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Millán Cotto HA, Pathrikar TV, Hakim B, Baby HM, Zhang H, Zhao P, Ansaripour R, Amini R, Carrier RL, Bajpayee AG. Cationic-motif-modified exosomes for mRNA delivery to retinal photoreceptors. J Mater Chem B 2024. [PMID: 38946491 DOI: 10.1039/d4tb00849a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Topical treatment of vitreoretinal diseases remains a challenge due to slow corneal uptake and systemic clearance. Exosomes are emerging nanocarriers for drug delivery due to biocompatibility and cellular targeting properties. To apply them for retinal targeting via the topical route, exosomes must traverse various ocular barriers including the cornea, lens, vitreous humor (VH), and the retina itself. Here we engineered high-purity milk-derived exosomes by anchoring arginine-rich cationic motifs via PEG2000 lipid insertion on their surface. Modification enabled exosomes to use weak-reversible electrostatic interactions with anionic glycosaminoglycan (GAG) and water content of the tissue to enhance their transport rate and retention. Addition of cationic motifs neutralized the anionic surface charge of exosomes (-24 to -2 mV) without impacting size or morphology. Cationic-motif-modified exosomes exhibited two-fold faster steady state diffusivity through bovine corneas compared to unmodified exosomes. Fluorescence recovery after photobleaching confirmed that cationic-motif-modified exosomes can diffuse through VH without steric hindrance. In healthy VH, cationic-motif-modified exosomes demonstrated stronger binding resulting in three-fold lower average diffusivity that enhanced by six-fold in 50% GAG-depleted VH recapitulating advanced liquefaction. Cationic-motif-modified exosomes penetrated through the full-thickness of porcine retinal explants resulting in ten-fold higher uptake in photoreceptors and three-fold greater transfection with encapsulated eGFP mRNA compared to unmodified exosomes. Cationic-motif-modified exosomes are safe to use as they did not adversely affect the mechanical swelling properties of the cornea or lens nor impact retinal cell viability. Cationic-motif-modified exosomes, therefore, offer themselves as a cell-free nanocarrier platform for gene delivery to retinal photoreceptors potentially via the topical route.
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Affiliation(s)
| | | | - Bill Hakim
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
| | - Helna M Baby
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
| | - Hengli Zhang
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
| | - Peng Zhao
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.
| | - Ronak Ansaripour
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
| | - Rouzbeh Amini
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115, USA
| | - Rebecca L Carrier
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.
| | - Ambika G Bajpayee
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115, USA
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2
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Melrose J. Keratan sulfate, an electrosensory neurosentient bioresponsive cell instructive glycosaminoglycan. Glycobiology 2024; 34:cwae014. [PMID: 38376199 PMCID: PMC10987296 DOI: 10.1093/glycob/cwae014] [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: 01/18/2024] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/21/2024] Open
Abstract
The roles of keratan sulfate (KS) as a proton detection glycosaminoglycan in neurosensory processes in the central and peripheral nervous systems is reviewed. The functional properties of the KS-proteoglycans aggrecan, phosphacan, podocalyxcin as components of perineuronal nets in neurosensory processes in neuronal plasticity, cognitive learning and memory are also discussed. KS-glycoconjugate neurosensory gels used in electrolocation in elasmobranch fish species and KS substituted mucin like conjugates in some tissue contexts in mammals need to be considered in sensory signalling. Parallels are drawn between KS's roles in elasmobranch fish neurosensory processes and its roles in mammalian electro mechanical transduction of acoustic liquid displacement signals in the cochlea by the tectorial membrane and stereocilia of sensory inner and outer hair cells into neural signals for sound interpretation. The sophisticated structural and functional proteins which maintain the unique high precision physical properties of stereocilia in the detection, transmittance and interpretation of acoustic signals in the hearing process are important. The maintenance of the material properties of stereocilia are essential in sound transmission processes. Specific, emerging roles for low sulfation KS in sensory bioregulation are contrasted with the properties of high charge density KS isoforms. Some speculations are made on how the molecular and electrical properties of KS may be of potential application in futuristic nanoelectronic, memristor technology in advanced ultrafast computing devices with low energy requirements in nanomachines, nanobots or molecular switches which could be potentially useful in artificial synapse development. Application of KS in such innovative areas in bioregulation are eagerly awaited.
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Affiliation(s)
- James Melrose
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
- Raymond Purves Laboratory, Institute of Bone and Joint Research, Kolling Institute of Medical Research, Northern Sydney Local Health District, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
- Sydney Medical School, Northern, University of Sydney at Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
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3
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Williams BN, Draper A, Lang PF, Lewis TR, Smith AL, Mayerl SJ, Rougié M, Simon JM, Arshavsky VY, Greenwald SH, Gamm DM, Pinilla I, Philpot BD. Heterogeneity in the progression of retinal pathologies in mice harboring patient mimicking Impg2 mutations. Hum Mol Genet 2024; 33:448-464. [PMID: 37975905 PMCID: PMC10877459 DOI: 10.1093/hmg/ddad199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023] Open
Abstract
Biallelic mutations in interphotoreceptor matrix proteoglycan 2 (IMPG2) in humans cause retinitis pigmentosa (RP) with early macular involvement, albeit the disease progression varies widely due to genetic heterogeneity and IMPG2 mutation type. There are currently no treatments for IMPG2-RP. To aid preclinical studies toward eventual treatments, there is a need to better understand the progression of disease pathology in appropriate animal models. Toward this goal, we developed mouse models with patient mimicking homozygous frameshift (T807Ter) or missense (Y250C) Impg2 mutations, as well as mice with a homozygous frameshift mutation (Q244Ter) designed to completely prevent IMPG2 protein expression, and characterized the trajectory of their retinal pathologies across postnatal development until late adulthood. We found that the Impg2T807Ter/T807Ter and Impg2Q244Ter/Q244Ter mice exhibited early onset gliosis, impaired photoreceptor outer segment maintenance, appearance of subretinal deposits near the optic disc, disruption of the outer retina, and neurosensorial detachment, whereas the Impg2Y250C/Y250C mice exhibited minimal retinal pathology. These results demonstrate the importance of mutation type in disease progression in IMPG2-RP and provide a toolkit and preclinical data for advancing therapeutic approaches.
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Affiliation(s)
- Brittany N Williams
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Adam Draper
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Patrick F Lang
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Tylor R Lewis
- Department of Ophthalmology, Duke University, Durham, NC 27705, United States
| | - Audrey L Smith
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Steven J Mayerl
- Department of Ophthalmology and Visual Sciences, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, United States
| | - Marie Rougié
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Jeremy M Simon
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University, Durham, NC 27705, United States
| | | | - David M Gamm
- Department of Ophthalmology and Visual Sciences, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, United States
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza 50009, Spain
- Aragón Health Research Institute (IIS Aragón), Zaragoza 50009, Spain
- Department of Surgery, University of Zaragoza, Zaragoza 50009, Spain
| | - Benjamin D Philpot
- Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, United States
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, United States
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4
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Castellini ME, Spagnolli G, Poggi L, Biasini E, Casarosa S, Messina A. Identification of the zebrafish homologues of IMPG2, a retinal proteoglycan. Cell Tissue Res 2023; 394:93-105. [PMID: 37470839 PMCID: PMC10558372 DOI: 10.1007/s00441-023-03808-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023]
Abstract
Photoreceptor outer segments are surrounded by a carbohydrate-rich matrix, the interphotoreceptor matrix, necessary for physiological retinal function. Few roles for molecules characterizing the interphotoreceptor matrix have been clearly defined. Recent studies have found the presence of nonsense mutations in the interphotoreceptor matrix proteoglycan 2 (IMPG2) gene in patients affected by retinal dystrophies. IMPG2 encodes for a proteoglycan synthesized by photoreceptors and secreted in the interphotoreceptor matrix. Little is known about the structure and function of this protein, we thus decided to characterize zebrafish impg2. In zebrafish there are two Impg2 proteins, Impg2a and Impg2b. We generated a phylogenetic tree based on IMPG2 protein sequence similarity among vertebrates, showing a significant similarity between humans and teleosts. The human and zebrafish proteins share conserved domains, as also shown by homology models. Expression analyses of impg2a and impg2b show a continued expression in the photoreceptor layer starting from developmental stages and continuing through adulthood. Between 1 and 6 months post-fertilization, there is a significant shift of Impg2 expression toward the outer segment region, suggesting an increase in secretion. This raises intriguing hypotheses about its possible role(s) during retinal maturation, laying the groundwork for the generation of most needed models for the study of IMPG2-related inherited retinal dystrophies.
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Affiliation(s)
- M E Castellini
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive, 9, 38123, Povo, TN, Italy
| | - G Spagnolli
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive, 9, 38123, Povo, TN, Italy
- Sibylla Biotech S.R.L, Piazzetta Chiavica 2 - 37121, Verona, VR, Italy
| | - L Poggi
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive, 9, 38123, Povo, TN, Italy
- Centre for Medical Sciences (CISMed), University of Trento, Via S. Maria Maddalena, 1, 38122, Trento, TN, Italy
| | - E Biasini
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive, 9, 38123, Povo, TN, Italy
- Centre for Medical Sciences (CISMed), University of Trento, Via S. Maria Maddalena, 1, 38122, Trento, TN, Italy
| | - S Casarosa
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive, 9, 38123, Povo, TN, Italy.
- Centre for Medical Sciences (CISMed), University of Trento, Via S. Maria Maddalena, 1, 38122, Trento, TN, Italy.
| | - A Messina
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive, 9, 38123, Povo, TN, Italy
- Centre for Mind/Brain Sciences (CIMeC), University of Trento, Piazza Manifattura 1, 38068, Rovereto, TN, Italy
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5
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Zhang R, Li B, Li H. Extracellular-Matrix Mechanics Regulate the Ocular Physiological and Pathological Activities. J Ophthalmol 2023; 2023:7626920. [PMID: 37521908 PMCID: PMC10386902 DOI: 10.1155/2023/7626920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 07/06/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023] Open
Abstract
The extracellular matrix (ECM) is a noncellular structure that plays an indispensable role in a series of cell life activities. Accumulating studies have demonstrated that ECM stiffness, a type of mechanical forces, exerts a pivotal influence on regulating organogenesis, tissue homeostasis, and the occurrence and development of miscellaneous diseases. Nevertheless, the role of ECM stiffness in ophthalmology is rarely discussed. In this review, we focus on describing the important role of ECM stiffness and its composition in multiple ocular structures (including cornea, retina, optic nerve, trabecular reticulum, and vitreous) from a new perspective. The abnormal changes in ECM can trigger physiological and pathological activities of the eye, suggesting that compared with different biochemical factors, the transmission and transduction of force signals triggered by mechanical cues such as ECM stiffness are also universal in different ocular cells. We expect that targeting ECM as a therapeutic approach or designing advanced ECM-based technologies will have a broader application prospect in ophthalmology.
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Affiliation(s)
- Ran Zhang
- Department of Ophthalmology & Optometry, North Sichuan Medical College, Nanchong 637000, Sichuan, China
- Department of Ophthalmology, Central Hospital of Suining City, Suining 629000, Sichuan, China
| | - Bo Li
- Department of Ophthalmology, Central Hospital of Suining City, Suining 629000, Sichuan, China
| | - Heng Li
- Department of Ophthalmology & Optometry, North Sichuan Medical College, Nanchong 637000, Sichuan, China
- Department of Ophthalmology, Central Hospital of Suining City, Suining 629000, Sichuan, China
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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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Parra MM, Spoth E, Ronquillo CC, Henderson R, Hartnett ME. Multimodal Retinal Imaging Findings in Two Cousins With VCAN-Related Vitreoretinopathy or Wagner Disease. Ophthalmic Surg Lasers Imaging Retina 2022; 53:639-643. [PMID: 36378611 DOI: 10.3928/23258160-20221026-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Wagner disease is a rare, nonsyndromic vitreoretinopathy caused by autosomal dominant variants in the versican (VCAN) gene. It is associated with abnormalities of the vitreoretinal interface that can lead to peripheral traction and retinal detachments, which also occur in other vitreoretinopathies such as X-linked retinoschisis (XLRS), familial exudative vitreoretinopathy (FEVR) and Stickler syndrome. There is variability in the clinical phenotype in Wagner disease potentially due to variants in VCAN gene variants. In this article, we report a family harboring the VCAN c.9265+1G>C variant and describe the clinical and retinal findings in two members. [Ophthalmic Surg Lasers Imaging Retina 2022;53:639-643.].
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8
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Menko AS, Romisher A, Walker JL. The Pro-fibrotic Response of Mesenchymal Leader Cells to Lens Wounding Involves Hyaluronic Acid, Its Receptor RHAMM, and Vimentin. Front Cell Dev Biol 2022; 10:862423. [PMID: 35386200 PMCID: PMC8977891 DOI: 10.3389/fcell.2022.862423] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/08/2022] [Indexed: 12/31/2022] Open
Abstract
Hyaluronic Acid/Hyaluronan (HA) is a major component of the provisional matrix deposited by cells post-wounding with roles both in regulating cell migration to repair a wound and in promoting a fibrotic outcome to wounding. Both are mediated through its receptors CD44 and RHAMM. We now showed that HA is present in the provisional matrix assembled on the substrate surface in a lens post-cataract surgery explant wound model in which mesenchymal leader cells populate the wound edges to direct migration of the lens epithelium across the adjacent culture substrate onto which this matrix is assembled. Inhibiting HA expression with 4-MU blocked assembly of FN-EDA and collagen I by the wound-responsive mesenchymal leader cells and their migration. These cells express both the HA receptors CD44 and RHAMM. CD44 co-localized with HA at their cell-cell interfaces. RHAMM was predominant in the lamellipodial protrusions extended by the mesenchymal cells at the leading edge, and along HA fibrils organized on the substrate surface. Within a few days post-lens wounding the leader cells are induced to transition to αSMA+ myofibroblasts. Since HA/RHAMM is implicated in both cell migration and inducing fibrosis we examined the impact of blocking HA synthesis on myofibroblast emergence and discovered that it was dependent on HA. While RHAMM has not been previously linked to the intermediate filament protein vimentin, our studies with these explant cultures have shown that vimentin in the cells’ lamellipodial protrusions regulate their transition to myofibroblast. PLA studies now revealed that RHAMM was complexed with both HA and vimentin in the lamellipodial protrusions of leader cells, implicating this HA/RHAMM/vimentin complex in the regulation of leader cell function post-wounding, both in promoting cell migration and in the transition of these cells to myofibroblasts. These results increase our understanding of how the post-wounding matrix environment interacts with receptor/cytoskeletal complexes to determine whether injury outcomes are regenerative or fibrotic.
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Affiliation(s)
- A Sue Menko
- Department of Pathology, Anatomy and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States.,Department of Ophthalmology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
| | - Alison Romisher
- Department of Pathology, Anatomy and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
| | - Janice L Walker
- Department of Pathology, Anatomy and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States.,Department of Ophthalmology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
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9
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Chatterjee S, Gupta S, Chaudhry VN, Chaudhry P, Mukherjee A, Mutsuddi M. Whole exome sequencing identifies a novel splice-site mutation in IMPG2 gene causing Stargardt-like juvenile macular dystrophy in a north Indian family. Gene 2022; 816:146158. [PMID: 34990796 DOI: 10.1016/j.gene.2021.146158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/10/2021] [Indexed: 12/01/2022]
Abstract
We report on the genetic analysis of a north Indian family affected with Stargardt-like juvenile macular dystrophy. Considering an autosomal recessive inheritance of macular dystrophy in the recruited family, whole exome sequencing was employed in two affected siblings and their mother. We have identified a novel splice-site variant NC_000003.11(NM_016247.3):c.1239 + 1G > T, co-segregating in the affected siblings, in the Interphotoreceptor Matrix Proteoglycan 2 (IMPG2) gene. The identified variant is present immediately after exon 11, and is predicted to disrupt the wild-type donor splice-site of IMPG2 transcripts. We confirmed the splice-site changes in the IMPG2 transcripts using minigene functional assay. Although a number of studies on IMPG2 have demonstrated its involvement in retinitis pigmentosa and vitelliform macular dystrophy, this is the first report of a splice-site variant in IMPG2 that is responsible for Stargardt-like juvenile macular dystrophy.
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Affiliation(s)
- Souradip Chatterjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Shashank Gupta
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | | | | | - Ashim Mukherjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Mousumi Mutsuddi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
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10
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Xu H, Qu C, Gan L, Sun K, Tan J, Liu X, Jiang Z, Tian W, Liu W, Zhang S, Yang Y, Jiang L, Zhu X, Zhang L. Deletion of the Impg2 gene causes the degeneration of rod and cone cells in mice. Hum Mol Genet 2021; 29:1624-1634. [PMID: 32242237 DOI: 10.1093/hmg/ddaa062] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/18/2020] [Accepted: 03/30/2020] [Indexed: 11/14/2022] Open
Abstract
Variants in interphotoreceptor matrix proteoglycans (IMPG2) have been reported in retinitis pigmentosa (RP) and vitelliform macular dystrophy (VMD) patients. However, the underlying molecular mechanisms remain elusive due to a lack of suitable disease models. We developed two independent Impg2 knockout (KO) mouse models using the CRISPR/Cas9 technique to assess the in vivo functions of Impg2 in the retina. Impg2 ablation in mice recapitulated the RP phenotypes of patients, including an attenuated electroretinogram (ERG) response and the progressive degeneration of photoreceptors. The histopathological examination of Impg2-KO mice revealed irregularly arranged rod cells and mislocalized rhodopsin protein in the inner segment at 6 months of age. In addition to the pathological changes in rod cells, cone cells were also affected in KO retinas. KO retinas exhibited progressive cone cell death and impaired cone cell elongation. Further immunoblotting analysis revealed increased levels of endoplasmic reticulum (ER) stress-related proteins, including C/EBP homologous protein (CHOP), immunoglobulin heavy-chain-binding protein (BIP) and protein disulfide isomerase (PDI), in Impg2-KO mouse retinas. Increased gliosis and apoptotic cell death were also observed in the KO retinas. As autophagy is closely associated with ER stress, we then checked whether autophagy was disturbed in Impg2-KO mouse retinas. The results showed that autophagy was impaired in KO retinas, as revealed by the increased accumulation of SQSTM1 and other proteins involved in autophagy. Our results demonstrate the essential roles of Impg2 in the retina, and this study provides novel models for mechanistic investigations and development of therapies for RP caused by IMPG2 mutations.
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Affiliation(s)
- Huijuan Xu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Chengdu Institute of Biology, Sichuan Translational Medicine Research Hospital, Chinese Academy of Sciences, Chengdu 610072, Sichuan, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Chao Qu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Li Gan
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Kuanxiang Sun
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Junkai Tan
- Xiamen Eye Center, Xiamen University, Xiamen 361005, China
| | - Xuyang Liu
- Xiamen Eye Center, Xiamen University, Xiamen 361005, China
| | - Zhilin Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Wanli Tian
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Wenjing Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Shanshan Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Yeming Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Li Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China
| | - Xianjun Zhu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Chengdu Institute of Biology, Sichuan Translational Medicine Research Hospital, Chinese Academy of Sciences, Chengdu 610072, Sichuan, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan China.,Research Unit for Blindness Prevention of Chinese Academy of medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan, China.,Department of Ophthalmology, First People's Hospital of Shangqiu, Shangqiu 476000, Henan, China
| | - Lin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.,Research Unit for Blindness Prevention of Chinese Academy of medical Sciences (2019RU026), Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan, China
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11
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Hitti-Malin RJ, Burmeister LM, Ricketts SL, Lewis TW, Pettitt L, Boursnell M, Schofield EC, Sargan D, Mellersh CS. A LINE-1 insertion situated in the promoter of IMPG2 is associated with autosomal recessive progressive retinal atrophy in Lhasa Apso dogs. BMC Genet 2020; 21:100. [PMID: 32894063 PMCID: PMC7487703 DOI: 10.1186/s12863-020-00911-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 08/30/2020] [Indexed: 12/30/2022] Open
Abstract
Background Canine progressive retinal atrophies are a group of hereditary retinal degenerations in dogs characterised by depletion of photoreceptor cells in the retina, which ultimately leads to blindness. PRA in the Lhasa Apso (LA) dog has not previously been clinically characterised or described in the literature, but owners in the UK are advised to have their dog examined through the British Veterinary Association/ Kennel Club/ International Sheep Dog Society (BVA/KC/ISDS) eye scheme annually, and similar schemes that are in operation in other countries. After the exclusion of 25 previously reported canine retinal mutations in LA PRA-affected dogs, we sought to identify the genetic cause of PRA in this breed. Results Analysis of whole-exome sequencing data of three PRA-affected LA and three LA without signs of PRA did not identify any exonic or splice site variants, suggesting the causal variant was non-exonic. We subsequently undertook a genome-wide association study (GWAS), which identified a 1.3 Mb disease-associated region on canine chromosome 33, followed by whole-genome sequencing analysis that revealed a long interspersed element-1 (LINE-1) insertion upstream of the IMPG2 gene. IMPG2 has previously been implicated in human retinal disease; however, until now no canine PRAs have been associated with this gene. The identification of this PRA-associated variant has enabled the development of a DNA test for this form of PRA in the breed, here termed PRA4 to distinguish it from other forms of PRA described in other breeds. This test has been used to determine the genotypes of over 900 LA dogs. A large cohort of genotyped dogs was used to estimate the allele frequency as between 0.07–0.1 in the UK LA population. Conclusions Through the use of GWAS and subsequent sequencing of a PRA case, we have identified a LINE-1 insertion in the retinal candidate gene IMPG2 that is associated with a form of PRA in the LA dog. Validation of this variant in 447 dogs of 123 breeds determined it was private to LA dogs. We envisage that, over time, the developed DNA test will offer breeders the opportunity to avoid producing dogs affected with this form of PRA.
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Affiliation(s)
- Rebekkah J Hitti-Malin
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK. .,Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK.
| | - Louise M Burmeister
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Sally L Ricketts
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Thomas W Lewis
- The Kennel Club, London, W1J 8AB, UK.,School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Louise Pettitt
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Mike Boursnell
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - Ellen C Schofield
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
| | - David Sargan
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK
| | - Cathryn S Mellersh
- Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, CB8 7UU, UK
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12
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Preclinical challenges for developing long acting intravitreal medicines. Eur J Pharm Biopharm 2020; 153:130-149. [DOI: 10.1016/j.ejpb.2020.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/01/2020] [Accepted: 05/08/2020] [Indexed: 02/07/2023]
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13
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Glycosaminoglycans compositional analysis of Urodele axolotl (Ambystoma mexicanum) and Porcine Retina. Glycoconj J 2019; 36:165-174. [PMID: 30963354 DOI: 10.1007/s10719-019-09863-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/27/2019] [Accepted: 03/05/2019] [Indexed: 12/26/2022]
Abstract
Retinal degenerative diseases, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), are major causes of blindness worldwide. Humans cannot regenerate retina, however, axolotl (Ambystoma mexicanum), a laboratory-bred salamander, can regenerate retinal tissue throughout adulthood. Classic signaling pathways, including fibroblast growth factor (FGF), are involved in axolotl regeneration. Glycosaminoglycan (GAG) interaction with FGF is required for signal transduction in this pathway. GAGs are anionic polysaccharides in extracellular matrix (ECM) that have been implicated in limb and lens regeneration of amphibians, however, GAGs have not been investigated in the context of retinal regeneration. GAG composition is characterized native and decellularized axolotl and porcine retina using liquid chromatography mass spectrometry. Pig was used as a mammalian vertebrate model without the ability to regenerate retina. Chondroitin sulfate (CS) was the main retinal GAG, followed by heparan sulfate (HS), hyaluronic acid, and keratan sulfate in both native and decellularized axolotl and porcine retina. Axolotl retina exhibited a distinctive GAG composition pattern in comparison with porcine retina, including a higher content of hyaluronic acid. In CS, higher levels of 4- and 6- O-sulfation were observed in axolotl retina. The HS composition was greater in decellularized tissues in both axolotl and porcine retina by 7.1% and 15.4%, respectively, and different sulfation patterns were detected in axolotl. Our findings suggest a distinctive GAG composition profile of the axolotl retina set foundation for role of GAGs in homeostatic and regenerative conditions of the axolotl retina and may further our understanding of retinal regenerative models.
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14
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Melrose J. Functional Consequences of Keratan Sulfate Sulfation in Electrosensory Tissues and in Neuronal Regulation. ACTA ACUST UNITED AC 2019; 3:e1800327. [PMID: 32627425 DOI: 10.1002/adbi.201800327] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/16/2019] [Indexed: 12/20/2022]
Abstract
Keratan sulfate (KS) is a functional electrosensory and neuro-instructive molecule. Recent studies have identified novel low sulfation KS in auditory and sensory tissues such as the tectorial membrane of the organ of Corti and the Ampullae of Lorenzini in elasmobranch fish. These are extremely sensitive proton gradient detection systems that send signals to neural interfaces to facilitate audition and electrolocation. High and low sulfation KS have differential functional roles in song learning in the immature male zebra song-finch with high charge density KS in song nuclei promoting brain development and cognitive learning. The conductive properties of KS are relevant to the excitable neural phenotype. High sulfation KS interacts with a large number of guidance and neuroregulatory proteins. The KS proteoglycan microtubule associated protein-1B (MAP1B) stabilizes actin and tubulin cytoskeletal development during neuritogenesis. A second 12 span transmembrane synaptic vesicle associated KS proteoglycan (SV2) provides a smart gel storage matrix for the storage of neurotransmitters. MAP1B and SV2 have prominent roles to play in neuroregulation. Aggrecan and phosphacan have roles in perineuronal net formation and in neuroregulation. A greater understanding of the biology of KS may be insightful as to how neural repair might be improved.
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Affiliation(s)
- James Melrose
- Raymond Purves Bone and Joint Research Laboratories, Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St. Leonards, NSW, 2065, Australia.,Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.,Sydney Medical School, Northern, Sydney University, Royal North Shore Hospital, St. Leonards, NSW, 2065, Australia.,Faculty of Medicine and Health, University of Sydney, Royal North Shore Hospital, St. Leonards, NSW, 2065, Australia
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15
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Cui R, Lwigale P. Expression of the heparin-binding growth factors Midkine and pleiotrophin during ocular development. Gene Expr Patterns 2019; 32:28-37. [PMID: 30825522 DOI: 10.1016/j.gep.2019.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/18/2019] [Accepted: 02/21/2019] [Indexed: 12/17/2022]
Abstract
Midkine (MDK) and Pleiotrophin (PTN) belong to a group of heparin-binding growth factors that has been shown to have pleiotropic functions in various biological processes during development and disease. Development of the vertebrate eye is a multistep process that involves coordinated interactions between neuronal and non-neuronal cells, but very little is known about the potential function of MDK and PTN in these processes. In this study, we demonstrate by section in situ hybridization, the spatiotemporal expression of MDK and PTN during ocular development in chick and mouse. We show that MDK and PTN are expressed in dynamic patterns that overlap in a few non-neuronal tissues in the anterior eye and in neuronal cell layers of the posterior eye. We show that the expression patterns of MDK and PTN are only conserved in a few tissues in chick and mouse but they overlap with the expression of some of their receptors LRP1, RPTPZ, ALK, NOTCH2, ITGβ1, SDC1, and SDC3. The dynamic expression patterns of MDK, PTN and their receptors suggest that they function together during the multistep process of ocular development and they may play important roles in cell proliferation, adhesion, and migration of neuronal and non-neuronal cells.
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Affiliation(s)
- Ruda Cui
- Department of BioSciences, Rice University, Houston, TX, USA
| | - Peter Lwigale
- Department of BioSciences, Rice University, Houston, TX, USA.
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16
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Kim SY, Koetzner CA, Payne AF, Nierode GJ, Yu Y, Wang R, Barr E, Dordick JS, Kramer LD, Zhang F, Linhardt RJ. Glycosaminoglycan Compositional Analysis of Relevant Tissues in Zika Virus Pathogenesis and in Vitro Evaluation of Heparin as an Antiviral against Zika Virus Infection. Biochemistry 2019; 58:1155-1166. [PMID: 30698412 DOI: 10.1021/acs.biochem.8b01267] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Zika virus (ZIKV) is an enveloped RNA virus from the flavivirus family that can cause fetal neural abnormalities in pregnant women. Previously, we established that ZIKV-EP (envelope protein) binds to human placental chondroitin sulfate (CS), suggesting that CS may be a potential host cell surface receptor in ZIKV pathogenesis. In this study, we further characterized the GAG disaccharide composition of other biological tissues (i.e., mosquitoes, fetal brain cells, and eye tissues) in ZIKV pathogenesis to investigate the role of tissue specific GAGs. Heparan sulfate (HS) was the major GAG, and levels of HS-6-sulfo, HS 0S (unsulfated HS), and CS 4S disaccharides were the main differences in the GAG composition of Aedes aegypti and Aedes albopictus mosquitoes. In human fetal neural progenitor and differentiated cells, HS 0S and CS 4S were the main disaccharides. A change in disaccharide composition levels was observed between undifferentiated and differentiated cells. In different regions of the bovine eyes, CS was the major GAG, and the amounts of hyaluronic acid or keratan sulfate varied depending on the region of the eye. Next, we examined heparin (HP) of various structures to investigate their potential in vitro antiviral activity against ZIKV and Dengue virus (DENV) infection in Vero cells. All compounds effectively inhibited DENV replication; however, they surprisingly promoted ZIKV replication. HP of longer chain lengths more strongly promoted activity in ZIKV replication. This study further expands our understanding of role of GAGs in ZIKV pathogenesis and carbohydrate-based antivirals against flaviviral infection.
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Affiliation(s)
- So Young Kim
- Biochemistry and Biophysics Graduate Program, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Cheri A Koetzner
- Wadsworth Center , New York State Department of Health , Slingerlands , New York 12159 , United States
| | - Anne F Payne
- Wadsworth Center , New York State Department of Health , Slingerlands , New York 12159 , United States
| | - Gregory J Nierode
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Yanlei Yu
- Biochemistry and Biophysics Graduate Program, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Rufeng Wang
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Evan Barr
- Department of Biological Science, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Jonathan S Dordick
- Biochemistry and Biophysics Graduate Program, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Department of Biological Science, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Laura D Kramer
- Wadsworth Center , New York State Department of Health , Slingerlands , New York 12159 , United States.,State University of New York at Albany School of Public Health , Albany , New York 12222 , United States
| | - Fuming Zhang
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Robert J Linhardt
- Biochemistry and Biophysics Graduate Program, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Department of Biological Science, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
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17
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Melrose J. Keratan sulfate (KS)-proteoglycans and neuronal regulation in health and disease: the importance of KS-glycodynamics and interactive capability with neuroregulatory ligands. J Neurochem 2019; 149:170-194. [PMID: 30578672 DOI: 10.1111/jnc.14652] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 11/26/2018] [Accepted: 12/13/2018] [Indexed: 12/18/2022]
Abstract
Compared to the other classes of glycosaminoglycans (GAGs), that is, chondroitin/dermatan sulfate, heparin/heparan sulfate and hyaluronan, keratan sulfate (KS), have the least known of its interactive properties. In the human body, the cornea and the brain are the two most abundant tissue sources of KS. Embryonic KS is synthesized as a linear poly-N-acetyllactosamine chain of d-galactose-GlcNAc repeat disaccharides which become progressively sulfated with development, sulfation of GlcNAc is more predominant than galactose. KS contains multi-sulfated high-charge density, monosulfated and non-sulfated poly-N-acetyllactosamine regions and thus is a heterogeneous molecule in terms of chain length and charge distribution. A recent proteomics study on corneal KS demonstrated its interactivity with members of the Slit-Robbo and Ephrin-Ephrin receptor families and proteins which regulate Rho GTPase signaling and actin polymerization/depolymerization in neural development and differentiation. KS decorates a number of peripheral nervous system/CNS proteoglycan (PG) core proteins. The astrocyte KS-PG abakan defines functional margins of the brain and is up-regulated following trauma. The chondroitin sulfate/KS PG aggrecan forms perineuronal nets which are dynamic neuroprotective structures with anti-oxidant properties and roles in neural differentiation, development and synaptic plasticity. Brain phosphacan a chondroitin sulfate, KS, HNK-1 PG have roles in neural development and repair. The intracellular microtubule and synaptic vesicle KS-PGs MAP1B and SV2 have roles in metabolite transport, storage, and export of neurotransmitters and cytoskeletal assembly. MAP1B has binding sites for tubulin and actin through which it promotes cytoskeletal development in growth cones and is highly expressed during neurite extension. The interactive capability of KS with neuroregulatory ligands indicate varied roles for KS-PGs in development and regenerative neural processes.
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Affiliation(s)
- James Melrose
- Raymond Purves Bone and Joint Research Laboratory, Kolling Institute, St. Leonards, New South Wales, Australia.,Graduate School of Biomedical Engineering, University of New South Wales, Sydney, New South Wales, Australia.,Sydney Medical School, Northern Campus, Royal North Shore Hospital, The University of Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Royal North Shore Hospital, The University of Sydney, St. Leonards, New South Wales, Australia
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18
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Verbakel SK, van Huet RAC, Boon CJF, den Hollander AI, Collin RWJ, Klaver CCW, Hoyng CB, Roepman R, Klevering BJ. Non-syndromic retinitis pigmentosa. Prog Retin Eye Res 2018; 66:157-186. [PMID: 29597005 DOI: 10.1016/j.preteyeres.2018.03.005] [Citation(s) in RCA: 492] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/20/2018] [Accepted: 03/22/2018] [Indexed: 12/23/2022]
Abstract
Retinitis pigmentosa (RP) encompasses a group of inherited retinal dystrophies characterized by the primary degeneration of rod and cone photoreceptors. RP is a leading cause of visual disability, with a worldwide prevalence of 1:4000. Although the majority of RP cases are non-syndromic, 20-30% of patients with RP also have an associated non-ocular condition. RP typically manifests with night blindness in adolescence, followed by concentric visual field loss, reflecting the principal dysfunction of rod photoreceptors; central vision loss occurs later in life due to cone dysfunction. Photoreceptor function measured with an electroretinogram is markedly reduced or even absent. Optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging show a progressive loss of outer retinal layers and altered lipofuscin distribution in a characteristic pattern. Over the past three decades, a vast number of disease-causing variants in more than 80 genes have been associated with non-syndromic RP. The wide heterogeneity of RP makes it challenging to describe the clinical findings and pathogenesis. In this review, we provide a comprehensive overview of the clinical characteristics of RP specific to genetically defined patient subsets. We supply a unique atlas with color fundus photographs of most RP subtypes, and we discuss the relevant considerations with respect to differential diagnoses. In addition, we discuss the genes involved in the pathogenesis of RP, as well as the retinal processes that are affected by pathogenic mutations in these genes. Finally, we review management strategies for patients with RP, including counseling, visual rehabilitation, and current and emerging therapeutic options.
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Affiliation(s)
- Sanne K Verbakel
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ramon A C van Huet
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands; Department of Ophthalmology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob W J Collin
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Caroline C W Klaver
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald Roepman
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - B Jeroen Klevering
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
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19
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Singh D, Wang SB, Xia T, Tainsh L, Ghiassi-Nejad M, Xu T, Peng S, Adelman RA, Rizzolo LJ. A biodegradable scaffold enhances differentiation of embryonic stem cells into a thick sheet of retinal cells. Biomaterials 2018; 154:158-168. [DOI: 10.1016/j.biomaterials.2017.10.052] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/23/2017] [Accepted: 10/30/2017] [Indexed: 12/25/2022]
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20
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Affiliation(s)
- Arthur Planul
- Inserm, Institut de la Vision, UMR S968, 75012 Paris, France;,
- Sorbonne Universités, UPMC Université Paris 6, UMR S968, 75012 Paris, France
- CNRS, UMR 7210, 75012 Paris, France
| | - Deniz Dalkara
- Inserm, Institut de la Vision, UMR S968, 75012 Paris, France;,
- Sorbonne Universités, UPMC Université Paris 6, UMR S968, 75012 Paris, France
- CNRS, UMR 7210, 75012 Paris, France
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21
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Brandl C, Schulz HL, Charbel Issa P, Birtel J, Bergholz R, Lange C, Dahlke C, Zobor D, Weber BHF, Stöhr H. Mutations in the Genes for Interphotoreceptor Matrix Proteoglycans, IMPG1 and IMPG2, in Patients with Vitelliform Macular Lesions. Genes (Basel) 2017. [PMID: 28644393 PMCID: PMC5541303 DOI: 10.3390/genes8070170] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A significant portion of patients diagnosed with vitelliform macular dystrophy (VMD) do not carry causative mutations in the classic VMD genes BEST1 or PRPH2. We therefore performed a mutational screen in a cohort of 106 BEST1/PRPH2-negative VMD patients in two genes encoding secreted interphotoreceptor matrix proteoglycans-1 and -2 (IMPG1 and IMPG2). We identified two novel mutations in IMPG1 in two simplex VMD cases with disease onset in their early childhood, a heterozygous p.(Leu238Pro) missense mutation and a homozygous c.807 + 5G > A splice site mutation. The latter induced partial skipping of exon 7 of IMPG1 in an in vitro splicing assay. Furthermore, we found heterozygous mutations including three stop [p.(Glu226*), p.(Ser522*), p.(Gln856*)] and five missense mutations [p.(Ala243Pro), p.(Gly1008Asp), p.(Phe1016Ser), p.(Tyr1042Cys), p.(Cys1077Phe)] in the IMPG2 gene, one of them, p.(Cys1077Phe), previously associated with VMD. Asymptomatic carriers of the p.(Ala243Pro) and p.(Cys1077Phe) mutations show subtle foveal irregularities that could characterize a subclinical stage of disease. Taken together, our results provide further evidence for an involvement of dominant and recessive mutations in IMPG1 and IMPG2 in VMD pathology. There is a remarkable similarity in the clinical appearance of mutation carriers, presenting with bilateral, central, dome-shaped foveal accumulation of yellowish material with preserved integrity of the retinal pigment epithelium (RPE). Clinical symptoms tend to be more severe for IMPG1 mutations.
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Affiliation(s)
- Caroline Brandl
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Regensburg, 93053 Regensburg, Germany;
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
- Lehrstuhl für Genetische Epidemiologie, Universität Regensburg, 93053 Regensburg, Germany
| | - Heidi L. Schulz
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
| | - Peter Charbel Issa
- Department of Ophthalmology, University of Bonn, 53113 Bonn, Germany;
- Oxford Eye Hospital, OUH NHS Foundation Trust and the Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3BD, UK
| | - Johannes Birtel
- Department of Ophthalmology, University of Bonn, 53113 Bonn, Germany;
| | - Richard Bergholz
- Klinik für Augenheilkunde, Charité—Universitätsmedizin Berlin, 10117 Berlin, Germany;
| | - Clemens Lange
- Klinik für Augenheilkunde, Universitätsklinikum Freiburg, Medizinische Fakultät, Albert Ludwigs Universität Freiburg, 79085 Freiburg, Germany;
| | - Claudia Dahlke
- Klinik für Augenheilkunde, Universitätsklinikum Köln, 50937 Köln, Germany;
| | - Ditta Zobor
- Forschungsinstitut für Augenheilkunde, Universitätsklinikum Tübingen, 72076 Tübingen, Germany;
| | - Bernhard H. F. Weber
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
| | - Heidi Stöhr
- Institut für Humangenetik, Universität Regensburg, 93053 Regensburg, Germany; (H.L.S.); (B.H.F.W.)
- Correspondence: ; Tel.: +49-941-944-5424
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22
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Abstract
The recent advances in cell-based therapies for the repair of the pigmented epithelium is providing additional impetus for the translation of photoreceptor transplantation to eventual clinical trials. The prospects for transplantation of photoreceptors as a potential therapy for the treatment of photoreceptor degeneration will depend on successfully addressing many critical issues in preclinical studies. Although most of the studies that have carried out transplants of photoreceptors have primarily used normal mice, there have been recent reports that have also shown some success following transplantation to mouse models of retinitis pigmentosa. However, while these results are promising, there are several key issues that require further investigation in order to better understand the optimum timing for transplantation, given the extensive remodeling of the retina that occurs in late stage disease.
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Ischemic injury leads to extracellular matrix alterations in retina and optic nerve. Sci Rep 2017; 7:43470. [PMID: 28262779 PMCID: PMC5338032 DOI: 10.1038/srep43470] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/25/2017] [Indexed: 01/10/2023] Open
Abstract
Retinal ischemia occurs in a variety of eye diseases. Restrained blood flow induces retinal damage, which leads to progressive optic nerve degeneration and vision loss. Previous studies indicate that extracellular matrix (ECM) constituents play an important role in complex tissues, such as retina and optic nerve. They have great impact on de- and regeneration processes and represent major candidates of central nervous system glial scar formation. Nevertheless, the importance of the ECM during ischemic retina and optic nerve neurodegeneration is not fully understood yet. In this study, we analyzed remodeling of the extracellular glycoproteins fibronectin, laminin, tenascin-C and tenascin-R and the chondroitin sulfate proteoglycans (CSPGs) aggrecan, brevican and phosphacan/RPTPβ/ζ in retinae and optic nerves of an ischemia/reperfusion rat model via quantitative real-time PCR, immunohistochemistry and Western blot. A variety of ECM constituents were dysregulated in the retina and optic nerve after ischemia. Regarding fibronectin, significantly elevated mRNA and protein levels were observed in the retina following ischemia, while laminin and tenascin-C showed enhanced immunoreactivity in the optic nerve after ischemia. Interestingly, CSPGs displayed significantly increased expression levels in the optic nerve. Our study demonstrates a dynamic expression of ECM molecules following retinal ischemia, which strengthens their regulatory role during neurodegeneration.
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Cellular and Molecular Pathology of Age-Related Macular Degeneration: Potential Role for Proteoglycans. J Ophthalmol 2016; 2016:2913612. [PMID: 27563459 PMCID: PMC4983667 DOI: 10.1155/2016/2913612] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/13/2016] [Accepted: 06/26/2016] [Indexed: 12/22/2022] Open
Abstract
Age-related macular degeneration (AMD) is a retinal disease evident after the age of 50 that damages the macula in the centre of retina. It leads to a loss of central vision with retained peripheral vision but eventual blindness occurs in many cases. The initiation site of AMD development is Bruch's membrane (BM) where multiple changes occur including the deposition of plasma derived lipids, accumulation of extracellular debris, changes in cell morphology, and viability and the formation of drusen. AMD manifests as early and late stage; the latter involves cell proliferation and neovascularization in wet AMD. Current therapies target the later hyperproliferative and invasive wet stage whilst none target early developmental stages of AMD. In the lipid deposition disease atherosclerosis modified proteoglycans bind and retain apolipoproteins in the artery wall. Chemically modified trapped lipids are immunogenic and can initiate a chronic inflammatory process manifesting as atherosclerotic plaques and subsequent artery blockages, heart attacks, or strokes. As plasma derived lipoprotein deposits are found in BM in early AMD, it is possible that they arise by a similar process within the macula. In this review we consider aspects of the pathological processes underlying AMD with a focus on the potential role of modifications to secreted proteoglycans being a cause and therefore a target for the treatment of early AMD.
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Hippert C, Graca AB, Pearson RA. Gliosis Can Impede Integration Following Photoreceptor Transplantation into the Diseased Retina. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:579-85. [PMID: 26427462 DOI: 10.1007/978-3-319-17121-0_77] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Retinal degenerations leading to the loss of photoreceptor (PR) cells are a major cause of vision impairment and untreatable blindness. There are few clinical treatments and none can reverse the loss of vision. With the rapid advances in stem cell biology and techniques in cell transplantation, PR replacement by transplantation represents a broad treatment strategy applicable to many types of degeneration. The number of donor cells that integrate into the recipient retina determines transplantation success, yet the degenerating retinae presents a number of barriers that can impede effective integration. Here, we briefly review recent advances in the field of PR transplantation. We then describe how different aspects of gliosis may impact on cell integration efficiency.
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Affiliation(s)
- Claire Hippert
- F. Hoffman La Roche, 124 Grenzacherstrasse, 4070, Basel, Switzerland.
| | - Anna B Graca
- F. Hoffman La Roche, 124 Grenzacherstrasse, 4070, Basel, Switzerland.
| | - Rachael A Pearson
- F. Hoffman La Roche, 124 Grenzacherstrasse, 4070, Basel, Switzerland.
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Faissner A, Reinhard J. The extracellular matrix compartment of neural stem and glial progenitor cells. Glia 2015; 63:1330-49. [DOI: 10.1002/glia.22839] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/25/2015] [Accepted: 03/30/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
| | - Jacqueline Reinhard
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
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Reinhard J, Joachim SC, Faissner A. Extracellular matrix remodeling during retinal development. Exp Eye Res 2015; 133:132-40. [DOI: 10.1016/j.exer.2014.07.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/30/2014] [Accepted: 07/01/2014] [Indexed: 10/25/2022]
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Ishikawa M, Sawada Y, Yoshitomi T. Structure and function of the interphotoreceptor matrix surrounding retinal photoreceptor cells. Exp Eye Res 2015; 133:3-18. [DOI: 10.1016/j.exer.2015.02.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 02/20/2015] [Accepted: 02/20/2015] [Indexed: 12/21/2022]
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The guanine nucleotide exchange factor Vav3 regulates differentiation of progenitor cells in the developing mouse retina. Cell Tissue Res 2014; 359:423-440. [PMID: 25501893 DOI: 10.1007/s00441-014-2050-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
The seven main cell types in the mammalian retina arise from multipotent retinal progenitor cells, a process that is tightly regulated by intrinsic and extrinsic signals. However, the molecular mechanisms that control proliferation, differentiation and cell-fate decisions of retinal progenitor cells are not fully understood yet. Here, we report that the guanine nucleotide exchange factor Vav3, a regulator of Rho-GTPases, is involved in retinal development. We demonstrate that Vav3 is expressed in the mouse retina during the embryonic period. In order to study the role of Vav3 in the developing retina, we generate Vav3-deficient mice. The loss of Vav3 results in an accelerated differentiation of retinal ganglion cells and cone photoreceptors during early and late embryonic development. We provide evidence that more retinal progenitor cells express the late progenitor marker Sox9 in Vav3-deficient mice than in wild-types. This premature differentiation is compensated during the postnatal period and late-born cell types such as bipolar cells and Müller glia display normal numbers. Taken together, our data imply that Vav3 is a regulator of retinal progenitor cell differentiation, thus highlighting a novel role for guanine nucleotide exchange factors in retinogenesis.
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Photoreceptor replacement therapy: Challenges presented by the diseased recipient retinal environment. Vis Neurosci 2014; 31:333-44. [DOI: 10.1017/s0952523814000200] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AbstractVision loss caused by the death of photoreceptors is the leading cause of irreversible blindness in the developed world. Rapid advances in stem cell biology and techniques in cell transplantation have made photoreceptor replacement by transplantation a very plausible therapeutic strategy. These advances include the demonstration of restoration of vision following photoreceptor transplantation and the generation of transplantable populations of donor cells from stem cells. In this review, we present a brief overview of the recent progress in photoreceptor transplantation. We then consider in more detail some of the challenges presented by the degenerating retinal environment that must play host to these transplanted cells, how these may influence transplanted photoreceptor cell integration and survival, and some of the progress in developing strategies to circumnavigate these issues.
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Boon CJ, van de Ven JP, Hoyng CB, den Hollander AI, Klevering BJ. Cuticular drusen: Stars in the sky. Prog Retin Eye Res 2013; 37:90-113. [DOI: 10.1016/j.preteyeres.2013.08.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/14/2013] [Accepted: 08/19/2013] [Indexed: 12/24/2022]
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Keenan TDL, Clark SJ, Unwin RD, Ridge LA, Day AJ, Bishop PN. Mapping the differential distribution of proteoglycan core proteins in the adult human retina, choroid, and sclera. Invest Ophthalmol Vis Sci 2012; 53:7528-38. [PMID: 23074202 DOI: 10.1167/iovs.12-10797] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To examine the presence and distribution of proteoglycan (PG) core proteins in the adult human retina, choroid, and sclera. METHODS Postmortem human eye tissue was dissected into Bruch's membrane/choroid complex, isolated Bruch's membrane, or neurosensory retina. PGs were extracted and partially purified by anion exchange chromatography. Trypsinized peptides were analyzed by tandem mass spectrometry and PG core proteins identified by database search. The distribution of PGs was examined by immunofluorescence microscopy on human macular tissue sections. RESULTS The basement membrane PGs perlecan, agrin, and collagen-XVIII were identified in the human retina, and were present in the internal limiting membrane, blood vessel walls, and Bruch's membrane. The hyalectans versican and aggrecan were also detected. Versican was identified in Bruch's membrane, while aggrecan was distributed throughout the retina, choroid, and sclera. The cartilage link protein HAPLN1 was abundant in the interphotoreceptor matrix and sclera, while HAPLN4 (brain link protein 2) was found throughout the retina and choroid. The small leucine-rich repeat PG (SLRP) family members biglycan, decorin, fibromodulin, lumican, mimecan, opticin, and prolargin were present, with different patterns of distribution in the retina, choroid, and sclera. CONCLUSIONS A combination of proteomics and immunohistochemistry approaches has provided for the first time a comprehensive analysis of the presence and distribution of PG core proteins throughout the human retina, choroid, and sclera. This complements our knowledge of glycosaminoglycan chain distribution in the human eye, and has important implications for understanding the structure and functional regulation of the eye in health and disease.
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Affiliation(s)
- Tiarnan D L Keenan
- Centre for Ophthalmology and Vision Research, Institute of Human Development, Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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Mettu PS, Wielgus AR, Ong SS, Cousins SW. Retinal pigment epithelium response to oxidant injury in the pathogenesis of early age-related macular degeneration. Mol Aspects Med 2012; 33:376-98. [PMID: 22575354 DOI: 10.1016/j.mam.2012.04.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 04/14/2012] [Indexed: 01/06/2023]
Abstract
Age-related macular degeneration (AMD) represents the leading cause of vision loss in the elderly. Accumulation of lipid- and protein-rich deposits under the retinal pigment epithelium (RPE) heralds the onset of early AMD, but the pathogenesis of subretinal deposit formation is poorly understood. Numerous hypothetical models of deposit formation have been proposed, including hypotheses for a genetic basis, choroidal hypoperfusion, abnormal barrier formation, and lysosomal failure. This review explore the RPE injury hypothesis, characterized by three distinct stages (1) Initial RPE oxidant injury, caused by any number of endogenous or exogenous oxidants, results in extrusion of cell membrane "blebs," together with decreased activity of matrix metalloproteinases (MMPs), promoting bleb accumulation under the RPE as basal laminar deposits (BLD). (2) RPE cells are subsequently stimulated to increase synthesis of MMPs and other molecules responsible for extracellular matrix turnover (i.e., producing decreased collagen), affecting both RPE basement membrane and Bruchs membrane (BrM). This process leads to progression of BLD into basal linear deposits (BLinD) and drusen by admixture of blebs into BrM, followed by the formation of new basement membrane under the RPE to trap these deposits within BrM. We postulate that various hormones and other plasma-derived molecules related to systemic health cofactors are implicated in this second stage. (3) Finally, macrophages are recruited to sites of RPE injury and deposit formation. The recruitment of nonactivated or scavenging macrophages may remove deposits without further injury, while the recruitment of activated or reparative macrophages, through the release of inflammatory mediators, growth factors, or other substances, may promote complications and progression to the late forms of the disease.
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Affiliation(s)
- Priyatham S Mettu
- Duke Center for Macular Diseases, Duke Eye Center, Durham, NC 27710, USA
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Chen LF, FitzGibbon T, He JR, Yin ZQ. Localization and developmental expression patterns of CSPG-cs56 (aggrecan) in normal and dystrophic retinas in two rat strains. Exp Neurol 2012; 234:488-98. [PMID: 22306080 DOI: 10.1016/j.expneurol.2012.01.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 01/16/2012] [Accepted: 01/19/2012] [Indexed: 10/14/2022]
Abstract
Proteoglycans have a number of important functions in the central nervous system. Aggrecan (hyaluronan-binding proteoglycan, CSPG-cs56) is found in the extracellular matrix of cartilage as well as in the developing brain. We compared the postnatal distribution of CSPG-cs56 in Long Evans (LE) and Royal College of Surgeons (RCS) rat retinas to determine if this proteoglycan played a role in the development of dystrophic retinas. CSPG-cs56 expression was examined in rat retinas aged between birth (postnatal day 0, P0) and P150 using immunofluorescence and Western-blots. Immunofluorescence was quantified using ImageJ. GFAP staining was used to compare Müller cell labeling and the distribution of CSPG-cs56. Both rat strains showed a significant rise in total retinal CSPG-cs56 between P0 and P21; values peaked on P21 in LE rats and P14 in RCS rats. CSPG-cs56 then significantly decreased to lower levels (P35) in both strains before reaching significantly higher levels by P90-P150. CSPG-cs56 positive staining was present in the ganglion cell layer at birth and clear layering of the inner plexiform layer was seen between P7 and P21 due to dendritic staining of retinal ganglion cells. Staining was less intense and diffuse within the outer plexiform over a similar time-course. Light CSPG-cs56 labeling in the region of the outer segments was present at (P14) and became more intense as the retina approached maturity. CSPG-cs56 in the outer segments was the main contributor to the higher expression in older animals. Substantial differences in CSPG-cs56 labeling were not seen between LE and RCS rats. There was no evidence to suggest that Müller cells were the source of CSPG-cs56 in either rat strain, although their staining distributions had a degree of overlap. The lack of significant differences between LE and RCS rats indicates that CSPG-cs56 may not be involved in the degenerative process or the reorganization of the RCS rat retina. We suggest that the main role of CPSG-cs56 is to maintain retinal ganglion cell dendritic structure in the inner plexiform layer and is closely related to providing adequate support and flexibility for the photoreceptor outer segments, which is necessary to maintain their function.
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Affiliation(s)
- Li-Feng Chen
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China.
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Clark SJ, Keenan TDL, Fielder HL, Collinson LJ, Holley RJ, Merry CLR, van Kuppevelt TH, Day AJ, Bishop PN. Mapping the differential distribution of glycosaminoglycans in the adult human retina, choroid, and sclera. Invest Ophthalmol Vis Sci 2011; 52:6511-21. [PMID: 21746802 DOI: 10.1167/iovs.11-7909] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE. To map the distribution of different classes of glycosaminoglycans (GAGs) in the healthy human retina, choroid, and sclera. METHODS. Frozen tissue sections were made from adult human donor eyes. The GAG chains of proteoglycans (PGs) were detected with antibodies directed against various GAG structures (either directly or after pretreatment with GAG-degrading enzymes); hyaluronan (HA) was detected using biotinylated recombinant G1-domain of human versican. The primary detection reagents were identified with FITC-labeled probes and analyzed by fluorescence microscopy. RESULTS. Heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), and HA were present throughout the retina and choroid, but keratan sulfate (KS) was detected only in the sclera. HS labeling was particularly strong in basement membrane-containing structures, the nerve fiber layer (NFL), and retinal pigment epithelium (RPE)-for example, intense staining was seen with an antibody that binds strongly to sequences containing 3-O-sulfation in the internal limiting membrane (ILM) and in the basement membrane of blood vessels. Unsulfated CS was seen throughout the retina, particularly in the ILM and interphotoreceptor matrix (IPM) with 6-O-sulfated CS also prominent in the IPM. There was labeling for DS throughout the retina and choroid, especially in the NFL, ganglion cell layer, and blood vessels. CONCLUSIONS. The detection of GAG chains with specific probes and fluorescence microscopy provides for the first time a detailed analysis of their compartmentalization in the human retina, by both GAG chain type and sulfation pattern. This reference map provides a basis for understanding the functional regulation of GAG-binding proteins in health and disease processes.
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de Zavalía N, Plano SA, Fernandez DC, Lanzani MF, Salido E, Belforte N, Sarmiento MIK, Golombek DA, Rosenstein RE. Effect of experimental glaucoma on the non-image forming visual system. J Neurochem 2011; 117:904-14. [DOI: 10.1111/j.1471-4159.2011.07260.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Manifestations ophtalmologiques de la maladie de Morquio. J Fr Ophtalmol 2010; 33:617-22. [DOI: 10.1016/j.jfo.2010.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Accepted: 08/28/2010] [Indexed: 11/18/2022]
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Nishiguchi KM, Kataoka K, Kachi S, Komeima K, Terasaki H. Regulation of pathologic retinal angiogenesis in mice and inhibition of VEGF-VEGFR2 binding by soluble heparan sulfate. PLoS One 2010; 5:e13493. [PMID: 20975989 PMCID: PMC2958111 DOI: 10.1371/journal.pone.0013493] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 09/24/2010] [Indexed: 12/25/2022] Open
Abstract
Development of the retinal vascular network is strictly confined within the neuronal retina, allowing the intraocular media to be optically transparent. However, in retinal ischemia, pro-angiogenic factors (including vascular endothelial growth factor-A, VEGF-A) induce aberrant guidance of retinal vessels into the vitreous. Here, we show that the soluble heparan sulfate level in murine intraocular fluid is high particularly during ocular development. When the eyes of young mice with retinal ischemia were treated with heparan sulfate-degrading enzyme, the subsequent aberrant angiogenesis was greatly enhanced compared to PBS-injected contralateral eyes; however, increased angiogenesis was completely antagonized by simultaneous injection of heparin. Intraocular injection of heparan sulfate or heparin alone in these eyes resulted in reduced neovascularization. In cell cultures, the porcine ocular fluid suppressed the dose-dependent proliferation of human umbilical vein endothelial cells (HUVECs) mediated by VEGF-A. Ocular fluid and heparin also inhibited the migration and tube formation by these cells. The binding of VEGF-A and HUVECs was reduced under a high concentration of heparin or ocular fluid compared to lower concentrations of heparin. In vitro assays demonstrated that the ocular fluid or soluble heparan sulfate or heparin inhibited the binding of VEGF-A and immobilized heparin or VEGF receptor 2 but not VEGF receptor 1. The recognition that the high concentration of soluble heparan sulfate in the ocular fluid allows it to serve as an endogenous inhibitor of aberrant retinal vascular growth provides a platform for modulating heparan sulfate/heparin levels to regulate angiogenesis.
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Affiliation(s)
- Koji M Nishiguchi
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
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Bandah-Rozenfeld D, Collin RWJ, Banin E, van den Born LI, Coene KLM, Siemiatkowska AM, Zelinger L, Khan MI, Lefeber DJ, Erdinest I, Testa F, Simonelli F, Voesenek K, Blokland EAW, Strom TM, Klaver CCW, Qamar R, Banfi S, Cremers FPM, Sharon D, den Hollander AI. Mutations in IMPG2, encoding interphotoreceptor matrix proteoglycan 2, cause autosomal-recessive retinitis pigmentosa. Am J Hum Genet 2010; 87:199-208. [PMID: 20673862 DOI: 10.1016/j.ajhg.2010.07.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/25/2010] [Accepted: 07/11/2010] [Indexed: 11/17/2022] Open
Abstract
Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal diseases caused by progressive degeneration of the photoreceptor cells. Using autozygosity mapping, we identified two families, each with three affected siblings sharing large overlapping homozygous regions that harbored the IMPG2 gene on chromosome 3. Sequence analysis of IMPG2 in the two index cases revealed homozygous mutations cosegregating with the disease in the respective families: three affected siblings of Iraqi Jewish ancestry displayed a nonsense mutation, and a Dutch family displayed a 1.8 kb genomic deletion that removes exon 9 and results in the absence of seven amino acids in a conserved SEA domain of the IMPG2 protein. Transient transfection of COS-1 cells showed that a construct expressing the wild-type SEA domain is properly targeted to the plasma membrane, whereas the mutant lacking the seven amino acids appears to be retained in the endoplasmic reticulum. Mutation analysis in ten additional index cases that were of Dutch, Israeli, Italian, and Pakistani origin and had homozygous regions encompassing IMPG2 revealed five additional mutations; four nonsense mutations and one missense mutation affecting a highly conserved phenylalanine residue. Most patients with IMPG2 mutations showed an early-onset form of RP with progressive visual-field loss and deterioration of visual acuity. The patient with the missense mutation, however, was diagnosed with maculopathy. The IMPG2 gene encodes the interphotoreceptor matrix proteoglycan IMPG2, which is a constituent of the interphotoreceptor matrix. Our data therefore show that mutations in a structural component of the interphotoreceptor matrix can cause arRP.
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Affiliation(s)
- Dikla Bandah-Rozenfeld
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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Ali SAM, Hosaka YZ, Uehara M. Spatiotemporal distribution of chondroitin sulfate proteoglycans in the developing mouse retina and optic nerve. J Vet Med Sci 2010; 73:13-8. [PMID: 20716860 DOI: 10.1292/jvms.10-0201] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to determine the distribution of chondroitin sulfate proteoglycans in the mouse retina and optic nerve of the prenatal and postnatal mouse by immunohistochemistry. At embryonic day (E) 18, chondroitin-4-sulfate (C4S), chondroitin-6-sulfate (C6S) and biglycan were detected in the retina and optic nerve. However, aggrecan was seen in the retina but not in the optic nerve. At postnatal day (P) 7, aggrecan and biglycan were clearly observed in the optic nerve, inner nuclear layer and ganglion cell layer and diffuse in the outer retina. C4S diffusely distributed in the retina and optic nerve, but C6S was mainly confined to the photoreceptor layer and optic nerve sheath. At P42, biglycan showed diffuse distribution in the retina and optic nerve with intense staining in nerve-fiber rich layers. Aggrecan showed weak staining at the inner plexiform layer with higher density in the outer and inner nuclear layers, outer plexiform layer and ganglion cell layer. Both C4S and C6S were detected in the optic nerve and retina, but C6S showed strong immunostaining in the photoreceptor layer. The distributions of these proteoglycans with respect of time course during development of the retina and optic nerve suggest that they may have unique or overlapping roles in development and maintenance of the retina and optic nerve.
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Affiliation(s)
- Safwat Ali Mohamed Ali
- Laboratory of Basic Veterinary Science, United Graduate School of Veterinary Science, Yamaguchi University, Japan
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Bhatia B, Singhal S, Jayaram H, Khaw PT, Limb GA. Adult retinal stem cells revisited. Open Ophthalmol J 2010; 4:30-8. [PMID: 20871757 PMCID: PMC2945004 DOI: 10.2174/1874364101004010030] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 01/22/2010] [Accepted: 04/12/2010] [Indexed: 01/12/2023] Open
Abstract
Recent advances in retinal stem cell research have raised the possibility that these cells have the potential to be used to repair or regenerate diseased retina. Various cell sources for replacement of retinal neurons have been identified, including embryonic stem cells, the adult ciliary epithelium, adult Müller stem cells and induced pluripotent stem cells (iPS). However, the true stem cell nature of the ciliary epithelium and its possible application in cell therapies has now been questioned, leaving other cell sources to be carefully examined as potential candidates for such therapies. The need for identification of the ontogenetic state of grafted stem cells in order to achieve their successful integration into the murine retina has been recognized. However, it is not known whether the same requirements may apply to achieve transplant cell integration into the adult human eye. In addition, the existence of natural barriers for stem cell transplantation, including microglial accumulation and abnormal extracellular matrix deposition have been demonstrated, suggesting that several obstacles need to be overcome before such therapies may be implemented. This review addresses recent scientific developments in the field and discusses various strategies that may be potentially used to design cell based therapies to treat human retinal disease.
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Affiliation(s)
- Bhairavi Bhatia
- Division of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology and Moorfields Eye Hospital, London, UK
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Bringmann A, Iandiev I, Pannicke T, Wurm A, Hollborn M, Wiedemann P, Osborne NN, Reichenbach A. Cellular signaling and factors involved in Müller cell gliosis: neuroprotective and detrimental effects. Prog Retin Eye Res 2009; 28:423-51. [PMID: 19660572 DOI: 10.1016/j.preteyeres.2009.07.001] [Citation(s) in RCA: 506] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Müller cells are active players in normal retinal function and in virtually all forms of retinal injury and disease. Reactive Müller cells protect the tissue from further damage and preserve tissue function by the release of antioxidants and neurotrophic factors, and may contribute to retinal regeneration by the generation of neural progenitor/stem cells. However, Müller cell gliosis can also contribute to neurodegeneration and impedes regenerative processes in the retinal tissue by the formation of glial scars. This article provides an overview of the neuroprotective and detrimental effects of Müller cell gliosis, with accounts on the cellular signal transduction mechanisms and factors which are implicated in Müller cell-mediated neuroprotection, immunomodulation, regulation of Müller cell proliferation, upregulation of intermediate filaments, glial scar formation, and the generation of neural progenitor/stem cells. A proper understanding of the signaling mechanisms implicated in gliotic alterations of Müller cells is essential for the development of efficient therapeutic strategies that increase the supportive/protective and decrease the destructive roles of gliosis.
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Affiliation(s)
- Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103 Leipzig, Germany.
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Bringmann A, Wiedemann P. Involvement of Müller glial cells in epiretinal membrane formation. Graefes Arch Clin Exp Ophthalmol 2009; 247:865-83. [PMID: 19415318 DOI: 10.1007/s00417-009-1082-x] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 02/10/2009] [Accepted: 04/06/2009] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Proliferative retinopathies are considered to represent maladapted retinal wound repair processes driven by growth factor- and cytokine-induced overstimulation of proliferation, migration, extracellular matrix production and contraction of retinal cells. The formation of neovascular membranes represents an attempt to reoxygenize non-perfused retinal areas. Müller glial cells play a crucial role in the pathogenesis of proliferative retinopathies. This review summarizes the present knowledge regarding the role of Müller cells in periretinal membrane formation, especially in the early steps of epiretinal membrane formation, which involve an interaction of inflammatory and glial cells, and gives a survey of the factors which are suggested to be implicated in the induction of Müller cell gliosis and proliferation. CONCLUSIONS Alterations in the membrane conductance of Müller cells suggest that Müller cells may alter their phenotype into progenitor-like cells in the course of proliferative retinopathies; transdifferentiated Müller cells may have great impact for the development of new cell-based therapies.
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Affiliation(s)
- Andreas Bringmann
- Department of Ophthalmology, Faculty of Medicine, University of Leipzig, Eye Hospital, Leipzig, Germany.
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The spectrum of phenotypes caused by variants in the CFH gene. Mol Immunol 2009; 46:1573-94. [PMID: 19297022 DOI: 10.1016/j.molimm.2009.02.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Revised: 02/09/2009] [Accepted: 02/11/2009] [Indexed: 12/24/2022]
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Viscoelastic agent retention and failed macular hole surgery. Retin Cases Brief Rep 2009; 3:77-9. [PMID: 25390847 DOI: 10.1097/icb.0b013e318158de4f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe the retention of a viscoelastic agent as a possible cause of failed macular hole surgery. METHODS AND PATIENTS Three consecutive patients underwent macular hole surgery. A bubble of viscoelastic agent was used to prevent contact between indocyanine green dye and retinal pigment epithelium cells. RESULTS Macular hole repair failed in all three cases. After a second surgery the holes closed successfully. CONCLUSION The use of a dispersive viscoelastic agent to avoid indocyanine green toxicity in macular hole surgery may prevent the closure of the hole.
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Tucker B, Klassen H, Yang L, Chen DF, Young MJ. Elevated MMP Expression in the MRL Mouse Retina Creates a Permissive Environment for Retinal Regeneration. Invest Ophthalmol Vis Sci 2008; 49:1686-95. [PMID: 18385092 DOI: 10.1167/iovs.07-1058] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
PURPOSE The MRL/MpJ (healer) mouse is an established model for autoimmune studies and was recently identified as having a profound ability to undergo scarless regeneration of the tissue in the ear and heart. This regenerative capacity has been linked to elevated matrix metalloproteinase (MMP)-2 and -9 expression, giving this mouse the ability to degrade and remove inhibitory basement membrane molecules. Although elevated MMP expression has been reported in somatic tissues in this strain, little is known about MMP expression and the response to injury in the MRL/MpJ mouse retina. The purpose of this study was to investigate whether increased MMP expression and subsequent decreased inhibitory extracellular matrix molecule deposition in the MRL/MpJ mouse retina produces a permissive regenerative environment. METHODS Experiments were performed using 3- to 4-week-old MRL/MpJ, retinal degenerative (rd1), and C57BL/6 (wild-type) mice. Western blotting, oligo-microarray, and immunohistochemical analyses were used to determine the level and location of MMP and extracellular matrix (ECM) protein expression. Retinal responses to injury were modeled by retinal detachment in vivo and in retinal explantation in vitro. The capacity of the retinal environment to support photoreceptor cell migration, integration, or regeneration was analyzed using hematoxylin-eosin, immunohistochemical staining, and cell counting. RESULTS Compared with C57BL/6J animals, MRL/MpJ mice exhibit elevated levels of MMP-2, -9, and -14 and decreased levels of the inhibitory proteins neurocan and CD44 within the retina. Although similar increases in MMP-2, -9, and CD44s (CD44 degradation product) were observed in the rd1 retina, elevated levels of the inhibitory ECM molecules (neurocan and CD44) remained. Thus, the MRL retinal environment, which expresses lower levels of inhibitory ECM molecules after injury, was more conducive to regeneration and enhanced photoreceptor integration in vitro than C57BL/6J or rd1 controls. CONCLUSIONS The MRL mouse retina shows elevated MMP expression and decreased levels of scar-related inhibitory molecules, which leads to a retinal environment that is more permissive for neural regeneration and cell integration after in vitro retinal explantation.
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Affiliation(s)
- Budd Tucker
- Department of Ophthalmology, Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114, USA.
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Singhal S, Lawrence JM, Bhatia B, Ellis JS, Kwan AS, Macneil A, Luthert PJ, Fawcett JW, Perez MT, Khaw PT, Limb GA. Chondroitin sulfate proteoglycans and microglia prevent migration and integration of grafted Müller stem cells into degenerating retina. Stem Cells 2008; 26:1074-82. [PMID: 18218817 DOI: 10.1634/stemcells.2007-0898] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
At present, there are severe limitations to the successful migration and integration of stem cells transplanted into the degenerated retina to restore visual function. This study investigated the potential role of chondroitin sulfate proteoglycans (CSPGs) and microglia in the migration of human Müller glia with neural stem cell characteristics following subretinal injection into the Lister hooded (LH) and Royal College of Surgeons (RCS) rat retinae. Neonate LH rat retina showed minimal baseline microglial accumulation (CD68-positive cells) that increased significantly 2 weeks after transplantation (p < .001), particularly in the ganglion cell layer (GCL) and inner plexiform layer. In contrast, nontransplanted 5-week-old RCS rat retina showed considerable baseline microglial accumulation in the outer nuclear layer (ONL) and photoreceptor outer segment debris zone (DZ) that further increased (p < .05) throughout the retina 2 weeks after transplantation. Marked deposition of the N-terminal fragment of CSPGs, as well as neurocan and versican, was observed in the DZ of 5-week-old RCS rat retinae, which contrasted with the limited expression of these proteins in the GCL of the adult and neonate LH rat retinae. Staining for CSPGs and CD68 revealed colocalization of these two molecules in cells infiltrating the ONL and DZ of the degenerating RCS rat retina. Enhanced immune suppression with oral prednisolone and intraperitoneal injections of indomethacin caused a reduction in the number of microglia but did not facilitate Müller stem cell migration. However, injection of cells with chondroitinase ABC combined with enhanced immune suppression caused a dramatic increase in the migration of Müller stem cells into all the retinal cell layers. These observations suggest that both microglia and CSPGs constitute a barrier for stem cell migration following transplantation into experimental models of retinal degeneration and that control of matrix deposition and the innate microglial response to neural retina degeneration may need to be addressed when translating cell-based therapies to treat human retinal disease.
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Affiliation(s)
- Shweta Singhal
- Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom
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Guilarducci-Ferraz CVV, da Silva GM, Torres PMM, Dos Santos AA, de Araújo EG. The increase in retinal cells proliferation induced by FGF2 is mediated by tyrosine and PI3 kinases. Neurochem Res 2007; 33:754-64. [PMID: 17940890 DOI: 10.1007/s11064-007-9491-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Accepted: 08/28/2007] [Indexed: 11/30/2022]
Abstract
Since 1973, multiple effects of basic fibroblast growth factor have been described in a large number of cells. These effects include proliferation, survival and differentiation. The aim of this work was to study the intracellular pathways involved in the basic fibroblast growth factor (FGF2) effect on rat retinal cells proliferation in vitro. Our data show that treatment with FGF2 increases proliferation in a concentration- and time-dependent manner. The effect of 25 ng/ml FGF2 was blocked by 10 microM genistein, a tyrosine kinase inhibitor and by 25 microM LY294002, a PI3 kinase inhibitor. The concomitant treatment with 0.3 microM chelerythrine chloride, a protein kinase C inhibitor, and 6.25 microM LY294002 also inhibited the effect of FGF2. Our results suggest that the proliferative effect of FGF2 on retinal cell cultures involves the activation of distinct kinases.
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Affiliation(s)
- Carla Valéria Vieira Guilarducci-Ferraz
- Programa de Neuroimunologia, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Caxia Postal 100180, CEP 24.001-970 Niteroi, RJ, Brazil
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Krilleke D, DeErkenez A, Schubert W, Giri I, Robinson GS, Ng YS, Shima DT. Molecular mapping and functional characterization of the VEGF164 heparin-binding domain. J Biol Chem 2007; 282:28045-56. [PMID: 17626017 DOI: 10.1074/jbc.m700319200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The longer splice isoforms of vascular endothelial growth factor-A (VEGF-A), including mouse VEGF164, contain a highly basic heparin-binding domain (HBD), which imparts the ability of these isoforms to be deposited in the heparan sulfate-rich extracellular matrix and to interact with the prototype sulfated glycosaminoglycan, heparin. The shortest isoform, VEGF120, lacks this highly basic domain and is freely diffusible upon secretion. Although the HBD has been attributed significant relevance to VEGF-A biology, the molecular determinants of the heparin-binding site are unknown. We used site-directed mutagenesis to identify amino acid residues that are critical for heparin binding activity of the VEGF164 HBD. We focused on basic residues and found Arg-13, Arg-14, and Arg-49 to be critical for heparin binding and interaction with extracellular matrix in tissue samples. We also examined the cellular and biochemical consequences of abolishing heparin-binding function, measuring the ability of the mutants to interact with VEGF receptors, induce endothelial cell gene expression, and trigger microvessel outgrowth. Induction of tissue factor expression, vessel outgrowth, and binding to VEGFR2 were unaffected by the HBD mutations. In contrast, the HBD mutants showed slightly decreased binding to the NRP1 (neuropilin-1) receptor, and analyses suggested the heparin and NRP1 binding sites to be distinct but overlapping. Finally, mutations that affect the heparin binding activity also led to an unexpected reduction in the affinity of VEGF164 binding specifically to VEGFR1. This finding provides a potential basis for previous observations suggesting enhanced potency of VEGF164 versus VEGF120 in VEGFR1-mediated signaling in inflammatory cells.
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