the tectum. Meis1 is a TALE-class homeodomain transcription factor known to specify anterior-posterior identity in the hindbrain, but its role in visual system patterning has not been investigated. Results meis1 is expressed in both the presumptive retina and tectum. An analysis of retinal patterning reveals that Meis1 is required to correctly specify both dorsal-ventral and nasal-temporal identity in the zebrafish retina. Meis1-knockdown results in a loss of smad1 expression and an upregulation in follistatin expression, thereby causing lower levels of Bmp signalling and a partial ventralization of the retina. Additionally, Meis1-deficient embryos exhibit ectopic Fgf signalling in the developing retina and a corresponding loss of temporal identity. Meis1 also positively regulates ephrin gene expression in the tectum. Consistent with these patterning phenotypes, a knockdown of Meis1 ultimately results in retinotectal mapping defects. Conclusions In this work we describe a novel role for Meis1 in regulating Bmp signalling and in specifying temporal identity in the retina. By patterning both the retina and tectum, Meis1 plays an important role in establishing the retinotectal map and organizing the visual system.
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Affiliation(s)
- Timothy Erickson
- Department of Biological Sciences, University of Alberta, CW405, Biological Sciences Bldg, Edmonton T6G 2E9, Canada
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nev (cyfip2) is required for retinal lamination and axon guidance in the zebrafish retinotectal system. Dev Biol 2010; 344:784-94. [PMID: 20537992 DOI: 10.1016/j.ydbio.2010.05.512] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Accepted: 05/26/2010] [Indexed: 11/23/2022]
Abstract
In the zebrafish retinotectal system, retinal ganglion cells (RGCs) project topographically along anterior-posterior (A-P) and dorsal-ventral (D-V) axes to innervate their primary target, the optic tectum. In the nevermind (nev) mutant, D-V positional information is not maintained by dorsonasal retinal axons as they project through the optic tract to the tectum. Here we present a detailed phenotypic analysis of the retinotectal projection in nev and show that dorsonasal axons do eventually find their correct location on the tectum, albeit after taking a circuitous path. Interestingly, nev seems to be specifically required for retinal axons but not for several non-retinal axon tracts. In addition, we find that nev is required both cell autonomously and cell nonautonomously for proper lamination of the retina. We show that nev encodes Cyfip2 (Cytoplasmic FMRP interacting protein 2) and is thus the first known mutation in a vertebrate Cyfip family member. Finally, we show that CYFIP2 acts cell autonomously in the D-V sorting of dorsonasal RGC axons in the optic tract. CYFIP2 is a highly conserved protein that lacks known domains or structural motifs but has been shown to interact with Rac and the fragile-X mental retardation protein, suggesting intriguing links to cytoskeletal dynamics and RNA regulation.
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Pinter R, Hindges R. Perturbations of microRNA function in mouse dicer mutants produce retinal defects and lead to aberrant axon pathfinding at the optic chiasm. PLoS One 2010; 5:e10021. [PMID: 20386732 PMCID: PMC2850387 DOI: 10.1371/journal.pone.0010021] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 03/16/2010] [Indexed: 11/19/2022] Open
Abstract
Background During development axons encounter a variety of choice points where they have to make appropriate pathfinding decisions. The optic chiasm is a major decision point for retinal ganglion cell (RGC) axons en route to their target in order to ensure the correct wiring of the visual system. MicroRNAs (miRNAs) belong to the class of small non-coding RNA molecules and have been identified as important regulators of a variety of processes during embryonic development. However, their involvement in axon guidance decisions is less clear. Methodology/Principal Findings We report here that the early loss of Dicer, an essential protein for the maturation of miRNAs, in all cells of the forming retina and optic chiasm leads to severe phenotypes of RGC axon pathfinding at the midline. Using a conditional deletion approach in mice, we find in homozygous Dicer mutants a marked increase of ipsilateral projections, RGC axons extending outside the optic chiasm, the formation of a secondary optic tract and a substantial number of RGC axons projecting aberrantly into the contralateral eye. In addition, the mutant mice display a microphthalmia phenotype. Conclusions Our work demonstrates an important role of Dicer controlling the extension of RGC axons to the brain proper. It indicates that miRNAs are essential regulatory elements for mechanisms that ensure correct axon guidance decisions at the midline and thus have a central function in the establishment of circuitry during the development of the nervous system.
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Affiliation(s)
- Rita Pinter
- MRC Centre for Developmental Neurobiology, King's College London, Guy's Campus, London, United Kingdom
| | - Robert Hindges
- MRC Centre for Developmental Neurobiology, King's College London, Guy's Campus, London, United Kingdom
- * E-mail:
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Abstract
Whole genome duplication events are thought to have substantially contributed to organismal complexity, largely via divergent transcriptional regulation. Members of the vertebrate PAX2, PAX5 and PAX8 gene subfamily derived from an ancient class of paired box genes and arose from such whole genome duplication events. These genes are critical in establishing the midbrain-hindbrain boundary, specifying interneuron populations and for eye, ear and kidney development. Also PAX2 has adopted a unique role in pancreas development, whilst PAX5 is essential for early B-cell differentiation. The contribution of PAX258 genes to their collective role has diverged across paralogues and the animal lineages, resulting in a complex wealth of literature. It is now timely to provide a comprehensive comparative overview of these genes and their ancient and divergent roles. We also discuss their fundamental place within gene regulatory networks and the likely influence of cis-regulatory elements over their differential roles during early animal development.
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Affiliation(s)
- Debbie K Goode
- Queen Mary, University of London, School of Biological and Chemical Sciences, London, United Kingdom
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Kobayashi T, Yasuda K, Araki M. Coordinated regulation of dorsal bone morphogenetic protein 4 and ventral Sonic hedgehog signaling specifies the dorso-ventral polarity in the optic vesicle and governs ocular morphogenesis through fibroblast growth factor 8 upregulation. Dev Growth Differ 2010; 52:351-63. [PMID: 20298259 DOI: 10.1111/j.1440-169x.2010.01170.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dorsal and ventral specification in the early optic vesicle plays a crucial role in vertebrate ocular morphogenesis, and proper dorsal-ventral polarity in the optic vesicle ensures that distinct structures develop in separate domains within the eye primordium. The polarity is determined progressively during development by coordinated regulation of extraocular dorsal and ventral factors. In the present study, we cultured discrete portions of embryonic chick brains by preparing anterior cephalon, anterior dorsal cephalon and anterior ventral cephalon, and clearly demonstrate that bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) constitute a dorsal-ventral signaling system together with fibroblast growth factor 8 (FGF8). BMP4 and Shh upregulate Tbx5 and Pax2, as reported previously, and at the same time Shh downregulates Tbx5, while BMP4 affects Pax2 expression to downregulate similarly. Shh induces Fgf8 expression in the ventral optic vesicle. This, in turn, determines the distinct boundary of the retinal pigmented epithelium and the neural retina by suppressing Mitf expression. The lens develops only when signals from both the dorsal and ventral regions come across together. Inverted deposition of Shh and BMP4 signals in organ-cultured optic vesicle completely re-organized ocular structures to be inverted. Based on these observations we propose a novel model in which the two signals govern the whole of ocular development when they encounter each other in the ocular morphogenic domain.
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Affiliation(s)
- Takuma Kobayashi
- Developmental Neurobiology Laboratory, Department of Biological Sciences, Nara Women's University, Nara, Japan
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Yun S, Saijoh Y, Hirokawa KE, Kopinke D, Murtaugh LC, Monuki ES, Levine EM. Lhx2 links the intrinsic and extrinsic factors that control optic cup formation. Development 2009; 136:3895-906. [PMID: 19906857 DOI: 10.1242/dev.041202] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A crucial step in eye organogenesis is the transition of the optic vesicle into the optic cup. Several transcription factors and extracellular signals mediate this transition, but whether a single factor links them into a common genetic network is unclear. Here, we provide evidence that the LIM homeobox gene Lhx2, which is expressed in the optic neuroepithelium, fulfils such a role. In Lhx2(-/-) mouse embryos, eye field specification and optic vesicle morphogenesis occur, but development arrests prior to optic cup formation in both the optic neuroepithelium and lens ectoderm. This is accompanied by failure to maintain or initiate the expression patterns of optic-vesicle-patterning and lens-inducing determinants. Of the signaling pathways examined, only BMP signaling is noticeably altered and Bmp4 and Bmp7 mRNAs are undetectable. Lhx2(-/-) optic vesicles and lens ectoderm upregulate Pax2, Fgf15 and Sox2 in response to BMP treatments, and Lhx2 genetic mosaics reveal that transcription factors, including Vsx2 and Mitf, require Lhx2 cell-autonomously for their expression. Our data indicate that Lhx2 is required for optic vesicle patterning and lens formation in part by regulating BMP signaling in an autocrine manner in the optic neuroepithelium and in a paracrine manner in the lens ectoderm. We propose a model in which Lhx2 is a central link in a genetic network that coordinates the multiple pathways leading to optic cup formation.
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Affiliation(s)
- Sanghee Yun
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
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The spatial patterning of mouse cone opsin expression is regulated by bone morphogenetic protein signaling through downstream effector COUP-TF nuclear receptors. J Neurosci 2009; 29:12401-11. [PMID: 19812316 DOI: 10.1523/jneurosci.0951-09.2009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cone photopigments, known as opsins, are pivotal elements and the first detection module used in color vision. In mice, cone photoreceptors are distributed throughout the retina, and short-wavelength (S) and medium-wavelength (M) opsins have unique expression patterns in the retina with a gradient along the dorsoventral axis; however, the mechanisms regulating the spatial patterning of cone opsin expression have not been well documented. The purpose of this study was to define the mechanisms regulating the spatial patterning of cone opsin expression. By analyzing knock-outs for bone morphogenetic protein (BMP) signaling, we found an essential role for BMP in forming cone opsin expression patterns in the retina; however, BMP signaling is activated only transiently in the dorsal half of the retina during early retinal development. Thus, BMP is not likely to play a direct role in opsin gene expression, which starts at a later stage of retinal development. We identified the chicken ovalbumin upstream promoter-transcription factor (COUP-TF) nuclear receptor as a link between BMP and opsin expression. BMP signaling is essential for the correct dorsoventral spatial expression of COUP-TFI and COUP-TFII. Through gain- and loss-of-function analyses, we found that both COUP-TFI and COUP-TFII are required to suppress S-opsin expression in the dorsal retina but that only COUP-TFI plays an essential role in suppressing M-opsin expression in the ventral retina. Based on these findings, we propose a new molecular cascade involving BMP and COUP-TFs that conveys dorsoventral information to direct the expression of cone opsins during retinal development.
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Harada H, Takahashi Y, Kawakami K, Ogura T, Nakamura H. Tracing retinal fiber trajectory with a method of transposon-mediated genomic integration in chick embryo. Dev Growth Differ 2009; 50:697-702. [PMID: 18826475 DOI: 10.1111/j.1440-169x.2008.01067.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We report convenient retinal fiber tracing by transfecting the tracer cDNA by in ovo electroporation. Long-term and stable expression of tracer proteins such as green fluorescent protein is achieved by transposon-mediated genome integration of the tracer protein expression cassette. We carried out coelectroporation of a plasmid containing CAGGS-tracer cDNA flanked by the Tol2 transposable element along with a transposase expression vector to the optic vesicle of chick embryos at stage 11. By selecting electrodes, we can label a large group of retinal ganglion cells, or a small group of retinal ganglion cells; parallel electrodes assure transfection of large areas of the retina, and needle type electrodes label small areas of the retina. The retinal fiber trajectory and terminal zone (TZ) could be detected in the precise retinotopic manner on the contra-lateral side of the optic tectum. The method has advantage in that we can show the retinal fiber trajectory in relation to the molecules that are responsible for pathfinding for the retinal fibers in the same specimen.
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Affiliation(s)
- Hidekiyo Harada
- Department of Molecular Neurobiology, Graduate School of Life Sciences and Institute of Development, Aging and Cancer, Tohoku University, Seiryo-machi 4-1, Aoba-ku, Sendai 980-8575, Japan
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Zhao L, Saitsu H, Sun X, Shiota K, Ishibashi M. Sonic hedgehog is involved in formation of the ventral optic cup by limiting Bmp4 expression to the dorsal domain. Mech Dev 2009; 127:62-72. [PMID: 19854269 DOI: 10.1016/j.mod.2009.10.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 09/09/2009] [Accepted: 10/20/2009] [Indexed: 11/20/2022]
Abstract
Accumulating evidence suggests that Sonic hedgehog (Shh) signaling plays a crucial role in eye vesicle patterning in vertebrates. Shh promotes expression of Pax2 in the optic stalk and represses expression of Pax6 in the optic cup. Shh signaling contributes to establishment of both proximal-distal and dorsal-ventral axes by activating Vax1, Vax2, and Pax2. In the dorsal part of the developing retina, Bmp4 is expressed and antagonizes the ventralizing effects of Shh signaling through the activation of Tbx5 expression in chick and Xenopus. To examine the roles of Shh signaling in optic cup formation and optic stalk development, we utilized the Smoothened (Smo) conditional knockout (CKO) mouse line. Smo is a membrane protein which mediates Shh signaling into inside of cells. Cre expression was driven by Fgf15 enhancer. The ventral evagination of the optic cup deteriorated from E10 in the Smo-CKO, whereas the dorsal optic cup and optic stalk develop normally until E11. We analyzed expression of various genes such as Pax family (Pax2/Pax6), Vax family (Vax1/Vax2) and Bmp4. Bmp4 expression was greatly upregulated in the optic vesicle by the 21-somite stage. Then Vax1/2 expression was decreased at the 20- to 24-somite stages. Pax2/6 expression was affected at the 27- to 32-somite stages. Our data suggest that the effects of the absence of Shh signaling on Vax1/Vax2 are mediated through increased Bmp4 expression throughout the optic cup. Also unchanged patterns of Raldh2 and Raldh3 suggest that retinoic acid is not the downstream to Shh signaling to control the ventral optic cup morphology.
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Affiliation(s)
- Lanying Zhao
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Yoshida, Sakyo-ku, Kyoto, Japan
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