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Cvekl A, Vijg J. Aging of the eye: Lessons from cataracts and age-related macular degeneration. Ageing Res Rev 2024; 99:102407. [PMID: 38977082 DOI: 10.1016/j.arr.2024.102407] [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: 03/11/2024] [Revised: 06/18/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024]
Abstract
Aging is the greatest risk factor for chronic human diseases, including many eye diseases. Geroscience aims to understand the effects of the aging process on these diseases, including the genetic, molecular, and cellular mechanisms that underlie the increased risk of disease over the lifetime. Understanding of the aging eye increases general knowledge of the cellular physiology impacted by aging processes at various biological extremes. Two major diseases, age-related cataract and age-related macular degeneration (AMD) are caused by dysfunction of the lens and retina, respectively. Lens transparency and light refraction are mediated by lens fiber cells lacking nuclei and other organelles, which provides a unique opportunity to study a single aging hallmark, i.e., loss of proteostasis, within an environment of limited metabolism. In AMD, local dysfunction of the photoreceptors/retinal pigmented epithelium/Bruch's membrane/choriocapillaris complex in the macula leads to the loss of photoreceptors and eventually loss of central vision, and is driven by nearly all the hallmarks of aging and shares features with Alzheimer's disease, Parkinson's disease, cardiovascular disease, and diabetes. The aging eye can function as a model for studying basic mechanisms of aging and, vice versa, well-defined hallmarks of aging can be used as tools to understand age-related eye disease.
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Affiliation(s)
- Ales Cvekl
- Departments of Genetics and Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Jan Vijg
- Departments of Genetics and Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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2
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Liu Y, Ng L, Liu H, Heuer H, Forrest D. Cone photoreceptor differentiation regulated by thyroid hormone transporter MCT8 in the retinal pigment epithelium. Proc Natl Acad Sci U S A 2024; 121:e2402560121. [PMID: 39018199 PMCID: PMC11287251 DOI: 10.1073/pnas.2402560121] [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: 02/06/2024] [Accepted: 06/17/2024] [Indexed: 07/19/2024] Open
Abstract
The key role of a thyroid hormone receptor in determining the maturation and diversity of cone photoreceptors reflects a profound influence of endocrine signaling on the cells that mediate color vision. However, the route by which hormone reaches cones remains enigmatic as cones reside in the retinal photoreceptor layer, shielded by the blood-retina barrier. Using genetic approaches, we report that cone differentiation is regulated by a membrane transporter for thyroid hormone, MCT8 (SLC16A2), in the retinal pigment epithelium (RPE), which forms the outer blood-retina barrier. Mct8-deficient mice display hypothyroid-like cone gene expression and compromised electroretinogram responses. Mammalian color vision is typically facilitated by cone types that detect medium-long (M) and short (S) wavelengths of light but Mct8-deficient mice have a partial shift of M to S cone identity, resembling the phenotype of thyroid hormone receptor deficiency. RPE-specific ablation of Mct8 results in similar shifts in cone identity and hypothyroid-like gene expression whereas reexpression of MCT8 in the RPE in Mct8-deficient mice partly restores M cone identity, consistent with paracrine-like control of thyroid hormone signaling by the RPE. Our findings suggest that in addition to transport of essential solutes and homeostatic support for photoreceptors, the RPE regulates the thyroid hormone signal that promotes cone-mediated vision.
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Affiliation(s)
- Ye Liu
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD20892
| | - Lily Ng
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD20892
| | - Hong Liu
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD20892
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Essen, University Duisburg-Essen, Essen45147, Germany
| | - Douglas Forrest
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD20892
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3
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Nakai-Futatsugi Y, Jin J, Ogawa T, Sakai N, Maeda A, Hironaka KI, Fukuda M, Danno H, Tanaka Y, Hori S, Shiroguchi K, Takahashi M. Pigmentation level of human iPSC-derived RPE does not indicate a specific gene expression profile. eLife 2024; 12:RP92510. [PMID: 38722314 PMCID: PMC11081631 DOI: 10.7554/elife.92510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024] Open
Abstract
Retinal pigment epithelium (RPE) cells show heterogeneous levels of pigmentation when cultured in vitro. To know whether their color in appearance is correlated with the function of the RPE, we analyzed the color intensities of human-induced pluripotent stem cell-derived RPE cells (iPSC-RPE) together with the gene expression profile at the single-cell level. For this purpose, we utilized our recent invention, Automated Live imaging and cell Picking System (ALPS), which enabled photographing each cell before RNA-sequencing analysis to profile the gene expression of each cell. While our iPSC-RPE were categorized into four clusters by gene expression, the color intensity of iPSC-RPE did not project any specific gene expression profiles. We reasoned this by less correlation between the actual color and the gene expressions that directly define the level of pigmentation, from which we hypothesized the color of RPE cells may be a temporal condition not strongly indicating the functional characteristics of the RPE.
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Affiliation(s)
- Yoko Nakai-Futatsugi
- Laboratory for Retinal Regeneration, RIKEN Biosystems Dynamics Research (BDR)KobeJapan
- VC Cell Therapy IncKobeJapan
- Ritsumeikan UniversityShigaJapan
| | - Jianshi Jin
- Laboratory for Prediction of Cell Systems Dynamics, RIKEN Center for Biosystems Dynamics Research (BDR)SuitaJapan
| | - Taisaku Ogawa
- Laboratory for Prediction of Cell Systems Dynamics, RIKEN Center for Biosystems Dynamics Research (BDR)SuitaJapan
| | - Noriko Sakai
- Laboratory for Retinal Regeneration, RIKEN Biosystems Dynamics Research (BDR)KobeJapan
- VC Cell Therapy IncKobeJapan
| | - Akiko Maeda
- Laboratory for Retinal Regeneration, RIKEN Biosystems Dynamics Research (BDR)KobeJapan
- Ritsumeikan UniversityShigaJapan
- Kobe City Eye Hospital, Department of OphthalmologyKobeJapan
| | | | | | | | - Yuji Tanaka
- Laboratory for Retinal Regeneration, RIKEN Biosystems Dynamics Research (BDR)KobeJapan
| | | | - Katsuyuki Shiroguchi
- Laboratory for Prediction of Cell Systems Dynamics, RIKEN Center for Biosystems Dynamics Research (BDR)SuitaJapan
| | - Masayo Takahashi
- Laboratory for Retinal Regeneration, RIKEN Biosystems Dynamics Research (BDR)KobeJapan
- Ritsumeikan UniversityShigaJapan
- Kobe City Eye Hospital, Department of OphthalmologyKobeJapan
- Vision Care, IncKobeJapan
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Faura G, Studenovska H, Sekac D, Ellederova Z, Petrovski G, Eide L. The Effects of the Coating and Aging of Biodegradable Polylactic Acid Membranes on In Vitro Primary Human Retinal Pigment Epithelium Cells. Biomedicines 2024; 12:966. [PMID: 38790928 PMCID: PMC11117638 DOI: 10.3390/biomedicines12050966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 05/26/2024] Open
Abstract
Age-related macular degeneration (AMD) is the most frequent cause of blindness in developed countries. The replacement of dysfunctional human retinal pigment epithelium (hRPE) cells by the transplantation of in vitro-cultivated hRPE cells to the affected area emerges as a feasible strategy for regenerative therapy. Synthetic biomimetic membranes arise as powerful hRPE cell carriers, but as biodegradability is a requirement, it also poses a challenge due to its limited durability. hRPE cells exhibit several characteristics that putatively respond to the type of membrane carrier, and they can be used as biomarkers to evaluate and further optimize such membranes. Here, we analyze the pigmentation, transepithelial resistance, genome integrity, and maturation markers of hRPE cells plated on commercial polycarbonate (PC) versus in-house electrospun polylactide-based (PLA) membranes, both enabling separate apical/basolateral compartments. Our results show that PLA is superior to PC-based membranes for the cultivation of hRPEs, and the BEST1/RPE65 maturation markers emerge as the best biomarkers for addressing the quality of hRPE cultivated in vitro. The stability of the cultures was observed to be affected by PLA aging, which is an effect that could be partially palliated by the coating of the PLA membranes.
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Affiliation(s)
- Georgina Faura
- Department of Medical Biochemistry, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0372 Oslo, Norway
- CIDETEC, Basque Research and Technology Alliance (BRTA), 20014 Donostia-San Sebastián, Spain
| | - Hana Studenovska
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 00 Prague, Czech Republic;
| | - David Sekac
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 277 21 Libechov, Czech Republic; (D.S.); (Z.E.)
- Department of Cell Biology, Faculty of Science, Charles University, 128 00 Prague, Czech Republic
| | - Zdenka Ellederova
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 277 21 Libechov, Czech Republic; (D.S.); (Z.E.)
| | - Goran Petrovski
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Oslo University Hospital and Institute for Clinical Medicine, University of Oslo, 0424 Oslo, Norway;
- Norwegian Center for Stem Cell Research, Oslo University Hospital, 0424 Oslo, Norway
- Department of Ophthalmology, University Hospital Centre, University of Split School of Medicine, 21000 Split, Croatia
- UKLO Network, University St. Kliment Ohridski, 7000 Bitola, North Macedonia
| | - Lars Eide
- Department of Medical Biochemistry, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0372 Oslo, Norway
- Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway
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Nam U, Lee S, Jeon JS. Generation of a 3D Outer Blood-Retinal Barrier with Advanced Choriocapillaris and Its Application in Diabetic Retinopathy in a Microphysiological System. ACS Biomater Sci Eng 2023; 9:4929-4939. [PMID: 37494673 DOI: 10.1021/acsbiomaterials.3c00326] [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] [Indexed: 07/28/2023]
Abstract
The outer blood-retinal barrier (oBRB) provides an optimal environment for the function of the photoreceptor by regulating the exchange of molecules between subretinal space and the choriocapillaris, and its dysfunction could impair the photoreceptor's function and vision. The existing in vitro models have limitations in reproducing the barrier function or physiological characteristics of oBRB and choriocapillaris. Here, we engineered a microphysiological system-based oBRB-choriocapillaris model that simultaneously incorporates the desired physiological characteristics and is simple to fabricate. First, we generated microvascular networks to mimic choriocapillaris and investigated the role of fibroblasts in vasculogenesis. By adding retinal pigment epithelial cells to one side of blood vessels formed with endothelial cells and fibroblasts and optimizing their culture medium conditions, we established an oBRB-choriocapillaris model. To verify the physiological similarity of our oBRB-choriocapillaris model, we identified the polarization and expression of the tight junction of the retinal pigment epithelium, Bruch's membrane, and the fenestral diaphragm of choriocapillaris. Finally, we tried to recapitulate the diabetes mellitus environment in our model with hyperglycemia and diabetes-related cytokines. This induced a decrease in tight junction integrity, loss of barrier function, and shrinkage of blood vessels, similar to the in vivo pathological changes observed in the oBRB and choriocapillaris. The oBRB-choriocapillaris model developed using a microphysiological system is expected to offer a valuable in vitro platform for retinal and choroidal vascular diseases in preclinical applications.
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Affiliation(s)
- Ungsig Nam
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Seokhun Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Jessie S Jeon
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- KAIST Institute for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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Ahmad S, Wright KN, VonCannon JL, Ferrario CM, Ola MS, Choudhary M, Malek G, Gustafson JR, Sappington RM. Internalization of Angiotensin-(1-12) in Adult Retinal Pigment Epithelial-19 Cells. J Ocul Pharmacol Ther 2023; 39:290-299. [PMID: 36944130 PMCID: PMC10178934 DOI: 10.1089/jop.2022.0139] [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: 09/22/2022] [Accepted: 02/12/2023] [Indexed: 03/23/2023] Open
Abstract
Purpose: Angiotensin-(1-12) [Ang-(1-12)] serves as a primary substrate to generate angiotensin II (Ang II) by angiotensin-converting enzyme and/or chymase suggests it may be an unrecognized source of Ang II-mediated microvascular complication in hypertension-mediated retinopathy. We investigated Ang-(1-12) expression and internalization in adult retinal pigment epithelial-19 (ARPE-19) cultured cells. We performed the internalization of Ang-(1-12) in ARPE-19 cells in the presence of a highly specific monoclonal antibody (mAb) developed against the C-terminal end of the Ang-(1-12) sequence. Methods: All experiments were performed in confluent ARPE-19 cells (passage 28-35). We employed high-performance liquid chromatography to purify radiolabeled, 125I-Ang-(1-12) and immuno-neutralization with Ang-(1-12) mAb to demonstrate Ang-(1-12)'s internalization in ARPE-19 cells. Internalization was also demonstrated by immunofluorescence (IF) method. Results: These procedures revealed internalization of an intact 125I-Ang-(1-12) in ARPE-19 cells. A significant reduction (∼53%, P < 0.0001) in 125I-Ang-(1-12) internalization was detected in APRE-19 cells in the presence of the mAb. IF staining experiments further confirms internalization of Ang-(1-12) into the cells from the extracellular culture medium. No endogenous expression was detected in the ARPE-19 cells. An increased intensity of IF staining was detected in cells exposed to 1.0 μM Ang-(1-12) compared with 0.1 μM. Furthermore, we found hydrolysis of Ang-(1-12) into Ang II by ARPE-19 cells' plasma membranes. Conclusions: Intact Ang-(1-12) peptide is internalized from the extracellular spaces in ARPE-19 cells and metabolized into Ang II. The finding that a selective mAb blocks cellular internalization of Ang-(1-12) suggests alternate therapeutic approaches to prevent/reduce the RPE cells Ang II burden.
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Affiliation(s)
- Sarfaraz Ahmad
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Kendra N. Wright
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Jessica L. VonCannon
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Carlos M. Ferrario
- Department of Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Mohammad S. Ola
- Department of Biochemistry, King Saud University, Riyadh, Saudi Arabia
| | - Mayur Choudhary
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Goldis Malek
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Jenna R. Gustafson
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Rebecca M. Sappington
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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Eade KT, Ansell BRE, Giles S, Fallon R, Harkins-Perry S, Nagasaki T, Tzaridis S, Wallace M, Mills EA, Farashi S, Johnson A, Sauer L, Hart B, Diaz-Rubio ME, Bahlo M, Metallo C, Allikmets R, Gantner ML, Bernstein PS, Friedlander M. iPSC-derived retinal pigmented epithelial cells from patients with macular telangiectasia show decreased mitochondrial function. J Clin Invest 2023; 133:e163771. [PMID: 37115691 PMCID: PMC10145939 DOI: 10.1172/jci163771] [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: 07/21/2022] [Accepted: 03/14/2023] [Indexed: 04/29/2023] Open
Abstract
Patient-derived induced pluripotent stem cells (iPSCs) provide a powerful tool for identifying cellular and molecular mechanisms of disease. Macular telangiectasia type 2 (MacTel) is a rare, late-onset degenerative retinal disease with an extremely heterogeneous genetic architecture, lending itself to the use of iPSCs. Whole-exome sequencing screens and pedigree analyses have identified rare causative mutations that account for less than 5% of cases. Metabolomic surveys of patient populations and GWAS have linked MacTel to decreased circulating levels of serine and elevated levels of neurotoxic 1-deoxysphingolipids (1-dSLs). However, retina-specific, disease-contributing factors have yet to be identified. Here, we used iPSC-differentiated retinal pigmented epithelial (iRPE) cells derived from donors with or without MacTel to screen for novel cell-intrinsic pathological mechanisms. We show that MacTel iRPE cells mimicked the low serine levels observed in serum from patients with MacTel. Through RNA-Seq and gene set enrichment pathway analysis, we determined that MacTel iRPE cells are enriched in cellular stress pathways and dysregulation of central carbon metabolism. Using respirometry and mitochondrial stress testing, we functionally validated that MacTel iRPE cells had a reduction in mitochondrial function that was independent of defects in serine biosynthesis and 1-dSL accumulation. Thus, we identified phenotypes that may constitute alternative disease mechanisms beyond the known serine/sphingolipid pathway.
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Affiliation(s)
- Kevin T. Eade
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Brendan Robert E. Ansell
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Sarah Giles
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Regis Fallon
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Sarah Harkins-Perry
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Takayuki Nagasaki
- Department of Ophthalmology and
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Simone Tzaridis
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Martina Wallace
- Institute of Food and Health, School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Elizabeth A. Mills
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Samaneh Farashi
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Alec Johnson
- The Lowy Medical Research Institute, La Jolla, California, USA
| | - Lydia Sauer
- Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Barbara Hart
- Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - M. Elena Diaz-Rubio
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Melanie Bahlo
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Christian Metallo
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Rando Allikmets
- Department of Ophthalmology and
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Marin L. Gantner
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Paul S. Bernstein
- Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Martin Friedlander
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
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Experimental Models to Study Epithelial-Mesenchymal Transition in Proliferative Vitreoretinopathy. Int J Mol Sci 2023; 24:ijms24054509. [PMID: 36901938 PMCID: PMC10003383 DOI: 10.3390/ijms24054509] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
Proliferative vitreoretinal diseases (PVDs) encompass proliferative vitreoretinopathy (PVR), epiretinal membranes, and proliferative diabetic retinopathy. These vision-threatening diseases are characterized by the development of proliferative membranes above, within and/or below the retina following epithelial-mesenchymal transition (EMT) of the retinal pigment epithelium (RPE) and/or endothelial-mesenchymal transition of endothelial cells. As surgical peeling of PVD membranes remains the sole therapeutic option for patients, development of in vitro and in vivo models has become essential to better understand PVD pathogenesis and identify potential therapeutic targets. The in vitro models range from immortalized cell lines to human pluripotent stem-cell-derived RPE and primary cells subjected to various treatments to induce EMT and mimic PVD. In vivo PVR animal models using rabbit, mouse, rat, and swine have mainly been obtained through surgical means to mimic ocular trauma and retinal detachment, and through intravitreal injection of cells or enzymes to induce EMT and investigate cell proliferation and invasion. This review offers a comprehensive overview of the usefulness, advantages, and limitations of the current models available to investigate EMT in PVD.
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Kaarniranta K, Blasiak J, Liton P, Boulton M, Klionsky DJ, Sinha D. Autophagy in age-related macular degeneration. Autophagy 2023; 19:388-400. [PMID: 35468037 PMCID: PMC9851256 DOI: 10.1080/15548627.2022.2069437] [Citation(s) in RCA: 62] [Impact Index Per Article: 62.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/11/2022] [Accepted: 04/19/2022] [Indexed: 01/22/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of visual impairment in the aging population with limited understanding of its pathogenesis and a lack of effective treatment. The progression of AMD is initially characterized by atrophic alterations in the retinal pigment epithelium, as well as the formation of lysosomal lipofuscin and extracellular drusen deposits. Damage caused by chronic oxidative stress, protein aggregation and inflammatory processes may lead to geographic atrophy and/or choroidal neovascularization and fibrosis. The role of macroautophagy/autophagy in AMD pathology is steadily emerging. This review describes selective and secretory autophagy and their role in drusen biogenesis, senescence-associated secretory phenotype, inflammation and epithelial-mesenchymal transition in the pathogenesis of AMD.Abbreviations: Aβ: amyloid-beta; AMBRA1: autophagy and beclin 1 regulator 1; AMD: age-related macular degeneration; ATF6: activating transcription factor 6; ATG: autophagy related; BACE1: beta-secretase 1; BHLHE40: basic helix-loop-helix family member e40; BNIP3: BCL2 interacting protein 3; BNIP3L/NIX: BCL2 interacting protein 3 like; C: complement; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CARD: caspase recruitment domain; CDKN2A/p16: cyclin dependent kinase inhibitor 2A; CFB: complement factor B; DELEC1/Dec1; deleted in esophageal cancer 1; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; EMT: epithelial-mesenchymal transition; ER: endoplasmic reticulum; ERN1/IRE1: endoplasmic reticulum to nucleus signaling 1; FUNDC1: FUN14 domain containing 1; GABARAP: GABA type A receptor-associated protein; HMGB1: high mobility group box 1; IL: interleukin; KEAP1: kelch like ECH associated protein 1; LAP: LC3-associated phagocytosis; LAMP2: lysosomal associated membrane protein 2; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; NFE2L2: NFE2 like bZIP transcription factor 2; NLRP3; NLR family pyrin domain containing 3; NFKB/NFκB: nuclear factor kappa B; OPTN: optineurin; PARL: presenilin associated rhomboid like; PGAM5: PGAM family member 5, mitochondrial serine/threonine protein phosphatase; PINK1: PTEN induced kinase 1; POS: photoreceptor outer segment; PPARGC1A: PPARG coactivator 1 alpha; PRKN: parkin RBR E3 ubiquitin protein ligase; PYCARD/ASC: PYD and CARD domain containing; ROS: reactive oxygen species; RPE: retinal pigment epithelium; SA: secretory autophagy; SASP: senescence-associated secretory phenotype; SEC22B: SEC22 homolog B, vesicle trafficking protein; SNAP: synaptosome associated protein; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SQSTM1/p62: sequestosome 1; STX: syntaxin; TGFB2: transforming growth factor beta 2; TRIM16: tripartite motif containing 16; TWIST: twist family bHLH transcription factor; Ub: ubiquitin; ULK: unc-51 like autophagy activating kinase; UPR: unfolded protein response; UPS: ubiquitin-proteasome system; V-ATPase: vacuolar-type H+-translocating ATPase; VIM: vimentin.
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Affiliation(s)
- Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
| | - Janusz Blasiak
- Department of Molecular Genetics, University of Lodz, Lodz, Poland
| | - Paloma Liton
- Duke University, Department of Ophthalmology, Durham, NC, USA
| | - Michael Boulton
- University of Alabama at Birmingham, Department of Ophthalmology and Visual Sciences, Birmingham, AL, USA
| | - Daniel J. Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Debasish Sinha
- University of Pittsburgh School of Medicine, Departments of Ophthalmology, Cell Biology, and Developmental Biology, Pittsburgh, PA, USA
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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10
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Farnoodian M, Bose D, Khristov V, Susaimanickam PJ, Maddileti S, Mariappan I, Abu-Asab M, Campos M, Villasmil R, Wan Q, Maminishkis A, McGaughey D, Barone F, Gundry RL, Riordon DR, Boheler KR, Sharma R, Bharti K. Cell-autonomous lipid-handling defects in Stargardt iPSC-derived retinal pigment epithelium cells. Stem Cell Reports 2022; 17:2438-2450. [DOI: 10.1016/j.stemcr.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
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11
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Segurado A, Rodríguez-Carrillo A, Castellanos B, Hernández-Galilea E, Velasco A, Lillo C. Scribble basal polarity acquisition in RPE cells and its mislocalization in a pathological AMD-like model. Front Neuroanat 2022; 16:983151. [PMID: 36213611 PMCID: PMC9539273 DOI: 10.3389/fnana.2022.983151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/25/2022] [Indexed: 11/13/2022] Open
Abstract
Apicobasal polarity is a hallmark of retinal pigment epithelium cells and is required to perform their functions; however, the precise roles of the different proteins that execute polarity are still poorly understood. Here, we have studied the expression and location of Scribble, the core member of the polarity basal protein complex in epithelial-derived cells, in human and mouse RPE cells in both control and pathological conditions. We found that Scribble specifically localizes at the basolateral membrane of mouse and human RPE cells. In addition, we observed an increase in the expression of Scribble during human RPE development in culture, while it acquires a well-defined basolateral pattern as this process is completed. Finally, the expression and location of Scribble were analyzed in human RPE cells in experimental conditions that mimic the toxic environment suffered by these cells during AMD development and found an increase in Scribble expression in cells that develop a pathological phenotype, suggesting that the protein could be altered in cells under stress conditions, as occurs in AMD. Together, our results demonstrate, for the first time, that Scribble is expressed in both human and mouse RPE and is localized at the basolateral membrane in mature cells. Furthermore, Scribble shows impaired expression and location in RPE cells in pathological conditions, suggesting a possible role for this protein in the development of pathologies, such as AMD.
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Affiliation(s)
- Alicia Segurado
- Department of Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
- Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
- Plasticity, Degeneration, and Regeneration of the Visual System Group, Institute for Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
| | - Alba Rodríguez-Carrillo
- Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
| | - Bárbara Castellanos
- Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
| | - Emiliano Hernández-Galilea
- Plasticity, Degeneration, and Regeneration of the Visual System Group, Institute for Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
- Department of Surgery, Ophthalmology Service, University Hospital of Salamanca, University of Salamanca, Salamanca, Spain
| | - Almudena Velasco
- Department of Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
- Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
- Plasticity, Degeneration, and Regeneration of the Visual System Group, Institute for Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
| | - Concepción Lillo
- Department of Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
- Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
- Plasticity, Degeneration, and Regeneration of the Visual System Group, Institute for Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
- *Correspondence: Concepción Lillo
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12
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Bharti K, den Hollander AI, Lakkaraju A, Sinha D, Williams DS, Finnemann SC, Bowes-Rickman C, Malek G, D'Amore PA. Cell culture models to study retinal pigment epithelium-related pathogenesis in age-related macular degeneration. Exp Eye Res 2022; 222:109170. [PMID: 35835183 PMCID: PMC9444976 DOI: 10.1016/j.exer.2022.109170] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/23/2022] [Accepted: 06/29/2022] [Indexed: 11/04/2022]
Abstract
Age-related macular degeneration (AMD) is a disease that affects the macula - the central part of the retina. It is a leading cause of irreversible vision loss in the elderly. AMD onset is marked by the presence of lipid- and protein-rich extracellular deposits beneath the retinal pigment epithelium (RPE), a monolayer of polarized, pigmented epithelial cells located between the photoreceptors and the choroidal blood supply. Progression of AMD to the late nonexudative "dry" stage of AMD, also called geographic atrophy, is linked to progressive loss of areas of the RPE, photoreceptors, and underlying choriocapillaris leading to a severe decline in patients' vision. Differential susceptibility of macular RPE in AMD and the lack of an anatomical macula in most lab animal models has promoted the use of in vitro models of the RPE. In addition, the need for high throughput platforms to test potential therapies has driven the creation and characterization of in vitro model systems that recapitulate morphologic and functional abnormalities associated with human AMD. These models range from spontaneously formed cell line ARPE19, immortalized cell lines such as hTERT-RPE1, RPE-J, and D407, to primary human (fetal or adult) or animal (mouse and pig) RPE cells, and embryonic and induced pluripotent stem cell (iPSC) derived RPE. Hallmark RPE phenotypes, such as cobblestone morphology, pigmentation, and polarization, vary significantly betweendifferent models and culture conditions used in different labs, which would directly impact their usability for investigating different aspects of AMD biology. Here the AMD Disease Models task group of the Ryan Initiative for Macular Research (RIMR) provides a summary of several currently used in vitro RPE models, historical aspects of their development, RPE phenotypes that are attainable in these models, their ability to model different aspects of AMD pathophysiology, and pros/cons for their use in the RPE and AMD fields. In addition, due to the burgeoning use of iPSC derived RPE cells, the critical need for developing standards for differentiating and rigorously characterizing RPE cell appearance, morphology, and function are discussed.
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Affiliation(s)
- Kapil Bharti
- Ocular and Stem Cell Translational Research Section, National Eye Institute, NIH, Bethesda, MD, USA.
| | - Anneke I den Hollander
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands; AbbVie, Genomics Research Center, Cambridge, MA, USA.
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, USA.
| | - Debasish Sinha
- Department of Ophthalmology, Cell Biology and Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - David S Williams
- Stein Eye Institute, Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
| | - Silvia C Finnemann
- Center of Cancer, Genetic Diseases, and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY, USA.
| | - Catherine Bowes-Rickman
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA; Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA.
| | - Goldis Malek
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA; Department of Pathology, Duke University School of Medicine, Durham, NC, USA.
| | - Patricia A D'Amore
- Mass Eye and Ear, Departments of Ophthalmology and Pathology, Harvard Medical School, Boston, MA, USA.
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13
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Collin GB, Shi L, Yu M, Akturk N, Charette JR, Hyde LF, Weatherly SM, Pera MF, Naggert JK, Peachey NS, Nishina PM, Krebs MP. A Splicing Mutation in Slc4a5 Results in Retinal Detachment and Retinal Pigment Epithelium Dysfunction. Int J Mol Sci 2022; 23:2220. [PMID: 35216333 PMCID: PMC8875008 DOI: 10.3390/ijms23042220] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 12/29/2022] Open
Abstract
Fluid and solute transporters of the retinal pigment epithelium (RPE) are core components of the outer blood-retinal barrier. Characterizing these transporters and their role in retinal homeostasis may provide insights into ocular function and disease. Here, we describe RPE defects in tvrm77 mice, which exhibit hypopigmented patches in the central retina. Mapping and nucleotide sequencing of tvrm77 mice revealed a disrupted 5' splice donor sequence in Slc4a5, a sodium bicarbonate cotransporter gene. Slc4a5 expression was reduced 19.7-fold in tvrm77 RPE relative to controls, and alternative splice variants were detected. SLC4A5 was localized to the Golgi apparatus of cultured human RPE cells and in apical and basal membranes. Fundus imaging, optical coherence tomography, microscopy, and electroretinography (ERG) of tvrm77 mice revealed retinal detachment, hypopigmented patches corresponding to neovascular lesions, and retinal folds. Detachment worsened and outer nuclear layer thickness decreased with age. ERG a- and b-wave response amplitudes were initially normal but declined in older mice. The direct current ERG fast oscillation and light peak were reduced in amplitude at all ages, whereas other RPE-associated responses were unaffected. These results link a new Slc4a5 mutation to subretinal fluid accumulation and altered light-evoked RPE electrophysiological responses, suggesting that SLC4A5 functions at the outer blood-retinal barrier.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Lanying Shi
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA; (M.Y.); (N.S.P.)
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Nurten Akturk
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Jeremy R. Charette
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Sonia M. Weatherly
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Martin F. Pera
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA; (M.Y.); (N.S.P.)
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Avenue, Cleveland, OH 44195, USA
- Research Service, Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA
| | - Patsy M. Nishina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Mark P. Krebs
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
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14
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Li J, Qiu C, Wei Y, Yuan W, Liu J, Cui W, Zhou J, Qiu C, Guo L, Huang L, Ge Z, Yu L. Human Amniotic Epithelial Stem Cell-Derived Retinal Pigment Epithelium Cells Repair Retinal Degeneration. Front Cell Dev Biol 2021; 9:737242. [PMID: 34650985 PMCID: PMC8505778 DOI: 10.3389/fcell.2021.737242] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/06/2021] [Indexed: 01/05/2023] Open
Abstract
Age-related macular degeneration (AMD), featured with dysfunction and loss of retinal pigment epithelium (RPE), is lacking efficient therapeutic approaches. According to our previous studies, human amniotic epithelial stem cells (hAESCs) may serve as a potential seed cell source of RPE cells for therapy because they have no ethical concerns, no tumorigenicity, and little immunogenicity. Herein, trichostatin A and nicotinamide can direct hAESCs differentiation into RPE like cells. The differentiated cells display the morphology, marker expression and cellular function of the native RPE cells, and noticeably express little MHC class II antigens and high level of HLA-G. Moreover, visual function and retinal structure of Royal College of Surgeon (RCS) rats, a classical animal model of retinal degeneration, were rescued after subretinal transplantation with the hAESCs-derived RPE like cells. Our study possibly makes some contribution to the resource of functional RPE cells for cell therapy. Subretinal transplantation of hAESCs-RPE could be an optional therapeutic strategy for retinal degeneration diseases.
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Affiliation(s)
- Jinying Li
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China.,College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Chen Qiu
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China.,College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Yang Wei
- School of Pharmaceutical Sciences, Hangzhou Medical College, Hangzhou, China
| | - Weixin Yuan
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jia Liu
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China.,College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Wenyu Cui
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China.,College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Jiayi Zhou
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China.,College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Cong Qiu
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China.,College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Lihe Guo
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences (CAS), Shanghai, China
| | - Liquan Huang
- College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Zhen Ge
- School of Pharmaceutical Sciences, Hangzhou Medical College, Hangzhou, China
| | - Luyang Yu
- Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province of Sir Run Run Shaw Hospital, MOE Laboratory of Biosystems Homeostasis & Protection of College of Life Sciences, Zhejiang University, Hangzhou, China.,College of Life Sciences-iCell Biotechnology Regenerative Biomedicine Laboratory, Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
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15
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Owji AP, Kittredge A, Zhang Y, Yang T. Structure and Function of the Bestrophin family of calcium-activated chloride channels. Channels (Austin) 2021; 15:604-623. [PMID: 34612806 PMCID: PMC8496536 DOI: 10.1080/19336950.2021.1981625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Bestrophins are a family of calcium-activated chloride channels (CaCCs) with relevance to human physiology and a myriad of eye diseases termed "bestrophinopathies". Since the identification of bestrophins as CaCCs nearly two decades ago, extensive studies from electrophysiological and structural biology perspectives have sought to define their key channel features including calcium sensing, gating, inactivation, and anion selectivity. The initial X-ray crystallography studies on the prokaryotic homolog of Best1, Klebsiella pneumoniae (KpBest), and the Best1 homolog from Gallus gallus (chicken Best1, cBest1), laid the foundational groundwork for establishing the architecture of Best1. Recent progress utilizing single-particle cryogenic electron microscopy has further elucidated the molecular mechanism of gating in cBest1 and, separately, the structure of Best2 from Bos taurus (bovine Best2, bBest2). Meanwhile, whole-cell patch clamp, planar lipid bilayer, and other electrophysiologic analyses using these models as well as the human Best1 (hBest1) have provided ample evidence describing the functional properties of the bestrophin channels. This review seeks to consolidate these structural and functional results to paint a broad picture of the underlying mechanisms comprising the bestrophin family's structure-function relationship.
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Affiliation(s)
- Aaron P Owji
- Department of Pharmacology, Columbia University, NY, USA
| | - Alec Kittredge
- Department of Pharmacology, Columbia University, NY, USA
| | - Yu Zhang
- Department of Ophthalmology, Columbia University, NY, USA
| | - Tingting Yang
- Department of Ophthalmology, Columbia University, NY, USA
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16
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Taylor AW, Hsu S, Ng TF. The Role of Retinal Pigment Epithelial Cells in Regulation of Macrophages/Microglial Cells in Retinal Immunobiology. Front Immunol 2021; 12:724601. [PMID: 34484232 PMCID: PMC8414138 DOI: 10.3389/fimmu.2021.724601] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 07/28/2021] [Indexed: 12/28/2022] Open
Abstract
The ocular tissue microenvironment is immune privileged and uses several mechanisms of immunosuppression to prevent the induction of inflammation. Besides being a blood-barrier and source of photoreceptor nutrients, the retinal pigment epithelial cells (RPE) regulate the activity of immune cells within the retina. These mechanisms involve the expression of immunomodulating molecules that make macrophages and microglial cells suppress inflammation and promote immune tolerance. The RPE have an important role in ocular immune privilege to regulate the behavior of immune cells within the retina. Reviewed is the current understanding of how RPE mediate this regulation and the changes seen under pathological conditions.
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Affiliation(s)
- Andrew W Taylor
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
| | - Samuel Hsu
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
| | - Tat Fong Ng
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, United States
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17
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Sun C, Zhou J, Meng X. Primary cilia in retinal pigment epithelium development and diseases. J Cell Mol Med 2021; 25:9084-9088. [PMID: 34448530 PMCID: PMC8500982 DOI: 10.1111/jcmm.16882] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 12/11/2022] Open
Abstract
Retinal pigment epithelium (RPE) is a highly polarized epithelial monolayer lying between the photoreceptor layer and the Bruch membrane. It is essential for vision through participating in many critical activities, including phagocytosis of photoreceptor outer segments, recycling the visual cycle‐related compounds, forming a barrier to control the transport of nutrients, ions, and water, and the removal of waste. Primary cilia are conservatively present in almost all the vertebrate cells and acts as a sensory organelle to control tissue development and homeostasis maintenance. Numerous studies reveal that abnormalities in RPE lead to various retinal diseases, such as age‐related macular degeneration and diabetic macular oedema, but the mechanism of primary cilia in these physiological and pathological activities remains to be elucidated. Herein, we summarize the functions of primary cilia in the RPE development and the mutations of ciliary genes identified in RPE‐related diseases. By highlighting the significance of primary cilia in regulating the physiological and pathological processes of RPE, we aim to provide novel insights for the treatment of RPE‐related retinal diseases.
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Affiliation(s)
- Chunjiao Sun
- College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Institute of Biomedical Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Institute of Biomedical Sciences, Shandong Normal University, Jinan, China
| | - Xiaoqian Meng
- College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Institute of Biomedical Sciences, Shandong Normal University, Jinan, China
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18
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Hanke-Gogokhia C, Lehmann GL, Benedicto I, de la Fuente-Ortega E, Arshavsky VY, Schreiner R, Rodriguez-Boulan E. Apical CLC-2 in retinal pigment epithelium is crucial for survival of the outer retina. FASEB J 2021; 35:e21689. [PMID: 34085737 PMCID: PMC8252757 DOI: 10.1096/fj.202100349r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 12/15/2022]
Abstract
Knockout of the chloride channel protein 2 (CLC‐2; CLCN2) results in fast progressing blindness in mice. Retinal Pigment Epithelium (RPE) and photoreceptors undergo, in parallel, rapid, and profound morphological changes and degeneration. Immunohistochemistry and electron microscopy of the outer retina and electroretinography of the CLC‐2 KO mouse demonstrated normal morphology at postnatal day 2, followed by drastic changes in RPE and photoreceptor morphology and loss of vision during the first postnatal month. To investigate whether the RPE or the photoreceptors are the primary cause of the degeneration, we injected lentiviruses carrying HA‐tagged CLC‐2 with an RPE‐specific promotor in the subretinal space of CLC‐2‐KO mice at the time of eye opening. As expected, CLC‐2‐HA was expressed exclusively in RPE; strikingly, this procedure rescued the degeneration of both RPE and photoreceptors. Light response in transduced eyes was also recovered. Only a fraction of RPE was transduced with the lentivirus; however, the entire RPE monolayer appears healthy, even the RPE cells not expressing the CLC‐2‐HA. Surprisingly, in contrast with previous physiological observations that postulate that CLC‐2 has a basolateral localization in RPE, our immunofluorescence experiments demonstrated CLC‐2 has an apical distribution, facing the subretinal space and the photoreceptor outer segments. Our findings suggest that CLC‐2 does not play the postulated role in fluid transport at the basolateral membrane. Rather, they suggest that CLC‐2 performs a critical homeostatic role in the subretinal compartment involving a chloride regulatory mechanism that is critical for the survival of both RPE and photoreceptors.
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Affiliation(s)
| | | | - Ignacio Benedicto
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Erwin de la Fuente-Ortega
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Ryan Schreiner
- Division of Regenerative Medicine, Ansary Stem Cell Institute, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Enrique Rodriguez-Boulan
- Department of Ophthalmology, Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY, USA
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19
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Shang P, Stepicheva N, Teel K, McCauley A, Fitting CS, Hose S, Grebe R, Yazdankhah M, Ghosh S, Liu H, Strizhakova A, Weiss J, Bhutto IA, Lutty GA, Jayagopal A, Qian J, Sahel JA, Samuel Zigler J, Handa JT, Sergeev Y, Rajala RVS, Watkins S, Sinha D. βA3/A1-crystallin regulates apical polarity and EGFR endocytosis in retinal pigmented epithelial cells. Commun Biol 2021; 4:850. [PMID: 34239035 PMCID: PMC8266859 DOI: 10.1038/s42003-021-02386-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
The retinal pigmented epithelium (RPE) is a monolayer of multifunctional cells located at the back of the eye. High membrane turnover and polarization, including formation of actin-based apical microvilli, are essential for RPE function and retinal health. Herein, we demonstrate an important role for βA3/A1-crystallin in RPE. βA3/A1-crystallin deficiency leads to clathrin-mediated epidermal growth factor receptor (EGFR) endocytosis abnormalities and actin network disruption at the apical side that result in RPE polarity disruption and degeneration. We found that βA3/A1-crystallin binds to phosphatidylinositol transfer protein (PITPβ) and that βA3/A1-crystallin deficiency diminishes phosphatidylinositol 4,5-biphosphate (PI(4,5)P2), thus probably decreasing ezrin phosphorylation, EGFR activation, internalization, and degradation. We propose that βA3/A1-crystallin acquired its RPE function before evolving as a structural element in the lens, and that in the RPE, it modulates the PI(4,5)P2 pool through PITPβ/PLC signaling axis, coordinates EGFR activation, regulates ezrin phosphorylation and ultimately the cell polarity.
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Affiliation(s)
- Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadezda Stepicheva
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kenneth Teel
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Austin McCauley
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | | | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rhonda Grebe
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Anastasia Strizhakova
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Joseph Weiss
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Imran A Bhutto
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gerard A Lutty
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Jiang Qian
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - José-Alain Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Institut de la Vision, INSERM, CNRS, Sorbonne Université, Paris, France
| | - J Samuel Zigler
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - James T Handa
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yuri Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Raju V S Rajala
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Simon Watkins
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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20
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Abstract
The uncontrolled growth of blood vessels is a major pathological factor in human eye diseases that can result in blindness. This effect is termed ocular neovascularization and is seen in diabetic retinopathy, age-related macular degeneration, glaucoma and retinopathy of prematurity. Current treatments for these diseases include laser photocoagulation, topical injection of corticosteroids, intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents and vitreoretinal surgery. Although strategies to inhibit VEGF have proved to be dramatically successful in some clinical studies, there remains the possibility of significant adverse effects regarding the blockade of crucial physiological roles of VEGF and the invasive nature of the treatments. Moreover, it is evident that other pro-angiogenic factors also play important roles in the development of these diseases, as seen in cases in which anti-VEGF therapies have failed. Therefore, new types of effective treatments are required. In this review, we discuss a promising strategy for the treatment of ocular neovascular diseases, i.e., the inhibition of hypoxia-inducible factor (HIF), a master regulator of angiogenesis. We also summarize promising recently investigated HIF inhibitors as treatments for ocular diseases. This review will facilitate more comprehensive approaches to understanding the protective aspects of HIF inhibition in the prevention of ocular diseases.
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21
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Le D, Lim S, Min KW, Park JW, Kim Y, Ha T, Moon KH, Wagner KU, Kim JW. Tsg101 Is Necessary for the Establishment and Maintenance of Mouse Retinal Pigment Epithelial Cell Polarity. Mol Cells 2021; 44:168-178. [PMID: 33795534 PMCID: PMC8019596 DOI: 10.14348/molcells.2021.0027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/02/2021] [Accepted: 03/02/2021] [Indexed: 11/27/2022] Open
Abstract
The retinal pigment epithelium (RPE) forms a monolayer sheet separating the retina and choroid in vertebrate eyes. The polarized nature of RPE is maintained by distributing membrane proteins differentially along apico-basal axis. We found the distributions of these proteins differ in embryonic, post-natal, and mature mouse RPE, suggesting developmental regulation of protein trafficking. Thus, we deleted tumor susceptibility gene 101 (Tsg101), a key component of endosomal sorting complexes required for transport (ESCRT), in embryonic and mature RPE to determine whether ESCRT-mediated endocytic protein trafficking correlated with the establishment and maintenance of RPE polarity. Loss of Tsg101 severely disturbed the polarity of RPE, which forms irregular aggregates exhibiting non-polarized distribution of cell adhesion proteins and activation of epidermal growth factor receptor signaling. These findings suggest that ESCRT-mediated protein trafficking is essential for the development and maintenance of RPE cell polarity.
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Affiliation(s)
- Dai Le
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Soyeon Lim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Kwang Wook Min
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Joon Woo Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Youjoung Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Taejeong Ha
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Kyeong Hwan Moon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Kay-Uwe Wagner
- Department of Oncology, Wayne State University, Detroit, MI 48201, USA
| | - Jin Woo Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
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22
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Jaroszynska N, Harding P, Moosajee M. Metabolism in the Zebrafish Retina. J Dev Biol 2021; 9:10. [PMID: 33804189 PMCID: PMC8006245 DOI: 10.3390/jdb9010010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
Retinal photoreceptors are amongst the most metabolically active cells in the body, consuming more glucose as a metabolic substrate than even the brain. This ensures that there is sufficient energy to establish and maintain photoreceptor functions during and after their differentiation. Such high dependence on glucose metabolism is conserved across vertebrates, including zebrafish from early larval through to adult retinal stages. As the zebrafish retina develops rapidly, reaching an adult-like structure by 72 hours post fertilisation, zebrafish larvae can be used to study metabolism not only during retinogenesis, but also in functionally mature retinae. The interplay between rod and cone photoreceptors and the neighbouring retinal pigment epithelium (RPE) cells establishes a metabolic ecosystem that provides essential control of their individual functions, overall maintaining healthy vision. The RPE facilitates efficient supply of glucose from the choroidal vasculature to the photoreceptors, which produce metabolic products that in turn fuel RPE metabolism. Many inherited retinal diseases (IRDs) result in photoreceptor degeneration, either directly arising from photoreceptor-specific mutations or secondary to RPE loss, leading to sight loss. Evidence from a number of vertebrate studies suggests that the imbalance of the metabolic ecosystem in the outer retina contributes to metabolic failure and disease pathogenesis. The use of larval zebrafish mutants with disease-specific mutations that mirror those seen in human patients allows us to uncover mechanisms of such dysregulation and disease pathology with progression from embryonic to adult stages, as well as providing a means of testing novel therapeutic approaches.
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Affiliation(s)
| | - Philippa Harding
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK;
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK;
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- The Francis Crick Institute, London NW1 1AT, UK
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23
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Eade K, Gantner ML, Hostyk JA, Nagasaki T, Giles S, Fallon R, Harkins-Perry S, Baldini M, Lim EW, Scheppke L, Dorrell MI, Cai C, Baugh EH, Wolock CJ, Wallace M, Berlow RB, Goldstein DB, Metallo CM, Friedlander M, Allikmets R. Serine biosynthesis defect due to haploinsufficiency of PHGDH causes retinal disease. Nat Metab 2021; 3:366-377. [PMID: 33758422 PMCID: PMC8084205 DOI: 10.1038/s42255-021-00361-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 02/10/2021] [Indexed: 02/08/2023]
Abstract
Macular telangiectasia type 2 (MacTel) is a progressive, late-onset retinal degenerative disease linked to decreased serum levels of serine that elevate circulating levels of a toxic ceramide species, deoxysphingolipids (deoxySLs); however, causal genetic variants that reduce serine levels in patients have not been identified. Here we identify rare, functional variants in the gene encoding the rate-limiting serine biosynthetic enzyme, phosphoglycerate dehydrogenase (PHGDH), as the single locus accounting for a significant fraction of MacTel. Under a dominant collapsing analysis model of a genome-wide enrichment analysis of rare variants predicted to impact protein function in 793 MacTel cases and 17,610 matched controls, the PHGDH gene achieves genome-wide significance (P = 1.2 × 10-13) with variants explaining ~3.2% of affected individuals. We further show that the resulting functional defects in PHGDH cause decreased serine biosynthesis and accumulation of deoxySLs in retinal pigmented epithelial cells. PHGDH is a significant locus for MacTel that explains the typical disease phenotype and suggests a number of potential treatment options.
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Affiliation(s)
- Kevin Eade
- Lowy Medical Research Institute, La Jolla, CA, USA
| | | | - Joseph A Hostyk
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | | | - Sarah Giles
- Lowy Medical Research Institute, La Jolla, CA, USA
| | - Regis Fallon
- Lowy Medical Research Institute, La Jolla, CA, USA
| | - Sarah Harkins-Perry
- Lowy Medical Research Institute, La Jolla, CA, USA
- The Scripps Research Institute, La Jolla, CA, USA
| | - Michelle Baldini
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Esther W Lim
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Lea Scheppke
- Lowy Medical Research Institute, La Jolla, CA, USA
| | | | - Carolyn Cai
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Evan H Baugh
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - Charles J Wolock
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - Martina Wallace
- Department of Bioengineering, University of California, San Diego, CA, USA
| | | | - David B Goldstein
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | | | - Martin Friedlander
- Lowy Medical Research Institute, La Jolla, CA, USA
- The Scripps Research Institute, La Jolla, CA, USA
- Scripps Clinic Medical Group, La Jolla, CA, USA
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, NY, USA.
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA.
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24
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Epithelial-Mesenchymal Transition and Senescence in the Retinal Pigment Epithelium of NFE2L2/PGC-1α Double Knock-Out Mice. Int J Mol Sci 2021; 22:ijms22041684. [PMID: 33567500 PMCID: PMC7915526 DOI: 10.3390/ijms22041684] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 02/04/2021] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most prevalent form of irreversible blindness worldwide in the elderly population. In our previous studies, we found that deficiencies in the nuclear factor, erythroid 2 like 2 (NFE2L2) and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) genes caused AMD-like pathological phenotypes in mice. In the present work, we show hijacked epithelial-mesenchymal transition (EMT) due to the common loss of PGC-1α and NFE2L2 (double knock-out, dKO) genes in aged animals. The implanted area was assessed by histology, immunohistochemistry and transmission electron microscopy. Confocal microscopy revealed altered regions in the filamentous actin ring. This contrasted with hexagonal RPE morphology in wild-type mice. The ultrastructural RPE features here illustrated loss of apical microvilli, alteration of cell-cell contact, loss of basal in-folding with deposits on Bruch’s membrane, and excessive lipofuscin deposition in dKO samples. We also found the expression of epithelial-mesenchymal transition transcription factors, such as Snail, Slug, collagen 1, vimentin and OB-cadherin, to be significantly different in dKO RPEs. An increased immunoreactivity of senescence markers p16, DEC1 and HMGB1 was also noted. These findings suggest that EMT and senescence pathways may intersect in the retinas of dKO mice. Both processes can be activated by damage to the RPE, which may be caused by increased oxidative stress resulting from the absence of NFE2L2 and PGC-1α genes, important for antioxidant defense. This dKO model may provide useful tools for studying AMD pathogenesis and evaluating novel therapies for this disease.
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25
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The Impact of Oxidative Stress on Blood-Retinal Barrier Physiology in Age-Related Macular Degeneration. Cells 2021; 10:cells10010064. [PMID: 33406612 PMCID: PMC7823525 DOI: 10.3390/cells10010064] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/26/2020] [Accepted: 12/30/2020] [Indexed: 02/06/2023] Open
Abstract
The blood retinal barrier (BRB) is a fundamental eye component, whose function is to select the flow of molecules from the blood to the retina and vice-versa, and its integrity allows the maintenance of a finely regulated microenvironment. The outer BRB, composed by the choriocapillaris, the Bruch's membrane, and the retinal pigment epithelium, undergoes structural and functional changes in age-related macular degeneration (AMD), the leading cause of blindness worldwide. BRB alterations lead to retinal dysfunction and neurodegeneration. Several risk factors have been associated with AMD onset in the past decades and oxidative stress is widely recognized as a key factor, even if the exact AMD pathophysiology has not been exactly elucidated yet. The present review describes the BRB physiology, the BRB changes occurring in AMD, the role of oxidative stress in AMD with a focus on the outer BRB structures. Moreover, we propose the use of cerium oxide nanoparticles as a new powerful anti-oxidant agent to combat AMD, based on the relevant existing data which demonstrated their beneficial effects in protecting the outer BRB in animal models of AMD.
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26
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Ibuki M, Lee D, Shinojima A, Miwa Y, Tsubota K, Kurihara T. Rice Bran and Vitamin B6 Suppress Pathological Neovascularization in a Murine Model of Age-Related Macular Degeneration as Novel HIF Inhibitors. Int J Mol Sci 2020; 21:ijms21238940. [PMID: 33255657 PMCID: PMC7728083 DOI: 10.3390/ijms21238940] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 02/07/2023] Open
Abstract
Pathological neovascularization in the eye is a leading cause of blindness in all age groups from retinopathy of prematurity (ROP) in children to age-related macular degeneration (AMD) in the elderly. Inhibiting neovascularization via antivascular endothelial growth factor (VEGF) drugs has been used for the effective treatment. However, anti-VEGF therapies may cause development of chorioretinal atrophy as they affect a physiological amount of VEGF essential for retinal homeostasis. Furthermore, anti-VEGF therapies are still ineffective in some cases, especially in patients with AMD. Hypoxia-inducible factor (HIF) is a strong regulator of VEGF induction under hypoxic and other stress conditions. Our previous reports have indicated that HIF is associated with pathological retinal neovascularization in murine models of ROP and AMD, and HIF inhibition suppresses neovascularization by reducing an abnormal increase in VEGF expression. Along with this, we attempted to find novel effective HIF inhibitors from natural foods of our daily lives. Food ingredients were screened for prospective HIF inhibitors in ocular cell lines of 661W and ARPE-19, and a murine AMD model was utilized for examining suppressive effects of the ingredients on retinal neovascularization. As a result, rice bran and its component, vitamin B6 showed inhibitory effects on HIF activation and suppressed VEGF mRNA induction under a CoCl2-induced pseudo-hypoxic condition. Dietary supplement of these significantly suppressed retinal neovascularization in the AMD model. These data suggest that rice bran could have promising therapeutic values in the management of pathological ocular neovascularization.
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Affiliation(s)
- Mari Ibuki
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (M.I.); (D.L.); (A.S.); (Y.M.)
- Department of Ophthalmology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Deokho Lee
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (M.I.); (D.L.); (A.S.); (Y.M.)
- Department of Ophthalmology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ari Shinojima
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (M.I.); (D.L.); (A.S.); (Y.M.)
- Department of Ophthalmology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Yukihiro Miwa
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (M.I.); (D.L.); (A.S.); (Y.M.)
- Department of Ophthalmology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Animal Eye Care•Tokyo Animal Eye Clinic, Tokyo 158-0093, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Tsubota Laboratory, Inc., Tokyo 160-0016, Japan
- Correspondence: (K.T.); (T.K.); Tel.: +81-3-5636-3269 (K.T.); +81-3-5636-3204 (T.K.)
| | - Toshihide Kurihara
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo 160-8582, Japan; (M.I.); (D.L.); (A.S.); (Y.M.)
- Department of Ophthalmology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Correspondence: (K.T.); (T.K.); Tel.: +81-3-5636-3269 (K.T.); +81-3-5636-3204 (T.K.)
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27
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Shao X, Guha S, Lu W, Campagno KE, Beckel JM, Mills JA, Yang W, Mitchell CH. Polarized Cytokine Release Triggered by P2X7 Receptor from Retinal Pigmented Epithelial Cells Dependent on Calcium Influx. Cells 2020; 9:cells9122537. [PMID: 33255431 PMCID: PMC7760537 DOI: 10.3390/cells9122537] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/13/2020] [Accepted: 11/17/2020] [Indexed: 12/20/2022] Open
Abstract
Cytokine release from non-inflammatory cells is a key step in innate immunity, and agonists triggering cytokine release are central in coordinating responses. P2X7 receptor (P2X7R) stimulation by extracellular ATP is best known to active the NLRP3 inflammasome and release IL-1β, but stimulation also leads to release of other cytokines. As cytokine signaling by retinal pigmented epithelial (RPE) cells is implicated in retinal neurodegeneration, the role of P2X7R in release of cytokine IL-6 from RPE cells was investigated. P2X7R stimulation triggered IL-6 release from primary mouse RPE, human iPS-RPE and human ARPE-19 cells. IL-6 release was polarized, with predominant rise across apical membranes. IL-6 release was inhibited by P2X7R antagonists A438079, A839977, and AZ10606120, but not the NRTI lamivudine (3TC), P2X1R antagonist NF279, or P2Y1R antagonist MRS2179. P2X7R-mediated IL-6 release required extracellular Ca2+ and was blocked by Ca2+ chelator BAPTA. IL-6 release and Ca2+ elevation occurred rapidly, consistent with vesicular IL-6 staining in unstimulated cells. P2X7R stimulation did not trigger IL-1β release in these unprimed cells. P2X7R-mediated IL-6 release was enhanced in RPE cells from the ABCA4−/− mouse model of retinal degeneration. In summary, P2X7R stimulation triggers rapid Ca2+-dependent IL-6 release across the apical membrane of RPE cells.
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Affiliation(s)
- Xiaolei Shao
- Shenzhen Eye Hospital, School of Optometry, Shenzhen University, Shenzhen 518060, China;
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
| | - Sonia Guha
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Wennan Lu
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
| | - Keith E. Campagno
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
| | - Jonathan M. Beckel
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jason A. Mills
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA;
- Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wenli Yang
- Department of Medicine and Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Claire H. Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; (S.G.); (J.M.B.)
- Department of Basic and Translational Science, University of Pennsylvania, Philadelphia, PA 19104, USA; (W.L.); (K.E.C.)
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA;
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Correspondence: ; Tel.: +1-215-573-2176
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28
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Zou H, Shan C, Ma L, Liu J, Yang N, Zhao J. Polarity and epithelial-mesenchymal transition of retinal pigment epithelial cells in proliferative vitreoretinopathy. PeerJ 2020; 8:e10136. [PMID: 33150072 PMCID: PMC7583629 DOI: 10.7717/peerj.10136] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Under physiological conditions, retinal pigment epithelium (RPE) is a cellular monolayer composed of mitotically quiescent cells. Tight junctions and adherens junctions maintain the polarity of RPE cells, and are required for cellular functions. In proliferative vitreoretinopathy (PVR), upon retinal tear, RPE cells lose cell-cell contact, undergo epithelial-mesenchymal transition (EMT), and ultimately transform into myofibroblasts, leading to the formation of fibrocellular membranes on both surfaces of the detached retina and on the posterior hyaloids, which causes tractional retinal detachment. In PVR, RPE cells are crucial contributors, and multiple signaling pathways, including the SMAD-dependent pathway, Rho pathway, MAPK pathways, Jagged/Notch pathway, and the Wnt/β-catenin pathway are activated. These pathways mediate the EMT of RPE cells, which play a key role in the pathogenesis of PVR. This review summarizes the current body of knowledge on the polarized phenotype of RPE, the role of cell-cell contact, and the molecular mechanisms underlying the RPE EMT in PVR, emphasizing key insights into potential approaches to prevent PVR.
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Affiliation(s)
- Hui Zou
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Chenli Shan
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Linlin Ma
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Jia Liu
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Ning Yang
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Jinsong Zhao
- Eye Center, The Second Hospital of Jilin University, Changchun, China
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29
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Storm T, Burgoyne T, Futter CE. Membrane trafficking in the retinal pigment epithelium at a glance. J Cell Sci 2020; 133:133/16/jcs238279. [PMID: 32855284 DOI: 10.1242/jcs.238279] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a highly specialised pigmented monolayer sandwiched between the choroid and the photoreceptors in the retina. Key functions of the RPE include transport of nutrients to the neural retina, removal of waste products and water from the retina to the blood, recycling of retinal chromophores, absorption of scattered light and phagocytosis of the tips of the photoreceptor outer segments. These functions place a considerable membrane trafficking burden on the RPE. In this Cell Science at a Glance article and the accompanying poster, we focus on RPE-specific adaptations of trafficking pathways. We outline mechanisms underlying the polarised expression of membrane proteins, melanosome biogenesis and movement, and endocytic trafficking, as well as photoreceptor outer segment phagocytosis and degradation. We also briefly discuss theories of how dysfunction in trafficking pathways contributes to retinal disease.
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Affiliation(s)
- Tina Storm
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Thomas Burgoyne
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Clare E Futter
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
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30
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The Petri Dish-N2B27 Culture Condition Maintains RPE Phenotype by Inhibiting Cell Proliferation and mTOR Activation. J Ophthalmol 2020; 2020:4892978. [PMID: 32855817 PMCID: PMC7443227 DOI: 10.1155/2020/4892978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 11/17/2022] Open
Abstract
Objective To develop a method for the rapid isolation of rat RPE cells with high yield and maintain its epithelial state in modified culture system. Methods The eyeballs were incubated with dispase. The retina was isolated with RPE attached and cut into several pieces. Following a brief incubation in growth medium, large RPE sheets can be harvested rapidly. RPE cells were divided into four groups and cultured for several weeks, that is, (1) in cell culture dishes with 10% FBS containing medium (CC dish-FBS), (2) in petri dishes with 10% FBS containing medium (Petri dish-FBS), (3) in cell culture dishes with N2 and B27 containing medium (CC dish-N2B27), and (4) in petri dishes with N2 and B27 containing medium (Petri dish-N2B27). Morphological and biological characteristics were investigated using light microscopy, Q-PCR, and western blot. Results The retina would curl inwardly during the growth medium incubation period, releasing RPE sheets in the medium. Compared with low density group (5,000 cells/cm2), RPE cells plated at high density (15,000 cells/cm2) can maintain RPE morphology for a more extended period. Meanwhile, plating RPE cells at low density significantly reduced the expression of RPE cell type-specific genes (RPE65, CRALBP, and bestrophin) and increased the expression of EMT-related genes (N-cadherin, fibronectin, and α-SMA), in comparison with the samples from the high density group. The petri dish culture condition reduced cell adhesion and thus inhibited RPE cell proliferation. As compared with other culture conditions, RPE cells in the petri dish-N2B27 condition could maintain RPE phenotype with increased expression of RPE-specific genes and decreased expression of EMT-related genes. The AKT/mTOR pathway was also decreased in petri dish-N2B27 condition. Conclusion The current study provided an alternative method for easy isolation of RPE cells with high yield and maintenance of its epithelial morphology in the petri dish-N2B27 condition.
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31
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Hawkey-Noble A, Umali J, Fowler G, French CR. Expression of three P4-phospholipid flippases-atp11a, atp11b, and atp11c in zebrafish (Danio rerio). Gene Expr Patterns 2020; 36:119115. [PMID: 32344036 DOI: 10.1016/j.gep.2020.119115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 01/30/2023]
Abstract
Cellular membrane asymmetry is a hallmark characteristic of all eukaryotic cells. The balance of phospholipid composition within the cytoplasmic inner leaflet and the extracellular outer leaflet of the plasma membrane (PM) maintains cellular function and vitality. The proper exposure of particular phospholipids is necessary to maintain cellular signalling, controlled apoptosis, and vesicle transportation among other roles. Phospholipid asymmetry is coordinated by P4-type phospholipid transferases (flippases or ATPases). ATP11A, ATP11B, and ATP11C belong to class VI of the P4-flippase family (vertebrates) and are responsible for the movement of phosphatidylserine (PS) from the outer leaflet to the inner leaflet of the PM. To date, there is a lack of knowledge of the tissue specific expression of these three flippases on a whole-organism level in a vertebrate system. Here we have determined the spatial-temporal expression profiles of each gene in a zebrafish model using in situ hybridization and performed comparative phylogenetic analyses with other vertebrates. Our data reveals sequence similarity between vertebrate flippases and specific synteny of zebrafish and human chromosomes. Both atp11b and atp11c are maternally expressed in zebrafish, while zygotic expression analysis demonstrates tissue and temporal specificity for all three genes. atp11a is expressed in the neural crest cells as well as in the developing eye and ear, while atp11b is expressed early in the ventricular epithelial lining and later in the ear. atp11c is expressed in the anterior most rhombomeres of the hindbrain, pharyngeal arches, and liver. Our expression data suggests that each of the three flippases are integral for the development of specific tissues, and aberrant function of either could lead to visual, hearing, neural, or liver dysfunction.
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Affiliation(s)
- Alexia Hawkey-Noble
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, Canada
| | - Jurgienne Umali
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, Canada
| | - Gerissa Fowler
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, Canada
| | - Curtis R French
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, Canada.
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Sinha T, Naash MI, Al-Ubaidi MR. The Symbiotic Relationship between the Neural Retina and Retinal Pigment Epithelium Is Supported by Utilizing Differential Metabolic Pathways. iScience 2020; 23:101004. [PMID: 32252018 PMCID: PMC7132098 DOI: 10.1016/j.isci.2020.101004] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/09/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022] Open
Abstract
The neural retina and retinal pigment epithelium (RPE) maintain a symbiotic metabolic relationship, disruption of which leads to debilitating vision loss. The current study was undertaken to identify the differences in the steady-state metabolite levels and the pathways functioning between bona fide neural retina and RPE. Global metabolomics and cluster analyses identified 650 metabolites differentially modulated between the murine neural retina and RPE. Of these, 387 and 163 were higher in the RPE and the neural retina, respectively. Further analysis coupled with transcript and protein level investigations revealed that under normal physiological conditions, the RPE utilizes the pentose phosphate (>3-fold in RPE), serine (>10-fold in RPE), and sphingomyelin biosynthesis (>5-fold in RPE) pathways. Conversely, the neural retina relied mostly on glycolysis. These results show how the RPE and the neural retina have acquired an efficient, complementary and metabolically diverse symbiotic niche to support each other's distinct functions.
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Affiliation(s)
- Tirthankar Sinha
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.
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Lakkaraju A, Umapathy A, Tan LX, Daniele L, Philp NJ, Boesze-Battaglia K, Williams DS. The cell biology of the retinal pigment epithelium. Prog Retin Eye Res 2020; 78:100846. [PMID: 32105772 PMCID: PMC8941496 DOI: 10.1016/j.preteyeres.2020.100846] [Citation(s) in RCA: 185] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 02/07/2023]
Abstract
The retinal pigment epithelium (RPE), a monolayer of post-mitotic polarized epithelial cells, strategically situated between the photoreceptors and the choroid, is the primary caretaker of photoreceptor health and function. Dysfunction of the RPE underlies many inherited and acquired diseases that cause permanent blindness. Decades of research have yielded valuable insight into the cell biology of the RPE. In recent years, new technologies such as live-cell imaging have resulted in major advancement in our understanding of areas such as the daily phagocytosis and clearance of photoreceptor outer segment tips, autophagy, endolysosome function, and the metabolic interplay between the RPE and photoreceptors. In this review, we aim to integrate these studies with an emphasis on appropriate models and techniques to investigate RPE cell biology and metabolism, and discuss how RPE cell biology informs our understanding of retinal disease.
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Affiliation(s)
- Aparna Lakkaraju
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Ankita Umapathy
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Li Xuan Tan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Lauren Daniele
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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Holmes AC, Zagnoli-Vieira G, Caldecott KW, Semler BL. Effects of TDP2/VPg Unlinkase Activity on Picornavirus Infections Downstream of Virus Translation. Viruses 2020; 12:E166. [PMID: 32023921 PMCID: PMC7077319 DOI: 10.3390/v12020166] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 12/12/2022] Open
Abstract
In this study, we characterized the role of host cell protein tyrosyl-DNA phosphodiesterase 2 (TDP2) activity, also known as VPg unlinkase, in picornavirus infections in a human cell model of infection. TDP2/VPg unlinkase is used by picornaviruses to remove the small polypeptide, VPg (Virus Protein genome-linked, the primer for viral RNA synthesis), from virus genomic RNA. We utilized a CRISPR/Cas-9-generated TDP2 knock out (KO) human retinal pigment epithelial-1 (hRPE-1) cell line, in addition to the wild type (WT) counterpart for our studies. We determined that in the absence of TDP2, virus growth kinetics for two enteroviruses (poliovirus and coxsackievirus B3) were delayed by about 2 h. Virus titers were reduced by ~2 log10 units for poliovirus and 0.5 log10 units for coxsackievirus at 4 hours post-infection (hpi), and by ~1 log10 unit at 6 hpi for poliovirus. However, virus titers were nearly indistinguishable from those of control cells by the end of the infectious cycle. We determined that this was not the result of an alternative source of VPg unlinkase activity being activated in the absence of TPD2 at late times of infection. Viral protein production in TDP2 KO cells was also substantially reduced at 4 hpi for poliovirus infection, consistent with the observed growth kinetics delay, but reached normal levels by 6 hpi. Interestingly, this result differs somewhat from what has been reported previously for the TDP2 KO mouse cell model, suggesting that either cell type or species-specific differences might be playing a role in the observed phenotype. We also determined that catalytically inactive TDP2 does not rescue the growth defect, confirming that TDP2 5' phosphodiesterase activity is required for efficient virus replication. Importantly, we show for the first time that polysomes can assemble efficiently on VPg-linked RNA after the initial round of translation in a cell culture model, but both positive and negative strand RNA production is impaired in the absence of TDP2 at mid-times of infection, indicating that the presence of VPg on the viral RNA affects a step in the replication cycle downstream of translation (e.g., RNA synthesis). In agreement with this conclusion, we found that double-stranded RNA production (a marker of viral RNA synthesis) is delayed in TDP2 KO RPE-1 cells. Moreover, we show that premature encapsidation of nascent, VPg-linked RNA is not responsible for the observed virus growth defect. Our studies provide the first lines of evidence to suggest that either negative- or positive-strand RNA synthesis (or both) is a likely candidate for the step that requires the removal of VPg from the RNA for an enterovirus infection to proceed efficiently.
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Affiliation(s)
- Autumn C. Holmes
- Department of Microbiology & Molecular Genetics and Center for Virus Research, University of California, Irvine, CA 92697, USA;
| | - Guido Zagnoli-Vieira
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK; (G.Z.-V.); (K.W.C.)
| | - Keith W. Caldecott
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK; (G.Z.-V.); (K.W.C.)
| | - Bert L. Semler
- Department of Microbiology & Molecular Genetics and Center for Virus Research, University of California, Irvine, CA 92697, USA;
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Valensi M, Goldman G, Marchant D, Van Den Berghe L, Jonet L, Daruich A, Robert MP, Krejci E, Klein C, Mascarelli F, Versaux-Botteri C, Moulin A, Putterman M, Guimiot F, Molina T, Terris B, Brémond-Gignac D, Behar-Cohen F, Abitbol MM. Sostdc1 is expressed in all major compartments of developing and adult mammalian eyes. Graefes Arch Clin Exp Ophthalmol 2019; 257:2401-2427. [PMID: 31529323 DOI: 10.1007/s00417-019-04462-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/20/2019] [Accepted: 09/04/2019] [Indexed: 01/16/2023] Open
Abstract
PURPOSE This study was conducted in order to study Sostdc1 expression in rat and human developing and adult eyes. METHODS Using the yeast signal sequence trap screening method, we identified the Sostdc1 cDNA encoding a protein secreted by the adult rat retinal pigment epithelium. We determined by in situ hybridization, RT-PCR, immunohistochemistry, and western blot analysis Sostdc1 gene and protein expression in developing and postnatal rat ocular tissue sections. We also investigated Sostdc1 immunohistolocalization in developing and adult human ocular tissues. RESULTS We demonstrated a prominent Sostdc1 gene expression in the developing rat central nervous system (CNS) and eyes at early developmental stages from E10.5 days postconception (dpc) to E13 dpc. Specific Sostdc1 immunostaining was also detected in most adult cells of rat ocular tissue sections. We also identified the rat ocular embryonic compartments characterized by a specific Sostdc1 immunohistostaining and specific Pax6, Sox2, Otx2, and Vsx2 immunohistostaining from embryonic stages E10.5 to E13 dpc. Furthermore, we determined the localization of SOSTDC1 immunoreactivity in ocular tissue sections of developing and adult human eyes. Indeed, we detected SOSTDC1 immunostaining in developing and adult human retinal pigment epithelium (RPE) and neural retina (NR) as well as in several developing and adult human ocular compartments, including the walls of choroidal and scleral vessels. Of utmost importance, we observed a strong SOSTDC1 expression in a pathological ocular specimen of type 2 Peters' anomaly complicated by retinal neovascularization as well in the walls ofother pathological extra-ocular vessels. CONCLUSION: As rat Sostdc1 and human SOSTDC1 are dual antagonists of the Wnt/β-catenin and BMP signaling pathways, these results underscore the potential crucial roles of these pathways and their antagonists, such as Sostdc1 and SOSTDC1, in developing and adult mammalian normal eyes as well as in syndromic and nonsyndromic congenital eye diseases.
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Affiliation(s)
- Maud Valensi
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Gabrielle Goldman
- APHP, Service de Pathologie de L'Hôpital Cochin-Hôtel-Dieu, Université Paris Descartes, 27 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Dominique Marchant
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- Sorbonne Paris Cité, UFR SMBH, Laboratoire Hypoxie et poumons, Université Paris 13, EA 2363, 93017, Bobigny, France
| | - Loïc Van Den Berghe
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- Inserm UMR 1037, CRCT (Cancer Research Center of Toulouse), 31037, Toulouse, France
| | - Laurent Jonet
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Alejandra Daruich
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France
| | - Matthieu P Robert
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France
- COGnition and Action Group, UMR 8257, CNRS, Université Paris Descartes, Paris, France
| | - Eric Krejci
- COGnition and Action Group, UMR 8257, CNRS, Université Paris Descartes, Paris, France
| | - Christophe Klein
- Centre d'Imagerie Cellulaire et de Cytométrie (CICC), Centre de Recherche des Cordeliers (CRC), Université Pierre et Marie Curie - Paris 6, Université Paris Descartes - Paris 5, UMR_S 1138, 75006, Paris, France
| | - Frédéric Mascarelli
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Claudine Versaux-Botteri
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
| | - Alexandre Moulin
- Département de Pathologie, Hôpital Ophtalmique Jules-Gonin , 15, avenue de France, 1004, Lausanne, Switzerland
| | - Marc Putterman
- APHP, Service de Pathologie de l'Hôpital Universitaire Necker-Enfants-Malades, Université Paris Descartes, 149 rue de Sèvres, 75015, Paris, France
| | - Fabien Guimiot
- Unité Fonctionnelle de Foeto-Pathologie, Hôpital Universitaire Robert Debré, 48 Boulevard Serrurier, 75019, Paris, France
| | - Thierry Molina
- APHP, Service de Pathologie de l'Hôpital Universitaire Necker-Enfants-Malades, Université Paris Descartes, 149 rue de Sèvres, 75015, Paris, France
| | - Benoît Terris
- APHP, Service de Pathologie de L'Hôpital Cochin-Hôtel-Dieu, Université Paris Descartes, 27 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Dominique Brémond-Gignac
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France
| | - Francine Behar-Cohen
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France
- AP-HP, Service d'Ophtalmologie, Hôpital Universitaire Cochin-Hôtel-Dieu, 27 rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Marc M Abitbol
- Centre de Recherches des Cordeliers, UMR_S INSERM 1138, Equipe 17, Université Paris Descartes, 15 rue de l'école de médecine, 75006, Paris, France.
- AP-HP, Hôpital Universitaire Necker-Enfants-Malades, Service d'Ophtalmologie, 149 rue de Sèvres, 75015, Paris, France.
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Caceres PS, Rodriguez-Boulan E. Retinal pigment epithelium polarity in health and blinding diseases. Curr Opin Cell Biol 2019; 62:37-45. [PMID: 31518914 DOI: 10.1016/j.ceb.2019.08.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/30/2019] [Accepted: 08/01/2019] [Indexed: 12/11/2022]
Abstract
The polarized phenotype of the retinal pigment epithelium is crucial for the outer retina-blood barrier and support of photoreceptors and underlying choroid, and its disruption plays a central role in degenerative retinopathies. Although the mechanisms of polarization remain mostly unknown, they are fundamental for homeostasis of the outer retina. Recent research is revealing a growing picture of interconnected tissues in the outer retina, with the retinal pigment epithelium at the center. This review discusses how elements of epithelial polarity relate to emerging apical interactions with the neural retina, basolateral cross-talk with the underlying Bruch's membrane and choriocapillaris, and tight junction biology. An integrated view of outer retina physiology is likely to provide insights into the pathogenesis of blinding diseases.
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Affiliation(s)
- Paulo S Caceres
- Weill Cornell Medical College, Department of Ophthalmology, Margaret Dyson Vision Research Institute, New York, NY, 10065, USA.
| | - Enrique Rodriguez-Boulan
- Weill Cornell Medical College, Department of Ophthalmology, Margaret Dyson Vision Research Institute, New York, NY, 10065, USA.
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37
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Milićević N, Duursma A, Ten Asbroek ALMA, Felder-Schmittbuhl MP, Bergen AA. Does the circadian clock make RPE-mediated ion transport "tick" via SLC12A2 (NKCC1)? Chronobiol Int 2019; 36:1592-1598. [PMID: 31441327 DOI: 10.1080/07420528.2019.1653317] [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] [Indexed: 12/20/2022]
Abstract
The presence of a circadian clock in the retinal pigment epithelium (RPE) was discovered recently. However, little is known about mechanisms or processes regulated by the RPE clock. We cultured ARPE-19 monolayers in a transwell culture system, and we found rhythmic mRNA expression of the sodium-potassium-chloride co-transporter SLC12A2. We localized the corresponding protein product, NKCC1, on the apical membrane of ARPE-19 cells. We found that concentrations of sodium, potassium, and chloride oscillated in apical supernatants. The ion concentration gradients between supernatants strongly correlated with SLC12A2 mRNA expression. Our results suggest that the circadian clock regulates ion transport by the RPE via NKCC1 expression.
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Affiliation(s)
- Nemanja Milićević
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives , F-67000 Strasbourg , France.,Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9 , 1105 AZ, Amsterdam , the Netherlands
| | - Angelica Duursma
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9 , 1105 AZ, Amsterdam , the Netherlands
| | - Anneloor L M A Ten Asbroek
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9 , 1105 AZ, Amsterdam , the Netherlands
| | - Marie-Paule Felder-Schmittbuhl
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives , F-67000 Strasbourg , France
| | - Arthur A Bergen
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9 , 1105 AZ, Amsterdam , the Netherlands.,Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9 , 1105 AZ, Amsterdam , the Netherlands.,Department of Retinal Signal Processing, Netherlands Institute for Neuroscience (NIN-KNAW) , 1105 BA, Amsterdam , the Netherlands
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Postnikova O, Poliakov E, Golestaneh N, Rogozin IB, Redmond TM. Stable Intronic Sequences and Exon Skipping Events in the Human RPE65 Gene: Analysis of Expression in Retinal Pigment Epithelium Cells and Cell Culture Models. Front Genet 2019; 10:634. [PMID: 31379919 PMCID: PMC6658614 DOI: 10.3389/fgene.2019.00634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/17/2019] [Indexed: 12/04/2022] Open
Abstract
Currently, there is much interest in intronic sequence-containing long non-coding RNAs and the role of intronic transcription in regulation of cellular metabolism and fate. Several stable intronic sequence RNAs (sisRNAs) were recently implicated in regulation of parental genes. To investigate transcription from introns of the RPE65 gene, we analyzed RNA-seq and Nanopore sequencing data from different cell models of human retinal pigment epithelium (RPE) and native bovine RPE. We discovered putative stable poly-adenylated transcripts with sequences corresponding to intronic regions of the RPE65 gene in the cytoplasm of RPE cells. These stable intronic sequences could be important for RPE65 transcription, splicing or translation. We also analyzed alternative splicing events in RPE65. Frequent exon skipping events involving exons 2, 3, and 7 were detected. The rate of these events was much higher in human RPE cell cultures compared with native RPE , consistent with lack of translation of RPE65 mRNA in cell cultures.
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Affiliation(s)
- Olga Postnikova
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, MD, United States
| | - Eugenia Poliakov
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, MD, United States
| | - Nady Golestaneh
- Departments of Ophthalmology, Neurology, Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC, United States
| | - Igor B Rogozin
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD, United States
| | - T Michael Redmond
- Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, MD, United States
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The Cytoskeleton of the Retinal Pigment Epithelium: from Normal Aging to Age-Related Macular Degeneration. Int J Mol Sci 2019; 20:ijms20143578. [PMID: 31336621 PMCID: PMC6678077 DOI: 10.3390/ijms20143578] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/15/2019] [Accepted: 07/18/2019] [Indexed: 12/15/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a unique epithelium, with major roles which are essential in the visual cycle and homeostasis of the outer retina. The RPE is a monolayer of polygonal and pigmented cells strategically placed between the neuroretina and Bruch membrane, adjacent to the fenestrated capillaries of the choriocapillaris. It shows strong apical (towards photoreceptors) to basal/basolateral (towards Bruch membrane) polarization. Multiple functions are bound to a complex structure of highly organized and polarized intracellular components: the cytoskeleton. A strong connection between the intracellular cytoskeleton and extracellular matrix is indispensable to maintaining the function of the RPE and thus, the photoreceptors. Impairments of these intracellular structures and the regular architecture they maintain often result in a disrupted cytoskeleton, which can be found in many retinal diseases, including age-related macular degeneration (AMD). This review article will give an overview of current knowledge on the molecules and proteins involved in cytoskeleton formation in cells, including RPE and how the cytoskeleton is affected under stress conditions—especially in AMD.
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Primary Cilium-Mediated Retinal Pigment Epithelium Maturation Is Disrupted in Ciliopathy Patient Cells. Cell Rep 2019; 22:189-205. [PMID: 29298421 PMCID: PMC6166245 DOI: 10.1016/j.celrep.2017.12.038] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/08/2017] [Accepted: 12/11/2017] [Indexed: 12/15/2022] Open
Abstract
Primary cilia are sensory organelles that protrude from the cell membrane. Defects in the primary cilium cause ciliopathy disorders, with retinal degeneration as a prominent phenotype. Here, we demonstrate that the retinal pigment epithelium (RPE), essential for photoreceptor development and function, requires a functional primary cilium for complete maturation and that RPE maturation defects in ciliopathies precede photoreceptor degeneration. Pharmacologically enhanced ciliogenesis in wild-type induced pluripotent stem cells (iPSC)-RPE leads to fully mature and functional cells. In contrast, ciliopathy patient-derived iPSC-RPE and iPSC-RPE with a knockdown of ciliary-trafficking protein remain immature, with defective apical processes, reduced functionality, and reduced adult-specific gene expression. Proteins of the primary cilium regulate RPE maturation by simultaneously suppressing canonical WNT and activating PKCδ pathways. A similar cilium-dependent maturation pathway exists in lung epithelium. Our results provide insights into ciliopathy-induced retinal degeneration, demonstrate a developmental role for primary cilia in epithelial maturation, and provide a method to mature iPSC epithelial cells for clinical applications. May-Simera et al. show that primary cilia regulate the maturation and polarization of human iPSC-RPE, mouse RPE, and human iPSC-lung epithelium through canonical WNT suppression and PKCδ activation. RPE cells derived from ciliopathy patients exhibit defective structure and function. These results provide insights into ciliopathy-induced retinal degeneration.
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Léveillard T, Philp NJ, Sennlaub F. Is Retinal Metabolic Dysfunction at the Center of the Pathogenesis of Age-related Macular Degeneration? Int J Mol Sci 2019; 20:ijms20030762. [PMID: 30754662 PMCID: PMC6387069 DOI: 10.3390/ijms20030762] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/04/2019] [Accepted: 02/05/2019] [Indexed: 01/12/2023] Open
Abstract
The retinal pigment epithelium (RPE) forms the outer blood⁻retina barrier and facilitates the transepithelial transport of glucose into the outer retina via GLUT1. Glucose is metabolized in photoreceptors via the tricarboxylic acid cycle (TCA) and oxidative phosphorylation (OXPHOS) but also by aerobic glycolysis to generate glycerol for the synthesis of phospholipids for the renewal of their outer segments. Aerobic glycolysis in the photoreceptors also leads to a high rate of production of lactate which is transported out of the subretinal space to the choroidal circulation by the RPE. Lactate taken up by the RPE is converted to pyruvate and metabolized via OXPHOS. Excess lactate in the RPE is transported across the basolateral membrane to the choroid. The uptake of glucose by cone photoreceptor cells is enhanced by rod-derived cone viability factor (RdCVF) secreted by rods and by insulin signaling. Together, the three cells act as symbiotes: the RPE supplies the glucose from the choroidal circulation to the photoreceptors, the rods help the cones, and both produce lactate to feed the RPE. In age-related macular degeneration this delicate ménage à trois is disturbed by the chronic infiltration of inflammatory macrophages. These immune cells also rely on aerobic glycolysis and compete for glucose and produce lactate. We here review the glucose metabolism in the homeostasis of the outer retina and in macrophages and hypothesize what happens when the metabolism of photoreceptors and the RPE is disturbed by chronic inflammation.
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Affiliation(s)
- Thierry Léveillard
- . Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| | - Nancy J Philp
- . Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - Florian Sennlaub
- . Department of Therapeutics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
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42
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Swarup A, Samuels IS, Bell BA, Han JYS, Du J, Massenzio E, Abel ED, Boesze-Battaglia K, Peachey NS, Philp NJ. Modulating GLUT1 expression in retinal pigment epithelium decreases glucose levels in the retina: impact on photoreceptors and Müller glial cells. Am J Physiol Cell Physiol 2018; 316:C121-C133. [PMID: 30462537 DOI: 10.1152/ajpcell.00410.2018] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The retina is one of the most metabolically active tissues in the body and utilizes glucose to produce energy and intermediates required for daily renewal of photoreceptor cell outer segments. Glucose transporter 1 (GLUT1) facilitates glucose transport across outer blood retinal barrier (BRB) formed by the retinal pigment epithelium (RPE) and the inner BRB formed by the endothelium. We used conditional knockout mice to study the impact of reducing glucose transport across the RPE on photoreceptor and Müller glial cells. Transgenic mice expressing Cre recombinase under control of the Bestrophin1 ( Best1) promoter were bred with Glut1flox/flox mice to generate Tg-Best1-Cre:Glut1flox/flox mice ( RPEΔGlut1). The RPEΔGlut1 mice displayed a mosaic pattern of Cre expression within the RPE that allowed us to analyze mice with ~50% ( RPEΔGlut1m) recombination and mice with >70% ( RPEΔGlut1h) recombination separately. Deletion of GLUT1 from the RPE did not affect its carrier or barrier functions, indicating that the RPE utilizes other substrates to support its metabolic needs thereby sparing glucose for the outer retina. RPEΔGlut1m mice had normal retinal morphology, function, and no cell death; however, where GLUT1 was absent from a span of RPE greater than 100 µm, there was shortening of the photoreceptor cell outer segments. RPEΔGlut1h mice showed outer segment shortening, cell death of photoreceptors, and activation of Müller glial cells. The severe phenotype seen in RPEΔGlut1h mice indicates that glucose transport via the GLUT1 transporter in the RPE is required to meet the anabolic and catabolic requirements of photoreceptors and maintain Müller glial cells in a quiescent state.
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Affiliation(s)
- Aditi Swarup
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Ivy S Samuels
- Louis Stokes Cleveland VA Medical Center , Cleveland, Ohio.,Cole Eye Institute, Cleveland Clinic , Cleveland, Ohio
| | - Brent A Bell
- Department of Ophthalmology, University of Pennsylvania , Philadelphia, Pennsylvania
| | - John Y S Han
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Jianhai Du
- Department of Ophthalmology, Department of Biochemistry, West Virginia University Eye Institute , Morgantown, West Virginia
| | - Erik Massenzio
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University , Philadelphia, Pennsylvania
| | - E Dale Abel
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa , Iowa City, Iowa.,Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, Penn Dental Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Neal S Peachey
- Louis Stokes Cleveland VA Medical Center , Cleveland, Ohio.,Cole Eye Institute, Cleveland Clinic , Cleveland, Ohio.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University , Cleveland, Ohio
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University , Philadelphia, Pennsylvania
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43
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Pao PJ, Emri E, Abdirahman SB, Soorma T, Zeng HH, Hauck SM, Thompson RB, Lengyel I. The effects of zinc supplementation on primary human retinal pigment epithelium. J Trace Elem Med Biol 2018. [PMID: 29523386 DOI: 10.1016/j.jtemb.2018.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Population-based and interventional studies have shown that elevated zinc levels can reduce the progression to advanced age-related macular degeneration. The objective of this study was to assess whether elevated extracellular zinc has a direct effect on retinal pigment epithelial cells (RPE), by examining the phenotype and molecular characteristics of increased extracellular zinc on human primary RPE cells. Monolayers of human foetal primary RPE cells were grown on culture inserts and maintained in medium supplemented with increasing total concentrations of zinc (0, 75, 100, 125 and 150 μM) for up to 4 weeks. Changes in cell viability and differentiation as well as expression and secretion of proteins were investigated. RPE cells developed a confluent monolayer with cobblestone morphology and transepithelial resistance (TER) >200 Ω*cm2 within 4 weeks. There was a zinc concentration-dependent increase in TER and pigmentation, with the largest effects being achieved by the addition of 125 μM zinc to the culture medium, corresponding to 3.4 nM available (free) zinc levels. The cells responded to addition of zinc by significantly increasing the expression of Retinoid Isomerohydrolase (RPE65) gene; cell pigmentation; Premelanosome Protein (PMEL17) immunoreactivity; and secretion of proteins including Apolipoprotein E (APOE), Complement Factor H (CFH), and High-Temperature Requirement A Serine Peptidase 1 (HTRA1) without an effect on cell viability. This study shows that elevated extracellular zinc levels have a significant and direct effect on differentiation and function of the RPE cells in culture, which may explain, at least in part, the positive effects seen in clinical settings. The results also highlight that determining and controlling of available, as opposed to total added, zinc will be essential to be able to compare results obtained in different laboratories.
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Affiliation(s)
- Po-Jung Pao
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
| | - Eszter Emri
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, United Kingdom.
| | - Safiya Bishar Abdirahman
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom.
| | - Talha Soorma
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom.
| | - Hui-Hui Zeng
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, United States.
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health(GmbH), Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
| | - Richard B Thompson
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, United States.
| | - Imre Lengyel
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1 V9EL, United Kingdom; Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, United Kingdom.
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44
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Using spectral-domain optical coherence tomography to evaluate the type and thickness of interdigitation zone band in adult Chinese. Sci Rep 2018; 8:12253. [PMID: 30115984 PMCID: PMC6095864 DOI: 10.1038/s41598-018-30848-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 08/07/2018] [Indexed: 11/21/2022] Open
Abstract
To study types and thickness of interdigitation zone band in adult Chinese subjects, we conducted a cross-sectional study. The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6 ± 9.8 years. 263 people (263eyes) with a mean age of 64.8 years were randomly selected cases without macular diseases included in the study. A detailed ophthalmic examination was performed including SD-OCT for measurement of the thickness of interdigitation zone band. There are two types of interdigitation zone band; the type1 which can distinguish RPE–BM complex in 170 eyes; and the Type 2 which the two layers merged involved 93 eyes. In type1, the mean thickness of the interdigitation zone band was significantly thicker in the foveal center (16.46 ± 2.92 μm), then nasal macular region (16.19 ± 2.69 μm), temporal macular region (15.73 ± 2.68 . μm), superior region (15.72 ± 2.70 μm), and inferior macular region (14.84 ± 2.63 μm) (P all < 0.05). And the mean thickness of the interdigitation zone band in the foveal center associated with the subfoveal choroidal thickness (P = 0.025) and level of education (P = 0.033). The increase in the thickness of the interdigitation zone band may play a role in the pathophysiologic features of various age-related ocular conditions.
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45
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Lynn SA, Keeling E, Dewing JM, Johnston DA, Page A, Cree AJ, Tumbarello DA, Newman TA, Lotery AJ, Ratnayaka JA. A convenient protocol for establishing a human cell culture model of the outer retina. F1000Res 2018; 7:1107. [PMID: 30271583 PMCID: PMC6137423 DOI: 10.12688/f1000research.15409.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/28/2018] [Indexed: 12/12/2022] Open
Abstract
The retinal pigment epithelium (RPE) plays a key role in the pathogenesis of several blinding retinopathies. Alterations to RPE structure and function are reported in Age-related Macular Degeneration, Stargardt and Best disease as well as pattern dystrophies. However, the precise role of RPE cells in disease aetiology remains incompletely understood. Many studies into RPE pathobiology have utilised animal models, which only recapitulate limited disease features. Some studies are also difficult to carry out in animals as the ocular space remains largely inaccessible to powerful microscopes. In contrast, in-vitro models provide an attractive alternative to investigating pathogenic RPE changes associated with age and disease. In this article we describe the step-by-step approach required to establish an experimentally versatile in-vitro culture model of the outer retina incorporating the RPE monolayer and supportive Bruch's membrane (BrM). We show that confluent monolayers of the spontaneously arisen human ARPE-19 cell-line cultured under optimal conditions reproduce key features of native RPE. These models can be used to study dynamic, intracellular and extracellular pathogenic changes using the latest developments in microscopy and imaging technology. We also discuss how RPE cells from human foetal and stem-cell derived sources can be incorporated alongside sophisticated BrM substitutes to replicate the aged/diseased outer retina in a dish. The work presented here will enable users to rapidly establish a realistic in-vitro model of the outer retina that is amenable to a high degree of experimental manipulation which will also serve as an attractive alternative to using animals. This in-vitro model therefore has the benefit of achieving the 3Rs objective of reducing and replacing the use of animals in research. As well as recapitulating salient structural and physiological features of native RPE, other advantages of this model include its simplicity, rapid set-up time and unlimited scope for detailed single-cell resolution and matrix studies.
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Affiliation(s)
- Savannah A. Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
| | - Jennifer M. Dewing
- Clinical and Experimental Sciences, Faculty of Medicine, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
| | - David A. Johnston
- Biomedical Imaging Unit, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
| | - Anton Page
- Biomedical Imaging Unit, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
| | - Angela J. Cree
- Clinical and Experimental Sciences, Faculty of Medicine, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
| | - David A. Tumbarello
- Biological Sciences, Faculty of Natural & Environmental Sciences, Life Sciences Building 85, University of Southampton, Southampton, Hampshire, SO17 1BJ, UK
| | - Tracey A. Newman
- Clinical and Experimental Sciences, Faculty of Medicine, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
| | - Andrew J. Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, Hampshire, SO16 6YD, UK
| | - J. Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, MP 806, Tremona Road, University of Southampton, Southampton, Hampshire, SO16 6YD, UK
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46
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Zhu S, Yam M, Wang Y, Linton JD, Grenell A, Hurley JB, Du J. Impact of euthanasia, dissection and postmortem delay on metabolic profile in mouse retina and RPE/choroid. Exp Eye Res 2018; 174:113-120. [PMID: 29864440 DOI: 10.1016/j.exer.2018.05.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 01/02/2023]
Abstract
Metabolomics studies in the retina and retinal pigment epithelium (RPE) in animal models or postmortem donors are essential to understanding the retinal metabolism and to revealing the underlying mechanisms of retinal degenerative diseases. We have studied how different methods of euthanasia (CO2 or cervical dislocation) different isolation procedures and postmortem delay affect metabolites in mouse retina and RPE/choroid using LC MS/MS and GC MS. Compared with cervical dislocation, CO2 exposure for 5 min dramatically degrades ATP and GTP into purine metabolites in the retina while raising intermediates in glucose metabolism and amino acids in the RPE/choroid. Isolation in cold buffer containing glucose has the least change in metabolites. Postmortem delay time-dependently and differentially impacts metabolites in the retina and RPE/choroid. In the postmortem retina, 18% of metabolites were changed at 0.5 h (h), 41% at 4 h and 51% at 8 h. However, only 6% of metabolites were changed in the postmortem RPE/choroid and it steadily increased to 20% at 8 h. Notably, both postmortem retina and RPE/choroid tissue showed increased purine metabolites. Storage of eyes in cold nutrient-rich medium substantially blocked the postmortem change in the retina and RPE/choroid. In conclusion, our study provides optimized methods to prepare fresh or postmortem retina and RPE/choroid tissue for metabolomics studies.
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Affiliation(s)
- Siyan Zhu
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Michelle Yam
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Yekai Wang
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Jonathan D Linton
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - Allison Grenell
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA; Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
| | - Jianhai Du
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA.
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47
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Shang P, Stepicheva NA, Hose S, Zigler JS, Sinha D. Primary Cell Cultures from the Mouse Retinal Pigment Epithelium. J Vis Exp 2018. [PMID: 29608155 DOI: 10.3791/56997] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a highly polarized multi-functional epithelium that is located between the neural retina and the choroid of the eye. It is a single sheet of pigmented cells that are hexagonally packed and connected by tight junctions. The main functions of the RPE include absorption of light, phagocytosis of the shed photoreceptor outer segments, spatial buffering of ions, transport of nutrients, ions and water as well as active involvement in the visual cycle. With such important and diverse functions, it is critically important to study the biology of RPE cells. A number of RPE cell lines have been established; however, passaged and immortalized cells are known to quickly lose some of the morphological and physiological characteristics of natural RPE cells. Thus, primary cells are more suitable for studying different aspects of RPE cell biology and function. Mouse primary RPE cell culture is very useful to researchers since mouse models are widely used in biological studies, however collecting RPE cells from mouse is also very challenging due to their small size. Here, we present a protocol for establishing primary mouse RPE cell cultures which includes enucleation and dissection of the eyes and isolation of the RPE sheets to yield the cells for culturing. This method enables efficient cell recovery. The RPE cells obtained from two mice can reach confluency on one 12 mm polyester membrane insert pre-loaded in culture plate after one week of culture and display some of the original properties of bona fide RPE cells such as hexagonal shape and pigmentation after two weeks of culture.
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Affiliation(s)
- Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine;
| | | | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine
| | - J Samuel Zigler
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine; Wilmer Eye Institute, The Johns Hopkins University School of Medicine
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48
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Expression and function of connexin 43 protein in mouse and human retinal pigment epithelial cells as hemichannels and gap junction proteins. Exp Eye Res 2018; 168:128-137. [DOI: 10.1016/j.exer.2018.01.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 01/18/2018] [Accepted: 01/18/2018] [Indexed: 01/08/2023]
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49
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Christensen IB, Mogensen EN, Damkier HH, Praetorius J. Choroid plexus epithelial cells express the adhesion protein P-cadherin at cell-cell contacts and syntaxin-4 in the luminal membrane domain. Am J Physiol Cell Physiol 2018; 314:C519-C533. [PMID: 29351408 DOI: 10.1152/ajpcell.00305.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The choroid plexus epithelial cells (CPECs) belong to a small group of polarized cells, where the Na+-K+-ATPase is expressed in the luminal membrane. The basic polarity of the cells is, therefore, still debated. We investigated the subcellular distribution of an array of proteins known to play fundamental roles either in establishing and maintaining basic cell polarity or in the polarized delivery and recycling of plasma membrane proteins. Immunofluorescence histochemical analysis was applied to determine the subcellular localization of apical and basolateral membrane determinants. Mass spectrometry analysis of CPECs isolated by fluorescence-activated cell sorting was applied to determine the expression of specific forms of the proteins. CPECs mainly express the cell-adhesive P-cadherin, which is localized to the lateral membranes. Proteins belonging to the Crumbs and partitioning defective (Par) protein complexes were all localized to the luminal membrane domain. Par-1 and the Scribble complex were localized to the basolateral membrane domain. Lethal(2) giant larvae homolog 2 (Lgl2) labeling was preferentially observed in the luminal membrane domain. Phosphatidylinositol 3,4,5-trisphosphate (PIP3) was immunolocalized to the basolateral membrane domain, while phosphatidylinositol 4,5-bisphosphate (PIP2) staining was most prominent in the luminal membrane domain along with the PIP3 phosphatase, Pten. The apical target-SNARE syntaxin-3 and the basolateral target-SNARE syntaxin-4 were both localized to the apical membrane domain in CPECs, which lack cellular expression of the clathrin adaptor protein AP-1B for basolateral protein recycling. In conclusion, the CPECs are conventionally polarized, but express P-cadherin at cell-cell contacts, and Lgl2 and syntaxin-4 in the luminal plasma membrane domain.
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Affiliation(s)
| | | | | | - Jeppe Praetorius
- Department of Biomedicine, Health, Aarhus University , Aarhus, Denmark
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50
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Khristov V, Wan Q, Sharma R, Lotfi M, Maminishkis A, Bharti K. Polarized Human Retinal Pigment Epithelium Exhibits Distinct Surface Proteome on Apical and Basal Plasma Membranes. Methods Mol Biol 2018; 1722:223-247. [PMID: 29264809 DOI: 10.1007/978-1-4939-7553-2_15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Surface proteins localized on the apical and basal plasma membranes are required for a cell to sense its environment and relay changes in ionic, cytokine, chemokine, and hormone levels to the inside of the cell. In a polarized cell, surface proteins are differentially localized on the apical or the basolateral sides of the cell. The retinal pigment epithelium (RPE) is an example of a polarized cell that performs a variety of functions that are dependent on its polarized state including trafficking of ions, fluid, and metabolites across the RPE monolayer. These functions are absolutely crucial for maintaining the health and integrity of adjacent photoreceptors, the photosensitive cells of the retina. Here we present a series of approaches to identify and validate the polarization state of cultured primary human RPE cells using immunostaining for RPE apical/basolateral markers, polarized cytokine secretion, electrophysiology, fluid transport, phagocytosis, and identification of plasma membrane proteins through cell surface capturing technology. These approaches are currently being used to validate the polarized state and the epithelial phenotype of human induced pluripotent stem (iPS) cell derived RPE cells. This work provides the basis for developing an autologous cell therapy for age-related macular degeneration using patient specific iPS cell derived RPE.
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Affiliation(s)
- Vladimir Khristov
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Qin Wan
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ruchi Sharma
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Mostafa Lotfi
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Arvydas Maminishkis
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kapil Bharti
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Institute of Health, Bethesda, MD, USA.
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