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Basu B, Karwatka M, China B, McKibbin M, Khan K, Inglehearn CF, Ladbury JE, Johnson CA. Glycogen myophosphorylase loss causes increased dependence on glucose in iPSC-derived retinal pigment epithelium. J Biol Chem 2024; 300:107569. [PMID: 39009342 PMCID: PMC11342771 DOI: 10.1016/j.jbc.2024.107569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 06/07/2024] [Accepted: 06/27/2024] [Indexed: 07/17/2024] Open
Abstract
Loss of glycogen myophosphorylase (PYGM) expression results in an inability to break down muscle glycogen, leading to McArdle disease-an autosomal recessive metabolic disorder characterized by exercise intolerance and muscle cramps. While previously considered relatively benign, this condition has recently been associated with pattern dystrophy in the retina, accompanied by variable sight impairment, secondary to retinal pigment epithelial (RPE) cell involvement. However, the pathomechanism of this condition remains unclear. In this study, we generated a PYGM-null induced pluripotent stem cell line and differentiated it into mature RPE to examine structural and functional defects, along with metabolite release into apical and basal media. Mutant RPE exhibited normal photoreceptor outer segment phagocytosis but displayed elevated glycogen levels, reduced transepithelial resistance, and increased cytokine secretion across the epithelial layer compared to isogenic WT controls. Additionally, decreased expression of the visual cycle component, RDH11, encoding 11-cis-retinol dehydrogenase, was observed in PYGM-null RPE. While glycolytic flux and oxidative phosphorylation levels in PYGM-null RPE were near normal, the basal oxygen consumption rate was increased. Oxygen consumption rate in response to physiological levels of lactate was significantly greater in WT than PYGM-null RPE. Inefficient lactate utilization by mutant RPE resulted in higher glucose dependence and increased glucose uptake from the apical medium in the presence of lactate, suggesting a reduced capacity to spare glucose for photoreceptor use. Metabolic tracing confirmed slower 13C-lactate utilization by PYGM-null RPE. These findings have key implications for retinal health since they likely underlie the vision impairment in individuals with McArdle disease.
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Affiliation(s)
- Basudha Basu
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Magdalena Karwatka
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Becky China
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Martin McKibbin
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Department of Ophthalmology, St James's University Hospital, Leeds, UK
| | - Kamron Khan
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Chris F Inglehearn
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - John E Ladbury
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Colin A Johnson
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK.
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2
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Layer PG. In a century from agitated cells to human organoids. J Neurosci Methods 2024; 405:110083. [PMID: 38387805 DOI: 10.1016/j.jneumeth.2024.110083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/09/2024] [Accepted: 02/18/2024] [Indexed: 02/24/2024]
Abstract
Reaching back more than a century, suspension cultures have provided major insights into processes of histogenesis; e.g., cell communication, distinction of self/nonself, cell sorting and cell adhesion. Besides studies on lower animals, the vertebrate retina served as excellent reaggregate model to analyze 3D reconstruction of a complex neural laminar tissue. Methodologically, keeping cells under suspension is essential to achieve tissue organisation in vitro; thereby, the environmental conditions direct the emergent histotypic particulars. Recent progress in regenerative medicine is based to a large extent on human induced pluripotent stem cells (hiPSCs), which are cultured under suspension. Following their genetically directed differentiation into various histologic 3D structures, organoids provide excellent multipurpose in vitro assay models, as well as tissues for repair transplantations. Historically, a nearly fully laminated retinal spheroid from avian embryos was achieved already in 1984, foreshadowing the potential of culturing stem cells under suspension for tissue reconstruction purposes.
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Affiliation(s)
- Paul Gottlob Layer
- Technical University of Darmstadt, Developmental Biology & Neurogenetics, Schnittspahnstrasse 13, Darmstadt 64297, Germany.
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3
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Deletion of the Pedf gene leads to inflammation, photoreceptor loss and vascular disturbances in the retina. Exp Eye Res 2022; 222:109171. [PMID: 35809620 DOI: 10.1016/j.exer.2022.109171] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/25/2022] [Accepted: 06/30/2022] [Indexed: 11/24/2022]
Abstract
Retinal diseases are often accompanied by inflammation, vascular abnormalities, and neurodegeneration that decrease vision. Treatment with exogenous PEDF is widely shown to alleviate these conditions leading us to hypothesize that loss of function of the PEDF gene disrupts these pathways and leads to visual loss. Measurements were carried out by detailed phenotyping of PEDF null mice to assess expression of immunomodulators, glia activation, systemic inflammation, vascular disturbances, and visual sensitivity often associated with retinal pathologies. With a deletion of the Pedf gene, there was increased expression of several immune modulators in Pedf-/- retinas and serum with IL-2 and GM-CSF upregulated in both. Increases in retina glia activation and macrophage infiltration, levels of serum c-reactive protein (CRP), numbers of white and red blood cells and platelets and decreased blood glucose levels were all features associated with PEDF null mice. With PEDF gene deletion, there was also a notable increase in apoptosis in early developing retinas (PN3), reduced thickness of the photoreceptor layer, swelling of the inner plexiform layer, reduced retinal sensitivity and steady-state reduced activation of Erk and Akt, two signaling pathways used by PEDF. There is a substantial body of animal data emphasizing utility of PEDF treatment in homeostatic regulation of retinal diseases, including diabetic retinopathy and age-related macular degeneration but there is little agreement or evidence on the role of endogenous PEDF in retinal diseases. Our findings strongly support the concept that a deletion of the PEDF gene makes the retina vulnerable to diseases, and argue that endogenous PEDF plays a critical role in limiting pathological events in the retina.
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Self-Organization of the Retina during Eye Development, Retinal Regeneration In Vivo, and in Retinal 3D Organoids In Vitro. Biomedicines 2022; 10:biomedicines10061458. [PMID: 35740479 PMCID: PMC9221005 DOI: 10.3390/biomedicines10061458] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/16/2022] [Accepted: 06/18/2022] [Indexed: 11/23/2022] Open
Abstract
Self-organization is a process that ensures histogenesis of the eye retina. This highly intricate phenomenon is not sufficiently studied due to its biological complexity and genetic heterogeneity. The review aims to summarize the existing central theories and ideas for a better understanding of retinal self-organization, as well as to address various practical problems of retinal biomedicine. The phenomenon of self-organization is discussed in the spatiotemporal context and illustrated by key findings during vertebrate retina development in vivo and retinal regeneration in amphibians in situ. Described also are histotypic 3D structures obtained from the disaggregated retinal progenitor cells of birds and retinal 3D organoids derived from the mouse and human pluripotent stem cells. The review highlights integral parts of retinal development in these conditions. On the cellular level, these include competence, differentiation, proliferation, apoptosis, cooperative movements, and migration. On the physical level, the focus is on the mechanical properties of cell- and cell layer-derived forces and on the molecular level on factors responsible for gene regulation, such as transcription factors, signaling molecules, and epigenetic changes. Finally, the self-organization phenomenon is discussed as a basis for the production of retinal organoids, a promising model for a wide range of basic scientific and medical applications.
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5
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Rizzolo LJ, Nasonkin IO, Adelman RA. Retinal Cell Transplantation, Biomaterials, and In Vitro Models for Developing Next-generation Therapies of Age-related Macular Degeneration. Stem Cells Transl Med 2022; 11:269-281. [PMID: 35356975 PMCID: PMC8968686 DOI: 10.1093/stcltm/szac001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 12/02/2021] [Indexed: 11/12/2022] Open
Abstract
Retinal pigment epithelium (RPE) cells grown on a scaffold, an RPE patch, have potential to ameliorate visual impairment in a limited number of retinal degenerative conditions. This tissue-replacement therapy is suited for age-related macular degeneration (AMD), and related diseases. RPE cells must be transplanted before the disease reaches a point of no return, represented by the loss of photoreceptors. Photoreceptors are specialized, terminally differentiated neurosensory cells that must interact with RPE's apical processes to be functional. Human photoreceptors are not known to regenerate. On the RPE's basal side, the RPE transplant must induce the reformation of the choriocapillaris, thereby re-establishing the outer blood-retinal barrier. Because the scaffold is positioned between the RPE and choriocapillaris, it should ideally degrade and be replaced by the natural extracellular matrix that separates these tissues. Besides biodegradable, the scaffolds need to be nontoxic, thin enough to not affect the focal length of the eye, strong enough to survive the transplant procedure, yet flexible enough to conform to the curvature of the retina. The challenge is patients with progressing AMD treasure their remaining vision and fear that a risky surgical procedure will further degrade their vision. Accordingly, clinical trials only treat eyes with severe impairment that have few photoreceptors to interact with the transplanted patch. Although safety has been demonstrated, the cell-replacement mechanism and efficacy remain difficult to validate. This review covers the structure of the retina, the pathology of AMD, the limitations of cell therapy approaches, and the recent progress in developing retinal therapies using biomaterials.
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Affiliation(s)
- Lawrence J Rizzolo
- Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, USA
- Department of Surgery, Yale University, New Haven, CT, USA
| | | | - Ron A Adelman
- Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, USA
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6
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Singh RK, Nasonkin IO. Limitations and Promise of Retinal Tissue From Human Pluripotent Stem Cells for Developing Therapies of Blindness. Front Cell Neurosci 2020; 14:179. [PMID: 33132839 PMCID: PMC7513806 DOI: 10.3389/fncel.2020.00179] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/25/2020] [Indexed: 12/13/2022] Open
Abstract
The self-formation of retinal tissue from pluripotent stem cells generated a tremendous promise for developing new therapies of retinal degenerative diseases, which previously seemed unattainable. Together with use of induced pluripotent stem cells or/and CRISPR-based recombineering the retinal organoid technology provided an avenue for developing models of human retinal degenerative diseases "in a dish" for studying the pathology, delineating the mechanisms and also establishing a platform for large-scale drug screening. At the same time, retinal organoids, highly resembling developing human fetal retinal tissue, are viewed as source of multipotential retinal progenitors, young photoreceptors and just the whole retinal tissue, which may be transplanted into the subretinal space with a goal of replacing patient's degenerated retina with a new retinal "patch." Both approaches (transplantation and modeling/drug screening) were projected when Yoshiki Sasai demonstrated the feasibility of deriving mammalian retinal tissue from pluripotent stem cells, and generated a lot of excitement. With further work and testing of both approaches in vitro and in vivo, a major implicit limitation has become apparent pretty quickly: the absence of the uniform layer of Retinal Pigment Epithelium (RPE) cells, which is normally present in mammalian retina, surrounds photoreceptor layer and develops and matures first. The RPE layer polarize into apical and basal sides during development and establish microvilli on the apical side, interacting with photoreceptors, nurturing photoreceptor outer segments and participating in the visual cycle by recycling 11-trans retinal (bleached pigment) back to 11-cis retinal. Retinal organoids, however, either do not have RPE layer or carry patches of RPE mostly on one side, thus directly exposing most photoreceptors in the developing organoids to neural medium. Recreation of the critical retinal niche between the apical RPE and photoreceptors, where many retinal disease mechanisms originate, is so far unattainable, imposes clear limitations on both modeling/drug screening and transplantation approaches and is a focus of investigation in many labs. Here we dissect different retinal degenerative diseases and analyze how and where retinal organoid technology can contribute the most to developing therapies even with a current limitation and absence of long and functional outer segments, supported by RPE.
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7
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Paraoan L, Sharif U, Carlsson E, Supharattanasitthi W, Mahmud NM, Kamalden TA, Hiscott P, Jackson M, Grierson I. Secretory proteostasis of the retinal pigmented epithelium: Impairment links to age-related macular degeneration. Prog Retin Eye Res 2020; 79:100859. [PMID: 32278708 DOI: 10.1016/j.preteyeres.2020.100859] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/19/2022]
Abstract
Secretory proteostasis integrates protein synthesis, processing, folding and trafficking pathways that are essential for efficient cellular secretion. For the retinal pigment epithelium (RPE), secretory proteostasis is of vital importance for the maintenance of the structural and functional integrity of apical (photoreceptors) and basal (Bruch's membrane/choroidal blood supply) sides of the environment it resides in. This integrity is achieved through functions governed by RPE secreted proteins, which include extracellular matrix modelling/remodelling, angiogenesis and immune response modulation. Impaired RPE secretory proteostasis affects not only the extracellular environment, but leads to intracellular protein aggregation and ER-stress with subsequent cell death. Ample recent evidence implicates dysregulated proteostasis as a key factor in the development of age-related macular degeneration (AMD), the leading cause of blindness in the developed world, and research aiming to characterise the roles of various proteins implicated in AMD-associated dysregulated proteostasis unveiled unexpected facets of the mechanisms involved in degenerative pathogenesis. This review analyses cellular processes unveiled by the study of the top 200 transcripts most abundantly expressed by the RPE/choroid in the light of the specialised secretory nature of the RPE. Functional roles of these proteins and the mechanisms of their impaired secretion, due to age and genetic-related causes, are analysed in relation to AMD development. Understanding the importance of RPE secretory proteostasis in relation to maintaining retinal health and how it becomes impaired in disease is of paramount importance for the development and assessment of future therapeutic advancements involving gene and cell therapies.
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Affiliation(s)
- Luminita Paraoan
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom.
| | - Umar Sharif
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Emil Carlsson
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Wasu Supharattanasitthi
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom; Department of Physiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Nur Musfirah Mahmud
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Tengku Ain Kamalden
- Eye Research Centre, Department of Ophthalmology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Paul Hiscott
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Malcolm Jackson
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Ian Grierson
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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8
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Amini-Farsani Z, Asgharzade S. The impact of miR-183/182/96 gene regulation on the maturation, survival, and function of photoreceptor cells in the retina. J Comp Neurol 2019; 528:1616-1625. [PMID: 31785157 DOI: 10.1002/cne.24833] [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: 04/27/2019] [Revised: 11/27/2019] [Accepted: 11/27/2019] [Indexed: 12/31/2022]
Abstract
MicroRNAs (MiRNAs) play important roles in posttranscriptional processes to regulate gene expression. MiRNAs control various biological processes, such as growth, development, and differentiation. The continuous physiological function of photoreceptors and retinal pigment epithelium requires precise regulation to maintain their homeostasis and function; hence, these cells are highly susceptible to premature death in retinal degenerative disorders. MiRNAs are essential for the retinal cell maturation and function; the miR-183 cluster represents one of the most important regulatory factors for the photoreceptor cells. Various studies together with bioinformatics analyses have shown that many genes contributing to the differentiation pathway of photoreceptors are targets of the miR-183 cluster, and the miR-183 cluster dysregulation causes certain defects in the differentiation of the photoreceptors and other retinal neurons by influencing the expression of target genes. Misexpression of miR-183 cluster in the human retinal epithelial cells leads to the reprogramming and transformation of these cells to neuron- and photoreceptor-like cells, which are associated with the expression of neuron- and photoreceptor-specific markers in human retinal pigment epitheliums cells. The knockout of this cluster causes the destruction of the outer segment of the photoreceptors, which subsequently causes the cells to exhibit severe susceptibility to light and eventually degenerate. Hundreds of target genes in this family are likely to affect the development and maintenance of the retina. Identifying the genes that are regulated by the miRNA-183 cluster provides researchers with important insights into the complex development and regeneration mechanism of the retina and may offer a new way for maintaining and regenerating photoreceptor cells in neurodegenerative diseases.
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Affiliation(s)
- Zeinab Amini-Farsani
- Young Researchers and Elites Club, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Samira Asgharzade
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
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9
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Buskin A, Zhu L, Chichagova V, Basu B, Mozaffari-Jovin S, Dolan D, Droop A, Collin J, Bronstein R, Mehrotra S, Farkas M, Hilgen G, White K, Pan KT, Treumann A, Hallam D, Bialas K, Chung G, Mellough C, Ding Y, Krasnogor N, Przyborski S, Zwolinski S, Al-Aama J, Alharthi S, Xu Y, Wheway G, Szymanska K, McKibbin M, Inglehearn CF, Elliott DJ, Lindsay S, Ali RR, Steel DH, Armstrong L, Sernagor E, Urlaub H, Pierce E, Lührmann R, Grellscheid SN, Johnson CA, Lako M. Disrupted alternative splicing for genes implicated in splicing and ciliogenesis causes PRPF31 retinitis pigmentosa. Nat Commun 2018; 9:4234. [PMID: 30315276 PMCID: PMC6185938 DOI: 10.1038/s41467-018-06448-y] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 09/03/2018] [Indexed: 12/23/2022] Open
Abstract
Mutations in pre-mRNA processing factors (PRPFs) cause autosomal-dominant retinitis pigmentosa (RP), but it is unclear why mutations in ubiquitously expressed genes cause non-syndromic retinal disease. Here, we generate transcriptome profiles from RP11 (PRPF31-mutated) patient-derived retinal organoids and retinal pigment epithelium (RPE), as well as Prpf31+/- mouse tissues, which revealed that disrupted alternative splicing occurred for specific splicing programmes. Mis-splicing of genes encoding pre-mRNA splicing proteins was limited to patient-specific retinal cells and Prpf31+/- mouse retinae and RPE. Mis-splicing of genes implicated in ciliogenesis and cellular adhesion was associated with severe RPE defects that include disrupted apical - basal polarity, reduced trans-epithelial resistance and phagocytic capacity, and decreased cilia length and incidence. Disrupted cilia morphology also occurred in patient-derived photoreceptors, associated with progressive degeneration and cellular stress. In situ gene editing of a pathogenic mutation rescued protein expression and key cellular phenotypes in RPE and photoreceptors, providing proof of concept for future therapeutic strategies.
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Affiliation(s)
- Adriana Buskin
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Lili Zhu
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Valeria Chichagova
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Basudha Basu
- Leeds Institute of Medical Research, University of Leeds, St James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK
| | - Sina Mozaffari-Jovin
- Department of Cellular Biochemistry, Max-Planck-Institute of Biophysical Chemistry, Am Fassberg 11, Goettingen, D-37077, Germany
| | - David Dolan
- Department of Biological Sciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Alastair Droop
- MRC Medical Bioinformatics Centre, University of Leeds, Clarendon Way, Leeds, LS2 9JT, UK
| | - Joseph Collin
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Revital Bronstein
- Ocular Genomics Institute, Mass Eye and Ear and Harvard Medical School, 243 Charles Street, Boston, MA, 02114, USA
| | - Sudeep Mehrotra
- Ocular Genomics Institute, Mass Eye and Ear and Harvard Medical School, 243 Charles Street, Boston, MA, 02114, USA
| | - Michael Farkas
- Departments of Ophthalmology and Biochemistry, Jacobs School of Medicine and Biomedical Science, State University of New York at Buffalo, 955 Main Street, Buffalo, NY, 14203-1121, USA
| | - Gerrit Hilgen
- Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Kathryn White
- Electron Microscopy Research Services, Medical School, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Kuan-Ting Pan
- Department of Cellular Biochemistry, Max-Planck-Institute of Biophysical Chemistry, Am Fassberg 11, Goettingen, D-37077, Germany
| | - Achim Treumann
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Katarzyna Bialas
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Git Chung
- Newcastle University Protein and Proteome Analysis (NUPPA), Devonshire Building, Devonshire Terrace, Newcastle upon Tyne, NE1 7RU, UK
| | - Carla Mellough
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Yuchun Ding
- Interdisciplinary Computing and Complex Biosystems (ICOS) Research Group, School of Computing, Newcastle University, Urban Sciences Building, 1 Science Square, Newcastle Helix, Newcastle upon Tyne, NE4 5TG, UK
| | - Natalio Krasnogor
- Interdisciplinary Computing and Complex Biosystems (ICOS) Research Group, School of Computing, Newcastle University, Urban Sciences Building, 1 Science Square, Newcastle Helix, Newcastle upon Tyne, NE4 5TG, UK
| | - Stefan Przyborski
- Department of Biological Sciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Simon Zwolinski
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Jumana Al-Aama
- Princess Al Jawhara Al-Brahim Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, 7393 Al-Malae'b St, Jeddah, 22252, Saudi Arabia
| | - Sameer Alharthi
- Princess Al Jawhara Al-Brahim Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, 7393 Al-Malae'b St, Jeddah, 22252, Saudi Arabia
| | - Yaobo Xu
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Gabrielle Wheway
- Centre for Research in Biosciences, University of the West of England, Frenchay Campus, Coldharbour Lane, Bristol, BS16 1QY, UK
| | - Katarzyna Szymanska
- Leeds Institute of Medical Research, University of Leeds, St James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK
| | - Martin McKibbin
- Leeds Institute of Medical Research, University of Leeds, St James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK
| | - Chris F Inglehearn
- Leeds Institute of Medical Research, University of Leeds, St James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK
| | - David J Elliott
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Robin R Ali
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - David H Steel
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Lyle Armstrong
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Evelyne Sernagor
- Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen, D-37077, Germany
| | - Eric Pierce
- Ocular Genomics Institute, Mass Eye and Ear and Harvard Medical School, 243 Charles Street, Boston, MA, 02114, USA
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max-Planck-Institute of Biophysical Chemistry, Am Fassberg 11, Goettingen, D-37077, Germany
| | - Sushma-Nagaraja Grellscheid
- Department of Biological Sciences, Durham University, South Road, Durham, DH1 3LE, UK.
- Computational Biology Unit, Department of Biological Sciences, University of Bergen, Thormohlensgt 55, Bergen, N-5008, Norway.
| | - Colin A Johnson
- Leeds Institute of Medical Research, University of Leeds, St James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK.
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK.
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10
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Negative regulators of angiogenesis: important targets for treatment of exudative AMD. Clin Sci (Lond) 2017; 131:1763-1780. [PMID: 28679845 DOI: 10.1042/cs20170066] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/17/2017] [Accepted: 04/03/2017] [Indexed: 12/12/2022]
Abstract
Angiogenesis contributes to the pathogenesis of many diseases including exudative age-related macular degeneration (AMD). It is normally kept in check by a tightly balanced production of pro- and anti-angiogenic factors. The up-regulation of the pro-angiogenic factor, vascular endothelial growth factor (VEGF), is intimately linked to the pathogenesis of exudative AMD, and its antagonism has been effectively targeted for treatment. However, very little is known about potential changes in expression of anti-angiogenic factors and the role they play in choroidal vascular homeostasis and neovascularization associated with AMD. Here, we will discuss the important role of thrombospondins and pigment epithelium-derived factor, two major endogenous inhibitors of angiogenesis, in retinal and choroidal vascular homeostasis and their potential alterations during AMD and choroidal neovascularization (CNV). We will review the cell autonomous function of these proteins in retinal and choroidal vascular cells. We will also discuss the potential targeting of these molecules and use of their mimetic peptides for therapeutic development for exudative AMD.
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11
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Photoreceptor Outer Segment-like Structures in Long-Term 3D Retinas from Human Pluripotent Stem Cells. Sci Rep 2017; 7:766. [PMID: 28396597 PMCID: PMC5429674 DOI: 10.1038/s41598-017-00774-9] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 03/14/2017] [Indexed: 12/22/2022] Open
Abstract
The retinal degenerative diseases, which together constitute a leading cause of hereditary blindness worldwide, are largely untreatable. Development of reliable methods to culture complex retinal tissues from human pluripotent stem cells (hPSCs) could offer a means to study human retinal development, provide a platform to investigate the mechanisms of retinal degeneration and screen for neuroprotective compounds, and provide the basis for cell-based therapeutic strategies. In this study, we describe an in vitro method by which hPSCs can be differentiated into 3D retinas with at least some important features reminiscent of a mature retina, including exuberant outgrowth of outer segment-like structures and synaptic ribbons, photoreceptor neurotransmitter expression, and membrane conductances and synaptic vesicle release properties consistent with possible photoreceptor synaptic function. The advanced outer segment-like structures reported here support the notion that 3D retina cups could serve as a model for studying mature photoreceptor development and allow for more robust modeling of retinal degenerative disease in vitro.
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PEDF and its roles in physiological and pathological conditions: implication in diabetic and hypoxia-induced angiogenic diseases. Clin Sci (Lond) 2015; 128:805-23. [PMID: 25881671 PMCID: PMC4557399 DOI: 10.1042/cs20130463] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pigment epithelium-derived factor (PEDF) is a broadly expressed multifunctional member of the serine proteinase inhibitor (serpin) family. This widely studied protein plays critical roles in many physiological and pathophysiological processes, including neuroprotection, angiogenesis, fibrogenesis and inflammation. The present review summarizes the temporal and spatial distribution patterns of PEDF in a variety of developing and adult organs, and discusses its functions in maintaining physiological homoeostasis. The major focus of the present review is to discuss the implication of PEDF in diabetic and hypoxia-induced angiogenesis, and the pathways mediating PEDF's effects under these conditions. Furthermore, the regulatory mechanisms of PEDF expression, function and degradation are also reviewed. Finally, the therapeutic potential of PEDF as an anti-angiogenic drug is briefly summarized.
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Thangaraj G, Christophel J, Bachmann G, Greif A, Layer PG. PEDF counteracts DL-α-aminoadipate toxicity and rescues gliotoxic damages in RPE-free chicken retinal explants. Exp Eye Res 2015; 134:111-22. [PMID: 25686916 DOI: 10.1016/j.exer.2015.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/21/2015] [Accepted: 02/12/2015] [Indexed: 01/03/2023]
Abstract
Gliotoxic responses complicate human eye diseases, the causes of which often remain obscure. Here, we activated Müller cells (MCs) by the gliotoxin DL-α-aminoadipate (AAA) and assayed possible protective effects by pigment epithelium-derived factor (PEDF) in RPE-free retinal explants of the E6 chick embryo. These models are suited to analyze gliotoxic reactions in vitro, since the avian retina contains only Müller cells (MCs) as glial components, and the RPE-free explants are devoid of a major PEDF source. ChAT- and AChE-immunohistochemistry (IHC) revealed that AAA treatment disrupted the differentiation of cholinergic amacrine cells in the inner plexiform layer. At the applied concentration of 1 mM AAA, apoptosis of MCs was slightly increased, as shown by TUNEL and caspase-3 activity assays. Concomitantly, cell-free gaps emerged in the middle of the retina, where MCs were swollen and amassed glutamine synthetase (shown by GS and Vimentin IHC). AAA treatment strongly activated MCs, as shown by GFAP IHC, and by an increase of stress-related catalase activity. Remarkably, nearly all effects of AAA on MCs were effectively counter-balanced by 50 ng/ml PEDF co-treatment, as also shown by RT-PCR. These findings suggest that supplementation with PEDF can protect the retina against gliotoxic attacks. Further studies should establish whether PEDF similarly protects a gliotoxic human retina.
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Affiliation(s)
- Gopenath Thangaraj
- Technische Universität Darmstadt, Entwicklungsbiologie und Neurogenetik, Schnittspahnstrasse 13, D-64287 Darmstadt, Germany
| | - Jeanette Christophel
- Technische Universität Darmstadt, Entwicklungsbiologie und Neurogenetik, Schnittspahnstrasse 13, D-64287 Darmstadt, Germany
| | - Gesine Bachmann
- Technische Universität Darmstadt, Entwicklungsbiologie und Neurogenetik, Schnittspahnstrasse 13, D-64287 Darmstadt, Germany
| | - Alexander Greif
- Technische Universität Darmstadt, Entwicklungsbiologie und Neurogenetik, Schnittspahnstrasse 13, D-64287 Darmstadt, Germany
| | - Paul G Layer
- Technische Universität Darmstadt, Entwicklungsbiologie und Neurogenetik, Schnittspahnstrasse 13, D-64287 Darmstadt, Germany.
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Li F, Song N, Tombran-Tink J, Niyibizi C. Pigment epithelium-derived factor enhances differentiation and mineral deposition of human mesenchymal stem cells. Stem Cells 2015; 31:2714-23. [PMID: 23939834 DOI: 10.1002/stem.1505] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/12/2013] [Accepted: 07/22/2013] [Indexed: 12/17/2022]
Abstract
Pigment epithelium-derived factor (PEDF) is a potent antiangiogenic factor found in a wide variety of tissues. Recent findings indicated that lack of PEDF leads to osteogenesis imperfecta type VI whose hallmark is a defect in mineralization. We investigated the effects of PEDF on human mesenchymal stem cells (hMSCs) and signaling pathways through which PEDF displays its activities in hMSCs. hMSCs incubated in a medium supplemented with PEDF induced expression of osteoblastic-related genes. In addition, PEDF induced alkaline phosphatase (ALP) activity in MSCs at 14 days of incubation in maintenance medium; hMSCs incubated in osteogenic medium in presence of PEDF expressed 19% more ALP activity (35.655 ± 1.827 U/mg protein, p = .041 than cells incubated in the same medium without PEDF supplementation (29.956 ± 2.100 U/μg protein). hMSCs incubated in osteogenic medium in presence of PEDF deposited 50% more mineral (2.108 ± 0.306 OD/ml per well per 1 × 10(4) cells per square centimeter, p = .017) than MSCs incubated in absence of the protein (1.398 ± 0.098 OD/ml per well per 1 × 10(4) cells per square centimeter) as determined by Alizarin Red quantitation. Reduction in PEDF expression in MSCs by siRNA led to decreased ALP activity (33.552 ± 2.009 U/ng protein of knockdown group vs. 39.269 ± 3.533 U/ng protein of scrambled siRNA group, p = .039) and significant reduction in mineral deposition (0.654 ± 0.050 OD/ml per well per 1 × 10(4) cells per square centimeter of knockdown group vs. 1.152 ± 0.132 OD/ml per well per 1 × 10(4) cells per square centimeter of wild-type group, p = .010). Decreased ALP activity and mineral deposition were restored by supplementation with exogenous PEDF protein. PEDF activated ERK and AKT signaling pathways in MSCs to induce expression of osteoblastic-related genes. These data suggest that PEDF is involved in MSCs osteoblastic differentiation.
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Affiliation(s)
- Feng Li
- Department of Orthopaedics and Rehabilitation, Division of Musculoskeletal Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
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Lv B, Wang R, Gao X, Dong X, Ji X. Effect of vascular endothelial growth factor on retinal ganglion cells of rats with chronic intraocular hypertension. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:5717-5724. [PMID: 25337213 PMCID: PMC4203184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/23/2014] [Indexed: 06/04/2023]
Abstract
AIM To investigate the effect of vascular endothelial growth factor (VEGF) on the expression of pigment epithelium-derived factor (PEDF) in retina and the protective effect of VEGF on retinal ganglion cells (RGCs) of rats with chronic elevated intraocular pressure (EIOP) and it's potential mechanism. METHODS 30 females Sprague-Dawley rats were randomly divided into three groups: EIOP + VEGF group (A), EIOP + vehicle group (B) and sham operated + VEGF group (C). The EIOP was introduced by obstructing episcleral veins in Group A and Group B. In the Group C, only the bulber conjunctiva was opened without obstructing episcleral veins. Immediately after surgery, rats in the Group A and Group C were intravitreously injected with 2 μL of VEGF. In the Group B, rats were intravitreously treated with 2 μL of normal saline. At 3 and 14 days after injection, animals were sacrificed and the eyes were collected for preparation of frozen sections. RESULTS After surgery, the IOP increased significantly in the Group A and Group B. There was no significant difference in the IOP at day 3 and day 14 after operation. The PEDF expression in the Group A and Group B was higher than that in the Group C. TUNEL staining showed the apoptotic RGCs markedly reduced after VEGF treatment when compared with rats without treatment. CONCLUSION Intravitreal treatment with VEGF may reduce the apoptosis of RGCs in rats with chronic intraocular hypertension.
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Affiliation(s)
- Bingjian Lv
- 474 Hospital of PLA Xinjiang Uygur Autonomous Region, Urumqi 830013, China
| | - Ruifu Wang
- 474 Hospital of PLA Xinjiang Uygur Autonomous Region, Urumqi 830013, China
| | - Xiaowei Gao
- 474 Hospital of PLA Xinjiang Uygur Autonomous Region, Urumqi 830013, China
| | - Xiaoyun Dong
- 474 Hospital of PLA Xinjiang Uygur Autonomous Region, Urumqi 830013, China
| | - Xiuxiang Ji
- 474 Hospital of PLA Xinjiang Uygur Autonomous Region, Urumqi 830013, China
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Pinzon-Guzman C, Xing T, Zhang SSM, Barnstable CJ. Regulation of rod photoreceptor differentiation by STAT3 is controlled by a tyrosine phosphatase. J Mol Neurosci 2014; 55:152-159. [PMID: 25108518 DOI: 10.1007/s12031-014-0397-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/30/2014] [Indexed: 11/25/2022]
Abstract
Signal pathways that reduce the levels of tyrosine-phosphorylated STAT3 (pSTAT3) allow late retinal progenitors to exit the cell cycle and enter a terminal differentiation pathway into rod photoreceptors. In the mouse retina, we previously identified PKC-β1 and PKC-γ isoforms as essential components of a key signal pathway and IGF-1 as a major extrinsic factor regulating rod formation. In this manuscript, we demonstrate that PKC decreases phosphotyrosine but not phosphoserine on STAT3 in neonatal mouse retinas. Neither IGF-1 nor PMA induced a significant change in the levels of STAT3 or in the levels of the key proteins regulating STAT3 degradation, SOCS3, and PIAS3. Treatment of neonatal mouse retinal explants with sodium orthovanadate inhibited the PKC-mediated reduction in pSTAT3, indicating a role for a phosphatase. Addition of the PTEN inhibitor bpV(phen) to explant cultures treated with IGF-1 or PMA had no effect on the reduction in pSTAT3 levels, but the effect of both IGF-1 and PMA was blocked by a concentration of the inhibitor NSC87877 that is selective for the phosphatases Shp1 and Shp2. Inhibition of Shp1/2 phosphatases was also sufficient to abolish the IGF1-mediated induction of rod photoreceptor differentiation in the retina explant cultures. We conclude that one or both of these phosphatases are key components regulating the formation of rod photoreceptors in mouse retina.
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Affiliation(s)
- Carolina Pinzon-Guzman
- Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, PA, 17033-2255, USA
| | - Tiaosi Xing
- Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, PA, 17033-2255, USA
| | - Samuel Shao-Min Zhang
- Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, PA, 17033-2255, USA
| | - Colin J Barnstable
- Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, PA, 17033-2255, USA.
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Layer PG, Araki M, Vogel-Höpker A. New concepts for reconstruction of retinal and pigment epithelial tissues. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.10.42] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Zhang L, Ma P, Collery R, Trowbridge S, Zhang M, Zhong W, Leung YF. Expression profiling of the RPE in zebrafish smarca4 mutant revealed altered signals that potentially affect RPE and retinal differentiation. Mol Vis 2014; 20:56-72. [PMID: 24426776 PMCID: PMC3888495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 01/02/2014] [Indexed: 10/26/2022] Open
Abstract
PURPOSE The purpose of this study was to develop a framework for analyzing retinal pigment epithelium (RPE) expression profiles from zebrafish eye mutants. METHODS The fish model we used was SWI/SNF-related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 4 (smarca4), a retinal dystrophic mutant with a previously described retinal phenotype and expression profiles. Histological and Affymetrix GeneChip analyses were conducted to characterize the RPE defects and underlying differential expression, respectively. RESULTS Histological analysis revealed that smarca4 RPE was formed, but its differentiation was abnormal. In particular, ultrastructural analysis of smarca4 RPE by transmission electron microscopy demonstrated several defects in melanogenesis. The nature of these defects also suggests that the cytoskeletal dynamics, which are tightly linked with melanogenesis, were impaired in smarca4 RPE. To compare the expression profile of normal wild-type (WT) and smarca4 RPE, the gene expression profiles of microdissected retinas and RPE-attached retinas were measured with Affymetrix GeneChip analysis. The RPE expression values were then estimated from these samples by subtracting the retinal expression values from the expression values of the RPE-attached retinas. A factorial analysis was conducted using the expression values of the RPE, retinal, and whole-embryo samples. Specific rules (contrasts) were built using the coefficients of the resulting fitted models to select for three groups of genes: 1) smarca4-regulated RPE genes, 2) smarca4-regulated retinal genes, and 3) smarca4-regulated RPE genes that are not differentially expressed in the retina. Interestingly, the third group consists of 39 genes that are highly related to cytoskeletal dynamics, melanogenesis, and paracrine and intracellular signal transduction. CONCLUSIONS Our analytical framework provides an experimental approach to identify differentially-regulated genes in the retina and the RPE of zebrafish mutants in which both of these tissues are affected by the underlying mutation. Specifically, we have used the method to identify a group of 39 genes that can potentially explain the melanogenesis defect in the smarca4 RPE. In addition, several genes in this group are secreted signaling molecules. Thus, this observation further implicates that the smarca4 RPE might play a role in the retinal dystrophic phenotype in smarca4.
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Affiliation(s)
- Liyun Zhang
- Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Ping Ma
- Department of Statistics, University of Georgia, Athens, GA
| | - Ross Collery
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI
| | - Sara Trowbridge
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA
| | - Mingzhi Zhang
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Wenxuan Zhong
- Department of Statistics, University of Georgia, Athens, GA
| | - Yuk Fai Leung
- Department of Biological Sciences, Purdue University, West Lafayette, IN,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine Lafayette, West Lafayette, IN
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Semple-Rowland S, Madorsky I, Bolch S, Berry J, Smith WC. Activation of phospholipase C mimics the phase shifting effects of light on melatonin rhythms in retinal photoreceptors. PLoS One 2013; 8:e83378. [PMID: 24386190 PMCID: PMC3873303 DOI: 10.1371/journal.pone.0083378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/02/2013] [Indexed: 12/04/2022] Open
Abstract
Many aspects of retinal photoreceptor function and physiology are regulated by the circadian clocks in these cells. It is well established that light is the primary stimulus that entrains these clocks; yet, the biochemical cascade(s) mediating light’s effects on these clocks remains unknown. This deficiency represents a significant gap in our fundamental understanding of photoreceptor signaling cascades and their functions. In this study, we utilized re-aggregated spheroid cultures prepared from embryonic chick retina to determine if activation of phospholipase C in photoreceptors in the absence of light can phase shift the melatonin secretion rhythms of these cells in a manner similar to that induced by light. We show that spheroid cultures rhythmically secrete melatonin and that these melatonin rhythms can be dynamically phase shifted by exposing the cultures to an appropriately timed light pulse. Importantly, we show that activation of phospholipase C using m-3M3FBS in the absence of light induces a phase delay in photoreceptor melatonin rhythms that mirrors that induced by light. The implication of this finding is that the light signaling cascade that entrains photoreceptor melatonin rhythms involves activation of phospholipase C.
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Affiliation(s)
- Susan Semple-Rowland
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
| | - Irina Madorsky
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
| | - Susan Bolch
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States of America
| | - Jonathan Berry
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
| | - W. Clay Smith
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States of America
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Calenda G, Strong TD, Pavlovich CP, Schaeffer EM, Burnett AL, Yu W, Davies KP, Bivalacqua TJ. Whole genome microarray of the major pelvic ganglion after cavernous nerve injury: new insights into molecular profile changes after nerve injury. BJU Int 2012; 109:1552-64. [DOI: 10.1111/j.1464-410x.2011.10705.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Gvritishvili AG, Leung KW, Tombran-Tink J. Codon preference optimization increases heterologous PEDF expression. PLoS One 2010; 5:e15056. [PMID: 21152082 PMCID: PMC2994832 DOI: 10.1371/journal.pone.0015056] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Accepted: 10/04/2010] [Indexed: 12/26/2022] Open
Abstract
Pigment epithelium-derived factor (PEDF) is widely known for its neurotrophic and antiangiogenic functions. Efficacy studies of PEDF in animal models are limited because of poor heterologous protein yields. Here, we redesigned the human PEDF gene to preferentially match codon frequencies of E coli without altering the amino acid sequence. Following de novo synthesis, codon optimized PEDF (coPEDF) and the wtPEDF genes were cloned into pET32a containing a 5′ thioredoxin sequence (Trx) and the recombinant Trx-coPEDF or Trx-wtPEDF fusion constructs expressed in native and two tRNA augmented E coli hosts - BL21-CodonPlus(DE3)-RIL and BL21-CodonPlus(DE3)-RP, carrying extra copies of tRNAarg,ile,leu and tRNAarg,pro genes , respectively. Trx-PEDF fusion proteins were isolated using Ni-NTA metal affinity chromatography and PEDF purified after cleavage with factor Xα. Protein purity and identity were confirmed by western blot, MALDI-TOF, and UV/CD spectral analyses. Expression of the synthetic gene was ∼3.4 fold greater (212.7 mg/g; 62.1 mg/g wet cells) and purified yields ∼4 fold greater (41.1 mg/g; 11.3 mg/g wet cell) than wtPEDF in the native host. A small increase in expression of both genes was observed in hosts supplemented with rare tRNA genes compared to the native host but expression of coPEDF was ∼3 fold greater than wtPEDF in both native and codon-bias-adjusted E coli strains. ΔGs at −3 to +50 of the Trx site of both fusion genes were −3.9 kcal/mol. Functionally, coPEDF was equally as effective as wtPEDF in reducing oxidative stress, promoting neurite outgrowth, and blocking endothelial tube formation. These findings suggest that while rare tRNA augmentation and mRNA folding energies can significantly contribute to increased protein expression, preferred codon usage, in this case, is advantageous to translational efficiency of biologically active PEDF in E coli. This strategy will undoubtedly fast forward studies to validate therapeutic utility of PEDF in vivo.
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Affiliation(s)
- Anzor G. Gvritishvili
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Kar Wah Leung
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Joyce Tombran-Tink
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
- Department of Ophthalmology, Penn State University College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail:
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