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Eygeris Y, Henderson MI, Curtis AG, Jozić A, Stoddard J, Reynaga R, Chirco KR, Su GLN, Neuringer M, Lauer AK, Ryals RC, Sahay G. Preformed Vesicle Approach to LNP Manufacturing Enhances Retinal mRNA Delivery. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400815. [PMID: 38738752 DOI: 10.1002/smll.202400815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/20/2024] [Indexed: 05/14/2024]
Abstract
Complete encapsulation of nucleic acids by lipid-based nanoparticles (LNPs) is often thought to be one of the main prerequisites for successful nucleic acid delivery, as the lipid environment protects mRNA from degradation by external nucleases and assists in initiating delivery processes. However, delivery of mRNA via a preformed vesicle approach (PFV-LNPs) defies this precondition. Unlike traditional LNPs, PFV-LNPs are formed via a solvent-free mixing process, leading to a superficial mRNA localization. While demonstrating low encapsulation efficiency in the RiboGreen assay, PFV-LNPs improved delivery of mRNA to the retina by up to 50% compared to the LNP analogs across several benchmark formulations, suggesting the utility of this approach regardless of the lipid composition. Successful mRNA and gene editors' delivery is observed in the retinal pigment epithelium and photoreceptors and validated in mice, non-human primates, and human retinal organoids. Deploying PFV-LNPs in gene editing experiments result in a similar extent of gene editing compared to analogous LNP (up to 3% on genomic level) in the Ai9 reporter mouse model; but, remarkably, retinal tolerability is significantly improved for PFV-LNP treatment. The study findings indicate that the LNP formulation process can greatly influence mRNA transfection and gene editing outcomes, improving LNP treatment safety without sacrificing efficacy.
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Affiliation(s)
- Yulia Eygeris
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR, 97201, USA
| | - Michael I Henderson
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR, 97201, USA
| | - Allison G Curtis
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97201, USA
| | - Antony Jozić
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR, 97201, USA
| | - Jonathan Stoddard
- Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Rene Reynaga
- Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Kathleen R Chirco
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97201, USA
| | - Grace Li-Na Su
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97201, USA
| | - Martha Neuringer
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97201, USA
- Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Andreas K Lauer
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97201, USA
- Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Renee C Ryals
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97201, USA
| | - Gaurav Sahay
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR, 97201, USA
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97201, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, 97201, USA
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2
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Salpeter EM, Moshiri A, Ferneding M, Motta MJ, Park S, Skouritakis C, Thomasy SM. Chromatic Pupillometry as a Putative Screening Tool for Heritable Retinal Disease in Rhesus Macaques. Transl Vis Sci Technol 2023; 12:13. [PMID: 38752621 PMCID: PMC10289275 DOI: 10.1167/tvst.12.6.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 05/22/2023] [Indexed: 05/19/2024] Open
Abstract
Purpose Non-human primates (NHPs) are useful models for human retinal disease. Chromatic pupillometry has been proposed as a noninvasive method of identifying inherited retinal diseases (IRDs) in humans; however, standard protocols employ time-consuming dark adaptation. We utilized shortened and standard dark-adaptation protocols to compare pupillary light reflex characteristics following chromatic stimulation in rhesus macaques with achromatopsia to wild-type (WT) controls with normal retinal function. Methods Nine rhesus macaques homozygous for the p.R656Q mutation (PDE6C HOMs) and nine WT controls were evaluated using chromatic pupillometry following 1-minute versus standard 20-minute dark adaptations. The following outcomes were measured and compared between groups: pupil constriction latency, peak constriction, pupil constriction time, and constriction velocity. Results Pupil constriction latency was significantly longer in PDE6C HOMs with red-light (P = 0.0002) and blue-light (P = 0.04) stimulation versus WT controls. Peak constriction was significantly less in PDE6C HOMs with all light stimulation compared to WT controls (P < 0.0001). Pupil constriction time was significantly shorter in PDE6C HOMs versus WT controls with red-light (P = 0.04) and white-light (P = 0.003) stimulation. Pupil constriction velocity was significantly slower in PDE6C HOMs versus WT controls with red-light (P < 0.0001), blue-light (P < 0.0001), and white-light (P = 0.0002) stimulation. Dark adaptation time only significantly affected peak (P = 0.008) and time of pupil constriction (P = 0.02) following blue-light stimulation. Conclusions Chromatic pupillometry following 1- and 20-minute dark adaptation is an effective tool for screening NHPs for achromatopsia. Translational Relevance Rapid identification of NHPs with IRDs will provide animal research models to advance research and treatment of achromatopia in humans.
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Affiliation(s)
- Elyse M. Salpeter
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Ala Moshiri
- Department of Ophthalmology and Vision Science, School of Medicine, University of California Davis, Davis, CA, USA
| | - Michelle Ferneding
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Monica J. Motta
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Sangwan Park
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Chrisoula Skouritakis
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Sara M. Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
- Department of Ophthalmology and Vision Science, School of Medicine, University of California Davis, Davis, CA, USA
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3
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Kaynezhad P, Tachtsidis I, Sivaprasad S, Jeffery G. Watching the human retina breath in real time and the slowing of mitochondrial respiration with age. Sci Rep 2023; 13:6445. [PMID: 37081065 PMCID: PMC10119193 DOI: 10.1038/s41598-023-32897-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/04/2023] [Indexed: 04/22/2023] Open
Abstract
The retina has the greatest metabolic demand in the body particularly in dark adaptation when its sensitivity is enhanced. This requires elevated level of perfusion to sustain mitochondrial activity. However, mitochondrial performance declines with age leading to reduced adaptive ability. We assessed human retina metabolism in vivo using broad band near-infrared spectroscopy (bNIRS), which records colour changes in mitochondria and blood as retinal metabolism shifts in response to changes in environmental luminance. We demonstrate a significant sustained rise in mitochondrial oxidative metabolism in the first 3 min of darkness in subjects under 50 years old. This was not seen in those over 50 years. Choroidal oxygenation declines in < 50 s as mitochondrial metabolism increases, but gradually rises in the > 50 s. Significant group differences in blood oxygenation are apparent in the first 6 min, consistent with mitochondrial demand leading hemodynamic changes. A greater coupling between mitochondrial oxidative metabolism with hemodynamics is revealed in subjects older than 50, possibly due to reduced capacity in the older retina. Rapid in vivo assessment of retinal metabolism with bNIRS provides a route to understanding fundamental physiology and early identification of retinal disease before pathology is established.
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Affiliation(s)
- Pardis Kaynezhad
- Institute of Ophthalmology, University College London, 11-43 Bath St, London, EC1V9EL, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, Gower St, London, WC1E6BT, UK
| | - Sobha Sivaprasad
- Institute of Ophthalmology, University College London, 11-43 Bath St, London, EC1V9EL, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, 11-43 Bath St, London, EC1V9EL, UK.
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4
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Leong YC, Sowden JC. Modeling Retinitis Pigmentosa with Patient-Derived iPSCs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:555-563. [PMID: 37440086 DOI: 10.1007/978-3-031-27681-1_81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Retinitis pigmentosa (RP) causes blindness in 1 out of 3000-4000 individuals worldwide. Understanding the disease mechanism underlying the death of photoreceptors in RP patient is crucial for the discovery and development of therapies to prevent and stop the progression of retinal degeneration. Despite having provided valuable insight into RP pathology, several shortcomings of animal models warrant the need for a better modeling system. This review discusses the current use of patient-derived induced pluripotent stem cells (iPSCs) to model RP and its advantages over animal models. Further improvement to enhance the representativeness of iPSC RP models is also discussed.
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Affiliation(s)
- Yeh Chwan Leong
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, University College London and NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Jane C Sowden
- Stem Cells and Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, University College London and NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.
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5
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Munds RA, Cooper EB, Janiak MC, Lam LG, DeCasien AR, Bauman Surratt S, Montague MJ, Martinez MI, Research Unit CB, Kawamura S, Higham JP, Melin AD. Variation and heritability of retinal cone ratios in a free-ranging population of rhesus macaques. Evolution 2022; 76:1776-1789. [PMID: 35790204 PMCID: PMC9544366 DOI: 10.1111/evo.14552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/03/2022] [Accepted: 05/12/2022] [Indexed: 01/22/2023]
Abstract
A defining feature of catarrhine primates is uniform trichromacy-the ability to distinguish red (long; L), green (medium; M), and blue (short; S) wavelengths of light. Although the tuning of photoreceptors is conserved, the ratio of L:M cones in the retina is variable within and between species, with human cone ratios differing from other catarrhines. Yet, the sources and structure of variation in cone ratios are poorly understood, precluding a broader understanding of color vision variability. Here, we report a large-scale study of a pedigreed population of rhesus macaques (Macaca mulatta). We collected foveal RNA and analyzed opsin gene expression using cDNA and estimated additive genetic variance of cone ratios. The average L:M ratio and standard error was 1.03:1 ± 0.02. There was no age effect, and genetic contribution to variation was negligible. We found marginal sex effects with females having larger ratios than males. S cone ratios (0.143:1 ± 0.002) had significant genetic variance with a heritability estimate of 43% but did not differ between sexes or age groups. Our results contextualize the derived human condition of L-cone dominance and provide new information about the heritability of cone ratios and variation in primate color vision.
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Affiliation(s)
- Rachel A. Munds
- Department of Anthropology and ArchaeologyUniversity of CalgaryCalgaryABT2N 1N4Canada
| | - Eve B. Cooper
- Department of AnthropologyNew York UniversityNew YorkNew York10003,New York Consortium in Evolutionary PrimatologyNew YorkNew York10460
| | - Mareike C. Janiak
- Department of Anthropology and ArchaeologyUniversity of CalgaryCalgaryABT2N 1N4Canada,Department of AnthropologyNew York UniversityNew YorkNew York10003,School of Science, Engineering and EnvironmentUniversity of SalfordSalfordM5 4NTUnited Kingdom
| | - Linh Gia Lam
- Department of Anthropology and ArchaeologyUniversity of CalgaryCalgaryABT2N 1N4Canada
| | - Alex R. DeCasien
- Department of AnthropologyNew York UniversityNew YorkNew York10003,New York Consortium in Evolutionary PrimatologyNew YorkNew York10460,Section on Developmental NeurogenomicsNational Institute of Mental HealthBethesdaMaryland20892
| | | | - Michael J. Montague
- Department of NeuroscienceUniversity of PennsylvaniaPhiladelphiaPennsylvania19104
| | - Melween I. Martinez
- Caribbean Primate Research CenterUniversity of Puerto RicoSan JuanPuerto Rico00936
| | | | - Shoji Kawamura
- Department of Integrated BiosciencesUniversity of TokyoKashiwa277‐8562Japan
| | - James P. Higham
- Department of AnthropologyNew York UniversityNew YorkNew York10003,New York Consortium in Evolutionary PrimatologyNew YorkNew York10460
| | - Amanda D. Melin
- Department of Anthropology and ArchaeologyUniversity of CalgaryCalgaryABT2N 1N4Canada,Department of Medical GeneticsUniversity of CalgaryCalgaryABT2N 1N4Canada,Alberta Children's Hospital Research InstituteUniversity of CalgaryCalgaryABT2N 1N4Canada
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6
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Bringmann A, Barth T, Wiedemann R, Wiedemann P. Age- and sex-related variations of individual retinal layer thickness in the foveal center of healthy eyes. Exp Eye Res 2022; 219:109038. [DOI: 10.1016/j.exer.2022.109038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/12/2022] [Indexed: 11/26/2022]
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7
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Liu W, Liu S, Li P, Yao K. Retinitis Pigmentosa: Progress in Molecular Pathology and Biotherapeutical Strategies. Int J Mol Sci 2022; 23:ijms23094883. [PMID: 35563274 PMCID: PMC9101511 DOI: 10.3390/ijms23094883] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa (RP) is genetically heterogeneous retinopathy caused by photoreceptor cell death and retinal pigment epithelial atrophy that eventually results in blindness in bilateral eyes. Various photoreceptor cell death types and pathological phenotypic changes that have been disclosed in RP demand in-depth research of its pathogenic mechanism that may account for inter-patient heterogeneous responses to mainstream drug treatment. As the primary method for studying the genetic characteristics of RP, molecular biology has been widely used in disease diagnosis and clinical trials. Current technology iterations, such as gene therapy, stem cell therapy, and optogenetics, are advancing towards precise diagnosis and clinical applications. Specifically, technologies, such as effective delivery vectors, CRISPR/Cas9 technology, and iPSC-based cell transplantation, hasten the pace of personalized precision medicine in RP. The combination of conventional therapy and state-of-the-art medication is promising in revolutionizing RP treatment strategies. This article provides an overview of the latest research on the pathogenesis, diagnosis, and treatment of retinitis pigmentosa, aiming for a convenient reference of what has been achieved so far.
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8
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Zouache MA. Variability in Retinal Neuron Populations and Associated Variations in Mass Transport Systems of the Retina in Health and Aging. Front Aging Neurosci 2022; 14:778404. [PMID: 35283756 PMCID: PMC8914054 DOI: 10.3389/fnagi.2022.778404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/13/2022] [Indexed: 11/17/2022] Open
Abstract
Aging is associated with a broad range of visual impairments that can have dramatic consequences on the quality of life of those impacted. These changes are driven by a complex series of alterations affecting interactions between multiple cellular and extracellular elements. The resilience of many of these interactions may be key to minimal loss of visual function in aging; yet many of them remain poorly understood. In this review, we focus on the relation between retinal neurons and their respective mass transport systems. These metabolite delivery systems include the retinal vasculature, which lies within the inner portion of the retina, and the choroidal vasculature located externally to the retinal tissue. A framework for investigation is proposed and applied to identify the structures and processes determining retinal mass transport at the cellular and tissue levels. Spatial variability in the structure of the retina and changes observed in aging are then harnessed to explore the relation between variations in neuron populations and those seen among retinal metabolite delivery systems. Existing data demonstrate that the relation between inner retinal neurons and their mass transport systems is different in nature from that observed between the outer retina and choroid. The most prominent structural changes observed across the eye and in aging are seen in Bruch’s membrane, which forms a selective barrier to mass transfers at the interface between the choroidal vasculature and the outer retina.
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9
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Little K, Llorián-Salvador M, Scullion S, Hernández C, Simó-Servat O, Del Marco A, Bosma E, Vargas-Soria M, Carranza-Naval MJ, Van Bergen T, Galbiati S, Viganò I, Musi CA, Schlingemann R, Feyen J, Borsello T, Zerbini G, Klaassen I, Garcia-Alloza M, Simó R, Stitt AW. Common pathways in dementia and diabetic retinopathy: understanding the mechanisms of diabetes-related cognitive decline. Trends Endocrinol Metab 2022; 33:50-71. [PMID: 34794851 DOI: 10.1016/j.tem.2021.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/06/2021] [Accepted: 10/29/2021] [Indexed: 12/14/2022]
Abstract
Type 2 diabetes (T2D) is associated with multiple comorbidities, including diabetic retinopathy (DR) and cognitive decline, and T2D patients have a significantly higher risk of developing Alzheimer's disease (AD). Both DR and AD are characterized by a number of pathological mechanisms that coalesce around the neurovascular unit, including neuroinflammation and degeneration, vascular degeneration, and glial activation. Chronic hyperglycemia and insulin resistance also play a significant role, leading to activation of pathological mechanisms such as increased oxidative stress and the accumulation of advanced glycation end-products (AGEs). Understanding these common pathways and the degree to which they occur simultaneously in the brain and retina during diabetes will provide avenues to identify T2D patients at risk of cognitive decline.
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Affiliation(s)
- Karis Little
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - María Llorián-Salvador
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Sarah Scullion
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Cristina Hernández
- Vall d'Hebron Research Institute and CIBERDEM (ISCIII), Barcelona, Spain
| | - Olga Simó-Servat
- Vall d'Hebron Research Institute and CIBERDEM (ISCIII), Barcelona, Spain
| | - Angel Del Marco
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | - Esmeralda Bosma
- Ocular Angiogenesis Group, University of Amsterdam, Amsterdam, The Netherlands
| | - Maria Vargas-Soria
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | - Maria Jose Carranza-Naval
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | | | - Silvia Galbiati
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Ilaria Viganò
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Clara Alice Musi
- Università Degli Studi di Milano and Istituto di Ricerche Farmacologiche Mario Negri- IRCCS, Milano, Italy
| | - Reiner Schlingemann
- Ocular Angiogenesis Group, University of Amsterdam, Amsterdam, The Netherlands; Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Lausanne, Switzerland
| | | | - Tiziana Borsello
- Università Degli Studi di Milano and Istituto di Ricerche Farmacologiche Mario Negri- IRCCS, Milano, Italy
| | - Gianpaolo Zerbini
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Ingeborg Klaassen
- Ocular Angiogenesis Group, University of Amsterdam, Amsterdam, The Netherlands
| | - Monica Garcia-Alloza
- Division of Physiology, School of Medicine, Instituto de Investigacion Biomedica de Cadiz (INIBICA), Universidad de Cadiz, Cadiz, Spain
| | - Rafael Simó
- Vall d'Hebron Research Institute and CIBERDEM (ISCIII), Barcelona, Spain.
| | - Alan W Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK.
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10
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The 3D organisation of mitochondria in primate photoreceptors. Sci Rep 2021; 11:18863. [PMID: 34552195 PMCID: PMC8458444 DOI: 10.1038/s41598-021-98409-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/17/2021] [Indexed: 11/08/2022] Open
Abstract
Vertebrate photoreceptors contain large numbers of closely-packed mitochondria which sustain the high metabolic demands of these cells. These mitochondria populations are dynamic and undergo fusion and fission events. This activity serves to maintain the population in a healthy state. In the event of mitochondrial damage, sub-domains, or indeed whole mitochondria, can be degraded and population homeostasis achieved. If this process is overwhelmed cell death may result. Death of photoreceptors contributes to loss of vision in aging individuals and is associated with many eye diseases. In this study we used serial block face scanning electron microscopy of adult Macaca fascicularis retinae to examine the 3D structure of mitochondria in rod and cone photoreceptors. We show that healthy-looking photoreceptors contain mitochondria exhibiting a range of shapes which are associated with different regions of the cell. In some photoreceptors we observe mitochondrial swelling and other changes often associated with cellular stress. In rods and cones that appear stressed we identify elongated domains of mitochondria with densely-packed normal cristae associated with photoreceptor ciliary rootlet bundles. We observe mitochondrial fission and mitochondrion fragments localised to these domains. Swollen mitochondria with few intact cristae are located towards the periphery of the photoreceptor inner-segment in rods, whilst they are found throughout the cell in cones. Swollen mitochondria exhibit sites on the mitochondrial inner membrane which have undergone complex invagination resulting in membranous, electron-dense aggregates. Membrane contact occurs between the mitochondrion and the photoreceptor plasma membrane in the vicinity of these aggregates, and a series of subsequent membrane fusions results in expulsion of the mitochondrial aggregate from the photoreceptor. These events are primarily associated with rods. The potential fate of this purged material and consequences of its clearance by retinal pigment epithelia are discussed.
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11
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Hu ML, Quinn J, Xue K. Interactions between Apolipoprotein E Metabolism and Retinal Inflammation in Age-Related Macular Degeneration. Life (Basel) 2021; 11:life11070635. [PMID: 34210002 PMCID: PMC8305051 DOI: 10.3390/life11070635] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/24/2021] [Accepted: 06/27/2021] [Indexed: 02/07/2023] Open
Abstract
Age-related macular degeneration (AMD) is a multifactorial retinal disorder that is a major global cause of severe visual impairment. The development of an effective therapy to treat geographic atrophy, the predominant form of AMD, remains elusive due to the incomplete understanding of its pathogenesis. Central to AMD diagnosis and pathology are the hallmark lipid and proteinaceous deposits, drusen and reticular pseudodrusen, that accumulate in the subretinal pigment epithelium and subretinal spaces, respectively. Age-related changes and environmental stressors, such as smoking and a high-fat diet, are believed to interact with the many genetic risk variants that have been identified in several major biochemical pathways, including lipoprotein metabolism and the complement system. The APOE gene, encoding apolipoprotein E (APOE), is a major genetic risk factor for AMD, with the APOE2 allele conferring increased risk and APOE4 conferring reduced risk, in comparison to the wildtype APOE3. Paradoxically, APOE4 is the main genetic risk factor in Alzheimer’s disease, a disease with features of neuroinflammation and amyloid-beta deposition in common with AMD. The potential interactions of APOE with the complement system and amyloid-beta are discussed here to shed light on their roles in AMD pathogenesis, including in drusen biogenesis, immune cell activation and recruitment, and retinal inflammation.
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Affiliation(s)
- Monica L. Hu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia;
| | - Joel Quinn
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK;
| | - Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK;
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
- Correspondence:
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12
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Campello L, Singh N, Advani J, Mondal AK, Corso-Diaz X, Swaroop A. Aging of the Retina: Molecular and Metabolic Turbulences and Potential Interventions. Annu Rev Vis Sci 2021; 7:633-664. [PMID: 34061570 DOI: 10.1146/annurev-vision-100419-114940] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Multifaceted and divergent manifestations across tissues and cell types have curtailed advances in deciphering the cellular events that accompany advanced age and contribute to morbidities and mortalities. Increase in human lifespan during the past century has heightened awareness of the need to prevent age-associated frailty of neuronal and sensory systems to allow a healthy and productive life. In this review, we discuss molecular and physiological attributes of aging of the retina, with a goal of understanding age-related impairment of visual function. We highlight the epigenome-metabolism nexus and proteostasis as key contributors to retinal aging and discuss lifestyle changes as potential modulators of retinal function. Finally, we deliberate promising intervention strategies for promoting healthy aging of the retina for improved vision. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Laura Campello
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Nivedita Singh
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Jayshree Advani
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Anupam K Mondal
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Ximena Corso-Diaz
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
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13
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A Pilot Study Evaluating the Effects of 670 nm Photobiomodulation in Healthy Ageing and Age-Related Macular Degeneration. J Clin Med 2020; 9:jcm9041001. [PMID: 32252424 PMCID: PMC7231137 DOI: 10.3390/jcm9041001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/25/2020] [Accepted: 03/31/2020] [Indexed: 12/28/2022] Open
Abstract
Limited evidence suggests that the application of 670 nm of red light alters the course of aged decline. A previous report on 18 patients showed regression of drusen and improvement in visual functions in patients with intermediate age-related macular degeneration (AMD) by 12 months. We evaluated the functional and structural effects of applying 670 nm light to 31 patients with intermediate AMD and 11 people aged 55 years or above with normal retina. The study eyes were treated daily in the morning with a 670 nm hand-held light source housed in a torch-like tube that emitted energy equivalent to 40 mW/cm2 or 4.8J/ cm2 for 2 min at the viewing aperture. Visual function in terms of best-corrected visual acuity, low luminance visual acuity, scotopic thresholds and rod-intercept time were compared between baseline and 1, 3, 6 and 12 months. Structural changes on optical coherence tomography OCT and colour photographs were also assessed. Five withdrew consent voluntarily due to the intensity of the study visit assessments and two developed neovascular AMD and were excluded from further treatment and the analysis. In normal ageing, there was an improvement in scotopic thresholds in the group with no AMD by 1.77dB (p = 0.03) and no other parameters showed any clinically significant change. In eyes with intermediate AMD, there was no significant improvement in any functional or structural changes at any time point up to 12 months although the compliance was good. This pilot study shows that photobiomodulation with 670 nm has no effect in patients who have already progressed to intermediate AMD.
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