1
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Motipally SI, Kolson DR, Guan T, Kolandaivelu S. Aberrant lipid accumulation and retinal pigment epithelium dysfunction in PRCD-deficient mice. Exp Eye Res 2024; 246:110016. [PMID: 39098587 PMCID: PMC11388538 DOI: 10.1016/j.exer.2024.110016] [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: 05/30/2024] [Revised: 07/24/2024] [Accepted: 07/30/2024] [Indexed: 08/06/2024]
Abstract
Progressive Rod-Cone Degeneration (PRCD) is an integral membrane protein found in photoreceptor outer segment (OS) disc membranes and its function remains unknown. Mutations in Prcd are implicated in Retinitis pigmentosa (RP) in humans and multiple dog breeds. PRCD-deficient models exhibit decreased levels of cholesterol in the plasma. However, potential changes in the retinal cholesterol remain unexplored. In addition, impaired phagocytosis observed in these animal models points to potential deficits in the retinal pigment epithelium (RPE). Here, using a Prcd-/- murine model we investigated the alterations in the retinal cholesterol levels and impairments in the structural and functional integrity of the RPE. Lipidomic and immunohistochemical analyses show a 5-fold increase in the levels of cholesteryl esters (C.Es) and lipid deposits in the PRCD-deficient retina, respectively, indicating alterations in total retinal cholesterol. Furthermore, the RPE of Prcd-/- mice exhibit a 1.7-fold increase in the expression of lipid transporter gene ATP-binding cassette transporter A1 (Abca1). Longitudinal fundus and spectral domain optical coherence tomography (SD-OCT) examinations showed focal lesions and RPE hyperreflectivity. Strikingly, the RPE of Prcd-/- mice exhibited age-related pathological features such as lipofuscin accumulation, Bruch's membrane (BrM) deposits and drusenoid focal deposits, mirroring an Age-related Macular Degeneration (AMD)-like phenotype. We propose that the extensive lipofuscin accumulation likely impairs lysosomal function, leading to the defective phagocytosis observed in Prcd-/- mice. Our findings support the dysregulation of retinal cholesterol homeostasis in the absence of PRCD. Further, we demonstrate that progressive photoreceptor degeneration in Prcd-/- mice is accompanied by progressive structural and functional deficits in the RPE, which likely exacerbates vision loss over time.
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Affiliation(s)
- Sree I Motipally
- Department of Neuroscience, Rockefeller Neuroscience Institute, 33 Medical Centre Drive, West Virginia University, Morgantown, WV, 26506, USA; Department of Ophthalmology and Visual Sciences, One Medical Center Drive, ERMA 2nd Floor, West Virginia University, Morgantown, WV, 26505-9193, USA
| | - Douglas R Kolson
- Department of Ophthalmology and Visual Sciences, One Medical Center Drive, ERMA 2nd Floor, West Virginia University, Morgantown, WV, 26505-9193, USA
| | - Tongju Guan
- Department of Ophthalmology and Visual Sciences, One Medical Center Drive, ERMA 2nd Floor, West Virginia University, Morgantown, WV, 26505-9193, USA; Department of Biochemistry and Molecular Medicine, 64 Medical Center Drive, West Virginia University, Morgantown, WV, 26505-9193, USA
| | - Saravanan Kolandaivelu
- Department of Ophthalmology and Visual Sciences, One Medical Center Drive, ERMA 2nd Floor, West Virginia University, Morgantown, WV, 26505-9193, USA; Department of Biochemistry and Molecular Medicine, 64 Medical Center Drive, West Virginia University, Morgantown, WV, 26505-9193, USA.
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2
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Lewis TR, Castillo CM, Klementieva NV, Hsu Y, Hao Y, Spencer WJ, Drack AV, Pazour GJ, Arshavsky VY. Contribution of intraflagellar transport to compartmentalization and maintenance of the photoreceptor cell. Proc Natl Acad Sci U S A 2024; 121:e2408551121. [PMID: 39145934 PMCID: PMC11348033 DOI: 10.1073/pnas.2408551121] [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: 04/29/2024] [Accepted: 07/15/2024] [Indexed: 08/16/2024] Open
Abstract
The first steps of vision take place in the ciliary outer segment compartment of photoreceptor cells. The protein composition of outer segments is uniquely suited to perform this function. The most abundant among these proteins is the visual pigment, rhodopsin, whose outer segment trafficking involves intraflagellar transport (IFT). Here, we report three major findings from the analysis of mice in which ciliary transport was acutely impaired by conditional knockouts of IFT-B subunits. First, we demonstrate the existence of a sorting mechanism whereby mislocalized rhodopsin is recruited to and concentrated in extracellular vesicles prior to their release, presumably to protect the cell from adverse effects of protein mislocalization. Second, reducing rhodopsin expression significantly delays photoreceptor degeneration caused by IFT disruption, suggesting that controlling rhodopsin levels may be an effective therapy for some cases of retinal degenerative disease. Last, the loss of IFT-B subunits does not recapitulate a phenotype observed in mutants of the BBSome (another ciliary transport protein complex relying on IFT) in which non-ciliary proteins accumulate in the outer segment. Whereas it is widely thought that the role of the BBSome is to primarily participate in ciliary transport, our data suggest that the BBSome has another major function independent of IFT and possibly related to maintaining the diffusion barrier of the ciliary transition zone.
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Affiliation(s)
- Tylor R. Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | - Carson M. Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | | | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA52242
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | - William J. Spencer
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | - Arlene V. Drack
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA52242
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA01605
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC27710
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3
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Xu J, Zhao C, Kang Y. The Formation and Renewal of Photoreceptor Outer Segments. Cells 2024; 13:1357. [PMID: 39195247 DOI: 10.3390/cells13161357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 08/12/2024] [Accepted: 08/13/2024] [Indexed: 08/29/2024] Open
Abstract
The visual system is essential for humans to perceive the environment. In the retina, rod and cone photoreceptor neurons are the initial sites where vision forms. The apical region of both cone and rod photoreceptors contains a light-sensing organelle known as the outer segment (OS), which houses tens of thousands of light-sensitive opsins. The OSs of photoreceptors are not static; they require rhythmic renewal to maintain normal physiological functions. Disruptions in OS renewal can lead to various genetic disorders, such as retinitis pigmentosa (RP). Understanding the patterns and molecular mechanisms of photoreceptor OS renewal remains one of the most intriguing topics in visual biology. This review aims to elucidate the structure of photoreceptor OSs, the molecular mechanisms underlying photoreceptor OS renewal, and the retinal diseases resulting from defects in this renewal process. Additionally, we will explore retinal diseases related to photoreceptor OS renewal and potential therapeutic strategies, concluding with a discussion on future research directions for OS renewal.
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Affiliation(s)
- Jingjin Xu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Chengtian Zhao
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Yunsi Kang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
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4
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Chen Y, Li E, Chang Z, Zhang T, Song Z, Wu H, Cheng ZJ, Sun B. Identifying potential therapeutic targets in lung adenocarcinoma: a multi-omics approach integrating bulk and single-cell RNA sequencing with Mendelian randomization. Front Pharmacol 2024; 15:1433147. [PMID: 39092217 PMCID: PMC11291359 DOI: 10.3389/fphar.2024.1433147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 06/25/2024] [Indexed: 08/04/2024] Open
Abstract
Our research aimed to identify new therapeutic targets for Lung adenocarcinoma (LUAD), a major subtype of non-small cell lung cancer known for its low 5-year survival rate of 22%. By employing a comprehensive methodological approach, we analyzed bulk RNA sequencing data from 513 LUAD and 59 non-tumorous tissues, identifying 2,688 differentially expressed genes. Using Mendelian randomization (MR), we identified 74 genes with strong evidence for a causal effect on risk of LUAD. Survival analysis on these genes revealed significant differences in survival rates for 13 of them. Our pathway enrichment analysis highlighted their roles in immune response and cell communication, deepening our understanding. We also utilized single-cell RNA sequencing (scRNA-seq) to uncover cell type-specific gene expression patterns within LUAD, emphasizing the tumor microenvironment's heterogeneity. Pseudotime analysis further assisted in assessing the heterogeneity of tumor cell populations. Additionally, protein-protein interaction (PPI) network analysis was conducted to evaluate the potential druggability of these identified genes. The culmination of our efforts led to the identification of five genes (tier 1) with the most compelling evidence, including SECISBP2L, PRCD, SMAD9, C2orf91, and HSD17B13, and eight genes (tier 2) with convincing evidence for their potential as therapeutic targets.
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Affiliation(s)
- Youpeng Chen
- Department of Clinical Laboratory, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Enzhong Li
- Department of Endocrinology, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zhenglin Chang
- Department of Clinical Laboratory, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Tingting Zhang
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zhenfeng Song
- Department of Clinical Laboratory, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Haojie Wu
- Department of Clinical Laboratory, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Zhangkai J. Cheng
- Department of Clinical Laboratory, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Baoqing Sun
- Department of Clinical Laboratory, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
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5
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Hanke-Gogokhia C, Zapadka TE, Finkelstein S, Klingeborn M, Maugel TK, Singer JH, Arshavsky VY, Demb JB. The Structural and Functional Integrity of Rod Photoreceptor Ribbon Synapses Depends on Redundant Actions of Dynamins 1 and 3. J Neurosci 2024; 44:e1379232024. [PMID: 38641407 PMCID: PMC11209669 DOI: 10.1523/jneurosci.1379-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 04/02/2024] [Accepted: 04/13/2024] [Indexed: 04/21/2024] Open
Abstract
Vertebrate vision begins with light absorption by rod and cone photoreceptors, which transmit signals from their synaptic terminals to second-order neurons: bipolar and horizontal cells. In mouse rods, there is a single presynaptic ribbon-type active zone at which the release of glutamate occurs tonically in the dark. This tonic glutamatergic signaling requires continuous exo- and endocytosis of synaptic vesicles. At conventional synapses, endocytosis commonly requires dynamins: GTPases encoded by three genes (Dnm1-3), which perform membrane scission. Disrupting endocytosis by dynamin deletions impairs transmission at conventional synapses, but the impact of disrupting endocytosis and the role(s) of specific dynamin isoforms at rod ribbon synapses are understood incompletely. Here, we used cell-specific knock-outs (KOs) of the neuron-specific Dnm1 and Dnm3 to investigate the functional roles of dynamin isoforms in rod photoreceptors in mice of either sex. Analysis of synaptic protein expression, synapse ultrastructure, and retinal function via electroretinograms (ERGs) showed that dynamins 1 and 3 act redundantly and are essential for supporting the structural and functional integrity of rod ribbon synapses. Single Dnm3 KO showed no phenotype, and single Dnm1 KO only modestly reduced synaptic vesicle density without affecting vesicle size and overall synapse integrity, whereas double Dnm1/Dnm3 KO impaired vesicle endocytosis profoundly, causing enlarged vesicles, reduced vesicle density, reduced ERG responses, synaptic terminal degeneration, and disassembly and degeneration of postsynaptic processes. Concurrently, cone function remained intact. These results show the fundamental redundancy of dynamins 1 and 3 in regulating the structure and function of rod ribbon synapses.
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Affiliation(s)
- Christin Hanke-Gogokhia
- Departments of Ophthalmology & Visual Science, Yale University, New Haven, Connecticut 06511
| | - Thomas E Zapadka
- Departments of Ophthalmology & Visual Science, Yale University, New Haven, Connecticut 06511
- Cellular & Molecular Physiology, Yale University, New Haven, Connecticut 06511
| | - Stella Finkelstein
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27705
| | - Mikael Klingeborn
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27705
| | - Timothy K Maugel
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | - Joshua H Singer
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27705
| | - Jonathan B Demb
- Departments of Ophthalmology & Visual Science, Yale University, New Haven, Connecticut 06511
- Cellular & Molecular Physiology, Yale University, New Haven, Connecticut 06511
- Department of Neuroscience, Yale University, New Haven, Connecticut 06511
- Wu Tsai Institute, Yale University, New Haven, Connecticut 06511
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6
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Megaw R, Moye A, Zhang Z, Newton F, McPhie F, Murphy LC, McKie L, He F, Jungnickel MK, von Kriegsheim A, Tennant PA, Brotherton C, Gurniak C, Gross AK, Machesky LM, Wensel TG, Mill P. Ciliary tip actin dynamics regulate photoreceptor outer segment integrity. Nat Commun 2024; 15:4316. [PMID: 38773095 PMCID: PMC11109262 DOI: 10.1038/s41467-024-48639-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 05/09/2024] [Indexed: 05/23/2024] Open
Abstract
As signalling organelles, cilia regulate their G protein-coupled receptor content by ectocytosis, a process requiring localised actin dynamics to alter membrane shape. Photoreceptor outer segments comprise an expanse of folded membranes (discs) at the tip of highly-specialised connecting cilia, into which photosensitive GPCRs are concentrated. Discs are shed and remade daily. Defects in this process, due to mutations, cause retinitis pigmentosa (RP). Whilst fundamental for vision, the mechanism of photoreceptor disc generation is poorly understood. Here, we show membrane deformation required for disc genesis is driven by dynamic actin changes in a process akin to ectocytosis. We show RPGR, a leading RP gene, regulates actin-binding protein activity central to this process. Actin dynamics, required for disc formation, are perturbed in Rpgr mouse models, leading to aborted membrane shedding as ectosome-like vesicles, photoreceptor death and visual loss. Actin manipulation partially rescues this, suggesting the pathway could be targeted therapeutically. These findings help define how actin-mediated dynamics control outer segment turnover.
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Affiliation(s)
- Roly Megaw
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK.
- Princess Alexandra Eye Pavilion, NHS Lothian, Edinburgh, EH3 9HA, UK.
| | - Abigail Moye
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhixian Zhang
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Fay Newton
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Fraser McPhie
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Laura C Murphy
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Lisa McKie
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Melissa K Jungnickel
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Alex von Kriegsheim
- Edinburgh Cancer Research United Kingdom Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Peter A Tennant
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Chloe Brotherton
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - Christine Gurniak
- Institute fur Genetik, Universitat Bonn, Karlrobert-Kreiten-Strasse, 53115, Bonn, Germany
| | - Alecia K Gross
- University of Alabama at Birmingham, 2nd Ave South, Birmingham, AL, 35294, USA
| | - Laura M Machesky
- CRUK Scotland Institute, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
- Department of Biochemistry, University of Cambridge, Cambridge, CB1 7UY, UK
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Pleasantine Mill
- MRC Human Genetics Unit, MRC Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
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7
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Motipally SI, Kolson DR, Guan T, Kolandaivelu S. Aberrant lipid accumulation and retinal pigmental epithelium dysfunction in PRCD-deficient mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.08.584131. [PMID: 38558979 PMCID: PMC10979840 DOI: 10.1101/2024.03.08.584131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Progressive Rod-Cone Degeneration (PRCD) is an integral membrane protein found in photoreceptor outer segment (OS) disc membranes and its function remains unknown. Mutations in Prcd are implicated in Retinitis pigmentosa (RP) in humans and multiple dog breeds. PRCD-deficient models exhibit decreased levels of cholesterol in the plasma. However, potential changes in the retinal cholesterol remain unexplored. In addition, impaired phagocytosis observed in these animal models points to potential deficits in the retinal pigment epithelium (RPE). Here, using a Prcd -/- murine model we investigated the alterations in the retinal cholesterol levels and impairments in the structural and functional integrity of the RPE. Lipidomic and immunohistochemical analyses show a 5-fold increase in the levels of cholesteryl esters (C.Es) and accumulation of neutral lipids in the PRCD-deficient retina, respectively, indicating alterations in total retinal cholesterol. Longitudinal fundus and spectral domain optical coherence tomography (SD-OCT) examinations showed focal lesions and RPE hyperreflectivity. Strikingly, the RPE of Prcd -/- mice exhibited age-related pathological features such as neutral lipid deposits, lipofuscin accumulation, Bruch's membrane (BrM) thickening and drusenoid focal deposits, mirroring an Age-related Macular Degeneration (AMD)-like phenotype. We propose that the extensive lipofuscin accumulation likely impairs lysosomal function, leading to the defective phagocytosis observed in Prcd -/- mice. Our findings support the dysregulation of retinal cholesterol homeostasis in the absence of PRCD. Further, we demonstrate that progressive photoreceptor degeneration in Prcd -/- mice is accompanied by progressive structural and functional deficits in the RPE, which likely exacerbates vision loss over time.
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8
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Garner MA, Hubbard MG, Boitet ER, Hubbard ST, Gade A, Ying G, Jones BW, Baehr W, Gross AK. NUDC is critical for rod photoreceptor function, maintenance, and survival. FASEB J 2024; 38:e23518. [PMID: 38441532 PMCID: PMC10917122 DOI: 10.1096/fj.202301641rr] [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: 08/11/2023] [Revised: 01/31/2024] [Accepted: 02/14/2024] [Indexed: 03/07/2024]
Abstract
NUDC (nuclear distribution protein C) is a mitotic protein involved in nuclear migration and cytokinesis across species. Considered a cytoplasmic dynein (henceforth dynein) cofactor, NUDC was shown to associate with the dynein motor complex during neuronal migration. NUDC is also expressed in postmitotic vertebrate rod photoreceptors where its function is unknown. Here, we examined the role of NUDC in postmitotic rod photoreceptors by studying the consequences of a conditional NUDC knockout in mouse rods (rNudC-/- ). Loss of NUDC in rods led to complete photoreceptor cell death at 6 weeks of age. By 3 weeks of age, rNudC-/- function was diminished, and rhodopsin and mitochondria were mislocalized, consistent with dynein inhibition. Levels of outer segment proteins were reduced, but LIS1 (lissencephaly protein 1), a well-characterized dynein cofactor, was unaffected. Transmission electron microscopy revealed ultrastructural defects within the rods of rNudC-/- by 3 weeks of age. We investigated whether NUDC interacts with the actin modulator cofilin 1 (CFL1) and found that in rods, CFL1 is localized in close proximity to NUDC. In addition to its potential role in dynein trafficking within rods, loss of NUDC also resulted in increased levels of phosphorylated CFL1 (pCFL1), which would purportedly prevent depolymerization of actin. The absence of NUDC also induced an inflammatory response in Müller glia and microglia across the neural retina by 3 weeks of age. Taken together, our data illustrate the critical role of NUDC in actin cytoskeletal maintenance and dynein-mediated protein trafficking in a postmitotic rod photoreceptor.
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Affiliation(s)
- Mary Anne Garner
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, 35294 USA
| | - Meredith G. Hubbard
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, 35294 USA
| | - Evan R. Boitet
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, 35294 USA
| | - Seth T. Hubbard
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, 35294 USA
| | - Anushree Gade
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, 35294 USA
| | - Guoxin Ying
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, 84132 USA
| | - Bryan W. Jones
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, 84132 USA
| | - Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, 84132 USA
| | - Alecia K. Gross
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, 35294 USA
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9
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Zhao Q, Lai K. Role of immune inflammation regulated by macrophage in the pathogenesis of age-related macular degeneration. Exp Eye Res 2024; 239:109770. [PMID: 38145794 DOI: 10.1016/j.exer.2023.109770] [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: 09/14/2023] [Revised: 12/05/2023] [Accepted: 12/20/2023] [Indexed: 12/27/2023]
Abstract
Age-related macular degeneration (AMD) can lead to irreversible impairment of visual function, and the number of patients with AMD has been increasing globally. The immunoinflammatory theory is an important pathogenic mechanism of AMD, with macrophages serving as the primary inflammatory infiltrating cells in AMD lesions. Its powerful immunoinflammatory regulatory function has attracted considerable attention. Herein, we provide an overview of the involvement of macrophage-regulated immunoinflammation in different stages of AMD. Additionally, we summarize novel therapeutic approaches for AMD, focusing on targeting macrophages, such as macrophage/microglia modulators, reduction of macrophage aggregation in the subretinal space, modulation of macrophage effector function, macrophage phenotypic alterations, and novel biomimetic nanocomposites development based on macrophage-associated functional properties. We aimed to provide a basis and reference for the further exploration of AMD pathogenesis, developmental influences, and new therapeutic approaches.
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Affiliation(s)
- Qin Zhao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, No.7 Jinsui Road, Guangzhou, 510060, China
| | - Kunbei Lai
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, No.7 Jinsui Road, Guangzhou, 510060, China.
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10
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Garner MA, Hubbard MG, Boitet ER, Hubbard ST, Gade A, Ying G, Jones BW, Baehr W, Gross AK. NUDC is critical for rod photoreceptor function, maintenance, and survival. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.568878. [PMID: 38076848 PMCID: PMC10705250 DOI: 10.1101/2023.11.28.568878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
NUDC ( nu clear d istribution protein C) is a mitotic protein involved in nuclear migration and cytokinesis across species. Considered a cytoplasmic dynein (henceforth dynein) cofactor, NUDC was shown to associate with the dynein motor complex during neuronal migration. NUDC is also expressed in postmitotic vertebrate rod photoreceptors where its function is unknown. Here, we examined the role of NUDC in postmitotic rod photoreceptors by studying the consequences of a conditional NUDC knockout in mouse rods (r NudC -/- ). Loss of NUDC in rods led to complete photoreceptor cell death at six weeks of age. By 3 weeks of age, r NudC -/- function was diminished, and rhodopsin and mitochondria were mislocalized, consistent with dynein inhibition. Levels of outer segment proteins were reduced, but LIS1 (lissencephaly protein 1), a well-characterized dynein cofactor, was unaffected. Transmission electron microscopy revealed ultrastructural defects within the rods of r NudC -/- by 3 weeks of age. We investigated whether NUDC interacts with the actin modulator cofilin 1 (CFL1) and found that in rods, CFL1 is localized in close proximity to NUDC. In addition to its potential role in dynein trafficking within rods, loss of NUDC also resulted in increased levels of phosphorylated CFL1 (pCFL1), which would purportedly prevent depolymerization of actin. Absence of NUDC also induced an inflammatory response in Müller glia and microglia across the neural retina by 3 weeks of age. Taken together, our data illustrate the critical role of NUDC in actin cytoskeletal maintenance and dynein-mediated protein trafficking in a postmitotic rod photoreceptor. Significance Statement Nuclear distribution protein C (NUDC) has been studied extensively as an essential protein for mitotic cell division. In this study, we discovered its expression and role in the postmitotic rod photoreceptor cell. In the absence of NUDC in mouse rods, we detected functional loss, protein mislocalization, and rapid retinal degeneration consistent with dynein inactivation. In the early phase of retinal degeneration, we observed ultrastructural defects and an upregulation of inflammatory markers suggesting additional, dynein-independent functions of NUDC.
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11
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Clark JA, Anderson H, Donner J, Pearce-Kelling S, Ekenstedt KJ. Global Frequency Analyses of Canine Progressive Rod-Cone Degeneration-Progressive Retinal Atrophy and Collie Eye Anomaly Using Commercial Genetic Testing Data. Genes (Basel) 2023; 14:2093. [PMID: 38003037 PMCID: PMC10671078 DOI: 10.3390/genes14112093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Hundreds of genetic variants associated with canine traits and disorders have been identified, with commercial tests offered. However, the geographic distributions and changes in allele and genotype frequencies over prolonged, continuous periods of time are lacking. This study utilized a large set of genotypes from dogs tested for the progressive rod-cone degeneration-progressive retinal atrophy (prcd-PRA) G>A missense PRCD variant (n = 86,667) and the collie eye anomaly (CEA)-associated NHEJ1 deletion (n = 33,834) provided by the commercial genetic testing company (Optigen/Wisdom Panel, Mars Petcare Science & Diagnostics). These data were analyzed using the chi-square goodness-of-fit test, time-trend graphical analysis, and regression modeling in order to evaluate how test results changed over time. The results span fifteen years, representing 82 countries and 67 breeds/breed mixes. Both diseases exhibited significant differences in genotype frequencies (p = 2.7 × 10-152 for prcd-PRA and 0.023 for CEA) with opposing graphical trends. Regression modeling showed time progression to significantly affect the odds of a dog being homozygous or heterozygous for either disease, as do variables including breed and breed popularity. This study shows that genetic testing informed breeding decisions to produce fewer affected dogs. However, the presence of dogs homozygous for the disease variant, especially for prcd-PRA, was still observed fourteen years after test availability, potentially due to crosses of unknown carriers. This suggests that genetic testing of dog populations should continue.
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Affiliation(s)
- Jessica A. Clark
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA;
| | - Heidi Anderson
- Wisdom Panel, Mars Petcare Science & Diagnostics, 00581 Helsinki, Finland; (H.A.); (J.D.)
| | - Jonas Donner
- Wisdom Panel, Mars Petcare Science & Diagnostics, 00581 Helsinki, Finland; (H.A.); (J.D.)
| | | | - Kari J. Ekenstedt
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA;
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12
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Senapati S, Park PSH. Understanding the Rhodopsin Worldview Through Atomic Force Microscopy (AFM): Structure, Stability, and Activity Studies. CHEM REC 2023; 23:e202300113. [PMID: 37265335 PMCID: PMC10908267 DOI: 10.1002/tcr.202300113] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/12/2023] [Indexed: 06/03/2023]
Abstract
Rhodopsin is a G protein-coupled receptor (GPCR) present in the rod outer segment (ROS) of photoreceptor cells that initiates the phototransduction cascade required for scotopic vision. Due to the remarkable advancements in technological tools, the chemistry of rhodopsin has begun to unravel especially over the past few decades, but mostly at the ensemble scale. Atomic force microscopy (AFM) is a tool capable of providing critical information from a single-molecule point of view. In this regard, to bolster our understanding of rhodopsin at the nanoscale level, AFM-based imaging, force spectroscopy, and nano-indentation techniques were employed on ROS disc membranes containing rhodopsin, isolated from vertebrate species both in normal and diseased states. These AFM studies on samples from native retinal tissue have provided fundamental insights into the structure and function of rhodopsin under normal and dysfunctional states. We review here the findings from these AFM studies that provide important insights on the supramolecular organization of rhodopsin within the membrane and factors that contribute to this organization, the molecular interactions stabilizing the structure of the receptor and factors that can modify those interactions, and the mechanism underlying constitutive activity in the receptor that can cause disease.
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Affiliation(s)
- Subhadip Senapati
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
- Prayoga Institute of Education Research, Bengaluru, KA 560116, India
| | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
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13
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Truong HM, Cruz-Colón KO, Martínez-Márquez JY, Willer JR, Travis AM, Biswas SK, Lo WK, Bolz HJ, Pearring JN. The tectonic complex regulates membrane protein composition in the photoreceptor cilium. Nat Commun 2023; 14:5671. [PMID: 37704658 PMCID: PMC10500017 DOI: 10.1038/s41467-023-41450-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 08/30/2023] [Indexed: 09/15/2023] Open
Abstract
The primary cilium is a signaling organelle with a unique membrane composition maintained by a diffusional barrier residing at the transition zone. Many transition zone proteins, such as the tectonic complex, are linked to preserving ciliary composition but the mechanism remains unknown. To understand tectonic's role, we generate a photoreceptor-specific Tctn1 knockout mouse. Loss of Tctn1 results in the absence of the entire tectonic complex and associated MKS proteins yet has minimal effects on the transition zone structure of rod photoreceptors. We find that the protein composition of the photoreceptor cilium is disrupted as non-resident membrane proteins accumulate in the cilium over time, ultimately resulting in photoreceptor degeneration. We further show that fluorescent rhodopsin moves faster through the transition zone in photoreceptors lacking tectonic, which suggests that the tectonic complex acts as a physical barrier to slow down membrane protein diffusion in the photoreceptor transition zone to ensure proper removal of non-resident membrane proteins.
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Affiliation(s)
- Hanh M Truong
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | - Kevin O Cruz-Colón
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | | | - Jason R Willer
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA
| | - Amanda M Travis
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA
| | - Sondip K Biswas
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Woo-Kuen Lo
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Hanno J Bolz
- Senckenberg Centre for Human Genetics, Frankfurt am Main, Germany
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Jillian N Pearring
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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14
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Spencer WJ. Extracellular vesicles highlight many cases of photoreceptor degeneration. Front Mol Neurosci 2023; 16:1182573. [PMID: 37273908 PMCID: PMC10233141 DOI: 10.3389/fnmol.2023.1182573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023] Open
Abstract
The release of extracellular vesicles is observed across numerous cell types and serves a range of biological functions including intercellular communication and waste disposal. One cell type which stands out for its robust capacity to release extracellular vesicles is the vertebrate photoreceptor cell. For decades, the release of extracellular vesicles by photoreceptors has been documented in many different animal models of photoreceptor degeneration and, more recently, in wild type photoreceptors. Here, I review all studies describing extracellular vesicle release by photoreceptors and discuss the most unifying theme among them-a photoreceptor cell fully, or partially, diverts its light sensitive membrane material to extracellular vesicles when it has defects in the delivery or morphing of this material into the photoreceptor's highly organized light sensing organelle. Because photoreceptors generate an enormous amount of light sensitive membrane every day, the diversion of this material to extracellular vesicles can cause a massive accumulation of these membranes within the retina. Little is known about the uptake of photoreceptor derived extracellular vesicles, although in some cases the retinal pigment epithelial cells, microglia, Müller glia, and/or photoreceptor cells themselves have been shown to phagocytize them.
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15
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Bernardo-Colón A, Dong L, Abu-Asab M, Brush RS, Agbaga MP, Becerra SP. Ablation of pigment epithelium-derived factor receptor (PEDF-R/Pnpla2) causes photoreceptor degeneration. J Lipid Res 2023; 64:100358. [PMID: 36934843 PMCID: PMC10233210 DOI: 10.1016/j.jlr.2023.100358] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/03/2023] [Accepted: 03/04/2023] [Indexed: 03/19/2023] Open
Abstract
Photoreceptor cells express the patatin-like phospholipase domain-containing 2 (PNPLA2) gene that codes for pigment epithelium-derived factor receptor (PEDF-R) (also known as ATGL). PEDF-R exhibits phospholipase activity that mediates the neurotrophic action of its ligand PEDF. Because phospholipids are the most abundant lipid class in the retina, we investigated the role of PEDF-R in photoreceptors by generating CRISPR Pnpla2 knock-out mouse lines in a retinal degeneration-free background. Pnpla2-/- mice had undetectable retinal Pnpla2 gene expression and PEDF-R protein levels as assayed by RT-PCR and immunofluorescence, respectively. The photoreceptors of mice deficient in PEDF-R had deformities as examined by histology and transmission electron microscopy. Pnpla2 knockdown diminished the PLA2 enzymatic activity of PEDF-R in the retina. Lipidomic analyses revealed the accumulation of lysophosphatidyl choline-DHA and lysophosphatidyl ethanolamine-DHA in PEDF-R-deficient retinas, suggesting a possible causal link to photoreceptor dysfunction. Loss of PEDF-R decreased levels of rhodopsin, opsin, PKCα, and synaptophysin relative to controls. Pnpla2-/- photoreceptors had surface-exposed phosphatidylserine, and their nuclei were TUNEL positive and condensed, revealing an apoptotic onset. Paralleling its structural defects, PEDF-R deficiency compromised photoreceptor function in vivo as indicated by the attenuation of photoreceptor a- and b-waves in Pnpla2-/- and Pnpla2+/- mice relative to controls as determined by electroretinography. In conclusion, ablation of PEDF-R in mice caused alteration in phospholipid composition associated with malformation and malperformance of photoreceptors. These findings identify PEDF-R as an important component for photoreceptor structure and function, highlighting its role in phospholipid metabolism for retinal survival and its consequences.
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Affiliation(s)
- Alexandra Bernardo-Colón
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mones Abu-Asab
- Histopathology Core Facility, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Richard S Brush
- Department of Ophthalmology(,) and Dean A. McGee Eye Institute, Oklahoma City, OK, USA
| | - Martin-Paul Agbaga
- Department of Ophthalmology(,) and Dean A. McGee Eye Institute, Oklahoma City, OK, USA; Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - S Patricia Becerra
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
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16
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Arthur P, Kandoi S, Sun L, Kalvala A, Kutlehria S, Bhattacharya S, Kulkarni T, Nimma R, Li Y, Lamba DA, Singh M. Biophysical, Molecular and Proteomic Profiling of Human Retinal Organoid-Derived Exosomes. Pharm Res 2023; 40:801-816. [PMID: 36002615 PMCID: PMC10576571 DOI: 10.1007/s11095-022-03350-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/23/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE There is a growing interest in extracellular vesicles (EVs) for ocular applications as therapeutics, biomarkers, and drug delivery vehicles. EVs secreted from mesenchymal stem cells (MSCs) have shown to provide therapeutic benefits in ocular conditions. However, very little is known about the properties of bioreactor cultured-3D human retinal organoids secreted EVs. This study provides a comprehensive morphological, nanomechanical, molecular, and proteomic characterization of retinal organoid EVs and compares it with human umbilical cord (hUC) MSCs. METHODS The morphology and nanomechanical properties of retinal organoid EVs were assessed using Nanoparticle tracking analysis (NTA) and Atomic force microscopy (AFM). Gene expression analysis of exosome biogenesis of early and late retinal organoids were compared using qPCR. The protein profile of the EVs were analyzed with proteomic tools. RESULTS NTA indicated the average size of EV as 100-250 nm. A high expression of exosome biogenesis genes was observed in late retinal organoids EVs. Immunoblot analysis showed highly expressed exosomal markers in late retinal organoids EVs compared to early retinal organoids EVs. Protein profiling of retinal organoid EVs displayed a higher differential expression of retinal function-related proteins and EV biogenesis proteins than hUCMSC EVs, implicating that the use of retinal organoid EVs may have a superior therapeutic effect on retinal disorders. CONCLUSION This study provides supplementary knowledge on the properties of retinal organoid EVs and suggests their potential use in the diagnostic and therapeutic treatments for ocular diseases.
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Affiliation(s)
- Peggy Arthur
- College of Pharmacy and Pharmacological Sciences, Florida A&M University, Tallahassee, FL, USA
| | - Sangeetha Kandoi
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, USA
| | - Li Sun
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, USA
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Anil Kalvala
- College of Pharmacy and Pharmacological Sciences, Florida A&M University, Tallahassee, FL, USA
| | - Shallu Kutlehria
- College of Pharmacy and Pharmacological Sciences, Florida A&M University, Tallahassee, FL, USA
| | - Santanu Bhattacharya
- Department of Biochemistry and Molecular Biology, Mayo College of Medicine and Science, Jacksonville, FL, USA
- Department of Physiology and Biomedical Engineering, Mayo College of Medicine and Science, Jacksonville, FL, USA
| | - Tanmay Kulkarni
- Department of Biochemistry and Molecular Biology, Mayo College of Medicine and Science, Jacksonville, FL, USA
| | - Ramesh Nimma
- College of Pharmacy and Pharmacological Sciences, Florida A&M University, Tallahassee, FL, USA
| | - Yan Li
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, USA.
| | - Deepak A Lamba
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA.
| | - Mandip Singh
- College of Pharmacy and Pharmacological Sciences, Florida A&M University, Tallahassee, FL, USA.
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17
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Majchrakova Z, Hrckova Turnova E, Bielikova M, Turna J, Dudas A. The incidence of genetic disease alleles in Australian Shepherd dog breed in European countries. PLoS One 2023; 18:e0281215. [PMID: 36848350 PMCID: PMC9970066 DOI: 10.1371/journal.pone.0281215] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 01/18/2023] [Indexed: 03/01/2023] Open
Abstract
Genetic disease control is generally not given the importance it deserves. Information about what percentage of individuals carry a disorder-causing mutation is crucial for breeders to produce healthy offspring and maintain a healthy dog population of a particular breed. This study aims to provide information about the incidence of mutant alleles for the most frequently occurring hereditary diseases in the Australian Shepherd dog breed (AS). The samples were collected during a 10-years period (2012-2022) in the European population of the AS. Mutant alleles and incidence were calculated from all the obtained data for all the diseases, specifically: collie eye anomaly (9.71%), canine multifocal retinopathy type 1 (0.53%), hereditary cataract (11.64%), progressive rod-cone degeneration (1.58%), degenerative myelopathy (11.77%) and bob-tail/short-tail (31.74%). Our data provide more information to dog breeders to support their effort to limit the spread of hereditary diseases.
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Affiliation(s)
| | | | - Marcela Bielikova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Jan Turna
- Comenius University Science Park, Bratislava, Slovakia,Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Andrej Dudas
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia,* E-mail:
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18
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Cellular and Molecular Mechanisms of Pathogenesis Underlying Inherited Retinal Dystrophies. Biomolecules 2023; 13:biom13020271. [PMID: 36830640 PMCID: PMC9953031 DOI: 10.3390/biom13020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation.
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19
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Motipally SI, Kolandaivelu S. Absence of PRCD Leads to Dysregulation in Lipid Homeostasis Resulting in Disorganization of Photoreceptor Outer Segment Structure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:389-394. [PMID: 37440062 DOI: 10.1007/978-3-031-27681-1_57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
The outer segments of photoreceptors are specialized sensory cilia crucial for light detection. Any disruption that alters outer segment morphology can impair photoreceptor function and therefore vision. Progressive rod-cone degeneration (PRCD) is an integral membrane protein exclusively present in the photoreceptor OS with an unknown function. Multiple mutations in PRCD are linked with retinitis pigmentosa. The most common PRCD mutation observed in both human and multiple dog breeds, PRCD-C2Y, lacks the lipid modification "palmitoylation," which is crucial for protein stability and trafficking to the OS. Previous studies including ours show impaired disc morphogenesis and rhodopsin distributions in the absence of PRCD, but the precise role of PRCD in maintaining OS structure and function remains unclear. In this chapter, we discuss the potential role of PRCD in the maintenance of photoreceptor OS structural and functional integrity.
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Affiliation(s)
- Sree I Motipally
- Departments of Neuroscience and Biochemistry, Robert C. Byrd Health Sciences Centre, WVU Eye Institute, Morgantown, WV, USA
| | - Saravanan Kolandaivelu
- Departments of Ophthalmology, Visual Sciences and Biochemistry, Robert C. Byrd Health Sciences Centre, WVU Eye Institute, Morgantown, WV, USA.
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20
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Kurzawa‐Akanbi M, Whitfield P, Burté F, Bertelli PM, Pathak V, Doherty M, Hilgen B, Gliaudelytė L, Platt M, Queen R, Coxhead J, Porter A, Öberg M, Fabrikova D, Davey T, Beh CS, Georgiou M, Collin J, Boczonadi V, Härtlova A, Taggart M, Al‐Aama J, Korolchuk VI, Morris CM, Guduric‐Fuchs J, Steel DH, Medina RJ, Armstrong L, Lako M. Retinal pigment epithelium extracellular vesicles are potent inducers of age-related macular degeneration disease phenotype in the outer retina. J Extracell Vesicles 2022; 11:e12295. [PMID: 36544284 PMCID: PMC9772497 DOI: 10.1002/jev2.12295] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 11/18/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness. Vision loss is caused by the retinal pigment epithelium (RPE) and photoreceptors atrophy and/or retinal and choroidal angiogenesis. Here we use AMD patient-specific RPE cells with the Complement Factor H Y402H high-risk polymorphism to perform a comprehensive analysis of extracellular vesicles (EVs), their cargo and role in disease pathology. We show that AMD RPE is characterised by enhanced polarised EV secretion. Multi-omics analyses demonstrate that AMD RPE EVs carry RNA, proteins and lipids, which mediate key AMD features including oxidative stress, cytoskeletal dysfunction, angiogenesis and drusen accumulation. Moreover, AMD RPE EVs induce amyloid fibril formation, revealing their role in drusen formation. We demonstrate that exposure of control RPE to AMD RPE apical EVs leads to the acquisition of AMD features such as stress vacuoles, cytoskeletal destabilization and abnormalities in the morphology of the nucleus. Retinal organoid treatment with apical AMD RPE EVs leads to disrupted neuroepithelium and the appearance of cytoprotective alpha B crystallin immunopositive cells, with some co-expressing retinal progenitor cell markers Pax6/Vsx2, suggesting injury-induced regenerative pathways activation. These findings indicate that AMD RPE EVs are potent inducers of AMD phenotype in the neighbouring RPE and retinal cells.
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Affiliation(s)
- Marzena Kurzawa‐Akanbi
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Phillip Whitfield
- Glasgow Polyomics and Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Florence Burté
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Pietro Maria Bertelli
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - Varun Pathak
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - Mary Doherty
- Lipidomics Research FacilityUniversity of the Highlands and IslandsInvernessUK
| | - Birthe Hilgen
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Lina Gliaudelytė
- Translational and Clinical Research InstituteNewcastle UniversityNewcastle upon TyneUK
| | | | - Rachel Queen
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Jonathan Coxhead
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Andrew Porter
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Maria Öberg
- Institute of Biomedicine, Department of Microbiology and Immunology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Wallenberg Center for Molecular and Translational MedicineUniversity of GothenburgGothenburgSweden
| | - Daniela Fabrikova
- Institute of Biomedicine, Department of Microbiology and Immunology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Wallenberg Center for Molecular and Translational MedicineUniversity of GothenburgGothenburgSweden
| | - Tracey Davey
- Electron Microscopy Research ServicesNewcastle UniversityNewcastle upon TyneUK
| | - Chia Shyan Beh
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Maria Georgiou
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Joseph Collin
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Veronika Boczonadi
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Anetta Härtlova
- Institute of Biomedicine, Department of Microbiology and Immunology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Wallenberg Center for Molecular and Translational MedicineUniversity of GothenburgGothenburgSweden
- The Institute of Medical Microbiology and HygieneUniversity Medical Center Freiburg (Universitätklinikum Freiburg)FreiburgGermany
| | - Michael Taggart
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Jumana Al‐Aama
- Faculty of MedicineKing Abdulaziz UniversityJeddahSaudi Arabia
| | - Viktor I Korolchuk
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Christopher M Morris
- Translational and Clinical Research InstituteNewcastle UniversityNewcastle upon TyneUK
| | - Jasenka Guduric‐Fuchs
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - David H Steel
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Reinhold J Medina
- The Welcome‐Wolfson Institute for Experimental MedicineQueen's University BelfastBelfastUK
| | - Lyle Armstrong
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
| | - Majlinda Lako
- Biosciences Institute, Faculty of Medical SciencesNewcastle UniversityNewcastle upon TyneUK
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21
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Lewis TR, Phan S, Kim KY, Jha I, Castillo CM, Ding JD, Sajdak BS, Merriman DK, Ellisman MH, Arshavsky VY. Microvesicle release from inner segments of healthy photoreceptors is a conserved phenomenon in mammalian species. Dis Model Mech 2022; 15:dmm049871. [PMID: 36420970 PMCID: PMC9796728 DOI: 10.1242/dmm.049871] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/01/2022] [Indexed: 11/25/2022] Open
Abstract
Many inherited visual diseases arise from mutations that affect the structure and function of photoreceptor cells. In some cases, the pathology is accompanied by a massive release of extracellular vesicles from affected photoreceptors. In this study, we addressed whether vesicular release is an exclusive response to ongoing pathology or a normal homeostatic phenomenon amplified in disease. We analyzed the ultrastructure of normal photoreceptors from both rod- and cone-dominant mammalian species and found that these cells release microvesicles budding from their inner segment compartment. Inner segment-derived microvesicles vary in their content, with some of them containing the visual pigment rhodopsin and others appearing to be interconnected with mitochondria. These data suggest the existence of a fundamental process whereby healthy mammalian photoreceptors release mistrafficked or damaged inner segment material as microvesicles into the interphotoreceptor space. This release may be greatly enhanced under pathological conditions associated with defects in protein targeting and trafficking. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Tylor R. Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Sebastien Phan
- National Center for Microscopy and Imaging Research, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Isha Jha
- National Center for Microscopy and Imaging Research, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Carson M. Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Jin-Dong Ding
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Benjamin S. Sajdak
- Department of Biology, University of Wisconsin Oshkosh, Oshkosh, WI 54901, USA
- Fauna Bio Inc., Emeryville, CA 94608, USA
| | - Dana K. Merriman
- Department of Biology, University of Wisconsin Oshkosh, Oshkosh, WI 54901, USA
| | - Mark H. Ellisman
- National Center for Microscopy and Imaging Research, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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22
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Myers B, Sechrest ER, Hamner G, Motipally SI, Murphy J, Kolandaivelu S. R17C Mutation in Photoreceptor Disc-Specific Protein, PRCD, Results in Additional Lipidation Altering Protein Stability and Subcellular Localization. Int J Mol Sci 2022; 23:ijms231810802. [PMID: 36142714 PMCID: PMC9503786 DOI: 10.3390/ijms231810802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
Progressive rod-cone degeneration (PRCD) is a photoreceptor outer segment (OS) disc-specific protein essential for maintaining OS structures while contributing to rhodopsin packaging densities and distribution in disc membranes. Previously, we showed PRCD undergoing palmitoylation at the sole cysteine (Cys2), where a mutation linked with retinitis pigmentosa (RP) in humans and dogs demonstrates the importance of palmitoylation for protein stability and trafficking to the OS. We demonstrate a mutation, in the polybasic region (PBR) of PRCD (Arg17Cys) linked with RP where an additional lipidation is observed through acyl-RAC. Immunolocalization of transiently expressed R17C in hRPE1 cells depicts similar characteristics to wild-type PRCD; however, a double mutant lacking endogenous palmitoylation at Cys2Tyr with Arg17Cys is comparable to the C2Y protein as both aggregate, mislocalized to the subcellular compartments within the cytoplasm. Subretinal injection of PRCD mutant constructs followed by electroporation in murine retina exhibit mislocalization in the inner segment. Despite being additionally lipidated and demonstrating strong membrane association, the mutation in the PBR affects protein stability and localization to the OS. Acylation within the PBR alone neither compensates for protein stability nor trafficking, revealing defects in the PBR likely lead to dysregulation of PRCD protein associated with blinding diseases.
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Affiliation(s)
- Boyden Myers
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
| | - Emily R. Sechrest
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
| | - Gabrielle Hamner
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
| | - Sree I. Motipally
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
- Department of Neurosciences, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
| | - Joseph Murphy
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
| | - Saravanan Kolandaivelu
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
- Department of Biochemistry and Molecular Medicine, One Medical Center Drive, West Virginia University, Morgantown, WV 26506, USA
- Correspondence:
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23
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Ciampi L, Mantica F, López-Blanch L, Permanyer J, Rodriguez-Marín C, Zang J, Cianferoni D, Jiménez-Delgado S, Bonnal S, Miravet-Verde S, Ruprecht V, Neuhauss SCF, Banfi S, Carrella S, Serrano L, Head SA, Irimia M. Specialization of the photoreceptor transcriptome by Srrm3-dependent microexons is required for outer segment maintenance and vision. Proc Natl Acad Sci U S A 2022; 119:e2117090119. [PMID: 35858306 PMCID: PMC9303857 DOI: 10.1073/pnas.2117090119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 05/28/2022] [Indexed: 01/14/2023] Open
Abstract
Retinal photoreceptors have a distinct transcriptomic profile compared to other neuronal subtypes, likely reflecting their unique cellular morphology and function in the detection of light stimuli by way of the ciliary outer segment. We discovered a layer of this molecular specialization by revealing that the vertebrate retina expresses the largest number of tissue-enriched microexons of all tissue types. A subset of these microexons is included exclusively in photoreceptor transcripts, particularly in genes involved in cilia biogenesis and vesicle-mediated transport. This microexon program is regulated by Srrm3, a paralog of the neural microexon regulator Srrm4. Despite the fact that both proteins positively regulate retina microexons in vitro, only Srrm3 is highly expressed in mature photoreceptors. Its deletion in zebrafish results in widespread down-regulation of microexon inclusion from early developmental stages, followed by other transcriptomic alterations, severe photoreceptor defects, and blindness. These results shed light on the transcriptomic specialization and functionality of photoreceptors, uncovering unique cell type-specific roles for Srrm3 and microexons with implications for retinal diseases.
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Affiliation(s)
- Ludovica Ciampi
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Federica Mantica
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Laura López-Blanch
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Jon Permanyer
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Cristina Rodriguez-Marín
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Jingjing Zang
- Department of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Damiano Cianferoni
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Senda Jiménez-Delgado
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Sophie Bonnal
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Samuel Miravet-Verde
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Verena Ruprecht
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
- Universitat Pompeu Fabra, 08002 Barcelona, Spain
| | - Stephan C. F. Neuhauss
- Department of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Sandro Banfi
- Medical Genetics, Department of Precision Medicine, University of Campania “L. Vanvitelli”, 80138 Naples, Italy
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Sabrina Carrella
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
- Ecosustainable Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Luis Serrano
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
- Universitat Pompeu Fabra, 08002 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Sarah A. Head
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
| | - Manuel Irimia
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08036 Barcelona, Spain
- Universitat Pompeu Fabra, 08002 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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24
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Hanke-Gogokhia C, Lehmann GL, Benedicto I, de la Fuente-Ortega E, Arshavsky VY, Schreiner R, Rodriguez-Boulan E. Apical CLC-2 in retinal pigment epithelium is crucial for survival of the outer retina. FASEB J 2021; 35:e21689. [PMID: 34085737 PMCID: PMC8252757 DOI: 10.1096/fj.202100349r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 12/15/2022]
Abstract
Knockout of the chloride channel protein 2 (CLC‐2; CLCN2) results in fast progressing blindness in mice. Retinal Pigment Epithelium (RPE) and photoreceptors undergo, in parallel, rapid, and profound morphological changes and degeneration. Immunohistochemistry and electron microscopy of the outer retina and electroretinography of the CLC‐2 KO mouse demonstrated normal morphology at postnatal day 2, followed by drastic changes in RPE and photoreceptor morphology and loss of vision during the first postnatal month. To investigate whether the RPE or the photoreceptors are the primary cause of the degeneration, we injected lentiviruses carrying HA‐tagged CLC‐2 with an RPE‐specific promotor in the subretinal space of CLC‐2‐KO mice at the time of eye opening. As expected, CLC‐2‐HA was expressed exclusively in RPE; strikingly, this procedure rescued the degeneration of both RPE and photoreceptors. Light response in transduced eyes was also recovered. Only a fraction of RPE was transduced with the lentivirus; however, the entire RPE monolayer appears healthy, even the RPE cells not expressing the CLC‐2‐HA. Surprisingly, in contrast with previous physiological observations that postulate that CLC‐2 has a basolateral localization in RPE, our immunofluorescence experiments demonstrated CLC‐2 has an apical distribution, facing the subretinal space and the photoreceptor outer segments. Our findings suggest that CLC‐2 does not play the postulated role in fluid transport at the basolateral membrane. Rather, they suggest that CLC‐2 performs a critical homeostatic role in the subretinal compartment involving a chloride regulatory mechanism that is critical for the survival of both RPE and photoreceptors.
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Affiliation(s)
| | | | - Ignacio Benedicto
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Erwin de la Fuente-Ortega
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Ryan Schreiner
- Division of Regenerative Medicine, Ansary Stem Cell Institute, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Enrique Rodriguez-Boulan
- Department of Ophthalmology, Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY, USA
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25
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Sharif AS, Gerstner CD, Cady MA, Arshavsky VY, Mitchell C, Ying G, Frederick JM, Baehr W. Deletion of the phosphatase INPP5E in the murine retina impairs photoreceptor axoneme formation and prevents disc morphogenesis. J Biol Chem 2021; 296:100529. [PMID: 33711342 PMCID: PMC8047226 DOI: 10.1016/j.jbc.2021.100529] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/26/2021] [Accepted: 03/08/2021] [Indexed: 12/13/2022] Open
Abstract
INPP5E, also known as pharbin, is a ubiquitously expressed phosphatidylinositol polyphosphate 5-phosphatase that is typically located in the primary cilia and modulates the phosphoinositide composition of membranes. Mutations to or loss of INPP5E is associated with ciliary dysfunction. INPP5E missense mutations of the phosphatase catalytic domain cause Joubert syndrome in humans-a syndromic ciliopathy affecting multiple tissues including the brain, liver, kidney, and retina. In contrast to other primary cilia, photoreceptor INPP5E is prominently expressed in the inner segment and connecting cilium and absent in the outer segment, which is a modified primary cilium dedicated to phototransduction. To investigate how loss of INPP5e causes retina degeneration, we generated mice with a retina-specific KO (Inpp5eF/F;Six3Cre, abbreviated as retInpp5e-/-). These mice exhibit a rapidly progressing rod-cone degeneration resembling Leber congenital amaurosis that is nearly completed by postnatal day 21 (P21) in the central retina. Mutant cone outer segments contain vesicles instead of discs as early as P8. Although P10 mutant outer segments contain structural and phototransduction proteins, axonemal structure and disc membranes fail to form. Connecting cilia of retInpp5e-/- rods display accumulation of intraflagellar transport particles A and B at their distal ends, suggesting disrupted intraflagellar transport. Although INPP5E ablation may not prevent delivery of outer segment-specific proteins by means of the photoreceptor secretory pathway, its absence prevents the assembly of axonemal and disc components. Herein, we suggest a model for INPP5E-Leber congenital amaurosis, proposing how deletion of INPP5E may interrupt axoneme extension and disc membrane elaboration.
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Affiliation(s)
- Ali S Sharif
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Cecilia D Gerstner
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Martha A Cady
- Department of Ophthalmology, Duke University, Durham, North Carolina, USA
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University, Durham, North Carolina, USA
| | - Christina Mitchell
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Guoxin Ying
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Jeanne M Frederick
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
| | - Wolfgang Baehr
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA; Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, USA; Department of Biology, University of Utah, Salt Lake City, Utah, USA.
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26
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Turn RE, Linnert J, Gigante ED, Wolfrum U, Caspary T, Kahn RA. Roles for ELMOD2 and Rootletin in ciliogenesis. Mol Biol Cell 2021; 32:800-822. [PMID: 33596093 PMCID: PMC8108518 DOI: 10.1091/mbc.e20-10-0635] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
ELMOD2 is a GTPase-activating protein with uniquely broad specificity for ARF family GTPases. We previously showed that it acts with ARL2 in mitochondrial fusion and microtubule stability and with ARF6 during cytokinesis. Mouse embryonic fibroblasts deleted for ELMOD2 also displayed changes in cilia-related processes including increased ciliation, multiciliation, ciliary morphology, ciliary signaling, centrin accumulation inside cilia, and loss of rootlets at centrosomes with loss of centrosome cohesion. Increasing ARL2 activity or overexpressing Rootletin reversed these defects, revealing close functional links between the three proteins. This was further supported by the findings that deletion of Rootletin yielded similar phenotypes, which were rescued upon increasing ARL2 activity but not ELMOD2 overexpression. Thus, we propose that ARL2, ELMOD2, and Rootletin all act in a common pathway that suppresses spurious ciliation and maintains centrosome cohesion. Screening a number of markers of steps in the ciliation pathway supports a model in which ELMOD2, Rootletin, and ARL2 act downstream of TTBK2 and upstream of CP110 to prevent spurious release of CP110 and to regulate ciliary vesicle docking. These data thus provide evidence supporting roles for ELMOD2, Rootletin, and ARL2 in the regulation of ciliary licensing.
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Affiliation(s)
- Rachel E Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322.,Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Joshua Linnert
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität, Mainz 655099, Germany
| | - Eduardo D Gigante
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322.,Neuroscience Graduate Program, Emory University, Atlanta, GA 30322
| | - Uwe Wolfrum
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität, Mainz 655099, Germany
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Richard A Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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27
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Innate Immunity in Age-Related Macular Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1256:121-141. [PMID: 33848000 DOI: 10.1007/978-3-030-66014-7_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple lines of investigation have demonstrated that inflammation plays significant roles in etiology of age-related macular degeneration (AMD). Although interventional trials in AMD therapy targeting inflammatory pathways have been conducted, they have not yet been successful and a detailed understanding as to why some have failed is still elusive. One limitation is the relative dearth of information on how immune cells interact with retinal cells to generate AMD phenotypes at each disease stage. Here, we summarize current research evidence and hypotheses regarding potential pathogenic roles of innate immune cells in the eye, which include resident retinal microglia, macrophages derived from infiltrating systemic monocytes, and macrophages resident in the choroid. We relate recent findings regarding the physiology, function, and cellular interactions involving innate immune cells in the retina and choroid to AMD-related processes, including: (1) drusen formation and regression, (2) the onset and spread of degeneration in late atrophic AMD, and (3) the initiation, growth, and exudation of neovascular vessels in late "wet" AMD. Understanding how innate immune cells contribute to specific AMD phenotypes can assist in generating a comprehensive view on the inflammatory etiology of AMD and aid in identifying anti-inflammatory therapeutic strategies and selecting appropriate clinical outcomes for the planned interventions.
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28
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TULP1 and TUB Are Required for Specific Localization of PRCD to Photoreceptor Outer Segments. Int J Mol Sci 2020; 21:ijms21228677. [PMID: 33213002 PMCID: PMC7698587 DOI: 10.3390/ijms21228677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/11/2020] [Accepted: 11/16/2020] [Indexed: 11/28/2022] Open
Abstract
Photoreceptor disc component (PRCD) is a small protein which is exclusively localized to photoreceptor outer segments, and is involved in the formation of photoreceptor outer segment discs. Mutations in PRCD are associated with retinal degeneration in humans, mice, and dogs. The purpose of this work was to identify PRCD-binding proteins in the retina. PRCD protein-protein interactions were identified when implementing the Ras recruitment system (RRS), a cytoplasmic-based yeast two-hybrid system, on a bovine retina cDNA library. An interaction between PRCD and tubby-like protein 1 (TULP1) was identified. Co-immunoprecipitation in transfected mammalian cells confirmed that PRCD interacts with TULP1, as well as with its homolog, TUB. These interactions were mediated by TULP1 and TUB highly conserved C-terminal tubby domain. PRCD localization was altered in the retinas of TULP1- and TUB-deficient mice. These results show that TULP1 and TUB, which are involved in the vesicular trafficking of several photoreceptor proteins from the inner segment to the outer segment, are also required for PRCD exclusive localization to photoreceptor outer segment discs.
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29
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Sechrest ER, Murphy J, Senapati S, Goldberg AFX, Park PSH, Kolandaivelu S. Loss of PRCD alters number and packaging density of rhodopsin in rod photoreceptor disc membranes. Sci Rep 2020; 10:17885. [PMID: 33087780 PMCID: PMC7577997 DOI: 10.1038/s41598-020-74628-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/28/2020] [Indexed: 02/06/2023] Open
Abstract
Progressive rod-cone degeneration (PRCD) is a small protein localized to photoreceptor outer segment (OS) disc membranes. Several mutations in PRCD are linked to retinitis pigmentosa (RP) in canines and humans, and while recent studies have established that PRCD is required for high fidelity disc morphogenesis, its precise role in this process remains a mystery. To better understand the part which PRCD plays in disease progression as well as its contribution to photoreceptor OS disc morphogenesis, we generated a Prcd-KO animal model using CRISPR/Cas9. Loss of PRCD from the retina results in reduced visual function accompanied by slow rod photoreceptor degeneration. We observed a significant decrease in rhodopsin levels in Prcd-KO retina prior to photoreceptor degeneration. Furthermore, ultrastructural analysis demonstrates that rod photoreceptors lacking PRCD display disoriented and dysmorphic OS disc membranes. Strikingly, atomic force microscopy reveals that many disc membranes in Prcd-KO rod photoreceptor neurons are irregular, containing fewer rhodopsin molecules and decreased rhodopsin packing density compared to wild-type discs. This study strongly suggests an important role for PRCD in regulation of rhodopsin incorporation and packaging density into disc membranes, a process which, when dysregulated, likely gives rise to the visual defects observed in patients with PRCD-associated RP.
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Affiliation(s)
- Emily R Sechrest
- Department of Pharmaceutical Sciences, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA.,Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA
| | - Joseph Murphy
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA.,Department of Biochemistry, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA
| | - Subhadip Senapati
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | | | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Saravanan Kolandaivelu
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA. .,Department of Biochemistry, One Medical Center Drive, West Virginia University, Morgantown, WV, 26506-9193, USA.
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30
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Karlen SJ, Miller EB, Burns ME. Microglia Activation and Inflammation During the Death of Mammalian Photoreceptors. Annu Rev Vis Sci 2020; 6:149-169. [PMID: 32936734 PMCID: PMC10135402 DOI: 10.1146/annurev-vision-121219-081730] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Photoreceptors are highly specialized sensory neurons with unique metabolic and physiological requirements. These requirements are partially met by Müller glia and cells of the retinal pigment epithelium (RPE), which provide essential metabolites, phagocytose waste, and control the composition of the surrounding microenvironment. A third vital supporting cell type, the retinal microglia, can provide photoreceptors with neurotrophic support or exacerbate neuroinflammation and hasten neuronal cell death. Understanding the physiological requirements for photoreceptor homeostasis and the factors that drive microglia to best promote photoreceptor survival has important implications for the treatment and prevention of blinding degenerative diseases like retinitis pigmentosa and age-related macular degeneration.
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Affiliation(s)
- Sarah J. Karlen
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, California 95616, USA
| | - Eric B. Miller
- Center for Neuroscience, University of California, Davis, Davis, California 95616, USA
| | - Marie E. Burns
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, California 95616, USA
- Center for Neuroscience, University of California, Davis, Davis, California 95616, USA
- Department of Ophthalmology & Vision Science, University of California, Davis, Davis, California 95616, USA
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31
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Spencer WJ, Lewis TR, Pearring JN, Arshavsky VY. Photoreceptor Discs: Built Like Ectosomes. Trends Cell Biol 2020; 30:904-915. [PMID: 32900570 DOI: 10.1016/j.tcb.2020.08.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/05/2020] [Accepted: 08/11/2020] [Indexed: 01/22/2023]
Abstract
The light-sensitive outer segment organelle of the vertebrate photoreceptor cell is a modified cilium filled with hundreds of flattened 'disc' membranes that provide vast light-absorbing surfaces. The outer segment is constantly renewed with new discs added at its base every day. This continuous process is essential for photoreceptor viability. In this review, we describe recent breakthroughs in the understanding of disc morphogenesis, with a focus on the molecular mechanisms responsible for initiating disc formation from the ciliary membrane. We highlight the discoveries that this mechanism evolved from an innate ciliary process of releasing small extracellular vesicles, or ectosomes, and that both disc formation and ectosome release rely on the actin cytoskeleton.
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Affiliation(s)
- William J Spencer
- Albert Eye Research Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Tylor R Lewis
- Albert Eye Research Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Jillian N Pearring
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Vadim Y Arshavsky
- Albert Eye Research Institute, Duke University Medical Center, Durham, NC 27710, USA.
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32
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Chen HY, Kelley RA, Li T, Swaroop A. Primary cilia biogenesis and associated retinal ciliopathies. Semin Cell Dev Biol 2020; 110:70-88. [PMID: 32747192 PMCID: PMC7855621 DOI: 10.1016/j.semcdb.2020.07.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 12/19/2022]
Abstract
The primary cilium is a ubiquitous microtubule-based organelle that senses external environment and modulates diverse signaling pathways in different cell types and tissues. The cilium originates from the mother centriole through a complex set of cellular events requiring hundreds of distinct components. Aberrant ciliogenesis or ciliary transport leads to a broad spectrum of clinical entities with overlapping yet highly variable phenotypes, collectively called ciliopathies, which include sensory defects and syndromic disorders with multi-organ pathologies. For efficient light detection, photoreceptors in the retina elaborate a modified cilium known as the outer segment, which is packed with membranous discs enriched for components of the phototransduction machinery. Retinopathy phenotype involves dysfunction and/or degeneration of the light sensing photoreceptors and is highly penetrant in ciliopathies. This review will discuss primary cilia biogenesis and ciliopathies, with a focus on the retina, and the role of CP110-CEP290-CC2D2A network. We will also explore how recent technologies can advance our understanding of cilia biology and discuss new paradigms for developing potential therapies of retinal ciliopathies.
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Affiliation(s)
- Holly Y Chen
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
| | - Ryan A Kelley
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Tiansen Li
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
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33
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Ropelewski P, Imanishi Y. RPE Cells Engulf Microvesicles Secreted by Degenerating Rod Photoreceptors. eNeuro 2020; 7:ENEURO.0507-19.2020. [PMID: 32376599 PMCID: PMC7242815 DOI: 10.1523/eneuro.0507-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 04/10/2020] [Accepted: 04/24/2020] [Indexed: 01/11/2023] Open
Abstract
Rhodopsin is mislocalized to the inner segment plasma membrane (IS PM) in various blinding disorders including autosomal-dominant retinitis pigmentosa caused by class I rhodopsin mutations. In these disorders, rhodopsin-laden microvesicles are secreted into the extracellular milieu by afflicted photoreceptor cells. Using a Xenopus laevis model expressing class I mutant rhodopsin or Na+/K+-ATPase (NKA) fused to Dendra2, we fluorescently labeled the microvesicles and found retinal pigment epithelial (RPE) cells are capable of engulfing microvesicles containing rhodopsin. A unique sorting mechanism allows class I mutant rhodopsin, but not NKA, to be packaged into the microvesicles. Under normal physiological conditions, NKA is not shed as microvesicles to the extracellular space, but is degraded intracellularly. Those studies provide novel insights into protein homeostasis in the photoreceptor IS PM.
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Affiliation(s)
- Philip Ropelewski
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Yoshikazu Imanishi
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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Lewis TR, Makia MS, Kakakhel M, Al-Ubaidi MR, Arshavsky VY, Naash MI. Photoreceptor Disc Enclosure Occurs in the Absence of Normal Peripherin-2/rds Oligomerization. Front Cell Neurosci 2020; 14:92. [PMID: 32410962 PMCID: PMC7198881 DOI: 10.3389/fncel.2020.00092] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in the peripherin-2 gene (PRPH2, also known as rds) cause a heterogeneous range of autosomal dominant retinal diseases. PRPH2 encodes a photoreceptor-specific tetraspanin protein, PRPH2, that is a main structural component of the photoreceptor outer segment. PRPH2 distributes to the rims of outer segment disc membranes as they undergo the process of disc membrane enclosure. Within these rims, PRPH2 exists in homo-oligomeric form or as a hetero-oligomer with another tetraspanin protein, ROM1. While complete loss of PRPH2 prevents photoreceptor outer segment formation, mutations affecting the state of its oligomerization, including C150S, C213Y and Y141C, produce outer segment structural defects. In this study, we addressed whether any of these mutations also affect disc enclosure. We employed recently developed methodology for ultrastructural analysis of the retina, involving tissue processing with tannic acid, to assess the status of disc enclosure in knockin mouse models bearing either one or two alleles of the C150S, C213Y and Y141C PRPH2 mutations. While varying degrees of outer segment structural abnormalities were observed in each of these mouse models, they contained both newly forming “open” discs and mature “enclosed” discs. These data demonstrate that normal PRPH2 oligomerization is not essential for photoreceptor disc enclosure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, United States
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States.,College of Optometry, University of Houston, Houston, TX, United States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, United States.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, United States
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States.,College of Optometry, University of Houston, Houston, TX, United States
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Yu C, Roubeix C, Sennlaub F, Saban DR. Microglia versus Monocytes: Distinct Roles in Degenerative Diseases of the Retina. Trends Neurosci 2020; 43:433-449. [PMID: 32459994 DOI: 10.1016/j.tins.2020.03.012] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/27/2020] [Accepted: 03/25/2020] [Indexed: 01/22/2023]
Abstract
Unlike in the healthy mammalian retina, macrophages in retinal degenerative states are not solely comprised of microglia but may include monocyte-derived recruits. Recent studies have applied transgenics, lineage-tracing, and transcriptomics to help decipher the distinct roles of these two cell types in the diseasesettings of inherited retinal degenerations and age-related macular degeneration.Literature discussed here focuses on the ectopic presence of both macrophage types in the extracellular site surrounding the outer aspect ofphotoreceptor cells (i.e.,the subretinal space), which is crucially involved in the pathobiology. From these studies we propose a working model in which perturbed photoreceptor states cause microglial dominant migration to the subretinal space as a protective response, whereas the abundant presence ofmonocyte-derived cells there instead drives and accelerates pathology. The latter, we propose, is underpinned by specific genetic and nongenetic determinants that lead to a maladaptive macrophage state.
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Affiliation(s)
- Chen Yu
- Department of Ophthalmology, Duke University, Durham, NC 27710, USA
| | - Christophe Roubeix
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France
| | - Florian Sennlaub
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France.
| | - Daniel R Saban
- Department of Ophthalmology, Duke University, Durham, NC 27710, USA; Department of Immunology, Duke University,Durham, NC 27710, USA.
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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Winkler PA, Occelli LM, Petersen-Jones SM. Large Animal Models of Inherited Retinal Degenerations: A Review. Cells 2020; 9:cells9040882. [PMID: 32260251 PMCID: PMC7226744 DOI: 10.3390/cells9040882] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Studies utilizing large animal models of inherited retinal degeneration (IRD) have proven important in not only the development of translational therapeutic approaches, but also in improving our understanding of disease mechanisms. The dog is the predominant species utilized because spontaneous IRD is common in the canine pet population. Cats are also a source of spontaneous IRDs. Other large animal models with spontaneous IRDs include sheep, horses and non-human primates (NHP). The pig has also proven valuable due to the ease in which transgenic animals can be generated and work is ongoing to produce engineered models of other large animal species including NHP. These large animal models offer important advantages over the widely used laboratory rodent models. The globe size and dimensions more closely parallel those of humans and, most importantly, they have a retinal region of high cone density and denser photoreceptor packing for high acuity vision. Laboratory rodents lack such a retinal region and, as macular disease is a critical cause for vision loss in humans, having a comparable retinal region in model species is particularly important. This review will discuss several large animal models which have been used to study disease mechanisms relevant for the equivalent human IRD.
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Zhang P, Shibata B, Peinado G, Zawadzki RJ, FitzGerald P, Pugh EN. Measurement of Diurnal Variation in Rod Outer Segment Length In Vivo in Mice With the OCT Optoretinogram. Invest Ophthalmol Vis Sci 2020; 61:9. [PMID: 32176260 PMCID: PMC7401691 DOI: 10.1167/iovs.61.3.9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/25/2019] [Indexed: 12/14/2022] Open
Abstract
Purpose To investigate diurnal variation in the length of mouse rod outer segments in vivo. Methods The lengths of rod inner and outer segments (RIS, ROS) of dark-adapted albino mice maintained on a 12-hour dark:12-hour light cycle with light onset 7 AM were measured at prescribed times (6:30 AM, 11 AM, 3:30 PM) during the diurnal cycle with optical coherence tomography (OCT), taking advantage of increased visibility, after a brief bleaching exposure, of the bands corresponding to RIS/ROS boundaries and ROS tips (ROST). Results Deconvolution of OCT depth profiles resolved two backscatter bands located 7.4 ± 0.1 and 10.8 ± 0.2 µm (mean ± SEM) proximal to Bruch's membrane (BrM). These bands were identified with histology as arising from the apical surface of RPE and ROST, respectively. The average length of dark-adapted ROS at 6:30 AM was 17.7 ± 0.8 µm. By 11 AM, the average ROS length had decreased by 10% to 15.9 ± 0.7 µm. After 11 AM, the ROS length increased steadily at an average rate of 0.12 µm/h, returning to baseline length by 23.5 hours in the cycle. Conclusions The diurnal variation in ROS length measured in these experiments is consistent with prior histological investigations showing that rodent rod discs are phagocytosed by the RPE maximally over several hours around the time of normal light onset. The rate of recovery of ROS to baseline length before normal light onset is consistent with the hypothesis that disc membrane synthesis is fairly constant over the diurnal cycle.
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Affiliation(s)
- Pengfei Zhang
- UC Davis Eye-Pod, Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California, United States
| | - Bradley Shibata
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States
| | - Gabriel Peinado
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States
| | - Robert J. Zawadzki
- UC Davis Eye-Pod, Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California, United States
- Vision Science and Advanced Retinal Imaging Laboratory (VSRI), Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, California, United States
| | - Paul FitzGerald
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, United States
| | - Edward N. Pugh
- UC Davis Eye-Pod, Department of Cell Biology and Human Anatomy, University of California Davis, Davis, California, United States
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Yumnamcha T, Devi TS, Singh LP. Auranofin Mediates Mitochondrial Dysregulation and Inflammatory Cell Death in Human Retinal Pigment Epithelial Cells: Implications of Retinal Neurodegenerative Diseases. Front Neurosci 2019; 13:1065. [PMID: 31649499 PMCID: PMC6795687 DOI: 10.3389/fnins.2019.01065] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/24/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose Photoreceptor degeneration occurs in various retinal diseases including age-related macular degeneration (AMD), Retinitis pigmentosa (RP), and diabetic retinopathy (DR). However, molecular mechanisms are not fully understood yet. The retinal pigment epithelium (RPE) forms the outer blood retinal barrier (oBRB) and supplies glucose, oxygen and nutrients from the fenestrated choriocapillaris to photoreceptors for visual function. Therefore, RPE dysfunction leads to photoreceptor injury/death and progression of blinding eye diseases. This study aims to understand the role of the thioredoxin (Trx) and its reductase (TrxR) redox signaling in human RPE dysfunction and cell death mechanism(s) in an in vitro system. Methods A human RPE cell line (APRE-19) was cultured in DMEM/F12 medium and treated with auranofin (AF - 4 μM, an inhibitor of TrxR) for 4 and 24 h. Mitochondrial and lysosomal function, cellular oxidative stress and NLRP3 inflammasome activity were measured using cell assays, Western blotting, and confocal microscopy. Antioxidants and anti-inflammatory compounds were tested for blocking AF effects on RPE damage. Cell death mechanisms (LDH release to culture media) were determined using necroptosis, ferroptosis and pyroptosis inhibitors. P < 0.05 was considered significant in statistical analysis. Results Auranofin causes mitochondrial dysfunction (Δψm↓ and ATP↓), oxidative stress (H2O2↑) and mitophagic flux to lysosomes. Furthermore, the lysosomal enzyme (cathepsin L) activity is reduced while that of pro-inflammatory caspase-1 (NLRP3 inflammasome) is enhanced in ARPE-19. These effects of AF on ARPE-19 are inhibited by antioxidant N-acetylcysteine (5 mM, NAC) and significantly by a combination of SS31 (mitochondrial antioxidant) and anti-inflammatory drugs (amlexanox and tranilast). AF also causes cell death as measured by cytosolic LDH release/leakage, which is not inhibited by either ferrostatin-1 or necrostatin-1 (ferroptosis and necroptosis inhibitors, respectively). Conversely, AF-induced LDH release is significantly reduced by MCC950 and Ac-YVAD-cmk (NLRP3 and Caspase-1 inhibitors, respectively), suggesting a pro-inflammatory cell death by pyroptosis. Conclusion The Trx/TrxR redox system is critical for RPE function and viability. We previously showed that thioredoxin-interacting protein (TXNIP) is strongly induced in DR inhibiting the Trx/TrxR system and RPE dysfunction. Therefore, our results suggest that the TXNIP-Trx-TrxR redox pathway may participate in RPE dysfunction in DR and other retinal neurodegenerative diseases.
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Affiliation(s)
- Thangal Yumnamcha
- Department of Ophthalmology, Visual and Anatomical Sciences (OVAS), Wayne State University School of Medicine, Detroit, MI, United States
| | - Takhellembam Swornalata Devi
- Department of Ophthalmology, Visual and Anatomical Sciences (OVAS), Wayne State University School of Medicine, Detroit, MI, United States
| | - Lalit Pukhrambam Singh
- Department of Ophthalmology, Visual and Anatomical Sciences (OVAS), Wayne State University School of Medicine, Detroit, MI, United States
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