1
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Casey MA, Lusk S, Kwan KM. Eye Morphogenesis in Vertebrates. Annu Rev Vis Sci 2023; 9:221-243. [PMID: 37040791 DOI: 10.1146/annurev-vision-100720-111125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Proper eye structure is essential for visual function: Multiple essential eye tissues must take shape and assemble into a precise three-dimensional configuration. Accordingly, alterations to eye structure can lead to pathological conditions of visual impairment. Changes in eye shape can also be adaptive over evolutionary time. Eye structure is first established during development with the formation of the optic cup, which contains the neural retina, retinal pigment epithelium, and lens. This crucial yet deceptively simple hemispherical structure lays the foundation for all later elaborations of the eye. Building on descriptions of the embryonic eye that started with hand drawings and micrographs, the field is beginning to identify mechanisms driving dynamic changes in three-dimensional cell and tissue shape. A combination of molecular genetics, imaging, and pharmacological approaches is defining connections among transcription factors, signaling pathways, and the intracellular machinery governing the emergence of this crucial structure.
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Affiliation(s)
- Macaulie A Casey
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA; , ,
| | - Sarah Lusk
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA; , ,
| | - Kristen M Kwan
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA; , ,
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2
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Amel A, Rabeling A, Rossouw S, Goolam M. Wnt and BMP signalling direct anterior-posterior differentiation in aggregates of mouse embryonic stem cells. Biol Open 2023; 12:bio059981. [PMID: 37622734 PMCID: PMC10508691 DOI: 10.1242/bio.059981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 08/22/2023] [Indexed: 08/26/2023] Open
Abstract
Stem-cell-based embryo models have allowed greater insight into peri-implantation mammalian developmental events that are otherwise difficult to manipulate due to the inaccessibility of the early embryo. The rapid development of this field has resulted in the precise roles of frequently used supplements such as N2, B27 and Chiron in driving stem cell lineage commitment not being clearly defined. Here, we investigate the effects of these supplements on embryoid bodies to better understand their roles in stem cell differentiation. We show that Wnt signalling has a general posteriorising effect on stem cell aggregates and directs differentiation towards the mesoderm, as confirmed through the upregulation of posterior and mesodermal markers. N2 and B27 can mitigate these effects and upregulate the expression of anterior markers. To control the Wnt gradient and the subsequent anterior versus posterior fate, we make use of a BMP4 signalling centre and show that aggregates in these conditions express cephalic markers. These findings indicate that there is an intricate balance between various culture supplements and their ability to guide differentiation in stem cell embryo models.
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Affiliation(s)
- Atoosa Amel
- Department of Human Biology, University of Cape Town, Cape Town 7925, South Africa
| | - Alexa Rabeling
- Department of Human Biology, University of Cape Town, Cape Town 7925, South Africa
| | - Simoné Rossouw
- Department of Human Biology, University of Cape Town, Cape Town 7925, South Africa
| | - Mubeen Goolam
- Department of Human Biology, University of Cape Town, Cape Town 7925, South Africa
- UCT Neuroscience Institute, Cape Town, South Africa
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3
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Daruich A, Duncan M, Robert MP, Lagali N, Semina EV, Aberdam D, Ferrari S, Romano V, des Roziers CB, Benkortebi R, De Vergnes N, Polak M, Chiambaretta F, Nischal KK, Behar-Cohen F, Valleix S, Bremond-Gignac D. Congenital aniridia beyond black eyes: From phenotype and novel genetic mechanisms to innovative therapeutic approaches. Prog Retin Eye Res 2023; 95:101133. [PMID: 36280537 PMCID: PMC11062406 DOI: 10.1016/j.preteyeres.2022.101133] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
Congenital PAX6-aniridia, initially characterized by the absence of the iris, has progressively been shown to be associated with other developmental ocular abnormalities and systemic features making congenital aniridia a complex syndromic disorder rather than a simple isolated disease of the iris. Moreover, foveal hypoplasia is now recognized as a more frequent feature than complete iris hypoplasia and a major visual prognosis determinant, reversing the classical clinical picture of this disease. Conversely, iris malformation is also a feature of various anterior segment dysgenesis disorders caused by PAX6-related developmental genes, adding a level of genetic complexity for accurate molecular diagnosis of aniridia. Therefore, the clinical recognition and differential genetic diagnosis of PAX6-related aniridia has been revealed to be much more challenging than initially thought, and still remains under-investigated. Here, we update specific clinical features of aniridia, with emphasis on their genotype correlations, as well as provide new knowledge regarding the PAX6 gene and its mutational spectrum, and highlight the beneficial utility of clinically implementing targeted Next-Generation Sequencing combined with Whole-Genome Sequencing to increase the genetic diagnostic yield of aniridia. We also present new molecular mechanisms underlying aniridia and aniridia-like phenotypes. Finally, we discuss the appropriate medical and surgical management of aniridic eyes, as well as innovative therapeutic options. Altogether, these combined clinical-genetic approaches will help to accelerate time to diagnosis, provide better determination of the disease prognosis and management, and confirm eligibility for future clinical trials or genetic-specific therapies.
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Affiliation(s)
- Alejandra Daruich
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Melinda Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Matthieu P Robert
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; Borelli Centre, UMR 9010, CNRS-SSA-ENS Paris Saclay-Paris Cité University, Paris, France
| | - Neil Lagali
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Faculty of Medicine, Linköping University, 581 83, Linköping, Sweden; Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway
| | - Elena V Semina
- Department of Pediatrics, Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI, 53226, USA
| | - Daniel Aberdam
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Stefano Ferrari
- Fondazione Banca degli Occhi del Veneto, Via Paccagnella 11, Venice, Italy
| | - Vito Romano
- Department of Medical and Surgical Specialties, Radiolological Sciences, and Public Health, Ophthalmology Clinic, University of Brescia, Italy
| | - Cyril Burin des Roziers
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP. Centre Université de Paris, Fédération de Génétique et de Médecine Génomique Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris Cedex 14, France
| | - Rabia Benkortebi
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France
| | - Nathalie De Vergnes
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France
| | - Michel Polak
- Pediatric Endocrinology, Gynecology and Diabetology, Hôpital Universitaire Necker Enfants Malades, AP-HP, Paris Cité University, INSERM U1016, Institut IMAGINE, France
| | | | - Ken K Nischal
- Division of Pediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA; UPMC Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Francine Behar-Cohen
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Sophie Valleix
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP. Centre Université de Paris, Fédération de Génétique et de Médecine Génomique Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris Cedex 14, France
| | - Dominique Bremond-Gignac
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France.
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4
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D'Oria F, Barraquer R, Alio JL. Crystalline lens alterations in congenital aniridia. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2021; 96 Suppl 1:38-51. [PMID: 34836587 DOI: 10.1016/j.oftale.2020.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/15/2020] [Indexed: 06/13/2023]
Abstract
Congenital aniridia is a rare genetic disease associated with mutations in the PAX6 gene. Changes in the lens in aniridia can be alterations of size and shape, of position - which generally reveal zonular weakness and determines subluxation of the lens - and mainly changes in transparency, cataracts, with variable morphology of polar, cortical, subcapsular, lamellar, and more rarely, nuclear cataract. Visual acuity and quality of vision in patients with congenital aniridia complicated by cataracts can be improved by carefully planned surgery, when lack of media transparency justifies surgical indication. Most patients have some improvement in visual acuity and quality of retinal image. Cataract surgery with aniridia is complicated by pathological changes due to the underlying cause of the aniridia. Challenges include corneal opacification, friable capsule and, above all, iris and pupil reconstruction. It can also determine late complications, such as secondary glaucoma or deterioration of pre-existent glaucoma, and corneal endothelial decompensation. After crystalline lens surgery in these patients, either by cataract or dislocation, for visual rehabilitation there are various techniques such as keratopigmentation, prosthetic iris devices or Morcher intraocular lenses with a black diaphragm. An appropriate individualised surgical plan should be selected depending on patient and surgical experience, in order to minimise complications and give the best chance of postoperative success.
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Affiliation(s)
- F D'Oria
- Vissum Innovation, Alicante, Spain; Department of Basic Medical Science, Neuroscience and Sense Organs, University of Bari, Bari, Italy
| | - R Barraquer
- Instituto Universitario Barraquer, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - J L Alio
- Vissum Innovation, Alicante, Spain; División de Oftalmología, Universidad Miguel Hernández, Alicante, Spain.
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5
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Gandhi S, Li Y, Tang W, Christensen JB, Urrutia HA, Vieceli FM, Piacentino ML, Bronner ME. A single-plasmid approach for genome editing coupled with long-term lineage analysis in chick embryos. Development 2021; 148:dev193565. [PMID: 33688075 PMCID: PMC8077534 DOI: 10.1242/dev.193565] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 02/23/2021] [Indexed: 12/12/2022]
Abstract
An important strategy for establishing mechanisms of gene function during development is through mutation of individual genes and analysis of subsequent effects on cell behavior. Here, we present a single-plasmid approach for genome editing in chick embryos to study experimentally perturbed cells in an otherwise normal embryonic environment. To achieve this, we have engineered a plasmid that encodes Cas9 protein, gene-specific guide RNA (gRNA), and a fluorescent marker within the same construct. Using transfection- and electroporation-based approaches, we show that this construct can be used to perturb gene function in early embryos as well as human cell lines. Importantly, insertion of this cistronic construct into replication-incompetent avian retroviruses allowed us to couple gene knockouts with long-term lineage analysis. We demonstrate the application of our newly engineered constructs and viruses by perturbing β-catenin in vitro and Sox10, Pax6 and Pax7 in the neural crest, retina, and neural tube and segmental plate in vivo, respectively. Together, this approach enables genes of interest to be knocked out in identifiable cells in living embryos and can be broadly applied to numerous genes in different embryonic tissues.
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Affiliation(s)
- Shashank Gandhi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yuwei Li
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Weiyi Tang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jens B. Christensen
- Department of Neuroscience, University of Copenhagen, Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Hugo A. Urrutia
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Felipe M. Vieceli
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michael L. Piacentino
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marianne E. Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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6
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D'Oria F, Barraquer R, Alio JL. Crystalline lens alterations in congenital aniridia. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2021; 96:S0365-6691(21)00028-9. [PMID: 33612366 DOI: 10.1016/j.oftal.2020.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 11/27/2022]
Abstract
Congenital aniridia is a rare genetic disease associated with mutations in the PAX6 gene. Changes in the lens in aniridia can be alterations of size and shape, of position - which generally reveal zonular weakness and determines subluxation of the lens - and mainly changes in transparency, cataracts, with variable morphology of polar, cortical, subcapsular, lamellar, and more rarely, nuclear cataract. Visual acuity and quality of vision in patients with congenital aniridia complicated by cataracts can be improved by carefully planned surgery, when lack of media transparency justifies surgical indication. Most patients have some improvement in visual acuity and quality of retinal image. Cataract surgery with aniridia is complicated by pathological changes due to the underlying cause of the aniridia. Challenges include corneal opacification, friable capsule and, above all, iris and pupil reconstruction. It can also determine late complications, such as secondary glaucoma or deterioration of pre-existent glaucoma, and corneal endothelial decompensation. After crystalline lens surgery in these patients, either by cataract or dislocation, for visual rehabilitation there are various techniques such as keratopigmentation, prosthetic iris devices or Morcher intraocular lenses with a black diaphragm. An appropriate individualised surgical plan should be selected depending on patient and surgical experience, in order to minimise complications and give the best chance of postoperative success.
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Affiliation(s)
- F D'Oria
- Vissum Innovation, Alicante, España; Department of Basic Medical Science, Neuroscience and Sense Organs, University of Bari, Bari, Italia
| | - R Barraquer
- Instituto Universitario Barraquer, Universitat Autònoma de Barcelona, Barcelona, España
| | - J L Alio
- Vissum Innovation, Alicante, España; División de Oftalmología, Universidad Miguel Hernández, Alicante, España.
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7
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Weigele J, Bohnsack BL. Genetics Underlying the Interactions between Neural Crest Cells and Eye Development. J Dev Biol 2020; 8:jdb8040026. [PMID: 33182738 PMCID: PMC7712190 DOI: 10.3390/jdb8040026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/03/2020] [Accepted: 11/07/2020] [Indexed: 12/14/2022] Open
Abstract
The neural crest is a unique, transient stem cell population that is critical for craniofacial and ocular development. Understanding the genetics underlying the steps of neural crest development is essential for gaining insight into the pathogenesis of congenital eye diseases. The neural crest cells play an under-appreciated key role in patterning the neural epithelial-derived optic cup. These interactions between neural crest cells within the periocular mesenchyme and the optic cup, while not well-studied, are critical for optic cup morphogenesis and ocular fissure closure. As a result, microphthalmia and coloboma are common phenotypes in human disease and animal models in which neural crest cell specification and early migration are disrupted. In addition, neural crest cells directly contribute to numerous ocular structures including the cornea, iris, sclera, ciliary body, trabecular meshwork, and aqueous outflow tracts. Defects in later neural crest cell migration and differentiation cause a constellation of well-recognized ocular anterior segment anomalies such as Axenfeld–Rieger Syndrome and Peters Anomaly. This review will focus on the genetics of the neural crest cells within the context of how these complex processes specifically affect overall ocular development and can lead to congenital eye diseases.
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Affiliation(s)
- Jochen Weigele
- Division of Ophthalmology, Ann & Robert H. Lurie Children’s Hospital of Chicago, 225 E. Chicago Ave, Chicago, IL 60611, USA;
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, 645 N. Michigan Ave, Chicago, IL 60611, USA
| | - Brenda L. Bohnsack
- Division of Ophthalmology, Ann & Robert H. Lurie Children’s Hospital of Chicago, 225 E. Chicago Ave, Chicago, IL 60611, USA;
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, 645 N. Michigan Ave, Chicago, IL 60611, USA
- Correspondence: ; Tel.: +1-312-227-6180; Fax: +1-312-227-9411
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8
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Craenen K, Verslegers M, Craeghs L, Quintens R, Janssen A, Coolkens A, Baatout S, Moons L, Benotmane MA. Abnormal retinal pigment epithelium melanogenesis as a major determinant for radiation-induced congenital eye defects. Reprod Toxicol 2019; 91:59-73. [PMID: 31705956 DOI: 10.1016/j.reprotox.2019.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/30/2019] [Accepted: 10/07/2019] [Indexed: 01/26/2023]
Abstract
Recent studies highlighted a link between ionizing radiation exposure during neurulation and birth defects such as microphthalmos and anophthalmos. Because the mechanisms underlying these defects remain largely unexplored, we irradiated pregnant C57BL/6J mice (1.0 Gy, X-rays) at embryonic day (E)7.5, followed by histological and gene/protein expression analyses at defined days. Irradiation impaired embryonic development at E9 and we observed a delayed pigmentation of the retinal pigment epithelium (RPE) at E11. In addition, a reduced RNA expression and protein abundance of critical eye-development genes (e.g. Pax6 and Lhx2) was observed. Furthermore, a decreased expression of Mitf, Tyr and Tyrp1 supported the radiation-induced perturbation in RPE pigmentation. Finally, via immunostainings for proliferation (Ki67) and mitosis (phosphorylated histone 3), a decreased mitotic index was observed in the E18 retina after exposure at E7.5. Overall, we propose a plausible etiological model for radiation-induced eye-size defects, with RPE melanogenesis as a major determining factor.
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Affiliation(s)
- Kai Craenen
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium; Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology section, Department of Biology, Faculty of Science, KU Leuven, Naamsestraat 61 bus 2464, Leuven 3000, Belgium
| | - Mieke Verslegers
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium
| | - Livine Craeghs
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium; Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology section, Department of Biology, Faculty of Science, KU Leuven, Naamsestraat 61 bus 2464, Leuven 3000, Belgium
| | - Roel Quintens
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium
| | - Ann Janssen
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium
| | - Amelie Coolkens
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium
| | - Sarah Baatout
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology section, Department of Biology, Faculty of Science, KU Leuven, Naamsestraat 61 bus 2464, Leuven 3000, Belgium
| | - Mohammed Abderrafi Benotmane
- Radiobiology Unit, Interdisciplinary Biosciences, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, Mol 2400, Belgium.
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9
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The peripheral eye: A neurogenic area with potential to treat retinal pathologies? Prog Retin Eye Res 2018; 68:110-123. [PMID: 30201383 DOI: 10.1016/j.preteyeres.2018.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 08/31/2018] [Accepted: 09/03/2018] [Indexed: 12/14/2022]
Abstract
Numerous degenerative diseases affecting visual function, including glaucoma and retinitis pigmentosa, are produced by the loss of different types of retinal cells. Cell replacement therapy has emerged as a promising strategy for treating these and other retinal diseases. The retinal margin or ciliary body (CB) of mammals has been proposed as a potential source of cells to be used in degenerative conditions affecting the retina because it has been reported it might hold neurogenic potential beyond embryonic development. However, many aspects of the origin and biology of the CB are unknown and more recent experiments have challenged the capacity of CB cells to generate different types of retinal neurons. Here we review the most recent findings about the development of the marginal zone of the retina in different vertebrates and some of the mechanisms underlying the proliferative and neurogenic capacity of this fascinating region of the vertebrates eye. In addition, we performed experiments to isolate CB cells from the mouse retina, generated neurospheres and observed that they can be expanded with a proliferative ratio similar to neural stem cells. When induced to differentiate, cells derived from the CB neurospheres start to express early neural markers but, unlike embryonic stem cells, they are not able to fully differentiate in vitro or generate retinal organoids. Together with previous reports on the neurogenic capacity of CB cells, also reviewed here, our results contribute to the current knowledge about the potentiality of this peripheral region of the eye as a therapeutic source of functional retinal neurons in degenerative diseases.
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10
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Cavodeassi F, Creuzet S, Etchevers HC. The hedgehog pathway and ocular developmental anomalies. Hum Genet 2018; 138:917-936. [PMID: 30073412 PMCID: PMC6710239 DOI: 10.1007/s00439-018-1918-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/24/2018] [Indexed: 12/18/2022]
Abstract
Mutations in effectors of the hedgehog signaling pathway are responsible for a wide variety of ocular developmental anomalies. These range from massive malformations of the brain and ocular primordia, not always compatible with postnatal life, to subtle but damaging functional effects on specific eye components. This review will concentrate on the effects and effectors of the major vertebrate hedgehog ligand for eye and brain formation, Sonic hedgehog (SHH), in tissues that constitute the eye directly and also in those tissues that exert indirect influence on eye formation. After a brief overview of human eye development, the many roles of the SHH signaling pathway during both early and later morphogenetic processes in the brain and then eye and periocular primordia will be evoked. Some of the unique molecular biology of this pathway in vertebrates, particularly ciliary signal transduction, will also be broached within this developmental cellular context.
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Affiliation(s)
- Florencia Cavodeassi
- Institute for Medical and Biomedical Education, St. George´s University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Sophie Creuzet
- Institut des Neurosciences Paris-Saclay (Neuro-PSI), UMR 9197, CNRS, Université Paris-Sud, 1 Avenue de la Terrasse, 91198, Gif-sur-Yvette Cedex, France
| | - Heather C Etchevers
- Aix-Marseille Univ, Marseille Medical Genetics (MMG), INSERM, Faculté de Médecine, 27 boulevard Jean Moulin, 13005, Marseille, France.
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11
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Ren X, Hamilton N, Müller F, Yamamoto Y. Cellular rearrangement of the prechordal plate contributes to eye degeneration in the cavefish. Dev Biol 2018; 441:221-234. [PMID: 30031755 DOI: 10.1016/j.ydbio.2018.07.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 07/16/2018] [Accepted: 07/18/2018] [Indexed: 12/23/2022]
Abstract
Astyanax mexicanus consists of two different populations: a sighted surface-dwelling form (surface fish) and a blind cave-dwelling form (cavefish). In the cavefish, embryonic expression of sonic hedgehog a (shha) in the prechordal plate is expanded towards the anterior midline, which has been shown to contribute to cavefish specific traits such as eye degeneration, enhanced feeding apparatus, and specialized brain anatomy. However, it is not clear how this expanded expression is achieved and which signaling pathways are involved. Nodal signaling has a crucial role for expression of shh and formation of the prechordal plate. In this study, we report increased expression of prechordal plate marker genes, nodal-related 2 (ndr2) and goosecoid (gsc) in cavefish embryos at the tailbud stage. To investigate whether Nodal signaling is responsible for the anterior expansion of the prechordal plate, we used an inhibitor of Nodal signaling and showed a decreased anterior expansion of the prechordal plate and increased pax6 expression in the anterior midline in treated cavefish embryos. Later in development, the lens and optic cup of treated embryos were significantly larger than untreated embryos. Conversely, increasing Nodal signaling in the surface fish embryo resulted in the expansion of anterior prechordal plate and reduction of pax6 expression in the anterior neural plate together with the formation of small lenses and optic cups later in development. These results confirmed that Nodal signaling has a crucial role for the anterior expansion of the prechordal plate and plays a significant role in cavefish eye development. We showed that the anterior expansion of the prechordal plate was not due to increased total cell number, suggesting the expansion is achieved by changes in cellular distribution in the prechordal plate. In addition, the distribution of presumptive prechordal plate cells in Spemann's organiser was also altered in the cavefish. These results suggested that changes in the cellular arrangement of Spemann's organiser in early gastrulae could have an essential role in the anterior expansion of the prechordal plate contributing to eye degeneration in the cavefish.
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Affiliation(s)
- Xiaoyun Ren
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Noémie Hamilton
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Ferenc Müller
- Institute of Cancer and Genomics Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Yoshiyuki Yamamoto
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.
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Generation of Retinal Organoids with Mature Rods and Cones from Urine-Derived Human Induced Pluripotent Stem Cells. Stem Cells Int 2018; 2018:4968658. [PMID: 30008752 PMCID: PMC6020468 DOI: 10.1155/2018/4968658] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/07/2018] [Indexed: 12/18/2022] Open
Abstract
Urine cells, a body trash, have been successfully reprogrammed into human induced pluripotent stem cells (U-hiPSCs) which hold a huge promise in regenerative medicine. However, it is unknown whether or to what extent U-hiPSCs can generate retinal cells so far. With a modified retinal differentiation protocol without addition of retinoic acid (RA), our study revealed that U-hiPSCs were able to differentiate towards retinal fates and form 3D retinal organoids containing laminated neural retina with all retinal cell types located in proper layer as in vivo. More importantly, U-hiPSCs generated highly mature photoreceptors with all subtypes, even red/green cone-rich photoreceptors. Our data indicated that a supplement of RA to culture medium was not necessary for maturation and specification of U-hiPSC-derived photoreceptors at least in the niche of retinal organoids. The success of retinal differentiation with U-hiPSCs provides many opportunities in cell therapy, disease modeling, and drug screening, especially in personalized medicine of retinal diseases since urine cells can be noninvasively collected from patients and their relatives.
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Phenotypic Variation in a Four-Generation Family with Aniridia Carrying a Novel PAX6 Mutation. J Ophthalmol 2018; 2018:5978293. [PMID: 29850208 PMCID: PMC5904767 DOI: 10.1155/2018/5978293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/05/2018] [Indexed: 12/14/2022] Open
Abstract
Aniridia is a congenital disease that affects almost all eye structures and is primarily caused by loss-of-function mutations in the PAX6 gene. The degree of vision loss in aniridia varies and is dependent on the extent of foveal, iris, and optic nerve hypoplasia and the presence of glaucoma, cataracts, and corneal opacification. Here, we describe a 4-generation family in which 7 individuals across 2 generations carry a novel disease-causing frameshift mutation (NM_000280.4(PAX6):c.565TC>T) in PAX6. This mutation results in an early stop codon in exon 8, which is predicted to cause nonsense-mediated decay of the truncated mRNA and a functionally null PAX6 allele. Family members with aniridia showed differences in multiple eye phenotypes including iris and optic nerve hypoplasia, congenital and acquired corneal opacification, glaucoma, and strabismus. Visual acuity ranged from 20/100 to less than 20/800. Patients who required surgical intervention for glaucoma or corneal opacification had worse visual outcomes. Our results show that family members carrying a novel PAX6 frameshift mutation have variable expressivity, leading to different ocular comorbidities and visual outcomes.
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Abstract
Paired box protein 6 (PAX6) is a master regulator of the eye development. Over the last past two decades, our understanding of eye development, especially the molecular function of PAX6, has focused on transcriptional control of the Pax6 expression. However, other regulatory mechanisms for gene expression, including alternative splicing (AS), have been understudied in the eye development. Recent findings suggest that two PAX6 isoforms generated by AS of Pax6 pre-mRNA may play previously underappreciated role(s) during eye development, especially, the corneal development.
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Affiliation(s)
- Jung Woo Park
- Faculty of Health Sciences, University of Macau , Macau, China
| | - Juan Yang
- Faculty of Health Sciences, University of Macau , Macau, China
| | - Ren-He Xu
- Faculty of Health Sciences, University of Macau , Macau, China
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15
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Wisely CE, Sayed JA, Tamez H, Zelinka C, Abdel-Rahman MH, Fischer AJ, Cebulla CM. The chick eye in vision research: An excellent model for the study of ocular disease. Prog Retin Eye Res 2017; 61:72-97. [PMID: 28668352 PMCID: PMC5653414 DOI: 10.1016/j.preteyeres.2017.06.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 06/24/2017] [Accepted: 06/27/2017] [Indexed: 02/06/2023]
Abstract
The domestic chicken, Gallus gallus, serves as an excellent model for the study of a wide range of ocular diseases and conditions. The purpose of this manuscript is to outline some anatomic, physiologic, and genetic features of this organism as a robust animal model for vision research, particularly for modeling human retinal disease. Advantages include a sequenced genome, a large eye, relative ease of handling and maintenance, and ready availability. Relevant similarities and differences to humans are highlighted for ocular structures as well as for general physiologic processes. Current research applications for various ocular diseases and conditions, including ocular imaging with spectral domain optical coherence tomography, are discussed. Several genetic and non-genetic ocular disease models are outlined, including for pathologic myopia, keratoconus, glaucoma, retinal detachment, retinal degeneration, ocular albinism, and ocular tumors. Finally, the use of stem cell technology to study the repair of damaged tissues in the chick eye is discussed. Overall, the chick model provides opportunities for high-throughput translational studies to more effectively prevent or treat blinding ocular diseases.
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Affiliation(s)
- C Ellis Wisely
- Havener Eye Institute, Department of Ophthalmology and Visual Science, The Ohio State University Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, USA
| | - Javed A Sayed
- Havener Eye Institute, Department of Ophthalmology and Visual Science, The Ohio State University Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, USA
| | - Heather Tamez
- Havener Eye Institute, Department of Ophthalmology and Visual Science, The Ohio State University Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, USA
| | - Chris Zelinka
- Department of Neuroscience, The Ohio State University Wexner Medical Center, 333 West 10th Avenue, Columbus, OH 43210, USA
| | - Mohamed H Abdel-Rahman
- Havener Eye Institute, Department of Ophthalmology and Visual Science, The Ohio State University Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, USA
| | - Andy J Fischer
- Department of Neuroscience, The Ohio State University Wexner Medical Center, 333 West 10th Avenue, Columbus, OH 43210, USA.
| | - Colleen M Cebulla
- Havener Eye Institute, Department of Ophthalmology and Visual Science, The Ohio State University Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, USA.
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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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Williams AL, Eason J, Chawla B, Bohnsack BL. Cyp1b1 Regulates Ocular Fissure Closure Through a Retinoic Acid-Independent Pathway. Invest Ophthalmol Vis Sci 2017; 58:1084-1097. [PMID: 28192799 PMCID: PMC5308778 DOI: 10.1167/iovs.16-20235] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Mutations in the CYP1B1 gene are the most commonly identified genetic causes of primary infantile-onset glaucoma. Despite this disease association, the role of CYP1B1 in eye development and its in vivo substrate remain unknown. In the present study, we used zebrafish to elucidate the mechanism by which cyp1b1 regulates eye development. Methods Zebrafish eye and neural crest development were analyzed using live imaging of transgenic zebrafish embryos, in situ hybridization, immunostaining, TUNEL assay, and methylacrylate sections. Cyp1b1 and retinoic acid (RA) levels were genetically (morpholino oligonucleotide antisense and mRNA) and pharmacologically manipulated to examine gene function. Results Using zebrafish, we observed that cyp1b1 was expressed in a specific spatiotemporal pattern in the ocular fissures of the developing zebrafish retina and regulated fissure patency. Decreased Cyp1b1 resulted in the premature breakdown of laminin in the ventral fissure and altered subsequent neural crest migration into the anterior segment. In contrast, cyp1b1 overexpression inhibited cell survival in the ventral ocular fissure and prevented fissure closure via an RA-independent pathway. Cyp1b1 overexpression also inhibited the ocular expression of vsx2, pax6a, and pax6b and increased the extraocular expression of shha. Importantly, embryos injected with human wild-type but not mutant CYP1B1 mRNA also showed colobomas, demonstrating the evolutionary and functional conservation of gene function between species. Conclusions Cyp1b1 regulation of ocular fissure closure indirectly affects neural crest migration and development through an RA-independent pathway. These studies provide insight into the role of Cyp1b1 in eye development and further elucidate the pathogenesis of primary infantile-onset glaucoma.
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Affiliation(s)
- Antionette L Williams
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Jessica Eason
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Bahaar Chawla
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | - Brenda L Bohnsack
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
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18
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Sun J, Rockowitz S, Xie Q, Ashery-Padan R, Zheng D, Cvekl A. Identification of in vivo DNA-binding mechanisms of Pax6 and reconstruction of Pax6-dependent gene regulatory networks during forebrain and lens development. Nucleic Acids Res 2015; 43:6827-46. [PMID: 26138486 PMCID: PMC4538810 DOI: 10.1093/nar/gkv589] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/23/2015] [Indexed: 01/18/2023] Open
Abstract
The transcription factor Pax6 is comprised of the paired domain (PD) and homeodomain (HD). In the developing forebrain, Pax6 is expressed in ventricular zone precursor cells and in specific subpopulations of neurons; absence of Pax6 results in disrupted cell proliferation and cell fate specification. Pax6 also regulates the entire lens developmental program. To reconstruct Pax6-dependent gene regulatory networks (GRNs), ChIP-seq studies were performed using forebrain and lens chromatin from mice. A total of 3514 (forebrain) and 3723 (lens) Pax6-containing peaks were identified, with ∼70% of them found in both tissues and thereafter called 'common' peaks. Analysis of Pax6-bound peaks identified motifs that closely resemble Pax6-PD, Pax6-PD/HD and Pax6-HD established binding sequences. Mapping of H3K4me1, H3K4me3, H3K27ac, H3K27me3 and RNA polymerase II revealed distinct types of tissue-specific enhancers bound by Pax6. Pax6 directly regulates cortical neurogenesis through activation (e.g. Dmrta1 and Ngn2) and repression (e.g. Ascl1, Fezf2, and Gsx2) of transcription factors. In lens, Pax6 directly regulates cell cycle exit via components of FGF (Fgfr2, Prox1 and Ccnd1) and Wnt (Dkk3, Wnt7a, Lrp6, Bcl9l, and Ccnd1) signaling pathways. Collectively, these studies provide genome-wide analysis of Pax6-dependent GRNs in lens and forebrain and establish novel roles of Pax6 in organogenesis.
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Affiliation(s)
- Jian Sun
- The Departments of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Shira Rockowitz
- The Departments of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Qing Xie
- The Departments of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine and Sagol School of Neuroscience, Tel-Aviv University, 69978 Ramat Aviv, Tel Aviv, Israel
| | - Deyou Zheng
- The Departments of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ales Cvekl
- The Departments of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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19
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β-Catenin inactivation is a pre-requisite for chick retina regeneration. PLoS One 2014; 9:e101748. [PMID: 25003522 PMCID: PMC4086939 DOI: 10.1371/journal.pone.0101748] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 06/11/2014] [Indexed: 11/19/2022] Open
Abstract
In the present study we explored the role of β-catenin in mediating chick retina regeneration. The chick can regenerate its retina by activating stem/progenitor cells present in the ciliary margin (CM) of the eye or via transdifferentiation of the retinal pigmented epithelium (RPE). Both modes require fibroblast growth factor 2 (FGF2). We observed, by immunohistochemistry, dynamic changes of nuclear β-catenin in the CM and RPE after injury (retinectomy). β-catenin nuclear accumulation was transiently lost in cells of the CM in response to injury alone, while the loss of nuclear β-catenin was maintained as long as FGF2 was present. However, nuclear β-catenin positive cells remained in the RPE in response to injury and were BrdU-/p27+, suggesting that nuclear β-catenin prevents those cells from entering the cell cycle. If FGF2 is present, the RPE undergoes dedifferentiation and proliferation concomitant with loss of nuclear β-catenin. Moreover, retinectomy followed by disruption of active β-catenin by using a signaling inhibitor (XAV939) or over-expressing a dominant negative form of Lef-1 induces regeneration from both the CM and RPE in the absence of FGF2. Our results imply that β-catenin protects cells of the CM and RPE from entering the cell cycle in the developing eye, and specifically for the RPE during injury. Thus inactivation of β-catenin is a pre-requisite for chick retina regeneration.
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20
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Ma ZL, Wang G, Cheng X, Chuai M, Kurihara H, Lee KKH, Yang X. Excess caffeine exposure impairs eye development during chick embryogenesis. J Cell Mol Med 2014; 18:1134-43. [PMID: 24636305 PMCID: PMC4508153 DOI: 10.1111/jcmm.12260] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 01/22/2014] [Indexed: 12/17/2022] Open
Abstract
Caffeine has been an integral component of our diet and medicines for centuries. It is now known that over consumption of caffeine has detrimental effects on our health, and also disrupts normal foetal development in pregnant mothers. In this study, we investigated the potential teratogenic effect of caffeine over-exposure on eye development in the early chick embryo. Firstly, we demonstrated that caffeine exposure caused chick embryos to develop asymmetrical microphthalmia and induced the orbital bone to develop abnormally. Secondly, caffeine exposure perturbed Pax6 expression in the retina of the developing eye. In addition, it perturbed the migration of HNK-1+ cranial neural crest cells. Pax6 is an important gene that regulates eye development, so altering the expression of this gene might be the cause for the abnormal eye development. Thirdly, we found that reactive oxygen species (ROS) production was significantly increased in eye tissues following caffeine treatment, and that the addition of anti-oxidant vitamin C could rescue the eyes from developing abnormally in the presence of caffeine. This suggests that excess ROS induced by caffeine is one of the mechanisms involved in the teratogenic alterations observed in the eye during embryogenesis. In sum, our experiments in the chick embryo demonstrated that caffeine is a potential teratogen. It causes asymmetrical microphthalmia to develop by increasing ROS production and perturbs Pax6 expression.
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Affiliation(s)
- Zheng-Lai Ma
- Department of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Institute of Fetal-Preterm Labor Medicine, Medical College of Jinan University, Guangzhou, China
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21
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Klimova L, Kozmik Z. Stage-dependent requirement of neuroretinal Pax6 for lens and retina development. Development 2014; 141:1292-302. [PMID: 24523460 DOI: 10.1242/dev.098822] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The physical contact of optic vesicle with head surface ectoderm is an initial event triggering eye morphogenesis. This interaction leads to lens specification followed by coordinated invagination of the lens placode and optic vesicle, resulting in formation of the lens, retina and retinal pigmented epithelium. Although the role of Pax6 in early lens development has been well documented, its role in optic vesicle neuroepithelium and early retinal progenitors is poorly understood. Here we show that conditional inactivation of Pax6 at distinct time points of mouse neuroretina development has a different impact on early eye morphogenesis. When Pax6 is eliminated in the retina at E10.5 using an mRx-Cre transgene, after a sufficient contact between the optic vesicle and surface ectoderm has occurred, the lens develops normally but the pool of retinal progenitor cells gradually fails to expand. Furthermore, a normal differentiation program is not initiated, leading to almost complete disappearance of the retina after birth. By contrast, when Pax6 was inactivated at the onset of contact between the optic vesicle and surface ectoderm in Pax6(Sey/flox) embryos, expression of lens-specific genes was not initiated and neither the lens nor the retina formed. Our data show that Pax6 in the optic vesicle is important not only for proper retina development, but also for lens formation in a non-cell-autonomous manner.
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Affiliation(s)
- Lucie Klimova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, 14420 Prague 4, Czech Republic
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22
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Huber C, Anand AAP, Mauz M, Künstle P, Hupp W, Hirt B, Wizenmann A. In ovo expression of microRNA in ventral chick midbrain. J Vis Exp 2013:e50024. [PMID: 24084475 DOI: 10.3791/50024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Non-coding RNAs are additional players in regulating gene expression. Targeted in ovo electroporation of specific areas provides a unique tool for spatial and temporal control of ectopic microRNA expression. However, ventral brain structures like ventral midbrain are rather difficult to reach for any manipulations. Here, we demonstrate an efficient way to electroporate miRNA into ventral midbrain using thin platinum electrodes. This method offers a reliable way to transfect specific areas of the midbrain and a useful tool for in vivo studies.
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Affiliation(s)
- Carola Huber
- Department of Experimental Embryology, Institute of Anatomy, University of Tübingen
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23
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Ex vivo electroporation of retinal cells: a novel, high efficiency method for functional studies in primary retinal cultures. Exp Eye Res 2013; 109:40-50. [PMID: 23370269 DOI: 10.1016/j.exer.2013.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/17/2012] [Accepted: 01/19/2013] [Indexed: 11/22/2022]
Abstract
Primary retinal cultures constitute valuable tools not only for basic research on retinal cell development and physiology, but also for the identification of factors or drugs that promote cell survival and differentiation. In order to take full advantage of the benefits of this system it is imperative to develop efficient and reliable techniques for the manipulation of gene expression. However, achieving appropriate transfection efficiencies in these cultures has remained challenging. The purpose of this work was to develop and optimize a technique that would allow the transfection of chick retinal cells with high efficiency and reproducibility for multiple applications. We developed an ex vivo electroporation method applied to dissociated retinal cell cultures that offers a significant improvement over other currently available transfection techniques, increasing efficiency by five-fold. In this method, eyes were enucleated, devoid of RPE, and electroporated with GFP-encoding plasmids using custom-made electrodes. Electroporated retinas were then dissociated into single cells and plated in low density conditions, to be analyzed after 4 days of incubation. Parameters such as voltage and number of electric pulses, as well as plasmid concentration and developmental stage of the animal were optimized for efficiency. The characteristics of the cultures were assessed by morphology and immunocytochemistry, and cell viability was determined by ethidium homodimer staining. Cell imaging and counting was performed using an automated high-throughput system. This procedure resulted in transfection efficiencies in the order of 22-25% of cultured cells, encompassing both photoreceptors and non-photoreceptor neurons, and without affecting normal cell survival and differentiation. Finally, the feasibility of the technique for cell-autonomous studies of gene function in a biologically relevant context was tested by carrying out gain and loss-of-function experiments for the transcription factor PAX6. Electroporation of a plasmid construct expressing PAX6 resulted in a marked upregulation in the expression levels of this protein that could be measured in the whole culture as well as cell-intrinsically. This was accompanied by a significant decrease in the percentage of cells differentiating as photoreceptors among the transfected population. Conversely, electroporation of an RNAi construct targeting PAX6 resulted in a significant decrease in the levels of this protein, with a concomitant increase in the proportion of photoreceptors. Taken together these results provide strong proof-of-principle of the suitability of this technique for genetic studies in retinal cultures. The combination of the high transfection efficiency obtained by this method with automated high-throughput cell analysis supplies the scientific community with a powerful system for performing functional studies in a cell-autonomous manner.
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24
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Han W, Han YP, Wang ZR. Apoptosis and differentiation in presumptive neural retina and presumptive retinal pigmented epithelium during early eye development in toad, Bufo raddei strauch. Russ J Dev Biol 2012. [DOI: 10.1134/s1062360412060033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Sousounis K, Tsonis PA. Patterns of gene expression in microarrays and expressed sequence tags from normal and cataractous lenses. Hum Genomics 2012; 6:14. [PMID: 23244575 PMCID: PMC3563465 DOI: 10.1186/1479-7364-6-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 11/30/2022] Open
Abstract
In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts.
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Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, OH 45469-2320, USA
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26
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Vergara MN, Canto-Soler MV. Rediscovering the chick embryo as a model to study retinal development. Neural Dev 2012; 7:22. [PMID: 22738172 PMCID: PMC3541172 DOI: 10.1186/1749-8104-7-22] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 05/22/2012] [Indexed: 01/20/2023] Open
Abstract
The embryonic chick occupies a privileged place among animal models used in developmental studies. Its rapid development and accessibility for visualization and experimental manipulation are just some of the characteristics that have made it a vertebrate model of choice for more than two millennia. Until a few years ago, the inability to perform genetic manipulations constituted a major drawback of this system. However, the completion of the chicken genome project and the development of techniques to manipulate gene expression have allowed this classic animal model to enter the molecular age. Such techniques, combined with the embryological manipulations that this system is well known for, provide a unique toolkit to study the genetic basis of neural development. A major advantage of these approaches is that they permit targeted gene misexpression with extremely high spatiotemporal resolution and over a large range of developmental stages, allowing functional analysis at a level, speed and ease that is difficult to achieve in other systems. This article provides a general overview of the chick as a developmental model focusing more specifically on its application to the study of eye development. Special emphasis is given to the state of the art of the techniques that have made gene gain- and loss-of-function studies in this model a reality. In addition, we discuss some methodological considerations derived from our own experience that we believe will be beneficial to researchers working with this system.
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Affiliation(s)
- M Natalia Vergara
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Smith Building 3023, 400 N Broadway, Baltimore, MD 21287-9257, USA
| | - M Valeria Canto-Soler
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Smith Building 3023, 400 N Broadway, Baltimore, MD 21287-9257, USA
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27
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Abstract
Gene recruitment played a critical role in metazoan evolution. Yet, there is no consensus on whether it is an accidental event or a result of an inherent "gene recruiting" mechanism. The prevailing opinion among biologists is that gene recruitment results from random changes in genes or their regulatory regions, but the supporting evidence is poor and controversial. Herein, I present a mechanism in which gene recruitment is a neurally determined event, an adaptive response to changes in environmental conditions. In support of the hypothesis, I present evidence on the manipulative expression of genes in the central nervous system, as well as neurally determined examples of gene recruitment in transgenerational developmental plasticity and in evolution of metazoans.
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McNally MM, Wahlin KJ, Canto-Soler MV. Endogenous expression of ASLV viral proteins in specific pathogen free chicken embryos: relevance for the developmental biology research field. BMC DEVELOPMENTAL BIOLOGY 2010; 10:106. [PMID: 20955591 PMCID: PMC2973938 DOI: 10.1186/1471-213x-10-106] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Accepted: 10/18/2010] [Indexed: 12/05/2022]
Abstract
Background The use of Specific Pathogen Free (SPF) eggs in combination with RCAS retrovirus, a member of the Avian Sarcoma-Leukosis Virus (ASLV) family, is of standard practice to study gene function and development. SPF eggs are certified free of infection by specific pathogen viruses of either exogenous or endogenous origin, including those belonging to the ASLV family. Based on this, SPF embryos are considered to be free of ASLV viral protein expression, and consequently in developmental research studies RCAS infected cells are routinely identified by immunohistochemistry against the ASLV viral proteins p19 and p27. Contrary to this generally accepted notion, observations in our laboratory suggested that certified SPF chicken embryos may endogenously express ASLV viral proteins p19 and p27. Since these observations may have significant implications for the developmental research field we further investigated this possibility. Results We demonstrate that certified SPF chicken embryos have transcriptionally active endogenous ASLV loci (ev loci) capable of expressing ASLV viral proteins, such as p19 and p27, even when those loci are not capable of producing viral particles. We also show that the extent of viral protein expression in embryonic tissues varies not only among flocks but also between embryos of the same flock. In addition, our genetic screening revealed significant heterogeneity in ev loci composition even among embryos of the same flock. Conclusions These observations have critical implications for the developmental biology research field, since they strongly suggest that the current standard methodology used in experimental studies using the chick embryo and RCAS vectors may lead to inaccurate interpretation of results. Retrospectively, our observations suggest that studies in which infected cells have been identified simply by pan-ASLV viral protein expression may need to be considered with caution. For future studies, they point to a need for careful selection and screening of the chick SPF lines to be used in combination with RCAS constructs, as well as the methodology utilized for qualitative analysis of experimental results. A series of practical guidelines to ensure research quality animals and accuracy of the interpretation of results is recommended and discussed.
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Affiliation(s)
- Minda M McNally
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, 400 N Broadway, Baltimore, MD, USA
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29
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Shin SK, O'Brien KMB. Progenitor cells of the rod-free area centralis originate in the anterior dorsal optic vesicle. BMC DEVELOPMENTAL BIOLOGY 2009; 9:57. [PMID: 19939282 PMCID: PMC3224689 DOI: 10.1186/1471-213x-9-57] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 11/25/2009] [Indexed: 01/12/2023]
Abstract
Background Nervous system development is dependent on early regional specification to create functionally distinct tissues within an initially undifferentiated zone. Within the retina, photoreceptors are topographically organized with rod free area centrales faithfully generated at the centre of gaze. How does the developing eye regulate this placement? Conventional wisdom indicates that the distal tip of the growing optic vesicle (OV) gives rise to the area centralis/fovea. Ectopic expression and ablation studies do not fully support this view, creating a controversy as to the origin of this region. In this study, the lineage of cells in the chicken OV was traced using DiI. The location of labelled cells was mapped onto the retina in relation to the rod-free zone at embryonic (E) 7 and E17.5. The ability to regenerate a rod free area after OV ablation was determined in conjunction with lineage tracing. Results Anterior OV gave rise to cells in nasal retina and posterior OV became temporal retina. The OV distal tip gave rise to cells above the optic nerve head. A dorsal and anterior region of the OV correlated with cells in the developing rod free area centralis. Only ablations including the dorsal anterior region gave rise to a retina lacking a rod free zone. DiI application after ablation indicated that cells movements were greater along the anterior/posterior axis compared with the dorsal/ventral axis. Conclusion Our data support the idea that the chicken rod free area centralis originates from cells located near, but not at the distal tip of the developing OV. Therefore, the hypothesis that the area centralis is derived from cells at the distal tip of the OV is not supported; rather, a region anterior and dorsal to the distal tip gives rise to the rod free region. When compared with other studies of retinal development, our results are supported on molecular, morphological and functional levels. Our data will lead to a better understanding of the mechanisms underlying the topographic organization of the retina, the origin of the rod free zone, and the general issue of compartmentalization of neural tissue before any indication of morphological differentiation.
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Affiliation(s)
- Sae Kyung Shin
- Optometry and Vision Science, The University of Auckland, Auckland, NZ.
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30
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Relationship of Pax6 activity levels to the extent of eye development in the mouse, Mus musculus. Genetics 2008; 179:1345-55. [PMID: 18562673 DOI: 10.1534/genetics.108.088591] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In this study we extend the mouse Pax6 mutant allelic series to include a homozygous and hemizygous viable hypomorph allele. The Pax6(132-14Neu) allele is a Phe272Ile missense mutation within the third helix of the homeodomain. The mutant Pax6 homeodomain shows greatly reduced binding activity to the P3 DNA binding target. Glucagon-promoter activation by the entire mutant Pax6 product of a reporter gene driven by the G1 paired and homeodomain DNA binding target was slightly increased. We constructed mutant Pax6 genotypes such that Pax6 activity ranged between 100 and 0% and show that the extent of eye development is progressively reduced as Pax6 activity decreased. Two apparent thresholds identify three groups in which the extent of eye development abruptly shifted from complete eye at the highest levels of Pax6 to a rudimentary eye at intermediate levels of Pax6 to very early termination of eye development at the lowest levels of Pax6. Of the two Pax6-positive regions that participate in eye development, the surface ectoderm, which develops into the lens vesicle and the cornea, is more sensitive to reduced levels of Pax6 activity than the optic vesicle, which develops into the inner and outer retinal layers.
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31
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Canto-Soler MV, Huang H, Romero MS, Adler R. Transcription factors CTCF and Pax6 are segregated to different cell types during retinal cell differentiation. Dev Dyn 2008; 237:758-67. [PMID: 18224715 DOI: 10.1002/dvdy.21420] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We have hypothesized that the transcription factor CTCF may influence retinal cell differentiation by controlling Pax6 expression, because (1) CTCF has been shown to repress Pax6 expression in some tissues, and (2) Pax6 blocks the differentiation of retinal progenitor cells as photoreceptors and promotes their differentiation as nonphotoreceptor neurons. Our results show that, as predicted by this hypothesis, CTCF and Pax6 become segregated to different retinal cell types. The factors are initially coexpressed in the undifferentiated neuroepithelium, but already at that time they show complementary periphery-to-fundus gradients of distribution. As the retina laminates, Pax6 becomes restricted to ganglion and amacrine cells, and CTCF to the bipolar/Muller cell layer and the outer nuclear layer. Polymerase chain reaction analysis of laser capture microdissection samples and dissociated cells showed that both immature and differentiated photoreceptors are CTCF (+)/ Pax6 (-). Functional studies are now under way to further analyze the role of CTCF in retinal cell differentiation.
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Affiliation(s)
- M Valeria Canto-Soler
- The Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9257, USA.
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32
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Sehgal R, Karcavich R, Carlson S, Belecky-Adams TL. Ectopic Pax2 expression in chick ventral optic cup phenocopies loss of Pax2 expression. Dev Biol 2008; 319:23-33. [PMID: 18485342 DOI: 10.1016/j.ydbio.2008.03.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 03/28/2008] [Accepted: 03/28/2008] [Indexed: 11/29/2022]
Abstract
Pax2 is essential for the development of the urogenital system, neural tube, otic vesicle, optic cup and optic tract [Dressler, G.R., Deutsch, U., et al., 1990. PAX2, a new murine paired-box-containing gene and its expression in the developing excretory system. Development 109 (4), 787-795; Nornes, H.O., Dressler, G.R., et al., 1990. Spatially and temporally restricted expression of Pax2 during murine neurogenesis. Development 109 (4), 797-809; Eccles, M.R., Wallis, L.J., et al., 1992. Expression of the PAX2 gene in human fetal kidney and Wilms' tumor. Cell Growth Differ 3 (5), 279-289]. Within the visual system, a loss-of-function leads to lack of choroid fissure closure (known as a coloboma), a loss of optic nerve astrocytes, and anomalous axonal pathfinding at the optic chiasm [Favor, J., Sandulache, R., et al., 1996. The mouse Pax2(1Neu) mutation is identical to a human PAX2 mutation in a family with renal-coloboma syndrome and results in developmental defects of the brain, ear, eye, and kidney. Proc. Natl. Acad. Sci. U. S. A. 93 (24), 13870-13875; Torres, M., Gomez-Pardo, E., et al., 1996. Pax2 contributes to inner ear patterning and optic nerve trajectory. Development 122 (11), 3381-3391]. This study is directed at determining the effects of ectopic Pax2 expression in the chick ventral optic cup past the normal developmental period when Pax2 is found. In ovo electroporation of Pax2 into the chick ventral optic cup results in the formation of colobomas, a condition typically associated with a loss of Pax2 expression. While the overexpression of Pax2 appears to phenocopy a loss of Pax2, the mechanism of the failure of choroid fissure closure is associated with a cell fate switch from ventral retina and retinal pigmented epithelium (RPE) to an astrocyte fate. Further, ectopic expression of Pax2 in RPE appears to have non-cell autonomous effects on adjacent RPE, creating an ectopic neural retina in place of the RPE.
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Affiliation(s)
- Rachna Sehgal
- Department of Biology and Center for Regenerative Biology and Medicine, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
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Adler R. Curing blindness with stem cells: hope, reality, and challenges. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 613:3-20. [PMID: 18188924 DOI: 10.1007/978-0-387-74904-4_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Ruben Adler
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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34
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Van Raay TJ, Lassiter RT, Stark MR. Electroporation strategies for genetic manipulation and cell labeling. Methods Mol Biol 2008; 438:305-317. [PMID: 18369766 DOI: 10.1007/978-1-59745-133-8_23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Electroporation has emerged as an effective method for cell labeling and manipulation of gene expression. In the past decade, electroporation applications have expanded to include in vivo chick, mouse, Xenopus, and zebrafish techniques, along with numerous in vitro strategies for cell and tissue culture. We focus on applications relevant to neural stem cell research, providing detailed protocols for in ovo chick electroporation and in vitro targeting of neuroepithelial precursor cells. Electroporation descriptions and related figures identify the tools and reagents needed to carry out targeting of the neuroepithelium. Various applications of the electroporation technique in neural stem cell research are highlighted, along with corresponding publications.
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Affiliation(s)
- Terence J Van Raay
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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Reza HM, Nishi H, Kataoka K, Takahashi Y, Yasuda K. L-Maf regulates p27kip1 expression during chick lens fiber differentiation. Differentiation 2007; 75:737-44. [PMID: 17428264 DOI: 10.1111/j.1432-0436.2007.00171.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Organ formation requires spatio-temporal proliferation and differentiation of precursor cells. During lens development, placodal cells in the posterior lens vesicle exit from the cell cycle and enter into the process of differentiation. Cyclin-dependent kinase inhibitors play critical roles in cell cycle exit and promote differentiation in several tissues. We have found that p27kip1 is expressed in the posterior lens cells that undergo differentiation to form the differentiated fiber cells. The transcription factor L-Maf is expressed in these cells earlier than p27kip1. From in ovo gain- or loss-of-function experiments, we have found that L-Maf can, respectively, induce or inhibit the expression of p27kip1 in lens cells. Promoter assays using the 5' upstream sequences of the human p27kip1 gene indicate that L-Maf can activate p27kip1 transcription through the basal regulatory region. We suggest that L-Maf regulates cell cycle exit of the posterior lens cells by activating p27kip1, and thus directs fiber cell differentiation during lens formation in chick.
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Affiliation(s)
- Hasan Mahmud Reza
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
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36
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Reza HM, Takahashi Y, Yasuda K. Stage-dependent expression of Pax6 in optic vesicle/cup regulates patterning genes through signaling molecules. Differentiation 2007; 75:726-36. [PMID: 17381541 DOI: 10.1111/j.1432-0436.2007.00168.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dorso-ventral and proximo-distal axis formation of the optic cup is apparent from early stages of development. Pax6 is initially detectable in the optic vesicle and later shows a distal-high and proximal-low gradient of expression in the retina. To determine the early role of Pax6 in pattern formation of the optic cup, we expressed Pax6 ectopically in the optic vesicle of stages 9-10 chick embryos by in ovo electroporation, which resulted in a small eye-like phenotype. The signaling molecule fibroblast growth factor (FGF)8, which appears to be restricted to the central retina, was increased, whereas bone morphogenetic protein (BMP)4 and Tbx5, two dorsal markers, were down-regulated in Pax6-electroporated eye. Pax6 overexpression also decreased the expression of the ventral marker Vax. Electroporation with a dominant-negative form of Pax6 resulted in a decrease in FGF8 expression, but BMP4 expression was unaffected initially while it was diminished later. Our data suggest a new role for Pax6 in regulating FGF8 and BMP4 expression during pattern formation of the optic cup, and that a Pax6-regulated balance between FGF8 and BMP4 is critical for retinogenesis.
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Affiliation(s)
- Hasan Mahmud Reza
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan
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37
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Adler R, Raymond PA. Have we achieved a unified model of photoreceptor cell fate specification in vertebrates? Brain Res 2007; 1192:134-50. [PMID: 17466954 PMCID: PMC2288638 DOI: 10.1016/j.brainres.2007.03.044] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2007] [Revised: 03/08/2007] [Accepted: 03/16/2007] [Indexed: 12/01/2022]
Abstract
How does a retinal progenitor choose to differentiate as a rod or a cone and, if it becomes a cone, which one of their different subtypes? The mechanisms of photoreceptor cell fate specification and differentiation have been extensively investigated in a variety of animal model systems, including human and non-human primates, rodents (mice and rats), chickens, frogs (Xenopus) and fish. It appears timely to discuss whether it is possible to synthesize the resulting information into a unified model applicable to all vertebrates. In this review we focus on several widely used experimental animal model systems to highlight differences in photoreceptor properties among species, the diversity of developmental strategies and solutions that vertebrates use to create retinas with photoreceptors that are adapted to the visual needs of their species, and the limitations of the methods currently available for the investigation of photoreceptor cell fate specification. Based on these considerations, we conclude that we are not yet ready to construct a unified model of photoreceptor cell fate specification in the developing vertebrate retina.
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Affiliation(s)
| | - Pamela A. Raymond
- Department of Molecular, Cellular and Developmental Biology, University of Michigan
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Abstract
The recent identification of a mutation in Foxe3 that causes congenital primary aphakia in humans marks an important milestone. Congenital primary aphakia is a rare developmental disease in which the lens does not form. Previously, Foxe3 had been shown to play a crucial role in vertebrate lens formation and this gene is one of the earliest integrators of several signaling pathways that cooperate to form a lens. In this review, we highlight recent advances that have led to a better understanding of the developmental processes and gene regulatory networks involved in lens development and disease.
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Affiliation(s)
- Olga Medina-Martinez
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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39
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Adler R, Canto-Soler MV. Molecular mechanisms of optic vesicle development: complexities, ambiguities and controversies. Dev Biol 2007; 305:1-13. [PMID: 17335797 PMCID: PMC1927083 DOI: 10.1016/j.ydbio.2007.01.045] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 01/26/2007] [Accepted: 01/30/2007] [Indexed: 12/31/2022]
Abstract
Optic vesicle formation, transformation into an optic cup and integration with neighboring tissues are essential for normal eye formation, and involve the coordinated occurrence of complex cellular and molecular events. Perhaps not surprisingly, these complex phenomena have provided fertile ground for controversial and even contradictory results and conclusions. After presenting an overview of current knowledge of optic vesicle development, we will address conceptual and methodological issues that complicate research in this field. This will be done through a review of the pertinent literature, as well as by drawing on our own experience, gathered through recent studies of both intra- and extra-cellular regulation of optic vesicle development and patterning. Finally, and without attempting to be exhaustive, we will point out some important aspects of optic vesicle development that have not yet received enough attention.
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Affiliation(s)
- Ruben Adler
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21287-9257, USA.
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