1
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Otsu W. [Role of endosomal pathway in the ciliary transport and the membrane organization of outer segment disc membrane in photoreceptors]. Nihon Yakurigaku Zasshi 2024; 159:203-208. [PMID: 38684400 DOI: 10.1254/fpj.23077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
A photoreceptor is a specialized neuron that is responsible for the conversion of light into an electrical signal. Photoreceptors are classified into rods and cones, and both photoreceptors possess light-sensing ciliary organelles called outer segments (OSs), anchored in the cells by a microtubule-based axoneme. The OS consists of a stack of disc membranes, which are abundant for the retinal phototransduction proteins such as rhodopsin. Recently, modern protein synchronization techniques using in vivo transfection in rodents revealed that rhodopsin transits through Rab11-positive recycling endosomes, preferentially entering the OS in the dark. Moreover, Peripherin-2 (PRPH2, also called retinal degeneration slow, RDS), a photoreceptor-specific tetraspanin protein essential for the morphogenesis of disc membranes, is delivered to the OS following complementary to that of rhodopsin. Various PRPH2 disease-causing mutations have been found in humans, and most of the mutations in the cytosolic C-terminus of PRPH2 are linked to cone-dominant macular dystrophies. It has been shown that the late endosome is the waystation that sorts newly synthesized PRPH2 into the cilium. The multiple C-terminal motifs of PRPH2 regulate its late endosome and ciliary targeting through ubiquitination and binding to an Endosomal Sorting Complexes Required for Transport (ESCRT) component, Hrs. These findings suggest that the late endosomes play an important role in the biosynthetic pathway of ciliary proteins and can be a new therapeutic target for the diseases caused by ciliary defects.
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Affiliation(s)
- Wataru Otsu
- Department of Biomedical Research Laboratory, Gifu Pharmaceutical University
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2
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Kawai K, Ho MT, Ueno Y, Abdo D, Xue C, Nonaka H, Nishida H, Honma Y, Wallace VA, Shoichet MS. Hyaluronan improves photoreceptor differentiation and maturation in human retinal organoids. Acta Biomater 2024; 181:117-132. [PMID: 38705224 DOI: 10.1016/j.actbio.2024.05.001] [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: 11/24/2023] [Revised: 04/24/2024] [Accepted: 05/01/2024] [Indexed: 05/07/2024]
Abstract
Human stem cell-derived organoids enable both disease modeling and serve as a source of cells for transplantation. Human retinal organoids are particularly important as a source of human photoreceptors; however, the long differentiation period required and lack of vascularization in the organoid often results in a necrotic core and death of inner retinal cells before photoreceptors are fully mature. Manipulating the in vitro environment of differentiating retinal organoids through the incorporation of extracellular matrix components could influence retinal development. We investigated the addition of hyaluronan (HA), a component of the interphotoreceptor matrix, as an additive to promote long-term organoid survival and enhance retinal maturation. HA treatment had a significant reduction in the proportion of proliferating (Ki67+) cells and increase in the proportion of photoreceptors (CRX+), suggesting that HA accelerated photoreceptor commitment in vitro. HA significantly upregulated genes specific to photoreceptor maturation and outer segment development. Interestingly, prolonged HA-treatment significantly decreased the length of the brush border layer compared to those in control retinal organoids, where the photoreceptor outer segments reside; however, HA-treated organoids also had more mature outer segments with organized discs structures, as revealed by transmission electron microscopy. The brush border layer length was inversely proportional to the molar mass and viscosity of the hyaluronan added. This is the first study to investigate the role of exogenous HA, viscosity, and polymer molar mass on photoreceptor maturation, emphasizing the importance of material properties on organoid culture. STATEMENT OF SIGNIFICANCE: Retinal organoids are a powerful tool to study retinal development in vitro, though like many other organoid systems, can be highly variable. In this work, Shoichet and colleagues investigated the use of hyaluronan (HA), a native component of the interphotoreceptor matrix, to improve photoreceptor maturation in developing human retinal organoids. HA promoted human photoreceptor differentiation leading to mature outer segments with disc formation and more uniform and healthy retinal organoids. These findings highlight the importance of adding components native to the developing retina to generate more physiologically relevant photoreceptors for cell therapy and in vitro models to drive drug discovery and uncover novel disease mechanisms.
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Affiliation(s)
- Kotoe Kawai
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada; Regenerative Medicine Research and Planning Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan
| | - Margaret T Ho
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada; Institute of Biomedical Engineering, University of Toronto, Canada
| | - Yui Ueno
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada; Regenerative Medicine Research and Planning Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan; Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Dhana Abdo
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada; Institute of Biomedical Engineering, University of Toronto, Canada
| | - Chang Xue
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada; Institute of Biomedical Engineering, University of Toronto, Canada
| | - Hidenori Nonaka
- Regenerative Medicine Research and Planning Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan
| | - Hiroyuki Nishida
- Regenerative Medicine Research and Planning Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan
| | - Yoichi Honma
- Regenerative Medicine Research and Planning Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan
| | - Valerie A Wallace
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Canada
| | - Molly S Shoichet
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada; Institute of Biomedical Engineering, University of Toronto, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada; Department of Chemistry, University of Toronto, Canada.
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3
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Brotherton C, Megaw R. Molecular Mechanisms Governing Sight Loss in Inherited Cone Disorders. Genes (Basel) 2024; 15:727. [PMID: 38927662 PMCID: PMC11202562 DOI: 10.3390/genes15060727] [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: 04/18/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024] Open
Abstract
Inherited cone disorders (ICDs) are a heterogeneous sub-group of inherited retinal disorders (IRDs), the leading cause of sight loss in children and working-age adults. ICDs result from the dysfunction of the cone photoreceptors in the macula and manifest as the loss of colour vision and reduced visual acuity. Currently, 37 genes are associated with varying forms of ICD; however, almost half of all patients receive no molecular diagnosis. This review will discuss the known ICD genes, their molecular function, and the diseases they cause, with a focus on the most common forms of ICDs, including achromatopsia, progressive cone dystrophies (CODs), and cone-rod dystrophies (CORDs). It will discuss the gene-specific therapies that have emerged in recent years in order to treat patients with some of the more common ICDs.
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Affiliation(s)
- Chloe Brotherton
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU1, UK;
| | - Roly Megaw
- Princess Alexandra Eye Pavilion, NHS Lothian, Chalmers St., Edinburgh EH3 9HA, UK
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Bell TA, Luce BE, Hakim P, Ananda VY, Dardari H, Nguyen TH, Monshizadeh A, Chao LH. Prominin 1 and Tweety Homology 1 both induce extracellular vesicle formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.08.566258. [PMID: 37986829 PMCID: PMC10659291 DOI: 10.1101/2023.11.08.566258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Prominin-1 (Prom1) is a five-transmembrane-pass integral membrane protein that associates with curved regions of the plasma membrane. Prom1 interacts with membrane cholesterol and actively remodels the plasma membrane. Membrane bending activity is particularly evident in photoreceptors, where Prom1 loss-of-function mutations cause failure of outer segment homeostasis, leading to cone-rod retinal dystrophy (CRRD). The Tweety Homology (Ttyh) protein family has been proposed to be homologous to Prominin, but it is not known whether Ttyh proteins have an analogous membrane-bending function. Here, we characterize the membrane-bending activity of human Prom1 and Ttyh1 in native bilayer membranes. We find that Prom1 and Ttyh1 both induce formation of extracellular vesicles (EVs) in cultured mammalian cells and that the EVs produced are physically similar. Ttyh1 is more abundant in EV membranes than Prom1 and produces EVs with membranes that are more tubulated than Prom1 EVs. We further show that Prom1 interacts more stably with membrane cholesterol than Ttyh1 and that this may contribute to membrane bending inhibition in Prom1 EVs. Intriguingly, a loss-of-function mutation in Prom1 associated with CRRD induces particularly stable cholesterol binding. These experiments provide mechanistic insight into Prominin function in CRRD and suggest that Prom and Ttyh belong to a single family of functionally related membrane-bending, EV-generating proteins.
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Affiliation(s)
- Tristan A Bell
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115
- Current Address: Generate Biomedicines, 101 South St, Somerville, MA, 02143
| | - Bridget E Luce
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Pusparanee Hakim
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Virly Y Ananda
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Hiba Dardari
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Tran H Nguyen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Arezu Monshizadeh
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Luke H Chao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115
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5
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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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6
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Moran AL, Louzao-Martinez L, Norris DP, Peters DJM, Blacque OE. Transport and barrier mechanisms that regulate ciliary compartmentalization and ciliopathies. Nat Rev Nephrol 2024; 20:83-100. [PMID: 37872350 DOI: 10.1038/s41581-023-00773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2023] [Indexed: 10/25/2023]
Abstract
Primary cilia act as cell surface antennae, coordinating cellular responses to sensory inputs and signalling molecules that regulate developmental and homeostatic pathways. Cilia are therefore critical to physiological processes, and defects in ciliary components are associated with a large group of inherited pleiotropic disorders - known collectively as ciliopathies - that have a broad spectrum of phenotypes and affect many or most tissues, including the kidney. A central feature of the cilium is its compartmentalized structure, which imparts its unique molecular composition and signalling environment despite its membrane and cytosol being contiguous with those of the cell. Such compartmentalization is achieved via active transport pathways that bring protein cargoes to and from the cilium, as well as gating pathways at the ciliary base that establish diffusion barriers to protein exchange into and out of the organelle. Many ciliopathy-linked proteins, including those involved in kidney development and homeostasis, are components of the compartmentalizing machinery. New insights into the major compartmentalizing pathways at the cilium, namely, ciliary gating, intraflagellar transport, lipidated protein flagellar transport and ciliary extracellular vesicle release pathways, have improved our understanding of the mechanisms that underpin ciliary disease and associated renal disorders.
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Affiliation(s)
- Ailis L Moran
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Laura Louzao-Martinez
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.
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7
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Tam BM, Taylor JS, Moritz OL. Identification and cellular localization in Xenopus laevis photoreceptors of three Peripherin-2 family members, Prph2, Rom1 and Gp2l, which arose from gene duplication events in the common ancestors of jawed vertebrates. Exp Eye Res 2024; 239:109760. [PMID: 38158174 DOI: 10.1016/j.exer.2023.109760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024]
Abstract
Rod and cone photoreceptors are named for the distinct morphologies of their outer segment organelles, which are either cylindrical or conical, respectively. The morphologies of the stacked disks that comprise the rod and cone outer segments also differ: rod disks are completely sealed and are discontinuous from the plasma membrane, while cone disks remain partially open to the extracellular space. These morphological differences between photoreceptor types are more prominent in non-mammalian vertebrates, whose cones typically possess a greater proportion of open disks and are more tapered in shape. In mammals, the tetraspanin prph2 generates and maintains the highly curved disk rim regions by forming extended oligomeric structures with itself and a structurally similar paralog, rom1. Here we determined that in addition to these two proteins, there is a third Prph2 family paralog in most non-mammalian vertebrate species, including X. laevis: Glycoprotein 2-like protein or "Gp2l". A survey of multiple genome databases revealed a single invertebrate Prph2 'pro-ortholog' in Amphioxus, several echinoderms and in a diversity of protostomes indicating an ancient divergence from other tetraspanins. Based on phylogenetic analysis, duplication of the vertebrate predecessor likely gave rise to the Gp2l and Prph2/Rom1 clades, with a further duplication distinguishing the Prph2 and Rom1 clades. Mammals have lost Gp2l and their Rom1 has undergone a period of accelerated evolution such that it has lost several features that are retained in non-mammalian vertebrate Rom1. Specifically, Prph2, Gp2l and non-mammalian Rom1 encode proteins with consensus N-linked glycosylation and outer segment localization signals; mammalian rom1 lacks these motifs. We determined that X. laevis gp2l is expressed exclusively in cones and green rods, while X. laevis rom1 is expressed exclusively in rods, and prph2 is present in both rods and cones. The presence of three Prph2-related genes with distinct expression patterns as well as the rapid evolution of mammalian Rom1, may contribute to the more pronounced differences in morphology between rod and cone outer segments and rod and cone disks observed in non-mammalian versus mammalian vertebrates.
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Affiliation(s)
- Beatrice M Tam
- University of British Columbia, Dept of Ophthalmology & Visual Sciences, Canada
| | | | - Orson L Moritz
- University of British Columbia, Dept of Ophthalmology & Visual Sciences, Canada.
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8
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Gupta M, Pazour GJ. Intraflagellar transport: A critical player in photoreceptor development and the pathogenesis of retinal degenerative diseases. Cytoskeleton (Hoboken) 2023:10.1002/cm.21823. [PMID: 38140908 PMCID: PMC11193844 DOI: 10.1002/cm.21823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
In vertebrate vision, photons are detected by highly specialized sensory cilia called outer segments. Photoreceptor outer segments form by remodeling the membrane of a primary cilium into a stack of flattened disks. Intraflagellar transport (IFT) is critical to the formation of most types of eukaryotic cilia including the outer segments. This review covers the state of knowledge of the role of IFT in the formation and maintenance of outer segments and the human diseases that result from mutations in genes encoding the IFT complex and associated motors.
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Affiliation(s)
- Mohona Gupta
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Suite 213 Biotech II, 373 Plantation Street, Worcester MA USA 01605
- Morningside Graduate School of Biological Sciences, University of Massachusetts Chan Medical School, 55 Lake Avenue North, Worcester MA USA 01655
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Suite 213 Biotech II, 373 Plantation Street, Worcester MA USA 01605
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9
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Lewis TR, Makia MS, Castillo CM, Hao Y, Al-Ubaidi MR, Skiba NP, Conley SM, Arshavsky VY, Naash MI. ROM1 is redundant to PRPH2 as a molecular building block of photoreceptor disc rims. eLife 2023; 12:RP89444. [PMID: 37991486 PMCID: PMC10665016 DOI: 10.7554/elife.89444] [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] [Indexed: 11/23/2023] Open
Abstract
Visual signal transduction takes place within a stack of flattened membranous 'discs' enclosed within the light-sensitive photoreceptor outer segment. The highly curved rims of these discs, formed in the process of disc enclosure, are fortified by large hetero-oligomeric complexes of two homologous tetraspanin proteins, PRPH2 (a.k.a. peripherin-2 or rds) and ROM1. While mutations in PRPH2 affect the formation of disc rims, the role of ROM1 remains poorly understood. In this study, we found that the knockout of ROM1 causes a compensatory increase in the disc content of PRPH2. Despite this increase, discs of ROM1 knockout mice displayed a delay in disc enclosure associated with a large diameter and lack of incisures in mature discs. Strikingly, further increasing the level of PRPH2 rescued these morphological defects. We next showed that disc rims are still formed in a knockin mouse in which the tetraspanin body of PRPH2 was replaced with that of ROM1. Together, these results demonstrate that, despite its contribution to the formation of disc rims, ROM1 can be replaced by an excess of PRPH2 for timely enclosure of newly forming discs and establishing normal outer segment structure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of HoustonHoustonUnited States
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of HoustonHoustonUnited States
- College of Optometry, University of HoustonHoustonUnited States
| | - Nikolai P Skiba
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences CenterOklahoma CityUnited States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
| | - Muna I Naash
- Department of Biomedical Engineering, University of HoustonHoustonUnited States
- College of Optometry, University of HoustonHoustonUnited States
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10
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Wang J, Saul J, Nikonorova IA, Cruz CN, Power KM, Nguyen KC, Hall DH, Barr MM. Ciliary intrinsic mechanisms regulate dynamic ciliary extracellular vesicle release from sensory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.01.565151. [PMID: 37961114 PMCID: PMC10635059 DOI: 10.1101/2023.11.01.565151] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Cilia-derived extracellular vesicles (EVs) contain signaling proteins and act in intercellular communication. Polycystin-2 (PKD-2), a transient receptor potential channel, is a conserved ciliary EVs cargo. Caenorhabditis elegans serves as a model for studying ciliary EV biogenesis and function. C. elegans males release EVs in a mechanically-induced manner and deposit PKD-2-labeled EVs onto the hermaphrodite vulva during mating, suggesting an active release process. Here, we study the dynamics of ciliary EV release using time-lapse imaging and find that cilia can sustain the release of PKD-2-labeled EVs for a two-hour duration. Intriguingly, this extended release doesn't require neuronal synaptic transmission. Instead, ciliary intrinsic mechanisms regulate PKD-2 ciliary membrane replenishment and dynamic EV release. The ciliary kinesin-3 motor KLP-6 is necessary for both initial and extended ciliary EV release, while the transition zone protein NPHP-4 is required only for sustained EV release. The dihydroceramide desaturase DEGS1/2 ortholog TTM-5 is highly expressed in the EV-releasing sensory neurons, localizes to cilia, and is required for sustained but not initial ciliary EV release, implicating ceramide in ciliary ectocytosis. The study offers a comprehensive portrait of real-time ciliary EV release, and mechanisms supporting cilia as proficient EV release platforms.
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Affiliation(s)
- Juan Wang
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Josh Saul
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Inna A. Nikonorova
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Carlos Nava Cruz
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Kaiden M. Power
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Ken C. Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - David H. Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Maureen M. Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
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11
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Gopalakrishnan J, Feistel K, Friedrich BM, Grapin‐Botton A, Jurisch‐Yaksi N, Mass E, Mick DU, Müller R, May‐Simera H, Schermer B, Schmidts M, Walentek P, Wachten D. Emerging principles of primary cilia dynamics in controlling tissue organization and function. EMBO J 2023; 42:e113891. [PMID: 37743763 PMCID: PMC10620770 DOI: 10.15252/embj.2023113891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 08/07/2023] [Accepted: 09/08/2023] [Indexed: 09/26/2023] Open
Abstract
Primary cilia project from the surface of most vertebrate cells and are key in sensing extracellular signals and locally transducing this information into a cellular response. Recent findings show that primary cilia are not merely static organelles with a distinct lipid and protein composition. Instead, the function of primary cilia relies on the dynamic composition of molecules within the cilium, the context-dependent sensing and processing of extracellular stimuli, and cycles of assembly and disassembly in a cell- and tissue-specific manner. Thereby, primary cilia dynamically integrate different cellular inputs and control cell fate and function during tissue development. Here, we review the recently emerging concept of primary cilia dynamics in tissue development, organization, remodeling, and function.
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Affiliation(s)
- Jay Gopalakrishnan
- Institute for Human Genetics, Heinrich‐Heine‐UniversitätUniversitätsklinikum DüsseldorfDüsseldorfGermany
| | - Kerstin Feistel
- Department of Zoology, Institute of BiologyUniversity of HohenheimStuttgartGermany
| | | | - Anne Grapin‐Botton
- Cluster of Excellence Physics of Life, TU DresdenDresdenGermany
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at The University Hospital Carl Gustav Carus and Faculty of Medicine of the TU DresdenDresdenGermany
| | - Nathalie Jurisch‐Yaksi
- Department of Clinical and Molecular MedicineNorwegian University of Science and TechnologyTrondheimNorway
| | - Elvira Mass
- Life and Medical Sciences Institute, Developmental Biology of the Immune SystemUniversity of BonnBonnGermany
| | - David U Mick
- Center for Molecular Signaling (PZMS), Center of Human and Molecular Biology (ZHMB)Saarland School of MedicineHomburgGermany
| | - Roman‐Ulrich Müller
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD), Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Helen May‐Simera
- Institute of Molecular PhysiologyJohannes Gutenberg‐UniversityMainzGermany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD), Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Miriam Schmidts
- Pediatric Genetics Division, Center for Pediatrics and Adolescent MedicineUniversity Hospital FreiburgFreiburgGermany
- CIBSS‐Centre for Integrative Biological Signalling StudiesUniversity of FreiburgFreiburgGermany
| | - Peter Walentek
- CIBSS‐Centre for Integrative Biological Signalling StudiesUniversity of FreiburgFreiburgGermany
- Renal Division, Internal Medicine IV, Medical CenterUniversity of FreiburgFreiburgGermany
| | - Dagmar Wachten
- Institute of Innate Immunity, Biophysical Imaging, Medical FacultyUniversity of BonnBonnGermany
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12
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Masek M, Bachmann-Gagescu R. Control of protein and lipid composition of photoreceptor outer segments-Implications for retinal disease. Curr Top Dev Biol 2023; 155:165-225. [PMID: 38043951 DOI: 10.1016/bs.ctdb.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Vision is arguably our most important sense, and its loss brings substantial limitations to daily life for affected individuals. Light is perceived in retinal photoreceptors (PRs), which are highly specialized neurons subdivided into several compartments with distinct functions. The outer segments (OSs) of photoreceptors represent highly specialized primary ciliary compartments hosting the phototransduction cascade, which transforms incoming light into a neuronal signal. Retinal disease can result from various pathomechanisms originating in distinct subcompartments of the PR cell, or in the retinal pigment epithelium which supports the PRs. Dysfunction of primary cilia causes human disorders known as "ciliopathies", in which retinal disease is a common feature. This chapter focuses on PR OSs, discussing the mechanisms controlling their complex structure and composition. A sequence of tightly regulated sorting and trafficking events, both upstream of and within this ciliary compartment, ensures the establishment and maintenance of the adequate proteome and lipidome required for signaling in response to light. We discuss in particular our current understanding of the role of ciliopathy proteins involved in multi-protein complexes at the ciliary transition zone (CC2D2A) or BBSome (BBS1) and how their dysfunction causes retinal disease. While the loss of CC2D2A prevents the fusion of vesicles and delivery of the photopigment rhodopsin to the ciliary base, leading to early OS ultrastructural defects, BBS1 deficiency results in precocious accumulation of cholesterol in mutant OSs and decreased visual function preceding morphological changes. These distinct pathomechanisms underscore the central role of ciliary proteins involved in multiple processes controlling OS protein and lipid composition.
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Affiliation(s)
- Markus Masek
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland; University Research Priority Program AdaBD, University of Zurich, Zurich, Switzerland.
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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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Lewis TR, Makia MS, Castillo CM, Hao Y, Al-Ubaidi MR, Skiba NP, Conley SM, Arshavsky VY, Naash MI. ROM1 is redundant to PRPH2 as a molecular building block of photoreceptor disc rims. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.02.547380. [PMID: 37693615 PMCID: PMC10491102 DOI: 10.1101/2023.07.02.547380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Visual signal transduction takes place within a stack of flattened membranous "discs" enclosed within the light-sensitive photoreceptor outer segment. The highly curved rims of these discs, formed in the process of disc enclosure, are fortified by large hetero-oligomeric complexes of two homologous tetraspanin proteins, PRPH2 (a.k.a. peripherin-2 or rds) and ROM1. While mutations in PRPH2 affect the formation of disc rims, the role of ROM1 remains poorly understood. In this study, we found that the knockout of ROM1 causes a compensatory increase in the disc content of PRPH2. Despite this increase, discs of ROM1 knockout mice displayed a delay in disc enclosure associated with a large diameter and lack of incisures in mature discs. Strikingly, further increasing the level of PRPH2 rescued these morphological defects. We next showed that disc rims are still formed in a knockin mouse in which the tetraspanin body of PRPH2 was replaced with that of ROM1. Together, these results demonstrate that, despite its contribution to the formation of disc rims, ROM1 can be replaced by an excess of PRPH2 for timely enclosure of newly forming discs and establishing normal outer segment structure.
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Affiliation(s)
- Tylor R. Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Mustafa S. Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA, 77204
| | - Carson M. Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA, 77204
- College of Optometry, University of Houston, Houston, TX, USA, 77204
| | - Nikolai P. Skiba
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA, 73104
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA, 27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA, 27710
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA, 77204
- College of Optometry, University of Houston, Houston, TX, USA, 77204
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15
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Derderian C, Canales GI, Reiter JF. Seriously cilia: A tiny organelle illuminates evolution, disease, and intercellular communication. Dev Cell 2023; 58:1333-1349. [PMID: 37490910 PMCID: PMC10880727 DOI: 10.1016/j.devcel.2023.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 01/18/2023] [Accepted: 06/30/2023] [Indexed: 07/27/2023]
Abstract
The borders between cell and developmental biology, which have always been permeable, have largely dissolved. One manifestation is the blossoming of cilia biology, with cell and developmental approaches (increasingly complemented by human genetics, structural insights, and computational analysis) fruitfully advancing understanding of this fascinating, multifunctional organelle. The last eukaryotic common ancestor probably possessed a motile cilium, providing evolution with ample opportunity to adapt cilia to many jobs. Over the last decades, we have learned how non-motile, primary cilia play important roles in intercellular communication. Reflecting their diverse motility and signaling functions, compromised cilia cause a diverse range of diseases collectively called "ciliopathies." In this review, we highlight how cilia signal, focusing on how second messengers generated in cilia convey distinct information; how cilia are a potential source of signals to other cells; how evolution may have shaped ciliary function; and how cilia research may address thorny outstanding questions.
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Affiliation(s)
- Camille Derderian
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Gabriela I Canales
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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16
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Ikelle L, Makia M, Lewis T, Crane R, Kakakhel M, Conley SM, Birtley JR, Arshavsky VY, Al-Ubaidi MR, Naash MI. Comparative study of PRPH2 D2 loop mutants reveals divergent disease mechanism in rods and cones. Cell Mol Life Sci 2023; 80:214. [PMID: 37466729 PMCID: PMC10356684 DOI: 10.1007/s00018-023-04851-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/10/2023] [Accepted: 06/28/2023] [Indexed: 07/20/2023]
Abstract
Mutations in the photoreceptor-specific tetraspanin gene peripherin-2 (PRPH2) lead to widely varying forms of retinal degeneration ranging from retinitis pigmentosa to macular dystrophy. Both inter- and intra-familial phenotypic heterogeneity has led to much interest in uncovering the complex pathogenic mechanisms of PRPH2-associated disease. Majority of disease-causing mutations in PRPH2 reside in the second intradiscal loop, wherein seven cysteines control protein folding and oligomerization. Here, we utilize knockin models to evaluate the role of three D2 loop cysteine mutants (Y141C, C213Y and C150S), alone or in combination. We elucidated how these mutations affect PRPH2 properties, including oligomerization and subcellular localization, and contribute to disease processes. Results from our structural, functional and molecular studies revealed that, in contrast to our understanding from prior investigations, rods are highly affected by PRPH2 mutations interfering with oligomerization and not merely by the haploinsufficiency associated with these mutations. On the other hand, cones are less affected by the toxicity of the mutant protein and significantly reduced protein levels, suggesting that knockdown therapeutic strategies may sustain cone functionality for a longer period. This observation provides useful data to guide and simplify the current development of effective therapeutic approaches for PRPH2-associated diseases that combine knockdown with high levels of gene supplementation needed to generate prolonged rod improvement.
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Affiliation(s)
- Larissa Ikelle
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Mustafa Makia
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Tylor Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Ryan Crane
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | | | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA.
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA.
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17
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Lewis TR, Phan S, Castillo CM, Kim KY, Coppenrath K, Thomas W, Hao Y, Skiba NP, Horb ME, Ellisman MH, Arshavsky VY. Photoreceptor disc incisures form as an adaptive mechanism ensuring the completion of disc enclosure. eLife 2023; 12:e89160. [PMID: 37449984 PMCID: PMC10361718 DOI: 10.7554/elife.89160] [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: 05/05/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023] Open
Abstract
The first steps of vision take place within a stack of tightly packed disc-shaped membranes, or 'discs', located in the outer segment compartment of photoreceptor cells. In rod photoreceptors, discs are enclosed inside the outer segment and contain deep indentations in their rims called 'incisures'. The presence of incisures has been documented in a variety of species, yet their role remains elusive. In this study, we combined traditional electron microscopy with three-dimensional electron tomography to demonstrate that incisures are formed only after discs become completely enclosed. We also observed that, at the earliest stage of their formation, discs are not round as typically depicted but rather are highly irregular in shape and resemble expanding lamellipodia. Using genetically manipulated mice and frogs and measuring outer segment protein abundances by quantitative mass spectrometry, we further found that incisure size is determined by the molar ratio between peripherin-2, a disc rim protein critical for the process of disc enclosure, and rhodopsin, the major structural component of disc membranes. While a high perpherin-2 to rhodopsin ratio causes an increase in incisure size and structural complexity, a low ratio precludes incisure formation. Based on these data, we propose a model whereby normal rods express a modest excess of peripherin-2 over the amount required for complete disc enclosure in order to ensure that this important step of disc formation is accomplished. Once the disc is enclosed, the excess peripherin-2 incorporates into the rim to form an incisure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Sebastien Phan
- National Center for Microscopy and Imaging Research, School of Medicine, University of California, San DiegoLa JollaUnited States
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, School of Medicine, University of California, San DiegoLa JollaUnited States
| | - Kelsey Coppenrath
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus ResourceWoods HoleUnited States
| | - William Thomas
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus ResourceWoods HoleUnited States
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Nikolai P Skiba
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
| | - Marko E Horb
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus ResourceWoods HoleUnited States
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, School of Medicine, University of California, San DiegoLa JollaUnited States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical CenterDurhamUnited States
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
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18
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Dixson AC, Dawson TR, Di Vizio D, Weaver AM. Context-specific regulation of extracellular vesicle biogenesis and cargo selection. Nat Rev Mol Cell Biol 2023; 24:454-476. [PMID: 36765164 PMCID: PMC10330318 DOI: 10.1038/s41580-023-00576-0] [Citation(s) in RCA: 124] [Impact Index Per Article: 124.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2023] [Indexed: 02/12/2023]
Abstract
To coordinate, adapt and respond to biological signals, cells convey specific messages to other cells. An important aspect of cell-cell communication involves secretion of molecules into the extracellular space. How these molecules are selected for secretion has been a fundamental question in the membrane trafficking field for decades. Recently, extracellular vesicles (EVs) have been recognized as key players in intercellular communication, carrying not only membrane proteins and lipids but also RNAs, cytosolic proteins and other signalling molecules to recipient cells. To communicate the right message, it is essential to sort cargoes into EVs in a regulated and context-specific manner. In recent years, a wealth of lipidomic, proteomic and RNA sequencing studies have revealed that EV cargo composition differs depending upon the donor cell type, metabolic cues and disease states. Analyses of distinct cargo 'fingerprints' have uncovered mechanistic linkages between the activation of specific molecular pathways and cargo sorting. In addition, cell biology studies are beginning to reveal novel biogenesis mechanisms regulated by cellular context. Here, we review context-specific mechanisms of EV biogenesis and cargo sorting, focusing on how cell signalling and cell state influence which cellular components are ultimately targeted to EVs.
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Affiliation(s)
- Andrew C Dixson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - T Renee Dawson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Center for Extracellular Vesicle Research, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Dolores Di Vizio
- Department of Surgery, Division of Cancer Biology and Therapeutics, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alissa M Weaver
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Center for Extracellular Vesicle Research, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.
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19
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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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20
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Nuzhat N, Van Schil K, Liakopoulos S, Bauwens M, Rey AD, Käseberg S, Jäger M, Willer JR, Winter J, Truong HM, Gruartmoner N, Van Heetvelde M, Wolf J, Merget R, Grasshoff-Derr S, Van Dorpe J, Hoorens A, Stöhr H, Mansard L, Roux AF, Langmann T, Dannhausen K, Rosenkranz D, Wissing KM, Van Lint M, Rossmann H, Häuser F, Nürnberg P, Thiele H, Zechner U, Pearring JN, De Baere E, Bolz HJ. CEP162 deficiency causes human retinal degeneration and reveals a dual role in ciliogenesis and neurogenesis. J Clin Invest 2023; 133:e161156. [PMID: 36862503 PMCID: PMC10104899 DOI: 10.1172/jci161156] [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: 04/18/2022] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Defects in primary or motile cilia result in a variety of human pathologies, and retinal degeneration is frequently associated with these so-called ciliopathies. We found that homozygosity for a truncating variant in CEP162, a centrosome and microtubule-associated protein required for transition zone assembly during ciliogenesis and neuronal differentiation in the retina, caused late-onset retinitis pigmentosa in 2 unrelated families. The mutant CEP162-E646R*5 protein was expressed and properly localized to the mitotic spindle, but it was missing from the basal body in primary and photoreceptor cilia. This impaired recruitment of transition zone components to the basal body and corresponded to complete loss of CEP162 function at the ciliary compartment, reflected by delayed formation of dysmorphic cilia. In contrast, shRNA knockdown of Cep162 in the developing mouse retina increased cell death, which was rescued by expression of CEP162-E646R*5, indicating that the mutant retains its role for retinal neurogenesis. Human retinal degeneration thus resulted from specific loss of the ciliary function of CEP162.
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Affiliation(s)
- Nafisa Nuzhat
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Kristof Van Schil
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Sandra Liakopoulos
- Cologne Image Reading Center, Department of Ophthalmology, University Hospital of Cologne, Cologne, Germany
- Department of Ophthalmology, Goethe University, Frankfurt, Germany
| | - Miriam Bauwens
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Alfredo Dueñas Rey
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Stephan Käseberg
- Institute of Human Genetics, University Medical Center Mainz, Mainz, Germany
| | - Melanie Jäger
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
- Augenarztpraxis Bad Brückenau, Bad Brückenau, Germany
| | | | - Jennifer Winter
- Institute of Human Genetics, University Medical Center Mainz, Mainz, Germany
| | - Hanh M. Truong
- Cell and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Nuria Gruartmoner
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Mattias Van Heetvelde
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | | | | | | | - Jo Van Dorpe
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
- Department of Pathology, Ghent University Hospital, Ghent, Belgium
| | - Anne Hoorens
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
- Department of Pathology, Ghent University Hospital, Ghent, Belgium
| | - Heidi Stöhr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Luke Mansard
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Anne-Françoise Roux
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Katharina Dannhausen
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - David Rosenkranz
- Senckenberg Centre for Human Genetics, Frankfurt am Main, Germany
| | | | - Michel Van Lint
- Department of Ophthalmology, Brussels University Hospital, Jette, Belgium
| | - Heidi Rossmann
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Mainz, Mainz, Germany
| | - Friederike Häuser
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Mainz, Mainz, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Ulrich Zechner
- Institute of Human Genetics, University Medical Center Mainz, Mainz, Germany
- Senckenberg Centre for Human Genetics, Frankfurt am Main, Germany
| | - Jillian N. Pearring
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Ophthalmology and
- Cell and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Elfride De Baere
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Hanno J. Bolz
- Senckenberg Centre for Human Genetics, Frankfurt am Main, Germany
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
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21
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Lewis TR, Phan S, Castillo CM, Kim KY, Coppenrath K, Thomas W, Hao Y, Skiba NP, Horb ME, Ellisman MH, Arshavsky VY. Photoreceptor disc incisures form as an adaptive mechanism ensuring the completion of disc enclosure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.06.535932. [PMID: 37066355 PMCID: PMC10104153 DOI: 10.1101/2023.04.06.535932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
The first steps of vision take place within a stack of tightly packed disc-shaped membranes, or "discs", located in the outer segment compartment of photoreceptor cells. In rod photoreceptors, discs are enclosed inside the outer segment and contain deep indentations in their rims called "incisures". The presence of incisures has been documented in a variety of species, yet their role remains elusive. In this study, we combined traditional electron microscopy with three-dimensional electron tomography to demonstrate that incisures are formed only after discs become completely enclosed. We also observed that, at the earliest stage of their formation, discs are not round as typically depicted but rather are highly irregular in shape and resemble expanding lamellipodia. Using genetically manipulated mice and frogs and measuring outer segment protein abundances by quantitative mass spectrometry, we further found that incisure size is determined by the molar ratio between peripherin-2, a disc rim protein critical for the process of disc enclosure, and rhodopsin, the major structural component of disc membranes. While a high perpherin-2 to rhodopsin ratio causes an increase in incisure size and structural complexity, a low ratio precludes incisure formation. Based on these data, we propose a model whereby normal rods express a modest excess of peripherin-2 over the amount required for complete disc enclosure in order to ensure that this important step of disc formation is accomplished. Once the disc is enclosed, the excess peripherin-2 incorporates into the rim to form an incisure.
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22
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Faber S, Letteboer SJF, Junger K, Butcher R, Tammana TVS, van Beersum SEC, Ueffing M, Collin RWJ, Liu Q, Boldt K, Roepman R. PDE6D Mediates Trafficking of Prenylated Proteins NIM1K and UBL3 to Primary Cilia. Cells 2023; 12:cells12020312. [PMID: 36672247 PMCID: PMC9857354 DOI: 10.3390/cells12020312] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/02/2023] [Accepted: 01/09/2023] [Indexed: 01/18/2023] Open
Abstract
Mutations in PDE6D impair the function of its cognate protein, phosphodiesterase 6D (PDE6D), in prenylated protein trafficking towards the ciliary membrane, causing the human ciliopathy Joubert Syndrome (JBTS22) and retinal degeneration in mice. In this study, we purified the prenylated cargo of PDE6D by affinity proteomics to gain insight into PDE6D-associated disease mechanisms. By this approach, we have identified a specific set of PDE6D-interacting proteins that are involved in photoreceptor integrity, GTPase activity, nuclear import, or ubiquitination. Among these interacting proteins, we identified novel ciliary cargo proteins of PDE6D, including FAM219A, serine/threonine-protein kinase NIM1 (NIM1K), and ubiquitin-like protein 3 (UBL3). We show that NIM1K and UBL3 localize inside the cilium in a prenylation-dependent manner. Furthermore, UBL3 also localizes in vesicle-like structures around the base of the cilium. Through affinity proteomics of UBL3, we confirmed its strong interaction with PDE6D and its association with proteins that regulate small extracellular vesicles (sEVs) and ciliogenesis. Moreover, we show that UBL3 localizes in specific photoreceptor cilium compartments in a prenylation-dependent manner. Therefore, we propose that UBL3 may play a role in the sorting of proteins towards the photoreceptor outer segment, further explaining the development of PDE6D-associated retinal degeneration.
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Affiliation(s)
- Siebren Faber
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Stef J. F. Letteboer
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Katrin Junger
- Division of Experimental Ophthalmology and Medical Proteome Center, Center of Ophthalmology, University of Tübingen, 72076 Tübingen, Germany
| | - Rossano Butcher
- Department of Ophthalmology, Ocular Genomics Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02115, USA
| | - Trinadh V. Satish Tammana
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Sylvia E. C. van Beersum
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Marius Ueffing
- Division of Experimental Ophthalmology and Medical Proteome Center, Center of Ophthalmology, University of Tübingen, 72076 Tübingen, Germany
| | - Rob W. J. Collin
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Qin Liu
- Department of Ophthalmology, Ocular Genomics Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02115, USA
| | - Karsten Boldt
- Division of Experimental Ophthalmology and Medical Proteome Center, Center of Ophthalmology, University of Tübingen, 72076 Tübingen, Germany
| | - Ronald Roepman
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Correspondence:
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23
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Kalargyrou AA, Guilfoyle SE, Smith AJ, Ali RR, Pearson RA. Extracellular vesicles in the retina - putative roles in physiology and disease. Front Mol Neurosci 2023; 15:1042469. [PMID: 36710933 PMCID: PMC9877344 DOI: 10.3389/fnmol.2022.1042469] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/22/2022] [Indexed: 01/15/2023] Open
Abstract
The retina encompasses a network of neurons, glia and epithelial and vascular endothelia cells, all coordinating visual function. Traditionally, molecular information exchange in this tissue was thought to be orchestrated by synapses and gap junctions. Recent findings have revealed that many cell types are able to package and share molecular information via extracellular vesicles (EVs) and the technological advancements in visualisation and tracking of these delicate nanostructures has shown that the role of EVs in cell communication is pleiotropic. EVs are released under physiological conditions by many cells but they are also released during various disease stages, potentially reflecting the health status of the cells in their cargo. Little is known about the physiological role of EV release in the retina. However, administration of exogenous EVs in vivo after injury suggest a neurotrophic role, whilst photoreceptor transplantation in early stages of retina degeneration, EVs may facilitate interactions between photoreceptors and Müller glia cells. In this review, we consider some of the proposed roles for EVs in retinal physiology and discuss current evidence regarding their potential impact on ocular therapies via gene or cell replacement strategies and direct intraocular administration in the diseased eye.
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Affiliation(s)
- Aikaterini A. Kalargyrou
- King’s College London, Guy’s Hospital, Centre for Gene Therapy and Regenerative Medicine, London, United Kingdom
| | - Siobhan E. Guilfoyle
- King’s College London, Guy’s Hospital, Centre for Gene Therapy and Regenerative Medicine, London, United Kingdom
| | - Alexander J. Smith
- King’s College London, Guy’s Hospital, Centre for Gene Therapy and Regenerative Medicine, London, United Kingdom
| | - Robin R. Ali
- King’s College London, Guy’s Hospital, Centre for Gene Therapy and Regenerative Medicine, London, United Kingdom
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States
| | - Rachael A. Pearson
- King’s College London, Guy’s Hospital, Centre for Gene Therapy and Regenerative Medicine, London, United Kingdom
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24
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Lewis TR, Al-Ubaidi MR, Naash MI, Arshavsky VY. The Role of Peripherin-2/ROM1 Complexes in Photoreceptor Outer Segment Disc Morphogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:277-281. [PMID: 37440045 DOI: 10.1007/978-3-031-27681-1_40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
The light-sensitive outer segment organelle of photoreceptor cells contains a stack of hundreds of flat, disc-shaped membranes called discs. The rims of these discs contain a photoreceptor-specific tetraspanin protein peripherin-2 (also known as rds or PRPH2). Mutations in the PRPH2 gene lead to a wide variety of inherited retinal degenerations in humans. The vast majority of these mutations occur within a large, intradiscal loop of peripherin-2, known as the D2 loop. The D2 loop mediates well-established intermolecular interactions of peripherin-2 molecules among themselves and a homologous protein ROM1. These interactions lead to the formation of large, highly ordered oligomers. In this chapter, we discuss the supramolecular organization of peripherin-2/ROM1 complexes and their contribution to the process of outer segment disc morphogenesis and enclosure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA.
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, College of Engineering, University of Houston, Houston, TX, USA
- College of Optometry, University of Houston, Houston, TX, USA
| | - Muna I Naash
- Department of Biomedical Engineering, College of Engineering, University of Houston, Houston, TX, USA
- College of Optometry, University of Houston, Houston, TX, USA
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
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25
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El Mazouni D, Gros P. Cryo-EM structures of peripherin-2 and ROM1 suggest multiple roles in photoreceptor membrane morphogenesis. SCIENCE ADVANCES 2022; 8:eadd3677. [PMID: 36351012 PMCID: PMC9645710 DOI: 10.1126/sciadv.add3677] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Mammalian peripherin-2 (PRPH2) and rod outer segment membrane protein 1 (ROM1) are retina-specific tetraspanins that partake in the constant renewal of stacked membrane discs of photoreceptor cells that enable vision. Here, we present single-particle cryo-electron microscopy structures of solubilized PRPH2-ROM1 heterodimers and higher-order oligomers. High-risk PRPH2 and ROM1 mutations causing blindness map to the protein-dimer interface. Cysteine bridges connect dimers forming positive-curved oligomers, whereas negative-curved oligomers were observed occasionally. Hexamers and octamers exhibit a secondary micelle that envelopes four carboxyl-terminal helices, supporting a potential role in membrane remodeling. Together, the data indicate multiple structures for PRPH2-ROM1 in creating and maintaining compartmentalization of photoreceptor cells.
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Affiliation(s)
- Dounia El Mazouni
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Netherlands
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26
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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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27
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Abstract
Cilia sense and transduce sensory stimuli, homeostatic cues and developmental signals by orchestrating signaling reactions. Extracellular vesicles (EVs) that bud from the ciliary membrane have well-studied roles in the disposal of excess ciliary material, most dramatically exemplified by the shedding of micrometer-sized blocks by photoreceptors. Shedding of EVs by cilia also affords cells with a powerful means to shorten cilia. Finally, cilium-derived EVs may enable cell-cell communication in a variety of organisms, ranging from single-cell parasites and algae to nematodes and vertebrates. Mechanistic understanding of EV shedding by cilia is an active area of study, and future progress may open the door to testing the function of ciliary EV shedding in physiological contexts. In this Cell Science at a Glance and the accompanying poster, we discuss the molecular mechanisms that drive the shedding of ciliary material into the extracellular space, the consequences of shedding for the donor cell and the possible roles that ciliary EVs may have in cell non-autonomous contexts.
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Affiliation(s)
- Irene Ojeda Naharros
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143-3120, USA
| | - Maxence V. Nachury
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143-3120, USA
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28
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Inaba M, Ridwan SM, Antel M. Removal of cellular protrusions. Semin Cell Dev Biol 2022; 129:126-134. [PMID: 35260295 PMCID: PMC9378436 DOI: 10.1016/j.semcdb.2022.02.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 02/08/2023]
Abstract
Cell-cell communications are central to a variety of physiological and pathological processes in multicellular organisms. Cells often rely on cellular protrusions to communicate with one another, which enable highly selective and efficient signaling within complex tissues. Owing to significant improvements in imaging techniques, identification of signaling protrusions has increased in recent years. These protrusions are structurally specialized for signaling and facilitate interactions between cells. Therefore, physical regulation of these structures must be key for the appropriate strength and pattern of signaling outcomes. However, the typical approaches for understanding signaling regulation tend to focus solely on changes in signaling molecules, such as gene expression, protein-protein interaction, and degradation. In this short review, we summarize the studies proposing the removal of different types of signaling protrusions-including cilia, neurites, MT (microtubule based)-nanotubes and microvilli-and discuss their mechanisms and significance in signaling regulation.
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Affiliation(s)
- Mayu Inaba
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA.
| | - Sharif M Ridwan
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Matthew Antel
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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29
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Luxmi R, King SM. Cilia-derived vesicles: An ancient route for intercellular communication. Semin Cell Dev Biol 2022; 129:82-92. [PMID: 35346578 PMCID: PMC9378432 DOI: 10.1016/j.semcdb.2022.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/10/2022] [Accepted: 03/10/2022] [Indexed: 12/11/2022]
Abstract
Extracellular vesicles (EVs) provide a mechanism for intercellular communication that transports complex signals in membrane delimited structures between cells, tissues and organisms. Cells secrete EVs of various subtypes defined by the pathway leading to release and by the pathological condition of the cell. Cilia are evolutionarily conserved organelles that can act as sensory structures surveilling the extracellular environment. Here we discuss the secretory functions of cilia and their biological implications. Studies in multiple species - from the nematode Caenorhabditis elegans and the chlorophyte alga Chlamydomonas reinhardtii to mammals - have revealed that cilia shed bioactive EVs (ciliary EVs or ectosomes) by outward budding of the ciliary membrane. The content of ciliary EVs is distinct from that of other vesicles released by cells. Peptides regulate numerous aspects of metazoan physiology and development through evolutionarily conserved mechanisms. Intriguingly, cilia-derived vesicles have recently been found to mediate peptidergic signaling. C. reinhardtii releases the peptide α-amidating enzyme (PAM), bioactive amidated products and components of the peptidergic signaling machinery in ciliary EVs in a developmentally regulated manner. Considering the origin of cilia in early eukaryotes, it is likely that release of peptidergic signals in ciliary EVs represents an alternative and ancient mode of regulated secretion that cells can utilize in the absence of dedicated secretory granules.
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Affiliation(s)
- Raj Luxmi
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
| | - Stephen M King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
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30
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Demais V, Pohl A, Wunderlich KA, Pfaller AM, Kaplan L, Barthélémy A, Dittrich R, Puig B, Giebel B, Hauck SM, Pfrieger FW, Grosche A. Release of VAMP5-positive extracellular vesicles by retinal Müller glia in vivo. J Extracell Vesicles 2022; 11:e12254. [PMID: 36043482 PMCID: PMC9428896 DOI: 10.1002/jev2.12254] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/25/2022] [Accepted: 07/18/2022] [Indexed: 11/11/2022] Open
Abstract
Cell-cell interactions in the central nervous system are based on the release of molecules mediating signal exchange and providing structural and trophic support through vesicular exocytosis and the formation of extracellular vesicles. The specific mechanisms employed by each cell type in the brain are incompletely understood. Here, we explored the means of communication used by Müller cells, a type of radial glial cells in the retina, which forms part of the central nervous system. Using immunohistochemical, electron microscopic, and molecular analyses, we provide evidence for the release of distinct extracellular vesicles from endfeet and microvilli of retinal Müller cells in adult mice in vivo. We identify VAMP5 as a Müller cell-specific SNARE component that is part of extracellular vesicles and responsive to ischemia, and we reveal differences between the secretomes of immunoaffinity-purified Müller cells and neurons in vitro. Our findings suggest extracellular vesicle-based communication as an important mediator of cellular interactions in the retina.
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Affiliation(s)
- Valerie Demais
- Plateforme Imagerie In Vitro, CNRS UAR 3156, Neuropôle, University of Strasbourg, Strasbourg, France
| | - Anne Pohl
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany.,Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Kirsten A Wunderlich
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
| | - Anna M Pfaller
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
| | - Lew Kaplan
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
| | - Amelie Barthélémy
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Robin Dittrich
- Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Berta Puig
- Neurology Department, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bernd Giebel
- Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core and Research Unit Protein Science, Helmholtz-Zentrum München, München, Germany
| | - Frank W Pfrieger
- Plateforme Imagerie In Vitro, CNRS UAR 3156, Neuropôle, University of Strasbourg, Strasbourg, France.,Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Antje Grosche
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
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31
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Vinay L, Belleannée C. EV duty vehicles: Features and functions of ciliary extracellular vesicles. Front Genet 2022; 13:916233. [PMID: 36061180 PMCID: PMC9438925 DOI: 10.3389/fgene.2022.916233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/08/2022] [Indexed: 12/12/2022] Open
Abstract
The primary cilium is a microtubule-based organelle that extends from a basal body at the surface of most cells. This antenna is an efficient sensor of the cell micro-environment and is instrumental to the proper development and homeostatic control of organs. Recent compelling studies indicate that, in addition to its role as a sensor, the primary cilium also emits signals through the release of bioactive extracellular vesicles (EVs). While some primary-cilium derived EVs are released through an actin-dependent ectocytosis and are called ectosomes (or large EVs, 350–500 nm), others originate from the exocytosis of multivesicular bodies and are smaller (small EVs, 50–100 nm). Ciliary EVs carry unique signaling factors, including protein markers and microRNAs (miRNAs), and participate in intercellular communication in different organism models. This review discusses the mechanism of release, the molecular features, and functions of EVs deriving from cilia, based on the existing literature.
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32
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Daniele LL, Han JYS, Samuels IS, Komirisetty R, Mehta N, McCord JL, Yu M, Wang Y, Boesze-Battaglia K, Bell BA, Du J, Peachey NS, Philp NJ. Glucose uptake by GLUT1 in photoreceptors is essential for outer segment renewal and rod photoreceptor survival. FASEB J 2022; 36:e22428. [PMID: 35766190 PMCID: PMC9438481 DOI: 10.1096/fj.202200369r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/27/2022] [Accepted: 06/10/2022] [Indexed: 02/07/2023]
Abstract
Photoreceptors consume glucose supplied by the choriocapillaris to support phototransduction and outer segment (OS) renewal. Reduced glucose supply underlies photoreceptor cell death in inherited retinal degeneration and age-related retinal disease. We have previously shown that restricting glucose transport into the outer retina by conditional deletion of Slc2a1 encoding GLUT1 resulted in photoreceptor loss and impaired OS renewal. However, retinal neurons, glia, and the retinal pigment epithelium play specialized, synergistic roles in metabolite supply and exchange, and the cell-specific map of glucose uptake and utilization in the retina is incomplete. In these studies, we conditionally deleted Slc2a1 in a pan-retinal or rod-specific manner to better understand how glucose is utilized in the retina. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic deletion of Slc2a1 from retinal neurons and Müller glia results in reduced OS growth and progressive rod but not cone photoreceptor cell death. Rhodopsin levels were severely decreased even at postnatal day 20 when OS length was relatively normal. Arrestin levels were not changed suggesting that glucose uptake is required to synthesize membrane glycoproteins. Rod-specific deletion of Slc2a1 resulted in similar changes in OS length and rod photoreceptor cell death. These studies demonstrate that glucose is an essential carbon source for rod photoreceptor cell OS maintenance and viability.
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Affiliation(s)
- Lauren L Daniele
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - John Y S Han
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ivy S Samuels
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, USA
| | - Ravikiran Komirisetty
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Nikhil Mehta
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jessica L McCord
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Minzhong Yu
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, Penn Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brent A Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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33
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Kumar P, Zadjali F, Yao Y, Köttgen M, Hofherr A, Gross KW, Mehta D, Bissler JJ. Single Gene Mutations in Pkd1 or Tsc2 Alter Extracellular Vesicle Production and Trafficking. BIOLOGY 2022; 11:biology11050709. [PMID: 35625437 PMCID: PMC9139108 DOI: 10.3390/biology11050709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/20/2022] [Accepted: 04/30/2022] [Indexed: 12/17/2022]
Abstract
Simple Summary Extracellular vesicles shed from primary cilia may be involved in renal cystogenesis. The disruption of the Pkd1 gene in our cell culture system increased the production of EVs in a similar way that occurs when the Tsc2 gene is disrupted. Disruption of the primary cilia depresses EV production, and this may be the reason that the combined Kif3A/Pkd1 mutant mouse has a less severe phenotype than the Pkd1 mutant alone. We initiated studies aimed at understanding the renal trafficking of renally-derived EVs and found that single gene disruptions can alter the EV kinetics based on dye tracking studies. These results raise the possibility that EV features, such as cargo, dose, tissue half-life, and targeting, may be involved in the disease process, and these features may also be fertile targets for diagnostic, prognostic, and therapeutic investigation. Abstract Patients with autosomal dominant polycystic kidney disease (ADPKD) and tuberous sclerosis complex (TSC) are born with normal or near-normal kidneys that later develop cysts and prematurely lose function. Both renal cystic diseases appear to be mediated, at least in part, by disease-promoting extracellular vesicles (EVs) that induce genetically intact cells to participate in the renal disease process. We used centrifugation and size exclusion chromatography to isolate the EVs for study. We characterized the EVs using tunable resistive pulse sensing, dynamic light scattering, transmission electron microscopy, and Western blot analysis. We performed EV trafficking studies using a dye approach in both tissue culture and in vivo studies. We have previously reported that loss of the Tsc2 gene significantly increased EV production and here demonstrate that the loss of the Pkd1 gene also significantly increases EV production. Using a cell culture system, we also show that loss of either the Tsc2 or Pkd1 gene results in EVs that exhibit an enhanced uptake by renal epithelial cells and a prolonged half-life. Loss of the primary cilia significantly reduces EV production in renal collecting duct cells. Cells that have a disrupted Pkd1 gene produce EVs that have altered kinetics and a prolonged half-life, possibly impacting the duration of the EV cargo effect on the recipient cell. These results demonstrate the interplay between primary cilia and EVs and support a role for EVs in polycystic kidney disease pathogenesis.
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Affiliation(s)
- Prashant Kumar
- Department of Pediatrics, Le Bonheur Children’s Hospital, University of Tennessee Health Science Center, Memphis, TN 38103, USA; (P.K.); (F.Z.); (Y.Y.)
- Children’s Foundation Research Institute (CFRI), Le Bonheur Children’s Hospital, Memphis, TN 38103, USA
- US FDA National Center for Toxicological Research, Jefferson, AR 72079, USA;
| | - Fahad Zadjali
- Department of Pediatrics, Le Bonheur Children’s Hospital, University of Tennessee Health Science Center, Memphis, TN 38103, USA; (P.K.); (F.Z.); (Y.Y.)
- Children’s Foundation Research Institute (CFRI), Le Bonheur Children’s Hospital, Memphis, TN 38103, USA
- Department of Clinical Biochemistry, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Ying Yao
- Department of Pediatrics, Le Bonheur Children’s Hospital, University of Tennessee Health Science Center, Memphis, TN 38103, USA; (P.K.); (F.Z.); (Y.Y.)
- Children’s Foundation Research Institute (CFRI), Le Bonheur Children’s Hospital, Memphis, TN 38103, USA
| | - Michael Köttgen
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (M.K.); (A.H.)
- CIBSS—Centre for Integrative Biological Signaling Studies, 79104 Freiburg, Germany
| | - Alexis Hofherr
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (M.K.); (A.H.)
| | - Kenneth W. Gross
- Department of Molecular and Cellular Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA;
| | - Darshan Mehta
- US FDA National Center for Toxicological Research, Jefferson, AR 72079, USA;
| | - John J. Bissler
- Department of Pediatrics, Le Bonheur Children’s Hospital, University of Tennessee Health Science Center, Memphis, TN 38103, USA; (P.K.); (F.Z.); (Y.Y.)
- Children’s Foundation Research Institute (CFRI), Le Bonheur Children’s Hospital, Memphis, TN 38103, USA
- Pediatric Medicine Department, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Correspondence:
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Moran AL, Carter SP, Kaylor JJ, Jiang Z, Broekman S, Dillon ET, Gómez Sánchez A, Minhas SK, van Wijk E, Radu RA, Travis GH, Carey M, Blacque OE, Kennedy BN. Dawn and dusk peaks of outer segment phagocytosis, and visual cycle function require Rab28. FASEB J 2022; 36:e22309. [PMID: 35471581 PMCID: PMC9322422 DOI: 10.1096/fj.202101897r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/14/2022] [Accepted: 03/29/2022] [Indexed: 12/12/2022]
Abstract
RAB28 is a farnesylated, ciliary G-protein. Patient variants in RAB28 are causative of autosomal recessive cone-rod dystrophy (CRD), an inherited human blindness. In rodent and zebrafish models, the absence of Rab28 results in diminished dawn, photoreceptor, outer segment phagocytosis (OSP). Here, we demonstrate that Rab28 is also required for dusk peaks of OSP, but not for basal OSP levels. This study further elucidated the molecular mechanisms by which Rab28 controls OSP and inherited blindness. Proteomic profiling identified factors whose expression in the eye or whose expression at dawn and dusk peaks of OSP is dysregulated by loss of Rab28. Notably, transgenic overexpression of Rab28, solely in zebrafish cones, rescues the OSP defect in rab28 KO fish, suggesting rab28 gene replacement in cone photoreceptors is sufficient to regulate Rab28-OSP. Rab28 loss also perturbs function of the visual cycle as retinoid levels of 11-cRAL, 11cRP, and atRP are significantly reduced in larval and adult rab28 KO retinae (p < .05). These data give further understanding on the molecular mechanisms of RAB28-associated CRD, highlighting roles of Rab28 in both peaks of OSP, in vitamin A metabolism and in retinoid recycling.
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Affiliation(s)
- Ailís L. Moran
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Stephen P. Carter
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Joanna J. Kaylor
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Zhichun Jiang
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Sanne Broekman
- Department of OtorhinolaryngologyRadboud University Medical CenterNijmegenThe Netherlands
- Donders Institute for Brain, Cognition, and BehaviorNijmegenThe Netherlands
| | | | - Alicia Gómez Sánchez
- UCD Conway InstituteUniversity College DublinDublinIreland
- Ocupharm Diagnostic Group ResearchFaculty of Optic and OptometryUniversidad Complutense de MadridMadridSpain
| | - Sajal K. Minhas
- UCD School of Mathematics & StatisticsUniversity College DublinDublinIreland
| | - Erwin van Wijk
- Department of OtorhinolaryngologyRadboud University Medical CenterNijmegenThe Netherlands
- Donders Institute for Brain, Cognition, and BehaviorNijmegenThe Netherlands
| | - Roxana A. Radu
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Gabriel H. Travis
- Department of OphthalmologyDavid Geffen School of MedicineUCLA Stein Eye InstituteUniversity of California Los AngelesLos AngelesCaliforniaUSA
- Department of Biological ChemistryUniversity of CaliforniaLos Angeles School of MedicineLos AngelesCaliforniaUSA
| | - Michelle Carey
- UCD School of Mathematics & StatisticsUniversity College DublinDublinIreland
| | - Oliver E. Blacque
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
| | - Breandán N. Kennedy
- UCD School of Biomolecular and Biomedical ScienceUniversity College DublinDublinIreland
- UCD Conway InstituteUniversity College DublinDublinIreland
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Tmem138 is localized to the connecting cilium essential for rhodopsin localization and outer segment biogenesis. Proc Natl Acad Sci U S A 2022; 119:e2109934119. [PMID: 35394880 PMCID: PMC9169668 DOI: 10.1073/pnas.2109934119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The connecting cilium (CC) of the photoreceptor provides the only route for the trafficking of the outer segment (OS) proteins. Failure of OS protein transport causes degenerative photoreceptor diseases, including retinitis pigmentosa. We demonstrate that Tmem138, a protein linked to ciliopathy, is localized to the photoreceptor CC. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 interacts with rhodopsin and two additional CC compartment proteins, Ahi1 and Tmem231, likely forming a membrane complex to facilitate trafficking of rhodopsin and other OS-bound proteins across the CC. The study thus implicates a new line of regulation on the delivery of OS proteins through interactions with CC membrane complex(es) and provides insights into photoreceptor ciliopathy diseases. Photoreceptor connecting cilium (CC) is structurally analogous to the transition zone (TZ) of primary cilia and gates the molecular trafficking between the inner and the outer segment (OS). Retinal dystrophies with underlying CC defects are manifested in a broad array of syndromic conditions known as ciliopathies as well as nonsyndromic retinal degenerations. Despite extensive studies, many questions remain in the mechanism of protein trafficking across the photoreceptor CC. Here, we genetically inactivated mouse Tmem138, a gene encoding a putative transmembrane protein localized to the ciliary TZ and linked to ciliopathies. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 was found localized to the photoreceptor CC and was required for localization of Ahi1 to the distal subdomain of the CC. Among the examined set of OS proteins, rhodopsin was mislocalized throughout the mutant cell body prior to OS morphogenesis. Ablation of Tmem138 in mature rods recapitulated the molecular changes in the germline mutants, causing failure of disc renewal and disintegration of the OS. Furthermore, Tmem138 interacts reciprocally with rhodopsin and a related protein Tmem231, and the ciliary localization of the latter was also altered in the mutant photoreceptors. Taken together, these results suggest a crucial role of Tmem138 in the functional organization of the CC, which is essential for rhodopsin localization and OS biogenesis.
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Kanamaru T, Neuner A, Kurtulmus B, Pereira G. Balancing the length of the distal tip by septins is key for stability and signalling function of primary cilia. EMBO J 2022; 41:e108843. [PMID: 34981518 PMCID: PMC8724769 DOI: 10.15252/embj.2021108843] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/19/2021] [Accepted: 10/26/2021] [Indexed: 01/08/2023] Open
Abstract
Primary cilia are antenna-like organelles required for signalling transduction. How cilia structure is mechanistically maintained at steady-state to promote signalling is largely unknown. Here, we define that mammalian primary cilia axonemes are formed by proximal segment (PS) and distal segment (DS) delineated by tubulin polyglutamylation-rich and -poor regions, respectively. The analysis of proximal/distal segmentation indicated that perturbations leading to cilia over-elongation influenced PS or DS length with a different impact on cilia behaviour. We identified septins as novel repressors of DS growth. We show that septins control the localisation of MKS3 and CEP290 required for a functional transition zone (TZ), and the cilia tip accumulation of the microtubule-capping kinesin KIF7, a cilia-growth inhibitor. Live-cell imaging and analysis of sonic-hedgehog (SHH) signalling activation established that DS over-extension increased cilia ectocytosis events and decreased SHH activation. Our data underlines the importance of understanding cilia segmentation for length control and cilia-dependent signalling.
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Affiliation(s)
- Taishi Kanamaru
- Centre for Organismal Studies (COS)University of HeidelbergHeidelbergGermany
- German Cancer Research Centre (DKFZ)DKFZ‐ZMBH AllianceHeidelbergGermany
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
| | - Annett Neuner
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
| | - Bahtiyar Kurtulmus
- Centre for Organismal Studies (COS)University of HeidelbergHeidelbergGermany
- German Cancer Research Centre (DKFZ)DKFZ‐ZMBH AllianceHeidelbergGermany
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
| | - Gislene Pereira
- Centre for Organismal Studies (COS)University of HeidelbergHeidelbergGermany
- German Cancer Research Centre (DKFZ)DKFZ‐ZMBH AllianceHeidelbergGermany
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
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37
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Lewandowski D, Sander CL, Tworak A, Gao F, Xu Q, Skowronska-Krawczyk D. Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life. Prog Retin Eye Res 2021; 89:101037. [PMID: 34971765 PMCID: PMC10361839 DOI: 10.1016/j.preteyeres.2021.101037] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022]
Abstract
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
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Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Christopher L Sander
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Qianlan Xu
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA.
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38
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Coceres VM, Iriarte LS, Miranda-Magalhães A, Santos de Andrade TA, de Miguel N, Pereira-Neves A. Ultrastructural and Functional Analysis of a Novel Extra-Axonemal Structure in Parasitic Trichomonads. Front Cell Infect Microbiol 2021; 11:757185. [PMID: 34858875 PMCID: PMC8630684 DOI: 10.3389/fcimb.2021.757185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/19/2021] [Indexed: 12/28/2022] Open
Abstract
Trichomonas vaginalis and Tritrichomonas foetus are extracellular flagellated parasites that inhabit humans and other mammals, respectively. In addition to motility, flagella act in a variety of biological processes in different cell types, and extra-axonemal structures (EASs) have been described as fibrillar structures that provide mechanical support and act as metabolic, homeostatic, and sensory platforms in many organisms. It has been assumed that T. vaginalis and T. foetus do not have EASs. However, here, we used complementary electron microscopy techniques to reveal the ultrastructure of EASs in both parasites. Such EASs are thin filaments (3-5 nm diameter) running longitudinally along the axonemes and surrounded by the flagellar membrane, forming prominent flagellar swellings. We observed that the formation of EAS increases after parasite adhesion on the host cells, fibronectin, and precationized surfaces. A high number of rosettes, clusters of intramembrane particles that have been proposed as sensorial structures, and microvesicles protruding from the membrane were observed in the EASs. Our observations demonstrate that T. vaginalis and T. foetus can connect to themselves by EASs present in flagella. The protein VPS32, a member of the ESCRT-III complex crucial for diverse membrane remodeling events, the pinching off and release of microvesicles, was found in the surface as well as in microvesicles protruding from EASs. Moreover, we demonstrated that the formation of EAS also increases in parasites overexpressing VPS32 and that T. vaginalis-VPS32 parasites showed greater motility in semisolid agar. These results provide valuable data about the role of the flagellar EASs in the cell-to-cell communication and pathogenesis of these extracellular parasites.
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Affiliation(s)
- Veronica M Coceres
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de General San Martín (CONICET-UNSAM), Chascomús, Argentina
| | - Lucrecia S Iriarte
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de General San Martín (CONICET-UNSAM), Chascomús, Argentina
| | | | | | - Natalia de Miguel
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de General San Martín (CONICET-UNSAM), Chascomús, Argentina
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Ortin‐Martinez A, Yan NE, Tsai ELS, Comanita L, Gurdita A, Tachibana N, Liu ZC, Lu S, Dolati P, Pokrajac NT, El‐Sehemy A, Nickerson PEB, Schuurmans C, Bremner R, Wallace VA. Photoreceptor nanotubes mediate the in vivo exchange of intracellular material. EMBO J 2021; 40:e107264. [PMID: 34494680 PMCID: PMC8591540 DOI: 10.15252/embj.2020107264] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 07/15/2021] [Accepted: 07/19/2021] [Indexed: 12/17/2022] Open
Abstract
Emerging evidence suggests that intracellular molecules and organelles transfer between cells during embryonic development, tissue homeostasis and disease. We and others recently showed that transplanted and host photoreceptors engage in bidirectional transfer of intracellular material in the recipient retina, a process termed material transfer (MT). We used cell transplantation, advanced tissue imaging approaches, genetic and pharmacologic interventions and primary cell culture to characterize and elucidate the mechanism of MT. We show that MT correlates with donor cell persistence and the accumulation of donor-derived proteins, mitochondria and transcripts in acceptor cells in vivo. MT requires cell contact in vitro and is associated with the formation of stable microtubule-containing protrusions, termed photoreceptor nanotubes (Ph NTs), that connect donor and host cells in vivo and in vitro. Ph NTs mediate GFP transfer between connected cells in vitro. Furthermore, interfering with Ph NT outgrowth by targeting Rho GTPase-dependent actin remodelling inhibits MT in vivo. Collectively, our observations provide evidence for horizontal exchange of intracellular material via nanotube-like connections between neurons in vivo.
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Affiliation(s)
- Arturo Ortin‐Martinez
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
| | - Nicole E Yan
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
| | - En Leh Samuel Tsai
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
| | - Lacrimioara Comanita
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
| | - Akshay Gurdita
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
| | - Nobuhiko Tachibana
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
| | - Zhongda C Liu
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
| | - Suying Lu
- Lunenfeld Tanenbaum Research InstituteMount Sinai HospitalSinai Health SystemsTorontoONCanada
| | - Parnian Dolati
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
| | - Neno T Pokrajac
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
| | - Ahmed El‐Sehemy
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
| | - Philip E B Nickerson
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
| | - Carol Schuurmans
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
- Department of BiochemistryUniversity of TorontoTorontoONCanada
- Sunnybrook Research InstituteTorontoONCanada
- Department of Ophthalmology and Vision SciencesUniversity of TorontoTorontoONCanada
| | - Rod Bremner
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
- Lunenfeld Tanenbaum Research InstituteMount Sinai HospitalSinai Health SystemsTorontoONCanada
- Department of Ophthalmology and Vision SciencesUniversity of TorontoTorontoONCanada
| | - Valerie A Wallace
- Donald K. Johnson Eye InstituteKrembil Research InstituteUniversity Health NetworkTorontoONCanada
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
- Department of Ophthalmology and Vision SciencesUniversity of TorontoTorontoONCanada
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40
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Gabriel E, Albanna W, Pasquini G, Ramani A, Josipovic N, Mariappan A, Schinzel F, Karch CM, Bao G, Gottardo M, Suren AA, Hescheler J, Nagel-Wolfrum K, Persico V, Rizzoli SO, Altmüller J, Riparbelli MG, Callaini G, Goureau O, Papantonis A, Busskamp V, Schneider T, Gopalakrishnan J. Human brain organoids assemble functionally integrated bilateral optic vesicles. Cell Stem Cell 2021; 28:1740-1757.e8. [PMID: 34407456 DOI: 10.1016/j.stem.2021.07.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/23/2021] [Accepted: 07/20/2021] [Indexed: 02/07/2023]
Abstract
During embryogenesis, optic vesicles develop from the diencephalon via a multistep process of organogenesis. Using induced pluripotent stem cell (iPSC)-derived human brain organoids, we attempted to simplify the complexities and demonstrate formation of forebrain-associated bilateral optic vesicles, cellular diversity, and functionality. Around day 30, brain organoids attempt to assemble optic vesicles, which develop progressively as visible structures within 60 days. These optic vesicle-containing brain organoids (OVB-organoids) constitute a developing optic vesicle's cellular components, including primitive corneal epithelial and lens-like cells, retinal pigment epithelia, retinal progenitor cells, axon-like projections, and electrically active neuronal networks. OVB-organoids also display synapsin-1, CTIP-positive myelinated cortical neurons, and microglia. Interestingly, various light intensities could trigger photosensitive activity of OVB-organoids, and light sensitivities could be reset after transient photobleaching. Thus, brain organoids have the intrinsic ability to self-organize forebrain-associated primitive sensory structures in a topographically restricted manner and can allow interorgan interaction studies within a single organoid.
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Affiliation(s)
- Elke Gabriel
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Walid Albanna
- Institute for Neurophysiology, University of Cologne, 50931 Cologne, Germany; Department of Neurosurgery, RWTH Aachen University, 52074 Aachen, Germany
| | - Giovanni Pasquini
- Department of Ophthalmology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Anand Ramani
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Natasa Josipovic
- Institute of Pathology, University Medicine Göttingen, Georg-August University Göttingen, 37075 Göttingen, Germany; Center for molecular medicine, Cologne, Universität zu Köln, 50931 Köln, Germany
| | - Aruljothi Mariappan
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Friedrich Schinzel
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Celeste M Karch
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO 63116, USA
| | - Guobin Bao
- Institute of Neurophysiology and Cellular Biophysics, University Medicine Göttingen, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - Marco Gottardo
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Ata Alp Suren
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Jürgen Hescheler
- Institute for Neurophysiology, University of Cologne, 50931 Cologne, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University, 55099 Mainz, Germany
| | - Veronica Persico
- Department of Life Sciences and Medical Biotechnology University of Siena, Siena 53100, Italy
| | - Silvio O Rizzoli
- Institute of Neurophysiology and Cellular Biophysics, University Medicine Göttingen, Georg-August-Universität Göttingen, 37073 Göttingen, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), Universität zu Köln, Köln, Germany; Center for molecular medicine, Cologne, Universität zu Köln, 50931 Köln, Germany
| | | | - Giuliano Callaini
- Department of Life Sciences and Medical Biotechnology University of Siena, Siena 53100, Italy
| | - Olivier Goureau
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 75012 Paris, France
| | - Argyris Papantonis
- Institute of Pathology, University Medicine Göttingen, Georg-August University Göttingen, 37075 Göttingen, Germany
| | - Volker Busskamp
- Department of Ophthalmology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Toni Schneider
- Institute for Neurophysiology, University of Cologne, 50931 Cologne, Germany
| | - Jay Gopalakrishnan
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany.
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Bardet-Biedl syndrome proteins modulate the release of bioactive extracellular vesicles. Nat Commun 2021; 12:5671. [PMID: 34580290 PMCID: PMC8476602 DOI: 10.1038/s41467-021-25929-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/07/2021] [Indexed: 12/19/2022] Open
Abstract
Primary cilia are microtubule based sensory organelles important for receiving and processing cellular signals. Recent studies have shown that cilia also release extracellular vesicles (EVs). Because EVs have been shown to exert various physiological functions, these findings have the potential to alter our understanding of how primary cilia regulate specific signalling pathways. So far the focus has been on lgEVs budding directly from the ciliary membrane. An association between cilia and MVB-derived smEVs has not yet been described. We show that ciliary mutant mammalian cells demonstrate increased secretion of small EVs (smEVs) and a change in EV composition. Characterisation of smEV cargo identified signalling molecules that are differentially loaded upon ciliary dysfunction. Furthermore, we show that these smEVs are biologically active and modulate the WNT response in recipient cells. These results provide us with insights into smEV-dependent ciliary signalling mechanisms which might underly ciliopathy disease pathogenesis. Extracellular vesicles (EV) are known to be released from the primary cilium, but the role ciliary proteins play in EV biogenesis remains unexplored. Here, the authors demonstrate increased secretion of small EVs with altered cargo composition from cells with known ciliarelated mutations. Wnt related molecules made up a majority of altered cargo
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Razzauti A, Laurent P. Ectocytosis prevents accumulation of ciliary cargo in C. elegans sensory neurons. eLife 2021; 10:67670. [PMID: 34533135 PMCID: PMC8492061 DOI: 10.7554/elife.67670] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 09/16/2021] [Indexed: 12/13/2022] Open
Abstract
Cilia are sensory organelles protruding from cell surfaces. Release of extracellular vesicles (EVs) from cilia was previously observed in mammals, Chlamydomonas, and in male Caenorhabditis elegans. Using the EV marker TSP-6 (an ortholog of mammalian CD9) and other ciliary receptors, we show that EVs are formed from ciliated sensory neurons in C. elegans hermaphrodites. Release of EVs is observed from two ciliary locations: the cilia tip and/or periciliary membrane compartment (PCMC). Outward budding of EVs from the cilia tip leads to their release into the environment. EVs' budding from the PCMC is concomitantly phagocytosed by the associated glial cells. To maintain cilia composition, a tight regulation of cargo import and removal is achieved by the action of intra-flagellar transport (IFT). Unbalanced IFT due to cargo overexpression or mutations in the IFT machinery leads to local accumulation of ciliary proteins. Disposal of excess ciliary proteins via EVs reduces their local accumulation and exports them to the environment and/or to the glia associated to these ciliated neurons. We suggest that EV budding from cilia subcompartments acts as a safeguard mechanism to remove deleterious excess of ciliary material.
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Affiliation(s)
- Adria Razzauti
- Laboratory of Neurophysiology, ULB Neuroscience Institute (UNI), Université Libre de Bruxelles(ULB), Brussels, Belgium
| | - Patrick Laurent
- Laboratory of Neurophysiology, ULB Neuroscience Institute (UNI), Université Libre de Bruxelles(ULB), Brussels, Belgium
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Wang J, Nikonorova IA, Silva M, Walsh JD, Tilton PE, Gu A, Akella JS, Barr MM. Sensory cilia act as a specialized venue for regulated extracellular vesicle biogenesis and signaling. Curr Biol 2021; 31:3943-3951.e3. [PMID: 34270950 DOI: 10.1016/j.cub.2021.06.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/30/2021] [Accepted: 06/14/2021] [Indexed: 02/07/2023]
Abstract
Ciliary extracellular vesicle (EV) shedding is evolutionarily conserved. In Chlamydomonas and C. elegans, ciliary EVs act as signaling devices.1-3 In cultured mammalian cells, ciliary EVs regulate ciliary disposal but also receptor abundance and signaling, ciliary length, and ciliary membrane dynamics.4-7 Mammalian cilia produce EVs from the tip and along the ciliary membrane.8,9 This study aimed to determine the functional significance of shedding at distinct locations and to explore ciliary EV biogenesis mechanisms. Using Airyscan super-resolution imaging in living C. elegans animals, we find that neuronal sensory cilia shed TRP polycystin-2 channel PKD-2::GFP-carrying EVs from two distinct sites: the ciliary tip and the ciliary base. Ciliary tip shedding requires distal ciliary enrichment of PKD-2 by the myristoylated coiled-coil protein CIL-7. Kinesin-3 KLP-6 and intraflagellar transport (IFT) kinesin-2 motors are also required for ciliary tip EV shedding. A big unanswered question in the EV field is how cells sort EV cargo. Here, we show that two EV cargoes- CIL-7 and PKD-2-localized and trafficked differently along cilia and were sorted to different environmentally released EVs. In response to mating partners, C. elegans males modulate EV cargo composition by increasing the ratio of PKD-2 to CIL-7 EVs. Overall, our study indicates that the cilium and its trafficking machinery act as a specialized venue for regulated EV biogenesis and signaling.
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Affiliation(s)
- Juan Wang
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
| | - Inna A Nikonorova
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Malan Silva
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Jonathon D Walsh
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Peter E Tilton
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Amanda Gu
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Jyothi S Akella
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Maureen M Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
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Ikegami K, Ijaz F. Current understandings of the relationship between extracellular vesicles and cilia. J Biochem 2021; 169:139-145. [PMID: 33035312 DOI: 10.1093/jb/mvaa112] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 09/19/2020] [Indexed: 12/16/2022] Open
Abstract
Mammalian cells have a tiny hair-like protrusion on their surface called a primary cilium. Primary cilia are thought to be the antennae for the cells, receiving signals from the environment. In some studies, extracellular vesicles (EVs) were found attached to the surface of the primary cilium. An idea for the phenomenon is that the primary cilium is the receptor for receiving the EVs. Meanwhile, a unicellular organism, Chlamydomonas, which has two long cilia, usually called flagella, release EVs termed ectosomes from the surface of the flagella. Accumulating evidence suggests that the primary cilium also functions as the 'emitter' of EVs. Physiological and pathological impacts are also elucidated for the release of EVs from primary cilia. However, the roles of released cilia-derived EVs remain to be clarified. This review introduces the historical background of the relationship between EVs and cilia, and recent progresses in the research field.
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Affiliation(s)
- Koji Ikegami
- Department of Anatomy and Developmental Biology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Hiroshima 734-8553, Japan; and.,Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi 332-0012, Japan
| | - Faryal Ijaz
- Department of Anatomy and Developmental Biology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Hiroshima 734-8553, Japan; and
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Rohrer B, Biswal MR, Obert E, Dang Y, Su Y, Zuo X, Fogelgren B, Kondkar AA, Lobo GP, Lipschutz JH. Conditional Loss of the Exocyst Component Exoc5 in Retinal Pigment Epithelium (RPE) Results in RPE Dysfunction, Photoreceptor Cell Degeneration, and Decreased Visual Function. Int J Mol Sci 2021; 22:5083. [PMID: 34064901 PMCID: PMC8151988 DOI: 10.3390/ijms22105083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/29/2021] [Accepted: 05/07/2021] [Indexed: 11/17/2022] Open
Abstract
To characterize the mechanisms by which the highly conserved exocyst trafficking complex regulates eye physiology in zebrafish and mice, we focused on Exoc5 (also known as sec10), a central exocyst component. We analyzed both exoc5 zebrafish mutants and retinal pigmented epithelium (RPE)-specific Exoc5 knockout mice. Exoc5 is present in both the non-pigmented epithelium of the ciliary body and in the RPE. In this study, we set out to establish an animal model to study the mechanisms underlying the ocular phenotype and to establish if loss of visual function is induced by postnatal RPE Exoc5-deficiency. Exoc5-/- zebrafish had smaller eyes, with decreased number of melanocytes in the RPE and shorter photoreceptor outer segments. At 3.5 days post-fertilization, loss of rod and cone opsins were observed in zebrafish exoc5 mutants. Mice with postnatal RPE-specific loss of Exoc5 showed retinal thinning associated with compromised visual function and loss of visual photoreceptor pigments. Abnormal levels of RPE65 together with a reduced c-wave amplitude indicate a dysfunctional RPE. The retinal phenotype in Exoc5-/- mice was present at 20 weeks, but was more pronounced at 27 weeks, indicating progressive disease phenotype. We previously showed that the exocyst is necessary for photoreceptor ciliogenesis and retinal development. Here, we report that exoc5 mutant zebrafish and mice with RPE-specific genetic ablation of Exoc5 develop abnormal RPE pigmentation, resulting in retinal cell dystrophy and loss of visual pigments associated with compromised vision. Together, these data suggest that exocyst-mediated signaling in the RPE is required for RPE structure and function, indirectly leading to photoreceptor degeneration.
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Affiliation(s)
- Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA; (B.R.); (E.O.)
- Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
| | - Manas R. Biswal
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA;
| | - Elisabeth Obert
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA; (B.R.); (E.O.)
| | - Yujing Dang
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
| | - Yanhui Su
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
| | - Xiaofeng Zuo
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
| | - Ben Fogelgren
- Department of Anatomy, Biochemistry, and Physiology, University of Hawaii at Manoa, Honolulu, HI 96813, USA;
| | - Altaf A. Kondkar
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh 11411, Saudi Arabia;
| | - Glenn P. Lobo
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA; (B.R.); (E.O.)
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
- Department of Ophthalmology and Visual Neurosciences, Lions Research Building, 2001 6th Street SE., Room 225, University of Minnesota, Minneapolis, MN 55455, USA
| | - Joshua H. Lipschutz
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; (Y.D.); (Y.S.); (X.Z.); (J.H.L.)
- Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29425, USA
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Völkner M, Kurth T, Schor J, Ebner LJA, Bardtke L, Kavak C, Hackermüller J, Karl MO. Mouse Retinal Organoid Growth and Maintenance in Longer-Term Culture. Front Cell Dev Biol 2021; 9:645704. [PMID: 33996806 PMCID: PMC8114082 DOI: 10.3389/fcell.2021.645704] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/11/2021] [Indexed: 12/14/2022] Open
Abstract
Using retinal organoid systems, organ-like 3D tissues, relies implicitly on their robustness. However, essential key parameters, particularly retinal growth and longer-term culture, are still insufficiently defined. Here, we hypothesize that a previously optimized protocol for high yield of evenly-sized mouse retinal organoids with low variability facilitates assessment of such parameters. We demonstrate that these organoids reliably complete retinogenesis, and can be maintained at least up to 60 days in culture. During this time, the organoids continue to mature on a molecular and (ultra)structural level: They develop photoreceptor outer segments and synapses, transiently maintain its cell composition for about 5-10 days after completing retinogenesis, and subsequently develop pathologic changes - mainly of the inner but also outer retina and reactive gliosis. To test whether this organoid system provides experimental access to the retina during and upon completion of development, we defined and stimulated organoid growth by activating sonic hedgehog signaling, which in patients and mice in vivo with a congenital defect leads to enlarged eyes. Here, a sonic hedgehog signaling activator increased retinal epithelia length in the organoid system when applied during but not after completion of development. This experimentally supports organoid maturation, stability, and experimental reproducibility in this organoid system, and provides a potential enlarged retina pathology model, as well as a protocol for producing larger organoids. Together, our study advances the understanding of retinal growth, maturation, and maintenance, and further optimizes the organoid system for future utilization.
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Affiliation(s)
- Manuela Völkner
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Thomas Kurth
- Center for Molecular and Cellular Bioengineering, Technology Platform, Electron Microscopy and Histology Facility, Technische Universität Dresden, Dresden, Germany
| | - Jana Schor
- Young Investigators Group Bioinformatics and Transcriptomics, Department Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Lynn J A Ebner
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Lara Bardtke
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Cagri Kavak
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Jörg Hackermüller
- Young Investigators Group Bioinformatics and Transcriptomics, Department Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Mike O Karl
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany.,CRTD - Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
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Lewis TR, Makia MS, Castillo CM, Al-Ubaidi MR, Naash MI, Arshavsky VY. Photoreceptor Disc Enclosure Is Tightly Controlled by Peripherin-2 Oligomerization. J Neurosci 2021; 41:3588-3596. [PMID: 33707293 PMCID: PMC8055076 DOI: 10.1523/jneurosci.0041-21.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/15/2021] [Accepted: 03/05/2021] [Indexed: 11/21/2022] Open
Abstract
Mutations in the PRPH2 gene encoding the photoreceptor-specific protein PRPH2 (also known as peripherin-2 or rds) cause a broad range of autosomal dominant retinal diseases. Most of these mutations affect the structure of the light-sensitive photoreceptor outer segment, which is composed of a stack of flattened "disc" membranes surrounded by the plasma membrane. The outer segment is renewed on a daily basis in a process whereby new discs are added at the outer segment base and old discs are shed at the outer segment tip. New discs are formed as serial membrane evaginations, which eventually enclose through a complex process of membrane remodeling (completely in rods and partially in cones). As disc enclosure proceeds, PRPH2 localizes to the rims of enclosed discs where it forms oligomers which fortify the highly curved membrane structure of these rims. In this study, we analyzed the outer segment phenotypes of mice of both sexes bearing a single copy of either the C150S or the Y141C PRPH2 mutation known to prevent or increase the degree of PRPH2 oligomerization, respectively. Strikingly, both mutations increased the number of newly forming, not-yet-enclosed discs, indicating that the precision of disc enclosure is regulated by PRPH2 oligomerization. Without tightly controlled enclosure, discs occasionally over-elongate and form large membranous "whorls" instead of disc stacks. These data show that the defects in outer segment structure arising from abnormal PRPH2 oligomerization are manifested at the stage of disc enclosure.SIGNIFICANCE STATEMENT The light-sensitive photoreceptor outer segment contains a stack of flattened "disc" membranes that are surrounded, or "enclosed," by the outer segment membrane. Disc enclosure is an adaptation increasing photoreceptor light sensitivity by facilitating the diffusion of the second messenger along the outer segment axes. However, the molecular mechanisms by which photoreceptor discs enclose within the outer segment membrane remain poorly understood. We now demonstrate that oligomers of the photoreceptor-specific protein peripherin-2, or PRPH2, play an active role in this process. We further propose that defects in disc enclosure because of abnormal PRPH2 oligomerization result in major structural abnormalities of the outer segment, ultimately leading to loss of visual function and cell degeneration in PRPH2 mutant models and human patients.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
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48
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Functional compartmentalization of photoreceptor neurons. Pflugers Arch 2021; 473:1493-1516. [PMID: 33880652 DOI: 10.1007/s00424-021-02558-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 12/16/2022]
Abstract
Retinal photoreceptors are neurons that convert dynamically changing patterns of light into electrical signals that are processed by retinal interneurons and ultimately transmitted to vision centers in the brain. They represent the essential first step in seeing without which the remainder of the visual system is rendered moot. To support this role, the major functions of photoreceptors are segregated into three main specialized compartments-the outer segment, the inner segment, and the pre-synaptic terminal. This compartmentalization is crucial for photoreceptor function-disruption leads to devastating blinding diseases for which therapies remain elusive. In this review, we examine the current understanding of the molecular and physical mechanisms underlying photoreceptor functional compartmentalization and highlight areas where significant knowledge gaps remain.
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The GARP Domain of the Rod CNG Channel's β1-Subunit Contains Distinct Sites for Outer Segment Targeting and Connecting to the Photoreceptor Disk Rim. J Neurosci 2021; 41:3094-3104. [PMID: 33637563 DOI: 10.1523/jneurosci.2609-20.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/15/2021] [Accepted: 02/18/2021] [Indexed: 11/21/2022] Open
Abstract
Vision begins when light is captured by the outer segment organelle of photoreceptor cells in the retina. Outer segments are modified cilia filled with hundreds of flattened disk-shaped membranes. Disk membranes are separated from the surrounding plasma membrane, and each membrane type has unique protein components. The mechanisms underlying this protein sorting remain entirely unknown. In this study, we investigated the outer segment delivery of the rod cyclic nucleotide-gated (CNG) channel, which is located in the outer segment plasma membrane, where it mediates the electrical response to light. Using Xenopus and mouse models of both sexes, we now show that the targeted delivery of the CNG channel to the outer segment uses the conventional secretory pathway, including protein processing in both ER and Golgi, and requires preassembly of its constituent α1 and β1 subunits. We further demonstrate that the N-terminal glutamic acid-rich protein (GARP) domain of CNGβ1 contains two distinct functional regions. The glutamic acid-rich region encodes specific information targeting the channel to rod outer segments. The adjacent proline-enriched region connects the CNG channel to photoreceptor disk rims, likely through an interaction with peripherin-2. These data reveal fine functional specializations within the structural domains of the CNG channel and suggest that its sequestration to the outer segment plasma membrane requires an interaction with peripherin-2.SIGNIFICANCE STATEMENT Neurons and other differentiated cells have a remarkable ability to deliver and organize signaling proteins at precise subcellular locations. We now report that the CNG channel, mediating the electrical response to light in rod photoreceptors, contains two specialized regions within the N terminus of its β-subunit: one responsible for delivery of this channel to the ciliary outer segment organelle and another for subsequent channel sequestration into the outer segment plasma membrane. These findings expand our understanding of the molecular specializations used by neurons to populate their critical functional compartments.
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50
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Fang X, Peden AA, van Eeden FJM, Malicki JJ. Identification of additional outer segment targeting signals in zebrafish rod opsin. J Cell Sci 2021; 134:jcs.254995. [PMID: 33589494 DOI: 10.1242/jcs.254995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/01/2021] [Indexed: 11/20/2022] Open
Abstract
In vertebrate photoreceptors, opsins are highly concentrated in a morphologically distinct ciliary compartment known as the outer segment (OS). Opsin is synthesized in the cell body and transported to the OS at a remarkable rate of 100 to 1000 molecules per second. Opsin transport defects contribute to photoreceptor loss and blindness in human ciliopathies. Previous studies revealed that the rhodopsin C-terminal tail, of 44 amino acids, is sufficient to mediate OS targeting in Xenopus photoreceptors. Here, we show that, although the Xenopus C-terminus retains this function in zebrafish, the homologous zebrafish sequence is not sufficient to target opsin to the OS. This functional difference is largely caused by a change of a single amino acid present in Xenopus but not in other vertebrates examined. Furthermore, we find that sequences in the third intracellular cytoplasmic loop (IC3) and adjacent regions of transmembrane helices 6 and 7 are also necessary for opsin transport in zebrafish. Combined with the cytoplasmic tail, these sequences are sufficient to target opsin to the ciliary compartment.
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Affiliation(s)
- Xiaoming Fang
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Andrew A Peden
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Fredericus J M van Eeden
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Jarema J Malicki
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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