1
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Fox SC, Widen SA, Asai-Coakwell M, Havrylov S, Benson M, Prichard LB, Baddam P, Graf D, Lehmann OJ, Waskiewicz AJ. BMP3 is a novel locus involved in the causality of ocular coloboma. Hum Genet 2022; 141:1385-1407. [PMID: 35089417 DOI: 10.1007/s00439-022-02430-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/04/2022] [Indexed: 12/29/2022]
Abstract
Coloboma, a congenital disorder characterized by gaps in ocular tissues, is caused when the choroid fissure fails to close during embryonic development. Several loci have been associated with coloboma, but these represent less than 40% of those that are involved with this disease. Here, we describe a novel coloboma-causing locus, BMP3. Whole exome sequencing and Sanger sequencing of patients with coloboma identified three variants in BMP3, two of which are predicted to be disease causing. Consistent with this, bmp3 mutant zebrafish have aberrant fissure closure. bmp3 is expressed in the ventral head mesenchyme and regulates phosphorylated Smad3 in a population of cells adjacent to the choroid fissure. Furthermore, mutations in bmp3 sensitize embryos to Smad3 inhibitor treatment resulting in open choroid fissures. Micro CT scans and Alcian blue staining of zebrafish demonstrate that mutations in bmp3 cause midface hypoplasia, suggesting that bmp3 regulates cranial neural crest cells. Consistent with this, we see active Smad3 in a population of periocular neural crest cells, and bmp3 mutant zebrafish have reduced neural crest cells in the choroid fissure. Taken together, these data suggest that Bmp3 controls Smad3 phosphorylation in neural crest cells to regulate early craniofacial and ocular development.
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Affiliation(s)
- Sabrina C Fox
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Sonya A Widen
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada.,Vienna BioCenter, Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Mika Asai-Coakwell
- Department of Animal and Poultry and Animal Science, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Serhiy Havrylov
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Matthew Benson
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Lisa B Prichard
- Department of Biological Sciences, MacEwan University, Edmonton, AB, Canada
| | - Pranidhi Baddam
- Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Daniel Graf
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ordan J Lehmann
- Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Andrew J Waskiewicz
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada. .,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.
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2
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Patel A, Anderson G, Galea GL, Balys M, Sowden JC. A molecular and cellular analysis of human embryonic optic fissure closure related to the eye malformation coloboma. Development 2020; 147:dev193649. [PMID: 33158926 DOI: 10.1242/dev.193649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/30/2020] [Indexed: 12/28/2022]
Abstract
Ocular coloboma is a congenital eye malformation, resulting from a failure in optic fissure closure (OFC) and causing visual impairment. There has been little study of the epithelial fusion process underlying closure in the human embryo and coloboma aetiology remains poorly understood. We performed RNAseq of cell populations isolated using laser capture microdissection to identify novel human OFC signature genes and probe the expression profile of known coloboma genes, along with a comparative murine analysis. Gene set enrichment patterns showed conservation between species. Expression of genes involved in epithelial-to-mesenchymal transition was transiently enriched in the human fissure margins during OFC at days 41-44. Electron microscopy and histological analyses showed that cells transiently delaminate at the point of closure, and produce cytoplasmic protrusions, before rearranging to form two continuous epithelial layers. Apoptosis was not observed in the human fissure margins. These analyses support a model of human OFC in which epithelial cells at the fissure margins undergo a transient epithelial-to-mesenchymal-like transition, facilitating cell rearrangement to form a complete optic cup.
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Affiliation(s)
- Aara Patel
- UCL Great Ormond Street Institute of Child Health, and NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
| | - Glenn Anderson
- Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Gabriel L Galea
- UCL Great Ormond Street Institute of Child Health, and NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
| | - Monika Balys
- Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Jane C Sowden
- UCL Great Ormond Street Institute of Child Health, and NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
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3
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Yoon KH, Fox SC, Dicipulo R, Lehmann OJ, Waskiewicz AJ. Ocular coloboma: Genetic variants reveal a dynamic model of eye development. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:590-610. [PMID: 32852110 DOI: 10.1002/ajmg.c.31831] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/21/2022]
Abstract
Ocular coloboma is a congenital disorder of the eye where a gap exists in the inferior retina, lens, iris, or optic nerve tissue. With a prevalence of 2-19 per 100,000 live births, coloboma, and microphthalmia, an associated ocular disorder, represent up to 10% of childhood blindness. It manifests due to the failure of choroid fissure closure during eye development, and it is a part of a spectrum of ocular disorders that include microphthalmia and anophthalmia. Use of genetic approaches from classical pedigree analyses to next generation sequencing has identified more than 40 loci that are associated with the causality of ocular coloboma. As we have expanded studies to include singleton cases, hereditability has been very challenging to prove. As such, researchers over the past 20 years, have unraveled the complex interrelationship amongst these 40 genes using vertebrate model organisms. Such research has greatly increased our understanding of eye development. These genes function to regulate initial specification of the eye field, migration of retinal precursors, patterning of the retina, neural crest cell biology, and activity of head mesoderm. This review will discuss the discovery of loci using patient data, their investigations in animal models, and the recent advances stemming from animal models that shed new light in patient diagnosis.
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Affiliation(s)
- Kevin H Yoon
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Sabrina C Fox
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Renée Dicipulo
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Ordan J Lehmann
- Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew J Waskiewicz
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
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4
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Abstract
The glomerular basement membrane (GBM) is a key component of the glomerular capillary wall and is essential for kidney filtration. The major components of the GBM include laminins, type IV collagen, nidogens and heparan sulfate proteoglycans. In addition, the GBM harbours a number of other structural and regulatory components and provides a reservoir for growth factors. New technologies have improved our ability to study the composition and assembly of basement membranes. We now know that the GBM is a complex macromolecular structure that undergoes key transitions during glomerular development. Defects in GBM components are associated with a range of hereditary human diseases such as Alport syndrome, which is caused by defects in the genes COL4A3, COL4A4 and COL4A5, and Pierson syndrome, which is caused by variants in LAMB2. In addition, the GBM is affected by acquired autoimmune disorders and metabolic diseases such as diabetes mellitus. Current treatments for diseases associated with GBM involvement aim to reduce intraglomerular pressure and to treat the underlying cause where possible. As our understanding about the maintenance and turnover of the GBM improves, therapies to replace GBM components or to stimulate GBM repair could translate into new therapies for patients with GBM-associated disease.
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5
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Sinagoga KL, Larimer-Picciani AM, George SM, Spencer SA, Lister JA, Gross JM. Mitf-family transcription factor function is required within cranial neural crest cells to promote choroid fissure closure. Development 2020; 147:dev187047. [PMID: 32541011 PMCID: PMC7375471 DOI: 10.1242/dev.187047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 05/29/2020] [Indexed: 12/13/2022]
Abstract
A crucial step in eye development is the closure of the choroid fissure (CF), a transient structure in the ventral optic cup through which vasculature enters the eye and ganglion cell axons exit. Although many factors have been identified that function during CF closure, the molecular and cellular mechanisms mediating this process remain poorly understood. Failure of CF closure results in colobomas. Recently, MITF was shown to be mutated in a subset of individuals with colobomas, but how MITF functions during CF closure is unknown. To address this issue, zebrafish with mutations in mitfa and tfec, two members of the Mitf family of transcription factors, were analyzed and their functions during CF closure determined. mitfa;tfec mutants possess severe colobomas and our data demonstrate that Mitf activity is required within cranial neural crest cells (cNCCs) during CF closure. In the absence of Mitf function, cNCC migration and localization in the optic cup are perturbed. These data shed light on the cellular mechanisms underlying colobomas in individuals with MITF mutations and identify a novel role for Mitf function in cNCCs during CF closure.
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Affiliation(s)
- Katie L Sinagoga
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Alessandra M Larimer-Picciani
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Stephanie M George
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Samantha A Spencer
- Department of Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - James A Lister
- Department of Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Jeffrey M Gross
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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6
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Gath N, Gross JM. Zebrafish mab21l2 mutants possess severe defects in optic cup morphogenesis, lens and cornea development. Dev Dyn 2019; 248:514-529. [PMID: 31037784 DOI: 10.1002/dvdy.44] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/09/2019] [Accepted: 04/16/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Mutations in MAB21L2 result in severe ocular defects including microphthalmia, anophthalmia, coloboma, microcornea, and cataracts. The molecular and cellular underpinnings of these defects are unknown, as is the normal cellular function of MAB21L2. Zebrafish mab21l2 au10 mutants possess ocular defects resembling those in humans with MAB21L2 mutations, providing an excellent model to characterize mab21l2 functions during eye development. RESULTS mab21l2 -/- mutants possessed a host of ocular defects including microphthalmia and colobomas as well as small, disorganized lenses and cornea dysgenesis. Decreased proliferation, increased cell death, and defects in marker gene expression were detected in the lens. Cell death in the optic stalk was elevated in mab21l2 -/- mutants and the basement membrane between the edges of the choroid fissure failed to break down. Neuronal differentiation in the retina was normal, however. mab21l2 -/- mutant corneas were disorganized, possessed an increased number of cells, some of which proliferated ectopically, and failed to differentiate the corneal stroma. CONCLUSIONS mab21l2 function is required for morphogenesis and cell survival in the lens and optic cup, and basement membrane breakdown in the choroid fissure. mab21l2 function also regulates proliferation in the lens and cornea; in its absence, the lens is small and mispatterned, and corneal morphogenesis and patterning are also disrupted.
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Affiliation(s)
- Natalie Gath
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas.,Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Jeffrey M Gross
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas.,Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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7
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Carrara N, Weaver M, Piedade WP, Vöcking O, Famulski JK. Temporal characterization of optic fissure basement membrane composition suggests nidogen may be an initial target of remodeling. Dev Biol 2019; 452:43-54. [PMID: 31034836 DOI: 10.1016/j.ydbio.2019.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/08/2019] [Accepted: 04/23/2019] [Indexed: 01/26/2023]
Abstract
Fusion of the optic fissure is necessary to complete retinal morphogenesis and ensure proper function of the optic stalk. Failure of this event leads to congenital coloboma, one of the leading causes of pediatric blindness. Mechanistically it is widely accepted that the basement membrane (BM) surrounding the maturing retina needs to be remodeled within the fissure in order to facilitate subsequent epithelial sheet fusion. However, the mechanism driving BM remodeling has yet to be elucidated. As a first step to understanding this critical molecular event we comprehensively characterized the core composition of optic fissure BMs in the zebrafish embryos. Zebrafish optic fissure BMs were found to express laminin a1, a4, b1a, c1 and c3, nidogen 1a, 1b and 2a, collagen IV a1 and a2 as well as perlecan. Furthermore, we observed that laminin, perlecan and collagen IV expression persists in the fissure during fusion, up to 56 hpf, while nidogen expression is downregulated upon initiation of fusion, at 36 hpf. Using immunohistochemistry we also show that nidogen is removed from the BM prior to that of laminin, indicating that remodeling of the BM is an ordered event. Lastly, we characterized retinal morphogenesis in the absence of nidogen function and documented retinal malformation similar to what is observed in laminin mutants. Taken together, we propose a model of BM remodeling where nidogen acts as a linchpin during initiation of optic fissure fusion.
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Affiliation(s)
| | - Megan Weaver
- Department of Biology, University of Kentucky, USA
| | | | | | - J K Famulski
- Department of Biology, University of Kentucky, USA.
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8
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Keeley DP, Sherwood DR. Tissue linkage through adjoining basement membranes: The long and the short term of it. Matrix Biol 2019; 75-76:58-71. [PMID: 29803937 PMCID: PMC6252152 DOI: 10.1016/j.matbio.2018.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/18/2018] [Accepted: 05/21/2018] [Indexed: 01/01/2023]
Abstract
Basement membranes (BMs) are thin dense sheets of extracellular matrix that surround most tissues. When the BMs of neighboring tissues come into contact, they usually slide along one another and act to separate tissues and organs into distinct compartments. However, in certain specialized regions, the BMs of neighboring tissues link, helping to bring tissues together. These BM connections can be transient, such as during tissue fusion events in development, or long-term, as with adult tissues involved with filtration, including the blood brain barrier and kidney glomerulus. The transitory nature of these connections in development and the complexity of tissue filtration systems in adults have hindered the understanding of how juxtaposed BMs fasten together. The recent identification of a BM-BM adhesion system in C. elegans, termed B-LINK (BM linkage), however, is revealing cellular and extracellular matrix components of a nascent tissue adhesion system. We discuss insights gained from studying the B-LINK tissue adhesion system in C. elegans, compare this adhesion with other BM-BM connections in Drosophila and vertebrates, and outline important future directions towards elucidating this fascinating and poorly understood mode of adhesion that joins neighboring tissues.
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Affiliation(s)
- Daniel P Keeley
- Department of Biology, Regeneration Next, Duke University, Box 90338, Durham, NC 27708, USA
| | - David R Sherwood
- Department of Biology, Regeneration Next, Duke University, Box 90338, Durham, NC 27708, USA.
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9
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Bernstein CS, Anderson MT, Gohel C, Slater K, Gross JM, Agarwala S. The cellular bases of choroid fissure formation and closure. Dev Biol 2018; 440:137-151. [PMID: 29803644 DOI: 10.1016/j.ydbio.2018.05.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 04/30/2018] [Accepted: 05/14/2018] [Indexed: 01/11/2023]
Abstract
Defects in choroid fissure (CF) formation and closure lead to coloboma, a major cause of childhood blindness. Despite genetic advances, the cellular defects underlying coloboma remain poorly elucidated due to our limited understanding of normal CF morphogenesis. We address this deficit by conducting high-resolution spatio-temporal analyses of CF formation and closure in the chick, mouse and fish. We show that a small ventral midline invagination initiates CF formation in the medial-proximal optic cup, subsequently extending it dorsally toward the lens, and proximally into the optic stalk. Unlike previously supposed, the optic disc does not form solely as a result of this invagination. Morphogenetic events that alter the shape of the proximal optic cup also direct clusters of outer layer and optic stalk cells to form dorsal optic disc. A cross-species comparison suggests that CF closure can be accomplished by breaking down basement membranes (BM) along the CF margins, and by establishing BM continuity along the dorsal and ventral surfaces of the CF. CF closure is subsequently accomplished via two distinct mechanisms: tissue fusion or the intercalation of various tissues into the inter-CF space. We identify several novel cell behaviors that underlie CF fusion, many of which involve remodeling of the retinal epithelium. In addition to BM disruption, these include NCAD downregulation along the SOX2+ retinal CF margin, and the protrusion or movement of partially polarized retinal cells into the inter-CF space to mediate fusion. Proximally, the inter-CF space does not fuse or narrow and is instead loosely packed with migrating SOX2+/PAX2+/Vimentin+ astrocytes until it is closed by the outgoing optic nerve. Taken together, our results highlight distinct proximal-distal differences in CF morphogenesis and closure and establish detailed cellular models that can be utilized for understanding the genetic bases of coloboma.
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Affiliation(s)
- Cassidy S Bernstein
- Molecular Biosciences Department, University of Texas at Austin, Austin, TX 78712, USA
| | - Mitchell T Anderson
- Molecular Biosciences Department, University of Texas at Austin, Austin, TX 78712, USA
| | - Chintan Gohel
- Molecular Biosciences Department, University of Texas at Austin, Austin, TX 78712, USA
| | - Kayleigh Slater
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jeffrey M Gross
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Seema Agarwala
- Molecular Biosciences Department, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cell and Molecular Biology, University of Texas at Austin, TX 78712, USA; Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, USA.
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10
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Genes and pathways in optic fissure closure. Semin Cell Dev Biol 2017; 91:55-65. [PMID: 29198497 DOI: 10.1016/j.semcdb.2017.10.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/29/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022]
Abstract
Embryonic development of the vertebrate eye begins with the formation of an optic vesicle which folds inwards to form a double-layered optic cup with a fissure on the ventral surface, known as the optic fissure. Closure of the optic fissure is essential for subsequent growth and development of the eye. A defect in this process can leave a gap in the iris, retina or optic nerve, known as a coloboma, which can lead to severe visual impairment. This review brings together current information about genes and pathways regulating fissure closure from human coloboma patients and animal models. It focuses especially on current understanding of the morphological changes and processes of epithelial remodelling occurring at the fissure margins.
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11
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James A, Lee C, Williams AM, Angileri K, Lathrop KL, Gross JM. The hyaloid vasculature facilitates basement membrane breakdown during choroid fissure closure in the zebrafish eye. Dev Biol 2016; 419:262-272. [PMID: 27634568 DOI: 10.1016/j.ydbio.2016.09.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 09/09/2016] [Accepted: 09/09/2016] [Indexed: 12/22/2022]
Abstract
A critical aspect of vertebrate eye development is closure of the choroid fissure (CF). Defects in CF closure result in colobomas, which are a significant cause of childhood blindness worldwide. Despite the growing number of mutated loci associated with colobomas, we have a limited understanding of the cell biological underpinnings of CF closure. Here, we utilize the zebrafish embryo to identify key phases of CF closure and regulators of the process. Utilizing Laminin-111 as a marker for the basement membrane (BM) lining the CF, we determine the spatial and temporal patterns of BM breakdown in the CF, a prerequisite for CF closure. Similarly, utilizing a combination of in vivo time-lapse imaging, β-catenin immunohistochemistry and F-actin staining, we determine that tissue fusion, which serves to close the fissure, follows BM breakdown closely. Periocular mesenchyme (POM)-derived endothelial cells, which migrate through the CF to give rise to the hyaloid vasculature, possess distinct actin foci that correlate with regions of BM breakdown. Disruption of talin1, which encodes a regulator of the actin cytoskeleton, results in colobomas and these correlate with structural defects in the hyaloid vasculature and defects in BM breakdown. cloche mutants, which entirely lack a hyaloid vasculature, also possess defects in BM breakdown in the CF. Taken together, these data support a model in which the hyaloid vasculature and/or the POM-derived endothelial cells that give rise to the hyaloid vasculature contribute to BM breakdown during CF closure.
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Affiliation(s)
- Andrea James
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Chanjae Lee
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
| | - Andre M Williams
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
| | - Krista Angileri
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Kira L Lathrop
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213
| | - Jeffrey M Gross
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
- Department of Developmental Biology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
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12
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Basement Membranes in the Worm: A Dynamic Scaffolding that Instructs Cellular Behaviors and Shapes Tissues. CURRENT TOPICS IN MEMBRANES 2015; 76:337-71. [PMID: 26610919 DOI: 10.1016/bs.ctm.2015.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The nematode worm Caenorhabditis elegans has all the major basement membrane proteins found in vertebrates, usually with a smaller gene family encoding each component. With its powerful forward genetics, optical clarity, simple tissue organization, and the capability to functionally tag most basement membrane components with fluorescent proteins, C. elegans has facilitated novel insights into the assembly and function of basement membranes. Although basement membranes are generally thought of as static structures, studies in C. elegans have revealed their active properties and essential functions in tissue formation and maintenance. Here, we review discoveries from C. elegans development that highlight dynamic aspects of basement membrane assembly, function, and regulation during organ growth, tissue polarity, cell migration, cell invasion, and tissue attachment. These studies have helped transform our view of basement membranes from static support structures to dynamic scaffoldings that play broad roles in regulating tissue organization and cellular behavior that are essential for development and have important implications in human diseases.
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13
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Morrissey MA, Sherwood DR. An active role for basement membrane assembly and modification in tissue sculpting. J Cell Sci 2015; 128:1661-8. [PMID: 25717004 DOI: 10.1242/jcs.168021] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Basement membranes are a dense, sheet-like form of extracellular matrix (ECM) that underlie epithelia and endothelia, and surround muscle, fat and Schwann cells. Basement membranes separate tissues and protect them from mechanical stress. Although traditionally thought of as a static support structure, a growing body of evidence suggests that dynamic basement membrane deposition and modification instructs coordinated cellular behaviors and acts mechanically to sculpt tissues. In this Commentary, we highlight recent studies that support the idea that far from being a passive matrix, basement membranes play formative roles in shaping tissues.
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Affiliation(s)
- Meghan A Morrissey
- Department of Biology, Duke University, Science Drive, Box 90388, Durham, NC 27708, USA
| | - David R Sherwood
- Department of Biology, Duke University, Science Drive, Box 90388, Durham, NC 27708, USA
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14
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B-LINK: a hemicentin, plakin, and integrin-dependent adhesion system that links tissues by connecting adjacent basement membranes. Dev Cell 2014; 31:319-331. [PMID: 25443298 DOI: 10.1016/j.devcel.2014.08.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/15/2014] [Accepted: 08/27/2014] [Indexed: 01/08/2023]
Abstract
Basement membrane (BM), a sheet-like form of extracellular matrix, surrounds most tissues. During organogenesis, specific adhesions between adjoining tissues frequently occur; however, their molecular basis is unclear. Using live-cell imaging and electron microscopy, we identify an adhesion system that connects the uterine and gonadal tissues through their juxtaposed BMs at the site of anchor cell (AC) invasion in C. elegans. We find that the extracellular matrix component hemicentin (HIM-4), found between BMs, forms punctate accumulations under the AC and controls BM linkage to promote rapid invasion. Through targeted screening, we identify the integrin-binding cytolinker plakin (VAB-10A) and integrin (INA-1/PAT-3) as key BM-BM linkage regulators: VAB-10A localizes to the AC-BM interface and tethers hemicentin to the AC while integrin promotes hemicentin punctae formation. Together, plakin, integrin, and hemicentin are founding components of a cell-directed adhesion system, which we name a BM-LINKage (B-LINK), that connects adjacent tissues through adjoining BMs.
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Kelberman D, Islam L, Lakowski J, Bacchelli C, Chanudet E, Lescai F, Patel A, Stupka E, Buck A, Wolf S, Beales PL, Jacques TS, Bitner-Glindzicz M, Liasis A, Lehmann OJ, Kohlhase J, Nischal KK, Sowden JC. Mutation of SALL2 causes recessive ocular coloboma in humans and mice. Hum Mol Genet 2014; 23:2511-26. [PMID: 24412933 PMCID: PMC3990155 DOI: 10.1093/hmg/ddt643] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ocular coloboma is a congenital defect resulting from failure of normal closure of the optic fissure during embryonic eye development. This birth defect causes childhood blindness worldwide, yet the genetic etiology is poorly understood. Here, we identified a novel homozygous mutation in the SALL2 gene in members of a consanguineous family affected with non-syndromic ocular coloboma variably affecting the iris and retina. This mutation, c.85G>T, introduces a premature termination codon (p.Glu29*) predicted to truncate the SALL2 protein so that it lacks three clusters of zinc-finger motifs that are essential for DNA-binding activity. This discovery identifies SALL2 as the third member of the Drosophila homeotic Spalt-like family of developmental transcription factor genes implicated in human disease. SALL2 is expressed in the developing human retina at the time of, and subsequent to, optic fissure closure. Analysis of Sall2-deficient mouse embryos revealed delayed apposition of the optic fissure margins and the persistence of an anterior retinal coloboma phenotype after birth. Sall2-deficient embryos displayed correct posterior closure toward the optic nerve head, and upon contact of the fissure margins, dissolution of the basal lamina occurred and PAX2, known to be critical for this process, was expressed normally. Anterior closure was disrupted with the fissure margins failing to meet, or in some cases misaligning leading to a retinal lesion. These observations demonstrate, for the first time, a role for SALL2 in eye morphogenesis and that loss of function of the gene causes ocular coloboma in humans and mice.
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Ramadhani D, Tsukada T, Fujiwara K, Horiguchi K, Kikuchi M, Yashiro T. Laminin isoforms and laminin-producing cells in rat anterior pituitary. Acta Histochem Cytochem 2012; 45:309-15. [PMID: 23209340 PMCID: PMC3499700 DOI: 10.1267/ahc.12028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 08/07/2012] [Indexed: 12/31/2022] Open
Abstract
Laminin is a key component of the basement membrane and is involved in the structural scaffold and in cell proliferation and differentiation. Research has identified 19 laminin isoforms, which are assemblies of α, β, and γ chains (eg, the α1, β1, and γ1 chains form the laminin 111 isoform). Although laminin is known to be present in the anterior pituitary, the specific laminin isoforms have not been identified. This study used molecular biological and histochemical techniques-namely, RT-PCR, immunohistochemistry, and in situ hybridization-to identify the laminin isoforms and laminin-producing cells in rat anterior pituitary. RT-PCR showed that laminin α1, α3, and α4 genes were expressed in anterior pituitary. Immunohistochemistry revealed laminin α1 in gonadotrophs and laminin α4 in almost all vascular endothelial cells. Laminin α3 was seen in a subset of vascular endothelial cells. We then performed in situ hybridization to localize β and γ chains in these cells and found that laminin β1, β2, and γ1 were expressed in gonadotrophs and that laminin β1 and γ1 were expressed in endothelial cells. In conclusion, we identified gonadotroph-type (laminin 111 and 121) and vascular-type (laminin 411 and 311) laminin isoforms in rat anterior pituitary.
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Affiliation(s)
- Dini Ramadhani
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
| | - Takehiro Tsukada
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
| | - Ken Fujiwara
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
| | - Kotaro Horiguchi
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
| | - Motoshi Kikuchi
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
| | - Takashi Yashiro
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine
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