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De Magalhães CG, Cvekl A, Jaeger RG, Yan CYI. Lens placode modulates extracellular matrix formation during early eye development. Differentiation 2024; 138:100792. [PMID: 38935992 PMCID: PMC11247415 DOI: 10.1016/j.diff.2024.100792] [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: 03/26/2024] [Revised: 06/13/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024]
Abstract
The role extracellular matrix (ECM) in multiple events of morphogenesis has been well described, little is known about its specific role in early eye development. One of the first morphogenic events in lens development is placodal thickening, which converts the presumptive lens ectoderm from cuboidal to pseudostratified epithelium. This process occurs in the anterior pre-placodal ectoderm when the optic vesicle approaches the cephalic ectoderm and is regulated by transcription factor Pax6 and secreted BMP4. Since cells and ECM have a dynamic relationship of interdependence and modulation, we hypothesized that the ECM evolves with cell shape changes during lens placode formation. This study investigates changes in optic ECM including both protein distribution deposition, extracellular gelatinase activity and gene expression patterns during early optic development using chicken and mouse models. In particular, the expression of Timp2, a metalloprotease inhibitor, corresponds with a decrease in gelatinase activity within the optic ECM. Furthermore, we demonstrate that optic ECM remodeling depends on BMP signaling in the placode. Together, our findings suggest that the lens placode plays an active role in remodeling the optic ECM during early eye development.
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Affiliation(s)
- Cecília G De Magalhães
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, 05508-900, Brazil
| | - Ales Cvekl
- Department of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ruy G Jaeger
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, 05508-900, Brazil
| | - C Y Irene Yan
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, 05508-900, Brazil.
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2
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De Magalhães CG, Cvekl A, Jaeger RG, Yan CYI. Lens Placode Modulates Extracellular Matrix Formation During Early Eye Development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.30.569417. [PMID: 38076974 PMCID: PMC10705410 DOI: 10.1101/2023.11.30.569417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
The role extracellular matrix (ECM) in multiple events of morphogenesis has been well described, little is known about its specific role in early eye development. One of the first morphogenic events in lens development is placodal thickening, which converts the presumptive lens ectoderm from cuboidal to pseudostratified epithelium. This process occurs in the anterior pre-placodal ectoderm when the optic vesicle approaches the cephalic ectoderm. Since cells and ECM have a dynamic relationship of interdependence and modulation, we hypothesized that the ECM evolves with cell shape changes during lens placode formation. This study investigates changes in optic ECM including both protein distribution deposition, extracellular gelatinase activity and gene expression patterns during early optic development using chicken and mouse models. In particular, the expression of Timp2 , a metalloprotease inhibitor, corresponds with a decrease in gelatinase activity within the optic ECM. Furthermore, we demonstrate that optic ECM remodeling depends on BMP signaling in the placode. Together, our findings suggest that the lens placode plays an active role in remodeling the optic ECM during early eye development.
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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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Gerhart J, George-Weinstein M. Myo/Nog Cells: The Jekylls and Hydes of the Lens. Cells 2023; 12:1725. [PMID: 37443759 PMCID: PMC10340492 DOI: 10.3390/cells12131725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/21/2023] [Accepted: 06/24/2023] [Indexed: 07/15/2023] Open
Abstract
Herein, we review a unique and versatile lineage composed of Myo/Nog cells that may be beneficial or detrimental depending on their environment and nature of the pathological stimuli they are exposed to. While we will focus on the lens, related Myo/Nog cell behaviors and functions in other tissues are integrated into the narrative of our research that spans over three decades, examines multiple species and progresses from early stages of embryonic development to aging adults. Myo/Nog cells were discovered in the embryonic epiblast by their co-expression of the skeletal muscle-specific transcription factor MyoD, the bone morphogenetic protein inhibitor Noggin and brain-specific angiogenesis inhibitor 1. They were tracked from the epiblast into the developing lens, revealing heterogeneity of cell types within this structure. Depletion of Myo/Nog cells in the epiblast results in eye malformations arising from the absence of Noggin. In the adult lens, Myo/Nog cells are the source of myofibroblasts whose contractions produce wrinkles in the capsule. Eliminating this population within the rabbit lens during cataract surgery reduces posterior capsule opacification to below clinically significant levels. Parallels are drawn between the therapeutic potential of targeting Myo/Nog cells to prevent fibrotic disease in the lens and other ocular tissues.
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Wishart TFL, Lovicu FJ. Spatiotemporal Localisation of Heparan Sulphate Proteoglycans throughout Mouse Lens Morphogenesis. Cells 2023; 12:1364. [PMID: 37408198 DOI: 10.3390/cells12101364] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 07/07/2023] Open
Abstract
Heparan sulphate proteoglycans (HSPGs) consist of a core protein decorated with sulphated HS-glycosaminoglycan (GAG) chains. These negatively charged HS-GAG chains rely on the activity of PAPSS synthesising enzymes for their sulfation, which allows them to bind to and regulate the activity of many positively charged HS-binding proteins. HSPGs are found on the surfaces of cells and in the pericellular matrix, where they interact with various components of the cell microenvironment, including growth factors. By binding to and regulating ocular morphogens and growth factors, HSPGs are positioned to orchestrate growth factor-mediated signalling events that are essential for lens epithelial cell proliferation, migration, and lens fibre differentiation. Previous studies have shown that HS sulfation is essential for lens development. Moreover, each of the full-time HSPGs, differentiated by thirteen different core proteins, are differentially localised in a cell-type specific manner with regional differences in the postnatal rat lens. Here, the same thirteen HSPG-associated GAGs and core proteins as well as PAPSS2, are shown to be differentially regulated throughout murine lens development in a spatiotemporal manner. These findings suggest that HS-GAG sulfation is essential for growth factor-induced cellular processes during embryogenesis, and the unique and divergent localisation of different lens HSPG core proteins indicates that different HSPGs likely play specialized roles during lens induction and morphogenesis.
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Affiliation(s)
- Tayler F L Wishart
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Frank J Lovicu
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Save Sight Institute, The University of Sydney, Sydney, NSW 2006, Australia
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Disatham J, Brennan L, Cvekl A, Kantorow M. Multiomics Analysis Reveals Novel Genetic Determinants for Lens Differentiation, Structure, and Transparency. Biomolecules 2023; 13:693. [PMID: 37189439 PMCID: PMC10136076 DOI: 10.3390/biom13040693] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/13/2023] [Accepted: 04/16/2023] [Indexed: 05/17/2023] Open
Abstract
Recent advances in next-generation sequencing and data analysis have provided new gateways for identification of novel genome-wide genetic determinants governing tissue development and disease. These advances have revolutionized our understanding of cellular differentiation, homeostasis, and specialized function in multiple tissues. Bioinformatic and functional analysis of these genetic determinants and the pathways they regulate have provided a novel basis for the design of functional experiments to answer a wide range of long-sought biological questions. A well-characterized model for the application of these emerging technologies is the development and differentiation of the ocular lens and how individual pathways regulate lens morphogenesis, gene expression, transparency, and refraction. Recent applications of next-generation sequencing analysis on well-characterized chicken and mouse lens differentiation models using a variety of omics techniques including RNA-seq, ATAC-seq, whole-genome bisulfite sequencing (WGBS), chip-seq, and CUT&RUN have revealed a wide range of essential biological pathways and chromatin features governing lens structure and function. Multiomics integration of these data has established new gene functions and cellular processes essential for lens formation, homeostasis, and transparency including the identification of novel transcription control pathways, autophagy remodeling pathways, and signal transduction pathways, among others. This review summarizes recent omics technologies applied to the lens, methods for integrating multiomics data, and how these recent technologies have advanced our understanding ocular biology and function. The approach and analysis are relevant to identifying the features and functional requirements of more complex tissues and disease states.
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Affiliation(s)
- Joshua Disatham
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA; (J.D.); (L.B.)
| | - Lisa Brennan
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA; (J.D.); (L.B.)
| | - Ales Cvekl
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| | - Marc Kantorow
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA; (J.D.); (L.B.)
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Wishart TFL, Lovicu FJ. Heparan sulfate proteoglycans (HSPGs) of the ocular lens. Prog Retin Eye Res 2023; 93:101118. [PMID: 36068128 DOI: 10.1016/j.preteyeres.2022.101118] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022]
Abstract
Heparan sulfate proteoglycans (HSPGs) reside in most cells; on their surface, in the pericellular milieu and/or extracellular matrix. In the eye, HSPGs can orchestrate the activity of key signalling molecules found in the ocular environment that promote its development and homeostasis. To date, our understanding of the specific roles played by individual HSPG family members, and the heterogeneity of their associated sulfated HS chains, is in its infancy. The crystalline lens is a relatively simple and well characterised ocular tissue that provides an ideal stage to showcase and model the expression and unique roles of individual HSPGs. Individual HSPG core proteins are differentially localised to eye tissues in a temporal and spatial developmental- and cell-type specific manner, and their loss or functional disruption results in unique phenotypic outcomes for the lens, and other ocular tissues. More recent work has found that different HS sulfation enzymes are also presented in a cell- and tissue-specific manner, and that disruption of these different sulfation patterns affects specific HS-protein interactions. Not surprisingly, these sulfated HS chains have also been reported to be required for lens and eye development, with dysregulation of HS chain structure and function leading to pathogenesis and eye-related phenotypes. In the lens, HSPGs undergo significant and specific changes in expression and function that can drive pathology, or in some cases, promote tissue repair. As master signalling regulators, HSPGs may one day serve as valuable biomarkers, and even as putative targets for the development of novel therapeutics, not only for the eye but for many other systemic pathologies.
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Affiliation(s)
- Tayler F L Wishart
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, NSW, Australia.
| | - Frank J Lovicu
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, NSW, Australia; Save Sight Institute, The University of Sydney, NSW, Australia.
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Cvekl A, Camerino MJ. Generation of Lens Progenitor Cells and Lentoid Bodies from Pluripotent Stem Cells: Novel Tools for Human Lens Development and Ocular Disease Etiology. Cells 2022; 11:cells11213516. [PMID: 36359912 PMCID: PMC9658148 DOI: 10.3390/cells11213516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
In vitro differentiation of human pluripotent stem cells (hPSCs) into specialized tissues and organs represents a powerful approach to gain insight into those cellular and molecular mechanisms regulating human development. Although normal embryonic eye development is a complex process, generation of ocular organoids and specific ocular tissues from pluripotent stem cells has provided invaluable insights into the formation of lineage-committed progenitor cell populations, signal transduction pathways, and self-organization principles. This review provides a comprehensive summary of recent advances in generation of adenohypophyseal, olfactory, and lens placodes, lens progenitor cells and three-dimensional (3D) primitive lenses, "lentoid bodies", and "micro-lenses". These cells are produced alone or "community-grown" with other ocular tissues. Lentoid bodies/micro-lenses generated from human patients carrying mutations in crystallin genes demonstrate proof-of-principle that these cells are suitable for mechanistic studies of cataractogenesis. Taken together, current and emerging advanced in vitro differentiation methods pave the road to understand molecular mechanisms of cataract formation caused by the entire spectrum of mutations in DNA-binding regulatory genes, such as PAX6, SOX2, FOXE3, MAF, PITX3, and HSF4, individual crystallins, and other genes such as BFSP1, BFSP2, EPHA2, GJA3, GJA8, LIM2, MIP, and TDRD7 represented in human cataract patients.
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Affiliation(s)
- Aleš Cvekl
- Departments Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Correspondence: ; Tel.: +1-718-430-3217; Fax: +1-718-430-8778
| | - Michael John Camerino
- Departments Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Murugan S, Cheng C. Roles of Eph-Ephrin Signaling in the Eye Lens Cataractogenesis, Biomechanics, and Homeostasis. Front Cell Dev Biol 2022; 10:852236. [PMID: 35295853 PMCID: PMC8918484 DOI: 10.3389/fcell.2022.852236] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/04/2022] [Indexed: 01/26/2023] Open
Abstract
The eye lens is responsible for fine focusing of light onto the retina, and its function relies on tissue transparency and biomechanical properties. Recent studies have demonstrated the importance of Eph-ephrin signaling for the maintenance of life-long lens homeostasis. The binding of Eph receptor tyrosine kinases to ephrin ligands leads to a bidirectional signaling pathway that controls many cellular processes. In particular, dysfunction of the receptor EphA2 or the ligand ephrin-A5 lead to a variety of congenital and age-related cataracts, defined as any opacity in the lens, in human patients. In addition, a wealth of animal studies reveal the unique and overlapping functions of EphA2 and ephrin-A5 in lens cell shape, cell organization and patterning, and overall tissue optical and biomechanical properties. Significant differences in lens phenotypes of mouse models with disrupted EphA2 or ephrin-A5 signaling indicate that genetic modifiers likely affect cataract phenotypes and progression, suggesting a possible reason for the variability of human cataracts due to Eph-ephrin dysfunction. This review summarizes the roles of EphA2 and ephrin-A5 in the lens and suggests future avenues of study.
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Shu DY, Lovicu FJ. Insights into Bone Morphogenetic Protein-(BMP-) Signaling in Ocular Lens Biology and Pathology. Cells 2021; 10:cells10102604. [PMID: 34685584 PMCID: PMC8533954 DOI: 10.3390/cells10102604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 01/23/2023] Open
Abstract
Bone morphogenetic proteins (BMPs) are a diverse class of growth factors that belong to the transforming growth factor-beta (TGFβ) superfamily. Although originally discovered to possess osteogenic properties, BMPs have since been identified as critical regulators of many biological processes, including cell-fate determination, cell proliferation, differentiation and morphogenesis, throughout the body. In the ocular lens, BMPs are important in orchestrating fundamental developmental processes such as induction of lens morphogenesis, and specialized differentiation of its fiber cells. Moreover, BMPs have been reported to facilitate regeneration of the lens, as well as abrogate pathological processes such as TGFβ-induced epithelial-mesenchymal transition (EMT) and apoptosis. In this review, we summarize recent insights in this topic and discuss the complexities of BMP-signaling including the role of individual BMP ligands, receptors, extracellular antagonists and cross-talk between canonical and non-canonical BMP-signaling cascades in the lens. By understanding the molecular mechanisms underlying BMP activity, we can advance their potential therapeutic role in cataract prevention and lens regeneration.
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Affiliation(s)
- Daisy Y. Shu
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
| | - Frank J. Lovicu
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia
- Correspondence: ; Tel.: +61-2-9351-5170
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11
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Valensi M, Goldman G, Marchant D, Van Den Berghe L, Jonet L, Daruich A, Robert MP, Krejci E, Klein C, Mascarelli F, Versaux-Botteri C, Moulin A, Putterman M, Guimiot F, Molina T, Terris B, Brémond-Gignac D, Behar-Cohen F, Abitbol MM. Sostdc1 is expressed in all major compartments of developing and adult mammalian eyes. Graefes Arch Clin Exp Ophthalmol 2019; 257:2401-2427. [PMID: 31529323 DOI: 10.1007/s00417-019-04462-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/20/2019] [Accepted: 09/04/2019] [Indexed: 01/16/2023] Open
Abstract
PURPOSE This study was conducted in order to study Sostdc1 expression in rat and human developing and adult eyes. METHODS Using the yeast signal sequence trap screening method, we identified the Sostdc1 cDNA encoding a protein secreted by the adult rat retinal pigment epithelium. We determined by in situ hybridization, RT-PCR, immunohistochemistry, and western blot analysis Sostdc1 gene and protein expression in developing and postnatal rat ocular tissue sections. We also investigated Sostdc1 immunohistolocalization in developing and adult human ocular tissues. RESULTS We demonstrated a prominent Sostdc1 gene expression in the developing rat central nervous system (CNS) and eyes at early developmental stages from E10.5 days postconception (dpc) to E13 dpc. Specific Sostdc1 immunostaining was also detected in most adult cells of rat ocular tissue sections. We also identified the rat ocular embryonic compartments characterized by a specific Sostdc1 immunohistostaining and specific Pax6, Sox2, Otx2, and Vsx2 immunohistostaining from embryonic stages E10.5 to E13 dpc. Furthermore, we determined the localization of SOSTDC1 immunoreactivity in ocular tissue sections of developing and adult human eyes. Indeed, we detected SOSTDC1 immunostaining in developing and adult human retinal pigment epithelium (RPE) and neural retina (NR) as well as in several developing and adult human ocular compartments, including the walls of choroidal and scleral vessels. Of utmost importance, we observed a strong SOSTDC1 expression in a pathological ocular specimen of type 2 Peters' anomaly complicated by retinal neovascularization as well in the walls ofother pathological extra-ocular vessels. CONCLUSION: As rat Sostdc1 and human SOSTDC1 are dual antagonists of the Wnt/β-catenin and BMP signaling pathways, these results underscore the potential crucial roles of these pathways and their antagonists, such as Sostdc1 and SOSTDC1, in developing and adult mammalian normal eyes as well as in syndromic and nonsyndromic congenital eye diseases.
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Affiliation(s)
- Maud Valensi
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Gabrielle Goldman
- APHP, Service de Pathologie de L'Hôpital Cochin-Hôtel-Dieu, Université Paris Descartes, 27 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Dominique Marchant
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- Sorbonne Paris Cité, UFR SMBH, Laboratoire Hypoxie et poumons, Université Paris 13, EA 2363, 93017, Bobigny, France
| | - Loïc Van Den Berghe
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- Inserm UMR 1037, CRCT (Cancer Research Center of Toulouse), 31037, Toulouse, France
| | - Laurent Jonet
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Alejandra Daruich
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France
| | - Matthieu P Robert
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France
- COGnition and Action Group, UMR 8257, CNRS, Université Paris Descartes, Paris, France
| | - Eric Krejci
- COGnition and Action Group, UMR 8257, CNRS, Université Paris Descartes, Paris, France
| | - Christophe Klein
- Centre d'Imagerie Cellulaire et de Cytométrie (CICC), Centre de Recherche des Cordeliers (CRC), Université Pierre et Marie Curie - Paris 6, Université Paris Descartes - Paris 5, UMR_S 1138, 75006, Paris, France
| | - Frédéric Mascarelli
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Claudine Versaux-Botteri
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Alexandre Moulin
- Département de Pathologie, Hôpital Ophtalmique Jules-Gonin , 15, avenue de France, 1004, Lausanne, Switzerland
| | - Marc Putterman
- APHP, Service de Pathologie de l'Hôpital Universitaire Necker-Enfants-Malades, Université Paris Descartes, 149 rue de Sèvres, 75015, Paris, France
| | - Fabien Guimiot
- Unité Fonctionnelle de Foeto-Pathologie, Hôpital Universitaire Robert Debré, 48 Boulevard Serrurier, 75019, Paris, France
| | - Thierry Molina
- APHP, Service de Pathologie de l'Hôpital Universitaire Necker-Enfants-Malades, Université Paris Descartes, 149 rue de Sèvres, 75015, Paris, France
| | - Benoît Terris
- APHP, Service de Pathologie de L'Hôpital Cochin-Hôtel-Dieu, Université Paris Descartes, 27 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Dominique Brémond-Gignac
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France
| | - Francine Behar-Cohen
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- AP-HP, Service d'Ophtalmologie, Hôpital Universitaire Cochin-Hôtel-Dieu, 27 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Marc M Abitbol
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France.
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France.
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12
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Abstract
This chapter provides an overview of the early developmental origins of six ocular tissues: the cornea, lens, ciliary body, iris, neural retina, and retina pigment epithelium. Many of these tissue types are concurrently specified and undergo a complex set of morphogenetic movements that facilitate their structural interconnection. Within the context of vertebrate eye organogenesis, we also discuss the genetic hierarchies of transcription factors and signaling pathways that regulate growth, patterning, cell type specification and differentiation.
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Affiliation(s)
- Joel B Miesfeld
- Department of Cell Biology & Human Anatomy, University of California Davis School of Medicine, Davis, CA, United States
| | - Nadean L Brown
- Department of Cell Biology & Human Anatomy, University of California Davis School of Medicine, Davis, CA, United States.
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13
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Martynova E, Bouchard M, Musil LS, Cvekl A. Identification of Novel Gata3 Distal Enhancers Active in Mouse Embryonic Lens. Dev Dyn 2018; 247:1186-1198. [PMID: 30295986 PMCID: PMC6246825 DOI: 10.1002/dvdy.24677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/30/2018] [Accepted: 10/01/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The tissue-specific transcriptional programs during normal development require tight control by distal cis-regulatory elements, such as enhancers, with specific DNA sequences recognized by transcription factors, coactivators, and chromatin remodeling enzymes. Gata3 is a sequence-specific DNA-binding transcription factor that regulates formation of multiple tissues and organs, including inner ear, lens, mammary gland, T-cells, urogenital system, and thyroid gland. In the eye, Gata3 has a highly restricted expression domain in the posterior part of the lens vesicle; however, the underlying regulatory mechanisms are unknown. RESULTS Here we describe the identification of a novel bipartite Gata3 lens-specific enhancer located ∼18 kb upstream from its transcriptional start site. We also found that a 5-kb Gata3 promoter possesses low activity in the lens. The bipartite enhancer contains arrays of AP-1, Ets-, and Smad1/5-binding sites as well as binding sites for lens-associated DNA-binding factors. Transient transfection studies of the promoter with the bipartite enhancer showed enhanced activation by BMP4 and FGF2. CONCLUSIONS These studies identify a novel distal enhancer of Gata3 with high activity in lens and indicate that BMP and FGF signaling can up-regulate expression of Gata3 in differentiating lens fiber cells through the identified Gata3 enhancer and promoter elements. Developmental Dynamics 247:1186-1198, 2018. © 2018 The Authors. Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
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Affiliation(s)
- Elena Martynova
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, New York
| | - Maxime Bouchard
- Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Linda S Musil
- Department of Biochemistry and Molecular Biology, Oregon Health Science University, Portland, Oregon
| | - Ales Cvekl
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, New York
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14
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Azimi M, Le TT, Brown NL. Presenilin gene function and Notch signaling feedback regulation in the developing mouse lens. Differentiation 2018; 102:40-52. [PMID: 30059908 DOI: 10.1016/j.diff.2018.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/06/2018] [Accepted: 07/24/2018] [Indexed: 12/25/2022]
Abstract
Presenilins (Psen1 and Psen2 in mice) are polytopic transmembrane proteins that act in the γ-secretase complex to make intra-membrane cleavages of their substrates, including the well-studied Notch receptors. Such processing releases the Notch intracellular domain, allowing it to physically relocate from the cell membrane to the nucleus where it acts in a transcriptional activating complex to regulate downstream genes in the signal-receiving cell. Previous studies of Notch pathway mutants for Jagged1, Notch2, and Rbpj demonstrated that canonical signaling is a necessary component of normal mouse lens development. However, the central role of Psens within the γ-secretase complex has never been explored in any developing eye tissue or cell type. By directly comparing Psen single and double mutant phenotypes during mouse lens development, we found a stronger requirement for Psen1, although both genes are needed for progenitor cell growth and to prevent apoptosis. We also uncovered a novel genetic interaction between Psen1 and Jagged1. By quantifying protein and mRNA levels of key Notch pathway genes in Psen1/2 or Jagged1 mutant lenses, we identified multiple points in the overall signaling cascade where feedback regulation can occur. Our data are consistent with the loss of particular genes indirectly influencing the transcription level of another. However, we conclude that regulating Notch2 protein levels is particularly important during normal signaling, supporting the importance of post-translational regulatory mechanisms in this tissue.
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Affiliation(s)
- Mina Azimi
- Department of Cell Biology & Human Anatomy; University of California, Davis One Shields Avenue, Davis, CA 95616, USA
| | - Tien T Le
- Division of Developmental Biology, Cincinnati Childrens Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Nadean L Brown
- Department of Cell Biology & Human Anatomy; University of California, Davis One Shields Avenue, Davis, CA 95616, USA; Division of Developmental Biology, Cincinnati Childrens Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
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15
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Abstract
In this review, we compare and contrast the three different forms of vertebrate lens regeneration: Wolffian lens regeneration, cornea-lens regeneration, and lens regeneration from lens epithelial cells. An examination of the diverse cellular origins of these lenses, their unique phylogenetic distribution, and the underlying molecular mechanisms, suggests that these different forms of lens regeneration evolved independently and utilize neither conserved nor convergent mechanisms to regulate these processes.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL
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16
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Yu Z, Yu W, Liu J, Wu D, Wang C, Zhang J, Zhao J. Lens-specific deletion of the Msx2 gene increased apoptosis by enhancing the caspase-3/caspase-8 signaling pathway. J Int Med Res 2018; 46:2843-2855. [PMID: 29921154 PMCID: PMC6124292 DOI: 10.1177/0300060518774687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective To investigate the influence of Msx2 conditional gene knockout during lens development in mice. Methods Lens-specific Msx2 knockout mice were generated using the Cre-loxP system. The eyes of Msx2 conditional knockout ( Msx2CKO) and wild-type ( Msx2WT) mice were examined during embryonic and early postnatal periods using histological, immunofluorescence, in situ hybridization, cell proliferation, apoptosis, and mRNA microarray analyses. Results Msx2CKO mice exhibited small lens formation and microphthalmia after birth, while Msx2CKO embryos exhibited a persistent lens stalk, small lens formation, and microphthalmia. Conditional deletion of Msx2 also led to an increased apoptosis rate, a significant reduction in FoxE3 expression, and an upregulation of Prox1 expression in the lens vesicle during the early embryonic period. Microarray comparison of Msx2CKO and Msx2WT lens transcriptomes identified a large number of differentially expressed genes. Real-time PCR showed that Casp8 and Casp3 expression was upregulated in Msx2CKO mice at post-natal day 1. Conclusion The activation of apoptosis through the caspase-8/caspase-3 signaling pathway, together with the downregulation of FoxE3 expression, appeared to account for the smaller lens formation in Msx2CKO mice.
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Affiliation(s)
- Ziyan Yu
- 1 Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Provincial Key Laboratory of Lens Research, Shenyang, China.,2 Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Wenting Yu
- 1 Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Provincial Key Laboratory of Lens Research, Shenyang, China
| | - Jia Liu
- 1 Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Provincial Key Laboratory of Lens Research, Shenyang, China
| | - Danhong Wu
- 3 Department of Neurology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Chunxia Wang
- 1 Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Provincial Key Laboratory of Lens Research, Shenyang, China
| | - Jinsong Zhang
- 1 Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Provincial Key Laboratory of Lens Research, Shenyang, China
| | - Jiangyue Zhao
- 1 Department of Ophthalmology, Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Provincial Key Laboratory of Lens Research, Shenyang, China
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17
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Kowtharapu BS, Prakasam RK, Murín R, Koczan D, Stahnke T, Wree A, Jünemann AGM, Stachs O. Role of Bone Morphogenetic Protein 7 (BMP7) in the Modulation of Corneal Stromal and Epithelial Cell Functions. Int J Mol Sci 2018; 19:ijms19051415. [PMID: 29747422 PMCID: PMC5983782 DOI: 10.3390/ijms19051415] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 05/02/2018] [Accepted: 05/07/2018] [Indexed: 12/20/2022] Open
Abstract
In the cornea, healing of the wounded avascular surface is an intricate process comprising the involvement of epithelial, stromal and neuronal cell interactions. These interactions result to the release of various growth factors that play prominent roles during corneal wound healing response. Bone morphogenetic proteins (BMPs) are unique multi-functional potent growth factors of the transforming growth factor-beta (TGF-β) superfamily. Treatment of corneal epithelial cells with substance P and nerve growth factor resulted to an increase in the expression of BMP7 mRNA. Since BMP7 is known to modulate the process of corneal wound healing, in this present study, we investigated the influence of exogenous rhBMP7 on human corneal epithelial cell and stromal cell (SFs) function. To obtain a high-fidelity expression profiling of activated biomarkers and pathways, transcriptome-wide gene-level expression profiling of epithelial cells in the presence of BMP7 was performed. Gene ontology analysis shows BMP7 stimulation activated TGF-β signaling and cell cycle pathways, whereas biological processes related to cell cycle, microtubule and intermediate filament cytoskeleton organization were significantly impacted in corneal epithelial cells. Scratch wound healing assay showed increased motility and migration of BMP7 treated epithelial cells. BMP7 stimulation studies show activation of MAPK cascade proteins in epithelial cells and SFs. Similarly, a difference in the expression of claudin, Zink finger E-box-binding homeobox 1 was observed along with phosphorylation levels of cofilin in epithelial cells. Stimulation of SFs with BMP7 activated them with increased expression of α-smooth muscle actin. In addition, an elevated phosphorylation of epidermal growth factor receptor following BMP7 stimulation was also observed both in corneal epithelial cells and SFs. Based on our transcriptome analysis data on epithelial cells and the results obtained in SFs, we conclude that BMP7 contributes to epithelial-to-mesenchymal transition-like responses and plays a role equivalent to TGF-β in the course of corneal wound healing.
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Affiliation(s)
- Bhavani S Kowtharapu
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Ruby Kala Prakasam
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Radovan Murín
- Department of Medical Biochemistry, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 03601 Martin, Slovakia.
| | - Dirk Koczan
- Institute for Immunology, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Thomas Stahnke
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Andreas Wree
- Institute for Anatomy, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Anselm G M Jünemann
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Oliver Stachs
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany.
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18
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Antebi YE, Linton JM, Klumpe H, Bintu B, Gong M, Su C, McCardell R, Elowitz MB. Combinatorial Signal Perception in the BMP Pathway. Cell 2017; 170:1184-1196.e24. [PMID: 28886385 DOI: 10.1016/j.cell.2017.08.015] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 04/26/2017] [Accepted: 08/08/2017] [Indexed: 12/21/2022]
Abstract
The bone morphogenetic protein (BMP) signaling pathway comprises multiple ligands and receptors that interact promiscuously with one another and typically appear in combinations. This feature is often explained in terms of redundancy and regulatory flexibility, but it has remained unclear what signal-processing capabilities it provides. Here, we show that the BMP pathway processes multi-ligand inputs using a specific repertoire of computations, including ratiometric sensing, balance detection, and imbalance detection. These computations operate on the relative levels of different ligands and can arise directly from competitive receptor-ligand interactions. Furthermore, cells can select different computations to perform on the same ligand combination through expression of alternative sets of receptor variants. These results provide a direct signal-processing role for promiscuous receptor-ligand interactions and establish operational principles for quantitatively controlling cells with BMP ligands. Similar principles could apply to other promiscuous signaling pathways.
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Affiliation(s)
- Yaron E Antebi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - James M Linton
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Heidi Klumpe
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Bogdan Bintu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mengsha Gong
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Christina Su
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Reed McCardell
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute and Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA.
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19
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Wordinger RJ, Clark AF. Bone Morphogenetic Proteins and Their Receptors in the Eye. Exp Biol Med (Maywood) 2016; 232:979-92. [PMID: 17720944 DOI: 10.3181/0510-mr-345] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The human genome encodes at least 42 different members of the transforming growth factor-β superfamily of growth factors. Bone morphogenetic proteins (BMPs) are the largest subfamily of proteins within the transforming growth factor-β superfamily and are involved in numerous cellular functions including development, morphogenesis, cell proliferation, apoptosis, and extracellular matrix synthesis. This article first reviews BMPs and BMP receptors, BMP signaling pathways, and mechanisms controlling BMP signaling. Second, we review BMP and BMP receptor expression during embryonic ocular development/ differentiation and in adult ocular tissues. Lastly, future research directions with respect to BMP, BMP receptors, and ocular tissues are suggested.
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Affiliation(s)
- Robert J Wordinger
- Department of Cell Biology and Genetics, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA.
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20
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Pathania M, Wang Y, Simirskii VN, Duncan MK. β1-integrin controls cell fate specification in early lens development. Differentiation 2016; 92:133-147. [PMID: 27596755 PMCID: PMC5159248 DOI: 10.1016/j.diff.2016.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/05/2016] [Accepted: 08/09/2016] [Indexed: 02/03/2023]
Abstract
Integrins are heterodimeric cell surface molecules that mediate cell-extracellular matrix (ECM) adhesion, ECM assembly, and regulation of both ECM and growth factor induced signaling. However, the developmental context of these diverse functions is not clear. Loss of β1-integrin from the lens vesicle (mouse E10.5) results in abnormal exit of anterior lens epithelial cells (LECs) from the cell cycle and their aberrant elongation toward the presumptive cornea by E12.5. These cells lose expression of LEC markers and initiate expression of the Maf (also known as c-Maf) and Prox1 transcription factors as well as other lens fiber cell markers. β1-integrin null LECs also upregulate the ERK, AKT and Smad1/5/8 phosphorylation indicative of BMP and FGF signaling. By E14.5, β1-integrin null lenses have undergone a complete conversion of all lens epithelial cells into fiber cells. These data suggest that shortly after lens vesicle closure, β1-integrin blocks inappropriate differentiation of the lens epithelium into fibers, potentially by inhibiting BMP and/or FGF receptor activation. Thus, β1-integrin has an important role in fine-tuning the response of the early lens to the gradient of growth factors that regulate lens fiber cell differentiation.
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Affiliation(s)
- Mallika Pathania
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Yan Wang
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Vladimir N Simirskii
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA.
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21
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Audette DS, Scheiblin DA, Duncan MK. The molecular mechanisms underlying lens fiber elongation. Exp Eye Res 2016; 156:41-49. [PMID: 27015931 DOI: 10.1016/j.exer.2016.03.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 03/14/2016] [Accepted: 03/16/2016] [Indexed: 12/28/2022]
Abstract
Lens fiber cells are highly elongated cells with complex membrane morphologies that are critical for the transparency of the ocular lens. Investigations into the molecular mechanisms underlying lens fiber cell elongation were first reported in the 1960s, however, our understanding of the process is still poor nearly 50 years later. This review summarizes what is currently hypothesized about the regulation of lens fiber cell elongation along with the available experimental evidence, and how this information relates to what is known about the regulation of cell shape/elongation in other cell types, particularly neurons.
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Affiliation(s)
- Dylan S Audette
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - David A Scheiblin
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA.
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22
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Huang J, Liu Y, Filas B, Gunhaga L, Beebe DC. Negative and positive auto-regulation of BMP expression in early eye development. Dev Biol 2015; 407:256-64. [PMID: 26407529 DOI: 10.1016/j.ydbio.2015.09.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 09/08/2015] [Accepted: 09/15/2015] [Indexed: 02/09/2023]
Abstract
Previous results have shown that Bone Morphogenetic Protein (BMP) signaling is essential for lens specification and differentiation. How BMP signals are regulated in the prospective lens ectoderm is not well defined. To address this issue we have modulated BMP activity in a chicken embryo pre-lens ectoderm explant assay, and also studied transgenic mice, in which the type I BMP receptors, Bmpr1a and Acvr1, are deleted from the prospective lens ectoderm. Our results show that chicken embryo pre-lens ectoderm cells express BMPs and require BMP signaling for lens specification in vitro, and that in vivo inhibition of BMP signals in the mouse prospective lens ectoderm interrupts lens placode formation and prevents lens invagination. Furthermore, our results provide evidence that BMP expression is negatively auto-regulated in the lens-forming ectoderm, decreasing when the tissue is exposed to exogenous BMPs and increasing when BMP signaling is prevented. In addition, eyes lacking BMP receptors in the prospective lens placode develop coloboma in the adjacent wild type optic cup. In these eyes, Bmp7 expression increases in the ventral optic cup and the normal dorsal-ventral gradient of BMP signaling in the optic cup is disrupted. Pax2 becomes undetectable and expression of Sfrp2 increases in the ventral optic cup, suggesting that increased BMP signaling alter their expression, resulting in failure to close the optic fissure. In summary, our results suggest that negative and positive auto-regulation of BMP expression is important to regulate early eye development.
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Affiliation(s)
- Jie Huang
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA.
| | - Ying Liu
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Benjamen Filas
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Lena Gunhaga
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - David C Beebe
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
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23
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Cvekl A, Ashery-Padan R. The cellular and molecular mechanisms of vertebrate lens development. Development 2014; 141:4432-47. [PMID: 25406393 PMCID: PMC4302924 DOI: 10.1242/dev.107953] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ocular lens is a model system for understanding important aspects of embryonic development, such as cell specification and the spatiotemporally controlled formation of a three-dimensional structure. The lens, which is characterized by transparency, refraction and elasticity, is composed of a bulk mass of fiber cells attached to a sheet of lens epithelium. Although lens induction has been studied for over 100 years, recent findings have revealed a myriad of extracellular signaling pathways and gene regulatory networks, integrated and executed by the transcription factor Pax6, that are required for lens formation in vertebrates. This Review summarizes recent progress in the field, emphasizing the interplay between the diverse regulatory mechanisms employed to form lens progenitor and precursor cells and highlighting novel opportunities to fill gaps in our understanding of lens tissue morphogenesis.
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Affiliation(s)
- Aleš Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA Department of Ophthalmology and Visual Sciences, 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
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24
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Lee S, Griep AE. Loss of Dlg-1 in the mouse lens impairs fibroblast growth factor receptor signaling. PLoS One 2014; 9:e97470. [PMID: 24824078 PMCID: PMC4019587 DOI: 10.1371/journal.pone.0097470] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/20/2014] [Indexed: 01/21/2023] Open
Abstract
Coordination of cell proliferation, differentiation and survival is essential for normal development and maintenance of tissues in the adult organism. Growth factor receptor tyrosine kinase signaling pathways and planar cell polarity pathways are two regulators of many developmental processes. We have previously shown through analysis of mice conditionally null in the lens for the planar cell polarity gene (PCP), Dlg-1, that Dlg-1 is required for fiber differentiation. Herein, we asked if Dlg-1 is a regulator of the Fibroblast growth factor receptor (Fgfr) signaling pathway, which is known to be required for fiber cell differentiation. Western blot analysis of whole fiber cell extracts from control and Dlg-1 deficient lenses showed that levels of the Fgfr signaling intermediates pErk, pAkt, and pFrs2α, the Fgfr target, Erm, and the fiber cell specific protein, Mip26, were reduced in the Dlg-1 deficient fiber cells. The levels of Fgfr2 were decreased in Dlg-1 deficient lenses compared to controls. Conversely, levels of Fgfr1 in Dlg-1 deficient lenses were increased compared to controls. The changes in Fgfr levels were found to be specifically in the triton insoluble, cytoskeletal associated fraction of Dlg-1 deficient lenses. Immunofluorescent staining of lenses from E13.5 embryos showed that expression levels of pErk were reduced in the transition zone, a region of the lens that exhibits PCP, in the Dlg-1 deficient lenses as compared to controls. In control lenses, immunofluorescent staining for Fgfr2 was observed in the epithelium, transition zone and fibers. By E13.5, the intensity of staining for Fgfr2 was reduced in these regions of the Dlg-1 deficient lenses. Thus, loss of Dlg-1 in the lens impairs Fgfr signaling and leads to altered levels of Fgfrs, suggesting that Dlg-1 is a modulator of Fgfr signaling pathway at the level of the receptors and that Dlg-1 regulates fiber cell differentiation through its role in PCP.
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Affiliation(s)
- SungKyoung Lee
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Anne E. Griep
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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25
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Mochizuki T, Masai I. The lens equator: a platform for molecular machinery that regulates the switch from cell proliferation to differentiation in the vertebrate lens. Dev Growth Differ 2014; 56:387-401. [PMID: 24720470 DOI: 10.1111/dgd.12128] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 01/17/2023]
Abstract
The vertebrate lens is a transparent, spheroidal tissue, located in the anterior region of the eye that focuses visual images on the retina. During development, surface ectoderm associated with the neural retina invaginates to form the lens vesicle. Cells in the posterior half of the lens vesicle differentiate into primary lens fiber cells, which form the lens fiber core, while cells in the anterior half maintain a proliferative state as a monolayer lens epithelium. After formation of the primary fiber core, lens epithelial cells start to differentiate into lens fiber cells at the interface between the lens epithelium and the primary lens fiber core, which is called the equator. Differentiating lens fiber cells elongate and cover the old lens fiber core, resulting in growth of the lens during development. Thus, lens fiber differentiation is spatially regulated and the equator functions as a platform that regulates the switch from cell proliferation to cell differentiation. Since the 1970s, the mechanism underlying lens fiber cell differentiation has been intensively studied, and several regulatory factors that regulate lens fiber cell differentiation have been identified. In this review, we focus on the lens equator, where these regulatory factors crosstalk and cooperate to regulate lens fiber differentiation. Normally, lens epithelial cells must pass through the equator to start lens fiber differentiation. However, there are reports that when the lens epithelium structure is collapsed, lens fiber cell differentiation occurs without passing the equator. We also discuss a possible mechanism that represses lens fiber cell differentiation in lens epithelium.
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Affiliation(s)
- Toshiaki Mochizuki
- Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
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Identification and characterization of FGF2-dependent mRNA: microRNA networks during lens fiber cell differentiation. G3-GENES GENOMES GENETICS 2013; 3:2239-55. [PMID: 24142921 PMCID: PMC3852386 DOI: 10.1534/g3.113.008698] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
MicroRNAs (miRNAs) and fibroblast growth factor (FGF) signaling regulate a wide range of cellular functions, including cell specification, proliferation, migration, differentiation, and survival. In lens, both these systems control lens fiber cell differentiation; however, a possible link between these processes remains to be examined. Herein, the functional requirement for miRNAs in differentiating lens fiber cells was demonstrated via conditional inactivation of Dicer1 in mouse (Mus musculus) lens. To dissect the miRNA-dependent pathways during lens differentiation, we used a rat (Rattus norvegicus) lens epithelial explant system, induced by FGF2 to differentiate, followed by mRNA and miRNA expression profiling. Transcriptome and miRNome analysis identified extensive FGF2-regulated cellular responses that were both independent and dependent on miRNAs. We identified 131 FGF2-regulated miRNAs. Seventy-six of these miRNAs had at least two in silico predicted and inversely regulated target mRNAs. Genes modulated by the greatest number of FGF-regulated miRNAs include DNA-binding transcription factors Nfib, Nfat5/OREBP, c-Maf, Ets1, and N-Myc. Activated FGF signaling influenced bone morphogenetic factor/transforming growth factor-β, Notch, and Wnt signaling cascades implicated earlier in lens differentiation. Specific miRNA:mRNA interaction networks were predicted for c-Maf, N-Myc, and Nfib (DNA-binding transcription factors); Cnot6, Cpsf6, Dicer1, and Tnrc6b (RNA to miRNA processing); and Ash1l, Med1/PBP, and Kdm5b/Jarid1b/Plu1 (chromatin remodeling). Three miRNAs, including miR-143, miR-155, and miR-301a, down-regulated expression of c-Maf in the 3′-UTR luciferase reporter assays. These present studies demonstrate for the first time global impact of activated FGF signaling in lens cell culture system and predicted novel gene regulatory networks connected by multiple miRNAs that regulate lens differentiation.
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Yip HK. Retinal stem cells and regeneration of vision system. Anat Rec (Hoboken) 2013; 297:137-60. [PMID: 24293400 DOI: 10.1002/ar.22800] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 09/13/2013] [Indexed: 12/14/2022]
Abstract
The vertebrate retina is a well-characterized model for studying neurogenesis. Retinal neurons and glia are generated in a conserved order from a pool of mutlipotent progenitor cells. During retinal development, retinal stem/progenitor cells (RPC) change their competency over time under the influence of intrinsic (such as transcriptional factors) and extrinsic factors (such as growth factors). In this review, we summarize the roles of these factors, together with the understanding of the signaling pathways that regulate eye development. The information about the interactions between intrinsic and extrinsic factors for retinal cell fate specification is useful to regenerate specific retinal neurons from RPCs. Recent studies have identified RPCs in the retina, which may have important implications in health and disease. Despite the recent advances in stem cell biology, our understanding of many aspects of RPCs in the eye remains limited. PRCs are present in the developing eye of all vertebrates and remain active in lower vertebrates throughout life. In mammals, however, PRCs are quiescent and exhibit very little activity and thus have low capacity for retinal regeneration. A number of different cellular sources of RPCs have been identified in the vertebrate retina. These include PRCs at the retinal margin, pigmented cells in the ciliary body, iris, and retinal pigment epithelium, and Müller cells within the retina. Because PRCs can be isolated and expanded from immature and mature eyes, it is possible now to study these cells in culture and after transplantation in the degenerated retinal tissue. We also examine current knowledge of intrinsic RPCs, and human embryonic stems and induced pluripotent stem cells as potential sources for cell transplant therapy to regenerate the diseased retina.
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Affiliation(s)
- Henry K Yip
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Adminstrative Region, People's Republic of China; Research Center of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Adminstrative Region, People's Republic of China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong Special Adminstrative Region, People's Republic of China
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Antosova B, Smolikova J, Borkovcova R, Strnad H, Lachova J, Machon O, Kozmik Z. Ectopic activation of Wnt/β-catenin signaling in lens fiber cells results in cataract formation and aberrant fiber cell differentiation. PLoS One 2013; 8:e78279. [PMID: 24205179 PMCID: PMC3813504 DOI: 10.1371/journal.pone.0078279] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 09/09/2013] [Indexed: 12/04/2022] Open
Abstract
The Wnt/β-catenin signaling pathway controls many processes during development, including cell proliferation, cell differentiation and tissue homeostasis, and its aberrant regulation has been linked to various pathologies. In this study we investigated the effect of ectopic activation of Wnt/β-catenin signaling during lens fiber cell differentiation. To activate Wnt/β-catenin signaling in lens fiber cells, the transgenic mouse referred to as αA-CLEF was generated, in which the transactivation domain of β-catenin was fused to the DNA-binding protein LEF1, and expression of the transgene was controlled by αA-crystallin promoter. Constitutive activation of Wnt/β-catenin signaling in lens fiber cells of αA-CLEF mice resulted in abnormal and delayed fiber cell differentiation. Moreover, adult αA-CLEF mice developed cataract, microphthalmia and manifested downregulated levels of γ-crystallins in lenses. We provide evidence of aberrant expression of cell cycle regulators in embryonic lenses of αA-CLEF transgenic mice resulting in the delay in cell cycle exit and in the shift of fiber cell differentiation to the central fiber cell compartment. Our results indicate that precise regulation of the Wnt/β-catenin signaling activity during later stages of lens development is essential for proper lens fiber cell differentiation and lens transparency.
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Affiliation(s)
- Barbora Antosova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jana Smolikova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Romana Borkovcova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Hynek Strnad
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jitka Lachova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Ondrej Machon
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Zbynek Kozmik
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- * E-mail:
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Henry JJ, Thomas AG, Hamilton PW, Moore L, Perry KJ. Cell signaling pathways in vertebrate lens regeneration. Curr Top Microbiol Immunol 2013; 367:75-98. [PMID: 23224710 DOI: 10.1007/82_2012_289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Certain vertebrates are capable of regenerating parts of the eye, including the lens. Depending on the species, two principal forms of in vivo lens regeneration have been described wherein the new lens arises from either the pigmented epithelium of the dorsal iris or the cornea epithelium. These forms of lens regeneration are triggered by retinal factors present in the eye. Studies have begun to illuminate the nature of the signals that support lens regeneration. This review describes evidence for the involvement of specific signaling pathways in lens regeneration, including the FGF, retinoic acid, TGF-beta, Wnt, and Hedgehog pathways.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL 61801, USA.
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Liu Y, Wang J, Luo Y, Chen S, Lewallen M, Xie T. Stem Cells and Ocular Tissue Regeneration. ASIA-PACIFIC JOURNAL OF OPHTHALMOLOGY (PHILADELPHIA, PA.) 2013; 2:111-8. [PMID: 26108048 DOI: 10.1097/apo.0b013e31828615b7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
PURPOSE Millions worldwide have visual impairments caused by dysfunctional eye components, including cornea, lens, retina, and optic nerve, or the visual cortex in the brain. Insufficient cornea donation and inherent artificial lens problems demand alternative treatment strategies for cornea diseases and cataracts, whereas retinal degenerative diseases, including glaucoma, macular degeneration, and retinitis pigmentosa, still lack effective treatments. Stem cells have been investigated for their potential in various eye-specific pathologies to replace lost retinal ganglion cells and photoreceptors in retinal degenerative diseases and toward engineering transplantable patient-specific cornea or lens. DESIGN Many stem cell types, including putative resident eye stem cells, mesenchymal stem cells, embryonic stem cells, and induced pluripotent stem cells, have been investigated for their potential to generate specific cell types in the eye in culture and after transplantation and to engineer eye tissues in combination with structural scaffolds. METHOD Cultured stem cells and in vitro differentiated eye-specific cells are transplanted into different locations of the eye to test their ability to produce functional cells for supporting eye functions. In addition, stem cells have been directly tested in vitro for their capacity to engineer eye-specific tissues. RESULTS Different stem cell types have been shown to have distinct capacities to produce eye-specific cells or even the entire retina. CONCLUSIONS Stem cells offer great hope for treating various eye pathologies. Despite recent progress, many challenges must still be overcome before the era of stem cell-based therapy in the eye truly arrives.
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Affiliation(s)
- Yizhi Liu
- From the *State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, PR China; and †Stowers Institute for Medical Research, Kansas City, MO
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Madakashira BP, Kobrinski DA, Hancher AD, Arneman EC, Wagner BD, Wang F, Shin H, Lovicu FJ, Reneker LW, Robinson ML. Frs2α enhances fibroblast growth factor-mediated survival and differentiation in lens development. Development 2012; 139:4601-12. [PMID: 23136392 DOI: 10.1242/dev.081737] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Most growth factor receptor tyrosine kinases (RTKs) signal through similar intracellular pathways, but they often have divergent biological effects. Therefore, elucidating the mechanism of channeling the intracellular effect of RTK stimulation to facilitate specific biological responses represents a fundamental biological challenge. Lens epithelial cells express numerous RTKs with the ability to initiate the phosphorylation (activation) of Erk1/2 and PI3-K/Akt signaling. However, only Fgfr stimulation leads to lens fiber cell differentiation in the developing mammalian embryo. Additionally, within the lens, only Fgfrs activate the signal transduction molecule Frs2α. Loss of Frs2α in the lens significantly increases apoptosis and decreases phosphorylation of both Erk1/2 and Akt. Also, Frs2α deficiency decreases the expression of several proteins characteristic of lens fiber cell differentiation, including Prox1, p57(KIP2), aquaporin 0 and β-crystallins. Although not normally expressed in the lens, the RTK TrkC phosphorylates Frs2α in response to binding the ligand NT3. Transgenic lens epithelial cells expressing both TrkC and NT3 exhibit several features characteristic of lens fiber cells. These include elongation, increased Erk1/2 and Akt phosphorylation, and the expression of β-crystallins. All these characteristics of NT3-TrkC transgenic lens epithelial cells depend on Frs2α. Therefore, tyrosine phosphorylation of Frs2α mediates Fgfr-dependent lens cell survival and provides a mechanistic basis for the unique fiber-differentiating capacity of Fgfs on mammalian lens epithelial cells.
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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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Primary cultures of embryonic chick lens cells as a model system to study lens gap junctions and fiber cell differentiation. J Membr Biol 2012; 245:357-68. [PMID: 22797938 DOI: 10.1007/s00232-012-9458-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/20/2012] [Indexed: 01/31/2023]
Abstract
A major limitation in lens gap junction research has been the lack of experimentally tractable ex vivo systems to study the formation and regulation of fiber-type gap junctions. Although immortalized lens-derived cell lines are amenable to both gene transfection and siRNA-mediated knockdown, to our knowledge none are capable of undergoing appreciable epithelial-to-fiber differentiation. Lens central epithelial explants have the converse limitation. A key advance in the field was the development of a primary embryonic chick lens cell culture system by Drs. Sue Menko and Ross Johnson. Unlike central epithelial explants, these cultures also include cells from the peripheral (preequatorial and equatorial) epithelium, which is the most physiologically relevant population for the study of fiber-type gap junction formation. We have modified the Menko/Johnson system and refer to our cultures as dissociated cell-derived monolayer cultures (DCDMLs). We culture DCDMLs without serum to mimic the avascular lens environment and on laminin, the major matrix component of the lens capsule. Here, I review the features of the DCDML system and how we have used it to study lens gap junctions and fiber cell differentiation. Our results demonstrate the power of DCDMLs to generate new findings germane to the mammalian lens and how these cultures can be exploited to conduct experiments that would be impossible, prohibitively expensive and/or difficult to interpret using transgenic animals in vivo.
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34
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Grocott T, Tambalo M, Streit A. The peripheral sensory nervous system in the vertebrate head: a gene regulatory perspective. Dev Biol 2012; 370:3-23. [PMID: 22790010 DOI: 10.1016/j.ydbio.2012.06.028] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/28/2012] [Accepted: 06/29/2012] [Indexed: 02/06/2023]
Abstract
In the vertebrate head, crucial parts of the sense organs and sensory ganglia develop from special regions, the cranial placodes. Despite their cellular and functional diversity, they arise from a common field of multipotent progenitors and acquire distinct identity later under the influence of local signalling. Here we present the gene regulatory network that summarises our current understanding of how sensory cells are specified, how they become different from other ectodermal derivatives and how they begin to diversify to generate placodes with different identities. This analysis reveals how sequential activation of sets of transcription factors subdivides the ectoderm over time into smaller domains of progenitors for the central nervous system, neural crest, epidermis and sensory placodes. Within this hierarchy the timing of signalling and developmental history of each cell population is of critical importance to determine the ultimate outcome. A reoccurring theme is that local signals set up broad gene expression domains, which are further refined by mutual repression between different transcription factors. The Six and Eya network lies at the heart of sensory progenitor specification. In a positive feedback loop these factors perpetuate their own expression thus stabilising pre-placodal fate, while simultaneously repressing neural and neural crest specific factors. Downstream of the Six and Eya cassette, Pax genes in combination with other factors begin to impart regional identity to placode progenitors. While our review highlights the wealth of information available, it also points to the lack information on the cis-regulatory mechanisms that control placode specification and of how the repeated use of signalling input is integrated.
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Affiliation(s)
- Timothy Grocott
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Tower Wing, Floor 27, London SE1 9RT, UK
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35
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Qiu X, Yang J, Liu T, Jiang Y, Le Q, Lu Y. Efficient generation of lens progenitor cells from cataract patient-specific induced pluripotent stem cells. PLoS One 2012; 7:e32612. [PMID: 22403680 PMCID: PMC3293838 DOI: 10.1371/journal.pone.0032612] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 01/31/2012] [Indexed: 12/18/2022] Open
Abstract
The development of a technique to induce the transformation of somatic cells to a pluripotent state via the ectopic expression of defined transcription factors was a transformational event in the field of regenerative medicine. The development of this technique also impacted ophthalmology, as patient-specific induced pluripotent stemcells (iPSCs) may be useful resources for some ophthalmological diseases. The lens is a key refractive element in the eye that focuses images of the visual world onto the retina. To establish a new model for drug screening to treat lens diseases and investigating lens aging and development, we examined whether human lens epithelial cells (HLECs) could be induced into iPSCs and if lens-specific differentiation of these cells could be achieved under defined chemical conditions. We first efficiently reprogrammed HLECs from age-related cataract patients to iPSCs with OCT-4, SOX-2, and KLF-4. The resulting HLEC-derived iPS (HLE-iPS) colonies were indistinguishable from human ES cells with respect to morphology, gene expression, pluripotent marker expression and their ability to generate all embryonic germ-cell layers. Next, we performed a 3-step induction procedure: HLE-iPS cells were differentiated into large numbers of lens progenitor-like cells with defined factors (Noggin, BMP and FGF2), and we determined that these cells expressed lens-specific markers (PAX6, SOX2, SIX3, CRYAB, CRYAA, BFSP1, and MIP). In addition, HLE-iPS-derived lens cells exhibited reduced expression of epithelial mesenchymal transition (EMT) markers compared with human embryonic stem cells (hESCs) and fibroblast-derived iPSCs. Our study describes a highly efficient procedure for generating lens progenitor cells from cataract patient HLEC-derived iPSCs. These patient-derived pluripotent cells provide a valuable model for studying the developmental and molecular biological mechanisms that underlie cell determination in lens development and cataract pathophysiology.
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Affiliation(s)
- Xiaodi Qiu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Jin Yang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Tianjin Liu
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy for Sciences, Shanghai, People's Republic of China
| | - Yongxiang Jiang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Qihua Le
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Yi Lu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
- * E-mail:
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Kiselev Y, Eriksen TE, Forsdahl S, Nguyen LHT, Mikkola I. 3T3 cell lines stably expressing Pax6 or Pax6(5a)--a new tool used for identification of common and isoform specific target genes. PLoS One 2012; 7:e31915. [PMID: 22384097 PMCID: PMC3285655 DOI: 10.1371/journal.pone.0031915] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 01/19/2012] [Indexed: 12/03/2022] Open
Abstract
Pax6 and Pax6(5a) are two isoforms of the evolutionary conserved Pax6 gene often co-expressed in specific stochiometric relationship in the brain and the eye during development. The Pax6(5a) protein differs from Pax6 by having a 14 amino acid insert in the paired domain, causing the two proteins to have different DNA binding specificities. Difference in functions during development is proven by the fact that mutations in the 14 amino acid insertion for Pax6(5a) give a slightly different eye phenotype than the one described for Pax6. Whereas quite many Pax6 target genes have been published during the last years, few Pax6(5a) specific target genes have been reported on. However, target genes identified by Pax6 knockout studies can probably be Pax6(5a) targets as well, since this isoform also will be affected by the knockout. In order to identify new Pax6 target genes, and to try to distinguish between genes regulated by Pax6 and Pax6(5a), we generated FlpIn-3T3 cell lines stably expressing Pax6 or Pax6(5a). RNA was harvested from these cell lines and used in gene expression microarrays where we identified a number of genes differentially regulated by Pax6 and Pax6(5a). A majority of these were associated with the extracellular region. By qPCR we verified that Ncam1, Ngef, Sphk1, Dkk3 and Crtap are Pax6(5a) specific target genes, while Tgfbi, Vegfa, EphB2, Klk8 and Edn1 were confirmed as Pax6 specific target genes. Nbl1, Ngfb and seven genes encoding different glycosyl transferases appeared to be regulated by both. Direct binding to the promoters of Crtap, Ctgf, Edn1, Dkk3, Pdgfb and Ngef was verified by ChIP. Furthermore, a change in morphology of the stably transfected Pax6 and Pax6(5a) cells was observed, and the Pax6 expressing cells were shown to have increased proliferation and migration capacities.
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Affiliation(s)
| | | | | | | | - Ingvild Mikkola
- Research Group of Pharmacology, Department of Pharmacy, University of Tromsø, Tromsø, Norway
- * E-mail:
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Tsau C, Ito M, Gromova A, Hoffman MP, Meech R, Makarenkova HP. Barx2 and Fgf10 regulate ocular glands branching morphogenesis by controlling extracellular matrix remodeling. Development 2011; 138:3307-17. [PMID: 21750040 DOI: 10.1242/dev.066241] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The lacrimal gland (LG) develops through branching morphogenesis and produces secretions, including tears, that lubricate and protect the ocular surface. Despite the prevalence of LG disorders such as dry eye, relatively little is known about the regulation of LG development. In this study, we show that the homeobox transcription factor Barx2 is highly expressed in conjunctival epithelium, eyelids and ocular [lacrimal, harderian (HG), and meibomian (MG)] glands and is necessary for normal ocular gland and eyelid development. Barx2(-/-) mice show defective LG morphogenesis, absence of the HG, and defects in MG and eyelid fusion. Ex vivo antisense assays confirm the requirement for Barx2 in LG bud elongation and branching. Gene expression profiles reveal decreased expression of several adhesion and matrix remodeling molecules in Barx2(-/-) LGs. In culture, Barx2 regulates expression of matrix metalloproteinases (MMPs) and epithelial cell migration through the extracellular matrix. Fibroblast growth factors are crucial regulators of LG development and we show that Barx2 is required for Fgf10-induced LG bud elongation and that both Barx2 and Fgf10 cooperate in the regulation of MMPs. Together, these data suggest a mechanism for the effects of loss of Barx2 on ocular gland development. Intriguingly, salivary glands that also express a high level of Barx2 develop normally in Barx2(-/-) mice and do not show altered levels of MMPs. Thus, the function of Barx2 is specific to ocular gland development. Based on our data, we propose a functional network involving Barx2, Fgf10 and MMPs that plays an essential role in regulating branching morphogenesis of the ocular glands.
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Affiliation(s)
- Cindy Tsau
- The Neurosciences Institute, San Diego, CA 92121, USA
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38
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The lens in focus: a comparison of lens development in Drosophila and vertebrates. Mol Genet Genomics 2011; 286:189-213. [PMID: 21877135 DOI: 10.1007/s00438-011-0643-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 08/04/2011] [Indexed: 12/24/2022]
Abstract
The evolution of the eye has been a major subject of study dating back centuries. The advent of molecular genetics offered the surprising finding that morphologically distinct eyes rely on conserved regulatory gene networks for their formation. While many of these advances often stemmed from studies of the compound eye of the fruit fly, Drosophila melanogaster, and later translated to discoveries in vertebrate systems, studies on vertebrate lens development far outnumber those in Drosophila. This may be largely historical, since Spemann and Mangold's paradigm of tissue induction was discovered in the amphibian lens. Recent studies on lens development in Drosophila have begun to define molecular commonalities with the vertebrate lens. Here, we provide an overview of Drosophila lens development, discussing intrinsic and extrinsic factors controlling lens cell specification and differentiation. We then summarize key morphological and molecular events in vertebrate lens development, emphasizing regulatory factors and networks strongly associated with both systems. Finally, we provide a comparative analysis that highlights areas of research that would help further clarify the degree of conservation between the formation of dioptric systems in invertebrates and vertebrates.
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39
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Gunhaga L. The lens: a classical model of embryonic induction providing new insights into cell determination in early development. Philos Trans R Soc Lond B Biol Sci 2011; 366:1193-203. [PMID: 21402580 DOI: 10.1098/rstb.2010.0175] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The lens was the first tissue in which the concept of embryonic induction was demonstrated. For many years lens induction was thought to occur at the time the optic vesicle and lens placode came in contact. Since then, studies have revealed that lens placodal progenitor cells are specified already at gastrula stages, much earlier than previously believed, and independent of optic vesicle interactions. In this review, I will focus on how individual signalling molecules, in particular BMP, FGF, Wnt and Shh, regulate the initial specification of lens placodal cells and the progressive development of lens cells. I will discuss recent work that has shed light on the combination of signalling molecules and the molecular interactions that affect lens specification and proper lens formation. I will also discuss proposed tissue interactions important for lens development. A greater knowledge of the molecular interactions during lens induction is likely to have practical benefits in understanding the causes and consequences of lens diseases. Moreover, knowledge regarding lens induction is providing fundamental important insights into inductive processes in development in general.
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Affiliation(s)
- Lena Gunhaga
- Umeå Center for Molecular Medicine, Umeå University, Building 6M, 4th floor, 901 87 Umeå, Sweden.
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40
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Dahm R, van Marle J, Quinlan RA, Prescott AR, Vrensen GFJM. Homeostasis in the vertebrate lens: mechanisms of solute exchange. Philos Trans R Soc Lond B Biol Sci 2011; 366:1265-77. [PMID: 21402585 DOI: 10.1098/rstb.2010.0299] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The eye lens is avascular, deriving nutrients from the aqueous and vitreous humours. It is, however, unclear which mechanisms mediate the transfer of solutes between these humours and the lens' fibre cells (FCs). In this review, we integrate the published data with the previously unpublished ultrastructural, dye loading and magnetic resonance imaging results. The picture emerging is that solute transfer between the humours and the fibre mass is determined by four processes: (i) paracellular transport of ions, water and small molecules along the intercellular spaces between epithelial and FCs, driven by Na(+)-leak conductance; (ii) membrane transport of such solutes from the intercellular spaces into the fibre cytoplasm by specific carriers and transporters; (iii) gap-junctional coupling mediating solute flux between superficial and deeper fibres, Na(+)/K(+)-ATPase-driven efflux of waste products in the equator, and electrical coupling of fibres; and (iv) transcellular transfer via caveoli and coated vesicles for the uptake of macromolecules and cholesterol. There is evidence that the Na(+)-driven influx of solutes occurs via paracellular and membrane transport and the Na(+)/K(+)-ATPase-driven efflux of waste products via gap junctions. This micro-circulation is likely restricted to the superficial cortex and nearly absent beyond the zone of organelle loss, forming a solute exchange barrier in the lens.
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Affiliation(s)
- Ralf Dahm
- Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria.
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41
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Pandit T, Jidigam VK, Gunhaga L. BMP-induced L-Maf regulates subsequent BMP-independent differentiation of primary lens fibre cells. Dev Dyn 2011; 240:1917-28. [DOI: 10.1002/dvdy.22692] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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42
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Lovicu FJ, McAvoy JW, de Iongh RU. Understanding the role of growth factors in embryonic development: insights from the lens. Philos Trans R Soc Lond B Biol Sci 2011; 366:1204-18. [PMID: 21402581 PMCID: PMC3061110 DOI: 10.1098/rstb.2010.0339] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Growth factors play key roles in influencing cell fate and behaviour during development. The epithelial cells and fibre cells that arise from the lens vesicle during lens morphogenesis are bathed by aqueous and vitreous, respectively. Vitreous has been shown to generate a high level of fibroblast growth factor (FGF) signalling that is required for secondary lens fibre differentiation. However, studies also show that FGF signalling is not sufficient and roles have been identified for transforming growth factor-β and Wnt/Frizzled families in regulating aspects of fibre differentiation. In the case of the epithelium, key roles for Wnt/β-catenin and Notch signalling have been demonstrated in embryonic development, but it is not known if other factors are required for its formation and maintenance. This review provides an overview of current knowledge about growth factor regulation of differentiation and maintenance of lens cells. It also highlights areas that warrant future study.
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Affiliation(s)
- F. J. Lovicu
- Discipline of Anatomy and Histology, Bosch Institute, University of Sydney, NSW 2006, Australia
- Save Sight Institute, University of Sydney, Sydney, NSW 2001, Australia
- Vision Cooperative Research Centre, Sydney, Australia
| | - J. W. McAvoy
- Save Sight Institute, University of Sydney, Sydney, NSW 2001, Australia
- Vision Cooperative Research Centre, Sydney, Australia
| | - R. U. de Iongh
- Anatomy and Cell Biology, University of Melbourne, Victoria 3010, Australia
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43
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Wiley LA, Rajagopal R, Dattilo LK, Beebe DC. The tumor suppressor gene Trp53 protects the mouse lens against posterior subcapsular cataracts and the BMP receptor Acvr1 acts as a tumor suppressor in the lens. Dis Model Mech 2011; 4:484-95. [PMID: 21504908 PMCID: PMC3124053 DOI: 10.1242/dmm.006593] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We previously found that lenses lacking the Acvr1 gene, which encodes a bone morphogenetic protein (BMP) receptor, had abnormal proliferation and cell death in epithelial and cortical fiber cells. We tested whether the tumor suppressor protein p53 (encoded by Trp53) affected this phenotype. Acvr1 conditional knockout (Acvr1CKO) mouse fiber cells had increased numbers of nuclei that stained for p53 phosphorylated on serine 15, an indicator of p53 stabilization and activation. Deletion of Trp53 rescued the Acvr1CKO cell death phenotype in embryos and reduced Acvr1-dependent apoptosis in postnatal lenses. However, deletion of Trp53 alone increased the number of fiber cells that failed to withdraw from the cell cycle. Trp53CKO and Acvr1;Trp53DCKO (double conditional knockout), but not Acvr1CKO, lenses developed abnormal collections of cells at the posterior of the lens that resembled posterior subcapsular cataracts. Cells from human posterior subcapsular cataracts had morphological and molecular characteristics similar to the cells at the posterior of mouse lenses lacking Trp53. In Trp53CKO lenses, cells in the posterior plaques did not proliferate but, in Acvr1;Trp53DCKO lenses, many cells in the posterior plaques continued to proliferate, eventually forming vascularized tumor-like masses at the posterior of the lens. We conclude that p53 protects the lens against posterior subcapsular cataract formation by suppressing the proliferation of fiber cells and promoting the death of any fiber cells that enter the cell cycle. Acvr1 acts as a tumor suppressor in the lens. Enhancing p53 function in the lens could contribute to the prevention of steroid- and radiation-induced posterior subcapsular cataracts.
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Affiliation(s)
- Luke A Wiley
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO 63110, USA
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Qu X, Hertzler K, Pan Y, Grobe K, Robinson ML, Zhang X. Genetic epistasis between heparan sulfate and FGF-Ras signaling controls lens development. Dev Biol 2011; 355:12-20. [PMID: 21536023 DOI: 10.1016/j.ydbio.2011.04.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/14/2011] [Accepted: 04/01/2011] [Indexed: 02/06/2023]
Abstract
Vertebrate lens development depends on a complex network of signaling molecules to coordinate cell proliferation, migration and differentiation. In this study, we have investigated the role of heparan sulfate in lens specific signaling by generating a conditional ablation of heparan sulfate modification genes, Ndst1 and Ndst2. In this mutant, N-sulfation of heparan sulfate was disrupted after the lens induction stage, resulting in reduced lens cell proliferation, increased cell death and defective lens fiber differentiation in later lens development. The loss of Ndst function also prevented the assembly of Fgf/Fgfr complexes on the lens cell surface and disrupted ERK signaling within the lens. We further demonstrated that Ndst mutation completely inhibited the FGF1 and Fgf3 overexpression phenotypes, but Kras reactivation was sufficient to reverse the Ndst deficient lens differentiation defect. The epistatic relationship between Ndst and FGF-Ras signaling demonstrates that FGF signaling is the predominant signaling pathway controlled by Ndst in lens development.
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Affiliation(s)
- Xiuxia Qu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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45
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Perry KJ, Johnson VR, Malloch EL, Fukui L, Wever J, Thomas AG, Hamilton PW, Henry JJ. The G-protein-coupled receptor, GPR84, is important for eye development in Xenopus laevis. Dev Dyn 2011; 239:3024-37. [PMID: 20925114 DOI: 10.1002/dvdy.22446] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) represent diverse, multifamily groups of cell signaling receptors involved in many cellular processes. We identified Xenopus laevis GPR84 as a member of the A18 subfamily of GPCRs. During development, GPR84 is detected in the embryonic lens placode, differentiating lens fiber cells, retina, and cornea. Anti-sense morpholino oligonucleotide-mediated knockdown and RNA rescue experiments demonstrate GPR84's importance in lens, cornea, and retinal development. Examination of cell proliferation using an antibody against histone H3 S10P reveals significant increases in the lens and retina following GPR84 knockdown. Additionally, there was also an increase in apoptosis in the retina and lens, as revealed by TUNEL assay. Reciprocal transplantation of the presumptive lens ectoderm between uninjected controls and morpholino-injected embryos demonstrates that GPR84 is necessary in the retina for proper development of the retina, as well as other eye tissues including the lens and cornea.
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Affiliation(s)
- Kimberly J Perry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illionis 61801, USA
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46
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Lachke SA, Maas RL. Building the developmental oculome: systems biology in vertebrate eye development and disease. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 2:305-323. [PMID: 20836031 DOI: 10.1002/wsbm.59] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The vertebrate eye is a sophisticated multicomponent organ that has been actively studied for over a century, resulting in the identification of the major embryonic and molecular events involved in its complex developmental program. Data gathered so far provides sufficient information to construct a rudimentary network of the various signaling molecules, transcription factors, and their targets for several key stages of this process. With the advent of genomic technologies, there has been a rapid expansion in our ability to collect and process biological information, and the use of systems-level approaches to study specific aspects of vertebrate eye development has already commenced. This is beginning to result in the definition of the dynamic developmental networks that operate in ocular tissues, and the interactions of such networks between coordinately developing ocular tissues. Such an integrative understanding of the eye by a comprehensive systems-level analysis can be termed the 'oculome', and that of serial developmental stages of the eye as it transits from its initiation to a fully formed functional organ represents the 'developmental oculome'. Construction of the developmental oculome will allow novel mechanistic insights that are essential for organ regeneration-based therapeutic applications, and the generation of computational models for eye disease states to predict the effects of drugs. This review discusses our present understanding of two of the individual components of the developing vertebrate eye--the lens and retina--at both the molecular and systems levels, and outlines the directions and tools required for construction of the developmental oculome.
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Affiliation(s)
- Salil A Lachke
- Division of Genetics, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Richard L Maas
- Division of Genetics, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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Liu Y, Kawai K, Khashabi S, Deng C, Liu YH, Yiu S. Inactivation of Smad4 leads to impaired ocular development and cataract formation. Biochem Biophys Res Commun 2010; 400:476-82. [PMID: 20735985 DOI: 10.1016/j.bbrc.2010.08.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 08/17/2010] [Indexed: 12/14/2022]
Abstract
PURPOSE Signaling by members of the TGFβ superfamily of molecules is essential for embryonic development and homeostasis. Smad4, a key intracellular mediator in TGFβ signaling, forms transcriptional activator complexes with Activin-, BMP-, and TGFβ-restricted Smad proteins. However, the functional role of Smad4 in controlling different visual system compartments has not been fully investigated. METHODS Using the Pax6 promoter-driven Cre transgenic, smad4 was conditionally inactivated in the lens, cornea and ectoderm of the eyelids. Standard histological and molecular analytical approaches were employed to reveal morphological and cellular changes. RESULTS Inactivation of Smad4 in the lens led to microphthalmia and cataract formation in addition to the persistent adhesion of the retina to the lens and the iris to the cornea. Inactivation of Smad4 from the ectoderm of the eyelid and cornea caused disruption to eyelid fusion and proper development of the corneal epithelium and corneal stroma. CONCLUSIONS Smad4 is required for the development and maintenance of the lens in addition to the proper development of the cornea, eyelids, and retina.
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Affiliation(s)
- Ying Liu
- Department of Ophthalmology and Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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48
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Yang C, Yang Y, Brennan L, Bouhassira EE, Kantorow M, Cvekl A. Efficient generation of lens progenitor cells and lentoid bodies from human embryonic stem cells in chemically defined conditions. FASEB J 2010; 24:3274-83. [PMID: 20410439 DOI: 10.1096/fj.10-157255] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The eye lens is an encapsulated avascular organ whose function is to focus light on the retina. Lens comprises a single progenitor cell lineage in multiple states of differentiation. Disruption of lens function leading to protein aggregation and opacity results in age-onset cataract. Cataract is a complex disease involving genetic and environmental factors. Here, we report the development of a new 3-stage system that differentiates human embryonic stem cells (hESCs) into large quantities of lens progenitor-like cells and differentiated 3-dimensional lentoid bodies. Inhibition of BMP signaling by noggin triggered differentiation of hESCs toward neuroectoderm. Subsequent reactivation of BMP and activation of FGF signaling stimulated formation of lens progenitor cells marked by the expression of PAX6 and alpha-crystallins. The formation of lentoid bodies was most efficient in the presence of FGF2 and Wnt-3a, yielding approximately 1000 lentoid bodies/30-mm well. Lentoid bodies expressed and accumulated lens-specific markers including alphaA-, alphaB-, beta-, and gamma-crystallins, filensin, CP49, and MIP/aquaporin 0. Collectively, these studies identify a novel procedure to generate lens cells from hESCs that can be applied for studies of lens differentiation and cataractogenesis using induced pluripotent stem (iPS) cells derived from various cataract patients.
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Affiliation(s)
- Chunbo Yang
- Department of Ophthalmology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA
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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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50
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Abstract
The vertebrate eye comprises tissues from different embryonic origins: the lens and the cornea are derived from the surface ectoderm, but the retina and the epithelial layers of the iris and ciliary body are from the anterior neural plate. The timely action of transcription factors and inductive signals ensure the correct development of the different eye components. Establishing the genetic basis of eye defects in zebrafishes, mouse, and human has been an important tool for the detailed analysis of this complex process. A single eye field forms centrally within the anterior neural plate during gastrulation; it is characterized on the molecular level by the expression of "eye-field transcription factors." The single eye field is separated into two, forming the optic vesicle and later (under influence of the lens placode) the optic cup. The lens develops from the lens placode (surface ectoderm) under influence of the underlying optic vesicle. Pax6 acts in this phase as master control gene, and genes encoding cytoskeletal proteins, structural proteins, or membrane proteins become activated. The cornea forms from the surface ectoderm, and cells from the periocular mesenchyme migrate into the cornea giving rise for the future cornea stroma. Similarly, the iris and ciliary body form from the optic cup. The outer layer of the optic cup becomes the retinal pigmented epithelium, and the main part of the inner layer of the optic cup forms later the neural retina with six different types of cells including the photoreceptors. The retinal ganglion cells grow toward the optic stalk forming the optic nerve. This review describes the major molecular players and cellular processes during eye development as they are known from frogs, zebrafish, chick, and mice-showing also differences among species and missing links for future research. The relevance to human disorders is one of the major aspects covered throughout the review.
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Affiliation(s)
- Jochen Graw
- Helmholtz Center Munich-German Research Center for Environmental Health, Institute of Developmental Genetics, Neuherberg, Germany
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