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Cheng C. Tissue, cellular, and molecular level determinants for eye lens stiffness and elasticity. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1456474. [PMID: 39176256 PMCID: PMC11339033 DOI: 10.3389/fopht.2024.1456474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Accepted: 07/26/2024] [Indexed: 08/24/2024]
Abstract
The eye lens is a transparent, ellipsoid tissue in the anterior chamber that is required for the fine focusing of light onto the retina to transmit a clear image. The focusing function of the lens is tied to tissue transparency, refractive index, and biomechanical properties. The stiffness and elasticity or resilience of the human lens allows for shape changes during accommodation to focus light from objects near and far. It has long been hypothesized that changes in lens biomechanical properties with age lead to the loss of accommodative ability and the need for reading glasses with age. However, the cellular and molecular mechanisms that influence lens biomechanical properties and/or change with age remain unclear. Studies of lens stiffness and resilience in mouse models with genetic defects or at advanced age inform us of the cytoskeletal, structural, and morphometric parameters that are important for biomechanical stability. In this review, we will explore whether: 1) tissue level changes, including the capsule, lens volume, and nucleus volume, 2) cellular level alterations, including cell packing, suture organization, and complex membrane interdigitations, and 3) molecular scale modifications, including the F-actin and intermediate filament networks, protein modifications, lipids in the cell membrane, and hydrostatic pressure, influence overall lens biomechanical properties.
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Affiliation(s)
- Catherine Cheng
- School of Optometry and Vision Science Program, Indiana University, Bloomington, IN, United States
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2
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Zhang JJ, Cao ZF, Zhou BT, Yang JH, Li Z, Lin S, Chen XL, Zhang NW, Ye Q, Ma X, Zhu YH. Abnormal function of EPHA2/p.R957P mutant in congenital cataract. Int J Ophthalmol 2024; 17:1007-1017. [PMID: 38895685 PMCID: PMC11144770 DOI: 10.18240/ijo.2024.06.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/18/2024] [Indexed: 06/21/2024] Open
Abstract
AIM To identify genetic defects in a Chinese family with congenital posterior polar cataracts and assess the pathogenicity. METHODS A four-generation Chinese family affected with autosomal dominant congenital cataract was recruited. Nineteen individuals took part in this study including 5 affected and 14 unaffected individuals. Sanger sequencing targeted hot-spot regions of 27 congenital cataract-causing genes for variant discovery. The pathogenicity of the variant was evaluated by the guidelines of American College of Medical Genetics and InterVar software. Confocal microscopy was applied to detect the subcellular localization of fluorescence-labeled ephrin type-A receptor 2 (EPHA2). Co-immunoprecipitation assay was implemented to estimate the interaction between EphA2 and other lens membrane proteins. The mRNA and protein expression were analyzed by reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting assay, respectively. The cell migration was analyzed by wound healing assay. Zebrafish model was generated by ectopic expression of human EPHA2/p.R957P mutant to demonstrate whether the mutant could cause lens opacity in vivo. RESULTS A novel missense and pathogenic variant c.2870G>C was identified in the sterile alpha motif (SAM) domain of EPHA2. Functional studies demonstrated the variant's impact: reduced EPHA2 protein expression, altered subcellular localization, and disrupted interactions with other lens membrane proteins. This mutant notably enhanced human lens epithelial cell migration, and induced a central cloudy region and roughness in zebrafish lenses with ectopic expression of human EPHA2/p.R957P mutant under differential interference contrast (DIC) optics. CONCLUSION Novel pathogenic c.2870G>C variant of EPHA2 in a Chinese congenital cataract family contributes to disease pathogenesis.
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Affiliation(s)
- Jing-Jin Zhang
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University; Fujian Institute of Ophthalmology; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, Fuzhou 350005, Fujian Province, China
- Department of Ophthalmology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Zong-Fu Cao
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100000, China
- National Human Genetic Resources Center, National Research Institute for Family Planning, Beijing 100081, China
| | - Bi-Ting Zhou
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University; Fujian Institute of Ophthalmology; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, Fuzhou 350005, Fujian Province, China
- Department of Ophthalmology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Ju-Hua Yang
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University; Fujian Institute of Ophthalmology; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, Fuzhou 350005, Fujian Province, China
- Department of Ophthalmology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
- Department of Bioengineering and Biopharmaceutics, School of Pharmacy, Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Zhong Li
- Department of Bioengineering and Biopharmaceutics, School of Pharmacy, Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Shuang Lin
- Department of Bioengineering and Biopharmaceutics, School of Pharmacy, Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Xiao-Le Chen
- Department of Bioengineering and Biopharmaceutics, School of Pharmacy, Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Nan-Wen Zhang
- Department of Bioengineering and Biopharmaceutics, School of Pharmacy, Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Qin Ye
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University; Fujian Institute of Ophthalmology; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, Fuzhou 350005, Fujian Province, China
- Department of Ophthalmology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Xu Ma
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100000, China
- National Human Genetic Resources Center, National Research Institute for Family Planning, Beijing 100081, China
| | - Yi-Hua Zhu
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University; Fujian Institute of Ophthalmology; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, Fuzhou 350005, Fujian Province, China
- Department of Ophthalmology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
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Huynh PN, Cheng C. Spatial-temporal comparison of Eph/Ephrin gene expression in ocular lenses from aging and knockout mice. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1410860. [PMID: 38984128 PMCID: PMC11182306 DOI: 10.3389/fopht.2024.1410860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/06/2024] [Indexed: 07/11/2024]
Abstract
Cataracts, defined as any opacity in the transparent ocular lens, remain the leading cause of blindness and visual impairment in the world; however, the etiology of this pathology is not fully understood. Studies in mice and humans have found that the EphA2 receptor and the ephrin-A5 ligand play important roles in maintaining lens homeostasis and transparency. However, due to the diversity of the family of Eph receptors and ephrin ligands and their promiscuous binding, identifying functional interacting partners remains a challenge. Previously, 12 of the 14 Ephs and 8 of 8 ephrins in mice were characterized to be expressed in the mouse lens. To further narrow down possible genes of interest in life-long lens homeostasis, we collected and separated the lens epithelium from the fiber cell mass and isolated RNA from each compartment in samples from young adult and middle-aged mice that were either wild-type, EphA2-/- (knockout), or ephrin-A5 -/- . Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was implemented to compare transcript levels of 33 Eph and ephrin gene variants in each tissue compartment. Our results show that, of the Eph and ephrin variants screened, 5 of 33 showed age-related changes, and 2 of 33 showed genotype-related changes in lens epithelium. In the isolated fibers, more dynamic gene expression changes were observed, in which 12 of 33 variants showed age-related changes, and 6 of 33 showed genotype-related changes. These data allow for a more informed decision in determining mechanistic leads in Eph-ephrin-mediated signaling in the lens.
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Affiliation(s)
- Peter N Huynh
- School of Optometry and Vision Science Program, Indiana University, Bloomington, IN, United States
| | - Catherine Cheng
- School of Optometry and Vision Science Program, Indiana University, Bloomington, IN, United States
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Tan Y, Jiang W, Hu LY, Shen YY, Chen H, Zou YS, Luo LX, Jin GM, Liu ZZ. Hotspots and frontiers of genetic research on pediatric cataracts from 2013 to 2022: a scientometric analysis. Int J Ophthalmol 2023; 16:1682-1691. [PMID: 37854365 PMCID: PMC10559021 DOI: 10.18240/ijo.2023.10.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 08/02/2023] [Indexed: 10/20/2023] Open
Abstract
AIM To explore the hotspots and frontiers of genetic research on pediatric cataracts. METHODS Global publications from 2013 to 2022 related to genes in pediatric cataracts were extracted from the Web of Science Core Collection, and were analyzed in terms of the publication counts, countries, journals, authors, keywords, cited references, subject categories, and the underlying hotspots and frontiers. RESULTS Totally 699 publications were included in the final analysis. The predominant actors were identified, with China (n=240) and PLoS One (n=33) being the most productive country and journal respectively. The research hotspots extracted from keywords were crystallin gene mutations, pathogenicity evaluation, phenotypes of ocular and neurodevelopmental abnormalities, genes encoding membrane proteins, and diagnosis of multisystemic disorders. The co-cited articles formed 10 clusters of research topics, including FYCO1 (56 items), mutation screening (43 items), gap junction (29 items), the Warburg Micro syndrome (29 items), ephrin-A5 (28 items), novel mutation (24 items), eye development and function (22 items), cholestanol (7 items), OCRL (6 items), and pathogenicity prediction (3 items). The research frontiers were FYCO1, ephrin-A5, and cholestanol. Cell biology showed the strongest bridging effects among different disciplines in the field (betweenness centrality=0.44). CONCLUSION With the progress in next-generation sequencing and multidisciplinary collaboration, genetic research on pediatric cataracts broadens the knowledge scope of the crystalline lens, as well as other organs and systems, shedding light on the molecular mechanisms of systemic diseases. Cell biology may integrate multidisciplinary content to address cutting-edge issues in the field.
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Affiliation(s)
- Yuan Tan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
| | - Wei Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
- Zhongshan Medical School, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Le-Yi Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
| | - Yan-Yu Shen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
| | - Hui Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
| | - Ying-Shi Zou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
| | - Li-Xia Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
| | - Guang-Ming Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
| | - Zhen-Zhen Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, Guangdong Province, China
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Islam ST, Cheng C, Parreno J, Fowler VM. Nonmuscle Myosin IIA Regulates the Precise Alignment of Hexagonal Eye Lens Epithelial Cells During Fiber Cell Formation and Differentiation. Invest Ophthalmol Vis Sci 2023; 64:20. [PMID: 37070941 PMCID: PMC10123325 DOI: 10.1167/iovs.64.4.20] [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: 10/21/2022] [Accepted: 03/27/2023] [Indexed: 04/19/2023] Open
Abstract
Purpose Epithelial cells in the equatorial region of the ocular lens undergo a remarkable transition from randomly packed cells into precisely aligned and hexagon-shaped cells organized into meridional rows. We investigated the function of nonmuscle myosin IIA (encoded by Myh9) in regulating equatorial epithelial cell alignment to form meridional rows during secondary fiber cell morphogenesis. Methods We used genetic knock-in mice to study a common human Myh9 mutation, E1841K, in the rod domain. The E1841K mutation disrupts bipolar filament assembly. Lens shape, clarity, and stiffness were evaluated, and Western blots were used to determine the level of normal and mutant myosins. Cryosections and lens whole mounts were stained and imaged by confocal microscopy to investigate cell shape and organization. Results We observed no obvious changes in lens size, shape, and biomechanical properties (stiffness and resilience) between the control and nonmuscle myosin IIA-E1841K mutant mice at 2 months of age. Surprisingly, we found misalignment and disorder of fiber cells in heterozygous and homozygous mutant lenses. Further analysis revealed misshapen equatorial epithelial cells that cause disorientation of the meridional rows before fiber cell differentiation in homozygous mutant lenses. Conclusions Our data indicate that nonmuscle myosin IIA bipolar filament assembly is required for the precise alignment of the meridional rows at the lens equator and that the organization of lens fiber cells depends on the proper patterning of meridional row epithelial cells. These data also suggest that lens fiber cell organization and a hexagonal shape are not required for normal lens size, shape transparency, or biomechanical properties.
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Affiliation(s)
- Sadia T. Islam
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States
| | - Catherine Cheng
- School of Optometry and Vision Science Program, Indiana University, Bloomington, Indiana, United States
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States
| | - Justin Parreno
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States
| | - Velia M. Fowler
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States
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6
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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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7
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Paidi SK, Zhang Q, Yang Y, Xia CH, Ji N, Gong X. Adaptive optical two-photon fluorescence microscopy probes cellular organization of ocular lenses in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.17.524320. [PMID: 36711806 PMCID: PMC9882239 DOI: 10.1101/2023.01.17.524320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The mammalian ocular lens is an avascular multicellular organ that grows continuously throughout life. Traditionally, its cellular organization is investigated using dissected lenses, which eliminates in vivo environmental and structural support. Here, we demonstrated that two-photon fluorescence microscopy (2PFM) can visualize lens cells in vivo. To maintain subcellular resolution at depth, we employed adaptive optics (AO) to correct aberrations due to ocular and lens tissues, which led to substantial signal and resolution improvements. Imaging lens cells up to 980 μm deep, we observed novel cellular organizations including suture-associated voids, enlarged vacuoles, and large cavities, contrary to the conventional view of a highly ordered organization. We tracked these features longitudinally over weeks and observed the incorporation of new cells during growth. Taken together, non-invasive longitudinal in vivo imaging of lens morphology using AO 2PFM will allow us to directly observe the development or alterations of lens cellular organization in living animals.
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Affiliation(s)
- Santosh Kumar Paidi
- School of Optometry, University of California, Berkeley, California 94720, USA
| | - Qinrong Zhang
- Department of Physics, University of California, Berkeley, California 94720, USA,Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Yuhan Yang
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Chun-Hong Xia
- School of Optometry, University of California, Berkeley, California 94720, USA,Vision Science Program, University of California, Berkeley, California 94720, USA
| | - Na Ji
- Department of Physics, University of California, Berkeley, California 94720, USA,Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA,Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA,Corresponding authors: Xiaohua Gong () and Na Ji ()
| | - Xiaohua Gong
- School of Optometry, University of California, Berkeley, California 94720, USA,Vision Science Program, University of California, Berkeley, California 94720, USA,Corresponding authors: Xiaohua Gong () and Na Ji ()
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Mapping the Universe of Eph Receptor and Ephrin Ligand Transcripts in Epithelial and Fiber Cells of the Eye Lens. Cells 2022; 11:cells11203291. [PMID: 36291158 PMCID: PMC9600312 DOI: 10.3390/cells11203291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/17/2022] Open
Abstract
The eye lens is a transparent, ellipsoid organ in the anterior chamber of the eye that is required for fine focusing of light onto the retina to transmit a clear image. Cataracts, defined as any opacity in the lens, remains the leading cause of blindness in the world. Recent studies in humans and mice indicate that Eph–ephrin bidirectional signaling is important for maintaining lens transparency. Specifically, mutations and polymorphisms in the EphA2 receptor and the ephrin-A5 ligand have been linked to congenital and age-related cataracts. It is unclear what other variants of Ephs and ephrins are expressed in the lens or whether there is preferential expression in epithelial vs. fiber cells. We performed a detailed analysis of Eph receptor and ephrin ligand mRNA transcripts in whole mouse lenses, epithelial cell fractions, and fiber cell fractions using a new RNA isolation method. We compared control samples with EphA2 knockout (KO) and ephrin-A5 KO samples. Our results revealed the presence of transcripts for 12 out of 14 Eph receptors and 8 out of 8 ephrin ligands in various fractions of lens cells. Using specific primer sets, RT-PCR, and sequencing, we verified the variant of each gene that is expressed, and we found two epithelial-cell-specific genes. Surprisingly, we also identified one Eph receptor variant that is expressed in KO lens fibers but is absent from control lens fibers. We also identified one low expression ephrin variant that is only expressed in ephrin-A5 control samples. These results indicate that the lens expresses almost all Ephs and ephrins, and there may be many receptor–ligand pairs that play a role in lens homeostasis.
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Parreno J, Emin G, Vu MP, Clark JT, Aryal S, Patel SD, Cheng C. Methodologies to unlock the molecular expression and cellular structure of ocular lens epithelial cells. Front Cell Dev Biol 2022; 10:983178. [PMID: 36176273 PMCID: PMC9514789 DOI: 10.3389/fcell.2022.983178] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/16/2022] [Indexed: 01/25/2023] Open
Abstract
The transparent ocular lens in the anterior chamber of the eye is responsible for fine focusing of light onto the retina. The lens is entirely cellular with bulk of the tissue composed of fiber cells, and the anterior hemisphere of the lens is covered by a monolayer of epithelial cells. Lens epithelial cells are important for maintaining fiber cell homeostasis and for continual growth of the lens tissue throughout life. Cataracts, defined as any opacity in the lens, remain the leading cause of blindness in the world. Following cataract surgery, lens epithelial cells can undergo a process of epithelial-to-mesenchymal transition (EMT), leading to secondary cataracts due to posterior capsular opacification (PCO). Since the epithelial cells make up only a small fraction of the lens, specialized techniques are required to study lens epithelial cell biology and pathology. Studies using native lens epithelial cells often require pooling of samples to obtain enough cells to make sufficient samples for traditional molecular biology techniques. Here, we provide detailed protocols that enable the study of native mouse lens epithelial cells, including immunostaining of the native lens epithelium in flat mounts, extraction of RNA and proteins from pairs of lens epithelial monolayers, and isolation of lens epithelial cells for primary culture. These protocols will enable researchers to gain better insight on representative molecular expression and cellular structure of lens epithelial cells. We also provide comparative data between native, primary culture, and immortalized lens epithelial cells and discuss the advantages and disadvantages of each technique presented.
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Affiliation(s)
- Justin Parreno
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
- *Correspondence: Justin Parreno, ; Catherine Cheng,
| | - Grace Emin
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Michael P. Vu
- School of Optometry and Vision Science Program, Indiana University, Bloomington, IN, United States
| | - Jackson T. Clark
- School of Optometry and Vision Science Program, Indiana University, Bloomington, IN, United States
| | - Sandeep Aryal
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Shaili D. Patel
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Catherine Cheng
- School of Optometry and Vision Science Program, Indiana University, Bloomington, IN, United States
- *Correspondence: Justin Parreno, ; Catherine Cheng,
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Beyer EC, Mathias RT, Berthoud VM. Loss of fiber cell communication may contribute to the development of cataracts of many different etiologies. Front Physiol 2022; 13:989524. [PMID: 36171977 PMCID: PMC9511111 DOI: 10.3389/fphys.2022.989524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
The lens is an avascular organ that is supported by an internal circulation of water and solutes. This circulation is driven by ion pumps, channels and transporters in epithelial cells and by ion channels in fiber cells and is maintained by fiber-fiber and fiber-epithelial cell communication. Gap junctional intercellular channels formed of connexin46 and connexin50 are critical components of this circulation as demonstrated by studies of connexin null mice and connexin mutant mice. Moreover, connexin mutants are one of the most common causes of autosomal dominant congenital cataracts. However, alterations of the lens circulation and coupling between lens fiber cells are much more prevalent, beyond the connexin mutant lenses. Intercellular coupling and levels of connexins are decreased with aging. Gap junction-mediated intercellular communication decreases in mice expressing mutant forms of several different lens proteins and in some mouse models of lens protein damage. These observations suggest that disruption of ionic homeostasis due to reduction of the lens circulation is a common component of the development of many different types of cataracts. The decrease in the lens circulation often reflects low levels of lens fiber cell connexins and/or functional gap junction channels.
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Affiliation(s)
- Eric C. Beyer
- Department of Pediatrics, University of Chicago, Chicago, IL, United States
- *Correspondence: Eric C. Beyer,
| | - Richard T. Mathias
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, United States
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Patel SD, Anand D, Motohashi H, Katsuoka F, Yamamoto M, Lachke SA. Deficiency of the bZIP transcription factors Mafg and Mafk causes misexpression of genes in distinct pathways and results in lens embryonic developmental defects. Front Cell Dev Biol 2022; 10:981893. [PMID: 36092713 PMCID: PMC9459095 DOI: 10.3389/fcell.2022.981893] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/28/2022] [Indexed: 01/11/2023] Open
Abstract
Deficiency of the small Maf proteins Mafg and Mafk cause multiple defects, namely, progressive neuronal degeneration, cataract, thrombocytopenia and mid-gestational/perinatal lethality. Previous data shows Mafg -/-:Mafk +/- compound knockout (KO) mice exhibit cataracts age 4-months onward. Strikingly, Mafg -/-:Mafk -/- double KO mice develop lens defects significantly early in life, during embryogenesis, but the pathobiology of these defects is unknown, and is addressed here. At embryonic day (E)16.5, the epithelium of lens in Mafg -/-:Mafk -/- animals appears abnormally multilayered as demonstrated by E-cadherin and nuclear staining. Additionally, Mafg -/-:Mafk -/- lenses exhibit abnormal distribution of F-actin near the "fulcrum" region where epithelial cells undergo apical constriction prior to elongation and reorientation as early differentiating fiber cells. To identify the underlying molecular changes, we performed high-throughput RNA-sequencing of E16.5 Mafg -/-:Mafk -/- lenses and identified a cohort of differentially expressed genes that were further prioritized using stringent filtering criteria and validated by RT-qPCR. Several key factors associated with the cytoskeleton, cell cycle or extracellular matrix (e.g., Cdk1, Cdkn1c, Camsap1, Col3a1, Map3k12, Sipa1l1) were mis-expressed in Mafg -/-:Mafk -/- lenses. Further, the congenital cataract-linked extracellular matrix peroxidase Pxdn was significantly overexpressed in Mafg -/-:Mafk -/- lenses, which may cause abnormal cell morphology. These data also identified the ephrin signaling receptor Epha5 to be reduced in Mafg -/-:Mafk -/- lenses. This likely contributes to the Mafg -/-:Mafk -/- multilayered lens epithelium pathology, as loss of an ephrin ligand, Efna5 (ephrin-A5), causes similar lens defects. Together, these findings uncover a novel early function of Mafg and Mafk in lens development and identify their new downstream regulatory relationships with key cellular factors.
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Affiliation(s)
- Shaili D. Patel
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Deepti Anand
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Hozumi Motohashi
- Department of Gene Expression Regulation, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Fumiki Katsuoka
- Department of Integrative Genomics, Tohoku University Tohoku Medical Megabank Organization, Sendai, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Salil A. Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, United States,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States,*Correspondence: Salil A. Lachke,
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12
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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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13
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Cheng C, Wang K, Hoshino M, Uesugi K, Yagi N, Pierscionek B. EphA2 Affects Development of the Eye Lens Nucleus and the Gradient of Refractive Index. Invest Ophthalmol Vis Sci 2022; 63:2. [PMID: 34978559 PMCID: PMC8742528 DOI: 10.1167/iovs.63.1.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Purpose Our studies in mouse eye lenses demonstrate that ephrin-A5 and EphA2 are needed for normal epithelial cells and lens transparency. We sought to determine whether EphA2 and ephrin-A5 are important for lens morphometrics, nucleus formation, and refractive index. Methods We performed tissue morphometric measurements, electron microscopy, Western blots, and interferometric measurements using an X-ray synchrotron beam source to measure the gradient of refractive index (GRIN) to compare mouse lenses with genetic disruption of EphA2 or ephrin-A5. Results Morphometric analysis revealed that although there is no change in the overall lens volume, there is a change in lens shape in both EphA2-/- lenses and ephrin-A5-/- lenses. Surprisingly, EphA2-/- lenses had small and soft lens nuclei different from hard lens nuclei of control lenses. SEM images revealed changes in cell morphology of EphA2-/- fiber cells close to the center of the lens. Inner EphA2-/- lens fibers had more pronounced tongue-and-groove interdigitations and formed globular membrane morphology only in the deepest layers of the lens nucleus. We did not observe nuclear defects in ephrin-A5-/- lenses. There was an overall decrease in magnitude of refractive index across EphA2-/- lenses, which is most pronounced in the nucleus. Conclusions This work reveals that Eph-ephrin signaling plays a role in fiber cell maturation, nuclear compaction, and lens shape. Loss of EphA2 disrupts the nuclear compaction resulting in a small lens nucleus. Our data suggest that Eph-ephrin signaling may be required for fiber cell membrane reorganization and compaction and for establishing a normal GRIN.
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Affiliation(s)
- Catherine Cheng
- School of Optometry, Indiana University, Bloomington, IN, United States
| | - Kehao Wang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Engineering Medicine, Beihang University, Beijing, China
| | - Masato Hoshino
- Japan Synchrotron Radiation Research Institute (Spring-8), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 Japan
| | - Kentaro Uesugi
- Japan Synchrotron Radiation Research Institute (Spring-8), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 Japan
| | - Naoto Yagi
- Japan Synchrotron Radiation Research Institute (Spring-8), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 Japan
| | - Barbara Pierscionek
- Faculty of Health, Education, Medicine and Social Care, Medical Technology Research Centre, Anglia Ruskin University, Chelmsford Campus, United Kingdom
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14
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Cheng C, Gao J, Sun X, Mathias RT. Eph-ephrin Signaling Affects Eye Lens Fiber Cell Intracellular Voltage and Membrane Conductance. Front Physiol 2021; 12:772276. [PMID: 34899394 PMCID: PMC8656704 DOI: 10.3389/fphys.2021.772276] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/27/2021] [Indexed: 01/07/2023] Open
Abstract
The avascular eye lens generates its own microcirculation that is required for maintaining lifelong lens transparency. The microcirculation relies on sodium ion flux, an extensive network of gap junction (GJ) plaques between lens fiber cells and transmembrane water channels. Disruption of connexin proteins, the building blocks of GJs, or aquaporins, which make up water and adhesion channels, lead to lens opacification or cataracts. Recent studies have revealed that disruption of Eph-ephrin signaling, in particular the receptor EphA2 and the ligand ephrin-A5, in humans and mice lead to congenital and age-related cataracts. We investigated whether changes in lens transparency in EphA2 or ephrin-A5 knockout (–/–) mice is related to changes in GJ coupling and lens fluid and ion homeostasis. Immunostaining revealed changes in connexin 50 (Cx50) subcellular localization in EphA2–/– peripheral lens fibers and alteration in aquaporin 0 (Aqp0) staining patterns in ephrin-A5–/– and EphA2–/– inner mature fiber cells. Surprisingly, there was no obvious change in GJ coupling in knockout lenses. However, there were changes in fiber cell membrane conductance and intracellular voltage in knockout lenses from 3-month-old mice. These knockout lenses displayed decreased conductance of mature fiber membranes and were hyperpolarized compared to control lenses. This is the first demonstration that the membrane conductance of lens fibers can be regulated. Together these data suggest that EphA2 may be needed for normal Cx50 localization to the cell membrane and that conductance of lens fiber cells requires normal Eph-ephrin signaling and water channel localization.
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Affiliation(s)
- Catherine Cheng
- School of Optometry and Vision Science Program, Indiana University, Bloomington, IN, United States
| | - Junyuan Gao
- Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, NY, United States
| | - Xiurong Sun
- Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, NY, United States
| | - Richard T Mathias
- Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, NY, United States
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15
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Cheng C. EphA2 and Ephrin-A5 Guide Eye Lens Suture Alignment and Influence Whole Lens Resilience. Invest Ophthalmol Vis Sci 2021; 62:3. [PMID: 34854885 PMCID: PMC8648058 DOI: 10.1167/iovs.62.15.3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Fine focusing of light by the eye lens onto the retina relies on the ability of the lens to change shape during the process of accommodation. Little is known about the cellular structures that regulate elasticity and resilience. We tested whether Eph–ephrin signaling is involved in lens biomechanical properties. Methods We used confocal microscopy and tissue mechanical testing to examine mouse lenses with genetic disruption of EphA2 or ephrin-A5. Results Confocal imaging revealed misalignment of the suture between each shell of newly added fiber cells in knockout lenses. Despite having disordered sutures, loss of EphA2 or ephrin-A5 did not affect lens stiffness. Surprisingly, knockout lenses were more resilient and recovered almost completely after load removal. Confocal microscopy and quantitative image analysis from live lenses before, during, and after compression revealed that knockout lenses had misaligned Y-sutures, leading to a change in force distribution during compression. Knockout lenses displayed decreased separation of fiber cell tips at the anterior suture at high loads and had more complete recovery after load removal, which leads to improved whole-lens resiliency. Conclusions EphA2 and ephrin-A5 are needed for normal patterning of fiber cell tips and the formation of a well-aligned Y-suture with fiber tips stacked on top of previous generations of fiber cells. The misalignment of lens sutures leads to increased resilience after compression. The data suggest that alignment of the Y-suture may constrain the overall elasticity and resilience of the lens.
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Affiliation(s)
- Catherine Cheng
- School of Optometry and Vision Science Program, Indiana University, Bloomington, Indiana, United States
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16
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Wishart TFL, Lovicu FJ. An Atlas of Heparan Sulfate Proteoglycans in the Postnatal Rat Lens. Invest Ophthalmol Vis Sci 2021; 62:5. [PMID: 34730792 PMCID: PMC8572486 DOI: 10.1167/iovs.62.14.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose The arrangement of lens cells is regulated by ocular growth factors. Although the effects of these inductive molecules on lens cell behavior (proliferation, survival, and fiber differentiation) are well-characterized, the precise mechanisms underlying the regulation of growth factor-mediated signaling in lens remains elusive. Increasing evidence highlights the importance of heparan sulfate proteoglycans (HSPGs) for the signaling regulation of growth factors; however, the identity of the different lens HSPGs and the specific roles they play in lens biology are still unknown. Methods Semiquantitative real-time (RT)‐PCR and immunolabeling were used to characterize the spatial distribution of all known HSPG core proteins and their associated glycosaminoglycans (heparan and chondroitin sulfate) in the postnatal rat lens. Fibroblast growth factor (FGF)-2-treated lens epithelial explants, cultured in the presence of Surfen (an inhibitor of heparan sulfate [HS]-growth factor binding interactions) were used to investigate the requirement for HS in FGF-2-induced proliferation, fiber differentiation, and ERK1/2-signaling. Results The lens expresses all HSPGs. These HSPGs are differentially localized to distinct functional regions of the lens. In vitro, inhibition of HS-sulfation with Surfen blocked FGF-2-mediated ERK1/2-signaling associated with lens epithelial cell proliferation and fiber differentiation, highlighting that these cellular processes are dependent on HS. Conclusions These findings support a requirement for HSPGs in FGF-2 driven lens cell proliferation and fiber differentiation. The identification of specific HSPG core proteins in key functional lens regions, and the divergent expression patterns of closely related HSPGs, suggests that different HSPGs may differentially regulate growth factor signaling networks leading to specific biological events involved in lens growth and maintenance.
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Affiliation(s)
- Tayler F L Wishart
- School of Medical Sciences, The University of Sydney, New South Wales, Australia
| | - Frank J Lovicu
- School of Medical Sciences, The University of Sydney, New South Wales, Australia.,Save Sight Institute, The University of Sydney, New South Wales, Australia
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17
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Mutation of the EPHA2 Tyrosine-Kinase Domain Dysregulates Cell Pattern Formation and Cytoskeletal Gene Expression in the Lens. Cells 2021; 10:cells10102606. [PMID: 34685586 PMCID: PMC8534143 DOI: 10.3390/cells10102606] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/13/2022] Open
Abstract
Genetic variations in ephrin type-A receptor 2 (EPHA2) have been associated with inherited and age-related forms of cataract in humans. Here, we have characterized the eye lens phenotype and transcript profile of germline Epha2 knock-in mutant mice homozygous for either a missense variant associated with age-related cataract in humans (Epha2-Q722) or a novel insertion-deletion mutation (Epha2-indel722) that were both located within the tyrosine-kinase domain of EPHA2. Confocal imaging of ex vivo lenses from Epha2-indel722 mice on a fluorescent reporter background revealed misalignment of epithelial-to-fiber cell meridional-rows at the lens equator and severe disturbance of Y-suture formation at the lens poles, whereas Epha2-Q722 lenses displayed mild disturbance of posterior sutures. Immunofluorescent labeling showed that EPHA2 was localized to radial columns of hexagonal fiber cell membranes in Epha2-Q722 lenses, whereas Epha2-indel722 lenses displayed disorganized radial cell columns and cytoplasmic retention of EPHA2. Immunoprecipitation/blotting studies indicated that EPHA2 formed strong complexes with Src kinase and was mostly serine phosphorylated in the lens. RNA sequencing analysis revealed differential expression of several cytoskeleton-associated genes in Epha2-mutant and Epha2-null lenses including shared downregulation of Lgsn and Clic5. Collectively, our data suggest that mutations within the tyrosine-kinase domain of EPHA2 result in lens cell patterning defects and dysregulated expression of several cytoskeleton-associated proteins.
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18
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Dave A, Craig JE, Alamein M, Skrzypiec K, Beltz J, Pfaff A, Burdon KP, Ercal N, de Iongh RU, Sharma S. Genotype, Age, Genetic Background, and Sex Influence Epha2-Related Cataract Development in Mice. Invest Ophthalmol Vis Sci 2021; 62:3. [PMID: 34495288 PMCID: PMC8431977 DOI: 10.1167/iovs.62.12.3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose Age-related cataract is the leading cause of blindness worldwide. Variants in the EPHA2 gene increase the disease risk, and its knockout in mice causes cataract. We investigated whether age, sex, and genetic background, risk factors for age-related cataract, and Epha2 genotype influence Epha2-related cataract development in mice. Methods Cataract development was monitored in Epha2+/+, Epha2+/-, and Epha2-/- mice (Epha2Gt(KST085)Byg) on C57BL/6J and FVB:C57BL/6J (50:50) backgrounds. Cellular architecture of lenses, endoplasmic reticulum (ER) stress, and redox state were determined using histological, molecular, and analytical techniques. Results Epha2-/- and Epha2+/- mice on C57BL/6J background developed severe cortical cataracts by 18 and 38 weeks of age, respectively, compared to development of similar cataract significantly later in Epha2-/- mice and no cataract in Epha2+/- mice in this strain on FVB background, which was previously reported. On FVB:C57BL/6J background, Epha2-/- mice developed severe cortical cataract by 38 weeks and Epha2+/- mice exhibited mild cortical cataract up to 64 weeks of age. Progression of cataract in Epha2-/- and Epha2+/- female mice on C57BL/6J and mixed background, respectively, was slower than in matched male mice. N-cadherin and β-catenin immunolabeling showed disorganized lens fiber cells and disruption of lens architecture in Epha2-/- and Epha2+/- lenses, coinciding with development of severe cataracts. EPHA2 immunolabeling showed intracellular accumulation of the mutant EPHA2-β-galactosidase fusion protein that induced a cytoprotective ER stress response and in Epha2+/- lenses was also accompanied by glutathione redox imbalance. Conclusions Both, Epha2-/- and Epha2+/- mice develop age-related cortical cataract; age as a function of Epha2 genotype, sex, and genetic background influence Epha2-related cataractogenesis in mice.
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Affiliation(s)
- Alpana Dave
- Department of Ophthalmology, Flinders University, Bedford Park, South Australia, Australia
| | - Jamie E Craig
- Department of Ophthalmology, Flinders University, Bedford Park, South Australia, Australia
| | - Mohammad Alamein
- Department of Ophthalmology, Flinders University, Bedford Park, South Australia, Australia
| | - Karina Skrzypiec
- Department of Ophthalmology, Flinders University, Bedford Park, South Australia, Australia
| | - Justin Beltz
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri, United States
| | - Annalise Pfaff
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri, United States
| | - Kathryn P Burdon
- Department of Ophthalmology, Flinders University, Bedford Park, South Australia, Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Nuran Ercal
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri, United States
| | - Robb U de Iongh
- Ocular Development Laboratory, Anatomy & Neuroscience, University of Melbourne, Parkville, Australia
| | - Shiwani Sharma
- Department of Ophthalmology, Flinders University, Bedford Park, South Australia, Australia
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19
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Cheng C, Parreno J, Nowak RB, Biswas SK, Wang K, Hoshino M, Uesugi K, Yagi N, Moncaster JA, Lo WK, Pierscionek B, Fowler VM. Age-related changes in eye lens biomechanics, morphology, refractive index and transparency. Aging (Albany NY) 2019; 11:12497-12531. [PMID: 31844034 PMCID: PMC6949082 DOI: 10.18632/aging.102584] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/26/2019] [Indexed: 04/09/2023]
Abstract
Life-long eye lens function requires an appropriate gradient refractive index, biomechanical integrity and transparency. We conducted an extensive study of wild-type mouse lenses 1-30 months of age to define common age-related changes. Biomechanical testing and morphometrics revealed an increase in lens volume and stiffness with age. Lens capsule thickness and peripheral fiber cell widths increased between 2 to 4 months of age but not further, and thus, cannot account for significant age-dependent increases in lens stiffness after 4 months. In lenses from mice older than 12 months, we routinely observed cataracts due to changes in cell structure, with anterior cataracts due to incomplete suture closure and a cortical ring cataract corresponding to a zone of compaction in cortical lens fiber cells. Refractive index measurements showed a rapid growth in peak refractive index between 1 to 6 months of age, and the area of highest refractive index is correlated with increases in lens nucleus size with age. These data provide a comprehensive overview of age-related changes in murine lenses, including lens size, stiffness, nuclear fraction, refractive index, transparency, capsule thickness and cell structure. Our results suggest similarities between murine and primate lenses and provide a baseline for future lens aging studies.
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Affiliation(s)
- Catherine Cheng
- School of Optometry, Indiana University, Bloomington, IN 47405, USA
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Justin Parreno
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Roberta B. Nowak
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sondip K. Biswas
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA 30303, USA
| | - Kehao Wang
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Masato Hoshino
- Japan Synchrotron Radiation Research Institute (Spring-8), Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Kentaro Uesugi
- Japan Synchrotron Radiation Research Institute (Spring-8), Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Naoto Yagi
- Japan Synchrotron Radiation Research Institute (Spring-8), Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Juliet A. Moncaster
- Department of Radiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Woo-Kuen Lo
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA 30303, USA
| | - Barbara Pierscionek
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Velia M. Fowler
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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20
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Zhai Y, Zhu S, Li J, Yao K. A Novel Human Congenital Cataract Mutation in EPHA2 Kinase Domain (p.G668D) Alters Receptor Stability and Function. ACTA ACUST UNITED AC 2019; 60:4717-4726. [PMID: 31725171 DOI: 10.1167/iovs.19-27370] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Yi Zhai
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Eye Center, the Second Affiliated Hospital of the School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Sha Zhu
- Eye Center, the Second Affiliated Hospital of the School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jinyu Li
- Eye Center, the Second Affiliated Hospital of the School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Ke Yao
- Eye Center, the Second Affiliated Hospital of the School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
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21
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Plüss CJ, Kustermann S. A Human Three-Dimensional In Vitro Model of Lens Epithelial Cells as a Model to Study Mechanisms of Drug-Induced Posterior Subcapsular Cataracts. J Ocul Pharmacol Ther 2019; 36:56-64. [PMID: 31259661 DOI: 10.1089/jop.2019.0010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Purpose: Cataract is a pathological opacification of the lens, which is still one of the leading causes of blindness in the world. Several etiologies are described, among them drug-induced cataract, for example, posterior subcapsular cataract (PSC) after steroid treatment. To investigate different mechanisms of drug-induced cataract a human three-dimensional (3D) lens in vitro model was developed, consisting of immortalized human lens epithelial cells. Methods: These cells were cultivated on 96-well, ultralow attachment plates, where they rapidly form spheroids. By gene expression analysis different markers were observed, which are important to maintain lens transparency, such as ephrin type-A receptor 2 (EphA2) or α-smooth muscle actin (α-SMA). Results: The lens epithelial cells form a spheroid within a few days and show stable expression of important lens marker, and size and viability remain stable up to 26 days in culture. The gene expression of the glucocorticoid-treated spheroids revealed a clear shift in the expression of EphA2, α-SMA, αB-crystallin (CRYAB), and heat shock protein beta-1 (HSPB1). Furthermore, the glucocorticoid treatment did not improve cell survival. Conclusions: This study proposes a useful 3D in vitro model, which expresses important lens markers and is capable of demonstrating features found in drug-induced cataracts. As the viability remains stable over long time, this model can also be used for long-term treatment. The main characteristics are the increased expression of α-SMA, CRYAB, and HSPB1 and the decreased expression of EphA2. The present data provide some first evidence on novel mechanisms involved in glucocorticoid-induced cataracts.
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Affiliation(s)
- Carla Johanna Plüss
- Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Stefan Kustermann
- Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
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22
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Murcia Pienkowski V, Kucharczyk M, Młynek M, Szczałuba K, Rydzanicz M, Poszewiecka B, Skórka A, Sykulski M, Biernacka A, Koppolu AA, Posmyk R, Walczak A, Kosińska J, Krajewski P, Castaneda J, Obersztyn E, Jurkiewicz E, Śmigiel R, Gambin A, Chrzanowska K, Krajewska-Walasek M, Płoski R. Mapping of breakpoints in balanced chromosomal translocations by shallow whole-genome sequencing points to EFNA5, BAHD1 and PPP2R5E as novel candidates for genes causing human Mendelian disorders. J Med Genet 2018; 56:104-112. [PMID: 30352868 DOI: 10.1136/jmedgenet-2018-105527] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 09/21/2018] [Accepted: 09/22/2018] [Indexed: 11/04/2022]
Abstract
BACKGROUND Mapping the breakpoints in de novo balanced chromosomal translocations (BCT) in symptomatic individuals provides a unique opportunity to identify in an unbiased way the likely causative genetic defect and thus find novel human disease candidate genes. Our aim was to fine-map breakpoints of de novo BCTs in a case series of nine patients. METHODS Shallow whole-genome mate pair sequencing (SGMPS) together with long-range PCR and Sanger sequencing. In one case (BCT disrupting BAHD1 and RET) cDNA analysis was used to verify expression of a fusion transcript in cultured fibroblasts. RESULTS In all nine probands 11 disrupted genes were found, that is, EFNA5, EBF3, LARGE, PPP2R5E, TXNDC5, ZNF423, NIPBL, BAHD1, RET, TRPS1 and SLC4A10. Five subjects had translocations that disrupted genes with so far unknown (EFNA5, BAHD1, PPP2R5E, TXNDC5) or poorly delineated impact on the phenotype (SLC4A10, two previous reports of BCT disrupting the gene). The four genes with no previous disease associations (EFNA5, BAHD1, PPP2R5E, TXNDC5), when compared with all human genes by a bootstrap test, had significantly higher pLI (p<0.017) and DOMINO (p<0.02) scores indicating enrichment in genes likely to be intolerant to single copy damage. Inspection of individual pLI and DOMINO scores, and local topologically associating domain structure suggested that EFNA5, BAHD1 and PPP2R5E were particularly good candidates for novel disease loci. The pathomechanism for BAHD1 may involve deregulation of expression due to fusion with RET promoter. CONCLUSION SGMPS in symptomatic carriers of BCTs is a powerful approach to delineate novel human gene-disease associations.
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Affiliation(s)
- Victor Murcia Pienkowski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Marzena Kucharczyk
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Marlena Młynek
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Krzysztof Szczałuba
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | | | - Barbara Poszewiecka
- Faculty of Mathematics, Informatics and Mechanics, Institute of Informatics, University of Warsaw, Warsaw, Poland
| | - Agata Skórka
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland.,Department of Pediatrics, Medical University of Warsaw, Warsaw, Poland
| | - Maciej Sykulski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland.,genXone, Poznan, Poland
| | - Anna Biernacka
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Agnieszka Anna Koppolu
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Renata Posmyk
- Department of Clinical Genetics, Podlaskie Medical Center, Bialystok, Poland.,Department of Perinatology, Medical University of Bialystok, Bialystok, Poland
| | - Anna Walczak
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | - Joanna Kosińska
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | - Paweł Krajewski
- Department of Forensic Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Jennifer Castaneda
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Ewa Obersztyn
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Elżbieta Jurkiewicz
- Department of Diagnostic Imaging, The Children's Memorial Health Institute, Warsaw, Poland
| | - Robert Śmigiel
- Department of Pediatrics and Rare Disorder, Wroclaw Medical University, Wroclaw, Poland
| | - Anna Gambin
- Faculty of Mathematics, Informatics and Mechanics, Institute of Informatics, University of Warsaw, Warsaw, Poland
| | - Krystyna Chrzanowska
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
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23
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Zhou Y, Shiels A. Epha2 and Efna5 participate in lens cell pattern-formation. Differentiation 2018; 102:1-9. [PMID: 29800803 DOI: 10.1016/j.diff.2018.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 01/10/2023]
Abstract
Ephrin type-A receptor 2 (EPHA2) and one of its ligands, ephrin-A5 (EFNA5), have been associated with loss of eye lens transparency, or cataract, - an important cause of visual impairment. Here we show that mice functionally lacking EPHA2 (Epha2-null), EFNA5 (Efna5-null), or both receptor and ligand (Epha2/Efna5-null) consistently develop mostly transparent lenses with an internal refractive disturbance and a grossly disturbed cellular architecture. In situ hybridization localized Epha2 and Efna5 transcripts to lens epithelial cells and nascent fiber cells at the lens equator. In vivo labeling of Epha2-null lenses with a thymidine analog detected a significant decrease in lens epithelial cell proliferation within the germinative zone resulting in impaired early lens growth. Ex vivo imaging of Epha2-null, Efna5-null, and Epha2/Efna5-null lenses labelled in vivo with a membrane-targeted red fluorescent protein revealed misalignment of elongating fiber cells at the lens equator and loss of Y-suture pattern formation near the anterior and posterior poles of the lens. Immuno-fluorescent labeling of lens major intrinsic protein or aquaporin-0 (MIP/AQP0) showed that the precise, radial column patterning of hexagonal fiber cells throughout the cortex region was disrupted in Epha2-null, Efna5-null and Epha2/Efna5-null lenses. Collectively, these data suggest that Epha2 and Efna5 participate in the complex, global patterning of lens fiber cells that is necessary for maximal optical quality.
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Affiliation(s)
- Yuefang Zhou
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA.
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24
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Li Y, Jin L, Ye F, Ma Q, Yang Z, Liu D, Yang J, Ma D, Gao Q. Isoform expression patterns of EPHA10 protein mediate breast cancer progression by regulating the E-Cadherin and β-catenin complex. Oncotarget 2018; 8:30344-30356. [PMID: 28427223 PMCID: PMC5444747 DOI: 10.18632/oncotarget.15910] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 02/07/2017] [Indexed: 11/29/2022] Open
Abstract
Overexpression of EPHA10 protein was reported in concomitance with clinical severity of breast cancer. In this study, we annotate overexpression of EPHA10 protein with changes of isoform expression as EphA10s (EPHA10 isoform 2) and EphA10 (EPHA10 isoform 3). In the process of malignant transformation, secretory protein EphA10s is in low expression, and pseudo-kinase EphA10 is overexpressed and cytoplasmically enriched. Down-regulated EphA10s blunts stabilization of membrane-associate β-catenin via the interaction with ephrin A5. Cytoplasmic EphA10 maintains phosphorylation of E-cadherin. Restoring isoform expression pattern by up-regulated EphA10s and down-regulated cytoplasmic EphA10 inhibits cell invasion and lymph node metastasis by strengthening the stability of the complex of E-cadherin and β-catenin in membrane. Taken together, we defined the novel interaction via expression patterns of EphA10s and EphA10 that promote malignant transformation of breast cancer, and demonstrated the potential benefit in clinical usage.
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Affiliation(s)
- Ye Li
- Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.,Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Lu Jin
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Fei Ye
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Quanfu Ma
- Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zongyuan Yang
- Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Dan Liu
- Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jie Yang
- Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ding Ma
- Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Qinglei Gao
- Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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25
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Bennett TM, M’Hamdi O, Hejtmancik JF, Shiels A. Germ-line and somatic EPHA2 coding variants in lens aging and cataract. PLoS One 2017; 12:e0189881. [PMID: 29267365 PMCID: PMC5739433 DOI: 10.1371/journal.pone.0189881] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 12/04/2017] [Indexed: 11/18/2022] Open
Abstract
Rare germ-line mutations in the coding regions of the human EPHA2 gene (EPHA2) have been associated with inherited forms of pediatric cataract, whereas, frequent, non-coding, single nucleotide variants (SNVs) have been associated with age-related cataract. Here we sought to determine if germ-line EPHA2 coding SNVs were associated with age-related cataract in a case-control DNA panel (> 50 years) and if somatic EPHA2 coding SNVs were associated with lens aging and/or cataract in a post-mortem lens DNA panel (> 48 years). Micro-fluidic PCR amplification followed by targeted amplicon (exon) next-generation (deep) sequencing of EPHA2 (17-exons) afforded high read-depth coverage (1000x) for > 82% of reads in the cataract case-control panel (161 cases, 64 controls) and > 70% of reads in the post-mortem lens panel (35 clear lens pairs, 22 cataract lens pairs). Novel and reference (known) missense SNVs in EPHA2 that were predicted in silico to be functionally damaging were found in both cases and controls from the age-related cataract panel at variant allele frequencies (VAFs) consistent with germ-line transmission (VAF > 20%). Similarly, both novel and reference missense SNVs in EPHA2 were found in the post-mortem lens panel at VAFs consistent with a somatic origin (VAF > 3%). The majority of SNVs found in the cataract case-control panel and post-mortem lens panel were transitions and many occurred at di-pyrimidine sites that are susceptible to ultraviolet (UV) radiation induced mutation. These data suggest that novel germ-line (blood) and somatic (lens) coding SNVs in EPHA2 that are predicted to be functionally deleterious occur in adults over 50 years of age. However, both types of EPHA2 coding variants were present at comparable levels in individuals with or without age-related cataract making simple genotype-phenotype correlations inconclusive.
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Affiliation(s)
- Thomas M. Bennett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Oussama M’Hamdi
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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26
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Cvekl A, Zhang X. Signaling and Gene Regulatory Networks in Mammalian Lens Development. Trends Genet 2017; 33:677-702. [PMID: 28867048 DOI: 10.1016/j.tig.2017.08.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/27/2017] [Accepted: 08/01/2017] [Indexed: 11/16/2022]
Abstract
Ocular lens development represents an advantageous system in which to study regulatory mechanisms governing cell fate decisions, extracellular signaling, cell and tissue organization, and the underlying gene regulatory networks. Spatiotemporally regulated domains of BMP, FGF, and other signaling molecules in late gastrula-early neurula stage embryos generate the border region between the neural plate and non-neural ectoderm from which multiple cell types, including lens progenitor cells, emerge and undergo initial tissue formation. Extracellular signaling and DNA-binding transcription factors govern lens and optic cup morphogenesis. Pax6, c-Maf, Hsf4, Prox1, Sox1, and a few additional factors regulate the expression of the lens structural proteins, the crystallins. Extensive crosstalk between a diverse array of signaling pathways controls the complexity and order of lens morphogenetic processes and lens transparency.
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Affiliation(s)
- Ales Cvekl
- Departments of Genetics and Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Xin Zhang
- Departments of Ophthalmology, Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA.
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27
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Functional non-coding polymorphism in an EPHA2 promoter PAX2 binding site modifies expression and alters the MAPK and AKT pathways. Sci Rep 2017; 7:9992. [PMID: 28855599 PMCID: PMC5577203 DOI: 10.1038/s41598-017-10117-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/04/2017] [Indexed: 01/11/2023] Open
Abstract
To identify possible genetic variants influencing expression of EPHA2 (Ephrin-receptor Type-A2), a tyrosine kinase receptor that has been shown to be important for lens development and to contribute to both congenital and age related cataract when mutated, the extended promoter region of EPHA2 was screened for variants. SNP rs6603883 lies in a PAX2 binding site in the EPHA2 promoter region. The C (minor) allele decreased EPHA2 transcriptional activity relative to the T allele by reducing the binding affinity of PAX2. Knockdown of PAX2 in human lens epithelial (HLE) cells decreased endogenous expression of EPHA2. Whole RNA sequencing showed that extracellular matrix (ECM), MAPK-AKT signaling pathways and cytoskeleton related genes were dysregulated in EPHA2 knockdown HLE cells. Taken together, these results indicate a functional non-coding SNP in EPHA2 promoter affects PAX2 binding and reduces EPHA2 expression. They further suggest that decreasing EPHA2 levels alters MAPK, AKT signaling pathways and ECM and cytoskeletal genes in lens cells that could contribute to cataract. These results demonstrate a direct role for PAX2 in EPHA2 expression and help delineate the role of EPHA2 in development and homeostasis required for lens transparency.
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28
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Growth of hollow cell spheroids in microbead templated chambers. Biomaterials 2017; 143:57-64. [PMID: 28763630 DOI: 10.1016/j.biomaterials.2017.07.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/20/2017] [Accepted: 07/22/2017] [Indexed: 02/02/2023]
Abstract
Cells form hollow, spheroidal structures during the development of many tissues, including the ocular lens, inner ear, and many glands. Therefore, techniques for in vitro formation of hollow spheroids are valued for studying developmental and disease processes. Current in vitro methods require cells to self-organize into hollow morphologies; we explored an alternative strategy based on cell growth in predefined, spherical scaffolds. Our method uses sacrificial, gelatin microbeads to simultaneously template spherical chambers within a hydrogel and deliver cells into the chambers. We use mouse lens epithelial cells to demonstrate that cells can populate the internal surfaces of the chambers within a week to create numerous hollow spheroids. The platform supports manipulation of matrix mechanics, curvature, and biochemical composition to mimic in vivo microenvironments. It also provides a starting point for engineering organoids of tissues that develop from hollow spheroids.
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29
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Abstract
Eph-ephrin bidirectional signaling is essential for eye lens transparency in humans and mice. Our previous studies in mouse lenses demonstrate that ephrin-A5 is mainly expressed in the anterior epithelium, where it is required for maintaining the anterior epithelial monolayer. In contrast, EphA2 is localized in equatorial epithelial and fiber cells where it is essential for equatorial epithelial and fiber cell organization and hexagonal cell shape. Immunostaining of lens epithelial and fiber cells reveals that EphA2 and ephrin-A5 are also co-expressed in anterior fiber cell tips, equatorial epithelial cells and newly formed lens fibers, although they are not precisely colocalized. Due to this complex expression pattern and the promiscuous interactions between Eph receptors and ephrin ligands, as well as their complex bidirectional signaling pathways, cataracts in ephrin-A5(-/-) or EphA2(-/-) lenses may arise from loss of function or abnormal signaling mechanisms. To test whether abnormal signaling mechanisms may play a role in cataractogenesis in ephrin-A5(-/-) or EphA2(-/-) lenses, we generated EphA2 and ephrin-A5 double knockout (DKO) mice. We compared the phenotypes of EphA2(-/-) and ephrin-A5(-/-) lenses to that of DKO lenses. DKO lenses displayed an additive lens phenotype that was not significantly different from the two single KO lens phenotypes. Similar to ephrin-A5(-/-) lenses, DKO lenses had abnormal anterior epithelial cells leading to a large mass of epithelial cells that invade into the underlying fiber cell layer, directly resulting in anterior cataracts in ephrin-A5(-/-) and DKO lenses. Yet, similar to EphA2(-/-) lenses, DKO lenses also had abnormal packing of equatorial epithelial cells with disorganized meridional rows, lack of a lens fulcrum and disrupted fiber cells. The DKO lens phenotype rules out abnormal signaling by EphA2 in ephrin-A5(-/-) lenses or by ephrin-A5 in EphA2(-/-) lenses as possible cataract mechanisms. Thus, these results indicate that EphA2 and ephrin-A5 do not form a lens receptor-ligand pair, and that EphA2 and ephrin-A5 have other binding partners in the lens to help align differentiating equatorial epithelial cells or maintain the anterior epithelium, respectively.
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30
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Lv J, Wang Z, Wang Y, Sun W, Zhou J, Wang M, Liu WJ, Wang Y. Renoprotective Effect of the Shen-Yan-Fang-Shuai Formula by Inhibiting TNF- α/NF- κB Signaling Pathway in Diabetic Rats. J Diabetes Res 2017; 2017:4319057. [PMID: 28713834 PMCID: PMC5497613 DOI: 10.1155/2017/4319057] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/15/2016] [Indexed: 12/02/2022] Open
Abstract
Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, and satisfactory therapeutic strategies have not yet been established. The Shen-Yan-Fang-Shuai Formula (SYFSF) is a traditional Chinese formula composed of Astragali radix, Radixangelicae sinensis, Rheum officinale Baill, and four other herbs. It has been widely used as an effective treatment for DKD patients in China. However, little is known about the molecular mechanisms underlying SYFSF's renoprotection. In this study, we compared the protective effect of SYFSF to irbesartan on the histology and renal cells in type 2 DKD rat model and high-glucose (HG) cultured mesangial cells, respectively. We found that SYFSF could significantly decrease urinary albumin, cholesterol, and triglyceride. And a decrease in serum creatinine was also found in SYFSF-treated group compared with irbesartan-treated rats. In addition, SYFSF inhibited the interstitial expansion and glomerulosclerosis in diabetic rats. Notably, SYFSF markedly downregulated the expression of MCP-1, TGF-β1, collagen IV, and fibronectin in diabetic rat models and HG-induced mesangial cell models. The renoprotection was closely associated with a reduced expression of TNF-α and phosphorylated NF-κBp65. Our study suggests that SYFSF may ameliorate diabetic kidney injury. The observed renoprotection is probably attributable to an inhibition of inflammatory response and extracellular matrix (ECM) accumulation mediated by TNF-α/NF-κBp65 signaling pathway.
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Affiliation(s)
- Jie Lv
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
| | - Zhen Wang
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
| | - Ying Wang
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
| | - Weiwei Sun
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
| | - Jingwei Zhou
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
| | - Mengdi Wang
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
| | - Wei Jing Liu
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
- Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong 524001, China
| | - Yaoxian Wang
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Renal Research Institution, Beijing University of Chinese Medicine, Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100700, China
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Logan CM, Rajakaruna S, Bowen C, Radice GL, Robinson ML, Menko AS. N-cadherin regulates signaling mechanisms required for lens fiber cell elongation and lens morphogenesis. Dev Biol 2017; 428:118-134. [PMID: 28552735 DOI: 10.1016/j.ydbio.2017.05.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/15/2017] [Accepted: 05/15/2017] [Indexed: 12/14/2022]
Abstract
Tissue development and regeneration involve high-ordered morphogenetic processes that are governed by elements of the cytoskeleton in conjunction with cell adhesion molecules. Such processes are particularly important in the lens whose structure dictates its function. Studies of our lens-specific N-cadherin conditional knockout mouse (N-cadcKO) revealed an essential role for N-cadherin in the migration of the apical tips of differentiating lens fiber cells along the apical surfaces of the epithelium, a region termed the Epithelial Fiber Interface (EFI), that is necessary for normal fiber cell elongation and the morphogenesis. Studies of the N-cadcKO lens suggest that N-cadherin function in fiber cell morphogenesis is linked to the activation of Rac1 and myosin II, both signaling pathways central to the regulation of cell motility including determining the directionality of cellular movement. The absence of N-cadherin did not disrupt lateral contacts between fiber cells during development, and the maintenance of Aquaporin-0 and increased expression of EphA2 at cell-cell interfaces suggests that these molecules may function in this role. E-cadherin was maintained in newly differentiating fiber cells without interfering with expression of lens-specific differentiation proteins but was not able to replace N-cadherin function in these cells. The dependence of migration of the fiber cell apical domains along the EFI for lens morphogenesis on N-cadherin provides new insight into the process of tissue development.
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Affiliation(s)
- Caitlin M Logan
- Thomas Jefferson University, Pathology Anatomy and Cell Biology, Philadelphia, PA, United States
| | - Suren Rajakaruna
- Thomas Jefferson University, Pathology Anatomy and Cell Biology, Philadelphia, PA, United States
| | - Caitlin Bowen
- Thomas Jefferson University, Pathology Anatomy and Cell Biology, Philadelphia, PA, United States
| | - Glenn L Radice
- Thomas Jefferson University, Pathology Anatomy and Cell Biology, Philadelphia, PA, United States
| | - Michael L Robinson
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, United States
| | - A Sue Menko
- Thomas Jefferson University, Pathology Anatomy and Cell Biology, Philadelphia, PA, United States.
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Lee S, Shatadal S, Griep AE. Dlg-1 Interacts With and Regulates the Activities of Fibroblast Growth Factor Receptors and EphA2 in the Mouse Lens. Invest Ophthalmol Vis Sci 2016; 57:707-18. [PMID: 26906157 PMCID: PMC4771194 DOI: 10.1167/iovs.15-17727] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE We previously showed that Discs large-1 (Dlg-1) regulates lens fiber cell structure and the fibroblast growth factor receptor (Fgfr) signaling pathway, a pathway required for fiber cell differentiation. Herein, we investigated the mechanism through which Dlg-1 regulates Fgfr signaling. METHODS Immunofluorescence was used to measure levels of Fgfr1, Fgfr2, and activated Fgfr signaling intermediates, pErk and pAkt, in control and Dlg-1-deficient lenses that were haplodeficient for Fgfr1 or Fgfr2. Immunoblotting was used to measure levels of N-cadherin, EphA2, β-catenin, and tyrosine-phosphorylated EphA2, Fgfr1, Fgfr2, and Fgfr3 in cytoskeletal-associated and cytosolic fractions of control and Dlg-1-deficient lenses. Complex formation between Dlg-1, N-cadherin, β-catenin, Fgfr1, Fgfr2, Fgfr3, and EphA2 was assessed by coimmunoprecipitation. RESULTS Lenses deficient for Dlg-1 and haplodeficient for Fgfr1 or Fgfr2 showed increased levels of Fgfr2 or Fgfr1, respectively. Levels of pErk and pAkt correlated with the level of Fgfr2. N-cadherin was reduced in the cytoskeletal-associated fraction and increased in the cytosolic fraction of Dlg-1-deficient lenses. Dlg-1 complexed with β-catenin, EphA2, Fgfr1, Fgfr2, and Fgfr3. EphA2 complexed with N-cadherin, β-catenin, Fgfr1, Fgfr2, and Fgfr3. Levels of these interactions were altered in Dlg-1-deficient lenses. Loss of Dlg-1 led to changes in Fgfr1, Fgfr2, Fgfr3, and EphA2 levels and to greater changes in the levels of their activation. CONCLUSIONS Dlg-1 complexes with and regulates the activities of EphA2, Fgfr1, Fgfr2, and Fgfr3. As EphA2 contains a Psd95/Dlg/ZO-1 (PDZ) binding motif, whereas Fgfrs do not, we propose that the PDZ protein, Dlg-1, modulates Fgfr signaling through regulation of EphA2.
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33
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Hamada N, Fujimichi Y. Role of carcinogenesis related mechanisms in cataractogenesis and its implications for ionizing radiation cataractogenesis. Cancer Lett 2015; 368:262-74. [DOI: 10.1016/j.canlet.2015.02.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/09/2015] [Accepted: 02/10/2015] [Indexed: 12/20/2022]
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Lin Q, Zhou N, Zhang N, Qi Y. Mutational screening of EFNA5 in Chinese age-related cataract patients. Ophthalmic Res 2014; 52:124-9. [PMID: 25300504 DOI: 10.1159/000363139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 04/18/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIM In the past few years, Ephrin-A5 (EFNA5) had been identified to be associated with lens development, but so far no sequence variation in EFNA5 has been reported in humans. Therefore, we conduct this study to investigate the EFNA5 genetic variations in Chinese age-related cataract (ARC) patients. METHODS Sequencing of EFNA5 was performed in 140 sporadic ARC patients and 142 random unrelated healthy subjects. Genomic DNA was extracted from peripheral blood leukocytes. All exons of EFNA5 were sequenced after being amplified by polymerase chain reaction. The functional consequences of the variations were analyzed using PolyPhen2. RESULTS Three single nucleotide polymorphisms in EFNA5, c.668C>T (rs201008479), c.102C>T (rs199980747) and c.-27C>G (rs200187971), were found in the patients, and none of them presented in the normal controls. Using PolyPhen2, c.668C>T in EFNA5 is predicted to be possibly damaging. CONCLUSIONS The genetic variations c.668C>T (rs201008479), c.102C>T (rs199980747) and c.-27C>G (rs200187971) may present an additional genetic risk factor for ARC in the Chinese population. This study shows the first cases of these genetic variations in EFNA5 in human beings.
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Affiliation(s)
- Qinghong Lin
- Department of Ophthalmology, The Second Affiliated Hospital of Harbin Medical University, Harbin, PR China
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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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Son AI, Sheleg M, Cooper MA, Sun Y, Kleiman NJ, Zhou R. Formation of persistent hyperplastic primary vitreous in ephrin-A5-/- mice. Invest Ophthalmol Vis Sci 2014; 55:1594-606. [PMID: 24550361 DOI: 10.1167/iovs.13-12706] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Primary vitreous regression is a critical event in mammalian eye development required for proper ocular maturity and unhindered vision. Failure of this event results in the eye disease persistent hyperplastic primary vitreous (PHPV), also identified as persistent fetal vasculature (PFV), a condition characterized by the presence of a fibrovascular mass adjacent to the lens and retina, and associated with visual disability and blindness. Here, we identify ephrin-A5 to be a critical regulator for primary vitreous regression. METHODS Wild-type and ephrin-A5(-/-) eyes were examined at various developmental stages to determine the progression of PHPV. Eye tissue was sectioned and examined by H&E staining. Protein expression and localization was determined through immunohistochemistry. Relative levels of Eph receptors were determined by RT-PCR. RESULTS Ephrin-A5(-/-) animals develop ocular phenotypes representative of PHPV, most notably the presence of a large hyperplastic mass posterior to the lens that remains throughout the lifetime of the animal. The aberrant tissue in these mutant mice consists of residual hyaloid vessels surrounded by pigmented cells of neural crest origin. Labeling with bromodeoxyuridine (BrdU) and detection of proliferating cell nuclear antigen (PCNA) expression shows that the mass in ephrin-A5(-/-) animals is mitotically active in embryonic and postnatal stages. CONCLUSIONS Ephrin-A5 is a critical factor that regulates primary vitreous regression.
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Affiliation(s)
- Alexander I Son
- Department of Chemical Biology, Susan Lehman-Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, New Jersey
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Bone marrow mesenchymal stem cells stimulate proliferation and neuronal differentiation of retinal progenitor cells. PLoS One 2013; 8:e76157. [PMID: 24098776 PMCID: PMC3786983 DOI: 10.1371/journal.pone.0076157] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/20/2013] [Indexed: 11/19/2022] Open
Abstract
During retina development, retinal progenitor cell (RPC) proliferation and differentiation are regulated by complex inter- and intracellular interactions. Bone marrow mesenchymal stem cells (BMSCs) are reported to express a variety of cytokines and neurotrophic factors, which have powerful trophic and protective functions for neural tissue-derived cells. Here, we show that the expanded RPC cultures treated with BMSC-derived conditioned medium (CM) which was substantially enriched for bFGF and CNTF, expressed clearly increased levels of nuclear receptor TLX, an essential regulator of neural stem cell (NSC) self-renewal, as well as betacellulin (BTC), an EGF-like protein described as supporting NSC expansion. The BMSC CM- or bFGF-treated RPCs also displayed an obviously enhanced proliferation capability, while BMSC CM-derived bFGF knocked down by anti-bFGF, the effect of BMSC CM on enhancing RPC proliferation was partly reversed. Under differentiation conditions, treatment with BMSC CM or CNTF markedly favoured RPC differentiation towards retinal neurons, including Brn3a-positive retinal ganglion cells (RGCs) and rhodopsin-positive photoreceptors, and clearly diminished retinal glial cell differentiation. These findings demonstrate that BMSCs supported RPC proliferation and neuronal differentiation which may be partly mediated by BMSC CM-derived bFGF and CNTF, reveal potential limitations of RPC culture systems, and suggest a means for optimizing RPC cell fate determination in vitro.
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Cheng C, Ansari MM, Cooper JA, Gong X. EphA2 and Src regulate equatorial cell morphogenesis during lens development. Development 2013; 140:4237-45. [PMID: 24026120 DOI: 10.1242/dev.100727] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
High refractive index and transparency of the eye lens require uniformly shaped and precisely aligned lens fiber cells. During lens development, equatorial epithelial cells undergo cell-to-cell alignment to form meridional rows of hexagonal cells. The mechanism that controls this morphogenesis from randomly packed cuboidal epithelial cells to highly organized hexagonal fiber cells remains unknown. In Epha2(-/-) mouse lenses, equatorial epithelial cells fail to form precisely aligned meridional rows; moreover, the lens fulcrum, where the apical tips of elongating epithelial cells constrict to form an anchor point before fiber cell differentiation and elongation at the equator, is disrupted. Phosphorylated Src-Y424 and cortactin-Y466, actin and EphA2 cluster at the vertices of wild-type hexagonal epithelial cells in organized meridional rows. However, phosphorylated Src and phosphorylated cortactin are not detected in disorganized Epha2(-/-) cells with altered F-actin distribution. E-cadherin junctions, which are normally located at the basal-lateral ends of equatorial epithelial cells and are diminished in newly differentiating fiber cells, become widely distributed in the apical, lateral and basal sides of epithelial cells and persist in differentiating fiber cells in Epha2(-/-) lenses. Src(-/-) equatorial epithelial cells also fail to form precisely aligned meridional rows and lens fulcrum. These results indicate that EphA2/Src signaling is essential for the formation of the lens fulcrum. EphA2 also regulates Src/cortactin/F-actin complexes at the vertices of hexagonal equatorial cells for cell-to-cell alignment. This mechanistic information explains how EphA2 mutations lead to disorganized lens cells that subsequently contribute to altered refractive index and cataracts in humans and mice.
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Affiliation(s)
- Catherine Cheng
- School of Optometry and Vision Science Program, University of California Berkeley, Berkeley, CA 94720, USA
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Dave A, Laurie K, Staffieri SE, Taranath D, Mackey DA, Mitchell P, Wang JJ, Craig JE, Burdon KP, Sharma S. Mutations in the EPHA2 gene are a major contributor to inherited cataracts in South-Eastern Australia. PLoS One 2013; 8:e72518. [PMID: 24014202 PMCID: PMC3754966 DOI: 10.1371/journal.pone.0072518] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 07/05/2013] [Indexed: 12/21/2022] Open
Abstract
Congenital cataract is the most common cause of treatable visual impairment in children worldwide. Mutations in many different genes lead to congenital cataract. Recently, mutations in the receptor tyrosine kinase gene, EPHA2, have been found to cause congenital cataract in six different families. Although these findings have established EPHA2 as a causative gene, the total contribution of mutations in this gene to congenital cataract is unknown. In this study, for the first time, a population-based approach was used to investigate the frequency of disease causing mutations in the EPHA2 gene in inherited cataract cases in South-Eastern Australia. A cohort of 84 familial congenital or juvenile cataract index cases was screened for mutations in the EPHA2 gene by direct sequencing. Novel changes were assessed for segregation with the disease within the family and in unrelated controls. Microsatellite marker analysis was performed to establish any relationship between families carrying the same mutation. We report a novel congenital cataract causing mutation c.1751C>T in the EPHA2 gene and the previously reported splice mutation c.2826-9G>A in two new families. Additionally, we report a rare variant rs139787163 potentially associated with increased susceptibility to cataract. Thus mutations in EPHA2 account for 4.7% of inherited cataract cases in South-Eastern Australia. Interestingly, the identified rare variant provides a link between congenital and age-related cataract.
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Affiliation(s)
- Alpana Dave
- Department of Ophthalmology, Flinders University, Bedford Park, SA, Australia
| | - Kate Laurie
- Department of Ophthalmology, Flinders University, Bedford Park, SA, Australia
| | - Sandra E. Staffieri
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- Royal Children’s Hospital, Melbourne, Australia
| | - Deepa Taranath
- Department of Ophthalmology, Flinders University, Bedford Park, SA, Australia
| | - David A. Mackey
- Lions Eye Institute, University of Western Australia, Centre for Ophthalmology and Visual Science, Perth, Australia
- Discipline of Medicine, University of Tasmania, Hobart, Australia
| | - Paul Mitchell
- Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, The University of Sydney, Sydney, NSW, Australia
| | - Jie Jin Wang
- Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, The University of Sydney, Sydney, NSW, Australia
| | - Jamie E. Craig
- Department of Ophthalmology, Flinders University, Bedford Park, SA, Australia
| | - Kathryn P. Burdon
- Department of Ophthalmology, Flinders University, Bedford Park, SA, Australia
| | - Shiwani Sharma
- Department of Ophthalmology, Flinders University, Bedford Park, SA, Australia
- * E-mail:
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Park JE, Son AI, Zhou R. Roles of EphA2 in Development and Disease. Genes (Basel) 2013; 4:334-57. [PMID: 24705208 PMCID: PMC3924825 DOI: 10.3390/genes4030334] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/22/2013] [Accepted: 05/23/2013] [Indexed: 01/12/2023] Open
Abstract
The Eph family of receptor tyrosine kinases (RTKs) has been implicated in the regulation of many aspects of mammalian development. Recent analyses have revealed that the EphA2 receptor is a key modulator for a wide variety of cellular functions. This review focuses on the roles of EphA2 in both development and disease.
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Affiliation(s)
- Jeong Eun Park
- Susan Lehman-Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA.
| | - Alexander I Son
- Susan Lehman-Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA.
| | - Renping Zhou
- Susan Lehman-Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA.
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Son AI, Cooper MA, Sheleg M, Sun Y, Kleiman NJ, Zhou R. Further analysis of the lens of ephrin-A5-/- mice: development of postnatal defects. Mol Vis 2013; 19:254-66. [PMID: 23401654 PMCID: PMC3566898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 02/01/2013] [Indexed: 11/06/2022] Open
Abstract
PURPOSE The cells of the mammalian lens must be carefully organized and regulated to maintain clarity. Recent studies have identified the Eph receptor ligand ephrin-A5 as a major contributor to lens development, as mice lacking ephrin-A5 develop abnormal lenses, resulting in cataracts. As a follow-up to our previous study on the cataracts observed in ephrin-A5(-/-) animals, we have further examined the morphological and molecular changes in the ephrin-A5(-/-) lens. METHODS Wild-type and ephrin-A5(-/-) eyes at various ages were fixed, sectioned, and examined using histological techniques. Protein expression and localization were determined using immunohistochemistry and western blot analysis. RESULTS Lens abnormalities in the ephrin-A5(-/-) animals are observed at postnatal stages, with lens opacity occurring by postnatal day 21. Structural defects in the lens are first observed in the outer lens fiber cell region where cells in the ephrin-A5(-/-) lens are severely disorganized. Ephrin-A5 and the Eph receptor EphA2 are expressed during early ocular development and continue to be expressed into postnatal stages. The cataracts in the ephrin-A5(-/-) mutants occur regardless of the presence of the CP49 mutation. CONCLUSIONS In this follow-up study, we have uncovered additional details explicating the mechanisms underlying ephrin-A5 function in the lens. Furthermore, elucidation of the expression of ephrin-A5 and the Eph receptor EphA2 in the lens supports a fundamental role for this receptor-ligand complex in lens development. These observations, in concert with our previous study, strongly suggest that ephrin-A5 has a critical role in postnatal lens fiber organization to maintain lens transparency.
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Affiliation(s)
- Alexander I. Son
- Department of Chemical Biology, Susan Lehman-Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ
| | - Margaret A. Cooper
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Michal Sheleg
- Department of Chemical Biology, Susan Lehman-Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ
| | - Yuhai Sun
- Department of Chemical Biology, Susan Lehman-Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ
| | - Norman J. Kleiman
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY
| | - Renping Zhou
- Department of Chemical Biology, Susan Lehman-Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ
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Pax6 interactions with chromatin and identification of its novel direct target genes in lens and forebrain. PLoS One 2013; 8:e54507. [PMID: 23342162 PMCID: PMC3544819 DOI: 10.1371/journal.pone.0054507] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 12/12/2012] [Indexed: 01/22/2023] Open
Abstract
Pax6 encodes a specific DNA-binding transcription factor that regulates the development of multiple organs, including the eye, brain and pancreas. Previous studies have shown that Pax6 regulates the entire process of ocular lens development. In the developing forebrain, Pax6 is expressed in ventricular zone precursor cells and in specific populations of neurons; absence of Pax6 results in disrupted cell proliferation and cell fate specification in telencephalon. In the pancreas, Pax6 is essential for the differentiation of α-, β- and δ-islet cells. To elucidate molecular roles of Pax6, chromatin immunoprecipitation experiments combined with high-density oligonucleotide array hybridizations (ChIP-chip) were performed using three distinct sources of chromatin (lens, forebrain and β-cells). ChIP-chip studies, performed as biological triplicates, identified a total of 5,260 promoters occupied by Pax6. 1,001 (133) of these promoter regions were shared between at least two (three) distinct chromatin sources, respectively. In lens chromatin, 2,335 promoters were bound by Pax6. RNA expression profiling from Pax6+/− lenses combined with in vivo Pax6-binding data yielded 76 putative Pax6-direct targets, including the Gaa, Isl1, Kif1b, Mtmr2, Pcsk1n, and Snca genes. RNA and ChIP data were validated for all these genes. In lens cells, reporter assays established Kib1b and Snca as Pax6 activated and repressed genes, respectively. In situ hybridization revealed reduced expression of these genes in E14 cerebral cortex. Moreover, we examined differentially expressed transcripts between E9.5 wild type and Pax6−/− lens placodes that suggested Efnb2, Fat4, Has2, Nav1, and Trpm3 as novel Pax6-direct targets. Collectively, the present studies, through the identification of Pax6-direct target genes, provide novel insights into the molecular mechanisms of Pax6 gene control during mouse embryonic development. In addition, the present data demonstrate that Pax6 interacts preferentially with promoter regions in a tissue-specific fashion. Nevertheless, nearly 20% of the regions identified are accessible to Pax6 in multiple tissues.
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Hogerheyde TA, Stephenson SA, Harkin DG, Bray LJ, Madden PW, Woolf MI, Richardson NA. Evaluation of Eph receptor and ephrin expression within the human cornea and limbus. Exp Eye Res 2012; 107:110-20. [PMID: 23247085 DOI: 10.1016/j.exer.2012.11.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 10/18/2012] [Accepted: 11/27/2012] [Indexed: 11/28/2022]
Abstract
Eph receptor tyrosine kinases and their ligands, the ephrins, regulate the development and maintenance of multiple organs but little is known about their potential role within the cornea. The purpose of this study was to perform a thorough investigation of Eph/ephrin expression within the human cornea including the limbal stem cell niche. Initially, immunohistochemistry was performed on human donor eyes to determine the spatial distribution of Eph receptors and ephrins in the cornea and limbus. Patterns of Eph/ephrin gene expression in (1) immortalised human corneal endothelial (B4G12) or corneal epithelial (HCE-T) cell lines, and (2) primary cultures of epithelial or stromal cells established from the corneal limbus of cadaveric eye tissue were then assessed by reverse transcription (RT) PCR. Limbal epithelial or stromal cells from primary cultures were also assessed for evidence of Eph/ephrin-reactivity by immunofluorescence. Immunoreactivity for ephrinA1 and EphB4 was detected in the corneal endothelium of donor eyes. EphB4 was also consistently detected in the limbal and corneal epithelium and in cells located in the stroma of the peripheral cornea. Expression of multiple Eph/ephrin genes was detected in immortalised corneal epithelial and endothelial cell lines. Evidence of Eph/ephrin gene expression was also demonstrated in primary cultures of human limbal stromal (EphB4, B6; ephrinA5) and epithelial cells (EphA1, A2; ephrinA5, B2) using both RT-PCR and immunofluorescence. The expression of Eph receptors and ephrins within the human cornea and limbus is much wider than previously appreciated and suggests multiple potential roles for these molecules in the maintenance of normal corneal architecture.
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Affiliation(s)
- Thomas A Hogerheyde
- School of Biomedical Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, Queensland 4001, Australia.
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Watanabe K, Wada K, Ohashi T, Okubo S, Takekuma K, Hashizume R, Hayashi JI, Serikawa T, Kuramoto T, Kikkawa Y. A 5-bp insertion in Mip causes recessive congenital cataract in KFRS4/Kyo rats. PLoS One 2012; 7:e50737. [PMID: 23226368 PMCID: PMC3511373 DOI: 10.1371/journal.pone.0050737] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 10/24/2012] [Indexed: 11/19/2022] Open
Abstract
We discovered a new cataract mutation, kfrs4, in the Kyoto Fancy Rat Stock (KFRS) background. Within 1 month of birth, all kfrs4/kfrs4 homozygotes developed cataracts, with severe opacity in the nuclei of the lens. In contrast, no opacity was observed in the kfrs4/+ heterozygotes. We continued to observe these rats until they reached 1 year of age and found that cataractogenesis did not occur in kfrs4/+ rats. To define the histological defects in the lenses of kfrs4 rats, sections of the eyes of these rats were prepared. Although the lenses of kfrs4/kfrs4 homozygotes showed severely disorganised fibres and vacuolation, the lenses of kfrs4/+ heterozygotes appeared normal and similar to those of wild-type rats. We used positional cloning to identify the kfrs4 mutation. The mutation was mapped to an approximately 9.7-Mb region on chromosome 7, which contains the Mip gene. This gene is responsible for a dominant form of cataract in humans and mice. Sequence analysis of the mutant-derived Mip gene identified a 5-bp insertion. This insertion is predicted to inactivate the MIP protein, as it produces a frameshift that results in the synthesis of 6 novel amino acid residues and a truncated protein that lacks 136 amino acids in the C-terminal region, and no MIP immunoreactivity was observed in the lens fibre cells of kfrs4/kfrs4 homozygous rats using an antibody that recognises the C- and N-terminus of MIP. In addition, the kfrs4/+ heterozygotes showed reduced expression of Mip mRNA and MIP protein and the kfrs4/kfrs4 homozygotes showed no expression in the lens. These results indicate that the kfrs4 mutation conveys a loss-of-function, which leads to functional inactivation though the degradation of Mip mRNA by an mRNA decay mechanism. Therefore, the kfrs4 rat represents the first characterised rat model with a recessive mutation in the Mip gene.
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Affiliation(s)
- Kei Watanabe
- Mammalian Genetics Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kenta Wada
- Mammalian Genetics Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- Department of Bioproduction, Tokyo University of Agriculture, Abashiri, Japan
| | - Tomoko Ohashi
- Department of Bioproduction, Tokyo University of Agriculture, Abashiri, Japan
| | - Saki Okubo
- Department of Bioproduction, Tokyo University of Agriculture, Abashiri, Japan
| | - Kensuke Takekuma
- Department of Bioproduction, Tokyo University of Agriculture, Abashiri, Japan
| | - Ryoichi Hashizume
- Department of Bioproduction, Tokyo University of Agriculture, Abashiri, Japan
| | - Jun-Ichi Hayashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tadao Serikawa
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takashi Kuramoto
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoshiaki Kikkawa
- Mammalian Genetics Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- * E-mail:
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Son AI, Park JE, Zhou R. The role of Eph receptors in lens function and disease. SCIENCE CHINA-LIFE SCIENCES 2012; 55:434-43. [PMID: 22645087 DOI: 10.1007/s11427-012-4318-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 04/27/2012] [Indexed: 12/27/2022]
Abstract
Cataract is the single largest contributor to blindness in the world, with the disease having a strong genetic component. In recent years the Eph family of receptor tyrosine kinases has been identified as a key regulator in lens clarity. In this review we discuss the roles of the Eph receptors in lens biology and cataract development.
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Affiliation(s)
- Alexander I Son
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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