1
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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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2
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Shoda C, Lee D, Miwa Y, Yamagami S, Nakashizuka H, Nimura K, Okamoto K, Kawagishi H, Negishi K, Kurihara T. Inhibition of hypoxia-inducible factors suppresses subretinal fibrosis. FASEB J 2024; 38:e23792. [PMID: 38953555 DOI: 10.1096/fj.202400540rrr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 06/15/2024] [Accepted: 06/24/2024] [Indexed: 07/04/2024]
Abstract
Age-related macular degeneration (AMD) is a common cause of vision loss. The aggressive form of AMD is associated with ocular neovascularization and subretinal fibrosis, representing a responsive outcome against neovascularization mediated by epithelial-mesenchymal transition of retinal pigment epithelium (RPE) cells. A failure of the current treatment (anti-vascular endothelial growth factor therapy) has also been attributed to the progression of subretinal fibrosis. Hypoxia-inducible factors (HIFs) increase gene expressions to promote fibrosis and neovascularization. HIFs act as a central pathway in the pathogenesis of AMD. HIF inhibitors may suppress ocular neovascularization. Nonetheless, further investigation is required to unravel the aspects of subretinal fibrosis. In this study, we used RPE-specific HIFs or von Hippel-Lindau (VHL, a regulator of HIFs) conditional knockout (cKO) mice, along with pharmacological HIF inhibitors, to demonstrate the suppression of subretinal fibrosis. Fibrosis was suppressed by treatments of HIF inhibitors, and similar suppressive effects were detected in RPE-specific Hif1a/Hif2a- and Hif1a-cKO mice. Promotive effects were observed in RPE-specific Vhl-cKO mice, where fibrosis-mediated pathologic processes were evident. Marine products' extracts and their component taurine suppressed fibrosis as HIF inhibitors. Our study shows critical roles of HIFs in the progression of fibrosis, linking them to the potential development of therapeutics for AMD.
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Affiliation(s)
- Chiho Shoda
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Nihon University School of Medicine, Tokyo, Japan
| | - Deokho Lee
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Yukihiro Miwa
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- Aichi Animal Eye Clinic, Nagoya, Aichi, Japan
| | - Satoru Yamagami
- Ophthalmology, Nihon University School of Medicine, Tokyo, Japan
| | | | - Kazumi Nimura
- Shizuoka Prefectural Research Institute of Fishery and Ocean, Shizuoka, Japan
| | - Kazutoshi Okamoto
- Shizuoka Prefectural Research Institute of Fishery and Ocean, Shizuoka, Japan
- Marine Open Innovation Institute, Shizuoka, Japan
| | - Hirokazu Kawagishi
- Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
- Research Institute for Mushroom Science, Shizuoka University, Shizuoka, Japan
| | - Kazuno Negishi
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Toshihide Kurihara
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
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3
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Chen M, Wang Y, Dalal R, Du J, Vollrath D. Alternative oxidase blunts pseudohypoxia and photoreceptor degeneration due to RPE mitochondrial dysfunction. Proc Natl Acad Sci U S A 2024; 121:e2402384121. [PMID: 38865272 PMCID: PMC11194566 DOI: 10.1073/pnas.2402384121] [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: 02/05/2024] [Accepted: 05/15/2024] [Indexed: 06/14/2024] Open
Abstract
Loss of mitochondrial electron transport complex (ETC) function in the retinal pigment epithelium (RPE) in vivo results in RPE dedifferentiation and progressive photoreceptor degeneration, and has been implicated in the pathogenesis of age-related macular degeneration. Xenogenic expression of alternative oxidases in mammalian cells and tissues mitigates phenotypes arising from some mitochondrial electron transport defects, but can exacerbate others. We expressed an alternative oxidase from Ciona intestinalis (AOX) in ETC-deficient murine RPE in vivo to assess the retinal consequences of stimulating coenzyme Q oxidation and respiration without ATP generation. RPE-restricted expression of AOX in this context is surprisingly beneficial. This focused intervention mitigates RPE mTORC1 activation, dedifferentiation, hypertrophy, stress marker expression, pseudohypoxia, and aerobic glycolysis. These RPE cell autonomous changes are accompanied by increased glucose delivery to photoreceptors with attendant improvements in photoreceptor structure and function. RPE-restricted AOX expression normalizes accumulated levels of succinate and 2-hydroxyglutarate in ETC-deficient RPE, and counteracts deficiencies in numerous neural retinal metabolites. These features can be attributed to the activation of mitochondrial inner membrane flavoproteins such as succinate dehydrogenase and proline dehydrogenase, and alleviation of inhibition of 2-oxyglutarate-dependent dioxygenases such as prolyl hydroxylases and epigenetic modifiers. Our work underscores the importance to outer retinal health of coenzyme Q oxidation in the RPE and identifies a metabolic network critical for photoreceptor survival in the context of RPE mitochondrial dysfunction.
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Affiliation(s)
- Ming Chen
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA94305
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV26506
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA94305
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV26506
| | - Douglas Vollrath
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA94305
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA94305
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4
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Grubaugh CR, Dhingra A, Prakash B, Montenegro D, Sparrow JR, Daniele LL, Curcio CA, Bell BA, Hussain MM, Boesze-Battaglia K. Microsomal triglyceride transfer protein is necessary to maintain lipid homeostasis and retinal function. FASEB J 2024; 38:e23522. [PMID: 38445789 PMCID: PMC10949407 DOI: 10.1096/fj.202302491r] [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: 12/02/2023] [Revised: 02/07/2024] [Accepted: 02/16/2024] [Indexed: 03/07/2024]
Abstract
Lipid processing by the retinal pigment epithelium (RPE) is necessary to maintain retinal health and function. Dysregulation of retinal lipid homeostasis due to normal aging or age-related disease triggers lipid accumulation within the RPE, on Bruch's membrane (BrM), and in the subretinal space. In its role as a hub for lipid trafficking into and out of the neural retina, the RPE packages a significant amount of lipid into lipid droplets for storage and into apolipoprotein B (APOB)-containing lipoproteins (Blps) for export. Microsomal triglyceride transfer protein (MTP), encoded by the MTTP gene, is essential for Blp assembly. Herein we test the hypothesis that MTP expression in the RPE is essential to maintain lipid balance and retinal function using the newly generated RPEΔMttp mouse model. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic depletion of Mttp from the RPE results in intracellular lipid accumulation, increased photoreceptor-associated cholesterol deposits, and photoreceptor cell death, and loss of rod but not cone function. RPE-specific reduction in Mttp had no significant effect on plasma lipids and lipoproteins. While APOB was decreased in the RPE, most ocular retinoids remained unchanged, with the exception of the storage form of retinoid, retinyl ester. Thus suggesting that RPE MTP is critical for Blp synthesis and assembly but is not directly involved in plasma lipoprotein metabolism. These studies demonstrate that RPE-specific MTP expression is necessary to establish and maintain retinal lipid homeostasis and visual function.
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Affiliation(s)
- Catharina R. Grubaugh
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anuradha Dhingra
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Binu Prakash
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Diego Montenegro
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY, 10027 USA
| | - Janet R. Sparrow
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY, 10027 USA
| | - Lauren L. Daniele
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brent A. Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104 USA
| | - M. Mahmood Hussain
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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5
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Kocherlakota S, Baes M. Benefits and Caveats in the Use of Retinal Pigment Epithelium-Specific Cre Mice. Int J Mol Sci 2024; 25:1293. [PMID: 38279294 PMCID: PMC10816505 DOI: 10.3390/ijms25021293] [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: 12/18/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 01/28/2024] Open
Abstract
The retinal pigment epithelium (RPE) is an important monolayer of cells present in the outer retina, forming a major part of the blood-retina barrier (BRB). It performs many tasks essential for the maintenance of retinal integrity and function. With increasing knowledge of the retina, it is becoming clear that both common retinal disorders, like age-related macular degeneration, and rare genetic disorders originate in the RPE. This calls for a better understanding of the functions of various proteins within the RPE. In this regard, mice enabling an RPE-specific gene deletion are a powerful tool to study the role of a particular protein within the RPE cells in their native environment, simultaneously negating any potential influences of systemic changes. Moreover, since RPE cells interact closely with adjacent photoreceptors, these mice also provide an excellent avenue to study the importance of a particular gene function within the RPE to the retina as a whole. In this review, we outline and compare the features of various Cre mice created for this purpose, which allow for inducible or non-inducible RPE-specific knockout of a gene of interest. We summarize the various benefits and caveats involved in the use of such mouse lines, allowing researchers to make a well-informed decision on the choice of Cre mouse to use in relation to their research needs.
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Affiliation(s)
| | - Myriam Baes
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
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6
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Chen Y, Bounds SE, Ma X, Karmoker JR, Liu Y, Ma JX, Cai J. Interleukin-17-mediated protective cytokine signaling against degeneration of the retinal pigment epithelium. Proc Natl Acad Sci U S A 2023; 120:e2311647120. [PMID: 38085785 PMCID: PMC10742376 DOI: 10.1073/pnas.2311647120] [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: 07/09/2023] [Accepted: 11/07/2023] [Indexed: 12/18/2023] Open
Abstract
Injuries to the retinal pigment epithelium (RPE) and outer retina often result in the accumulation of retinal microglia within the subretinal space. These subretinal microglia play crucial roles in inflammation and resolution, but the mechanisms governing their functions are still largely unknown. Our previous research highlighted the protective functions of choroidal γδ T cells in response to RPE injury. In the current study, we employed single-cell RNA sequencing approach to characterize the profiles of immune cells in mouse choroid. We found that γδ T cells were the primary producer of interleukin-17 (IL-17) in the choroid. IL-17 signaled through its receptor on the RPE, subsequently triggering the production of interleukin-6. This cascade of cytokines initiated a metabolic reprogramming of subretinal microglia, enhancing their capacity for lipid metabolism. RPE-specific knockout of IL-17 receptor A led to the dysfunction of subretinal microglia and RPE pathology. Collectively, our findings suggest that responding to RPE injury, the choroidal γδ T cells can initiate a protective signaling cascade that ensures the proper functioning of subretinal microglia.
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Affiliation(s)
- Yan Chen
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK73104
| | - Sarah E. Bounds
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK73104
| | - Xiang Ma
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - James Regun Karmoker
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK73104
| | - Yin Liu
- Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, Houston, TX77030
| | - Jian-Xing Ma
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Jiyang Cai
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK73104
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7
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Grubaugh CR, Dhingra A, Prakash B, Montenegro D, Sparrow JR, Daniele LL, Curcio CA, Bell BA, Hussain MM, Boesze-Battaglia K. Microsomal triglyceride transfer protein is necessary to maintain lipid homeostasis and retinal function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570418. [PMID: 38105975 PMCID: PMC10723417 DOI: 10.1101/2023.12.06.570418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Lipid processing by the retinal pigment epithelium (RPE) is necessary to maintain retinal health and function. Dysregulation of retinal lipid homeostasis due to normal aging or to age-related disease triggers lipid accumulation within the RPE, on Bruch's membrane (BrM), and in the subretinal space. In its role as a hub for lipid trafficking into and out of the neural retina, the RPE packages a significant amount of lipid into lipid droplets for storage and into apolipoprotein B (apoB)-containing lipoproteins (Blps) for export. Microsomal triglyceride transfer protein (MTP), encoded by the MTTP gene, is essential for Blp assembly. Herein we test the hypothesis that MTP expression in the RPE is essential to maintain lipid balance and retinal function using the newly generated RPEΔMttp mouse model. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic deletion of Mttp from the RPE results in intracellular lipid accumulation, increased photoreceptor -associated cholesterol deposits and photoreceptor cell death, and loss of rod but not cone function. RPE-specific ablation of Mttp had no significant effect on plasma lipids and lipoproteins. While, apoB was decreased in the RPE, ocular retinoid concentrations remained unchanged. Thus suggesting that RPE MTP is critical for Blp synthesis and assembly but not directly involved in ocular retinoid and plasma lipoprotein metabolism. These studies demonstrate that RPE-specific MTP expression is necessary to establish and maintain retinal lipid homeostasis and visual function.
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Affiliation(s)
- Catharina R. Grubaugh
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anuradha Dhingra
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Binu Prakash
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Diego Montenegro
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY,10027 USA
| | - Janet R. Sparrow
- Department of Ophthalmology and Department of Pathology and Cell Biology, Columbia University, New York, NY,10027 USA
| | - Lauren L. Daniele
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brent A. Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104 USA
| | - M. Mahmood Hussain
- Department of Foundations of Medicine, New York University Grossman Long Island School of Medicine, Mineola, NY, 11501 USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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8
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Tao T, Xu N, Li J, Zhao M, Li X, Huang L. Conditional loss of Ube3d in the retinal pigment epithelium accelerates age-associated alterations in the retina of mice. J Pathol 2023; 261:442-454. [PMID: 37772657 DOI: 10.1002/path.6201] [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: 12/17/2022] [Revised: 07/07/2023] [Accepted: 08/11/2023] [Indexed: 09/30/2023]
Abstract
Several studies have suggested a correlation between the ubiquitin-proteasome system (UPS) and age-related macular degeneration (AMD), with its phenotypic severity ranging from mild visual impairment to blindness, but the mechanism for UPS dysfunction contributing to disease progression is unclear. In this study, we investigated the role of ubiquitin protein ligase E3D (UBE3D) in aging and degeneration in mouse retina. Conditional knockout of Ube3d in the retinal pigment epithelium (RPE) of mice led to progressive and irregular fundus lesions, attenuation of the retinal vascular system, and age-associated deterioration of rod and cone responses. Simultaneously, RPE-specific Ube3d knockout mice also presented morphological changes similar to the histopathological characteristics of human AMD, in which a defective UPS led to RPE abnormalities such as phagocytosis or degradation of metabolites, the interaction with photoreceptor outer segment, and the transport of nutrients or waste products with choroidal capillaries via Bruch's membrane. Moreover, conditional loss of Ube3d resulted in aberrant molecular characterizations associated with the autophagy-lysosomal pathway, oxidative stress damage, and cell-cycle regulation, which are implicated in AMD pathology. Thus, our findings strengthen and expand the impact of UPS dysfunction on retinal pathophysiology during aging, indicating that genetic Ube3d deficiency in the RPE could lead to the abnormal formation of pigment deposits and secondary fundus alterations. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Tianchang Tao
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
- Department of Ophthalmology, The First Affiliated Hospital of Anhui Medical University, Hefei, PR China
| | - Ningda Xu
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
| | - Jiarui Li
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
| | - Mingwei Zhao
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
| | - Xiaoxin Li
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
- Department of Ophthalmology, Xiamen Eye Center of Xiamen University, Xiamen, PR China
| | - Lvzhen Huang
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, PR China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, PR China
- College of Optometry, Peking University Health Science Center, Beijing, PR China
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9
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Kocherlakota S, Das Y, Swinkels D, Vanmunster M, Callens M, Vinckier S, Vaz FM, Sinha D, Van Veldhoven PP, Fransen M, Baes M. The murine retinal pigment epithelium requires peroxisomal β-oxidation to maintain lysosomal function and prevent dedifferentiation. Proc Natl Acad Sci U S A 2023; 120:e2301733120. [PMID: 37862382 PMCID: PMC10614831 DOI: 10.1073/pnas.2301733120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 08/14/2023] [Indexed: 10/22/2023] Open
Abstract
Retinal pigment epithelium (RPE) cells have to phagocytose shed photoreceptor outer segments (POS) on a daily basis over the lifetime of an organism, but the mechanisms involved in the digestion and recycling of POS lipids are poorly understood. Although it was frequently assumed that peroxisomes may play an essential role, this was never investigated. Here, we show that global as well as RPE-selective loss of peroxisomal β-oxidation in multifunctional protein 2 (MFP2) knockout mice impairs the digestive function of lysosomes in the RPE at a very early age, followed by RPE degeneration. This was accompanied by prolonged mammalian target of rapamycin activation, lipid deregulation, and mitochondrial structural anomalies without, however, causing oxidative stress or energy shortage. The RPE degeneration caused secondary photoreceptor death. Notably, the deterioration of the RPE did not occur in an Mfp2/rd1 mutant mouse line, characterized by absent POS shedding. Our findings prove that peroxisomal β-oxidation in the RPE is essential for handling the polyunsaturated fatty acids present in ingested POS and shed light on retinopathy in patients with peroxisomal disorders. Our data also have implications for gene therapy development as they highlight the importance of targeting the RPE in addition to the photoreceptor cells.
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Affiliation(s)
- Sai Kocherlakota
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Yannick Das
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Daniëlle Swinkels
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Maarten Vanmunster
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Manon Callens
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Stefan Vinckier
- Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, Vlaams Insituut voor Biotechnologie, Leuven3000, Belgium
- Department of Oncology, Leuven Cancer Institute, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Frédéric M. Vaz
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam Gastroenterology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam1105AZ, The Netherlands
- Core Facility Metabolomics, Amsterdam University Medical Center, Amsterdam1105AZ, The Netherlands
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA15213
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD21287
| | - Paul P. Van Veldhoven
- Laboratory of Peroxisome Biology and Intracellular Communication, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Marc Fransen
- Laboratory of Peroxisome Biology and Intracellular Communication, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Leuven3000, Belgium
| | - Myriam Baes
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Leuven3000, Belgium
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10
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Kim JM, Min KW, Kim YJ, Smits R, Basler K, Kim JW. Wnt/β-Catenin Signaling Pathway Is Necessary for the Specification but Not the Maintenance of the Mouse Retinal Pigment Epithelium. Mol Cells 2023; 46:441-450. [PMID: 37190767 PMCID: PMC10336276 DOI: 10.14348/molcells.2023.0029] [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: 02/06/2023] [Accepted: 03/19/2023] [Indexed: 05/17/2023] Open
Abstract
β-Catenin (Ctnnb1) has been shown to play critical roles in the development and maintenance of epithelial cells, including the retinal pigment epithelium (RPE). Ctnnb1 is not only a component of intercellular junctions in the epithelium, it also functions as a transcriptional regulator in the Wnt signaling pathway. To identify which of its functional modalities is critically involved in mouse RPE development and maintenance, we varied Ctnnb1 gene content and activity in mouse RPE lineage cells and tested their impacts on mouse eye development. We found that a Ctnnb1 double mutant (Ctnnb1dm), which exhibits impaired transcriptional activity, could not replace Ctnnb1 in the RPE, whereas Ctnnb1Y654E, which has reduced affinity for the junctions, could do so. Expression of the constitutively active Ctnnb1∆ex3 mutant also suppressed the development of RPE, instead facilitating a ciliary cell fate. However, the post-mitotic or mature RPE was insensitive to the loss, inactivation, or constitutive activation of Ctnnb1. Collectively, our results suggest that Ctnnb1 should be maintained within an optimal range to specify RPE through transcriptional regulation of Wnt target genes in the optic neuroepithelium.
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Affiliation(s)
- Jong-Myeong Kim
- Department of Biological Sciences and KAIST Stem Cell Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Kwang Wook Min
- Department of Biological Sciences and KAIST Stem Cell Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - You-Joung Kim
- Department of Biological Sciences and KAIST Stem Cell Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Ron Smits
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Konrad Basler
- Department of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Jin Woo Kim
- Department of Biological Sciences and KAIST Stem Cell Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
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11
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Ning K, Bhuckory MB, Lo CH, Sendayen BE, Kowal TJ, Chen M, Bansal R, Chang KC, Vollrath D, Berbari NF, Mahajan VB, Hu Y, Sun Y. Cilia-associated wound repair mediated by IFT88 in retinal pigment epithelium. Sci Rep 2023; 13:8205. [PMID: 37211572 PMCID: PMC10200793 DOI: 10.1038/s41598-023-35099-3] [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: 12/06/2022] [Accepted: 05/12/2023] [Indexed: 05/23/2023] Open
Abstract
Primary cilia are conserved organelles that integrate extracellular cues into intracellular signals and are critical for diverse processes, including cellular development and repair responses. Deficits in ciliary function cause multisystemic human diseases known as ciliopathies. In the eye, atrophy of the retinal pigment epithelium (RPE) is a common feature of many ciliopathies. However, the roles of RPE cilia in vivo remain poorly understood. In this study, we first found that mouse RPE cells only transiently form primary cilia. We then examined the RPE in the mouse model of Bardet-Biedl Syndrome 4 (BBS4), a ciliopathy associated with retinal degeneration in humans, and found that ciliation in BBS4 mutant RPE cells is disrupted early during development. Next, using a laser-induced injury model in vivo, we found that primary cilia in RPE reassemble in response to laser injury during RPE wound healing and then rapidly disassemble after the repair is completed. Finally, we demonstrated that RPE-specific depletion of primary cilia in a conditional mouse model of cilia loss promoted wound healing and enhanced cell proliferation. In summary, our data suggest that RPE cilia contribute to both retinal development and repair and provide insights into potential therapeutic targets for more common RPE degenerative diseases.
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Affiliation(s)
- Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Mohajeet B Bhuckory
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Chien-Hui Lo
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Brent E Sendayen
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
- Palo Alto Veterans Administration, Palo Alto, CA, USA
| | - Tia J Kowal
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Ming Chen
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Ruchi Bansal
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Kun-Che Chang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Douglas Vollrath
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Nicolas F Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA.
- Palo Alto Veterans Administration, Palo Alto, CA, USA.
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12
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Iker Etchegaray J, Kelley S, Penberthy K, Karvelyte L, Nagasaka Y, Gasperino S, Paul S, Seshadri V, Raymond M, Marco AR, Pinney J, Stremska M, Barron B, Lucas C, Wase N, Fan Y, Unanue E, Kundu B, Burstyn-Cohen T, Perry J, Ambati J, Ravichandran KS. Phagocytosis in the retina promotes local insulin production in the eye. Nat Metab 2023; 5:207-218. [PMID: 36732622 PMCID: PMC10457724 DOI: 10.1038/s42255-022-00728-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 12/16/2022] [Indexed: 02/04/2023]
Abstract
The retina is highly metabolically active, relying on glucose uptake and aerobic glycolysis. Situated in close contact to photoreceptors, a key function of cells in the retinal pigment epithelium (RPE) is phagocytosis of damaged photoreceptor outer segments (POS). Here we identify RPE as a local source of insulin in the eye that is stimulated by POS phagocytosis. We show that Ins2 messenger RNA and insulin protein are produced by RPE cells and that this production correlates with RPE phagocytosis of POS. Genetic deletion of phagocytic receptors ('loss of function') reduces Ins2, whereas increasing the levels of the phagocytic receptor MerTK ('gain of function') increases Ins2 production in male mice. Contrary to pancreas-derived systemic insulin, RPE-derived local insulin is stimulated during starvation, which also increases RPE phagocytosis. Global or RPE-specific Ins2 gene deletion decreases retinal glucose uptake in starved male mice, dysregulates retinal physiology, causes defects in phototransduction and exacerbates photoreceptor loss in a mouse model of retinitis pigmentosa. Collectively, these data identify RPE cells as a phagocytosis-induced local source of insulin in the retina, with the potential to influence retinal physiology and disease.
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Affiliation(s)
- J Iker Etchegaray
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Shannon Kelley
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kristen Penberthy
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Laura Karvelyte
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yosuke Nagasaka
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
| | - Sofia Gasperino
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Soumen Paul
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Vikram Seshadri
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Michael Raymond
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Ana Royo Marco
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Jonathan Pinney
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Marta Stremska
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brady Barron
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Christopher Lucas
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- University of Edinburgh, Edinburgh, UK
| | - Nishikant Wase
- Biomolecular Analysis Facility, University of Virginia, Charlottesville, VA, USA
| | - Yong Fan
- Drexel University, Philadelphia, PA, USA
| | - Emil Unanue
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bijoy Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Tal Burstyn-Cohen
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Justin Perry
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
- Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA.
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel.
- VIB/UGent Inflammation Research Centre, and Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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13
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Gupta S, Lytvynchuk L, Ardan T, Studenovska H, Faura G, Eide L, Znaor L, Erceg S, Stieger K, Motlik J, Bharti K, Petrovski G. Retinal Pigment Epithelium Cell Development: Extrapolating Basic Biology to Stem Cell Research. Biomedicines 2023; 11:310. [PMID: 36830851 PMCID: PMC9952929 DOI: 10.3390/biomedicines11020310] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
The retinal pigment epithelium (RPE) forms an important cellular monolayer, which contributes to the normal physiology of the eye. Damage to the RPE leads to the development of degenerative diseases, such as age-related macular degeneration (AMD). Apart from acting as a physical barrier between the retina and choroidal blood vessels, the RPE is crucial in maintaining photoreceptor (PR) and visual functions. Current clinical intervention to treat early stages of AMD includes stem cell-derived RPE transplantation, which is still in its early stages of evolution. Therefore, it becomes essential to derive RPEs which are functional and exhibit features as observed in native human RPE cells. The conventional strategy is to use the knowledge obtained from developmental studies using various animal models and stem cell-based exploratory studies to understand RPE biogenies and developmental trajectory. This article emphasises such studies and aims to present a comprehensive understanding of the basic biology, including the genetics and molecular pathways of RPE development. It encompasses basic developmental biology and stem cell-based developmental studies to uncover RPE differentiation. Knowledge of the in utero developmental cues provides an inclusive methodology required for deriving RPEs using stem cells.
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Affiliation(s)
- Santosh Gupta
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Institute for Clinical Medicine, Faculty of Medicine, University of Oslo, 0450 Oslo, Norway
| | - Lyubomyr Lytvynchuk
- Department of Ophthalmology, Justus Liebig University Giessen, University Hospital Giessen and Marburg GmbH, 35392 Giessen, Germany
- Karl Landsteiner Institute for Retinal Research and Imaging, 1030 Vienna, Austria
| | - Taras Ardan
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 27721 Libechov, Czech Republic
| | - Hana Studenovska
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 16206 Prague, Czech Republic
| | - Georgina Faura
- Department of Medical Biochemistry, Institute of Clinical Medicine, University of Oslo, 0372 Oslo, Norway
| | - Lars Eide
- Department of Medical Biochemistry, Institute of Clinical Medicine, University of Oslo, 0372 Oslo, Norway
| | - Ljubo Znaor
- Department of Ophthalmology, University of Split School of Medicine and University Hospital Centre, 21000 Split, Croatia
| | - Slaven Erceg
- Research Center “Principe Felipe”, Stem Cell Therapies in Neurodegenerative Diseases Laboratory, 46012 Valencia, Spain
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 11720 Prague, Czech Republic
| | - Knut Stieger
- Department of Ophthalmology, Justus Liebig University Giessen, University Hospital Giessen and Marburg GmbH, 35392 Giessen, Germany
| | - Jan Motlik
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 27721 Libechov, Czech Republic
| | - Kapil Bharti
- Ocular and Stem Cell Translational Research Section, NEI, NIH, Bethesda, MD 20892, USA
| | - Goran Petrovski
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Institute for Clinical Medicine, Faculty of Medicine, University of Oslo, 0450 Oslo, Norway
- Department of Ophthalmology, University of Split School of Medicine and University Hospital Centre, 21000 Split, Croatia
- Department of Ophthalmology, Oslo University Hospital, 0450 Oslo, Norway
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14
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Kocherlakota S, Swinkels D, Van Veldhoven PP, Baes M. Mouse Models to Study Peroxisomal Functions and Disorders: Overview, Caveats, and Recommendations. Methods Mol Biol 2023; 2643:469-500. [PMID: 36952207 DOI: 10.1007/978-1-0716-3048-8_34] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
During the last three decades many mouse lines were created or identified that are deficient in one or more peroxisomal functions. Different methodologies were applied to obtain global, hypomorph, cell type selective, inducible, and knockin mice. Whereas some models closely mimic pathologies in patients, others strongly deviate or no human counterpart has been reported. Often, mice, apparently endowed with a stronger transcriptional adaptation, have to be challenged with dietary additions or restrictions in order to trigger phenotypic changes. Depending on the inactivated peroxisomal protein, several approaches can be taken to validate the loss-of-function. Here, an overview is given of the available mouse models and their most important characteristics.
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Affiliation(s)
- Sai Kocherlakota
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Daniëlle Swinkels
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Paul P Van Veldhoven
- Laboratory of Peroxisome Biology and Intracellular Communication, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Myriam Baes
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
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15
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Gupta U, Ghosh S, Wallace CT, Shang P, Xin Y, Nair AP, Yazdankhah M, Strizhakova A, Ross MA, Liu H, Hose S, Stepicheva NA, Chowdhury O, Nemani M, Maddipatla V, Grebe R, Das M, Lathrop KL, Sahel JA, Zigler JS, Qian J, Ghosh A, Sergeev Y, Handa JT, St Croix CM, Sinha D. Increased LCN2 (lipocalin 2) in the RPE decreases autophagy and activates inflammasome-ferroptosis processes in a mouse model of dry AMD. Autophagy 2023; 19:92-111. [PMID: 35473441 PMCID: PMC9809950 DOI: 10.1080/15548627.2022.2062887] [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: 11/03/2021] [Revised: 03/30/2022] [Accepted: 04/01/2022] [Indexed: 01/09/2023] Open
Abstract
In dry age-related macular degeneration (AMD), LCN2 (lipocalin 2) is upregulated. Whereas LCN2 has been implicated in AMD pathogenesis, the mechanism remains unknown. Here, we report that in retinal pigmented epithelial (RPE) cells, LCN2 regulates macroautophagy/autophagy, in addition to maintaining iron homeostasis. LCN2 binds to ATG4B to form an LCN2-ATG4B-LC3-II complex, thereby regulating ATG4B activity and LC3-II lipidation. Thus, increased LCN2 reduced autophagy flux. Moreover, RPE cells from cryba1 KO, as well as sting1 KO and Sting1Gt mutant mice (models with abnormal iron chelation), showed decreased autophagy flux and increased LCN2, indicative of CGAS- and STING1-mediated inflammasome activation. Live cell imaging of RPE cells with elevated LCN2 also showed a correlation between inflammasome activation and increased fluorescence intensity of the Liperfluo dye, indicative of oxidative stress-induced ferroptosis. Interestingly, both in human AMD patients and in mouse models with a dry AMD-like phenotype (cryba1 cKO and KO), the LCN2 homodimer variant is increased significantly compared to the monomer. Sub-retinal injection of the LCN2 homodimer secreted by RPE cells into NOD-SCID mice leads to retinal degeneration. In addition, we generated an LCN2 monoclonal antibody that neutralizes both the monomer and homodimer variants and rescued autophagy and ferroptosis activities in cryba1 cKO mice. Furthermore, the antibody rescued retinal function in cryba1 cKO mice as assessed by electroretinography. Here, we identify a molecular pathway whereby increased LCN2 elicits pathophysiology in the RPE, cells known to drive dry AMD pathology, thus providing a possible therapeutic strategy for a disease with no current treatment options.Abbreviations: ACTB: actin, beta; Ad-GFP: adenovirus-green fluorescent protein; Ad-LCN2: adenovirus-lipocalin 2; Ad-LCN2-GFP: adenovirus-LCN2-green fluorescent protein; LCN2AKT2: AKT serine/threonine kinase 2; AMBRA1: autophagy and beclin 1 regulator 1; AMD: age-related macular degeneration; ARPE19: adult retinal pigment epithelial cell line-19; Asp278: aspartate 278; ATG4B: autophagy related 4B cysteine peptidase; ATG4C: autophagy related 4C cysteine peptidase; ATG7: autophagy related 7; ATG9B: autophagy related 9B; BLOC-1: biogenesis of lysosomal organelles complex 1; BLOC1S1: biogenesis of lysosomal organelles complex 1 subunit 1; C57BL/6J: C57 black 6J; CGAS: cyclic GMP-AMP synthase; ChQ: chloroquine; cKO: conditional knockout; Cys74: cysteine 74; Dab2: DAB adaptor protein 2; Def: deferoxamine; DHE: dihydroethidium; DMSO: dimethyl sulfoxide; ERG: electroretinography; FAC: ferric ammonium citrate; Fe2+: ferrous; FTH1: ferritin heavy chain 1; GPX: glutathione peroxidase; GST: glutathione S-transferase; H2O2: hydrogen peroxide; His280: histidine 280; IFNL/IFNλ: interferon lambda; IL1B/IL-1β: interleukin 1 beta; IS: Inner segment; ITGB1/integrin β1: integrin subunit beta 1; KO: knockout; LC3-GST: microtubule associated protein 1 light chain 3-GST; C-terminal fusion; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; LCN2: lipocalin 2; mAb: monoclonal antibody; MDA: malondialdehyde; MMP9: matrix metallopeptidase 9; NLRP3: NLR family pyrin domain containing 3; NOD-SCID: nonobese diabetic-severe combined immunodeficiency; OS: outer segment; PBS: phosphate-buffered saline; PMEL/PMEL17: premelanosome protein; RFP: red fluorescent protein; rLCN2: recombinant LCN2; ROS: reactive oxygen species; RPE SM: retinal pigmented epithelium spent medium; RPE: retinal pigment epithelium; RSL3: RAS-selective lethal; scRNAseq: single-cell ribonucleic acid sequencing; SD-OCT: spectral domain optical coherence tomography; shRNA: small hairpin ribonucleic acid; SM: spent medium; SOD1: superoxide dismutase 1; SQSTM1/p62: sequestosome 1; STAT1: signal transducer and activator of transcription 1; STING1: stimulator of interferon response cGAMP interactor 1; TYR: tyrosinase; VCL: vinculin; WT: wild type.
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Affiliation(s)
- Urvi Gupta
- 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
| | - Callen T Wallace
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ying Xin
- Department of Ophthalmology, 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
| | - Anastasia Strizhakova
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Mark A Ross
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadezda A Stepicheva
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Olivia Chowdhury
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Mihir Nemani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Vishnu Maddipatla
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rhonda Grebe
- Department of Ophthalmology, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Manjula Das
- Molecular Immunology, Mazumdar Shaw Medical Foundation, Bengaluru, India
| | - Kira L Lathrop
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA, 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
- Department of Ophthalmology, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiang Qian
- Department of Ophthalmology, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Arkasubhra Ghosh
- GROW Laboratory, Narayana Nethralaya Foundation, Bengaluru, India
| | - Yuri Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - James T Handa
- Department of Ophthalmology, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Claudette M St Croix
- 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
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Ophthalmology, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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16
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Zhang Y, Jeong H, Mori K, Ikeda SI, Shoda C, Miwa Y, Nakai A, Chen J, Ma Z, Jiang X, Torii H, Kubota Y, Negishi K, Kurihara T, Tsubota K. Vascular endothelial growth factor from retinal pigment epithelium is essential in choriocapillaris and axial length maintenance. PNAS NEXUS 2022; 1:pgac166. [PMID: 36714840 PMCID: PMC9802415 DOI: 10.1093/pnasnexus/pgac166] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 08/16/2022] [Indexed: 06/18/2023]
Abstract
Myopia, which prevalence is rapidly increasing, causes visual impairment; however, the onset mechanism of pathological axial length (AL) elongation remains unclear. A highly vascularized choroid between the retinal pigment epithelium (RPE) and sclera not only maintains physiological activities, but also contributes to ocular development and growth regulation. Vascular endothelial growth factor (VEGF) secreted from the RPE to the choroid is essential for retinal function and maintenance of the choriocapillaris. Herein, we demonstrated that the loss of VEGF secreted from the RPE caused abnormal choriocapillaris development and AL elongation, with features similar to those of the lens-induced myopia (LIM) mouse model, whereas VEGF overexpression by knocking-out von Hippel-Lindau (VHL) specific to the RPE expands the choriocapillaris and shortens the AL. Additionally, LDL Receptor Related Protein 2 (LRP2) deletion in the RPE downregulated VEGF expression and leads to pathological AL elongation. Furthermore, high-myopia patients without choriocapillaris demonstrated longer ALs than did those with preserved choriocapillaris. These results suggest that physiological secretion of VEGF from the RPE is required for proper AL development by maintaining the choriocapillaris. The pinpoint application of VEGF to the choriocapillaris may become a potential intervention for the prevention and treatment of axial myopia progression.
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Affiliation(s)
- Yan Zhang
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Heonuk Jeong
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kiwako Mori
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Shin-Ichi Ikeda
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Chiho Shoda
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Nihon University School of Medicine, 30-1 Oyaguchikamicho, Itabashi City, Tokyo 173-8610, Japan
| | - Yukihiro Miwa
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Aichi Animal Eye Clinic, 3 Chome-17-3 Honjitori, Minami Ward, Nagoya, Aichi 457-0074, Japan
| | - Ayaka Nakai
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Nihon University School of Medicine, 30-1 Oyaguchikamicho, Itabashi City, Tokyo 173-8610, Japan
| | - Junhan Chen
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Ziyan Ma
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Xiaoyan Jiang
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Hidemasa Torii
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Yoshiaki Kubota
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kazuno Negishi
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Toshihide Kurihara
- Laboratory of Photobiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
- Tsubota Laboratory Inc., 34 Shinanomachi, 304 Toshin Shinanomachi Ekimae Building, Shinjuku-ku, Tokyo 160-0016, Japan
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17
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Shao A, Lopez AJ, Chen J, Tham A, Javier S, Quiroz A, Frick S, Levine EM, Lloyd KCK, Leonard BC, Murphy CJ, Glaser TM, Moshiri A. Arap1 loss causes retinal pigment epithelium phagocytic dysfunction and subsequent photoreceptor death. Dis Model Mech 2022; 15:276063. [PMID: 35758026 PMCID: PMC9346516 DOI: 10.1242/dmm.049343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 06/16/2022] [Indexed: 11/20/2022] Open
Abstract
Retinitis pigmentosa (RP), a retinal degenerative disease, is the leading cause of heritable blindness. Previously, we described that Arap1−/− mice develop a similar pattern of photoreceptor degeneration. Arap1 is an Arf-directed GTPase-activating protein shown to modulate actin cytoskeletal dynamics. Curiously, Arap1 expression was detected in Müller glia and retinal pigment epithelium (RPE), but not the photoreceptors themselves. In this study, we generated conditional knockout mice for Müller glia/RPE, Müller glia and RPE via targeting Rlbp1, Glast and Vmd2 promoters, respectively, to drive Cre recombinase expression to knock out Arap1. Vmd2-Cre Arap1tm1c/tm1c and Rlbp1-Cre Arap1tm1c/tm1c mice, but not Glast-Cre Arap1tm1c/tm1c mice, recapitulated the phenotype originally observed in germline Arap1−/− mice. Mass spectrometry analysis of human ARAP1 co-immunoprecipitation identified candidate binding partners of ARAP1, revealing potential interactants involved in phagocytosis, cytoskeletal composition, intracellular trafficking and endocytosis. Quantification of outer segment phagocytosis in vivo demonstrated a clear phagocytic defect in Arap1−/− mice compared to Arap1+/+ controls. We conclude that Arap1 expression in RPE is necessary for photoreceptor survival due to its indispensable function in RPE phagocytosis. This article has an associated First Person interview with the first author of the paper. Summary: We provide evidence that Arap1 expression in retinal pigment epithelium (RPE) is essential for maintaining photoreceptor health due to its indispensable role in RPE phagocytosis.
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Affiliation(s)
- Andy Shao
- The University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Antonio Jacobo Lopez
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA
| | - JiaJia Chen
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA
| | - Addy Tham
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA
| | - Seanne Javier
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA
| | - Alejandra Quiroz
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA
| | - Sonia Frick
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA
| | - Edward M Levine
- Department of Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, TN, USA
| | - K C Kent Lloyd
- Mouse Biology Program, U.C. Davis, Davis, CA, USA.,Department of Surgery, School of Medicine, U.C. Davis, Sacramento, CA, USA
| | - Brian C Leonard
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, U.C. Davis, Davis, CA, USA
| | - Christopher J Murphy
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA.,Department of Surgical and Radiological Sciences, School of Veterinary Medicine, U.C. Davis, Davis, CA, USA
| | - Thomas M Glaser
- Department of Cell Biology and Human Anatomy, School of Medicine, U.C. Davis, Davis, CA, USA
| | - Ala Moshiri
- Department of Ophthalmology & Vision Science, School of Medicine, U.C. Davis, USA
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18
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Jiao X, Ma Z, Lei J, Liu P, Cai X, Shahi PK, Chan CC, Fariss R, Pattnaik BR, Dong L, Hejtmancik JF. Retinal Development and Pathophysiology in Kcnj13 Knockout Mice. Front Cell Dev Biol 2022; 9:810020. [PMID: 35096838 PMCID: PMC8790323 DOI: 10.3389/fcell.2021.810020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/10/2021] [Indexed: 11/22/2022] Open
Abstract
Purpose: We constructed and characterized knockout and conditional knockout mice for KCNJ13, encoding the inwardly rectifying K+ channel of the Kir superfamily Kir7.1, mutations in which cause both Snowflake Vitreoretinal Degeneration (SVD) and Retinitis pigmentosa (RP) to further elucidate the pathology of this disease and to develop a potential model system for gene therapy trials. Methods: A Kcnj13 knockout mouse line was constructed by inserting a gene trap cassette expressing beta-galactosidase flanked by FRT sites in intron 1 with LoxP sites flanking exon two and converted to a conditional knockout by FLP recombination followed by crossing with C57BL/6J mice having Cre driven by the VMD2 promoter. Lentiviral replacement of Kcnj13 was driven by the EF1a or VMD2 promoters. Results: Blue-Gal expression is evident in E12.5 brain ventricular choroid plexus, lens, neural retina layer, and anterior RPE. In the adult eye expression is seen in the ciliary body, RPE and choroid. Adult conditional Kcnj13 ko mice show loss of photoreceptors in the outer nuclear layer, inner nuclear layer thinning with loss of bipolar cells, and thinning and disruption of the outer plexiform layer, correlating with Cre expression in the overlying RPE which, although preserved, shows morphological disruption. Fundoscopy and OCT show signs of retinal degeneration consistent with the histology, and photopic and scotopic ERGs are decreased in amplitude or extinguished. Lentiviral based replacement of Kcnj13 resulted in increased ERG c- but not a- or b- wave amplitudes. Conclusion: Ocular KCNJ13 expression starts in the choroid, lens, ciliary body, and anterior retina, while later expression centers on the RPE with no/lower expression in the neuroretina. Although KCNJ13 expression is not required for survival of the RPE, it is necessary for RPE maintenance of the photoreceptors, and loss of the photoreceptor, outer plexiform, and outer nuclear layers occur in adult KCNJ13 cKO mice, concomitant with decreased amplitude and eventual extinguishing of the ERG and signs of retinitis pigmentosa on fundoscopy and OCT. Kcnj13 replacement resulting in recovery of the ERG c- but not a- and b-waves is consistent with the degree of photoreceptor degeneration seen on histology.
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Affiliation(s)
- Xiaodong Jiao
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Jingqi Lei
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - Pinghu Liu
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - Xiaoyu Cai
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - Pawan K Shahi
- Departments of Pediatrics and Ophthalmology and Visual Sciences and the McPherson Eye Research Institute, University of Wisconsin, Madison, AL, United States
| | - Chi-Chao Chan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Robert Fariss
- Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Bikash R Pattnaik
- Departments of Pediatrics and Ophthalmology and Visual Sciences and the McPherson Eye Research Institute, University of Wisconsin, Madison, AL, United States
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
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19
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Huang S, Liu CH, Wang Z, Fu Z, Britton WR, Blomfield AK, Kamenecka TM, Dunaief JL, Solt LA, Chen J. REV-ERBα regulates age-related and oxidative stress-induced degeneration in retinal pigment epithelium via NRF2. Redox Biol 2022; 51:102261. [PMID: 35176707 PMCID: PMC8851379 DOI: 10.1016/j.redox.2022.102261] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/02/2022] [Accepted: 02/05/2022] [Indexed: 11/21/2022] Open
Abstract
Retinal pigment epithelium (RPE) dysfunction and atrophy occur in dry age-related macular degeneration (AMD), often leading to photoreceptor degeneration and vision loss. Accumulated oxidative stress during aging contributes to RPE dysfunction and degeneration. Here we show that the nuclear receptor REV-ERBα, a redox sensitive transcription factor, protects RPE from age-related degeneration and oxidative stress-induced damage. Genetic deficiency of REV-ERBα leads to accumulated oxidative stress, dysfunction and degeneration of RPE, and AMD-like ocular pathologies in aging mice. Loss of REV-ERBα exacerbates chemical-induced RPE damage, and pharmacological activation of REV-ERBα protects RPE from oxidative damage both in vivo and in vitro. REV-ERBα directly regulates transcription of nuclear factor erythroid 2-related factor 2 (NRF2) and its downstream antioxidant enzymes superoxide dismutase 1 (SOD1) and catalase to counter oxidative damage. Moreover, aged mice with RPE specific knockout of REV-ERBα also exhibit accumulated oxidative stress and fundus and RPE pathologies. Together, our results suggest that REV-ERBα is a novel intrinsic protector of the RPE against age-dependent oxidative stress and a new molecular target for developing potential therapies to treat age-related retinal degeneration.
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20
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Chuang JZ, Yang N, Nakajima N, Otsu W, Fu C, Yang HH, Lee MP, Akbar AF, Badea TC, Guo Z, Nuruzzaman A, Hsu KS, Dunaief JL, Sung CH. Retinal pigment epithelium-specific CLIC4 mutant is a mouse model of dry age-related macular degeneration. Nat Commun 2022; 13:374. [PMID: 35042858 PMCID: PMC8766482 DOI: 10.1038/s41467-021-27935-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/21/2021] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly. Dry AMD has unclear etiology and no treatment. Lipid-rich drusen are the hallmark of dry AMD. An AMD mouse model and insights into drusenogenesis are keys to better understanding of this disease. Chloride intracellular channel 4 (CLIC4) is a pleomorphic protein regulating diverse biological functions. Here we show that retinal pigment epithelium (RPE)-specific Clic4 knockout mice exhibit a full spectrum of functional and pathological hallmarks of dry AMD. Multidisciplinary longitudinal studies of disease progression in these mice support a mechanistic model that links RPE cell-autonomous aberrant lipid metabolism and transport to drusen formation.
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Affiliation(s)
- Jen-Zen Chuang
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
| | - Nan Yang
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Nobuyuki Nakajima
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Department of Urology, Tokai University, Kanagawa, Japan
| | - Wataru Otsu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Department of Biomedical Research Laboratory, Gifu Pharmaceutical University, Gifu, Japan
| | - Cheng Fu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Howard Hua Yang
- The Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Maxwell Ping Lee
- The Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Tudor Constantin Badea
- National Eye Institute, National institute of Health, Bethesda, MD, USA
- Research and Development Institute, Transilvania University of Brasov, School of Medicine, Brasov, Romania
| | - Ziqi Guo
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Afnan Nuruzzaman
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Kuo-Shun Hsu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Sloan Kettering Cancer Institute, New York, NY, USA
| | - Joshua L Dunaief
- FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ching-Hwa Sung
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
- Department of Cell and Developmental Biology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
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21
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Sethna S, Scott PA, Giese APJ, Duncan T, Jian X, Riazuddin S, Randazzo PA, Redmond TM, Bernstein SL, Riazuddin S, Ahmed ZM. CIB2 regulates mTORC1 signaling and is essential for autophagy and visual function. Nat Commun 2021; 12:3906. [PMID: 34162842 PMCID: PMC8222345 DOI: 10.1038/s41467-021-24056-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 05/26/2021] [Indexed: 02/06/2023] Open
Abstract
Age-related macular degeneration (AMD) is a multifactorial neurodegenerative disorder. Although molecular mechanisms remain elusive, deficits in autophagy have been associated with AMD. Here we show that deficiency of calcium and integrin binding protein 2 (CIB2) in mice, leads to age-related pathologies, including sub-retinal pigment epithelium (RPE) deposits, marked accumulation of drusen markers APOE, C3, Aβ, and esterified cholesterol, and impaired visual function, which can be rescued using exogenous retinoids. Cib2 mutant mice exhibit reduced lysosomal capacity and autophagic clearance, and increased mTORC1 signaling-a negative regulator of autophagy. We observe concordant molecular deficits in dry-AMD RPE/choroid post-mortem human tissues. Mechanistically, CIB2 negatively regulates mTORC1 by preferentially binding to 'nucleotide empty' or inactive GDP-loaded Rheb. Upregulated mTORC1 signaling has been implicated in lymphangioleiomyomatosis (LAM) cancer. Over-expressing CIB2 in LAM patient-derived fibroblasts downregulates hyperactive mTORC1 signaling. Thus, our findings have significant implications for treatment of AMD and other mTORC1 hyperactivity-associated disorders.
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Affiliation(s)
- Saumil Sethna
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Patrick A Scott
- Department of Ophthalmology & Visual Sciences, University of Louisville, Louisville, KY, USA
| | - Arnaud P J Giese
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Todd Duncan
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sheikh Riazuddin
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Steven L Bernstein
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA.
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
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22
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Rohrer B, Biswal MR, Obert E, Dang Y, Su Y, Zuo X, Fogelgren B, Kondkar AA, Lobo GP, Lipschutz JH. Conditional Loss of the Exocyst Component Exoc5 in Retinal Pigment Epithelium (RPE) Results in RPE Dysfunction, Photoreceptor Cell Degeneration, and Decreased Visual Function. Int J Mol Sci 2021; 22:5083. [PMID: 34064901 PMCID: PMC8151988 DOI: 10.3390/ijms22105083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/29/2021] [Accepted: 05/07/2021] [Indexed: 11/17/2022] Open
Abstract
To characterize the mechanisms by which the highly conserved exocyst trafficking complex regulates eye physiology in zebrafish and mice, we focused on Exoc5 (also known as sec10), a central exocyst component. We analyzed both exoc5 zebrafish mutants and retinal pigmented epithelium (RPE)-specific Exoc5 knockout mice. Exoc5 is present in both the non-pigmented epithelium of the ciliary body and in the RPE. In this study, we set out to establish an animal model to study the mechanisms underlying the ocular phenotype and to establish if loss of visual function is induced by postnatal RPE Exoc5-deficiency. Exoc5-/- zebrafish had smaller eyes, with decreased number of melanocytes in the RPE and shorter photoreceptor outer segments. At 3.5 days post-fertilization, loss of rod and cone opsins were observed in zebrafish exoc5 mutants. Mice with postnatal RPE-specific loss of Exoc5 showed retinal thinning associated with compromised visual function and loss of visual photoreceptor pigments. Abnormal levels of RPE65 together with a reduced c-wave amplitude indicate a dysfunctional RPE. The retinal phenotype in Exoc5-/- mice was present at 20 weeks, but was more pronounced at 27 weeks, indicating progressive disease phenotype. We previously showed that the exocyst is necessary for photoreceptor ciliogenesis and retinal development. Here, we report that exoc5 mutant zebrafish and mice with RPE-specific genetic ablation of Exoc5 develop abnormal RPE pigmentation, resulting in retinal cell dystrophy and loss of visual pigments associated with compromised vision. Together, these data suggest that exocyst-mediated signaling in the RPE is required for RPE structure and function, indirectly leading to photoreceptor degeneration.
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Affiliation(s)
- Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA; (B.R.); (E.O.)
- Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
| | - Manas R. Biswal
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA;
| | - Elisabeth Obert
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA; (B.R.); (E.O.)
| | - Yujing Dang
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
| | - Yanhui Su
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
| | - Xiaofeng Zuo
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
| | - Ben Fogelgren
- Department of Anatomy, Biochemistry, and Physiology, University of Hawaii at Manoa, Honolulu, HI 96813, USA;
| | - Altaf A. Kondkar
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh 11411, Saudi Arabia;
| | - Glenn P. Lobo
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA; (B.R.); (E.O.)
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
- Department of Ophthalmology and Visual Neurosciences, Lions Research Building, 2001 6th Street SE., Room 225, University of Minnesota, Minneapolis, MN 55455, USA
| | - Joshua H. Lipschutz
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
- Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29425, USA
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23
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Choi EH, Suh S, Einstein DE, Leinonen H, Dong Z, Rao SR, Fliesler SJ, Blackshaw S, Yu M, Peachey NS, Palczewski K, Kiser PD. An inducible Cre mouse for studying roles of the RPE in retinal physiology and disease. JCI Insight 2021; 6:146604. [PMID: 33784255 PMCID: PMC8262343 DOI: 10.1172/jci.insight.146604] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/25/2021] [Indexed: 01/04/2023] Open
Abstract
The retinal pigment epithelium (RPE) provides vital metabolic support for retinal photoreceptor cells and is an important player in numerous retinal diseases. Gene manipulation in mice using the Cre-LoxP system is an invaluable tool for studying the genetic basis of these retinal diseases. However, existing RPE-targeted Cre mouse lines have critical limitations that restrict their reliability for studies of disease pathogenesis and treatment, including mosaic Cre expression, inducer-independent activity, off-target Cre expression, and intrinsic toxicity. Here, we report the generation and characterization of a knockin mouse line in which a P2A-CreERT2 coding sequence is fused with the native RPE-specific 65 kDa protein (Rpe65) gene for cotranslational expression of CreERT2. Cre+/– mice were able to recombine a stringent Cre reporter allele with more than 99% efficiency and absolute RPE specificity upon tamoxifen induction at both postnatal days (PD) 21 and 50. Tamoxifen-independent Cre activity was negligible at PD64. Moreover, tamoxifen-treated Cre+/– mice displayed no signs of structural or functional retinal pathology up to 4 months of age. Despite weak RPE65 expression from the knockin allele, visual cycle function was normal in Cre+/– mice. These data indicate that Rpe65CreERT2 mice are well suited for studies of gene function and pathophysiology in the RPE.
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Affiliation(s)
- Elliot H Choi
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, California, USA.,Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Susie Suh
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, California, USA.,Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - David E Einstein
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA.,Research Service, VA Long Beach Healthcare System, Long Beach, California, USA
| | - Henri Leinonen
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, California, USA
| | - Zhiqian Dong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, California, USA
| | - Sriganesh Ramachandra Rao
- Departments of Ophthalmology and Biochemistry, Jacobs School of Medicine and Biomedical Sciences and.,Neuroscience Graduate Program, University at Buffalo, The State University of New York, Buffalo, New York, USA.,Research Service, VA Western New York Healthcare System, Buffalo, New York, USA
| | - Steven J Fliesler
- Departments of Ophthalmology and Biochemistry, Jacobs School of Medicine and Biomedical Sciences and.,Neuroscience Graduate Program, University at Buffalo, The State University of New York, Buffalo, New York, USA.,Research Service, VA Western New York Healthcare System, Buffalo, New York, USA
| | - Seth Blackshaw
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Neal S Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA.,Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, California, USA.,Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA.,Department of Chemistry, School of Physical Sciences, University of California, Irvine, Irvine, California, USA
| | - Philip D Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, California, USA.,Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA.,Research Service, VA Long Beach Healthcare System, Long Beach, California, USA
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24
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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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25
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Ando S, Hashida N, Yamashita D, Kawabata T, Asao K, Kawasaki S, Sakurai K, Yoshimori T, Nishida K. Rubicon regulates A2E-induced autophagy impairment in the retinal pigment epithelium implicated in the pathology of age-related macular degeneration. Biochem Biophys Res Commun 2021; 551:148-154. [PMID: 33740621 DOI: 10.1016/j.bbrc.2021.02.148] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 02/28/2021] [Indexed: 12/24/2022]
Abstract
Waste product deposition and light stress in the retinal pigment epithelium (RPE) are crucial factors in the pathogenesis of various retinal degenerative diseases, including age-related macular degeneration (AMD), a leading cause of vision loss in elderly individuals worldwide. Given that autophagy in the RPE suppresses waste accumulation, determining the molecular mechanism by which autophagy is compromised in degeneration is necessary. Using polarized human RPE sheets, we found that bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E), a major toxic fluorophore of lipofuscin, causes significant impairment of autophagy and the simultaneous upregulation of Rubicon, a negative regulator of autophagy. Importantly, this impairment was reversed in Rubicon-specific siRNA-treated RPE sheets. In a retinal functional analysis using electroretinograms (ERGs), mice with the RPE-specific deletion of Rubicon showed no significant differences from control cre-expressing mice but presented partially but significantly enhanced amplitudes compared with Atg7 knockout mice. We also found that an inflammatory reaction in the retina in response to chronic blue light irradiation was alleviated in mice with the RPE-specific deletion of Rubicon. In summary, we propose that upregulating basal autophagy by targeting Rubicon is beneficial for protecting the RPE from functional damage with ageing and the inflammatory reaction caused by light-induced cellular stress.
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Affiliation(s)
- Satoru Ando
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Ako Research Institute, Otsuka Pharmaceutical Co., Ltd, Ako, Hyogo, Japan
| | - Noriyasu Hashida
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
| | - Daisuke Yamashita
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Ako Research Institute, Otsuka Pharmaceutical Co., Ltd, Ako, Hyogo, Japan
| | - Tsuyoshi Kawabata
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Nagasaki, Japan
| | - Kazunobu Asao
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Satoshi Kawasaki
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Kazushi Sakurai
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Ako Research Institute, Otsuka Pharmaceutical Co., Ltd, Ako, Hyogo, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Kohji Nishida
- Department of Ocular Immunology and Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka, Japan.
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26
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Bullock J, Polato F, Abu-Asab M, Bernardo-Colón A, Aflaki E, Agbaga MP, Becerra SP. Degradation of Photoreceptor Outer Segments by the Retinal Pigment Epithelium Requires Pigment Epithelium-Derived Factor Receptor (PEDF-R). Invest Ophthalmol Vis Sci 2021; 62:30. [PMID: 33605986 PMCID: PMC7900850 DOI: 10.1167/iovs.62.2.30] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/19/2021] [Indexed: 12/28/2022] Open
Abstract
Purpose To examine the contribution of pigment epithelium-derived factor receptor (PEDF-R) to the phagocytosis process. Previously, we identified PEDF-R, the protein encoded by the PNPLA2 gene, as a phospholipase A2 in the retinal pigment epithelium (RPE). During phagocytosis, RPE cells ingest abundant phospholipids and protein in the form of photoreceptor outer segment (POS) tips, which are then hydrolyzed. The role of PEDF-R in RPE phagocytosis is not known. Methods Mice in which PNPLA2 was conditionally knocked out (cKO) in the RPE were generated. Mouse RPE/choroid explants were cultured. Human ARPE-19 cells were transfected with siPNPLA2 silencing duplexes. POSs were isolated from bovine retinas. The phospholipase A2 inhibitor bromoenol lactone was used. Transmission electron microscopy, immunofluorescence, lipid labeling, pulse-chase experiments, western blots, and free fatty acid and β-hydroxybutyrate assays were performed. Results The RPE of the cKO mice accumulated lipids, as well as more abundant and larger rhodopsin particles, compared to littermate controls. Upon POS exposure, RPE explants from cKO mice released less β-hydroxybutyrate compared to controls. After POS ingestion during phagocytosis, rhodopsin degradation was stalled both in cells treated with bromoenol lactone and in PNPLA2-knocked-down cells relative to their corresponding controls. Phospholipase A2 inhibition lowered β-hydroxybutyrate release from phagocytic RPE cells. PNPLA2 knockdown also resulted in a decline in fatty acids and β-hydroxybutyrate release from phagocytic RPE cells. Conclusions PEDF-R downregulation delayed POS digestion during phagocytosis. The findings imply that the efficiency of RPE phagocytosis depends on PEDF-R, thus identifying a novel contribution of this protein to POS degradation in the RPE.
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Affiliation(s)
- Jeanee Bullock
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington DC, United States
| | - Federica Polato
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Mones Abu-Asab
- Section of Histopathology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Alexandra Bernardo-Colón
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Elma Aflaki
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Martin-Paul Agbaga
- Departments of Cell Biology and Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - S. Patricia Becerra
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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27
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Intartaglia D, Giamundo G, Conte I. The Impact of miRNAs in Health and Disease of Retinal Pigment Epithelium. Front Cell Dev Biol 2021; 8:589985. [PMID: 33520981 PMCID: PMC7844312 DOI: 10.3389/fcell.2020.589985] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/17/2020] [Indexed: 12/17/2022] Open
Abstract
MicroRNAs (miRNAs), a class of non-coding RNAs, are essential key players in the control of biological processes in both physiological and pathological conditions. miRNAs play important roles in fine tuning the expression of many genes, which often have roles in common molecular networks. miRNA dysregulation thus renders cells vulnerable to aberrant fluctuations in genes, resulting in degenerative diseases. The retinal pigment epithelium (RPE) is a monolayer of polarized pigmented epithelial cells that resides between the light-sensitive photoreceptors (PR) and the choriocapillaris. The demanding physiological functions of RPE cells require precise gene regulation for the maintenance of retinal homeostasis under stress conditions and the preservation of vision. Thus far, our understanding of how miRNAs function in the homeostasis and maintenance of the RPE has been poorly addressed, and advancing our knowledge is central to harnessing their potential as therapeutic agents to counteract visual impairment. This review focuses on the emerging roles of miRNAs in the function and health of the RPE and on the future exploration of miRNA-based therapeutic approaches to counteract blinding diseases.
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Affiliation(s)
| | | | - Ivan Conte
- Telethon Institute of Genetics and Medicine, Naples, Italy
- Department of Biology, Polytechnic and Basic Sciences School, University of Naples Federico II, Naples, Italy
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28
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Malsy J, Alvarado AC, Lamontagne JO, Strittmatter K, Marneros AG. Distinct effects of complement and of NLRP3- and non-NLRP3 inflammasomes for choroidal neovascularization. eLife 2020; 9:60194. [PMID: 33305736 PMCID: PMC7732340 DOI: 10.7554/elife.60194] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 11/05/2020] [Indexed: 12/16/2022] Open
Abstract
NLRP3 inflammasome activation and complement-mediated inflammation have been implicated in promoting choroidal neovascularization (CNV) in age-related macular degeneration (AMD), but central questions regarding their contributions to AMD pathogenesis remain unanswered. Key open questions are (1) whether NLRP3 inflammasome activation mainly in retinal pigment epithelium (RPE) or rather in non-RPE cells promotes CNV, (2) whether inflammasome activation in CNV occurs via NLRP3 or also through NLRP3-independent mechanisms, and (3) whether complement activation induces inflammasome activation in CNV. Here we show in a neovascular AMD mouse model that NLRP3 inflammasome activation in non-RPE cells but not in RPE cells promotes CNV. We demonstrate that both NLRP3-dependent and NLRP3-independent inflammasome activation mechanisms induce CNV. Finally, we find that complement and inflammasomes promote CNV through independent mechanisms. Our findings uncover an unexpected role of non-NLRP3 inflammasomes for CNV and suggest that combination therapies targeting inflammasomes and complement may offer synergistic benefits to inhibit CNV.
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Affiliation(s)
- Jakob Malsy
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, United States.,Department of Ophthalmology, University of Halle, Halle, Germany
| | - Andrea C Alvarado
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Joseph O Lamontagne
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Karin Strittmatter
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Alexander G Marneros
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, United States
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29
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An efficient inducible RPE-Selective cre transgenic mouse line. Exp Eye Res 2020; 202:108370. [PMID: 33264655 DOI: 10.1016/j.exer.2020.108370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/30/2020] [Accepted: 11/20/2020] [Indexed: 12/22/2022]
Abstract
Cre-mediated modulation of gene function in the murine retinal pigment epithelium (RPE) has been widely used, but current postnatal RPE-selective Cre driver lines suffer from limited recombination efficiency and/or ectopic or mosaic expression. We sought to generate a transgenic mouse line with consistently efficient RPE-selective Cre activity that could be temporally regulated. We used ϕC31 integrase to insert a DNA construct encoding a human BEST1 promoter fragment driving a Cre recombinase estrogen receptor fusion (BEST1-CreERT2) at the Rosa26 locus of C57BL/6J mice. Rosa26BEST1-CreERT2 mice were bred with a tdTomato reporter line and to mice with a Cre-conditional allele of Tfam. 4-hydroxytamoxifen or vehicle was delivered by four consecutive daily intraperitoneal injections. TdTomato was robustly expressed in the RPE of mice of both sexes for inductions beginning at P14 (males 90.7 ± 4.5%, females 84.7 ± 3.2%) and at 7 weeks (males 84.3 ± 7.0%, females 82 ± 3.6%). <0.6% of Muller glia also expressed tdTomato, but no tdTomato fluorescence was observed in other ocular cells or in multiple non-ocular tissues, with the exception of sparse foci in the testis. No evidence of retinal toxicity was observed in mice homozygous for the transgene induced beginning at P14 and assessed at 7-10 months. RPE-selective ablation of Tfam beginning at P14 led to reduced retinal thickness at 8 months of age and diminished retinal electrical responses at 12 months, as expected. These findings demonstrate that we have generated a mouse line with consistently efficient, tamoxifen-mediated postnatal induction of Cre recombination in the RPE and a small fraction of Muller glia. This line should be useful for temporally regulated modulation of gene function in the murine RPE.
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30
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Jiang M, Paniagua AE, Volland S, Wang H, Balaji A, Li DG, Lopes VS, Burgess BL, Williams DS. Microtubule motor transport in the delivery of melanosomes to the actin-rich apical domain of the retinal pigment epithelium. J Cell Sci 2020; 133:jcs242214. [PMID: 32661088 PMCID: PMC7420818 DOI: 10.1242/jcs.242214] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 06/25/2020] [Indexed: 12/20/2022] Open
Abstract
Melanosomes are motile, light-absorbing organelles that are present in pigment cells of the skin and eye. It has been proposed that melanosome localization, in both skin melanocytes and the retinal pigment epithelium (RPE), involves melanosome capture from microtubule motors by an unconventional myosin, which dynamically tethers the melanosomes to actin filaments. Recent studies with melanocytes have questioned this cooperative capture model. Here, we test the model in RPE cells by imaging melanosomes associated with labeled actin filaments and microtubules, and by investigating the roles of different motor proteins. We found that a deficiency in cytoplasmic dynein phenocopies the lack of myosin-7a, in that melanosomes undergo fewer of the slow myosin-7a-dependent movements and are absent from the RPE apical domain. These results indicate that microtubule-based motility is required for the delivery of melanosomes to the actin-rich apical domain and support a capture mechanism that involves both microtubule and actin motors.
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Affiliation(s)
- Mei Jiang
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Antonio E Paniagua
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stefanie Volland
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Hongxing Wang
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Adarsh Balaji
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - David G Li
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Vanda S Lopes
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Barry L Burgess
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - David S Williams
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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31
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Ormel L, Lauritzen KH, Schreiber R, Kunzelmann K, Gundersen V. GABA, but Not Bestrophin-1, Is Localized in Astroglial Processes in the Mouse Hippocampus and the Cerebellum. Front Mol Neurosci 2020; 13:135. [PMID: 32848599 PMCID: PMC7399226 DOI: 10.3389/fnmol.2020.00135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 07/07/2020] [Indexed: 11/13/2022] Open
Abstract
GABA is proposed to act as a gliotransmitter in the brain. Differences in GABA release from astroglia are thought to underlie differences in tonic inhibition between the cerebellum and the CA1 hippocampus. Here we used quantitative immunogold cytochemistry to localize and compare the levels of GABA in astroglia in these brain regions. We found that the density of GABA immunogold particles was similar in delicate processes of Bergman glia in the cerebellum and astrocytes in the CA1 hippocampus. The astrocytic GABA release is proposed to be mediated by, among others, the Ca2+ activated Cl- channel bestrophin-1. The bestrophin-1 antibodies did not show any significant bestrophin-1 signal in the brain of wt mice, nor in bestrophin-1 knockout mice. The bestrophin-1 signal was low both on Western blots and immunofluorescence laser scanning microscopic images. These results suggest that GABA is localized in astroglia, but in similar concentrations in the cerebellum and CA1 hippocampus, and thus cannot account for differences in tonic inhibition between these brain regions. Furthermore, our data seem to suggest that the GABA release from astroglia previously observed in the hippocampus and cerebellum occurs via mechanisms other than bestrophin-1.
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Affiliation(s)
- Lasse Ormel
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Knut H Lauritzen
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Research Institute of Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Rainer Schreiber
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Vidar Gundersen
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Section for Movement Disorders, Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
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32
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Go YM, Zhang J, Fernandes J, Litwin C, Chen R, Wensel TG, Jones DP, Cai J, Chen Y. MTOR-initiated metabolic switch and degeneration in the retinal pigment epithelium. FASEB J 2020; 34:12502-12520. [PMID: 32721041 DOI: 10.1096/fj.202000612r] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/23/2020] [Accepted: 07/07/2020] [Indexed: 02/06/2023]
Abstract
The retinal pigment epithelium (RPE) is a particularly vulnerable tissue to age-dependent degeneration. Over the life span, the RPE develops an expanded endo-lysosomal compartment to maintain the high efficiency of phagocytosis and degradation of photoreceptor outer segments (POS) necessary for photoreceptor survival. As the assembly and activation of the mechanistic target of rapamycin complex 1 (mTORC1) occur on the lysosome surface, increased lysosome mass with aging leads to higher mTORC1 activity. The functional consequences of hyperactive mTORC1 in the RPE are unclear. In the current study, we used integrated high-resolution metabolomic and genomic approaches to examine mice with RPE-specific deletion of the tuberous sclerosis 1 (Tsc1) gene which encodes an upstream suppressor of mTORC1. Our data show that RPE cells with constitutively high mTORC1 activity were reprogramed to be hyperactive in glucose and lipid metabolism. Lipolysis was suppressed, mitochondrial carnitine shuttle was inhibited, while genes involved in fatty acid (FA) biosynthesis were upregulated. The metabolic changes occurred prior to structural changes of RPE and retinal degeneration. These findings have revealed cellular events and intrinsic mechanisms that contribute to lipid accumulation in the RPE cells during aging and age-related degeneration.
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Affiliation(s)
- Young-Mi Go
- Department of Medicine, Emory University, Atlanta, GA, USA
| | - Jing Zhang
- Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA
| | - Jolyn Fernandes
- Department of Medicine, Emory University, Atlanta, GA, USA.,Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Christopher Litwin
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Rui Chen
- Department of Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Biochemistry, Baylor College of Medicine, Houston, TX, USA
| | - Theodore G Wensel
- Department of Biochemistry, Baylor College of Medicine, Houston, TX, USA
| | - Dean P Jones
- Department of Medicine, Emory University, Atlanta, GA, USA
| | - Jiyang Cai
- Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA.,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Yan Chen
- Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA.,Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Department of Biochemistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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33
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Miyagishima KJ, Zhang C, Malechka VV, Bharti K, Li W. Direct-Coupled Electroretinogram (DC-ERG) for Recording the Light-Evoked Electrical Responses of the Mouse Retinal Pigment Epithelium. J Vis Exp 2020. [PMID: 32744516 DOI: 10.3791/61491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The retinal pigment epithelium (RPE) is a specialized monolayer of cells strategically located between the retina and the choriocapillaris that maintain the overall health and structural integrity of the photoreceptors. The RPE is polarized, exhibiting apically and basally located receptors or channels, and performs vectoral transport of water, ions, metabolites, and secretes several cytokines. In vivo noninvasive measurements of RPE function can be made using direct-coupled ERGs (DC-ERGs). The methodology behind the DC-ERG was pioneered by Marmorstein, Peachey, and colleagues using a custom-built stimulation recording system and later demonstrated using a commercially available system. The DC-ERG technique uses glass capillaries filled with Hank's buffered salt solution (HBSS) to measure the slower electrical responses of the RPE elicited from light-evoked concentration changes in the subretinal space due to photoreceptor activity. The prolonged light stimulus and length of the DC-ERG recording make it vulnerable to drift and noise resulting in a low yield of useable recordings. Here, we present a fast, reliable method for improving the stability of the recordings while reducing noise by using vacuum pressure to reduce/eliminate bubbles that result from outgassing of the HBSS and electrode holder. Additionally, power line artifacts are attenuated using a voltage regulator/power conditioner. We include the necessary light stimulation protocols for a commercially available ERG system as well as scripts for analysis of the DC-ERG components: c-wave, fast oscillation, light peak, and off response. Due to the improved ease of recordings and rapid analysis workflow, this simplified protocol is particularly useful in measuring age-related changes in RPE function, disease progression, and in the assessment of pharmacological intervention.
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Affiliation(s)
| | - Congxiao Zhang
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institutes of Health
| | - Volha V Malechka
- Human Visual Function Core, National Eye Institute, National Institutes of Health
| | - Kapil Bharti
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institutes of Health
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health;
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34
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Lu Q, Scott PA, Vukmanic EV, Kaplan HJ, Dean DC, Li Q. Yap1 is required for maintenance of adult RPE differentiation. FASEB J 2020; 34:6757-6768. [PMID: 32223016 DOI: 10.1096/fj.201903234r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/21/2020] [Accepted: 03/14/2020] [Indexed: 12/22/2022]
Abstract
Nuclear YAP1 plays a critical role in regulation of stem cell proliferation, tissue regeneration, and organ size in many types of epithelia. Due to rapid turnover of most epithelial cell types, the cytoplasmic function of YAP1 in epithelial cells has not been well studied. The retinal pigment epithelium (RPE) is a highly polarized epithelial cell type maintained at a senescence state, and offers an ideal cell model to study the active role of YAP1 in maintenance of the adult epithelial phenotype. Here, we show that the cytoplasmic function of YAP1 is essential to maintain adult RPE differentiation. Knockout of Yap1 in the adult mouse RPE caused cell depolarization and tight junction breakdown, and led to inhibition of RPE65 expression, diminishment of RPE pigments, and retraction of microvilli and basal infoldings. These changes in RPE further prompted the loss of adjacent photoreceptor outer segments and photoreceptor death, which eventually led to decline of visual function in older mice between 6 and 12 months of age. Furthermore, nuclear β-catenin and its activity were significantly increased in mutant RPE. These results suggest that YAP1 plays an important role in active inhibition of Wnt/β-catenin signaling, and is essential for downregulation of β-catenin nuclear activity and prevention of dedifferentiation of adult RPE.
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Affiliation(s)
- Qingxian Lu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY, USA
| | - Patrick A Scott
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY, USA
| | - Eric V Vukmanic
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY, USA
| | - Henry J Kaplan
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY, USA
| | - Douglas C Dean
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY, USA
| | - Qiutang Li
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY, USA
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35
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Ibuki M, Shoda C, Miwa Y, Ishida A, Tsubota K, Kurihara T. Lactoferrin Has a Therapeutic Effect via HIF Inhibition in a Murine Model of Choroidal Neovascularization. Front Pharmacol 2020; 11:174. [PMID: 32180725 PMCID: PMC7059857 DOI: 10.3389/fphar.2020.00174] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/07/2020] [Indexed: 12/30/2022] Open
Abstract
Background Lactoferrin, a type of glycoprotein, is contained in exocrine fluids such as tears, breast milk, sweat, and saliva, and is known to have anti-microbial, antioxidant, and anti-cancer effects. In the ophthalmological field, topical administration of lactoferrin has been reported to have a therapeutic effect in a murine dry eye model. Hypoxia-inducible factor (HIF) regulates various gene expressions under hypoxia, including vascular endothelial growth factor (VEGF), and is considered as an alternative target for neovascular ocular diseases such as age-related macular degeneration (AMD). We previously screened natural products and identified lactoferrin as a novel HIF inhibitor. In this study, we confirmed that lactoferrin has an HIF inhibitory effect and a therapeutic effect in a murine model of neovascular AMD. Methods HIF inhibitory effects of lactoferrin were evaluated using a luciferase assay and western blotting in vitro. The quantified volume of choroidal neovascularization (CNV) induced by laser irradiation was compared with oral lactoferrin administration or conditional tissue specific Hif1a knockout mice. Results Lactoferrin administration showed a significant HIF inhibitory effect in the retinal neuronal cells. Oral administration of lactoferrin or conditional Hif1a gene deletion significantly reduced CNV volume compared to controls. Conclusions Lactoferrin has a therapeutic effect in a laser CNV model by suppressing the retinal HIF activity.
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Affiliation(s)
- Mari Ibuki
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Chiho Shoda
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Nihon University, Tokyo, Japan
| | - Yukihiro Miwa
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Ayako Ishida
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
| | - Kazuo Tsubota
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan.,Tsubota Laboratory, Inc., Tokyo, Japan
| | - Toshihide Kurihara
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
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36
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Han JYS, Kinoshita J, Bisetto S, Bell BA, Nowak RA, Peachey NS, Philp NJ. Role of monocarboxylate transporters in regulating metabolic homeostasis in the outer retina: Insight gained from cell-specific Bsg deletion. FASEB J 2020; 34:5401-5419. [PMID: 32112484 DOI: 10.1096/fj.201902961r] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/29/2020] [Accepted: 02/07/2020] [Indexed: 02/06/2023]
Abstract
The neural retina metabolizes glucose through aerobic glycolysis generating large amounts of lactate. Lactate flux into and out of cells is regulated by proton-coupled monocarboxylate transporters (MCTs), which are encoded by members of the Slc16a family. MCT1, MCT3, and MCT4 are expressed in the retina and require association with the accessory protein basigin, encoded by Bsg, for maturation and trafficking to the plasma membrane. Bsg-/- mice have severely reduced electroretinograms (ERGs) and progressive photoreceptor degeneration, which is presumed to be driven by metabolic dysfunction resulting from loss of MCTs. To understand the basis of the Bsg-/- phenotype, we generated mice with conditional deletion of Bsg in rods (RodΔBsg), cones (Cone∆Bsg), or retinal pigment epithelial cells (RPEΔBsg). RodΔBsg mice showed a progressive loss of photoreceptors, while ConeΔBsg mice did not display a degenerative phenotype. The RPEΔBsg mice developed a distinct phenotype characterized by severely reduced ERG responses as early as 4 weeks of age. The loss of lactate transporters from the RPE most closely resembled the phenotype of the Bsg-/- mouse, suggesting that the regulation of lactate levels in the RPE and the subretinal space is essential for the viability and function of photoreceptors.
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Affiliation(s)
- John Y S Han
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Sara Bisetto
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Brent A Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Romana A Nowak
- Animal Sciences, University of Illinois at Urbana-Champaign, Urbana-Champaign, IL, USA
| | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, 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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38
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Klee K, Storti F, Barben M, Samardzija M, Langmann T, Dunaief J, Grimm C. Systemic knockout of Tspo in mice does not affect retinal morphology, function and susceptibility to degeneration. Exp Eye Res 2019; 188:107816. [PMID: 31562844 DOI: 10.1016/j.exer.2019.107816] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 12/11/2022]
Abstract
Translocator protein (18 kDa) (TSPO) is a mitochondrial protein expressed by reactive microglia and astrocytes at the site of neuronal injury. Although TSPO function has not been fully determined, synthetic TSPO ligands have beneficial effects on different pathologies of the central nervous system, including the retina. Here, we studied the pattern of Tspo expression in the aging human retina and in two mouse models of retinal degeneration. Using a newly generated Tspo-KO mouse, we investigated the impact of the lack of TSPO on retinal morphology, function and susceptibility to degeneration. We show that TSPO was expressed in both human and mouse retina and retinal pigment epithelium (RPE). Tspo was induced in the mouse retina upon degeneration, but constitutively expressed in the RPE. Similarly, TSPO expression levels in healthy human retina and RPE were not differentially regulated during aging. Tspo-KO mice had normal retinal morphology and function up to 48 weeks of age. Photoreceptor loss caused either by exposure to excessive light levels or by a mutation in the phosphodiesterase 6b gene was not affected by the absence of Tspo. The reactivity states of retinal mononuclear phagocytes following light-damage were comparable in Tspo-KO and control mice. Our data suggest that lack of endogenous TSPO does not directly influence the magnitude of photoreceptor degeneration or microglia activation in these two models of retinal degeneration. We therefore hypothesize that the interaction of TSPO with its ligands may be required to modulate disease progression.
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Affiliation(s)
- Katrin Klee
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Federica Storti
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Maya Barben
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Marijana Samardzija
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Cologne, Germany
| | - Joshua Dunaief
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Christian Grimm
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland; Neuroscience Center, University of Zurich, Zurich, Switzerland.
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Hyperoxia but not AOX expression mitigates pathological cardiac remodeling in a mouse model of inflammatory cardiomyopathy. Sci Rep 2019; 9:12741. [PMID: 31484989 PMCID: PMC6726756 DOI: 10.1038/s41598-019-49231-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/21/2019] [Indexed: 11/17/2022] Open
Abstract
Constitutive expression of the chemokine Mcp1 in mouse cardiomyocytes creates a model of inflammatory cardiomyopathy, with death from heart failure at age 7–8 months. A critical pathogenic role has previously been proposed for induced oxidative stress, involving NADPH oxidase activation. To test this idea, we exposed the mice to elevated oxygen levels. Against expectation, this prevented, rather than accelerated, the ultrastructural and functional signs of heart failure. This result suggests that the immune signaling initiated by Mcp1 leads instead to the inhibition of cellular oxygen usage, for which mitochondrial respiration is an obvious target. To address this hypothesis, we combined the Mcp1 model with xenotopic expression of the alternative oxidase (AOX), which provides a sink for electrons blocked from passage to oxygen via respiratory complexes III and IV. Ubiquitous AOX expression provided only a minor delay to cardiac functional deterioration and did not prevent the induction of markers of cardiac and metabolic remodeling considered a hallmark of the model. Moreover, cardiomyocyte-specific AOX expression resulted in exacerbation of Mcp1-induced heart failure, and failed to rescue a second cardiomyopathy model directly involving loss of cIV. Our findings imply that mitochondrial involvement in the pathology of inflammatory cardiomyopathy is multifaceted and complex.
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Storm T, Burgoyne T, Dunaief JL, Christensen EI, Futter C, Nielsen R. Selective Ablation of Megalin in the Retinal Pigment Epithelium Results in Megaophthalmos, Macromelanosome Formation and Severe Retina Degeneration. Invest Ophthalmol Vis Sci 2019; 60:322-330. [PMID: 30665232 PMCID: PMC6343679 DOI: 10.1167/iovs.18-25667] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Mutations in the megalin-encoding gene, LRP2, cause high myopia as seen in patients suffering from Donnai-Barrow/facio-oculo-acoustico-renal syndrome. Megalin is present in both the nonpigmented epithelium of the ciliary body and in the RPE. In this study, we set out to establish an animal model to study the mechanisms underlying the ocular phenotype and to establish if high myopia/megaophthalmos is induced by postnatal megalin-deficiency in the RPE. Methods Postnatal RPE-specific deletion of megalin was generated by crossing mice bearing a homozygous loxP-flanked Lrp2 allele with transgenic mice expressing the Cre recombinase driven by the BEST1 promotor. The model was investigated by immunohistologic techniques, and transmission electron microscopy. Results Mice with postnatal RPE-specific loss of megalin developed a megaophthalmos phenotype with dramatic increase in ocular size and severe retinal thinning associated with compromised vision. This phenotype was present at postnatal day 14, indicating rapid development in the period from onset of BEST1 promotor activity at postnatal day 10. Additionally, RPE melanosomes exhibited abnormal size and morphology, suggested by electron tomography to be caused by fusion events between multiple melanosomes. Conclusions Postnatal loss of megalin in the RPE induces dramatic and rapid ocular growth and retinal degeneration compatible with the high myopia observed in Donnai-Barrow patients. The morphologic changes of RPE melanosomes, believed to be largely inert and fully differentiated at birth, suggested a continued plasticity of mature melanosomes and a requirement for megalin to maintain their number and morphology.
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Affiliation(s)
- Tina Storm
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | | | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Erik I Christensen
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Clare Futter
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Rikke Nielsen
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
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Liu Y, Kanda A, Wu D, Ishizuka ET, Kase S, Noda K, Ichihara A, Ishida S. Suppression of Choroidal Neovascularization and Fibrosis by a Novel RNAi Therapeutic Agent against (Pro)renin Receptor. MOLECULAR THERAPY-NUCLEIC ACIDS 2019; 17:113-125. [PMID: 31254924 PMCID: PMC6599885 DOI: 10.1016/j.omtn.2019.05.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 12/17/2022]
Abstract
The receptor-associated prorenin system refers to the pathogenic mechanism whereby prorenin binding to (pro)renin receptor [(P)RR] dually activates the tissue renin-angiotensin system (RAS) and RAS-independent signaling, and its activation contributes to the molecular pathogenesis of various ocular diseases. We recently developed a new single-stranded RNAi agent targeting both human and mouse (P)RR ((P)RR-proline-modified short hairpin RNA [(P)RR-PshRNA]), and confirmed its therapeutic effect on murine models of ocular inflammation. Here, we investigated the efficacy of (P)RR-PshRNA against laser-induced choroidal neovascularization (CNV) and subretinal fibrosis, both of which are involved in the pathogenesis of age-related macular degeneration (AMD). Administration of (P)RR-PshRNA in mice significantly reduced CNV formation, together with the expression of inflammatory molecules, macrophage infiltration, and extracellular signal-regulated kinase (ERK) 1/2 activation. In addition, (P)RR-PshRNA attenuated subretinal fibrosis, together with epithelial-mesenchymal transition (EMT)-related markers including phosphorylated SMAD2. The suppressive effect of (P)RR-PshRNA is comparable with aflibercept, an anti-vascular endothelial growth factor drug widely used for AMD therapy. AMD patient specimens demonstrated (P)RR co-localization with phosphorylated ERK1/2 in neovascular endothelial cells and retinal pigment epithelial cells. These results indicate that (P)RR contributes to the ocular pathogenesis of both inflammation-related angiogenesis and EMT-driven fibrosis, and that (P)RR-PshRNA is a promising therapeutic agent for AMD.
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Affiliation(s)
- Ye Liu
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060-8638, Japan
| | - Atsuhiro Kanda
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060-8638, Japan.
| | - Di Wu
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060-8638, Japan
| | - Erdal Tan Ishizuka
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060-8638, Japan
| | - Satoru Kase
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060-8638, Japan
| | - Kousuke Noda
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060-8638, Japan
| | - Atsuhiro Ichihara
- Department of Endocrinology and Hypertension, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Susumu Ishida
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060-8638, Japan
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Storti F, Klee K, Todorova V, Steiner R, Othman A, van der Velde-Visser S, Samardzija M, Meneau I, Barben M, Karademir D, Pauzuolyte V, Boye SL, Blaser F, Ullmer C, Dunaief JL, Hornemann T, Rohrer L, den Hollander A, von Eckardstein A, Fingerle J, Maugeais C, Grimm C. Impaired ABCA1/ABCG1-mediated lipid efflux in the mouse retinal pigment epithelium (RPE) leads to retinal degeneration. eLife 2019; 8:45100. [PMID: 30864945 PMCID: PMC6435327 DOI: 10.7554/elife.45100] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/12/2019] [Indexed: 01/04/2023] Open
Abstract
Age-related macular degeneration (AMD) is a progressive disease of the retinal pigment epithelium (RPE) and the retina leading to loss of central vision. Polymorphisms in genes involved in lipid metabolism, including the ATP-binding cassette transporter A1 (ABCA1), have been associated with AMD risk. However, the significance of retinal lipid handling for AMD pathogenesis remains elusive. Here, we study the contribution of lipid efflux in the RPE by generating a mouse model lacking ABCA1 and its partner ABCG1 specifically in this layer. Mutant mice show lipid accumulation in the RPE, reduced RPE and retinal function, retinal inflammation and RPE/photoreceptor degeneration. Data from human cell lines indicate that the ABCA1 AMD risk-conferring allele decreases ABCA1 expression, identifying the potential molecular cause that underlies the genetic risk for AMD. Our results highlight the essential homeostatic role for lipid efflux in the RPE and suggest a pathogenic contribution of reduced ABCA1 function to AMD.
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Affiliation(s)
- Federica Storti
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Katrin Klee
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland.,Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Vyara Todorova
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Regula Steiner
- Institute of Clinical Chemistry, University of Zurich, Schlieren, Switzerland
| | - Alaa Othman
- Institute of Clinical Chemistry, University of Zurich, Schlieren, Switzerland
| | | | - Marijana Samardzija
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Isabelle Meneau
- Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland
| | - Maya Barben
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Duygu Karademir
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland.,Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Valda Pauzuolyte
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Sanford L Boye
- Department of Ophthalmology, University of Florida, Gainesville, United States
| | - Frank Blaser
- Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland
| | - Christoph Ullmer
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Joshua L Dunaief
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, United States
| | - Thorsten Hornemann
- Institute of Clinical Chemistry, University of Zurich, Schlieren, Switzerland
| | - Lucia Rohrer
- Institute of Clinical Chemistry, University of Zurich, Schlieren, Switzerland
| | - Anneke den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Jürgen Fingerle
- Natural and Medical Sciences Institute, University of Tübingen, Tübingen, Germany
| | - Cyrille Maugeais
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Christian Grimm
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland.,Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
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Huang J, Gu S, Chen M, Zhang SJ, Jiang Z, Chen X, Jiang C, Liu G, Radu RA, Sun X, Vollrath D, Du J, Yan B, Zhao C. Abnormal mTORC1 signaling leads to retinal pigment epithelium degeneration. Am J Cancer Res 2019; 9:1170-1180. [PMID: 30867823 PMCID: PMC6401408 DOI: 10.7150/thno.26281] [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: 03/25/2018] [Accepted: 12/24/2018] [Indexed: 12/13/2022] Open
Abstract
Retinal pigment epithelial (RPE) degeneration is potentially involved in the pathogenesis of several retinal degenerative diseases. mTORC1 signaling is shown as a crucial regulator of many biological processes and disease progression. In this study, we aimed at investigating the role of mTORC1 signaling in RPE degeneration. Methods: Western blots were conducted to detect mTORC1 expression pattern during RPE degeneration. Cre-loxP system was used to generate RPE-specific mTORC1 activation mice. Fundus, immunofluorescence staining, transmission electron microscopy, and targeted metabolomic analysis were conducted to determine the effects of mTORC1 activation on RPE degeneration in vivo. Electroretinography, spectral-domain optical coherence tomography, and histological experiments were conducted to determine the effects of mTORC1 activation on choroidal and retinal function in vivo. Results: RPE-specific activation of mTORC1 led to RPE degeneration as shown by the loss of RPE-specific marker, compromised cell junction integrity, and intracellular accumulation of lipid droplets. RPE degeneration further led to abnormal choroidal and retinal function. The inhibition of mTORC1 signaling with rapamycin could partially reverse RPE degeneration. Targeted metabolomics analysis further revealed that mTORC1 activation affected the metabolism of purine, carboxylic acid, and niacin in RPE. Conclusion: This study revealed that abnormal activation of mTORC1 signaling leads to RPE degeneration, which could provide a promising target for the treatment of RPE dysfunction-related diseases.
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Tarchick MJ, Cutler AH, Trobenter TD, Kozlowski MR, Makowski ER, Holoman N, Shao J, Shen B, Anand-Apte B, Samuels IS. Endogenous insulin signaling in the RPE contributes to the maintenance of rod photoreceptor function in diabetes. Exp Eye Res 2018; 180:63-74. [PMID: 30543793 DOI: 10.1016/j.exer.2018.11.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 01/01/2023]
Abstract
In diabetes, there are two major physiological aberrations: (i) Loss of insulin signaling due to absence of insulin (type 1 diabetes) or insulin resistance (type 2 diabetes) and (ii) increased blood glucose levels. The retina has a high proclivity to damage following diabetes, and much of the pathology seen in diabetic retinopathy has been ascribed to hyperglycemia and downstream cascades activated by increased blood glucose. However, less attention has been focused on the direct role of insulin on retinal physiology, likely due to the fact that uptake of glucose in retinal cells is not insulin-dependent. The retinal pigment epithelium (RPE) is instrumental in maintaining the structural and functional integrity of the retina. Recent studies have suggested that RPE dysfunction is a precursor of, and contributes to, the development of diabetic retinopathy. To evaluate the role of insulin on RPE cell function directly, we generated a RPE specific insulin receptor (IR) knockout (RPEIRKO) mouse using the Cre-loxP system. Using this mouse, we sought to determine the impact of insulin-mediated signaling in the RPE on retinal function under physiological control conditions as well as in streptozotocin (STZ)-induced diabetes. We demonstrate that loss of RPE-specific IR expression resulted in lower a- and b-wave electroretinogram amplitudes in diabetic mice as compared to diabetic mice that expressed IR on the RPE. Interestingly, RPEIRKO mice did not exhibit significant differences in the amplitude of the RPE-dependent electroretinogram c-wave as compared to diabetic controls. However, loss of IR-mediated signaling in the RPE reduced levels of reactive oxygen species and the expression of pro-inflammatory cytokines in the retina of diabetic mice. These results imply that IR-mediated signaling in the RPE regulates photoreceptor function and may play a role in the generation of oxidative stress and inflammation in the retina in diabetes.
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Affiliation(s)
- Matthew J Tarchick
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA; Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Alecia H Cutler
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Timothy D Trobenter
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA; Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Michael R Kozlowski
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Emily R Makowski
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA; Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Nicholas Holoman
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA; Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Jianning Shao
- Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Bailey Shen
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Bela Anand-Apte
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA; Department of Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Ivy S Samuels
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA; Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
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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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Schneider S, Hotaling N, Campos M, Patnaik SR, Bharti K, May-Simera HL. Generation of an inducible RPE-specific Cre transgenic-mouse line. PLoS One 2018; 13:e0207222. [PMID: 30440011 PMCID: PMC6237357 DOI: 10.1371/journal.pone.0207222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 10/26/2018] [Indexed: 11/19/2022] Open
Abstract
The retinal pigment epithelium (RPE) is an epithelial monolayer in the back of the vertebrate eye. RPE dysfunction is associated with retinal degeneration and blindness. In order to fully understand how dysregulation affects visual function, RPE-specific gene knockouts are indispensable. Since the currently available RPE-specific Cre recombinases show lack of specificity or poor recombination, we sought to generate an alternative. We generated a tamoxifen-inducible RPE-specific Cre transgenic mouse line under transcriptional control of an RPE-specific Tyrosinase enhancer. We characterized the Cre-mediated recombinant expression by crossing our RPE-Tyrosinase-CreErT2 mouse line with the tdTomato reporter line, Ai14. Detected fluorescence was quantified via high-content image analysis. Recombination was predominantly observed in the RPE and adjacent ciliary body. RPE flatmount preparations revealed a high level of recombination in adult mice (47.25-69.48%). Regional analysis of dorsal, ventral, nasal and temporal areas did not show significant changes in recombination. However, recombination was higher in the central RPE compared to the periphery. Higher levels of Cre-mediated recombinant expression was observed in embryonic RPE (~83%). Compared to other RPE-specific Cre transgenic mouse lines, this newly generated RPE-Tyrosinase-CreErT2 line shows a more uniform and higher level of recombination with the advantage to initiate recombination in both, prenatal and postnatal animals. This line can serve as a valuable tool for researches exploring the role of individual gene functions, in both developing and differentiated RPE.
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Affiliation(s)
- Sandra Schneider
- Institute of Molecular Physiology, Johannes-Gutenberg University, Mainz, Germany
| | - Nathan Hotaling
- National Eye Institute, NIH, Bethesda, MD, United States of America
| | - Maria Campos
- National Eye Institute, NIH, Bethesda, MD, United States of America
| | - Sarita Rani Patnaik
- Institute of Molecular Physiology, Johannes-Gutenberg University, Mainz, Germany
| | - Kapil Bharti
- National Eye Institute, NIH, Bethesda, MD, United States of America
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Conditional loss of Kcnj13 in the retinal pigment epithelium causes photoreceptor degeneration. Exp Eye Res 2018; 176:219-226. [PMID: 30009826 DOI: 10.1016/j.exer.2018.07.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/20/2018] [Accepted: 07/11/2018] [Indexed: 12/31/2022]
Abstract
The retina is the light sensing tissue of the eye which contains multiple layers of cells required for the detection and transmission of a visual signal. Loss of the light-sensing photoreceptors leads to defects in visual function and blindness. Previously, we found that mosaic deletion of Kcnj13, and subsequent loss of the potassium channel Kir7.1, in mice leads to photoreceptor degeneration and recapitulates the human retinal disease phenotype (Zhong et al., 2015). Kcnj13 expression in the retinal pigment epithelium (RPE) is essential for normal retinal electrophysiology, function, and survival. Mice with homozygous loss of Kcnj13 die at postnatal day 1 (P1), requiring a tissue-specific approach to study retinal degeneration phenotypes in adult mice. We used the CRISPR-Cas9 system to generate a floxed, conditional loss-of-function (cKO) Kcnj13flox allele to study the pathogenesis of Kcnj13 deficiency in the retina. To investigate if the Kcnj13 is required in the RPE for photoreceptor function and survival, we used Best1-cre, which is specifically expressed in the RPE. We observed complete loss of Kcnj13 expression in Cre-positive RPE cells. Furthermore, our findings show that widespread loss of Kcnj13 in the RPE leads to severe and progressive thinning of the outer nuclear layer and a reduced response to light. Finally, to detect Best1-cre expression in the RPE of live animals without sacrificing the animal for histology, we generated a Cre-reporter-containing Kcnj13 cKO mouse line (cKOR: Kcnj13flox/flox; Best1-cre; Ai9) which can be rapidly screened using retinal fluorescence microscopy. These findings provide new tools for studying the roles of Kcnj13 in retinal homeostasis.
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Eblimit A, Agrawal SA, Thomas K, Anastassov IA, Abulikemu T, Moayedi Y, Mardon G, Chen R. Conditional loss of Spata7 in photoreceptors causes progressive retinal degeneration in mice. Exp Eye Res 2018; 166:120-130. [PMID: 29100828 PMCID: PMC5756513 DOI: 10.1016/j.exer.2017.10.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 10/10/2017] [Accepted: 10/13/2017] [Indexed: 12/31/2022]
Abstract
The mammalian retina consists of multiple cell layers including photoreceptor cells, which are light sensing neurons that play essential functions in the visual process. Previously, we identified mutations in SPATA7, encoding spermatogenesis associated protein 7, in families with Leber Congenital Amaurosis (LCA) and juvenile Retinitis Pigmentosa (RP), and showed that Spata7 null mice recapitulate the human disease phenotype of retinal degeneration. SPATA7 is expressed in the connecting cilium of photoreceptor (PR) cells in the mouse retina, as well as in retinal pigment epithelium (RPE) cells, but the functional role of Spata7 in the RPE remains unknown. To investigate whether Spata7 is required in PRs, the RPE, or both, we conditionally knocked out Spata7 in photoreceptors and RPE cells using Crx-Cre and Best1-Cre transgenic mouse lines, respectively. In Spata7 photoreceptor-specific conditional (cKO) mice, both rod and cone photoreceptor dysfunction and degeneration is observed, characterized by progressive thinning of the outer nuclear layer and reduced response to light; however, RPE-specific deletion of Spata7 does not impair retinal function or cell survival. Furthermore, our findings show that both Rhodopsin and RPGRIP1 are mislocalized in the Spata7Flox/-; Crx-Cre cKO mice, suggesting that loss of Spata7 in photoreceptors alone can result in altered trafficking of these proteins in the connecting cilium. Together, our findings suggest that loss of Spata7 in photoreceptors alone is sufficient to cause photoreceptor degeneration, but its function in the RPE is not required for photoreceptor survival; therefore, loss of Spata7 in photoreceptors alters both rod and cone function and survival, consistent with the clinical phenotypes observed in LCA and RP patients with mutations in SPATA7.
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Affiliation(s)
- Aiden Eblimit
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Smriti Akshay Agrawal
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Kandace Thomas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Ivan Assenov Anastassov
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Tajiguli Abulikemu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA; The Key Laboratory of Plant Resources and Chemistry of Arid Zone, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi, Xinjiang, 830011, China
| | | | - Graeme Mardon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030-3411, USA.
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA.
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Cain-Hom C, Splinter E, van Min M, Simonis M, van de Heijning M, Martinez M, Asghari V, Cox JC, Warming S. Efficient mapping of transgene integration sites and local structural changes in Cre transgenic mice using targeted locus amplification. Nucleic Acids Res 2017; 45:e62. [PMID: 28053125 PMCID: PMC5416772 DOI: 10.1093/nar/gkw1329] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/20/2016] [Indexed: 12/23/2022] Open
Abstract
Cre/LoxP technology is widely used in the field of mouse genetics for spatial and/or temporal regulation of gene function. For Cre lines generated via pronuclear microinjection of a Cre transgene construct, the integration site is random and in most cases not known. Integration of a transgene can disrupt an endogenous gene, potentially interfering with interpretation of the phenotype. In addition, knowledge of where the transgene is integrated is important for planning of crosses between animals carrying a conditional allele and a given Cre allele in case the alleles are on the same chromosome. We have used targeted locus amplification (TLA) to efficiently map the transgene location in seven previously published Cre and CreERT2 transgenic lines. In all lines, transgene insertion was associated with structural changes of variable complexity, illustrating the importance of testing for rearrangements around the integration site. In all seven lines the exact integration site and breakpoint sequences were identified. Our methods, data and genotyping assays can be used as a resource for the mouse community and our results illustrate the power of the TLA method to not only efficiently map the integration site of any transgene, but also provide additional information regarding the transgene integration events.
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Affiliation(s)
- Carol Cain-Hom
- Department of Transgenic Technology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Erik Splinter
- Cergentis BV, Yalelaan 62, 3584 CM Utrecht, the Netherlands
| | - Max van Min
- Cergentis BV, Yalelaan 62, 3584 CM Utrecht, the Netherlands
| | | | | | - Maria Martinez
- Department of Transgenic Technology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Vida Asghari
- Department of Transgenic Technology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - J Colin Cox
- Department of Transgenic Technology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Søren Warming
- Department of Molecular Biology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
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50
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Ma W, Zhang Y, Gao C, Fariss RN, Tam J, Wong WT. Monocyte infiltration and proliferation reestablish myeloid cell homeostasis in the mouse retina following retinal pigment epithelial cell injury. Sci Rep 2017; 7:8433. [PMID: 28814744 PMCID: PMC5559448 DOI: 10.1038/s41598-017-08702-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/13/2017] [Indexed: 02/07/2023] Open
Abstract
Age-related macular degeneration (AMD), a leading contributor of vision loss, currently lacks comprehensive treatment. While AMD histopathology involves retinal pigment epithelium (RPE) injury associated with immune cell infiltration, the nature of immune cell responses to RPE injury remains undefined. We induced RPE injury pharmacologically and genetically in transgenic mouse models in which microglia and systemic monocytes were separately tagged, enabling a spatial and temporal dissection of the relative contributions of microglia vs. monocytes to post-injury changes. We found that myeloid cell responses to RPE injury occur in stages: (1) an early mobilization of endogenous microglia from the inner retina to the RPE layer, followed by (2) subsequent monocyte infiltration from the retinal vasculature into the inner retina that replenishes the local myeloid cell population in a CCR2-regulated manner. These altered distributions of myeloid cells post-injury were long-lived, with recruited monocytes acquiring the distribution, markers, and morphologies of neighboring endogenous microglia in a durable manner. These findings indicate the role played by infiltrating monocytes in maintaining myeloid cell homeostasis in the retina following AMD-relevant RPE injury and provide a foundation for understanding and therapeutically modulating immune aspects in retinal disease.
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Affiliation(s)
- Wenxin Ma
- Unit on Neuron-Glia Interactions in Retinal Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yikui Zhang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Chun Gao
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Robert N Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Johnny Tam
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Institutes of Health, Bethesda, MD, 20892, USA.
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