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Liu X, Pacwa A, Bresciani G, Swierczynska M, Dorecka M, Smedowski A. Retinal primary cilia and their dysfunction in retinal neurodegenerative diseases: beyond ciliopathies. Mol Med 2024; 30:109. [PMID: 39060957 PMCID: PMC11282803 DOI: 10.1186/s10020-024-00875-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 07/13/2024] [Indexed: 07/28/2024] Open
Abstract
Primary cilia are sensory organelles that extend from the cellular membrane and are found in a wide range of cell types. Cilia possess a plethora of vital components that enable the detection and transmission of several signaling pathways, including Wnt and Shh. In turn, the regulation of ciliogenesis and cilium length is influenced by various factors, including autophagy, organization of the actin cytoskeleton, and signaling inside the cilium. Irregularities in the development, maintenance, and function of this cellular component lead to a range of clinical manifestations known as ciliopathies. The majority of people with ciliopathies have a high prevalence of retinal degeneration. The most common theory is that retinal degeneration is primarily caused by functional and developmental problems within retinal photoreceptors. The contribution of other ciliated retinal cell types to retinal degeneration has not been explored to date. In this review, we examine the occurrence of primary cilia in various retinal cell types and their significance in pathology. Additionally, we explore potential therapeutic approaches targeting ciliopathies. By engaging in this endeavor, we present new ideas that elucidate innovative concepts for the future investigation and treatment of retinal ciliopathies.
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Affiliation(s)
- Xiaonan Liu
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Ceglana 35, 40-514, Katowice, Poland.
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland.
| | - Anna Pacwa
- GlaucoTech Co, Katowice, Poland
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medykow 18, 40-752, Katowice, Poland
| | | | - Marta Swierczynska
- Department of Ophthalmology, Professor K. Gibinski University Clinical Center, Medical University of Silesia, Katowice, Poland
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Ceglana 35, 40-514, Katowice, Poland
| | - Mariola Dorecka
- Department of Ophthalmology, Professor K. Gibinski University Clinical Center, Medical University of Silesia, Katowice, Poland
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Ceglana 35, 40-514, Katowice, Poland
| | - Adrian Smedowski
- GlaucoTech Co, Katowice, Poland.
- Department of Ophthalmology, Professor K. Gibinski University Clinical Center, Medical University of Silesia, Katowice, Poland.
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Ceglana 35, 40-514, Katowice, Poland.
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Du X, Butler AG, Chen HY. Cell-cell interaction in the pathogenesis of inherited retinal diseases. Front Cell Dev Biol 2024; 12:1332944. [PMID: 38500685 PMCID: PMC10944940 DOI: 10.3389/fcell.2024.1332944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/06/2024] [Indexed: 03/20/2024] Open
Abstract
The retina is part of the central nervous system specialized for vision. Inherited retinal diseases (IRD) are a group of clinically and genetically heterogenous disorders that lead to progressive vision impairment or blindness. Although each disorder is rare, IRD accumulatively cause blindness in up to 5.5 million individuals worldwide. Currently, the pathophysiological mechanisms of IRD are not fully understood and there are limited treatment options available. Most IRD are caused by degeneration of light-sensitive photoreceptors. Genetic mutations that abrogate the structure and/or function of photoreceptors lead to visual impairment followed by blindness caused by loss of photoreceptors. In healthy retina, photoreceptors structurally and functionally interact with retinal pigment epithelium (RPE) and Müller glia (MG) to maintain retinal homeostasis. Multiple IRD with photoreceptor degeneration as a major phenotype are caused by mutations of RPE- and/or MG-associated genes. Recent studies also reveal compromised MG and RPE caused by mutations in ubiquitously expressed ciliary genes. Therefore, photoreceptor degeneration could be a direct consequence of gene mutations and/or could be secondary to the dysfunction of their interaction partners in the retina. This review summarizes the mechanisms of photoreceptor-RPE/MG interaction in supporting retinal functions and discusses how the disruption of these processes could lead to photoreceptor degeneration, with an aim to provide a unique perspective of IRD pathogenesis and treatment paradigm. We will first describe the biology of retina and IRD and then discuss the interaction between photoreceptors and MG/RPE as well as their implications in disease pathogenesis. Finally, we will summarize the recent advances in IRD therapeutics targeting MG and/or RPE.
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Affiliation(s)
| | | | - Holly Y. Chen
- Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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3
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Delvallée C, Dollfus H. Retinal Degeneration Animal Models in Bardet-Biedl Syndrome and Related Ciliopathies. Cold Spring Harb Perspect Med 2023; 13:13/1/a041303. [PMID: 36596648 PMCID: PMC9808547 DOI: 10.1101/cshperspect.a041303] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Retinal degeneration due to photoreceptor ciliary-related proteins dysfunction accounts for more than 25% of all inherited retinal dystrophies. The cilium, being an evolutionarily conserved and ubiquitous organelle implied in many cellular functions, can be investigated by way of many models from invertebrate models to nonhuman primates, all these models have massively contributed to the pathogenesis understanding of human ciliopathies. Taking the Bardet-Biedl syndrome (BBS) as an emblematic example as well as other related syndromic ciliopathies, the contribution of a wide range of models has enabled to characterize the role of the BBS proteins in the archetypical cilium but also at the level of the connecting cilium of the photoreceptors. There are more than 24 BBS genes encoding for proteins that form different complexes such as the BBSome and the chaperone proteins complex. But how they lead to retinal degeneration remains a matter of debate with the possible accumulation of proteins in the inner segment and/or accumulation of unwanted proteins in the outer segment that cannot return in the inner segment machinery. Many BBS proteins (but not the chaperonins for instance) can be modeled in primitive organisms such as Paramecium, Chlamydomonas reinardtii, Trypanosoma brucei, and Caenorhabditis elegans These models have enabled clarifying the role of a subset of BBS proteins in the primary cilium as well as their relations with other modules such as the intraflagellar transport (IFT) module, the nephronophthisis (NPHP) module, or the Meckel-Gruber syndrome (MKS)/Joubert syndrome (JBTS) module mostly involved with the transition zone of the primary cilia. Assessing the role of the primary cilia structure of the connecting cilium of the photoreceptor cells has been very much studied by way of zebrafish modeling (Danio rerio) as well as by a plethora of mouse models. More recently, large animal models have been described for three BBS genes and one nonhuman primate model in rhesus macaque for BBS7 In completion to animal models, human cell models can now be used notably thanks to gene editing and the use of induced pluripotent stem cells (iPSCs). All these models are not only important for pathogenesis understanding but also very useful for studying therapeutic avenues, their pros and cons, especially for gene replacement therapy as well as pharmacological triggers.
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Affiliation(s)
- Clarisse Delvallée
- Laboratoire de Génétique Médicale UMRS1112, Centre de Recherche Biomédicale de Strasbourg, CRBS, Institut de Génétique Médicale d'Alsace, IGMA, Strasbourg 67000, France
| | - Hélène Dollfus
- Laboratoire de Génétique Médicale UMRS1112, Centre de Recherche Biomédicale de Strasbourg, CRBS, Institut de Génétique Médicale d'Alsace, IGMA, Strasbourg 67000, France
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4
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Guo DF, Merrill RA, Qian L, Hsu Y, Zhang Q, Lin Z, Thedens DR, Usachev YM, Grumbach I, Sheffield VC, Strack S, Rahmouni K. The BBSome regulates mitochondria dynamics and function. Mol Metab 2023; 67:101654. [PMID: 36513220 PMCID: PMC9792363 DOI: 10.1016/j.molmet.2022.101654] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE The essential role of mitochondria in regulation of metabolic function and other physiological processes has garnered enormous interest in understanding the mechanisms controlling the function of this organelle. We assessed the role of the BBSome, a protein complex composed of eight Bardet-Biedl syndrome (BBS) proteins, in the control of mitochondria dynamic and function. METHODS We used a multidisciplinary approach that include CRISPR/Cas9 technology-mediated generation of a stable Bbs1 gene knockout hypothalamic N39 neuronal cell line. We also analyzed the phenotype of BBSome deficient mice in presence or absence of the gene encoding A-kinase anchoring protein 1 (AKAP1). RESULTS Our data show that the BBSome play an important role in the regulation of mitochondria dynamics and function. Disruption of the BBSome cause mitochondria hyperfusion in cell lines, fibroblasts derived from patients as well as in hypothalamic neurons and brown adipocytes of mice. The morphological changes in mitochondria translate into functional abnormalities as indicated by the reduced oxygen consumption rate and altered mitochondrial distribution and calcium handling. Mechanistically, we demonstrate that the BBSome modulates the activity of dynamin-like protein 1 (DRP1), a key regulator of mitochondrial fission, by regulating its phosphorylation and translocation to the mitochondria. Notably, rescuing the decrease in DRP1 activity through deletion of one copy of the gene encoding AKAP1 was effective to normalize the defects in mitochondrial morphology and activity induced by BBSome deficiency. Importantly, this was associated with improvement in several of the phenotypes caused by loss of the BBSome such as the neuroanatomical abnormalities, metabolic alterations and obesity highlighting the importance of mitochondria defects in the pathophysiology of BBS. CONCLUSIONS These findings demonstrate a critical role of the BBSome in the modulation of mitochondria function and point to mitochondrial defects as a key disease mechanism in BBS.
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Affiliation(s)
- Deng-Fu Guo
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Veterans Affairs Health Care System, Iowa City, IA, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Lan Qian
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Ying Hsu
- Veterans Affairs Health Care System, Iowa City, IA, USA
| | - Qihong Zhang
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Zhihong Lin
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Daniel R Thedens
- Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Yuriy M Usachev
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Isabella Grumbach
- Veterans Affairs Health Care System, Iowa City, IA, USA; Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Val C Sheffield
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Veterans Affairs Health Care System, Iowa City, IA, USA; Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
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Bassetto M, Ajoy D, Poulhes F, Obringer C, Walter A, Messadeq N, Sadeghi A, Puranen J, Ruponen M, Kettunen M, Toropainen E, Urtti A, Dollfus H, Zelphati O, Marion V. Magnetically Assisted Drug Delivery of Topical Eye Drops Maintains Retinal Function In Vivo in Mice. Pharmaceutics 2021; 13:pharmaceutics13101650. [PMID: 34683941 PMCID: PMC8540400 DOI: 10.3390/pharmaceutics13101650] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/24/2021] [Accepted: 09/29/2021] [Indexed: 01/21/2023] Open
Abstract
Barded-Biedl syndrome (BBS) is a rare genetic disorder with an unmet medical need for retinal degeneration. Small-molecule drugs were previously identified to slow down the apoptosis of photoreceptors in BBS mouse models. Clinical translation was not practical due to the necessity of repetitive invasive intravitreal injections for pediatric populations. Non-invasive methods of retinal drug targeting are a prerequisite for acceptable adaptation to the targeted pediatric patient population. Here, we present the development and functional testing of a non-invasive, topical, magnetically assisted delivery system, harnessing the ability of magnetic nanoparticles (MNPs) to cargo two drugs (guanabenz and valproic acid) with anti-unfolded protein response (UPR) properties towards the retina. Using magnetic resonance imaging (MRI), we showed the MNPs' presence in the retina of Bbs wild-type mice, and their photoreceptor localization was validated using transmission electron microscopy (TEM). Subsequent electroretinogram recordings (ERGs) demonstrated that we achieved beneficial biological effects with the magnetically assisted treatment translating the maintained light detection in Bbs-/- mice (KO). To our knowledge, this is the first demonstration of efficient magnetic drug targeting in the photoreceptors in vivo after topical administration. This non-invasive, needle-free technology expands the application of SMDs for the treatment of a vast spectrum of retinal degenerations and other ocular diseases.
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Affiliation(s)
- Marco Bassetto
- OZ Biosciences, Parc Scientifique de Luminy, Case 922, Zone Entreprise, CEDEX 9, 13288 Marseille, France; (M.B.); (F.P.); (A.W.)
| | - Daniel Ajoy
- INSERM, Ciliopathies Modeling and Associated Therapies Group, Laboratoire de Génétique Médicale, UMRS_U1112, Fédération de Médicine Translationelle de Strasbourg, Université de Strasbourg, 67085 Strasbourg, France; (D.A.); (C.O.); (H.D.)
| | - Florent Poulhes
- OZ Biosciences, Parc Scientifique de Luminy, Case 922, Zone Entreprise, CEDEX 9, 13288 Marseille, France; (M.B.); (F.P.); (A.W.)
| | - Cathy Obringer
- INSERM, Ciliopathies Modeling and Associated Therapies Group, Laboratoire de Génétique Médicale, UMRS_U1112, Fédération de Médicine Translationelle de Strasbourg, Université de Strasbourg, 67085 Strasbourg, France; (D.A.); (C.O.); (H.D.)
| | - Aurelie Walter
- OZ Biosciences, Parc Scientifique de Luminy, Case 922, Zone Entreprise, CEDEX 9, 13288 Marseille, France; (M.B.); (F.P.); (A.W.)
| | - Nadia Messadeq
- INSERM, Institute of Genetics and Molecular and Cellular Biology (IGBMC), 67640 Illkrich-Graffenstaden, France;
| | - Amir Sadeghi
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland; (A.S.); (J.P.); (M.R.); (E.T.); (A.U.)
| | - Jooseppi Puranen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland; (A.S.); (J.P.); (M.R.); (E.T.); (A.U.)
| | - Marika Ruponen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland; (A.S.); (J.P.); (M.R.); (E.T.); (A.U.)
| | - Mikko Kettunen
- Kuopio Biomedical Imaging Unit, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70150 Kuopio, Finland;
| | - Elisa Toropainen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland; (A.S.); (J.P.); (M.R.); (E.T.); (A.U.)
| | - Arto Urtti
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland; (A.S.); (J.P.); (M.R.); (E.T.); (A.U.)
| | - Hélène Dollfus
- INSERM, Ciliopathies Modeling and Associated Therapies Group, Laboratoire de Génétique Médicale, UMRS_U1112, Fédération de Médicine Translationelle de Strasbourg, Université de Strasbourg, 67085 Strasbourg, France; (D.A.); (C.O.); (H.D.)
- Laboratoire de Génétique Médicale, UMRS_U1112, Institut de Génétique Médicale d’Alsace, Fédération de Médicine Translationelle de Strasbourg, Hopiaux Universitaires de Strasbourg, Université de Strasbourg, 67085 Strasbourg, France
| | - Olivier Zelphati
- OZ Biosciences, Parc Scientifique de Luminy, Case 922, Zone Entreprise, CEDEX 9, 13288 Marseille, France; (M.B.); (F.P.); (A.W.)
- Correspondence: (O.Z.); or (V.M.)
| | - Vincent Marion
- INSERM, Ciliopathies Modeling and Associated Therapies Group, Laboratoire de Génétique Médicale, UMRS_U1112, Fédération de Médicine Translationelle de Strasbourg, Université de Strasbourg, 67085 Strasbourg, France; (D.A.); (C.O.); (H.D.)
- ALMS Therapeutics, Parc d’Innovation, 650 Boulevard Gonthier d’Andernach, 67400 Illkirch-Graffenstaden, France
- Correspondence: (O.Z.); or (V.M.)
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6
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Bassetto M, Sen M, Poulhes F, Arango-Gonzalez B, Bonvin E, Sapet C, Ueffing M, Zelphati O. New Method for Efficient siRNA Delivery in Retina Explants: Reverse Magnetofection. Bioconjug Chem 2021; 32:1078-1093. [PMID: 34081855 DOI: 10.1021/acs.bioconjchem.1c00132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The prevalence of retinal disorders associated with visual impairment and blindness is increasing worldwide, while most of them remain without effective treatment. Pharmacological and molecular therapy development is hampered by the lack of effective drug delivery into the posterior segment of the eye. Among molecular approaches, RNA-interference (RNAi) features strong advantages, yet delivering it to the inner layer of the retina appears extremely challenging. To address this, we developed an original magnetic nanoparticles (MNPs)-based transfection method that allows the efficient delivery of siRNA in all retinal layers of rat adult retinas through magnetic targeting. To establish delivery of RNAi throughout the retina, we have chosen organotypic retinal explants as an ex vivo model and for future high content screening of molecular drugs. Conversely to classic Magnetofection, and similar to conditions in the posterior chamber of the eye, our methods allows attraction of siRNA complexed to MNPs from the culture media into the explant. Our method termed "Reverse Magnetofection" provides a novel and nontoxic strategy for RNAi-based molecular as well as gene therapy in the retina that can be transferred to a wide variety of organ explants.
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Affiliation(s)
- Marco Bassetto
- OZ Biosciences, Parc scientifique de Luminy, Case 922, zone entreprise, 13288 Marseille, France
| | - Merve Sen
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - Florent Poulhes
- OZ Biosciences, Parc scientifique de Luminy, Case 922, zone entreprise, 13288 Marseille, France
| | - Blanca Arango-Gonzalez
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - Elise Bonvin
- OZ Biosciences, Parc scientifique de Luminy, Case 922, zone entreprise, 13288 Marseille, France
| | - Cedric Sapet
- OZ Biosciences, Parc scientifique de Luminy, Case 922, zone entreprise, 13288 Marseille, France
| | - Marius Ueffing
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - Olivier Zelphati
- OZ Biosciences, Parc scientifique de Luminy, Case 922, zone entreprise, 13288 Marseille, France
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Chen HY, Lehmann OJ, Swaroop A. Genetics and therapy for pediatric eye diseases. EBioMedicine 2021; 67:103360. [PMID: 33975254 PMCID: PMC8122153 DOI: 10.1016/j.ebiom.2021.103360] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/29/2021] [Accepted: 04/12/2021] [Indexed: 12/26/2022] Open
Abstract
Ocular morphogenesis in vertebrates is a highly organized process, orchestrated largely by intrinsic genetic programs that exhibit stringent spatiotemporal control. Alternations in these genetic instructions can lead to hereditary or nonhereditary congenital disorders, a major cause of childhood visual impairment, and contribute to common late-onset blinding diseases. Currently, limited treatment options exist for clinical phenotypes involving eye development. This review summarizes recent advances in our understanding of early-onset ocular disorders and highlights genetic complexities in development and diseases, specifically focusing on coloboma, congenital glaucoma and Leber congenital amaurosis. We also discuss innovative paradigms for potential therapeutic modalities.
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Affiliation(s)
- Holly Y Chen
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892 USA.
| | - Ordan J Lehmann
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada; Department of Medical Genetics, University of Alberta, Edmonton, Canada.
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892 USA.
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Aleman TS, O'Neil EC, O'Connor K, Jiang YY, Aleman IA, Bennett J, Morgan JIW, Toussaint BW. Bardet-Biedl syndrome-7 ( BBS7) shows treatment potential and a cone-rod dystrophy phenotype that recapitulates the non-human primate model. Ophthalmic Genet 2021; 42:252-265. [PMID: 33729075 DOI: 10.1080/13816810.2021.1888132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: To provide a detailed ophthalmic phenotype of two male patients with Bardet-Biedl Syndrome (BBS) due to mutations in the BBS7 geneMethods: Two brothers ages 26 (Patient 1, P1) and 23 (P2) underwent comprehensive ophthalmic evaluations over three years. Visual function was assessed with full-field electroretinograms (ffERGs), kinetic and chromatic perimetry, multimodal imaging with spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF) with short- (SW) and near-infrared (NIR) excitation lights and adaptive optics scanning light ophthalmoscopy (AOSLO).Results: Both siblings had a history of obesity and postaxial polydactyly; P2 had diagnoses of type 1 Diabetes Mellitus, Addison's disease, high-functioning autism-spectrum disorder and -12D myopia. Visual acuities were better than 20/30. Kinetic fields were moderately constricted. Cone-mediated ffERGs were undetectable, rod ERGs were ~80% of normal mean. Static perimetry showed severe central cone and rod dysfunction. Foveal to parafoveal hypoautofluorescence, most obvious on NIR-FAF, co-localized with outer segment shortening/loss and outer nuclear layer thinning by SD-OCT, and with reduced photoreceptors densities by AOSLO. A structural-functional dissociation was confirmed for cone- and rod-mediated parameters. Worsening of the above abnormalities was documented by SD-OCT and FAF in P2 at 3 years. Gene screening identified compound heterozygous mutations in BBS7 (p.Val266Glu: c.797 T > A of maternal origin; c.1781_1783delCAT, paternal) in both patients.Conclusions: BBS7-associated retinal degeneration may present as a progressive cone-rod dystrophy pattern, reminiscent of both the murine and non-human primate models of the disease. Predominantly central retinal abnormalities in both cone and rod photoreceptors showed a structural-functional dissociation, an ideal scenario for gene augmentation treatments.
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Affiliation(s)
- Tomas S Aleman
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Ophthalmology of the Children's Hospital of Philadelphia, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Erin C O'Neil
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Ophthalmology of the Children's Hospital of Philadelphia, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Keli O'Connor
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu You Jiang
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Isabella A Aleman
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jean Bennett
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jessica I W Morgan
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brian W Toussaint
- Christiana Care Health System, Wilmington, Delaware, USA.,Department of Ophthalmology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
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9
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BBS4 Is Essential for Nuclear Transport of Transcription Factors Mediating Neuronal ER Stress Response. Mol Neurobiol 2020; 58:78-91. [PMID: 32894499 DOI: 10.1007/s12035-020-02104-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 08/27/2020] [Indexed: 11/09/2022]
Abstract
Bardet-Biedl syndrome (BBS) is an autosomal recessive syndrome presenting with retinal dystrophy, cognitive impairment, and obesity. BBS is characterized by elevated endoplasmic reticulum (ER) stress in the early stages of adipocyte and retinal development. BBS expression in the CNS and indications of hippocampal dysgenesis suggest neural development abnormalities. However, the role of BBS in ER stress in neuronal cells has not yet been studied. Therefore, we aimed at studying the role of BBS4 in neuronal development under normal and ER stress conditions. ER stress and unfolded protein response (UPR) were studied in BBS4-silenced (SiBBS4) SH-SY5Y cells during differentiation under normal and stress states, using molecular and biochemical markers. ER stress was demonstrated at early neural differentiation, with significantly augmented expression of UPR markers corresponding to BBS4 expression. In the undifferentiated state, BBS4 silencing resulted in significantly reduced ER-stress markers' expression under normal and ER-stress states. Independent of ER stress, SiBBS4 cells demonstrated significant reduction in activated phospho-IRE1α. Under BBS4 silencing, both sXBP-1 and activated ATF6α p50 failed to translocate to the nucleus. Transcript levels of apoptosis markers were upregulated under BBS4 depletion and ER-stress induction, corresponding to decreased viability. BBS4 depletion in neuronal cells results in reduced sensitivity to ER stress during differentiation and under ER-stress induction, partly due to failure in translocation of ER-transcription factors (TF) sXBP-1 and ATF6α p50 to the nucleus. Hence, BBS4 is essential for nuclear transport under ER-stress response in neuronal cells during early differentiation. Our studies shed light on molecular mechanisms through which BBS4 malfunction alters neuronal ER stress response.
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Chen HY, Kelley RA, Li T, Swaroop A. Primary cilia biogenesis and associated retinal ciliopathies. Semin Cell Dev Biol 2020; 110:70-88. [PMID: 32747192 PMCID: PMC7855621 DOI: 10.1016/j.semcdb.2020.07.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 12/19/2022]
Abstract
The primary cilium is a ubiquitous microtubule-based organelle that senses external environment and modulates diverse signaling pathways in different cell types and tissues. The cilium originates from the mother centriole through a complex set of cellular events requiring hundreds of distinct components. Aberrant ciliogenesis or ciliary transport leads to a broad spectrum of clinical entities with overlapping yet highly variable phenotypes, collectively called ciliopathies, which include sensory defects and syndromic disorders with multi-organ pathologies. For efficient light detection, photoreceptors in the retina elaborate a modified cilium known as the outer segment, which is packed with membranous discs enriched for components of the phototransduction machinery. Retinopathy phenotype involves dysfunction and/or degeneration of the light sensing photoreceptors and is highly penetrant in ciliopathies. This review will discuss primary cilia biogenesis and ciliopathies, with a focus on the retina, and the role of CP110-CEP290-CC2D2A network. We will also explore how recent technologies can advance our understanding of cilia biology and discuss new paradigms for developing potential therapies of retinal ciliopathies.
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Affiliation(s)
- Holly Y Chen
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
| | - Ryan A Kelley
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Tiansen Li
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
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11
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Gorbatyuk MS, Starr CR, Gorbatyuk OS. Endoplasmic reticulum stress: New insights into the pathogenesis and treatment of retinal degenerative diseases. Prog Retin Eye Res 2020; 79:100860. [PMID: 32272207 DOI: 10.1016/j.preteyeres.2020.100860] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 03/08/2020] [Accepted: 03/17/2020] [Indexed: 12/13/2022]
Abstract
Physiological equilibrium in the retina depends on coordinated work between rod and cone photoreceptors and can be compromised by the expression of mutant proteins leading to inherited retinal degeneration (IRD). IRD is a diverse group of retinal dystrophies with multifaceted molecular mechanisms that are not fully understood. In this review, we focus on the contribution of chronically activated unfolded protein response (UPR) to inherited retinal pathogenesis, placing special emphasis on studies employing genetically modified animal models. As constitutively active UPR in degenerating retinas may activate pro-apoptotic programs associated with oxidative stress, pro-inflammatory signaling, dysfunctional autophagy, free cytosolic Ca2+ overload, and altered protein synthesis rate in the retina, we focus on the regulatory mechanisms of translational attenuation and approaches to overcoming translational attenuation in degenerating retinas. We also discuss current research on the role of the UPR mediator PERK and its downstream targets in degenerating retinas and highlight the therapeutic benefits of reprogramming PERK signaling in preclinical animal models of IRD. Finally, we describe pharmacological approaches targeting UPR in ocular diseases and consider their potential applications to IRD.
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Affiliation(s)
- Marina S Gorbatyuk
- The University of Alabama at Birmingham, Department of Optometry and Vision Science, School of Optometry, USA.
| | - Christopher R Starr
- The University of Alabama at Birmingham, Department of Optometry and Vision Science, School of Optometry, USA
| | - Oleg S Gorbatyuk
- The University of Alabama at Birmingham, Department of Optometry and Vision Science, School of Optometry, USA
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12
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Uytingco CR, Green WW, Martens JR. Olfactory Loss and Dysfunction in Ciliopathies: Molecular Mechanisms and Potential Therapies. Curr Med Chem 2019; 26:3103-3119. [PMID: 29303074 DOI: 10.2174/0929867325666180105102447] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 12/08/2017] [Accepted: 12/20/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Ciliopathies are a class of inherited pleiotropic genetic disorders in which alterations in cilia assembly, maintenance, and/or function exhibit penetrance in the multiple organ systems. Olfactory dysfunction is one such clinical manifestation that has been shown in both patients and model organisms. Existing therapies for ciliopathies are limited to the treatment or management of symptoms. The last decade has seen an increase in potential curative therapeutic options including small molecules and biologics. Recent work in multiciliated olfactory sensory neurons has demonstrated the capacity of targeted gene therapy to restore ciliation in terminally differentiated cells and rescue olfactory function. This review will discuss the current understanding of the penetrance of ciliopathies in the olfactory system. Importantly, it will highlight both pharmacological and biological approaches, and their potential therapeutic value in the olfactory system and other ciliated tissues. METHODS We undertook a structured and comprehensive search of peer-reviewed research literature encompassing in vitro, in vivo, model organism, and clinical studies. From these publications, we describe the olfactory system, and discuss the penetrance of ciliopathies and impact of cilia loss on olfactory function. In addition, we outlined the developing therapies for ciliopathies across different organ and cell culture systems, and discussed their potential therapeutic application to the mammalian olfactory system. RESULTS One-hundred sixty-one manuscripts were included in the review, centering on the understanding of olfactory penetrance of ciliopathies, and discussing the potential therapeutic options for ciliopathies in the context of the mammalian olfactory system. Forty-four manuscripts were used to generate a table listing the known congenital causes of olfactory dysfunction, with the first ten listed are linked to ciliopathies. Twenty-three manuscripts were used to outline the potential of small molecules for the olfactory system. Emphasis was placed on HDAC6 inhibitors and lithium, both of which were shown to stabilize microtubule structures, contributing to ciliogenesis and cilia lengthening. Seventy-five manuscripts were used to describe gene therapy and gene therapeutic strategies. Included were the implementation of adenoviral, adeno-associated virus (AAV), and lentiviral vectors to treat ciliopathies across different organ systems and application toward the olfactory system. Thus far, adenoviral and AAVmeditated ciliary restoration demonstrated successful proof-of-principle preclinical studies. In addition, gene editing, ex vivo gene therapy, and transplantation could serve as alternative therapeutic and long-term approaches. But for all approaches, additional assessment of vector immunogenicity, specificity, and efficacy need further investigation. Currently, ciliopathy treatments are limited to symptomatic management with no curative options. However, the accessibility and amenability of the olfactory system to treatment would facilitate development and advancement of a viable therapy. CONCLUSION The findings of this review highlight the contribution of ciliopathies to a growing list of congenial olfactory dysfunctions. Promising results from other organ systems imply the feasibility of biologics, with results from gene therapies proving to be a viable therapeutic option for ciliopathies and olfactory dysfunction.
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Affiliation(s)
- Cedric R Uytingco
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL 32610, United States.,University of Florida Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL 32610, United States
| | - Warren W Green
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL 32610, United States.,University of Florida Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL 32610, United States
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL 32610, United States.,University of Florida Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL 32610, United States
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13
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Brun A, Yu X, Obringer C, Ajoy D, Haser E, Stoetzel C, Roux MJ, Messaddeq N, Dollfus H, Marion V. In vivo phenotypic and molecular characterization of retinal degeneration in mouse models of three ciliopathies. Exp Eye Res 2019; 186:107721. [DOI: 10.1016/j.exer.2019.107721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 05/29/2019] [Accepted: 07/08/2019] [Indexed: 12/17/2022]
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14
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Kretschmer V, Patnaik SR, Kretschmer F, Chawda MM, Hernandez-Hernandez V, May-Simera HL. Progressive Characterization of Visual Phenotype in Bardet-Biedl Syndrome Mutant Mice. Invest Ophthalmol Vis Sci 2019; 60:1132-1143. [PMID: 30901771 DOI: 10.1167/iovs.18-25210] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Bardet-Biedl syndrome (BBS) is an archetypical ciliopathy caused by defective ciliary trafficking and consequent function. Insights gained from BBS mouse models are applicable to other syndromic and nonsyndromic retinal diseases. This progressive characterization of the visual phenotype in three BBS mouse models sets a baseline for testing therapeutic interventions. Methods Longitudinal acquisition of electroretinograms, optical coherence tomography scans, and visual acuity using the optomotor reflex in Bbs6/Mkks, Bbs8/Ttc8, and Bbs5 knockout mice. Gene and protein expression analysis in vivo and in vitro. Results Complete loss of BBS5, BBS6, or BBS8 leads to different rates of retinal degeneration and visual function over time. BBS8-deficient mice showed the fastest rate of degeneration, and BBS8 seems to be required for cone photoreceptors to reach functional maturity. In contrast, the loss of BBS5 (a further BBSome component) showed very little degeneration. Loss of BBS8 versus BBS5 resulted in different physiologic responses both in vivo and in vitro. BBS6-deficient mice show a slower rate of degeneration with both rod and cone function reducing at a similar rate. Conclusions The mouse models analyzed show distinct and diverging courses of degeneration upon loss of BBS5, BBS6, or BBS8, which can be used as a benchmark to test therapeutic interventions. Close consideration of the different phenotypes reveal subtle but important differences relating to their function. Because we also see differences in terms of phenotype depending on the type of visual assessment used, our data highlight the importance of using a combinatorial approach for assessment of visual function.
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Affiliation(s)
- Viola Kretschmer
- Cilia Cell Biology, Institute of Molecular Physiology, Johannes Gutenberg University, Mainz, Germany
| | - Sarita Rani Patnaik
- Cilia Cell Biology, Institute of Molecular Physiology, Johannes Gutenberg University, Mainz, Germany
| | - Friedrich Kretschmer
- Scientific Computing Facility, Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Mira Manilal Chawda
- Genetics and Genomic Medicine Programme, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Victor Hernandez-Hernandez
- Genetics and Genomic Medicine Programme, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom.,Department of Life Sciences, College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Helen Louise May-Simera
- Cilia Cell Biology, Institute of Molecular Physiology, Johannes Gutenberg University, Mainz, Germany
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Balancing the Photoreceptor Proteome: Proteostasis Network Therapeutics for Inherited Retinal Disease. Genes (Basel) 2019; 10:genes10080557. [PMID: 31344897 PMCID: PMC6722924 DOI: 10.3390/genes10080557] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022] Open
Abstract
The light sensing outer segments of photoreceptors (PRs) are renewed every ten days due to their high photoactivity, especially of the cones during daytime vision. This demands a tremendous amount of energy, as well as a high turnover of their main biosynthetic compounds, membranes, and proteins. Therefore, a refined proteostasis network (PN), regulating the protein balance, is crucial for PR viability. In many inherited retinal diseases (IRDs) this balance is disrupted leading to protein accumulation in the inner segment and eventually the death of PRs. Various studies have been focusing on therapeutically targeting the different branches of the PR PN to restore the protein balance and ultimately to treat inherited blindness. This review first describes the different branches of the PN in detail. Subsequently, insights are provided on how therapeutic compounds directed against the different PN branches might slow down or even arrest the appalling, progressive blinding conditions. These insights are supported by findings of PN modulators in other research disciplines.
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16
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The photoreceptor cilium and its diseases. Curr Opin Genet Dev 2019; 56:22-33. [DOI: 10.1016/j.gde.2019.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/21/2019] [Accepted: 05/11/2019] [Indexed: 12/26/2022]
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17
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Wiegering A, Rüther U, Gerhardt C. The Role of Primary Cilia in the Crosstalk between the Ubiquitin⁻Proteasome System and Autophagy. Cells 2019; 8:cells8030241. [PMID: 30875746 PMCID: PMC6468794 DOI: 10.3390/cells8030241] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/06/2019] [Accepted: 03/11/2019] [Indexed: 12/22/2022] Open
Abstract
Protein degradation is a pivotal process for eukaryotic development and homeostasis. The majority of proteins are degraded by the ubiquitin⁻proteasome system and by autophagy. Recent studies describe a crosstalk between these two main eukaryotic degradation systems which allows for establishing a kind of safety mechanism. If one of these degradation systems is hampered, the other compensates for this defect. The mechanism behind this crosstalk is poorly understood. Novel studies suggest that primary cilia, little cellular protrusions, are involved in the regulation of the crosstalk between the two degradation systems. In this review article, we summarise the current knowledge about the association between cilia, the ubiquitin⁻proteasome system and autophagy.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Ulrich Rüther
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
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18
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Vajjala A, Biswas D, Tay WH, Hanski E, Kline KA. Streptolysin-induced endoplasmic reticulum stress promotes group A Streptococcal host-associated biofilm formation and necrotising fasciitis. Cell Microbiol 2018; 21:e12956. [PMID: 30239106 DOI: 10.1111/cmi.12956] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 09/10/2018] [Accepted: 09/12/2018] [Indexed: 12/24/2022]
Abstract
Group A Streptococcus (GAS) is a human pathogen that causes infections ranging from mild to fulminant and life-threatening. Biofilms have been implicated in acute GAS soft-tissue infections such as necrotising fasciitis (NF). However, most in vitro models used to study GAS biofilms have been designed to mimic chronic infections and insufficiently recapitulate in vivo conditions along with the host-pathogen interactions that might influence biofilm formation. Here, we establish and characterise an in vitro model of GAS biofilm development on mammalian cells that simulates microcolony formation observed in a mouse model of human NF. We show that on mammalian cells, GAS forms dense aggregates that display hallmark biofilm characteristics including a 3D architecture and enhanced tolerance to antibiotics. In contrast to abiotic-grown biofilms, host-associated biofilms require the expression of secreted GAS streptolysins O and S (SLO, SLS) that induce endoplasmic reticulum (ER) stress in the host. In an in vivo mouse model, the streptolysin null mutant is attenuated in both microcolony formation and bacterial spread, but pretreatment of soft-tissue with an ER stressor restores the ability of the mutant to form wild-type-like microcolonies that disseminate throughout the soft tissue. Taken together, we have identified a new role of streptolysin-driven ER stress in GAS biofilm formation and NF disease progression.
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Affiliation(s)
- Anuradha Vajjala
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore
| | - Debabrata Biswas
- Cellular and Molecular Mechanisms of Inflammation, Campus for Research Excellence and Technological Enterprise (CREATE), Department of Microbiology and Immunology, National University of Singapore (NUS)-The Hebrew University of Jerusalem (HUJ), Singapore
| | - Wei Hong Tay
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate School, Nanyang Technological University, Singapore
| | - Emanuel Hanski
- Cellular and Molecular Mechanisms of Inflammation, Campus for Research Excellence and Technological Enterprise (CREATE), Department of Microbiology and Immunology, National University of Singapore (NUS)-The Hebrew University of Jerusalem (HUJ), Singapore.,Department of Microbiology and Molecular Genetics, Faculty of Medicine, The Institute for Medical Research, Israel-Canada (IMRIC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore
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Peripheral Gene Therapeutic Rescue of an Olfactory Ciliopathy Restores Sensory Input, Axonal Pathfinding, and Odor-Guided Behavior. J Neurosci 2018; 38:7462-7475. [PMID: 30061191 DOI: 10.1523/jneurosci.0084-18.2018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 07/09/2018] [Accepted: 07/11/2018] [Indexed: 01/08/2023] Open
Abstract
Cilia of olfactory sensory neurons (OSNs) are the primary site of odor binding; hence, their loss results in anosmia, a clinical manifestation of pleiotropic ciliopathies for which there are no curative therapies. We used OSN-specific Ift88 knock-out mice (Ift88osnKO) of both sexes to examine the mechanisms of ciliopathy-induced olfactory dysfunction and the potential for gene replacement to rescue odorant detection, restore olfactory circuitry, and restore odor-guided behaviors. Loss of OSN cilia in Ift88osnKO mice resulted in substantially reduced odor detection and odor-driven synaptic activity in the olfactory bulb (OB). Defects in OSN axon targeting to the OB were also observed in parallel with aberrant odor-guided behavior. Intranasal gene delivery of wild-type IFT88 to Ift88osnKO mice rescued OSN ciliation and peripheral olfactory function. Importantly, this recovery of sensory input in a limited number of mature OSNs was sufficient to restore axonal targeting in the OB of juvenile mice, and with delayed onset in adult mice. In addition, restoration of sensory input re-established course odor-guided behaviors. These findings highlight the spare capacity of the olfactory epithelium and the plasticity of primary synaptic input into the central olfactory system. The restoration of peripheral and central neuronal function supports the potential for treatment of ciliopathy-related anosmia using gene therapy.SIGNIFICANCE STATEMENT Ciliopathies, for which there are no curative therapies, are genetic disorders that alter cilia morphology and/or function in numerous tissue types, including the olfactory system, leading to sensory dysfunction. We show that in vivo intranasal gene delivery restores peripheral olfactory function in a ciliopathy mouse model, including axonal targeting in the juvenile and adult olfactory bulb. Gene therapy also demonstrated restoration of olfactory perception by rescuing odor-guided behaviors. Understanding the therapeutic window and viability for gene therapy to restore odor detection and perception may facilitate translation of therapies to ciliopathy patients with olfactory dysfunctions.
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20
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Starr CR, Pitale PM, Gorbatyuk M. Translational attenuation and retinal degeneration in mice with an active integrated stress response. Cell Death Dis 2018; 9:484. [PMID: 29706649 PMCID: PMC5924758 DOI: 10.1038/s41419-018-0513-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 03/19/2018] [Accepted: 03/22/2018] [Indexed: 12/12/2022]
Abstract
An integrated stress response (ISR), identified in several different animal models of inherited retinal degeneration (IRD), is activated following various cellular stresses. The ISR results in the phosphorylation of eIF2α (p-eIF2α) and a consequent halt in protein synthesis. Although generally protective, persistent elevations in p-eIF2α could lead to cell demise. Therefore, we aimed to determine whether ISR activation is associated with diminished translation rates in mice with IRD. Retinal protein extracts from rd16 mice at different time points were analyzed and the retinal levels of protein synthesis were assessed using the SUnSET method. We found that rd16 mice experience persistent ISR activation: p-eIF2α, ATF4, and CHOP were significantly upregulated at P15 and P20. In agreement with ISR activation, we found that rd16 mice experience translational attenuation at P15. Similar to rd16, other IRD models, T17M RHO, and rd10 also demonstrated a decline in protein synthesis, correlating with p-eIF2α elevation. We then assessed the role of PERK and eIF2α in translational attenuation in rd16 using a PERK inhibitor, GSK2606414. We found that while the treatment significantly reduced p-eIF2α, it did not cause a complete recovery in translation. This suggests that eIF2α is not the only or even the primary point of translational control in IRD, and a second node of translational regulation comprising AKT and mTOR should be evaluated. Surprisingly, we found that AKT-mTOR signaling was diminished in rd16 and rd10 retinas, suggesting a potential link between AKT-mTOR and translational inhibition. Therefore, for the first time, this study shows translation attenuation in IRD models, and highlights the potential roles of eIF2α kinases and AKT-mTOR signaling that could grant valuable insight into the potential treatments for IRD.
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Affiliation(s)
- Christopher R Starr
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Priyamvada M Pitale
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Marina Gorbatyuk
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA.
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21
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McMurtrey JJ, Tso MOM. A review of the immunologic findings observed in retinitis pigmentosa. Surv Ophthalmol 2018; 63:769-781. [PMID: 29551596 DOI: 10.1016/j.survophthal.2018.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 03/12/2018] [Accepted: 03/12/2018] [Indexed: 12/20/2022]
Abstract
Most patients suffering from retinitis pigmentosa (RP) inherit the disorder; however, the immune-pathologic features associated with this disease have yet to be extensively studied. Six reports correlate antiretinal immune activity with vision deterioration in RP patients. Some of these patients have sporadic RP that occurs in excess of expected gene segregation during inheritance. The hypothesis that a primary immune-mediated disease process occurs in this sporadic group is supported by significant associations of RP with autoimmune endocrinopathies and other immune-related conditions or factors; however, no immunologic difference regarding RP family history is reported in the peripheral blood studies of RP patients. Twenty-one percent to 51% of RP patients display antiretinal antibodies, whereas 19-58% have antiretinal lymphocyte reactivity to retinal extract, and 60-85% have activated T cells. Mutations in animal models of RP have been shown to cause endoplasmic reticulum stress that may initiate immunopathology for genetic RP, but oxidative stress also encourages immune cytotoxicity. In addition, necrotic cell death is evident, which promotes inflammatory conditions. We review mechanisms and evidence for an occult inflammation in genetic RP and examine reports of efficacy in retarding RP progression with anti-inflammatory agents in clinical trials.
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Affiliation(s)
- John J McMurtrey
- The Wilmer Ophthalmological Institute, The Johns Hopkins University and Hospital, Baltimore, Maryland, USA.
| | - Mark O M Tso
- The Wilmer Ophthalmological Institute, The Johns Hopkins University and Hospital, Baltimore, Maryland, USA
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22
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Athanasiou D, Aguila M, Bellingham J, Li W, McCulley C, Reeves PJ, Cheetham ME. The molecular and cellular basis of rhodopsin retinitis pigmentosa reveals potential strategies for therapy. Prog Retin Eye Res 2018; 62:1-23. [PMID: 29042326 PMCID: PMC5779616 DOI: 10.1016/j.preteyeres.2017.10.002] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/03/2017] [Accepted: 10/13/2017] [Indexed: 12/12/2022]
Abstract
Inherited mutations in the rod visual pigment, rhodopsin, cause the degenerative blinding condition, retinitis pigmentosa (RP). Over 150 different mutations in rhodopsin have been identified and, collectively, they are the most common cause of autosomal dominant RP (adRP). Mutations in rhodopsin are also associated with dominant congenital stationary night blindness (adCSNB) and, less frequently, recessive RP (arRP). Recessive RP is usually associated with loss of rhodopsin function, whereas the dominant conditions are a consequence of gain of function and/or dominant negative activity. The in-depth characterisation of many rhodopsin mutations has revealed that there are distinct consequences on the protein structure and function associated with different mutations. Here we categorise rhodopsin mutations into seven discrete classes; with defects ranging from misfolding and disruption of proteostasis, through mislocalisation and disrupted intracellular traffic to instability and altered function. Rhodopsin adRP offers a unique paradigm to understand how disturbances in photoreceptor homeostasis can lead to neuronal cell death. Furthermore, a wide range of therapies have been tested in rhodopsin RP, from gene therapy and gene editing to pharmacological interventions. The understanding of the disease mechanisms associated with rhodopsin RP and the development of targeted therapies offer the potential of treatment for this currently untreatable neurodegeneration.
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Affiliation(s)
| | - Monica Aguila
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Wenwen Li
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Caroline McCulley
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Philip J Reeves
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex CO4 3SQ, UK.
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23
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Athanasiou D, Aguila M, Bellingham J, Kanuga N, Adamson P, Cheetham ME. The role of the ER stress-response protein PERK in rhodopsin retinitis pigmentosa. Hum Mol Genet 2017; 26:4896-4905. [PMID: 29036441 PMCID: PMC5868081 DOI: 10.1093/hmg/ddx370] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 08/24/2017] [Accepted: 09/21/2017] [Indexed: 01/05/2023] Open
Abstract
Mutations in rhodopsin, the light-sensitive protein of rod cells, are the most common cause of dominant retinitis pigmentosa (RP), a type of inherited blindness caused by the dysfunction and death of photoreceptor cells. The P23H mutation, the most frequent single cause of RP in the USA, causes rhodopsin misfolding and induction of the unfolded protein response (UPR), an adaptive ER stress response and signalling network that aims to enhance the folding and degradation of misfolded proteins to restore proteostasis. Prolonged UPR activation, and in particular the PERK branch, can reduce protein synthesis and initiate cell death through induction of pro-apoptotic pathways. Here, we investigated the effect of pharmacological PERK inhibition on retinal disease process in the P23H-1 transgenic rat model of retinal degeneration. PERK inhibition with GSK2606414A led to an inhibition of eIF2α phosphorylation, which correlated with reduced ERG function and decreased photoreceptor survival at both high and low doses of PERK inhibitor. Additionally, PERK inhibition increased the incidence of inclusion formation in cultured cells overexpressing P23H rod opsin, and increased rhodopsin aggregation in the P23H-1 rat retina, suggesting enhanced P23H misfolding and aggregation. In contrast, treatment of P23H-1 rats with an inhibitor of eIF2α phosphatase, salubrinal, led to improved photoreceptor survival. Collectively, these data suggest the activation of PERK is part of a protective response to mutant rhodopsin that ultimately limits photoreceptor cell death.
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Affiliation(s)
| | | | | | | | - Peter Adamson
- Ophthiris Discovery Performance Unit, GlaxoSmithKline Ophthalmology, Stevenage SG1 2NY, UK
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Álvarez-Satta M, Castro-Sánchez S, Valverde D. Bardet-Biedl Syndrome as a Chaperonopathy: Dissecting the Major Role of Chaperonin-Like BBS Proteins (BBS6-BBS10-BBS12). Front Mol Biosci 2017; 4:55. [PMID: 28824921 PMCID: PMC5534436 DOI: 10.3389/fmolb.2017.00055] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/13/2017] [Indexed: 01/01/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is a rare genetic disorder that belongs to the group of ciliopathies, defined as diseases caused by defects in cilia structure and/or function. The six diagnostic features considered for this syndrome include retinal dystrophy, obesity, polydactyly, cognitive impairment and renal and urogenital anomalies. Furthermore, three of the 21 genes currently known to be involved in BBS encode chaperonin-like proteins (MKKS/BBS6, BBS10, and BBS12), so BBS can be also considered a member of the growing group of chaperonopathies. Remarkably, up to 50% of clinically-diagnosed BBS families can harbor disease-causing variants in these three genes, which highlights the importance of chaperone defects as pathogenic factors even for genetically heterogeneous syndromes such as BBS. In addition, it is interesting to note that BBS families with deleterious variants in MKKS/BBS6, BBS10 or BBS12 genes generally display more severe phenotypes than families with changes in other BBS genes. The chaperonin-like BBS proteins have structural homology to the CCT family of group II chaperonins, although they are believed to conserve neither the ATP-dependent folding activity of canonical CCT chaperonins nor the ability to form CCT-like oligomeric complexes. Thus, they play an important role in the initial steps of assembly of the BBSome, which is a multiprotein complex essential for mediating the ciliary trafficking activity. In this review, we present a comprehensive review of those genetic, functional and evolutionary aspects concerning chaperonin-like BBS proteins, trying to provide a new perspective that expands the classical conception of BBS only from a ciliary point of view.
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Affiliation(s)
- María Álvarez-Satta
- Grupo de Biomarcadores Moleculares, Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de VigoVigo, Spain.,Grupo de Investigación en Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), SERGAS-UVIGOVigo, Spain.,Centro de Investigaciones Biomédicas (Centro Singular de Investigación de Galicia 2016-2019), Universidad de VigoVigo, Spain
| | - Sheila Castro-Sánchez
- Grupo de Biomarcadores Moleculares, Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de VigoVigo, Spain.,Grupo de Investigación en Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), SERGAS-UVIGOVigo, Spain.,Centro de Investigaciones Biomédicas (Centro Singular de Investigación de Galicia 2016-2019), Universidad de VigoVigo, Spain
| | - Diana Valverde
- Grupo de Biomarcadores Moleculares, Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de VigoVigo, Spain.,Grupo de Investigación en Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), SERGAS-UVIGOVigo, Spain.,Centro de Investigaciones Biomédicas (Centro Singular de Investigación de Galicia 2016-2019), Universidad de VigoVigo, Spain
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25
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Zhu G, Tao L, Wang R, Xue Y, Wang X, Yang S, Sun X, Gao G, Mao Z, Yang Q. Endoplasmic reticulum stress mediates distinct impacts of sevoflurane on different subfields of immature hippocampus. J Neurochem 2017; 142:272-285. [PMID: 28444766 DOI: 10.1111/jnc.14057] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/31/2017] [Accepted: 04/12/2017] [Indexed: 12/12/2022]
Abstract
Sevoflurane, a typical inhaled anesthetic, is widely used in patients of all ages during surgery. The negative effects, such as inducing cell death and damaging spatial memory, of sevoflurane on neurodevelopment have raised increasing concerns in recent years. However, the molecular mechanism remains unclear. This study focused on the crucial role of endoplasmic reticulum (ER) stress in sevoflurane-induced hippocampal injury. Three-week-old rats were exposed to sevoflurane or control air for 5 h with or without ER stress inhibitor (4-phenylbutyric acid, 4-PBA) injection. The hippocampus was harvested to measure the ER stress sensors by western immunoblotting. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling staining was used to detect cell apoptosis and electrophysiology was used to measure the intrinsic excitability of neurons in hippocampus. We measured learning and memory ability by Morris water maze tests 5 weeks after sevoflurane exposure. Interestingly, persistent sevoflurane exposure significantly increased the levels of ER stress sensors in hippocampus. But it resulted in different effects in CA1 and dentate gyrus. Greatly increased caspase-12-mediated apoptotic cells, which were proved to be the neural stem cells, were detected in the dentate gyrus. Meanwhile, CA1 pyramidal neurons exhibited significantly reduced intrinsic excitability. Furthermore, the administration of ER stress inhibitor attenuated the above mentioned detrimental effects evidently and prevented the following relevant learning and memory deficits. In conclusion, sevoflurane-mediated ER stress performs distinct effects on the different subfields of the immature hippocampus and inhibiting ER stress during sevoflurane anesthesia will be a potential method to prevent the following learning and memory deficits in adulthood.
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Affiliation(s)
- Gang Zhu
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Lei Tao
- Department of Anesthesiology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Ronglin Wang
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Ying Xue
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xingqin Wang
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Shaosong Yang
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xude Sun
- Department of Anesthesiology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Guodong Gao
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zixu Mao
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Qian Yang
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
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26
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Abdulkarim B, Hernangomez M, Igoillo-Esteve M, Cunha DA, Marselli L, Marchetti P, Ladriere L, Cnop M. Guanabenz Sensitizes Pancreatic β Cells to Lipotoxic Endoplasmic Reticulum Stress and Apoptosis. Endocrinology 2017; 158:1659-1670. [PMID: 28323924 DOI: 10.1210/en.2016-1773] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/24/2017] [Indexed: 12/18/2022]
Abstract
Deficient as well as excessive/prolonged endoplasmic reticulum (ER) stress signaling can lead to pancreatic β cell failure and the development of diabetes. Saturated free fatty acids (FFAs) such as palmitate induce lipotoxic ER stress in pancreatic β cells. One of the main ER stress response pathways is under the control of the protein kinase R-like endoplasmic reticulum kinase (PERK), leading to phosphorylation of the eukaryotic translation initiation factor 2 (eIF2α). The antihypertensive drug guanabenz has been shown to inhibit eIF2α dephosphorylation and protect cells from ER stress. Here we examined whether guanabenz protects pancreatic β cells from lipotoxicity. Guanabenz induced β cell dysfunction in vitro and in vivo in rodents and led to impaired glucose tolerance. The drug significantly potentiated FFA-induced cell death in clonal rat β cells and in rat and human islets. Guanabenz enhanced FFA-induced eIF2α phosphorylation and expression of the downstream proapoptotic gene C/EBP homologous protein (CHOP), which mediated the sensitization to lipotoxicity. Thus, guanabenz does not protect β cells from ER stress; instead, it potentiates lipotoxic ER stress through PERK/eIF2α/CHOP signaling. These data demonstrate the crucial importance of the tight regulation of eIF2α phosphorylation for the normal function and survival of pancreatic β cells.
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Affiliation(s)
- Baroj Abdulkarim
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Miriam Hernangomez
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | | | - Daniel A Cunha
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Lorella Marselli
- Department of Endocrinology and Metabolism, University of Pisa, 56126 Pisa, Italy
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, University of Pisa, 56126 Pisa, Italy
| | - Laurence Ladriere
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, 1070 Brussels, Belgium
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Abstract
Bardet-Biedl syndrome (BBS) is a rare autosomal recessive genetic disorder. It is characterized by heterogeneous clinical manifestations including primary features of the disease (rod-cone dystrophy, polydactyly, obesity, genital abnormalities, renal defects, and learning difficulties) and secondary BBS characteristics (developmental delay, speech deficit, brachydactyly or syndactyly, dental defects, ataxia or poor coordination, olfactory deficit, diabetes mellitus, congenital heart disease, etc.); most of these symptoms may not be present at birth but appear and progressively worsen during the first and second decades of life. At least 20 BBS genes have already been identified, and all of them are involved in primary cilia functioning. Genetic diagnosis of BBS is complicated due to lack of gene-specific disease symptoms; however, it is gradually becoming more accessible with the invention of multigene sequencing technologies. Clinical management of BBS is largely limited to a symptomatic treatment. Mouse experiments demonstrate that the most debilitating complication of BBS, blindness, can be rescued by topical gene therapy. There is a published case report describing the delay of BBS symptoms by nutritional compensation of the disease-related biochemical deficiencies. Progress in DNA testing technologies is likely to rapidly resolve all limitations in BBS diagnosis; however, much slower improvement is expected with regard to BBS treatment.
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Affiliation(s)
- Evgeny N Suspitsin
- N.N. Petrov Institute of Oncology, St. Petersburg, Russia; St. Petersburg Pediatric Medical University, St. Petersburg, Russia
| | - Evgeny N Imyanitov
- N.N. Petrov Institute of Oncology, St. Petersburg, Russia; St. Petersburg Pediatric Medical University, St. Petersburg, Russia; I.I. Mechnikov North-Western Medical University, St. Petersburg, Russia; St. Petersburg State University, St. Petersburg, Russia
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28
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Salidroside Protects Against 6-Hydroxydopamine-Induced Cytotoxicity by Attenuating ER Stress. Neurosci Bull 2016; 32:61-9. [PMID: 26762342 DOI: 10.1007/s12264-015-0001-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 08/02/2015] [Indexed: 10/22/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disease characterized by a persistent decline of dopaminergic (DA) neurons in the substantia nigra pars compacta. Despite its frequency, effective therapeutic strategies that halt the neurodegenerative processes are lacking, reinforcing the need to better understand the molecular drivers of this disease. Importantly, increasing evidence suggests that the endoplasmic reticulum (ER) stress-induced unfolded protein response is likely involved in DA neuronal death. Salidroside, a major compound isolated from Rhodiola rosea L., possesses potent anti-oxidative stress properties and protects against DA neuronal death. However, the underlying mechanisms are not well understood. In the present study, we demonstrate that salidroside prevents 6-hydroxydopamine (6-OHDA)-induced cytotoxicity by attenuating ER stress. Furthermore, treatment of a DA neuronal cell line (SN4741) and primary cortical neurons with salidroside significantly reduced neurotoxin-induced increases in cytoplasmic reactive oxygen species and calcium, both of which cause ER stress, and cleaved caspase-12, which is responsible for ER stress-induced cell death. Together, these results suggest that salidroside protects SN4741 cells and primary cortical neurons from 6-OHDA-induced neurotoxicity by attenuating ER stress. This provides a rationale for the investigation of salidroside as a potential therapeutic agent in animal models of PD.
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Bhootada Y, Choudhury S, Gully C, Gorbatyuk M. Targeting Caspase-12 to Preserve Vision in Mice With Inherited Retinal Degeneration. Invest Ophthalmol Vis Sci 2015. [PMID: 26207309 DOI: 10.1167/iovs.15-16924] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE The unfolded protein response is known to contribute to the inherited retinal pathology observed in T17M rhodopsin (T17M) mice. Recently it has been demonstrated that the endoplasmic reticulum stress-associated caspase-12 is activated during progression of retinal degeneration in different animal models. Therefore, we wanted to explore the role of caspase-12 in the mechanism of retinopathy in T17M mice and determine if inhibiting apoptosis in this way is a viable approach for halting retinal degeneration. METHODS One, two-, and three-month-old C57BL6/J, caspase-12-/-, T17M, and T17M caspase-12-/- mice were analyzed by scotopic ERG, spectral-domain optical coherence tomography (SD-OCT), histology, quantitative (q)RT-PCR, and Western blot of retinal RNA and protein extracts. Calpain and caspase-3/7 activity assays were measured in postnatal (P) day 30 retinal extracts. RESULTS Caspase-12 ablation significantly prevented a decline in the a- and b-wave ERG amplitudes in T17M mice during three months, increasing the amplitudes from 232% to 212% and from 160% to 138%, respectively, as compared to T17M retinas. The SD-OCT results and photoreceptor row counts demonstrated preservation of retinal structural integrity and postponed photoreceptor cell death. The delay in photoreceptor cell death was due to significant decreases in the activity of caspase-3/7 and calpain, which correlated with an increase in calpastatin expression. CONCLUSIONS We validated caspase-12 as a therapeutic target, ablation of which significantly protects T17M photoreceptors from deterioration. Although the inhibition of apoptotic activity alone was not sufficient to rescue T17M photoreceptors, in combination with other nonapoptotic targets, caspase-12 could be used to treat inherited retinopathy.
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Affiliation(s)
- Yogesh Bhootada
- Department of Vision Sciences University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Shreyasi Choudhury
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, North Texas Eye Research Institute, Fort Worth, Texas, United States
| | - Clark Gully
- Department of Vision Sciences University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Marina Gorbatyuk
- Department of Vision Sciences University of Alabama at Birmingham, Birmingham, Alabama, United States
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Singh R, Kuai D, Guziewicz KE, Meyer J, Wilson M, Lu J, Smith M, Clark E, Verhoeven A, Aguirre GD, Gamm DM. Pharmacological Modulation of Photoreceptor Outer Segment Degradation in a Human iPS Cell Model of Inherited Macular Degeneration. Mol Ther 2015; 23:1700-1711. [PMID: 26300224 DOI: 10.1038/mt.2015.141] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/23/2015] [Indexed: 12/16/2022] Open
Abstract
Degradation of photoreceptor outer segments (POS) by retinal pigment epithelium (RPE) is essential for vision, and studies have implicated altered POS processing in the pathogenesis of some retinal degenerative diseases. Consistent with this concept, a recently established hiPSC-RPE model of inherited macular degeneration, Best disease (BD), displayed reduced rates of POS breakdown. Herein we utilized this model to determine (i) if disturbances in protein degradation pathways are associated with delayed POS digestion and (ii) whether such defect(s) can be pharmacologically targeted. We found that BD hiPSC-RPE cultures possessed increased protein oxidation, decreased free-ubiquitin levels, and altered rates of exosome secretion, consistent with altered POS processing. Application of valproic acid (VPA) with or without rapamycin increased rates of POS degradation in our model, whereas application of bafilomycin-A1 decreased such rates. Importantly, the negative effect of bafilomycin-A1 could be fully reversed by VPA. The utility of hiPSC-RPE for VPA testing was further evident following examination of its efficacy and metabolism in a complementary canine disease model. Our findings suggest that disturbances in protein degradation pathways contribute to the POS processing defect observed in BD hiPSC-RPE, which can be manipulated pharmacologically. These results have therapeutic implications for BD and perhaps other maculopathies.
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Affiliation(s)
- Ruchira Singh
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, USA
| | - David Kuai
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jackelyn Meyer
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Molly Wilson
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jianfeng Lu
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Molly Smith
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eric Clark
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amelia Verhoeven
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Gustavo D Aguirre
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, USA.
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31
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Cognard N, Scerbo MJ, Obringer C, Yu X, Costa F, Haser E, Le D, Stoetzel C, Roux MJ, Moulin B, Dollfus H, Marion V. Comparing the Bbs10 complete knockout phenotype with a specific renal epithelial knockout one highlights the link between renal defects and systemic inactivation in mice. Cilia 2015; 4:10. [PMID: 26273430 PMCID: PMC4535764 DOI: 10.1186/s13630-015-0019-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 07/20/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Bardet-Biedl Syndrome (BBS) is a genetically heterogeneous ciliopathy with clinical cardinal features including retinal degeneration, obesity and renal dysfunction. To date, 20 BBS genes have been identified with BBS10 being a major BBS gene found to be mutated in almost 20 percent of all BBS patients worldwide. It codes for the BBS10 protein which forms part of a chaperone complex localized at the basal body of the primary cilium. Renal dysfunction in BBS patients is one of the major causes of morbidity in human patients and is associated initially with urinary concentration defects related to water reabsorption impairment in renal epithelial cells. The aim of this study was to study and compare the impact of a total Bbs10 inactivation (Bbs10 (-/-)) with that of a specific renal epithelial cells inactivation (Bbs10 (fl/fl) ; Cdh16-Cre (+/-)). RESULTS We generated the Bbs10 (-/-) and Bbs10 (fl/fl) ; Cadh16-Cre (+/-) mouse model and characterized them. Bbs10 (-/-) mice developed obesity, retinal degeneration, structural defects in the glomeruli, polyuria associated with high circulating arginine vasopressin (AVP) concentrations, and vacuolated, yet ciliated, renal epithelial cells. On the other hand, the Bbs10 (fl/fl) ; Cadh16-Cre (+/-)mice displayed no detectable impairment. CONCLUSIONS These data highlight the importance of a systemic Bbs10 inactivation to trigger averted renal dysfunction whereas a targeted absence of BBS10 in the renal epithelium is seemingly non-deleterious.
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Affiliation(s)
- Noëlle Cognard
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France.,Service de Néphrologie-Transplantation, Nouvel Hôpital Civil, 1 place de l'Hôpital, 67091 Strasbourg, France
| | - Maria J Scerbo
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
| | - Cathy Obringer
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
| | - Xiangxiang Yu
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
| | - Fanny Costa
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
| | - Elodie Haser
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
| | - Dane Le
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
| | - Corinne Stoetzel
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
| | - Michel J Roux
- Institut Clinique de la Souris, Illkirch, 67400 Strasbourg, France
| | - Bruno Moulin
- Service de Néphrologie-Transplantation, Nouvel Hôpital Civil, 1 place de l'Hôpital, 67091 Strasbourg, France
| | - Hélène Dollfus
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France.,Service de Génétique Médicale, Institut Génétique Médicale d'Alsace, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Vincent Marion
- Ciliopathies Modeling and Associated Therapies Team, Laboratory of Medical Genetics, National Institute for Health and Medical Research (INSERM), U1112, Université of Strasbourg, 11 rue Humann, 67085 Strasbourg, France
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Álvarez-Satta M, Castro-Sánchez S, Valverde D. Alström syndrome: current perspectives. APPLICATION OF CLINICAL GENETICS 2015; 8:171-9. [PMID: 26229500 PMCID: PMC4516341 DOI: 10.2147/tacg.s56612] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alström syndrome (ALMS) is a rare genetic disorder that has been included in the ciliopathies group, in the last few years. Ciliopathies are a growing group of diseases associated with defects in ciliary structure and function. The development of more powerful genetic approaches has been replaced the strategies to follow for getting a successful molecular diagnosis for these patients, especially for those without the typical ALMS phenotype. In an effort to deepen the understanding of the pathogenesis of ALMS disease, much work has been done, in order to establish the biological implication of ALMS1 protein, which is still being elucidated. In addition to its role in ciliary function and structure maintenance, this protein has been implicated in intracellular trafficking, regulation of cilia signaling pathways, and cellular differentiation, among others. All these progresses will lead to identifying therapeutic targets, thus opening the way to future personalized therapies for human ciliopathies.
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Affiliation(s)
- María Álvarez-Satta
- Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, Vigo, Spain
| | - Sheila Castro-Sánchez
- Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, Vigo, Spain
| | - Diana Valverde
- Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, Vigo, Spain
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33
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Yan Q, Zhu H, Wang FH, Feng JY, Wang WQ, Shi X, Zhou YP, Zhang X, Sun XD. Inhibition of TRB3 Protects Photoreceptors against Endoplasmic Reticulum Stress-Induced Apoptosis after Experimental Retinal Detachment. Curr Eye Res 2015; 41:240-8. [DOI: 10.3109/02713683.2015.1006371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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34
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Wang T, Chen J. Induction of the unfolded protein response by constitutive G-protein signaling in rod photoreceptor cells. J Biol Chem 2014; 289:29310-21. [PMID: 25183010 DOI: 10.1074/jbc.m114.595207] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phototransduction is a G-protein signal transduction cascade that converts photon absorption to a change in current at the plasma membrane. Certain genetic mutations affecting the proteins in the phototransduction cascade cause blinding disorders in humans. Some of these mutations serve as a genetic source of "equivalent light" that activates the cascade, whereas other mutations lead to amplification of the light response. How constitutive phototransduction causes photoreceptor cell death is poorly understood. We showed that persistent G-protein signaling, which occurs in rod arrestin and rhodopsin kinase knock-out mice, caused a rapid and specific induction of the PERK pathway of the unfolded protein response. These changes were not observed in the cGMP-gated channel knock-out rods, an equivalent light condition that mimics light-stimulated channel closure. Thus transducin signaling, but not channel closure, triggers rapid cell death in light damage caused by constitutive phototransduction. Additionally, we show that in the albino light damage model cell death was not associated with increase in global protein ubiquitination or unfolded protein response induction. Taken together, these observations provide novel mechanistic insights into the cell death pathway caused by constitutive phototransduction and identify the unfolded protein response as a potential target for therapeutic intervention.
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Affiliation(s)
- Tian Wang
- From the Program in Genetic, Molecular and Cellular Biology and the Zilkha Neurogenetic Institute, Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Jeannie Chen
- the Zilkha Neurogenetic Institute, Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
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Cao SS, Kaufman RJ. Endoplasmic reticulum stress and oxidative stress in cell fate decision and human disease. Antioxid Redox Signal 2014; 21:396-413. [PMID: 24702237 PMCID: PMC4076992 DOI: 10.1089/ars.2014.5851] [Citation(s) in RCA: 864] [Impact Index Per Article: 86.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
SIGNIFICANCE The endoplasmic reticulum (ER) is a specialized organelle for the folding and trafficking of proteins, which is highly sensitive to changes in intracellular homeostasis and extracellular stimuli. Alterations in the protein-folding environment cause accumulation of misfolded proteins in the ER that profoundly affect a variety of cellular signaling processes, including reduction-oxidation (redox) homeostasis, energy production, inflammation, differentiation, and apoptosis. The unfolded protein response (UPR) is a collection of adaptive signaling pathways that evolved to resolve protein misfolding and restore an efficient protein-folding environment. RECENT ADVANCES Production of reactive oxygen species (ROS) has been linked to ER stress and the UPR. ROS play a critical role in many cellular processes and can be produced in the cytosol and several organelles, including the ER and mitochondria. Studies suggest that altered redox homeostasis in the ER is sufficient to cause ER stress, which could, in turn, induce the production of ROS in the ER and mitochondria. CRITICAL ISSUES Although ER stress and oxidative stress coexist in many pathologic states, whether and how these stresses interact is unknown. It is also unclear how changes in the protein-folding environment in the ER cause oxidative stress. In addition, how ROS production and protein misfolding commit the cell to an apoptotic death and contribute to various degenerative diseases is unknown. FUTURE DIRECTIONS A greater fundamental understanding of the mechanisms that preserve protein folding homeostasis and redox status will provide new information toward the development of novel therapeutics for many human diseases.
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Affiliation(s)
- Stewart Siyan Cao
- 1 Degenerative Diseases Program, Sanford Burnham Medical Research Institute , La Jolla, California
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Guemez-Gamboa A, Coufal NG, Gleeson JG. Primary cilia in the developing and mature brain. Neuron 2014; 82:511-21. [PMID: 24811376 DOI: 10.1016/j.neuron.2014.04.024] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Primary cilia were the largely neglected nonmotile counterparts of their better-known cousin, the motile cilia. For years these nonmotile cilia were considered evolutionary remnants of little consequence to cellular function. Fast forward 10 years and we now recognize primary cilia as key integrators of extracellular ligand-based signaling and cellular polarity, which regulate neuronal cell fate, migration, differentiation, as well as a host of adult behaviors. Important future questions will focus on structure-function relationships, their roles in signaling and disease and as areas of target for treatments.
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Affiliation(s)
- Alicia Guemez-Gamboa
- Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nicole G Coufal
- Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joseph G Gleeson
- Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA.
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Gorbatyuk M, Gorbatyuk O. Review: retinal degeneration: focus on the unfolded protein response. Mol Vis 2013; 19:1985-98. [PMID: 24068865 PMCID: PMC3782367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/18/2013] [Indexed: 11/08/2022] Open
Abstract
Recently published literature has provided evidence that the unfolded protein response (UPR) is involved in the development of retinal degeneration. The scope of these studies encompassed diabetic retinopathy, retinopathy of prematurity, glaucoma, retinal detachment, light-induced retinal degeneration, age-related macular degeneration, and inherited retinal degeneration. Subsequent studies investigating the role of individual UPR markers in retinal pathogenesis and examining the therapeutic potential of reprogramming the UPR as a method for modulating the rate of retinal degeneration have been initiated. Manipulation of UPR markers has been made possible by the use of knockout mice, pharmacological agents, and viral vector-mediated augmentation of gene expression. Future research will aim at identifying specific inhibitors and/or inducers of UPR regulatory markers as well as expand the list of UPR-related animal models. Additionally, adeno-associated virus-mediated gene delivery is a safe and effective method for modulating gene expression, and thus is a useful research tool for manipulating individual UPR markers in affected retinas and a promising delivery vector for gene therapy in retinal degenerative disorders.
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Affiliation(s)
- Marina Gorbatyuk
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35233
| | - Oleg Gorbatyuk
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610
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Nagel-Wolfrum K, Wolfrum U. Vesicle transport and photoreceptor death: fishing for molecular links. Dev Cell 2013; 25:435-6. [PMID: 23763944 DOI: 10.1016/j.devcel.2013.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Intracellular vesicle transport defects can induce retinal degeneration and photoreceptor cell death, but the molecular connections between these processes remains poorly understood. Reporting in Developmental Cell, Nishiwaki et al. (2013) suggest that a vesicle fusion cis-SNARE complex component translates vesicular transport defects into photoreceptor cell apoptosis.
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Affiliation(s)
- Kerstin Nagel-Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, Müllerweg 6, 55099 Mainz, Germany
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Proteasome overload is a common stress factor in multiple forms of inherited retinal degeneration. Proc Natl Acad Sci U S A 2013; 110:9986-91. [PMID: 23716657 DOI: 10.1073/pnas.1305521110] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inherited retinal degenerations, caused by mutations in over 100 individual genes, affect approximately 2 million people worldwide. Many of the underlying mutations cause protein misfolding or mistargeting in affected photoreceptors. This places an increased burden on the protein folding and degradation machinery, which may trigger cell death. We analyzed how these cellular functions are affected in degenerating rods of the transducin γ-subunit (Gγ1) knockout mouse. These rods produce large amounts of transducin β-subunit (Gβ1), which cannot fold without Gγ1 and undergoes intracellular proteolysis instead of forming a transducin βγ-subunit complex. Our data revealed that the most critical pathobiological factor leading to photoreceptor cell death in these animals is insufficient capacity of proteasomes to process abnormally large amounts of misfolded protein. A decrease in the Gβ1 production in Gγ1 knockout rods resulted in a significant reduction in proteasomal overload and caused a striking reversal of photoreceptor degeneration. We further demonstrated that a similar proteasomal overload takes place in photoreceptors of other mutant mice where retinal degeneration has been ascribed to protein mistargeting or misfolding, but not in mice whose photoreceptor degenerate as a result of abnormal phototransduction. These results establish the prominence of proteasomal insufficiency across multiple degenerative diseases of the retina, thereby positioning proteasomes as a promising therapeutic target for treating these debilitating conditions.
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McIntyre JC, Williams CL, Martens JR. Smelling the roses and seeing the light: gene therapy for ciliopathies. Trends Biotechnol 2013; 31:355-63. [PMID: 23601268 DOI: 10.1016/j.tibtech.2013.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/13/2013] [Accepted: 03/14/2013] [Indexed: 10/27/2022]
Abstract
Alterations in cilia formation or function underlie a growing class of pleiotropic disorders termed ciliopathies. The genetic basis of ciliopathies is remarkably complex, with an incomplete but expanding list of more than 89 loci implicated in various disorders. Current treatment of ciliopathies is limited to symptomatic therapy. However, our growing understanding of ciliopathy genetics, coupled with recent advances in gene delivery and endogenous gene and transcript repair demonstrated thus far in tissues of the eye, nose, and airway, offers hope for curative measures in the near future. This review highlights these advances, as well as the challenges that remain with the development of personalized medicine for treating a very complex spectrum of disease, penetrant in a variety of organ systems.
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Affiliation(s)
- Jeremy C McIntyre
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
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Zhu H, Qian J, Wang W, Yan Q, Xu Y, Jiang Y, Zhang L, Lu F, Hu W, Zhang X, Wang F, Sun X. RNA interference of GADD153 protects photoreceptors from endoplasmic reticulum stress-mediated apoptosis after retinal detachment. PLoS One 2013; 8:e59339. [PMID: 23555658 PMCID: PMC3612068 DOI: 10.1371/journal.pone.0059339] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 02/13/2013] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Apoptosis of photoreceptors plays a critical role in the vision loss caused by retinal detachment (RD). Pharmacologic inhibition of photoreceptor cell death may prevent RD. This study investigated the role of GADD153 that participates in endoplasmic reticulum (ER) stress-mediated apoptosis of photoreceptor cells after RD. METHODS Retinal detachment was created in Wistar rats by subretinal injection of hyaluronic acid. The rats were then randomly divided into four groups: normal control group, RD group, GADD153 RNAi group and vehicle group. RNA interference of GADD153 was performed using short hairpin RNA (shRNA). Expressions of GADD153 mRNA and protein were examined by RT-PCR and Western blotting analysis, respectively. GADD153 protein distribution in the retinal cells was observed using immunofluorescence confocal laser scanning microscopy. Apoptosis of retinal cells was determined by TdT-mediated fluorescein-16-dUTP nick-end labeling (TUNEL) assay. RESULTS Lentivirus GADD153 shRNA with the most effective silencing effect was chosen for in vivo animal study and was successfully delivered into the retinal tissues. GADD153 mRNA and protein expressions in GADD153 RNAi group were significantly lower than those in the RD group. Silencing of GADD153 by RNAi protected photoreceptors from ER stress-induced apoptosis. CONCLUSION ER stress-mediated pathway is involved in photoreceptor cell apoptosis after RD. GADD153 is a key regulatory molecule regulating ER-stress pathways and plays a crucial role in the apoptosis of photoreceptor cells after RD.
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Affiliation(s)
- Hong Zhu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Department of Ophthalmology, No.3 People’s Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Jin Qian
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Wenqiu Wang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Quan Yan
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Ying Xu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Yuan Jiang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Lei Zhang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Fengqing Lu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Weiting Hu
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Xi Zhang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
| | - Fenghua Wang
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Fundus Disease, Shanghai, China
- * E-mail: (XS); (FW)
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai First People’s Hospital, School of Medicine, Shanghai JiaoTong University, Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- Eye Research Institute of Shanghai JiaoTong University, Shanghai, China
- * E-mail: (XS); (FW)
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