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Ma JY, Greferath U, Wong JH, Fothergill LJ, Jobling AI, Vessey KA, Fletcher EL. Aging induces cell loss and a decline in phagosome processing in the mouse retinal pigment epithelium. Neurobiol Aging 2023; 128:1-16. [PMID: 37130462 DOI: 10.1016/j.neurobiolaging.2023.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/10/2023] [Accepted: 03/03/2023] [Indexed: 03/14/2023]
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss and dysfunction in the retinal pigment epithelium (RPE) with age is known to contribute to disease development. The aim of this study was to investigate how the C57BL/6J mouse RPE changes with age. RPE structure was found to change with age and eccentricity, with cell size increasing, nuclei lost, and tight junctions altered in the peripheral retina. Phagocytosis of photoreceptor outer segments (POS) by the RPE was investigated using gene expression analysis and histology. RNA-Seq transcriptomic gene profiling of the RPE showed a downregulation of genes involved in phagosome processing and histological analysis showed a decline in phagosome-lysosome association in the aged tissue. In addition, failures in the autophagy pathway that modulates intracellular waste degradation were observed in the aged RPE tissue. These findings highlight that RPE cell loss and slowing of POS processing contribute to RPE dysfunction with age and may predispose the aging eye to AMD development.
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Mondal K, Porter H, Cole J 2nd, Pandya HK, Basu SK, Khanam S, Chiu CY, Shah V, Stephenson DJ, Chalfant CE, Mandal N. Hydroxychloroquine Causes Early Inner Retinal Toxicity and Affects Autophagosome-Lysosomal Pathway and Sphingolipid Metabolism in the Retina. Mol Neurobiol 2022; 59:3873-87. [PMID: 35426574 DOI: 10.1007/s12035-022-02825-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/01/2022] [Indexed: 01/21/2023]
Abstract
Hydroxychloroquine (HCQ) is an anti-malarial drug but also widely used to treat autoimmune diseases like arthritis and lupus. Although there have been multiple reports of the adverse effect of prolonged HCQ usage on the outer retina, leading to bull's-eye maculopathy, the effect of HCQ toxicity on the inner retina as well as on overall visual functions has not been explored in detail. Furthermore, lack of an established animal model of HCQ toxicity hinders our understanding of the underlying molecular mechanisms. Here, using a small clinical study, we confirmed the effect of HCQ toxicity on the inner retina, in particular the reduction in central inner retinal thickness, and established a mouse model of chronic HCQ toxicity that recapitulates the effects observed in human retina. Using the mouse model, we demonstrated that chronic HCQ toxicity results in loss of inner retinal neurons and retinal ganglion cells (RGC) and compromises visual functions. We further established that HCQ treatment prevents autophagosome-lysosome fusion and alters the sphingolipid homeostasis in mouse retina. Our results affirm the notion that HCQ treatment causes early damage to the inner retina and affects visual functions before leading to characteristic toxicity in the macular region of the outer retina, 'bull's-eye maculopathy.' We also provide insights into the underlying molecular mechanisms of HCQ retinal toxicity that may involve autophagy-lysosomal defects and alterations in sphingolipid metabolism.
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Vessey KA, Jobling AI, Tran MX, Wang AY, Greferath U, Fletcher EL. Treatments targeting autophagy ameliorate the age-related macular degeneration phenotype in mice lacking APOE (apolipoprotein E). Autophagy 2022; 18:2368-2384. [PMID: 35196199 PMCID: PMC9542759 DOI: 10.1080/15548627.2022.2034131] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of vision loss with recent evidence indicating an important role for macroautophagy/autophagy in disease progression. In this study we investigate the efficacy of targeting autophagy for slowing dysfunction in a mouse model with features of early AMD. Mice lacking APOE (apolipoprotein E; B6.129P2-Apoetm1UncJ/Arc) and C57BL/6 J- (wild-type, WT) mice were treated with metformin or trehalose in the drinking water from 5 months of age and the ocular phenotype investigated at 13 months. Control mice received normal drinking water. APOE-control mice had reduced retinal function and thickening of Bruch’s membrane consistent with an early AMD phenotype. Immunohistochemical labeling showed reductions in MAP1LC3B/LC3 (microtubule-associated protein 1 light chain 3 beta) and LAMP1 (lysosomal-associated membrane protein 1) labeling in the photoreceptors and retinal pigment epithelium (RPE). This correlated with increased LC3-II:LC3-I ratio and alterations in protein expression in multiple autophagy pathways measured by reverse phase protein array, suggesting autophagy was slowed. Treatment of APOE-mice with metformin or trehalose ameliorated the loss of retinal function and reduced Bruch’s membrane thickening, enhancing LC3 and LAMP1 labeling in the ocular tissues and restoring LC3-II:LC3-I ratio to WT levels. Protein analysis indicated that both treatments boost ATM-AMPK driven autophagy. Additionally, trehalose increased p-MAPK14/p38 to enhance autophagy. Our study shows that treatments targeting pathways to enhance autophagy have the potential for treating early AMD and provide support for the use of metformin, which has been found to reduce the risk of AMD development in human patients.Abbreviations:AMD: age-related macular degeneration; AMPK: 5’ adenosine monophosphate-activated protein kinase APOE: apolipoprotein E; ATM: ataxia telangiectasia mutated; BCL2L1/Bcl-xL: BCL2-like 1; DAPI: 4ʹ-6-diamidino-2-phenylindole; ERG: electroretinogram; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GCL: ganglion cell layer; INL: inner nuclear layer; IPL: inner plexiform layer; IS/OS: inner and outer photoreceptor segments; LAMP1: lysosomal-associated membrane protein 1; MAP1LC3B/LC3: microtubule-associated protein 1 light chain 3 beta; MTOR: mechanistic target of rapamycin kinase; OCT: optical coherence tomography; ONL: outer nuclear layer; OPs: oscillatory potentials; p-EIF4EBP1: phosphorylated eukaryotic translation initiation factor 4E binding protein 1; p-MAPK14/p38: phosphorylated mitogen-activated protein kinase 14; RPE: retinal pigment epithelium; RPS6KB/p70 S6 kinase: ribosomal protein S6 kinase; SQSTM1/p62: sequestosome 1; TP53/TRP53/p53: tumor related protein 53; TSC2: TSC complex subunit 2; WT: wild type
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Affiliation(s)
- Kirstan A Vessey
- Department of Anatomy and Physiology, The University of Melbourne, Level 5, Medical Building, Grattan St, Parkville, Victoria, Australia, 3010
| | - Andrew I Jobling
- Department of Anatomy and Physiology, The University of Melbourne, Level 5, Medical Building, Grattan St, Parkville, Victoria, Australia, 3010
| | - Mai X Tran
- Department of Anatomy and Physiology, The University of Melbourne, Level 5, Medical Building, Grattan St, Parkville, Victoria, Australia, 3010
| | - Anna Y Wang
- Department of Anatomy and Physiology, The University of Melbourne, Level 5, Medical Building, Grattan St, Parkville, Victoria, Australia, 3010
| | - Ursula Greferath
- Department of Anatomy and Physiology, The University of Melbourne, Level 5, Medical Building, Grattan St, Parkville, Victoria, Australia, 3010
| | - Erica L Fletcher
- Department of Anatomy and Physiology, The University of Melbourne, Level 5, Medical Building, Grattan St, Parkville, Victoria, Australia, 3010
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Kim WD, Wilson-Smillie MLDM, Thanabalasingam A, Lefrancois S, Cotman SL, Huber RJ. Autophagy in the Neuronal Ceroid Lipofuscinoses (Batten Disease). Front Cell Dev Biol 2022; 10:812728. [PMID: 35252181 PMCID: PMC8888908 DOI: 10.3389/fcell.2022.812728] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/24/2022] [Indexed: 12/22/2022] Open
Abstract
The neuronal ceroid lipofuscinoses (NCLs), also referred to as Batten disease, are a family of neurodegenerative diseases that affect all age groups and ethnicities around the globe. At least a dozen NCL subtypes have been identified that are each linked to a mutation in a distinct ceroid lipofuscinosis neuronal (CLN) gene. Mutations in CLN genes cause the accumulation of autofluorescent lipoprotein aggregates, called ceroid lipofuscin, in neurons and other cell types outside the central nervous system. The mechanisms regulating the accumulation of this material are not entirely known. The CLN genes encode cytosolic, lysosomal, and integral membrane proteins that are associated with a variety of cellular processes, and accumulated evidence suggests they participate in shared or convergent biological pathways. Research across a variety of non-mammalian and mammalian model systems clearly supports an effect of CLN gene mutations on autophagy, suggesting that autophagy plays an essential role in the development and progression of the NCLs. In this review, we summarize research linking the autophagy pathway to the NCLs to guide future work that further elucidates the contribution of altered autophagy to NCL pathology.
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Affiliation(s)
- William D. Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | | | - Aruban Thanabalasingam
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - Stephane Lefrancois
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique, Laval, QC, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre D'Excellence en Recherche sur Les Maladies Orphelines–Fondation Courtois (CERMO-FC), Université Du Québec à Montréal (UQAM), Montréal, QC, Canada
| | - Susan L. Cotman
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Harvard Medical School, Boston, MA, United States
| | - Robert J. Huber
- Department of Biology, Trent University, Peterborough, ON, Canada
- *Correspondence: Robert J. Huber,
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Liu J, Bassal M, Schlichting S, Braren I, Di Spiezio A, Saftig P, Bartsch U. Intravitreal gene therapy restores the autophagy-lysosomal pathway and attenuates retinal degeneration in cathepsin D-deficient mice. Neurobiol Dis 2022; 164:105628. [PMID: 35033660 DOI: 10.1016/j.nbd.2022.105628] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 11/16/2022] Open
Abstract
Loss of vision due to progressive retinal degeneration is a hallmark of neuronal ceroid lipofuscinoses (NCL), a group of fatal neurodegenerative lysosomal storage diseases. Enzyme substitution therapies represent promising treatment options for NCLs caused by dysfunctions of soluble lysosomal enzymes. Here, we compared the efficacy of a cell-based enzyme substitution strategy and a gene therapy approach to attenuate the retinal pathology in cathepsin D- (CTSD) deficient mice, an animal model of CLN10 disease. Levels of enzymatically active CTSD in mutant retinas were significantly higher after an adeno-associated virus vector-mediated CTSD transfer to retinal glial cells and retinal pigment epithelial cells than after intravitreal transplantations of a CTSD overexpressing clonal neural stem cell line. In line with this finding, the gene therapy treatment restored the disrupted autophagy-lysosomal pathway more effectively than the cell-based approach, as indicated by a complete clearance of storage, significant attenuation of lysosomal hypertrophy, and normalized levels of the autophagy marker sequestosome 1/p62 and microtubule-associated protein 1 light chain 3-II. While the cell-based treatment did not prevent the rapidly progressing loss of various retinal cell types, the gene therapy approach markedly attenuated retinal degeneration as demonstrated by a pronounced rescue of photoreceptor cells and rod bipolar cells.
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Affiliation(s)
- Junling Liu
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Mahmoud Bassal
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Stefanie Schlichting
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Ingke Braren
- Vector Facility, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | | | - Paul Saftig
- Institute of Biochemistry, Christian-Albrechts-University Kiel, 24118 Kiel, Germany
| | - Udo Bartsch
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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Badilla-Porras R, Echeverri-McCandless A, Weimer JM, Ulate-Campos A, Soto-Rodríguez A, Gutiérrez-Mata A, Hernández-Con L, Bogantes-Ledezma S, Balmaceda-Meza A, Brudvig J, Sanabria-Castro A. Neuronal Ceroid Lipofuscinosis Type 6 (CLN6) clinical findings and molecular diagnosis: Costa Rica's experience. Orphanet J Rare Dis 2022; 17:13. [PMID: 35012600 PMCID: PMC8751374 DOI: 10.1186/s13023-021-02162-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 12/19/2021] [Indexed: 02/07/2023] Open
Abstract
Background Commonly known as Batten disease, the neuronal ceroid lipofuscinoses (NCLs) are a genetically heterogeneous group of rare pediatric lysosomal storage disorders characterized by the intracellular accumulation of autofluorescent material (known as lipofuscin), progressive neurodegeneration, and neurological symptoms. In 2002, a disease-causing NCL mutation in the CLN6 gene was identified (c.214G > T) in the Costa Rican population, but the frequency of this mutation among local Batten disease patients remains incompletely characterized, as do clinical and demographic attributes for this rare patient population. Objective To describe the main sociodemographic and clinical characteristics of patients with a clinical diagnosis for Batten Disease treated at the National Children's Hospital in Costa Rica and to characterize via molecular testing their causative mutations. Methods DNA extracted from buccal swabs was used for CLN6 gene sequencing. Participants’ sociodemographic and clinical characteristics were also obtained from their medical records. Results Nine patients with a clinical diagnosis of Batten disease were identified. Genetic sequencing determined the presence of the previously described Costa Rican homozygous mutation in 8 of 9 cases. One patient did not have mutations in the CLN6 gene. In all cases where the Costa Rican CLN6 mutation was present, it was accompanied by a substitution in intron 2. Patients were born in 4 of the 7 Costa Rican provinces, with an average onset of symptoms close to 4 years of age. No parental consanguinity was present in pedigrees. Initial clinical manifestations varied between patients but generally included: gait disturbances, language problems, visual impairment, seizures and psychomotor regression. Cortical and cerebellar atrophy was a constant finding when neuroimaging was performed. Seizure medication was a common element of treatment regimens. Conclusions This investigation supports that the previously characterized c.214G > T mutation is the most common causative NCL mutation in the Costa Rican population. This mutation is geographically widespread among Costa Rican NCL patients and yields a clinical presentation similar to that observed for CLN6 NCL patients in other geographies.
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Affiliation(s)
- R Badilla-Porras
- Clinical Genetic and Metabolism Department, National Children's Hospital, CCSS, San José, Costa Rica
| | | | - J M Weimer
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - A Ulate-Campos
- Neurology Department, National Children's Hospital, CCSS, San José, Costa Rica
| | - A Soto-Rodríguez
- Research Unit, Hospital San Juan de Dios, CCSS, San José, Costa Rica
| | - A Gutiérrez-Mata
- Neurology Department, National Children's Hospital, CCSS, San José, Costa Rica
| | - L Hernández-Con
- Neurology Department, National Children's Hospital, CCSS, San José, Costa Rica
| | - S Bogantes-Ledezma
- Neurology Department, National Children's Hospital, CCSS, San José, Costa Rica
| | | | - J Brudvig
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - A Sanabria-Castro
- Research Unit, Hospital San Juan de Dios, CCSS, San José, Costa Rica.,Pharmacology Department, Pharmacy School, Universidad de Costa Rica, San José, Costa Rica
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Takahashi K, Nakamura S, Shimazawa M, Hara H. Retinal Degeneration and Microglial Dynamics in Mature Progranulin-Deficient Mice. Int J Mol Sci 2021; 22:11557. [PMID: 34768987 DOI: 10.3390/ijms222111557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 11/16/2022] Open
Abstract
Progranulin (PGRN) is a secreted glycoprotein that regulates numerous cellular processes. The role of PGRN as a regulator of lysosomes has recently received attention. The purpose of this study was to characterize the retinal phenotype in mature PGRN knockout (Grn−/−) mice. The a-wave amplitude of scotopic electroretinogram and outer nuclear thickness were significantly reduced at 6 months of age in Grn−/− mice compared to wild-type (Grn+/+) mice. In Grn−/− mice, retinal microglial cells accumulated on the retinal pigment epithelium (RPE) apical layer, and the number of infiltrated microglia and white fundus lesions between 2 and 6 months of age showed a close affinity. In Grn+/+ mice, PGRN was located in the retina, while the strongest PGRN signals were detected in the RPE-choroid. The different effects of PGRN deficiency on the expression of lysosomal proteins between the retina and RPE-choroid were demonstrated. Our data suggest that the subretinal translocation of microglia is a characteristic phenotype in the retina of mature PGRN knockout mice. The different effects of PGRN deficiency on the expression of lysosomal proteins between the retina and RPE-choroid might modulate microglial dynamics in PGRN knockout mice.
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Kick GR, Meiman EJ, Sabol JC, Whiting REH, Ota-Kuroki J, Castaner LJ, Jensen CA, Katz ML. Visual system pathology in a canine model of CLN5 neuronal ceroid lipofuscinosis. Exp Eye Res 2021; 210:108686. [PMID: 34216614 PMCID: PMC8429270 DOI: 10.1016/j.exer.2021.108686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/17/2021] [Accepted: 06/28/2021] [Indexed: 10/21/2022]
Abstract
CLN5 neuronal ceroid lipofuscinosis is a hereditary neurodegenerative disease characterized by progressive neurological decline, vision loss and seizures. Visual impairment in children with CLN5 disease is attributed to a progressive decline in retinal function accompanied by retinal degeneration as well as impaired central nervous system function associated with global brain atrophy. We studied visual system pathology in five Golden Retriever littermates homozygous for the CLN5 disease allele previously identified in the breed. The dogs exhibited signs of pronounced visual impairment by 21-22 months of age. Electroretinogram recordings showed a progressive decline in retinal function primarily affecting cone neural pathways. Altered visual evoked potential recordings indicated that disease progression affected visual signal processing in the brain. Aside from several small retinal detachment lesions, no gross retinal abnormalities were observed with in vivo ocular imaging and histologically the retinas did not exhibit apparent abnormalities by 23 months of age. However, there was extensive accumulation of autofluorescent membrane-bound lysosomal storage bodies in almost all retinal layers, as well as in the occipital cortex, by 20 months of age. In the retina, storage was particularly pronounced in retinal ganglion cells, the retinal pigment epithelium and in photoreceptor cells just interior to the outer limiting membrane. The visual system pathology of CLN5-affected Golden Retrievers is similar to that seen early in the human disease. It was not possible to follow the dogs to an advanced stage of disease progression due to the severity of behavioral and motor disease signs by 23 months of age. The findings reported here indicate that canine CLN5 disease will be a useful model of visual system disease in CLN5 neuronal ceroid lipofuscinosis. The baseline data obtained in this investigation will be useful in future therapeutic intervention studies. The findings indicate that there is a fairly broad time frame after disease onset within which treatments could be effective in preserving vision.
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Affiliation(s)
- Grace Robinson Kick
- Neurodegenerative Diseases Research Laboratory, University of Missouri, Columbia, MO, 65212, USA
| | - Elizabeth J Meiman
- Neurodegenerative Diseases Research Laboratory, University of Missouri, Columbia, MO, 65212, USA
| | - Julianna C Sabol
- Neurodegenerative Diseases Research Laboratory, University of Missouri, Columbia, MO, 65212, USA
| | | | - Juri Ota-Kuroki
- Neurodegenerative Diseases Research Laboratory, University of Missouri, Columbia, MO, 65212, USA
| | - Leilani J Castaner
- Neurodegenerative Diseases Research Laboratory, University of Missouri, Columbia, MO, 65212, USA
| | - Cheryl A Jensen
- Neurodegenerative Diseases Research Laboratory, University of Missouri, Columbia, MO, 65212, USA
| | - Martin L Katz
- Neurodegenerative Diseases Research Laboratory, University of Missouri, Columbia, MO, 65212, USA.
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Bassal M, Liu J, Jankowiak W, Saftig P, Bartsch U. Rapid and Progressive Loss of Multiple Retinal Cell Types in Cathepsin D-Deficient Mice-An Animal Model of CLN10 Disease. Cells 2021; 10:696. [PMID: 33800998 PMCID: PMC8003850 DOI: 10.3390/cells10030696] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/11/2021] [Accepted: 03/19/2021] [Indexed: 12/18/2022] Open
Abstract
Vision loss is among the characteristic symptoms of neuronal ceroid lipofuscinosis (NCL), a fatal neurodegenerative lysosomal storage disorder. Here, we performed an in-depth analysis of retinal degeneration at the molecular and cellular levels in mice lacking the lysosomal aspartyl protease cathepsin D, an animal model of congenital CLN10 disease. We observed an early-onset accumulation of storage material as indicated by elevated levels of saposin D and subunit C of the mitochondrial ATP synthase. The accumulation of storage material was accompanied by reactive astrogliosis and microgliosis, elevated expression of the autophagy marker sequestosome 1/p62 and a dysregulated expression of several lysosomal proteins. The number of cone photoreceptor cells was reduced as early as at postnatal day 5. At the end stage of the disease, the outer nuclear layer was almost atrophied, and all cones were lost. A significant loss of rod and cone bipolar cells, amacrine cells and ganglion cells was found at advanced stages of the disease. Results demonstrate that cathepsin D deficiency results in an early-onset and rapidly progressing retinal dystrophy that involves all retinal cell types. Data of the present study will serve as a reference for studies aimed at developing treatments for retinal degeneration in CLN10 disease.
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Affiliation(s)
- Mahmoud Bassal
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.B.); (J.L.); (W.J.)
| | - Junling Liu
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.B.); (J.L.); (W.J.)
| | - Wanda Jankowiak
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.B.); (J.L.); (W.J.)
| | - Paul Saftig
- Institute of Biochemistry, Christian-Albrechts-University Kiel, 24118 Kiel, Germany;
| | - Udo Bartsch
- Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.B.); (J.L.); (W.J.)
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Weber M, Min SW, Truong T, Hung J, Dale S, Reichelt M, Ubhayakar S, Cain-Hom C, Baca M, Jiang Z, Li Q, Brendza R, Lin H, Kung C, Forrest WF, Quiason-Huynh C, Sandoval W, Chen B, Deng Y, Easton A, Foreman O, Sene A, Bingol B. Ocular phenotypes in a mouse model of impaired glucocerebrosidase activity. Sci Rep 2021; 11:6079. [PMID: 33727605 DOI: 10.1038/s41598-021-85528-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 03/02/2021] [Indexed: 01/08/2023] Open
Abstract
Mutations in the GBA1 gene encoding glucocerebrosidase (GCase) are linked to Gaucher (GD) and Parkinson's Disease (PD). Since some GD and PD patients develop ocular phenotypes, we determined whether ocular phenotypes might result from impaired GCase activity and the corresponding accumulation of glucosylceramide (GluCer) and glucosylsphingosine (GluSph) in the Gba1D409V/D409V knock-in (Gba KI/KI; "KI") mouse. Gba KI mice developed age-dependent pupil dilation deficits to an anti-muscarinic agent; histologically, the iris covered the anterior part of the lens with adhesions between the iris and the anterior surface of the lens (posterior synechia). This may prevent pupil dilation in general, beyond an un-responsiveness of the iris to anti-muscarinics. Gba KI mice displayed atrophy and pigment dispersion of the iris, and occlusion of the iridocorneal angle by pigment-laden cells, reminiscent of secondary open angle glaucoma. Gba KI mice showed progressive thinning of the retina consistent with retinal degeneration. GluSph levels were increased in the anterior and posterior segments of the eye, suggesting that accumulation of lipids in the eye may contribute to degeneration in this compartment. We conclude that the Gba KI model provides robust and reproducible eye phenotypes which may be used to test for efficacy and establish biomarkers for GBA1-related therapies.
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Hargrove-Grimes P, Mondal AK, Gumerson J, Nellissery J, Aponte AM, Gieser L, Qian H, Fariss RN, Bonifacino JS, Li T, Swaroop A. Loss of endocytosis-associated RabGEF1 causes aberrant morphogenesis and altered autophagy in photoreceptors leading to retinal degeneration. PLoS Genet 2020; 16:e1009259. [PMID: 33362196 PMCID: PMC7790415 DOI: 10.1371/journal.pgen.1009259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 01/07/2021] [Accepted: 11/09/2020] [Indexed: 12/17/2022] Open
Abstract
Rab-GTPases and associated effectors mediate cargo transport through the endomembrane system of eukaryotic cells, regulating key processes such as membrane turnover, signal transduction, protein recycling and degradation. Using developmental transcriptome data, we identified Rabgef1 (encoding the protein RabGEF1 or Rabex-5) as the only gene associated with Rab GTPases that exhibited strong concordance with retinal photoreceptor differentiation. Loss of Rabgef1 in mice (Rabgef1-/-) resulted in defects specifically of photoreceptor morphology and almost complete loss of both rod and cone function as early as eye opening; however, aberrant outer segment formation could only partly account for visual function deficits. RabGEF1 protein in retinal photoreceptors interacts with Rabaptin-5, and RabGEF1 absence leads to reduction of early endosomes consistent with studies in other mammalian cells and tissues. Electron microscopy analyses reveal abnormal accumulation of macromolecular aggregates in autophagosome-like vacuoles and enhanced immunostaining for LC3A/B and p62 in Rabgef1-/- photoreceptors, consistent with compromised autophagy. Transcriptome analysis of the developing Rabgef1-/- retina reveals altered expression of 2469 genes related to multiple pathways including phototransduction, mitochondria, oxidative stress and endocytosis, suggesting an early trajectory of photoreceptor cell death. Our results implicate an essential role of the RabGEF1-modulated endocytic and autophagic pathways in photoreceptor differentiation and homeostasis. We propose that RabGEF1 and associated components are potential candidates for syndromic traits that include a retinopathy phenotype. Endocytosis and autophagy are evolutionarily conserved processes that are essential for maintenance of cellular homeostasis. RabGEF1 is a major regulator of the Rab5-GTPase, which participates in key steps during endocytosis and autophagy. We demonstrate that loss of RabGEF1 in mice causes specific developmental defects during photoreceptor outer segment formation, leading to visual dysfunction as early as eye opening followed by retinal degeneration. Rabgef1-/- retina shows a clear reduction in early endosomes as well as accumulation of autophagic vacuoles in developing photoreceptors. Together with transcriptome analysis, our studies suggest a trajectory of cellular events including altered autophagy that precede photoreceptor cell death in the absence of RabGEF1 and establish a critical role of endocytosis and autophagy in retinal development and proteostasis.
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Affiliation(s)
- Passley Hargrove-Grimes
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Institute of Biomedical Sciences, George Washington University, Washington, District of Columbia, United States of America
| | - Anupam K. Mondal
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jessica Gumerson
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jacob Nellissery
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Angel M. Aponte
- Proteomics Core, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Linn Gieser
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Robert N. Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Juan S. Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute for Child Health and Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tiansen Li
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anand Swaroop
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Kakavand K, Jobling AI, Greferath U, Vessey KA, de Iongh RU, Fletcher EL. Photoreceptor Degeneration in Pro23His Transgenic Rats (Line 3) Involves Autophagic and Necroptotic Mechanisms. Front Neurosci 2020; 14:581579. [PMID: 33224023 PMCID: PMC7670078 DOI: 10.3389/fnins.2020.581579] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/02/2020] [Indexed: 01/09/2023] Open
Abstract
Photoreceptor death contributes to 50% of irreversible vision loss in the western world. Pro23His (P23H) transgenic albino rat strains are widely used models for the most common rhodopsin gene mutation associated with the autosomal dominant form of retinitis pigmentosa. However, the mechanism(s) by which photoreceptor death occurs are not well understood and were the principal aim of this study. We first used electroretinogram recording and optical coherence tomography to confirm the time course of functional and structural loss. Electroretinogram analyses revealed significantly decreased rod photoreceptor (a-wave), bipolar cell (b-wave) and amacrine cell responses (oscillatory potentials) from P30 onward. The cone-mediated b-wave was also decreased from P30. TUNEL analysis showed extensive cell death at P18, with continued labeling detected until P30. Focused gene expression arrays indicated activation of, apoptosis, autophagy and necroptosis in whole retina from P14-18. However, analysis of mitochondrial permeability changes (ΔΨm) using JC-1 dye, combined with immunofluorescence markers for caspase-dependent (cleaved caspase-3) and caspase-independent (AIF) cell death pathways, indicated mitochondrial-mediated cell death was not a major contributor to photoreceptor death. By contrast, reverse-phase protein array data combined with RIPK3 and phospho-MLKL immunofluorescence indicated widespread necroptosis as the predominant mechanism of photoreceptor death. These findings highlight the complexity of mechanisms involved in photoreceptor death in the Pro23His rat model of degeneration and suggest therapies that target necroptosis should be considered for their potential to reduce photoreceptor death.
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Affiliation(s)
- Kiana Kakavand
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Andrew I Jobling
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Ursula Greferath
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Kirstan A Vessey
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Robb U de Iongh
- Ocular Development Laboratory, Department Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Erica L Fletcher
- Visual Neuroscience Laboratory, Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
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Butz ES, Chandrachud U, Mole SE, Cotman SL. Moving towards a new era of genomics in the neuronal ceroid lipofuscinoses. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165571. [DOI: 10.1016/j.bbadis.2019.165571] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/12/2019] [Accepted: 10/14/2019] [Indexed: 12/15/2022]
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Atiskova Y, Bartsch S, Danyukova T, Becker E, Hagel C, Storch S, Bartsch U. Mice deficient in the lysosomal enzyme palmitoyl-protein thioesterase 1 (PPT1) display a complex retinal phenotype. Sci Rep 2019; 9:14185. [PMID: 31578378 DOI: 10.1038/s41598-019-50726-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/13/2019] [Indexed: 01/09/2023] Open
Abstract
Neuronal ceroid lipofuscinosis (NCL) type 1 (CLN1) is a neurodegenerative storage disorder caused by mutations in the gene encoding the lysosomal enzyme palmitoyl-protein thioesterase 1 (PPT1). CLN1 patients suffer from brain atrophy, mental and motor retardation, seizures, and retinal degeneration ultimately resulting in blindness. Here, we performed an in-depth analysis of the retinal phenotype of a PPT1-deficient mouse, an animal model of this condition. Reactive astrogliosis and microgliosis were evident in mutant retinas prior to the onset of retinal cell loss. Progressive accumulation of storage material, a pronounced dysregulation of various lysosomal proteins, and accumulation of sequestosome/p62-positive aggregates in the inner nuclear layer also preceded retinal degeneration. At advanced stages of the disease, the mutant retina was characterized by a significant loss of ganglion cells, rod and cone photoreceptor cells, and rod and cone bipolar cells. Results demonstrate that PPT1 dysfunction results in early-onset pathological alterations in the mutant retina, followed by a progressive degeneration of various retinal cell types at relatively late stages of the disease. Data will serve as a reference for future work aimed at developing therapeutic strategies for the treatment of retinal degeneration in CLN1 disease.
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