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Van Royen T, Rossey I, Sedeyn K, Schepens B, Saelens X. How RSV Proteins Join Forces to Overcome the Host Innate Immune Response. Viruses 2022; 14:v14020419. [PMID: 35216012 PMCID: PMC8874859 DOI: 10.3390/v14020419] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 12/10/2022] Open
Abstract
Respiratory syncytial virus (RSV) is the leading cause of severe acute lower respiratory tract infections in infants worldwide. Although several pattern recognition receptors (PRRs) can sense RSV-derived pathogen-associated molecular patterns (PAMPs), infection with RSV is typically associated with low to undetectable levels of type I interferons (IFNs). Multiple RSV proteins can hinder the host’s innate immune response. The main players are NS1 and NS2 which suppress type I IFN production and signalling in multiple ways. The recruitment of innate immune cells and the production of several cytokines are reduced by RSV G. Next, RSV N can sequester immunostimulatory proteins to inclusion bodies (IBs). N might also facilitate the assembly of a multiprotein complex that is responsible for the negative regulation of innate immune pathways. Furthermore, RSV M modulates the host’s innate immune response. The nuclear accumulation of RSV M has been linked to an impaired host gene transcription, in particular for nuclear-encoded mitochondrial proteins. In addition, RSV M might also directly target mitochondrial proteins which results in a reduced mitochondrion-mediated innate immune recognition of RSV. Lastly, RSV SH might prolong the viral replication in infected cells and influence cytokine production.
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Affiliation(s)
- Tessa Van Royen
- VIB-UGent Center for Medical Biotechnology, VIB, 9000 Ghent, Belgium; (T.V.R.); (I.R.); (K.S.); (B.S.)
- Department for Biochemistry and Microbiology, Ghent University, 9000 Ghent, Belgium
| | - Iebe Rossey
- VIB-UGent Center for Medical Biotechnology, VIB, 9000 Ghent, Belgium; (T.V.R.); (I.R.); (K.S.); (B.S.)
- Department for Biochemistry and Microbiology, Ghent University, 9000 Ghent, Belgium
| | - Koen Sedeyn
- VIB-UGent Center for Medical Biotechnology, VIB, 9000 Ghent, Belgium; (T.V.R.); (I.R.); (K.S.); (B.S.)
- Department for Biochemistry and Microbiology, Ghent University, 9000 Ghent, Belgium
| | - Bert Schepens
- VIB-UGent Center for Medical Biotechnology, VIB, 9000 Ghent, Belgium; (T.V.R.); (I.R.); (K.S.); (B.S.)
- Department for Biochemistry and Microbiology, Ghent University, 9000 Ghent, Belgium
| | - Xavier Saelens
- VIB-UGent Center for Medical Biotechnology, VIB, 9000 Ghent, Belgium; (T.V.R.); (I.R.); (K.S.); (B.S.)
- Department for Biochemistry and Microbiology, Ghent University, 9000 Ghent, Belgium
- Correspondence:
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Palestine AG, Wagner BD, Patnaik JL, Baldermann R, Mathias MT, Mandava N, Lynch AM. Plasma C-C Chemokine Concentrations in Intermediate Age-Related Macular Degeneration. Front Med (Lausanne) 2021; 8:710595. [PMID: 34869411 PMCID: PMC8636771 DOI: 10.3389/fmed.2021.710595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 10/21/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose: To determine the relationship between plasma concentrations of the C-C chemokines CCL2, CCL3, CCL4, and CCL5 and intermediate age-related macular degeneration (iAMD) patients compared with control inidividuals to further define the inflammatory pathways associated with age-related macular degeneration. Methods: The concentrations of CCL2, CCL3, CCL4, and CCL5 were measured using multiplex assays in plasma collected from 210 patients with iAMD and 102 control individuals with no macular degeneration as defined by multi-modal imaging. Non-inflammatory data included in the analysis were: age, sex, family history of AMD, history of smoking, body mass index, presence of reticular pseudo-drusen and cardiovascular disease. Median concentrations as well as a cutoff value for each chemokine were compared between the two groups. Results: The median concentrations of CCL2 and CCL4 did not differ between control and iAMD groups, however, CCL2 was elevated in iAMD when a cutoff comparison was used (p < 0.05). Median CCL3 and CCL5 concentrations were significantly decreased in the macular degeneration group compared with controls (p < 0.001) as well as when a cutoff value comparison was used. CCL3 and CCL5 were negatively correlated in cases and positively correlated in controls. Conclusions: Plasma CCL3 and CCL5 concentrations were significantly decreased and CCL2 concentrations were increased in patients with iAMD compared with controls, suggesting a role for C-C chemokines in the systemic inflammatory processes associated with disease development.
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Affiliation(s)
- Alan G Palestine
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Brandie D Wagner
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO, United States.,Department of Biostatistics and Informatics, University of Colorado School of Public Health, Aurora, CO, United States
| | - Jennifer L Patnaik
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Rebecca Baldermann
- Colorado Clinical and Translational Sciences Institute, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States
| | - Marc T Mathias
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Naresh Mandava
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Anne M Lynch
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO, United States
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Badia A, Salas A, Duarri A, Ferreira-de-Souza B, Zapata MÁ, Fontrodona L, García-Arumí J. Transcriptomics analysis of Ccl2/Cx3cr1/Crb1 rd8 deficient mice provides new insights into the pathophysiology of progressive retinal degeneration. Exp Eye Res 2020; 203:108424. [PMID: 33373623 DOI: 10.1016/j.exer.2020.108424] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/16/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022]
Abstract
Chronic oxidative stress and immune dysregulation are key mechanisms involved in the pathogenesis of most retinal degenerative diseases, including age-related macular degeneration. The Ccl2-/-/Cx3cr1-/-/Crb1rd8/rd8 mouse model develops a progressive degeneration phenotype, with photoreceptor atrophy, drusen-like lesions or pigment alterations at an early age; however, the role of oxidative stress and immune function in the pathogenesis of the model is poorly understood. We performed a comprehensive characterization of the Ccl2-/-/Cx3cr1-/-/Crb1rd8/rd8 mouse to evaluate how these pathways influence pathogenesis. We generated a Ccl2-/-/Cx3cr1-/- double-knockout (DKO) mouse on a C57BL/6N background (with the rd8 mutation of the Crb1 gene), assessed its retina status and function during 9 months in both in vivo and post-mortem analysis, and performed a comprehensive transcriptomic analysis. DKOrd8 mice presented focal retinal lesions with increased infiltration of microglia and involvement of Müller cells. Lesions progressed to thinning of the photoreceptor nuclear layer, causing a loss in retinal function. Transcriptomics analysis revealed major differential expression of genes involved in oxidative stress and neuronal function, in particular genes related to the mitochondrial electron transport chain and antioxidant cellular response. Our results suggest that alterations in chemokine signaling combined with the rd8 mutation in Ccl2-/-/Cx3cr1-/-/Crb1rd8/rd8 mice involve early changes in several pathways associated with age-related macular degeneration, highlighting the relevance of these processes in the pathological retinal degeneration in the DKOrd8 model.
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Affiliation(s)
- Anna Badia
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - Anna Salas
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - Anna Duarri
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | | | - Miguel Ángel Zapata
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - Laura Fontrodona
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - José García-Arumí
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain; Department of Ophthalmology, Hospital Universitari Vall d'Hebron, Barcelona, Spain.
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Krogh Nielsen M, Subhi Y, Molbech CR, Falk MK, Nissen MH, Sørensen TL. Chemokine Profile and the Alterations in CCR5-CCL5 Axis in Geographic Atrophy Secondary to Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2020; 61:28. [PMID: 32324857 PMCID: PMC7401724 DOI: 10.1167/iovs.61.4.28] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Purpose Geographic atrophy (GA) secondary to age-related macular degeneration (AMD) is a progressive disease with no treatment option. Previous studies show chemokine-mediated recruitment of immune cells in the retina, and therefore we investigated systemic levels of chemokines and chemokine receptors in patients with GA. Methods This observational prospective study was conducted at a single center. We included 122 participants with no immune disease: 41 participants with GA and no choroidal neovascularization, 51 patients with neovascular AMD, and 30 healthy control individuals. Flow cytometric analysis was used to detect expression level of C-C chemokine receptor (CCR)1, CCR2, CCR3, CCR5, and C-X-C motif chemokine receptor (CXCR)3 on peripheral blood mononuclear cells (CD14+ monocytes, CD4+ T cells, CD8+ T cells). Plasma levels of C-C motif ligand (CCL)11, C-X-C motif chemokine (CXCL)10, and CCL5 were measured by specific immunoassays. Enlargement rate of GA lesion was measured from autofluorescence images. Results Participants with GA have a specific chemokine profile with a higher expression of CCR5 than healthy controls in peripheral blood mononuclear cells, and a higher plasma levels of CCL-5. Further, GA was associated with higher monocytic expression of CCR2 than in neovascular AMD. We found that a high expression level of CCR5 on CD8+ T cells was associated with slower enlargement rate of atrophic lesion. Conclusions The study showed an association between systemic chemokine profile and GA formation. Further studies are needed to fully elucidate the possible role of systemic chemokine regulation in mediating pathogenesis of GA.
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Ahsan B, Aldwaikat A, Aboud O, Ramadan A, Abu-Asab MS. Retinal and choroidal capillaries contribution to age-related macular degeneration (AMD) phenotypes in murine models of the disease. Ultrastruct Pathol 2020; 44:174-181. [PMID: 32079449 PMCID: PMC9930639 DOI: 10.1080/01913123.2020.1731039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Mouse models of age-related macular degeneration (AMD) such as Ccl2-/- and Ccl2-/-/Cx3cr1-/- have not yet been fully characterized ultrastructurally. Although we have previously shown extranuclear DNA (enDNA) leakage into the cytoplasm and damaged mitochondria in the retinal pigment epithelium (RPE) of these AMD mouse models, little is known about the state of their vascular capillaries of the retina and choroid. Our ultrastructural survey shows that the aberrations were not restricted to the RPE cells, but also extended to the vasculature of the retina and choroid. Their endothelial aberrations included cytoplasmic degeneration, pyknotic DNA, hypertrophic nuclei, and loss of fenestration in addition to duplication of basement membrane and loss of density in Bruch's membrane. Moreover, the state of the vasculature in the mutant mice models suggests that the capillaries could also be active contributors to the pathological findings seen in AMD. The goal of this study is to gain insights into the early events of AMD that may lead to a better understanding of AMD's pathogenesis, improve our preventative measures, and formulate designed therapeutic regimens that are tailored to target the initial pathological events.Abbreviations: AMD: age-related macular degeneration; BM: Bruch's membrane; DPC: degenerate pericyte; EN: endothelial nucleus; enDNA: extranuclear DNA; GCL: ganglion cell layer; HEN: hypertrophic endothelial nucleus; IPL: inner plexiform layer; NFL: nerve fiber layer; OPL: outer plexiform layer; RBC: red blood cell; RPE: retinal pigment epithelium; SNPs: Single nucleotide polymorphisms.
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Affiliation(s)
- Bisma Ahsan
- Section of Histopathology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ahmad Aldwaikat
- Division of Pulmonary and Critical Care and Sleep Medicine, Wayne State University School of Medicine, Detroit, MI, USA
| | - Orwa Aboud
- Neuro Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ali Ramadan
- Department of Pathology, Howard University Hospital, Washington, DC, USA
| | - Mones S. Abu-Asab
- Section of Histopathology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Abokyi S, To CH, Lam TT, Tse DY. Central Role of Oxidative Stress in Age-Related Macular Degeneration: Evidence from a Review of the Molecular Mechanisms and Animal Models. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7901270. [PMID: 32104539 PMCID: PMC7035553 DOI: 10.1155/2020/7901270] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 01/18/2020] [Indexed: 11/17/2022]
Abstract
Age-related macular degeneration (AMD) is a common cause of visual impairment in the elderly. There are very limited therapeutic options for AMD with the predominant therapies targeting vascular endothelial growth factor (VEGF) in the retina of patients afflicted with wet AMD. Hence, it is important to remind readers, especially those interested in AMD, about current studies that may help to develop novel therapies for other stages of AMD. This study, therefore, provides a comprehensive review of studies on human specimens as well as rodent models of the disease, to identify and analyze the molecular mechanisms behind AMD development and progression. The evaluation of this information highlights the central role that oxidative damage in the retina plays in contributing to major pathways, including inflammation and angiogenesis, found in the AMD phenotype. Following on the debate of oxidative stress as the earliest injury in the AMD pathogenesis, we demonstrated how the targeting of oxidative stress-associated pathways, such as autophagy and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling, might be the futuristic direction to explore in the search of an effective treatment for AMD, as the dysregulation of these mechanisms is crucial to oxidative injury in the retina. In addition, animal models of AMD have been discussed in great detail, with their strengths and pitfalls included, to assist inform in the selection of suitable models for investigating any of the molecular mechanisms.
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Affiliation(s)
- Samuel Abokyi
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
- Department of Optometry, University of Cape Coast, Ghana
| | - Chi-Ho To
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
| | - Tim T. Lam
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
| | - Dennis Y. Tse
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
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Phenotypic Differences in Primary Murine Microglia Treated with NOD1, NOD2, and NOD1/2 Agonists. J Mol Neurosci 2020; 70:600-609. [PMID: 31907866 DOI: 10.1007/s12031-019-01466-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 12/09/2019] [Indexed: 12/20/2022]
Abstract
The purpose of the study was studying the influence of different NOD agonists on the morphological phenotype of primary murine microglia and to examine their influence on characteristic cytokines. Primary CD11b-positive cells were isolated from the brain of neonatal mice. The microglial phenotype of the cells was examined by ionized calcium-binding adapter molecule (Iba)1 staining. After14 days in culture, these cells were stimulated by iE-DAP, L18-MDP, or M-TriDAP as NOD1, NOD2, and NOD1/2 agonists, respectively. The cellular morphology was recorded and compared to the phenotype of cells cultured in medium alone or after LPS stimulation. The cells developed a specific phenotype only after treatment with the NOD2 agonist L18-MDP. These cells were characterized by straight extensions carrying tiny spikes and had a high ramification index. This was in sharp contrast to all other treatments, which always resulted in an amoeboid phenotype typically shown by activated microglia in vivo and by cultured microglia in vitro. The staining intensity of IL-6 and TNF-α did not reveal any clear difference independent of the NOD agonist treatment. In contrast, an increased staining intensity was observed for IL-10 after L18-MDP treatment. The NOD2 agonist L18-MDP induced a morphologically distinct phenotype characterized by microspike-decorated dendritiform extensions and a high degree of ramification in primary murine microglia. Increased ramification index and elevated staining intensity of anti-inflammatory IL-10 as hallmarks suggest that a M2-like phenotype of microglia was induced.
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Harris CL, Pouw RB, Kavanagh D, Sun R, Ricklin D. Developments in anti-complement therapy; from disease to clinical trial. Mol Immunol 2018; 102:89-119. [PMID: 30121124 DOI: 10.1016/j.molimm.2018.06.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 02/06/2023]
Abstract
The complement system is well known for its role in innate immunity and in maintenance of tissue homeostasis, providing a first line of defence against infection and playing a key role in flagging apoptotic cells and debris for disposal. Unfortunately complement also contributes to pathogenesis of a number of diseases; in some cases driving pathology, and in others amplifying or exacerbating the inflammatory and damaging impact of non-complement disease triggers. The role of complement in pathogenesis of an expanding number of diseases has driven industry and academia alike to develop an impressive arsenal of anti-complement drugs which target different proteins and functions of the complement cascade. Evidence from genetic and biochemical analyses, combined with improved identification of complement biomarkers and supportive data from sophisticated animal models of disease, has driven a drug development landscape in which the indications selected for clinical trial cluster in three 'target' tissues: the kidney, eye and vasculature. While the disease triggers may differ, complement activation and amplification is a common feature in many diseases which affect these three tissues. An abundance of drugs are in clinical development, some show favourable progression whereas others experience significant challenges. However, these hurdles in themselves drive an ever-evolving portfolio of 'next-generation' drugs with improved pharmacokinetic and pharmacodynamics properties. In this review we discuss the indications which are in the drug development 'spotlight' and review the relevant indication validation criteria. We present current progress in clinical trials, highlighting successes and difficulties, and look forward to approval of a wide selection of drugs for use in man which give clinicians choice in mechanistic target, modality and route of delivery.
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Affiliation(s)
- Claire L Harris
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK.
| | - Richard B Pouw
- Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056, Basel, Switzerland
| | - David Kavanagh
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK
| | - Ruyue Sun
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Daniel Ricklin
- Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056, Basel, Switzerland.
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Kersten E, Paun CC, Schellevis RL, Hoyng CB, Delcourt C, Lengyel I, Peto T, Ueffing M, Klaver CCW, Dammeier S, den Hollander AI, de Jong EK. Systemic and ocular fluid compounds as potential biomarkers in age-related macular degeneration. Surv Ophthalmol 2017; 63:9-39. [PMID: 28522341 DOI: 10.1016/j.survophthal.2017.05.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 12/15/2022]
Abstract
Biomarkers can help unravel mechanisms of disease and identify new targets for therapy. They can also be useful in clinical practice for monitoring disease progression, evaluation of treatment efficacy, and risk assessment in multifactorial diseases, such as age-related macular degeneration (AMD). AMD is a highly prevalent progressive retinal disorder for which multiple genetic and environmental risk factors have been described, but the exact etiology is not yet fully understood. Many compounds have been evaluated for their association with AMD. We performed an extensive literature review of all compounds measured in serum, plasma, vitreous, aqueous humor, and urine of AMD patients. Over 3600 articles were screened, resulting in more than 100 different compounds analyzed in AMD studies, involved in neovascularization, immunity, lipid metabolism, extracellular matrix, oxidative stress, diet, hormones, and comorbidities (such as kidney disease). For each compound, we provide a short description of its function and discuss the results of the studies in relation to its usefulness as AMD biomarker. In addition, biomarkers identified by hypothesis-free techniques, including metabolomics, proteomics, and epigenomics, are covered. In summary, compounds belonging to the oxidative stress pathway, the complement system, and lipid metabolism are the most promising biomarker candidates for AMD. We hope that this comprehensive survey of the literature on systemic and ocular fluid compounds as potential biomarkers in AMD will provide a stepping stone for future research and possible implementation in clinical practice.
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Affiliation(s)
- Eveline Kersten
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Constantin C Paun
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Rosa L Schellevis
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Cécile Delcourt
- Université de Bordeaux, ISPED, Bordeaux, France; INSERM, U1219-Bordeaux Population Health Research Center, Bordeaux, France
| | - Imre Lengyel
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Northern Ireland, United Kingdom
| | - Tunde Peto
- Centre for Public Health, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Northern Ireland, United Kingdom
| | - Marius Ueffing
- Department for Ophthalmology and Medical Bioanalytics Centre Tübingen, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Caroline C W Klaver
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Sascha Dammeier
- Department for Ophthalmology and Medical Bioanalytics Centre Tübingen, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Eiko K de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.
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Lyzogubov VV, Bora PS, Wu X, Horn LE, de Roque R, Rudolf XV, Atkinson JP, Bora NS. The Complement Regulatory Protein CD46 Deficient Mouse Spontaneously Develops Dry-Type Age-Related Macular Degeneration-Like Phenotype. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2088-2104. [PMID: 27295359 PMCID: PMC4973660 DOI: 10.1016/j.ajpath.2016.03.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 03/28/2016] [Accepted: 03/31/2016] [Indexed: 11/20/2022]
Abstract
In the mouse, membrane cofactor protein (CD46), a key regulator of the alternative pathway of the complement system, is only expressed in the eye and on the inner acrosomal membrane of spermatozoa. We noted that although Cd46(-/-) mice have normal systemic alternative pathway activating ability, lack of CD46 leads to dysregulated complement activation in the eye, as evidenced by increased deposition of C5b-9 in the retinal pigment epithelium (RPE) and choroid. A knockout of CD46 induced the following cardinal features of human dry age-related macular degeneration (AMD) in 12-month-old male and female mice: accumulation of autofluorescent material in and hypertrophy of the RPE, dense deposits in and thickening of Bruch's membrane, loss of photoreceptors, cells in subretinal space, and a reduction of choroidal vessels. Collectively, our results demonstrate spontaneous age-related degenerative changes in the retina, RPE, and choroid of Cd46(-/-) mice that are consistent with human dry AMD. These findings provide the exciting possibility of using Cd46(-/-) mice as a convenient and reliable animal model for dry AMD. Having such a relatively straight-forward model for dry AMD should provide valuable insights into pathogenesis and a test model system for novel drug targets. More important, tissue-specific expression of CD46 gives the Cd46(-/-) mouse model of dry AMD a unique advantage over other mouse models using knockout strains.
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Affiliation(s)
- Valeriy V Lyzogubov
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Puran S Bora
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Xiaobo Wu
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Leah E Horn
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas; Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Ryan de Roque
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas; University of Arkansas for Medical Sciences, College of Medicine, Little Rock, Arkansas
| | - Xeniya V Rudolf
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - John P Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Nalini S Bora
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas; Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
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11
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Kauppinen A, Paterno JJ, Blasiak J, Salminen A, Kaarniranta K. Inflammation and its role in age-related macular degeneration. Cell Mol Life Sci 2016; 73:1765-86. [PMID: 26852158 PMCID: PMC4819943 DOI: 10.1007/s00018-016-2147-8] [Citation(s) in RCA: 445] [Impact Index Per Article: 55.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/21/2016] [Accepted: 01/25/2016] [Indexed: 01/05/2023]
Abstract
Inflammation is a cellular response to factors that challenge the homeostasis of cells and tissues. Cell-associated and soluble pattern-recognition receptors, e.g. Toll-like receptors, inflammasome receptors, and complement components initiate complex cellular cascades by recognizing or sensing different pathogen and damage-associated molecular patterns, respectively. Cytokines and chemokines represent alarm messages for leukocytes and once activated, these cells travel long distances to targeted inflamed tissues. Although it is a crucial survival mechanism, prolonged inflammation is detrimental and participates in numerous chronic age-related diseases. This article will review the onset of inflammation and link its functions to the pathogenesis of age-related macular degeneration (AMD), which is the leading cause of severe vision loss in aged individuals in the developed countries. In this progressive disease, degeneration of the retinal pigment epithelium (RPE) results in the death of photoreceptors, leading to a loss of central vision. The RPE is prone to oxidative stress, a factor that together with deteriorating functionality, e.g. decreased intracellular recycling and degradation due to attenuated heterophagy/autophagy, induces inflammation. In the early phases, accumulation of intracellular lipofuscin in the RPE and extracellular drusen between RPE cells and Bruch's membrane can be clinically detected. Subsequently, in dry (atrophic) AMD there is geographic atrophy with discrete areas of RPE loss whereas in the wet (exudative) form there is neovascularization penetrating from the choroid to retinal layers. Elevations in levels of local and systemic biomarkers indicate that chronic inflammation is involved in the pathogenesis of both disease forms.
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Affiliation(s)
- Anu Kauppinen
- Faculty of Health Sciences, School of Pharmacy, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland.
| | - Jussi J Paterno
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
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12
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Tuo J, Wang Y, Cheng R, Li Y, Chen M, Qiu F, Qian H, Shen D, Penalva R, Xu H, Ma JX, Chan CC. Wnt signaling in age-related macular degeneration: human macular tissue and mouse model. J Transl Med 2015; 13:330. [PMID: 26476672 PMCID: PMC4609061 DOI: 10.1186/s12967-015-0683-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 09/29/2015] [Indexed: 01/02/2023] Open
Abstract
Background The wingless-type MMTV integration site (Wnt) signaling is a group of signal transduction pathways. In canonical Wnt pathway, Wnt ligands bind to low-density lipoprotein receptor-related protein 5 or 6 (LRP5 or LRP6), resulting in phosphorylation and activation of the receptor. We hypothesize that canonical Wnt pathway plays a role in the retinal lesion of age-related macular degeneration (AMD), a leading cause of irreversible central visual loss in elderly. Methods We examined LRP6 phosphorylation and Wnt signaling cascade in human retinal sections and plasma kallistatin, an endogenous inhibitor of the Wnt pathway in AMD patients and non-AMD subjects. We also used the Ccl2−/−/Cx3cr1−/−/rd8 and Ccl2−/−/Cx3cr1gfp/gfp mouse models with AMD-like retinal degeneration to further explore the involvement of Wnt signaling activation in the retinal lesions in those models and to preclinically evaluate the role of Wnt signaling suppression as a potential therapeutic option for AMD. Results We found higher levels of LRP6 (a key Wnt signaling receptor) protein phosphorylation and transcripts of the Wnt pathway-targeted genes, as well as higher beta-catenin protein in AMD macula compared to controls. Kallistatin was decreased in the plasma of AMD patients. Retinal non-phosphorylated-β-catenin and phosphorylated-LRP6 were higher in Ccl2−/−/Cx3cr1−/−/rd8 mice than that in wild type. Intravitreal administration of an anti-LRP6 antibody slowed the progression of retinal lesions in Ccl2−/−/Cx3cr1−/−/rd8 and Ccl2−/−/Cx3cr1gfp/gfp mice. Electroretinography of treated eyes exhibited larger amplitudes compared to controls in both mouse models. A2E, a retinoid byproduct associated with AMD was lower in the treated eyes of Ccl2−/−/Cx3cr1−/−/rd8 mice. Anti-LRP6 also suppressed the expression of Tnf-α and Icam-1 in Ccl2−/−/Cx3cr1−/−/rd8 retinas. Conclusions Wnt signaling may be disturbed in AMD patients, which could contribute to the retinal inflammation and increased A2E levels found in AMD. Aberrant activation of canonical Wnt signaling might also contribute to the focal retinal degenerative lesions of mouse models with Ccl2 and Cx3cr1 deficiency, and intravitreal administration of anti-LRP6 antibody could be beneficial by deactivating the canonical Wnt pathway. Electronic supplementary material The online version of this article (doi:10.1186/s12967-015-0683-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jingsheng Tuo
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, 10 Center Drive, Bldg. 10, Rm. 10N103, NIH/NEI, Bethesda, MD, 20892-1857, USA.
| | - Yujuan Wang
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, 10 Center Drive, Bldg. 10, Rm. 10N103, NIH/NEI, Bethesda, MD, 20892-1857, USA.
| | - Rui Cheng
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Yichao Li
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Mei Chen
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK.
| | - Fangfang Qiu
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Defen Shen
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, 10 Center Drive, Bldg. 10, Rm. 10N103, NIH/NEI, Bethesda, MD, 20892-1857, USA.
| | - Rosana Penalva
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK.
| | - Heping Xu
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK.
| | - Jian-Xing Ma
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Chi-Chao Chan
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, 10 Center Drive, Bldg. 10, Rm. 10N103, NIH/NEI, Bethesda, MD, 20892-1857, USA.
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Stewart EA, Wei R, Branch MJ, Sidney LE, Amoaku WM. Expression of Toll-like receptors in human retinal and choroidal vascular endothelial cells. Exp Eye Res 2015; 138:114-23. [DOI: 10.1016/j.exer.2015.06.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 05/13/2015] [Accepted: 06/15/2015] [Indexed: 01/18/2023]
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Li L, Eter N, Heiduschka P. The microglia in healthy and diseased retina. Exp Eye Res 2015; 136:116-30. [PMID: 25952657 DOI: 10.1016/j.exer.2015.04.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 12/25/2022]
Abstract
The microglia are the immune cells of the central nervous system and, also the retina. They fulfil several tasks of surveillance in the healthy retina. In case of an injury or disease, microglia become activated and tries to repair the damage. However, in a lot of cases it does not work, and microglia deteriorate the situation by releasing toxic and pro-inflammatory compounds. Moreover, they further promote degenerative processes by attacking and phagocytosing damaged neurones and photoreceptors that otherwise would possibly have the chance to survive. Such deleterious action of the microglia has been observed in degeneration of retinal ganglion cells and photoreceptors, and it takes place in hereditary diseases, infections as well as in case of traumatic or light injuries. Therefore, a number of attempts has been undertaken so far to inhibit the microglia, with varying success. The task remains to study behaviour of the microglia and their interaction with other retinal cell populations in more detail with respect to released factors and expressed receptors including the time points of the corresponding events. The goal has to be to find a better balance between helpful and detrimental actions of the microglia.
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Affiliation(s)
- Lu Li
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany
| | - Nicole Eter
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany
| | - Peter Heiduschka
- University of Münster Medical School, Department of Ophthalmology, Domagkstr. 15, D-48149 Münster, Germany.
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16
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Lyzogubov VV, Bora NS, Tytarenko RG, Bora PS. Polyethylene glycol induced mouse model of retinal degeneration. Exp Eye Res 2014; 127:143-52. [PMID: 25088354 DOI: 10.1016/j.exer.2014.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/15/2014] [Accepted: 07/23/2014] [Indexed: 12/31/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible blindness. This study was done to characterize dry AMD-like changes in mouse retinal pigment epithelium (RPE) and retina after polyethylene glycol (PEG) treatment. We injected male C57BL/6 mice subretinally with PBS, 0.025, 0.25, 0.5 and 1.0 mg of PEG-400 and the animals were sacrificed on day 5. Eyes were harvested and processed for histological analysis. In all other experiments 0.5 mg PEG was injected and animals were sacrificed on days 1, 3, 5 or 14. Paraffin, 5 μm and plastic, 1 μm and 80 nm sections were used for further analysis. Subretinal injection of 0.5 mg PEG induced a 32% reduction of outer nuclear layer (ONL) thickness, 61% decrease of photoreceptor outer and inner segment length, 49% decrease of nuclear density in the ONL and 31% increase of RPE cell density by day 5 after injection. The maximum level of TUNEL positive nuclei in the ONL (6.8 + 1.99%) was detected at day 5 after PEG injection and co-localized with Casp3act. Histological signs of apoptosis were observed in the ONL by light or electron microscopy. Degeneration of RPE cells was found in PEG injected eyes. Gene expression data identified several genes reported to be involved in human AMD. C3, Cfi, Serping1, Mmp9, Htra1 and Lpl were up-regulated in PEG injected eyes compared to PBS controls. PEG leads to morphological and gene expression changes in RPE and retina consistent with dry AMD. This model will be useful to investigate dry AMD pathogenesis and treatment.
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Affiliation(s)
- Valeriy V Lyzogubov
- Department of Ophthalmology, Jones Eye Institute, Pat & Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Nalini S Bora
- Department of Ophthalmology, Jones Eye Institute, Pat & Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Ruslana G Tytarenko
- Department of Ophthalmology, Jones Eye Institute, Pat & Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Puran S Bora
- Department of Ophthalmology, Jones Eye Institute, Pat & Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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Bora NS, Matta B, Lyzogubov VV, Bora PS. Relationship between the complement system, risk factors and prediction models in age-related macular degeneration. Mol Immunol 2014; 63:176-83. [PMID: 25074023 DOI: 10.1016/j.molimm.2014.07.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/09/2014] [Indexed: 11/27/2022]
Abstract
Studies performed over the past decade in humans and experimental animals have been a major source of information and improved our understanding of how dysregulation of the complement system contributes to age-related macular degeneration (AMD) pathology. Drusen, the hall-mark of dry-type AMD are reported to be the by-product of complement mediated inflammatory processes. In wet AMD, unregulated complement activation results in increased production of angiogenic growth factors leading to choroidal neovascularization both in humans and in animal models. In this review article we have linked the complement system with modifiable and non-modifiable AMD risk factors as well as with prediction models of AMD. Understanding the association between the complement system, risk factors and prediction models will help improve our understanding of AMD pathology and management of this disease.
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Affiliation(s)
- Nalini S Bora
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, 4301 West Markham, Little Rock, AR 72205, USA.
| | - Bharati Matta
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, 4301 West Markham, Little Rock, AR 72205, USA
| | - Valeriy V Lyzogubov
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, 4301 West Markham, Little Rock, AR 72205, USA
| | - Puran S Bora
- Department of Ophthalmology, Jones Eye Institute, Pat and Willard Walker Eye Research Center, University of Arkansas for Medical Sciences, 4301 West Markham, Little Rock, AR 72205, USA
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Ardeljan D, Wang Y, Park S, Shen D, Chu XK, Yu CR, Abu-Asab M, Tuo J, Eberhart CG, Olsen TW, Mullins RF, White G, Wadsworth S, Scaria A, Chan CC. Interleukin-17 retinotoxicity is prevented by gene transfer of a soluble interleukin-17 receptor acting as a cytokine blocker: implications for age-related macular degeneration. PLoS One 2014; 9:e95900. [PMID: 24780906 PMCID: PMC4004582 DOI: 10.1371/journal.pone.0095900] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/31/2014] [Indexed: 01/11/2023] Open
Abstract
Age-related macular degeneration (AMD) is a common yet complex retinal degeneration that causes irreversible central blindness in the elderly. Pathology is widely believed to follow loss of retinal pigment epithelium (RPE) and photoreceptor degeneration. Here we report aberrant expression of interleukin-17A (IL17A) and the receptor IL17RC in the macula of AMD patients. In vitro, IL17A induces RPE cell death characterized by the accumulation of cytoplasmic lipids and autophagosomes with subsequent activation of pro-apoptotic Caspase-3 and Caspase-9. This pathology is reduced by siRNA knockdown of IL17RC. IL17-dependent retinal degeneration in a mouse model of focal retinal degeneration can be prevented by gene therapy with adeno-associated virus vector encoding soluble IL17 receptor. This intervention rescues RPE and photoreceptors in a MAPK-dependent process. The IL17 pathway plays a key role in RPE and photoreceptor degeneration and could hold therapeutic potential in AMD.
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Affiliation(s)
- Daniel Ardeljan
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yujuan Wang
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Stanley Park
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Defen Shen
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xi Kathy Chu
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Cheng-Rong Yu
- Molecular Immunology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mones Abu-Asab
- Histology Core, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jingsheng Tuo
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Charles G. Eberhart
- Department of Pathology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Timothy W. Olsen
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States of America
| | - Robert F. Mullins
- Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Gary White
- Genzyme Corporation, Framingham, Massachusetts, United States of America
| | - Sam Wadsworth
- Genzyme Corporation, Framingham, Massachusetts, United States of America
| | - Abraham Scaria
- Genzyme Corporation, Framingham, Massachusetts, United States of America
| | - Chi-Chao Chan
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Identification of age-related macular degeneration related genes by applying shortest path algorithm in protein-protein interaction network. BIOMED RESEARCH INTERNATIONAL 2013; 2013:523415. [PMID: 24455700 PMCID: PMC3878555 DOI: 10.1155/2013/523415] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 11/27/2013] [Indexed: 12/31/2022]
Abstract
This study attempted to find novel age-related macular degeneration (AMD) related genes based on 36 known AMD genes. The well-known shortest path algorithm, Dijkstra's algorithm, was applied to find the shortest path connecting each pair of known AMD related genes in protein-protein interaction (PPI) network. The genes occurring in any shortest path were considered as candidate AMD related genes. As a result, 125 novel AMD genes were predicted. The further analysis based on betweenness and permutation test indicates that there are 10 genes involved in the formation or development of AMD and may be the actual AMD related genes with high probability. We hope that this contribution would promote the study of age-related macular degeneration and discovery of novel effective treatments.
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Pigment epithelium-derived factor reduces apoptosis and pro-inflammatory cytokine gene expression in a murine model of focal retinal degeneration. ASN Neuro 2013; 5:e00126. [PMID: 24160756 PMCID: PMC3840469 DOI: 10.1042/an20130028] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
AMD (age-related macular degeneration) is a neurodegenerative disease causing irreversible central blindness in the elderly. Apoptosis and inflammation play important roles in AMD pathogenesis. PEDF (pigment epithelium-derived factor) is a potent neurotrophic and anti-inflammatory glycoprotein that protects the retinal neurons and photoreceptors against cell death caused by pathological insults. We studied the effects of PEDF on focal retinal lesions in DKO rd8 (Ccl2−/−/Cx3cr1−/− on C57BL/6N [Crb1rd8]) mice, a model for progressive, focal rd (retinal degeneration). First, we found a significant decrease in PEDF transcript expression in DKO rd8 mouse retina and RPE (retinal pigment epithelium) than WT (wild-type, C57BL/6N). Next, cultured DKO rd8 RPE cells secreted lower levels of PEDF protein in the media than WT. Then the right eyes of DKO rd8 mice were injected intravitreously with recombinant human PEDF protein (1 μg), followed by a subconjunctival injection of PEDF (3 μg) 4 weeks later. The untreated left eyes served as controls. The effect of PEDF was assessed by fundoscopy, ocular histopathology and A2E {[2,6-dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E,7E-octatetra-enyl]-1-(2-hydroxyethyl)-4-[4-methyl-6(2,6,6-trimethyl-1-cyclohexen-1-yl) 1E,3E,5E,7E-hexatrienyl]-pyridinium} levels, as well as apoptotic and inflammatory molecules. The PEDF-treated eyes showed slower progression or attenuation of the focal retinal lesions, fewer and/or smaller photoreceptor and RPE degeneration, and significantly lower A2E, relative to the untreated eyes. In addition, lower expression of apoptotic and inflammatory molecules were detected in the PEDF-treated than untreated eyes. Our results establish that PEDF potently stabilizes photoreceptor degeneration via suppression of both apoptotic and inflammatory pathways. The multiple beneficial effects of PEDF represent a novel approach for potential AMD treatment. Apoptosis and inflammation play important roles in age-related macular degeneration. As a potent neurotrophic and anti-inflammatory glycoprotein, PEDF potently stabilizes photoreceptor degeneration via suppression of apoptotic and inflammatory pathways in a mouse model of progressive, focal rd.
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Respiratory syncytial virus G protein CX3C motif impairs human airway epithelial and immune cell responses. J Virol 2013; 87:13466-79. [PMID: 24089561 DOI: 10.1128/jvi.01741-13] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a major cause of severe lower respiratory infection in infants and young children and causes disease in the elderly and persons with compromised cardiac, pulmonary, or immune systems. Despite the high morbidity rates of RSV infection, no highly effective treatment or vaccine is yet available. The RSV G protein is an important contributor to the disease process. A conserved CX3C chemokine-like motif in G likely contributes to the pathogenesis of disease. Through this motif, G protein binds to CX3CR1 present on various immune cells and affects immune responses to RSV, as has been shown in the mouse model of RSV infection. However, very little is known of the role of RSV CX3C-CX3CR1 interactions in human disease. In this study, we use an in vitro model of human RSV infection comprised of human peripheral blood mononuclear cells (PBMCs) separated by a permeable membrane from human airway epithelial cells (A549) infected with RSV with either an intact CX3C motif (CX3C) or a mutated motif (CX4C). We show that the CX4C virus induces higher levels of type I/III interferon (IFN) in A549 cells, increased IFN-α and tumor necrosis factor alpha (TNF-α) production by human plasmacytoid dendritic cells (pDCs) and monocytes, and increased IFN-γ production in effector/memory T cell subpopulations. Treatment of CX3C virus-infected cells with the F(ab')2 form of an anti-G monoclonal antibody (MAb) that blocks binding to CX3CR1 gave results similar to those with the CX4C virus. Our data suggest that the RSV G protein CX3C motif impairs innate and adaptive human immune responses and may be important to vaccine and antiviral drug development.
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Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness in aged individuals. Recent advances have highlighted the essential role of immune processes in the development, progression and treatment of AMD. In this Review we discuss recent discoveries related to the immunological aspects of AMD pathogenesis. We outline the diverse immune cell types, inflammatory activators and pathways that are involved. Finally, we discuss the future of inflammation-directed therapeutics to treat AMD in the growing aged population.
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Joachim SC, Reinehr S, Kuehn S, Laspas P, Gramlich OW, Kuehn M, Tischoff I, von Pein HD, Dick HB, Grus FH. Immune response against ocular tissues after immunization with optic nerve antigens in a model of autoimmune glaucoma. Mol Vis 2013; 19:1804-14. [PMID: 23946635 PMCID: PMC3742127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 08/03/2013] [Indexed: 10/26/2022] Open
Abstract
PURPOSE In recent years, numerous studies have investigated the involvement of immunological mechanisms in glaucoma. Until now, it has not been determined whether the altered antibody pattern detected in patients is harmful to retinal ganglion cells (RGCs) or triggers disease formation in any way. In a model of experimental autoimmune glaucoma, RGC loss can be induced through immunization with certain ocular antigens. In the current study, the time course of the levels of autoreactivity against ocular tissues after immunization was examined. METHODS Intraocular pressure was measured regularly. Ten weeks after immunization with an optic nerve homogenate antigen (ONA), the number of RGCs was determined. Immunoglobulin G levels in aqueous humor were measured via enzyme-linked immunosorbent assay at the same time point. Serum from different time points was used to analyze the possible occurrence of autoreactive antibodies against the retina or optic nerve in this autoimmune glaucoma model. Additionally, optic nerve and brain sections were evaluated for possible pathological findings. RESULTS Intraocular pressure stayed within the normal range throughout this study. A continuous increase of autoreactive antibodies against the optic nerve and retina sections was observed. At 4, 6, and 10 weeks, antibody reactivity was significantly higher in ONA animals (p<0.01). Aqueous humor immunoglobulin G levels were also significantly higher in the ONA group (p=0.006). Ten weeks after immunization, significantly fewer RGCs were noted in the ONA group (p=0.00003). The optic nerves from ONA animals exhibited damaged axons. No pathological findings appeared in any brain sections. CONCLUSIONS Our findings suggest that these modified antibodies play a substantial role in mechanisms leading to RGC death. The slow dissolution of RGCs observed in animals with autoimmune glaucoma is comparable to the slow progressive RGC loss in glaucoma patients, thus making this a useful model to develop neuroprotective therapies in the future.
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Affiliation(s)
- Stephanie C. Joachim
- Experimental Eye Research Institute, Ruhr University Eye Hospital, Bochum, Germany
| | - Sabrina Reinehr
- Experimental Eye Research Institute, Ruhr University Eye Hospital, Bochum, Germany
| | - Sandra Kuehn
- Experimental Eye Research Institute, Ruhr University Eye Hospital, Bochum, Germany
| | - Panagiotis Laspas
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Oliver W. Gramlich
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Mathias Kuehn
- Experimental Eye Research Institute, Ruhr University Eye Hospital, Bochum, Germany
| | - Iris Tischoff
- Institute of Pathology, Ruhr University, Bochum, Germany
| | - Harald D. von Pein
- Department of Neuropathology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - H. Burkhard Dick
- Experimental Eye Research Institute, Ruhr University Eye Hospital, Bochum, Germany
| | - Franz H. Grus
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
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Ramkumar HL, Tuo J, Shen DF, Zhang J, Cao X, Chew EY, Chan CC. Nutrient supplementation with n3 polyunsaturated fatty acids, lutein, and zeaxanthin decrease A2E accumulation and VEGF expression in the retinas of Ccl2/Cx3cr1-deficient mice on Crb1rd8 background. J Nutr 2013; 143:1129-35. [PMID: 23677863 PMCID: PMC3681547 DOI: 10.3945/jn.112.169649] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The Age-Related Eye Diseases Study 2 (AREDS2) clinical trial is assessing the effects of higher dietary xanthophyll (lutein and zeaxanthin) and long-chain n3 polyunsaturated fatty acid (LCPUFA) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) intake on progression to advanced age-related macular degeneration (AMD). This study's purpose was to examine the retinal effects of the AREDS2 formulation on Chemokine (C-C motif) ligand 2 (Ccl2(-/-))/CX3C chemokine receptor 1 (Cx3cr1(-/-)) mice on Crumbs homolog 1 retinal degeneration phenotype 8 (Crb1(rd8)) background (DKO), which develop focal retinal lesions with certain features similar to AMD. DKO and C57BL/6N rd8 background mice (WT) were bred and randomized into 4 groups. Two groups, WT mice on AREDS2 diet (A-WT) and DKO mice on AREDS2 diet (A-DKO), were supplemented daily with 1.76 μmol of lutein, 35.1 μmol of zeaxanthin, 215 μmol EPA, and 107 μmol of DHA, and 2 control groups, WT mice on control diet (C-WT) and DKO mice on control diet (C-DKO), were fed an isocaloric diet. All mice had monthly fundus photos and were killed after 3 mo for biochemical and histologic analyses. After 3 mo, 81% of A-DKO mice had lesion regression compared with 25% of C-DKO mice (P < 0.05). Toxic retinal 2-[2,6-dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E,7E-octatetra-enyl]-1-(2-hydroxyethyl)-4-[4-methyl-6(2,6,6-trimethyl-1-cyclohexen-1-yl) 1E,3E,5E,7E-hexatrienyl]-pyridinium (A2E) concentrations were significantly lower in A-DKO compared with C-DKO mice. The outer nuclear layer thickness in A-DKO mice was significantly greater than that in C-DKO mice. Retinal expression of inducible nitric oxide synthase (iNos) tumor necrosis factor-α (Tnf-α), Cyclooxygenase-2 (Cox-2), interleukin1beta (IL-1β), and vascular endothelial growth factor (Vegf) was significantly lower in A-DKO compared with C-DKO mice. Xanthophylls and LCPUFAs have antiinflammatory, neuroprotective, and antiangiogenic properties. Our data provide potential mechanisms by which the AREDS2 formula has a protective effect on retinal lesions in DKO mice.
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Affiliation(s)
- Hema L. Ramkumar
- Laboratory of Immunology,Howard Hughes Medical Institute, Chevy Chase, MD,Department of Ophthalmology, Shiley Eye Center, University of California-San Diego, San Diego, CA
| | | | | | | | - Xiaoguang Cao
- Laboratory of Immunology,Department of Ophthalmology, Peking University People’s Hospital, Beijing, China
| | - Emily Y. Chew
- Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Chi-Chao Chan
- Laboratory of Immunology,Histology Core, and,To whom correspondence should be addressed. E-mail:
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Zhang J, Tuo J, Cao X, Shen D, Li W, Chan CC. Early degeneration of photoreceptor synapse in Ccl2/Cx3cr1-deficient mice on Crb1(rd8) background. Synapse 2013; 67:515-31. [PMID: 23592324 DOI: 10.1002/syn.21674] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 04/03/2013] [Indexed: 12/13/2022]
Abstract
Photoreceptor ribbon synapse releases glutamate to postsynaptic targets. The synaptic ribbon may play multiple roles in ribbon synapse development, synaptic vesicle recycling, and synaptic transmission. Age-related macular degeneration (AMD) patients appear to have fewer or no detectable synaptic ribbons as well as abnormal swelling in the photoreceptor terminals in the macula. However, reports on changes of photoreceptor synapses in AMD are scarce and photoreceptor type and quantity affected in early AMD is still unclear. Here, we employed multiple anatomical techniques to investigate these questions in Ccl2⁻/⁻/Cx3cr1⁻/⁻ mouse on Crb1(rd8) background (DKO rd8) at one month of age. We found that approximately 17% of photoreceptors over the focal lesion were lost. Immunostaining for synapse-associated proteins (CtBP2, synaptophysin, and vesicular glutamate transporter 1) showed significantly reduced expression and ectopic localization. Cone opsins demonstrated dramatic reduction in expression (S-opsins) and extensive mislocalization (M-opsins). Quantitative ultrastructural analysis confirmed a significant decrease in the number of cone terminals and nuclei, numerous vacuoles in remaining cone terminals, reduction in the number of synaptic ribbons in photoreceptor terminals, and ectopic rod ribbon synapses. In addition, glutamate receptor immunoreactivity on aberrant sprouting of rod bipolar cells and horizontal cells were identified at the ectopic synapses. These results indicate that synaptic alterations occur at the early stages of disease and cones are likely more susceptible to damage caused by DKO rd8 mutation. They provide a new insight into potential mechanism of vision function lost due to synaptic degeneration before cell death in the early stages of AMD.
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Affiliation(s)
- Jun Zhang
- Histology Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Chu XK, Wang Y, Ardeljan D, Tuo J, Chan CC. Controversial view of a genetically altered mouse model of focal retinal degeneration. Bioengineered 2012. [PMID: 23196746 PMCID: PMC3669152 DOI: 10.4161/bioe.22949] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Tuo et al. (2012) demonstrated tumor necrosis factor-inducible gene 6 recombinant protein (TSG-6) arrest of focal retinal lesions on a Ccl2 and Cx3cr1 double deficient mouse (DKO) on rd8 background (hereon referred to as DKO rd8). DKO rd8, a model of focal retinal degeneration with earlier onset and higher penetrance than Ccl2 and Cx3cr1 single knockout strains, demonstrates characteristic features of AMD such as focal photoreceptor atrophy, retinal pigmented epithelium (RPE) degeneration, elevated ocular A2E levels and complement deposition in addition to retinal dystrophy. The discovery of the accidently introduced Crb1 mutation (rd8) in the C57BL/6N strain has led to the recent opinion that DKO rd8 is not a model of AMD but solely a model of Crb1‑associated retinal degeneration. Differences between DKO rd8 and Crb1rd8 photoreceptor and RPE pathology, as well as increased A2E and immune dysfunction, show that DKO rd8 recapitulates some AMD‑like features in addition to rd8 retinal dystrophy. The appearance of rd8 lesions and Ccl2/Cx3cr1 lesions and the amelioration of most Ccl2/Cx3cr1 lesions in intervention studies show DKO rd8 to be a useful and appropriate model for therapeutic compound screening, such as the case with anti-inflammatory TSG‑6.
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Affiliation(s)
- Xi K Chu
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Adamus G, Wang S, Kyger M, Worley A, Lu B, Burrows GG. Systemic immunotherapy delays photoreceptor cell loss and prevents vascular pathology in Royal College of Surgeons rats. Mol Vis 2012; 18:2323-37. [PMID: 22977300 PMCID: PMC3441155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 09/04/2012] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Degenerative retinopathies, including retinitis pigmentosa, age-related retinal degeneration, autoimmune retinopathy, and related diseases affect millions of people around the world. Currently, there is no effective treatment for most of those diseases. We investigated systemic recombinant T-cell receptor ligand (RTL) immunotherapy for preventing retinal degeneration and vascular damage in the Royal College of Surgeons (RCS) rat model of retinal degeneration. METHODS RCS rats were treated with RTL220 tethered to interphotoreceptor retinoid binding protein (IRBP) peptide or control RTL101 without peptide by subcutaneous administration starting at the onset of photoreceptor degeneration or after the degenerative process began daily or every other day and performed for a 13-week period. The retinal cross sections and whole mounts were prepared to determine histopathology, leaking vessels, and formation of vascular complexes. Immunofluorescent studies evaluated microglia and monocyte chemoattractant protein-1 chemokine in treated retinas. Optokinetic studies were performed to determine visual acuity. RESULTS Systemic treatment with RTL220 prevented decreases in outer nuclear layer (ONL) thickness and showed a significantly higher number of nuclei than control rats treated with RTL101 or vehicle. RTL220 was also effective in protecting retinal vasculature from leakage and the formation of abnormal vascular complexes even when the treatment was administered after the degenerative process was initiated. Visual acuity measurement showed that rats treated with RTL220 performed significantly better than those with RTL101 and untreated age-matched controls at P60 and P90. Biodistribution studies showed that RTL220 cleared slowly from the administration site. Moreover, RTL220-treated retinas had a significantly reduced number of activated microglia in the subretinal space, decreased monocyte chemoattractant protein-1 production in the retina, inhibited T-cell responses, and reduced anti-interphotoreceptor retinoid binding protein autoantibody titers. Treatment with the control RTL101 (without a specific peptide tethered) or vehicle alone did not inhibit microglia activation or protect photoreceptors or vasculature. CONCLUSIONS RTL therapy augmented photoreceptor cell survival, protected vasculature, and increased visual function in the RTL rat. Targeting chronic autoimmunity with RTLs can be an effective therapeutic alternative in delaying retinal degeneration. Subcutaneous delivery of RTLs alone or combined with other drugs could be an attractive option for long-term therapy for retinal degenerative diseases.
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Affiliation(s)
- Grazyna Adamus
- Ocular Immunology Laboratory, Casey Eye Institute, Oregon Health & Science University, Portland, OR
| | - Shaomei Wang
- Ocular Immunology Laboratory, Casey Eye Institute, Oregon Health & Science University, Portland, OR
| | - Madison Kyger
- Ocular Immunology Laboratory, Casey Eye Institute, Oregon Health & Science University, Portland, OR
| | - Aneta Worley
- Ocular Immunology Laboratory, Casey Eye Institute, Oregon Health & Science University, Portland, OR
| | - Bin Lu
- Ocular Immunology Laboratory, Casey Eye Institute, Oregon Health & Science University, Portland, OR
| | - Gregory G. Burrows
- Tykeson MS Research Laboratory, Department of Neurology, Oregon Health & Science University, Portland, OR,Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR
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Joachim SC, Gramlich OW, Laspas P, Schmid H, Beck S, von Pein HD, Dick HB, Pfeiffer N, Grus FH. Retinal ganglion cell loss is accompanied by antibody depositions and increased levels of microglia after immunization with retinal antigens. PLoS One 2012; 7:e40616. [PMID: 22848388 PMCID: PMC3406064 DOI: 10.1371/journal.pone.0040616] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 06/11/2012] [Indexed: 12/25/2022] Open
Abstract
Background Antibodies against retinal and optic nerve antigens are detectable in glaucoma patients. Recent studies using a model of experimental autoimmune glaucoma demonstrated that immunization with certain ocular antigens causes an immun-mediated retinal ganglion cell loss in rats. Methodology/Principal Findings Rats immunized with a retinal ganglion cell layer homogenate (RGA) had a reduced retinal ganglion cell density on retinal flatmounts (p = 0.007) and a lower number of Brn3+retinal ganglion cells (p = 0.0001) after six weeks. The autoreactive antibody development against retina and optic nerve was examined throughout the study. The levels of autoreactive antibodies continuously increased up to 6 weeks (retina: p = 0.004; optic nerve: p = 0.000003). Additionally, antibody deposits were detected in the retina (p = 0.02). After 6 weeks a reactive gliosis (GFAP density: RGA: 174.7±41.9; CO: 137.6±36.8, p = 0.0006; %GFAP+ area: RGA: 8.5±3.4; CO: 5.9±3.6, p = 0.006) as well as elevated level of Iba1+ microglia cells (p = 0.003) was observed in retinas of RGA animals. Conclusions/Significance Our findings suggest that these antibodies play a substantial role in mechanisms leading to retinal ganglion cell death. This seems to lead to glia cell activation as well as the invasion of microglia, which might be associated with debris clearance.
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Affiliation(s)
- Stephanie C Joachim
- Experimental Eye Research Institute, Ruhr University Eye Hospital, Bochum, Germany.
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Pennesi ME, Neuringer M, Courtney RJ. Animal models of age related macular degeneration. Mol Aspects Med 2012; 33:487-509. [PMID: 22705444 DOI: 10.1016/j.mam.2012.06.003] [Citation(s) in RCA: 271] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Age related macular degeneration (AMD) is the leading cause of vision loss of those over the age of 65 in the industrialized world. The prevalence and need to develop effective treatments for AMD has lead to the development of multiple animal models. AMD is a complex and heterogeneous disease that involves the interaction of both genetic and environmental factors with the unique anatomy of the human macula. Models in mice, rats, rabbits, pigs and non-human primates have recreated many of the histological features of AMD and provided much insight into the underlying pathological mechanisms of this disease. In spite of the large number of models developed, no one model yet recapitulates all of the features of human AMD. However, these models have helped reveal the roles of chronic oxidative damage, inflammation and immune dysregulation, and lipid metabolism in the development of AMD. Models for induced choroidal neovascularization have served as the backbone for testing new therapies. This article will review the diversity of animal models that exist for AMD as well as their strengths and limitations.
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Affiliation(s)
- Mark E Pennesi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
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Differential modulation of retinal degeneration by Ccl2 and Cx3cr1 chemokine signalling. PLoS One 2012; 7:e35551. [PMID: 22545116 PMCID: PMC3335860 DOI: 10.1371/journal.pone.0035551] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 03/21/2012] [Indexed: 12/15/2022] Open
Abstract
Microglia and macrophages are recruited to sites of retinal degeneration where local cytokines and chemokines determine protective or neurotoxic microglia responses. Defining the role of Ccl2-Ccr2 and Cx3cl1-Cx3cr1 signalling for retinal pathology is of particular interest because of its potential role in age-related macular degeneration (AMD). Ccl2, Ccr2, and Cx3cr1 signalling defects impair macrophage trafficking, but have, in several conflicting studies, been reported to show different degrees of age-related retinal degeneration. Ccl2/Cx3cr1 double knockout (CCDKO) mice show an early onset retinal degeneration and have been suggested as a model for AMD. In order to understand phenotypic discrepancies in different chemokine knockout lines and to study how defects in Ccl2 and/or Cx3cr1 signalling contribute to the described early onset retinal degeneration, we defined primary and secondary pathological events in CCDKO mice. To control for genetic background variability, we compared the original phenotype with that of single Ccl2, Cx3cr1 and Ccl2/Cx3cr1 double knockout mice obtained from backcrosses of CCDKO with C57Bl/6 mice. We found that the primary pathological event in CCDKO mice develops in the inferior outer nuclear layer independently of light around postnatal day P14. RPE and vascular lesions develop secondarily with increasing penetrance with age and are clinically similar to retinal telangiectasia not to choroidal neovascularisation. Furthermore, we provide evidence that a third autosomal recessive gene causes the degeneration in CCDKO mice and in all affected re-derived lines and subsequently demonstrated co-segregation of the naturally occurring RD8 mutation in the Crb1 gene. By comparing CCDKO mice with re-derived CCl2(-/-)/Crb1(Rd8/RD8), Cx3cr1(-/-)/Crb1(Rd8/RD8) and CCl2(-/-)/Cx3cr1(-/-)/Crb1(Rd8/RD8) mice, we observed a differential modulation of the retinal phenotype by genetic background and both chemokine signalling pathways. These findings indicate that CCDKO mice are not a model of AMD, but a model for an inherited retinal degeneration that is differentially modulated by Ccl2-Ccr2 and Cx3cl1-Cx3cr1 chemokine signalling.
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Zhang M, Xu G, Liu W, Ni Y, Zhou W. Role of fractalkine/CX3CR1 interaction in light-induced photoreceptor degeneration through regulating retinal microglial activation and migration. PLoS One 2012; 7:e35446. [PMID: 22536384 PMCID: PMC3334900 DOI: 10.1371/journal.pone.0035446] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 03/16/2012] [Indexed: 12/15/2022] Open
Abstract
Background Excessive exposure to light enhances the progression and severity of some human retinal degenerative diseases. While retinal microglia are likely to be important in neuron damage associated with these diseases, the relationship between photoreceptor damage and microglial activation remains poorly understood. Some recent studies have indicated that the chemokine fractalkine is involved in the pathogenesis of many neurodegenerative diseases. The present study was performed to investigate the cross-talk between injured photoreceptors and activated retinal microglia, focusing on the role of fractalkine and its receptor CX3CR1 in light-induced photoreceptor degeneration. Methodology/Principal Findings Both in vivo and in vitro experiments were involved in the research. In vivo, Sprague–Dawley rats were exposed to blue light for 24 hours. In vitro, the co-culture of primary retinal microglia and a photoreceptor cell line (661W cell) was exposed to blue light for five hours. Some cultures were pretreated by the addition of anti-CX3CR1 neutralizing antibody or recombinant fractalkine. Expression of fractalkine/CX3CR1 and inflammatory cytokines was detected by immunofluorescence, real-time PCR, Western immunoblot analysis, and ELISA assay. TUNEL method was used to detect cell apoptosis. In addition, chemotaxis assay was performed to evaluate the impact of soluble fractalkine on microglial migration. Our results showed that the expression of fractalkine that was significantly upregulated after exposure to light, located mainly at the photoreceptors. The extent of photoreceptor degeneration and microglial migration paralleled the increased level of fractalkine/CX3CR1. Compared with the control, the expression of inflammatory cytokines was significantly downregulated in the anti-CX3CR1 neutralizing antibody-treated group, and the number of photoreceptors was also well preserved. The addition of recombinant full-length fractalkine or soluble fractalkine resulted in fewer TUNEL-positive photoreceptors and an increased number of migratory microglia respectively. Conclusions/Significance These findings demonstrate that fractalkine/CX3CR1 interaction may play an important role in the photoreceptor-microglia cross-talk in light-induced photoreceptor degeneration.
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Affiliation(s)
- Meng Zhang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Gezhi Xu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
- Institute of Brain Science, Fudan University, Shanghai, People's Republic of China
- State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, People's Republic of China
- * E-mail:
| | - Wei Liu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Yingqin Ni
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
| | - Wenting Zhou
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
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Tuo J, Cao X, Shen D, Wang Y, Zhang J, Oh JY, Prockop DJ, Chan CC. Anti-inflammatory recombinant TSG-6 stabilizes the progression of focal retinal degeneration in a murine model. J Neuroinflammation 2012; 9:59. [PMID: 22452753 PMCID: PMC3359240 DOI: 10.1186/1742-2094-9-59] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 03/27/2012] [Indexed: 02/06/2023] Open
Abstract
Background Inflammatory responses are detected in the retina of patients with age-related macular degeneration and Ccl2-/-/Cx3cr1-/- mice on rd8 background,(Ccl2-/-/Cx3cr1-/- mice) a model that develops progressive age-related macular degeneration-like retinal lesions including focal photoreceptor degeneration, abnormal retinal pigment epithelium and A2E accumulation. Tumor necrosis factor-inducible gene 6 protein is an anti-inflammatory protein and has been shown to improve myocardial infarction outcome and chemically injured cornea in mice by suppressing inflammation. In this study, we evaluated the effect of an intravitreous injection of recombinant TSG-6 on the retinal lesions of Ccl2-/-/Cx3cr1-/- mice. Methods Recombinant TSG-6 (400 ng) was administered by intravitreous injection into the right eye of six-week-old Ccl2-/-/Cx3cr1-/- mice. Their left eye was injected with phosphate-buffered saline as a control. Funduscopic pictures were taken before injection and sequentially once a month after injection. The mice were killed two months after injection and the ocular histology examined. Retinal A2E, a major component of lipofuscin, was measured by high performance liquid chromatography. The microarray of ocular mRNA of 92 immunological genes was performed. The genes showing differentiated expression in microarray were further compared between the injected right eye and the contralateral (control) eye by [real-time quantitative reverse transcription polymerase chain reaction] qRT-PCR. Results The continuous monitoring of the fundus for two months showed a slower progression or alleviation of retinal lesions in the treated right eyes as compared with the untreated left eyes. Among 23 pairs of eyes, the lesion levels improved in 78.3%, stayed the same in 8.7% and progressed in 13.0%. Histology confirmed the clinical observation. Even though there was no difference in the level of A2E between the treated and the untreated eyes, microarray analysis of 92 immune genes showed that IL-17a was substantially decreased after the treatment. Expression of TNF-α showed a similar pattern to IL-17a. The results were consistent in duplicated arrays and confirmed by qRT-PCR. Conclusions We concluded that intravitreous administration of recombinant TSG-6 might stabilize retinal lesions in Ccl2-/-/Cx3cr1-/- mice on rd8 background. Modulation of ocular immunological gene expressions, especially IL-17a, could be one of the mechanisms.
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Affiliation(s)
- Jingsheng Tuo
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Kramer M, Hasanreisoglu M, Feldman A, Axer-Siegel R, Sonis P, Maharshak I, Monselise Y, Gurevich M, Weinberger D. Monocyte chemoattractant protein-1 in the aqueous humour of patients with age-related macular degeneration. Clin Exp Ophthalmol 2012; 40:617-25. [PMID: 22172228 DOI: 10.1111/j.1442-9071.2011.02747.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND To investigate the role of inflammation in age-related macular degeneration by measuring the levels of cytokines in the aqueous humour. METHODS Samples of aqueous humour were collected from 34 patients with age-related macular degeneration and 16 age-matched control subjects undergoing cataract surgery. Age-related macular degeneration stage was determined clinically, before surgery. Levels of cytokines were measured using Luminex X-MAP technology, and positive results were verified by Western blot. RESULTS Age-related macular degeneration was moderate in 18 patients and advanced in 16. The advanced age-related macular degeneration group was further divided into patients with active choroidal neovascularization (n = 7), disciform scar (n = 7) or central geographic atrophy (n = 2). Higher-than-normal levels of monocyte chemoattractant protein-1 in the aqueous humour were associated with advanced age-related macular degeneration (200 ± 140 pg/mL vs. 100 ± 61 pg/mL; P = 0.03), especially active choroidal neovascularization (255 ± 155 pg/mL; P = 0.02), Western blot analysis verified the monocyte chemoattractant protein-1 findings. Patients with disciform scar showed a trend of abnormally high levels of interleukin-12 (p70) (1.7 ± 2.4 pg/mL vs. 0.2 ± 1 pg/mL; P = 0.07), tumour necrosis factor-α (1.8 ± 2.4 pg/mL vs. 0.3 ± 1 pg/mL; P = 0.06) and interleukin-12 (4.7 ± 6.4 pg/mL vs. 1.2 ± 2.1 pg/mL; P = 0.08). CONCLUSION Elevated levels of inflammation-related cytokines in the aqueous humour in various stages of age-related macular degeneration may suggest a pathogenic role of inflammation. Monocyte chemoattractant protein-1 may be indicative of the angiogenic phase. Further corroborative studies are required.
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Affiliation(s)
- Michal Kramer
- Department of Ophthalmology, Laboratory of Clinical Immunology, Rabin Medical Center, Petach Tikva, Israel.
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Tuo J, Pang JJ, Cao X, Shen D, Zhang J, Scaria A, Wadsworth SC, Pechan P, Boye SL, Hauswirth WW, Chan CC. AAV5-mediated sFLT01 gene therapy arrests retinal lesions in Ccl2(-/-)/Cx3cr1(-/-) mice. Neurobiol Aging 2012; 33:433.e1-10. [PMID: 21397984 PMCID: PMC3136657 DOI: 10.1016/j.neurobiolaging.2011.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 01/08/2011] [Accepted: 01/26/2011] [Indexed: 12/18/2022]
Abstract
To test the effects of adeno-associated virus encoding sFLT01 (AAV5.sFLT01) on the retinal lesions in Ccl2(-/-)/Cx3cr1(-/-) mice, a model for age-related macular degeneration (AMD), AAV5.sFLT01 was injected into the subretinal space of the right eyes and the left eyes served as controls. Histology found no retinal toxicity due to the treatment after 3 months. The treated eyes showed lesion arrest compared with lesion progression in the left eyes by fundus monitoring monthly and histological evaluation 3 months after treatment. Retinal ultrastructure showed fewer lipofuscin and better preserved photoreceptors after the treatment. A2E, a major component of lipofuscin, was lower in the treated eyes than in the control eyes. Molecular analysis showed that AAV5.sFLT01 lowered retinal extracellular signal-regulated kinase (ERK) phosphorylation and inducible nitric oxide synthetase expression, which suggested the involvement of reactive nitrogen species in the retinal lesions of Ccl2(-/-)/Cx3cr1(-/-). We concluded that local delivery of AAV5.sFLT01 can stabilize retinal lesions in Ccl2(-/-)/Cx3cr1(-/-) mice. The findings provide further support for the potential beneficial effects of sFLT01 gene therapy for age-related macular degeneration.
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Affiliation(s)
- Jingsheng Tuo
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, NIH, Bethesda, MD
| | | | - Xiaoguang Cao
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, NIH, Bethesda, MD
- Department of Ophthalmology, People’s Hospital, Beijing University, Beijing, China
| | - Defen Shen
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, NIH, Bethesda, MD
| | - Jun Zhang
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, NIH, Bethesda, MD
| | - Abraham Scaria
- Department of Molecular Biology, Genzyme Corporation, Framingham, MA
| | | | - Peter Pechan
- Department of Molecular Biology, Genzyme Corporation, Framingham, MA
| | - Sanford L. Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL
| | | | - Chi-Chao Chan
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, NIH, Bethesda, MD
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Zhou Y, Sheets KG, Knott EJ, Regan CE, Tuo J, Chan CC, Gordon WC, Bazan NG. Cellular and 3D optical coherence tomography assessment during the initiation and progression of retinal degeneration in the Ccl2/Cx3cr1-deficient mouse. Exp Eye Res 2011; 93:636-48. [PMID: 21854772 DOI: 10.1016/j.exer.2011.07.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 07/11/2011] [Accepted: 07/28/2011] [Indexed: 12/13/2022]
Abstract
Retinal pathologies common to human eye diseases, including abnormal retinal pigment epithelial (RPE) cells, drusen-like accumulation, photoreceptor atrophy, and choroidal neovascularization, have been reported in the Ccl2/Cx3cr1-deficient mouse. The Ccl2 gene encodes the pro-inflammatory chemokine CCL2 (MCP-1), which is responsible for chemotactic recruitment of monocyte-derived macrophages to sites of inflammation. The Cx3cr1 gene encodes the fractalkine receptor, CX3CR1, and is required for accumulation of monocytes and microglia recruited via CCL2. Chemokine-mediated inflammation is implicated in retinal degenerative diseases such as diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, and uveoretinitis, and proper chemokine signaling from the RPE, Müller glia, and astrocytes is necessary to regulate leukocyte trafficking. Therefore, this mouse, possessing aberrant chemokine signaling coupled with retinal degenerative pathologies, presents an ideal opportunity to investigate the effect of altered signaling on retinal homeostasis and photoreceptor degeneration. Since this mouse is a recent development, more data covering the onset, location, and progression rate of pathologies is needed. In the present study we establish these parameters and show two photoreceptor cell death processes. Our observations of decreased glutamine synthetase and increased glial fibrillary acidic protein suggest that Müller cells respond very early within regions where lesions are forming. Finally, we suggest that retinal angiomatous proliferation contributes to pathological angiogenesis in this Ccl2/Cx3cr1-deficient mouse.
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Affiliation(s)
- Yongdong Zhou
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, School of Medicine, New Orleans, LA 70112, USA
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Buschini E, Piras A, Nuzzi R, Vercelli A. Age related macular degeneration and drusen: neuroinflammation in the retina. Prog Neurobiol 2011; 95:14-25. [PMID: 21740956 DOI: 10.1016/j.pneurobio.2011.05.011] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/03/2011] [Accepted: 05/09/2011] [Indexed: 12/19/2022]
Abstract
Inflammation protects from dangerous stimuli, restoring normal tissue homeostasis. Inflammatory response in the nervous system ("neuroinflammation") has distinct features, which are shared in several diseases. The retina is an immune-privileged site, and the tight balance of immune reaction can be disrupted and lead to age-related macular disease (AMD) and to its peculiar sign, the druse. Excessive activation of inflammatory and immunological cascade with subsequent induction of damage, persistent activation of resident immune cells, accumulation of byproducts that exceeds the normal capacity of clearance giving origin to a chronic local inflammation, alterations in the activation of the complement system, infiltration of macrophages, T-lymphocytes and mast-cells from the bloodstream, participate in the mechanisms which originate the drusen. In addition, aging of the retina and AMD involve also para-inflammation, by which immune cells react to persistent stressful stimuli generating low-grade inflammation, aimed at restoring function and maintaining tissue homeostasis by varying the set point in relation to the new altered conditions. This mechanism is also seen in the normal aging retina, but, in the presence of noxious stimuli as in AMD, it can become chronic and have an adverse outcome. Finally, autophagy may provide new insights to understand AMD pathology, due to its contribution in the removal of defective proteins. Therefore, the AMD retina can represent a valuable model to study neuroinflammation, its mechanisms and therapy in a restricted and controllable environment. Targeting these pathways could represent a new way to treat and prevent both exudative and dry forms of AMD.
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Affiliation(s)
- Elisa Buschini
- NICO, Neuroscience Institute of the Cavalieri Ottolenghi Foundation, University of Torino, Regione Gonzole 10, Orbassano (TO), Italy.
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Shen D, Cao X, Zhao L, Tuo J, Wong WT, Chan CC. Naloxone ameliorates retinal lesions in Ccl2/Cx3cr1 double-deficient mice via modulation of microglia. Invest Ophthalmol Vis Sci 2011; 52:2897-904. [PMID: 21245403 DOI: 10.1167/iovs.10-6114] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PURPOSE The role of naloxone, an opioid receptor antagonist, on microglial inhibition and neuroprotective effects has been reported in lipopolysaccharide (LPS)-induced neurodegeneration and light-induced photoreceptor degeneration. The authors evaluated the effects of naloxone on Ccl2(-/-)/Cx3cr1(-/-) (DKO) mice, a murine model of age-related macular degeneration (AMD). METHODS Two-month-old DKO and wild-type controls were given daily intraperitoneal injections of naloxone or PBS for 2 months. Animals were examined monthly by funduscopy. Ocular tissue was analyzed histologically and in retinal flat mount preparations. Ocular A2E was measured using HPLC. Quantitative RT-PCR analyzed TNF-α, IL-1β, IL-10 and TLR4 transcripts in the DKO eyes and LPS activated culture microglial cells. Serum nitrite was measured using Griess colorimetric reaction. RESULTS Naloxone ameliorated the clinical progression and severity of retinal lesions in the DKO mice compared with those of untreated controls. Histopathology also showed less focal retinal degeneration in the treated DKO mice than in controls. The aggregation of microglia in the outer retina in DKO mice was significantly reduced in naloxone-treated animals compared with control untreated DKO. Ocular TNF-α, IL-1β, and TLR4 transcripts and A2E were significantly lower in naloxone-treated DKO animals and cultured microglial cells than in controls, as were serum nitrite levels. CONCLUSIONS Naloxone significantly reduces the progress of retinal lesions in DKO mice. Naloxone modulates microglia accumulation and activation at the site of retinal degeneration, which may be mediated by inhibition of the proinflammatory molecules of NO, TNF-α, and IL-β. The potential therapeutic effects of naloxone on retinal degeneration, including AMD, warrants further investigation.
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Affiliation(s)
- Defen Shen
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-1857, USA
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Lin Q, Yang XP, Fang D, Ren X, Zhou H, Fang J, Liu X, Zhou S, Wen F, Yao X, Wang JM, Su SB. High-mobility group box-1 mediates toll-like receptor 4-dependent angiogenesis. Arterioscler Thromb Vasc Biol 2011; 31:1024-32. [PMID: 21372296 DOI: 10.1161/atvbaha.111.224048] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Inflammation is closely linked to angiogenesis, and Toll-like receptors (TLRs) are the key mediators of inflammatory responses. However, the impact of TLRs on angiogenesis is incompletely understood. In this study, we determined the involvement of TLRs in angiogenesis. METHODS AND RESULTS In a mouse model of alkali-induced corneal neovascularization (CNV), we found that CNV was attenuated in TLR4-/- but not TLR2-/- mice. Further study revealed that the absence of TLR4 led to decreased production of proangiogenic factors in association with reduced accumulation of macrophages at the site of wounds, which was associated with reduced expression of high-mobility group box-1 (HMGB1) protein, an endogenous ligand for TLR4. Topical application of HMGB1 to the injured cornea promoted CNV with increased macrophage accumulation in wild-type mice but not in TLR4-/- mice. HMGB1 treatment in vitro also promoted the production of proangiogenic factors by mouse macrophages in a TLR4-dependent manner. Furthermore, antagonists of HMGB1 and TLR4 reduced CNV and macrophage recruitment in the injured cornea of wild-type mice. CONCLUSIONS Our results suggest that the release of HMGB1 in the wounds initiates TLR4-dependent responses that contribute to neovascularization. Thus, targeting HMGB1-TLR4 signaling cascade may constitute a novel therapeutic approach to angiogenesis-related diseases.
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Affiliation(s)
- Qing Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 S Xianlie Rd, Guangzhou 510060, China
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Gramlich OW, Joachim SC, Gottschling PF, Laspas P, Cuny CS, Pfeiffer N, Grus FH. Ophthalmopathology in rats with MBP-induced experimental autoimmune encephalomyelitis. Graefes Arch Clin Exp Ophthalmol 2011; 249:1009-20. [PMID: 21344308 DOI: 10.1007/s00417-011-1633-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/05/2011] [Accepted: 01/27/2011] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Multiple studies indicate that T-cells play a major role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis, but recently an involvement of antibodies has also been discussed. The aim of our study was to examine the effects of myelin basic protein (MBP) immunization on survival of neurons, alteration of antibody reactivity, and microglia in the retinal ganglion cell layer. METHODS EAE was induced in rats by immunization with MBP. Intraocular pressure (IOP) measurements and funduscopies were performed regularly. Neuron cell density was evaluated on cresyl-stained retinal flatmounts. IgG antibody deposition and activated microglia were detected in retina and optic nerve sections via immunohistology. The intensity of autoreactive IgG antibodies was quantified in successive serum samples via tissue arrays. RESULTS Significant loss of neurons was detected 6 weeks after immunization (p < 0.05). At the same time, IgG antibody deposits accumulated in the retina and the optic nerve of EAE animals and a significant microglia turn-over to activation was observed. The level of IgG antibody reactivity against retina and optic nerve tissue continuously increased (p < 0.05). While clinical parameters indicated typical EAE progression, we observed no changes in IOP (p > 0.9) or abnormalities in fundi. CONCLUSIONS Immunization with MBP not only causes neuron loss in the retinal ganglion cell layer, but also triggers antibody reactivity against ocular tissue. Possibly some of these antibodies are involved in the induction of neuronal apoptosis. This study suggests that, apart from T-cell mediation, alteration of antibody reactivity and activated microglia do also influence the ocular pathomechanisms in the EAE model.
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Affiliation(s)
- Oliver W Gramlich
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstraße 1, 55101, Mainz, Germany
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Dvoriantchikova G, Barakat DJ, Hernandez E, Shestopalov VI, Ivanov D. Toll-like receptor 4 contributes to retinal ischemia/reperfusion injury. Mol Vis 2010; 16:1907-12. [PMID: 21031135 PMCID: PMC2956702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 09/27/2010] [Indexed: 11/21/2022] Open
Abstract
PURPOSE We investigated whether retinal ischemia and inflammation produced by raising the intraocular pressure above normal systolic levels differs in mice that lack a functional toll-like receptor 4 (Tlr4) signaling pathway. METHODS In this work we used the murine strain B6.B10ScN-Tlr4(lps-del)/JthJ, which does not express functional Tlr4. C57BL/6J was considered as the control. We induced retinal ischemia by unilateral elevation of intraocular pressure for 1 h by direct corneal cannulation. The changes in expression of proinflammatory genes 24 h postreperfusion were assessed by quantitative PCR. Corresponding changes in protein abundances were analyzed by western blot and immunohistochemistry. Cell death was evaluated by direct counting of neurons in the ganglion cell layer of flat-mounted retinas seven days postreperfusion. RESULTS We showed that Tlr4-deficient mice display significantly reduced expression of proinflammatory genes, including RelA, tumor necrosis factor (Thf), interleukin 6 (Il6), chemokine (C-C motif) ligand 2 (Ccl2), chemokine (C-C motif) ligand 5 (Ccl5), chemokine (C-X-C motif) ligand 10 (Cxcl10), Cybb, nitric oxide synthase 2 (Nos2), and intercellular adhesion molecule 1 (Icam1) 24 h after reperfusion. The mice that lacked Tlr4 showed significantly increased survival of neurons in the ganglion cell layer following ischemic injury, as compared to wild-type controls. CONCLUSIONS Our results indicate that Tlr4 signaling is involved in retinal damage and inflammation triggered by ischemic injury.
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Affiliation(s)
- Galina Dvoriantchikova
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL
| | - David J. Barakat
- Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL
| | - Eleut Hernandez
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL
| | - Valery I. Shestopalov
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL,Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL
| | - Dmitry Ivanov
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL,Vavilov Institute of General Genetics RAS, Moscow, Russian Federation
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Karlstetter M, Ebert S, Langmann T. Microglia in the healthy and degenerating retina: insights from novel mouse models. Immunobiology 2010; 215:685-91. [PMID: 20573418 DOI: 10.1016/j.imbio.2010.05.010] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 05/20/2010] [Indexed: 12/24/2022]
Abstract
In contrast to the tremendous amount of research data from the central nervous system, relatively little is known about microglial homeostasis in the retina. This may be explained by a strong research bias towards important brain pathologies including Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis. In addition, there are specific technical limitations which hampered the analysis of retinal microglia, including their relatively small number in ocular tissue. The lack of experimental tools also prevented direct visualization and molecular analysis of this specialized neuronal macrophage population. Over the last few years, this situation has changed considerably as more and more retinal disorders have come into focus. Many rare monogenic forms as well as more prevalent complex disorders, in particular the age-related macular degeneration involves innate immune mechanisms. As a consequence, new genetic and experimental mouse models have been developed that mimic various forms of human retinal degeneration. In conjunction with these disease models, novel macrophage/microglia-specific reporter mice were established that allow the monitoring of retinal microglia in situ and in vivo. This review summarizes recent findings from these mouse models and thereby provides an overview of microglial homeostasis in the healthy and degenerating retina. Based on this knowledge, microglia-targeted therapies are envisioned which could delay or attenuate degenerative retinal disease.
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Affiliation(s)
- Marcus Karlstetter
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
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Zeiss CJ. Animals as models of age-related macular degeneration: an imperfect measure of the truth. Vet Pathol 2010; 47:396-413. [PMID: 20382825 DOI: 10.1177/0300985809359598] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Age-related macular degeneration (AMD) is a degenerative condition that begins in Bruch's membrane and progresses to involve the retinal pigment epithelium and ultimately the overlying photoreceptors. The only required etiologic factor is age, and AMD is regarded as the leading cause of blindness in individuals older than 65 years. AMD results from variable contributions of age, environment, and genetic predisposition. Many loci are linked to AMD; in the majority of cases, the disease is associated with polymorphisms within these genes, rather than mutations that ablate gene function. The etiologic complexity of AMD is reflected by the paucity of animal models that entirely replicate the human disease. This review compares the salient anatomy of the primate and rodent retina, particularly in the light of AMD pathology. It next discusses prevailing hypotheses explaining how AMD may develop. These include the role of complement activation and macrophage chemotaxis in AMD, molecular mechanisms of choroidal neovascularization, and the roles of oxidative damage and lipid metabolism. Finally, the article gives an overview of spontaneous and induced nonhuman primate models and describes relevant mouse models in the context of each pathogenetic mechanism.
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Affiliation(s)
- C J Zeiss
- Yale University School of Medicine, Section of Comparative Medicine, 375 Congress Avenue, New Haven, CT 06520, USA.
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Galzi JL, Hachet-Haas M, Bonnet D, Daubeuf F, Lecat S, Hibert M, Haiech J, Frossard N. Neutralizing endogenous chemokines with small molecules. Principles and potential therapeutic applications. Pharmacol Ther 2010; 126:39-55. [PMID: 20117133 PMCID: PMC7112609 DOI: 10.1016/j.pharmthera.2009.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 12/24/2009] [Indexed: 02/08/2023]
Abstract
Regulation of cellular responses to external stimuli such as hormones, neurotransmitters, or cytokines is achieved through the control of all steps of the complex cascade starting with synthesis, going through maturation steps, release, distribution, degradation and/or uptake of the signalling molecule interacting with the target protein. One possible way of regulation, referred to as scavenging or neutralization of the ligand, has been increasingly studied, especially for small protein ligands. It shows innovative potential in chemical biology approaches as well as in disease treatment. Neutralization of protein ligands, as for example cytokines or chemokines can lead to the validation of signalling pathways under physiological or pathophysiological conditions, and in certain cases, to the development of therapeutic molecules now used in autoimmune diseases, chronic inflammation and cancer treatment. This review explores the field of ligand neutralization and tries to determine to what extent small chemical molecules could substitute for neutralizing antibodies in therapeutic approaches.
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Affiliation(s)
- Jean-Luc Galzi
- IREBS, FRE3211, Ecole Supérieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67412 Illkirch, France.
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Cao X, Liu M, Tuo J, Shen D, Chan CC. The effects of quercetin in cultured human RPE cells under oxidative stress and in Ccl2/Cx3cr1 double deficient mice. Exp Eye Res 2010; 91:15-25. [PMID: 20361964 DOI: 10.1016/j.exer.2010.03.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 03/16/2010] [Accepted: 03/18/2010] [Indexed: 12/17/2022]
Abstract
Quercetin, a member of the flavonoid family, is one of the most prominent dietary antioxidants. This study investigates the mechanisms for the effects of quercetin on cultured human RPE cells and in Ccl2/Cx3cr1 double knock-out (DKO) mice, which spontaneously develop progressive retinal lesions mimicking age-related macular degeneration (AMD). In the in vitro experiment, cultured ARPE-19 cells were exposed to 1 mM H(2)O(2) with or without 50 muM quercetin for 2 h. Cellular viability, mitochondrial function, and apoptosis were assessed using crystal violet staining, MTT assay, and comet assay, respectively. Apoptotic molecular transcripts of BCL-2, BAX, FADD, CASPASE-3 and CASPASE-9 were measured by RQ-PCR. COX activity and nitric oxide (NO) level were determined in the supernatant of the culture medium. Quercetin treatment protected ARPE-19 cells from H(2)O(2)-induced oxidative injury, enhanced BCL-2 transcript levels, increased the BCL-2/BAX ratio, suppressed the transcription of pro-apoptotic factors such as BAX, FADD, CASPASE-3 and CASPASE-9, inhibited the transcription of inflammatory factors such as TNF-alpha, COX-2 and INOS, and decreased the levels of COX and NO in the culture medium. In the in vivo experiment, DKO and C57/B6 mice were treated with 25 mg/kg/day quercetin by intraperitoneal injection daily for two months. Funduscopy was performed monthly. After two months, serum was collected to measure NADP(+)/NADPH, COX, PGE-2, and NO levels. The eyes were harvested for histology and A2E measurement. Ocular transcripts of Bcl-2, Bax, Cox-2, Inos, Tnf-alpha, Fas, FasL and Caspase-3 were detected by RQ-PCR. Quercetin treatment did not reverse the progression of retinal lesions in DKO mice funduscopically or histologically. Although quercetin treatment could recover systemic anti-oxidative capacity, suppress the systemic expression of NO, COX and PGE-2, and decrease ocular A2E levels, it could not effectively suppress the transcripts of the ocular inflammatory factors Tnf-alpha, Cox-2 and Inos, or the pro-apoptotic factors Fas, FasL and Caspase-3 in DKO mice. Our data demonstrate that quercetin can protect human RPE cells from oxidative stress in vitro via inhibition of pro-inflammatory molecules and direct inhibition of the intrinsic apoptosis pathway. However, quercetin (25 mg/kg/day) does not improve the retinal AMD-like lesions in the Ccl2(-/-)/Cx3cr1(-/-) mice, likely due to its insufficient suppression of the inflammatory and apoptosis pathways in the eye.
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Affiliation(s)
- Xiaoguang Cao
- Immunopathology Section, Laboratory of Immunology; National Eye Institute, National Institutes of Health, Bethesda, MD 20892-1857, USA
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Dhingra N, Kelly S, Majid MA, Bailey CB, Dick AD. Inflammatory choroidal neovascular membrane in posterior uveitis-pathogenesis and treatment. Indian J Ophthalmol 2010; 58:3-10. [PMID: 20029141 PMCID: PMC2841372 DOI: 10.4103/0301-4738.58467] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Choroidal neovascular membrane (CNVM) formation is a well-documented sight-threatening complication of posterior segment intraocular inflammation (PSII). The aim of this article is to review the basic and clinical science literature on the pathogenesis of CNVM formation in PSII and to present results of a case series. We searched the literature using the mesh terms- inflammation, CNVM, age-related macular degeneration, immunosuppression, photodynamic therapy, steroids, vascular endothelial growth factors and posterior uveitis. Additionally, we evaluated the visual outcome of and clinical response to our standard treatment protocol involving a combination treatment for young patients with inflammatory CNVM. The development of CNVM in PSII is promulgated by infiltrating myeloid cells as well as choroidal and retinal myeloid cell activation, subsequent vascular endothelial growth factors, cytokine and chemokine production and complement activation acting in consort to mediate angiogenic responses. No clear standard of care currently exists for the treatment of inflammatory CNVM and various combinations have been tried. Using our combination treatment, visual acuity improved in four, stabilized in one and worsened in four patients. Though significant advances have occurred in the understanding of the pathogenesis and management of this condition, optimizing therapeutic regimens will require further well-constructed prospective cohort series.
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Affiliation(s)
- Narendra Dhingra
- Department of Academic Ophthalmology, Bristol Eye Hospital, Bristol, United Kingdom
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Ramkumar HL, Zhang J, Chan CC. Retinal ultrastructure of murine models of dry age-related macular degeneration (AMD). Prog Retin Eye Res 2010; 29:169-90. [PMID: 20206286 DOI: 10.1016/j.preteyeres.2010.02.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Age-related macular degeneration (AMD) is the most prevalent form of irreversible blindness worldwide in the elderly population. The pathology of dry AMD consists of macular degeneration of photoreceptors and the RPE, lipofuscin (A2E) accumulation, and drusen formation. Mice have been widely used for generating models that simulate human AMD features for investigating the pathogenesis, treatment and prevention of the disease. Although the mouse has no macula, focal atrophy of photoreceptors and RPE, lipofuscin accumulation, and increased A2E can develop in aged mouse eyes. However, drusen are rarely seen in mice because of their simpler Bruch's membrane and different process of lipofuscin extrusion compared with humans. Thus, analyzing basal deposits at the ultrastructural level and understanding the ultrastructural pathologic differences between various mouse AMD models are critical to comprehending the significance of research findings and response to possible therapeutic options for dry AMD. Based on the multifactorial pathogenesis of AMD, murine dry AMD models can be classified into three groups. First, genetically engineered mice that target genes related to juvenile macular dystrophies are the most common models, and they include abcr(-/-) (Stargardt disease), transgenic ELOVL4 (Stargardt-3 dominant inheritary disease), Efemp1(R345W/R345W) (Doyne honeycomb retinal dystrophy), and Timp3(S156C/S156C) (Sorsby fundus dystrophy) mice. Other murine models target genes relevant to AMD, including inflammatory genes such as Cfh(-/-), Ccl2(-/-), Ccr2(-/-), Cx3cr1(-/-), and Ccl2(-/-)/cx3cr1(-/-), oxidative stress associated genes such as Sod1(-/-) and Sod2 knockdown, metabolic pathway genes such as neprilysin(-/-) (amyloid beta), transgenic mcd/mcd (cathepsin D), Cp(-/-)/Heph(-/Y) (ferroxidase ceruloplasmin/hepaestin, iron metabolism), and transgenic ApoE4 on high fat and high cholesterol diet (lipid metabolism). Second, mice have also been immunologically manipulated by immunization with carboxyethylpyrrole (CEP), an oxidative fragment of DHA found in drusen, and found to present with dry AMD features. Third, natural mouse strains such as arrd2/arrd2 (Mdm gene mutation) and the senescence accelerated mice (SAM) spontaneously develop features of dry AMD like photoreceptor atrophy and thickening of Bruch's membrane. All the aforementioned models develop retinal lesions with various features that simulate dry AMD lesions: focal photoreceptor degeneration, abnormal RPE with increased lipofuscin, basal infolding, decreased melanosomes and degeneration. However, Bruch's membrane changes are less common. Most mice develop retinal lesions at an older age (6-24 months, depending on the models), while the Ccl2(-/-)/cx3cr1(-/-) mice develop lesions by 4-6 weeks. Although murine models present various degrees of retinal and/or RPE degeneration, classical drusen is extremely rare. Using electron microscopy, small drusenoid deposits are found between RPE and Bruch's membrane in a few models including Efemp1(R345W/R345W), Ccl2(-/-)/cx3cr1(-/-), neprilysin(-/-), transgenic mcd/mcd, and ApoE4 transgenic mice on a high fat diet. High A2E levels are measured in the retinas of abcr(-/-), transgenic ELOVL4, and Ccl2(-/-)/cx3cr1(-/-) mice. In summary, murine models provide useful tools for studying AMD pathogenesis and evaluating novel therapies for this disease. This review compares the major dry AMD murine models and discusses retinal pathology at the ultrastructural level.
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Affiliation(s)
- Hema L Ramkumar
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892-1857, USA
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Tuo J. Age-related macular degeneration: the protective effects of omega-3 fatty acids as anti-inflammatory agents. EXPERT REVIEW OF OPHTHALMOLOGY 2010. [DOI: 10.1586/eop.09.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Herzlich AA, Ding X, Shen D, Ross RJ, Tuo J, Chan CC. Peroxisome Proliferator-Activated Receptor Expression in Murine Models and Humans with Age-related Macular Degeneration. ACTA ACUST UNITED AC 2009; 2:141-148. [PMID: 21152244 DOI: 10.2174/1874196700902010141] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) play a role in oxidative stress and VEGF regulation, which are closely related to age-related macular degeneration (AMD). PPAR γ expression and its downstream molecules were examined in fat-1 mice (transgenic mice that convert n-6 to n-3 fatty acids), Ccl2(-/-)/Cx3cr1(-/-) mice (an AMD model), ARPE19 cells (a human retinal pigment epithelial cell line, RPE, a cell type with a critical role in AMD), and human eyes with and without AMD. PPAR α, β, and γ, VEGF and receptors were determined by immunohistochemistry in the mice models, humans, and ARPE19 cells. Transcripts of PPARs, VEGF, MMP-9 and HO-1 were determined by RQ-PCR. PPARs were constitutively expressed in normal neuroretina and RPE of humans and mice. PPAR γ expression was increased in fat-1 and Ccl2(-/-)/Cx3cr1(-/-) mice. VEGF was decreased in fat-1 mice but increased in Ccl2(-/-)/Cx3cr1(-/-) mice. VEGF receptors were stable. VEGF, MMP9 and HO-1 transcript levels were increased in ARPE19 cells under H(2)O(2) - induced oxidative stress. Human AMD retinas exhibited higher PPAR γ. The findings of increased expression of PPAR γ and its downstream proteins (VEGF, MMP9, and HO-1) in H(2)O(2)-treated ARPE19 cells, Ccl2(-/-)/Cx3cr1(-/-) mice, and human AMD eyes, but decreased VEGF in fat-1 mice, suggest that PPAR γ may play a role in AMD.
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Affiliation(s)
- Alexandra A Herzlich
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Tuo J, Ross RJ, Herzlich AA, Shen D, Ding X, Zhou M, Coon SL, Hussein N, Salem N, Chan CC. A high omega-3 fatty acid diet reduces retinal lesions in a murine model of macular degeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:799-807. [PMID: 19608872 DOI: 10.2353/ajpath.2009.090089] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Age-related macular degeneration (AMD) is one of the leading cause of blindness among the elderly; however, current therapy options are limited. Epidemiological studies have shown that a diet that is high in omega-3 polyunsaturated (n-3) fatty acids can slow disease progression in patients with advanced AMD. In this study, we evaluated the effect of such a diet on the retinas of Ccl2(-/-)/Cx3cr1(-/-) mice, a model that develops AMD-like retinal lesions that include focal deep retinal lesions, abnormal retinal pigment epithelium, photoreceptor degeneration, and A2E accumulation. Ccl2(-/-)/Cx3cr1(-/-) mice that ingested a high n-3 fatty acid diet showed a slower progression of retinal lesions compared with the low n-3 fatty acids group. Some mice that were given high levels of n-3 fatty acids had lesion reversion. We found a shunted arachidonic acid metabolism that resulted in decreased pro-inflammatory derivatives (prostaglandin E(2) and leukotriene B(4)) and an increased anti-inflammatory derivative (prostaglandin D(2)). We also measured lower ocular TNF-alpha and IL-6 transcript levels in the mice fed a diet of high n-3 fatty acids. Our findings in these mice are in line with human studies of AMD risk reduction by long-chain n-3 fatty acids. This murine model provides a useful tool to evaluate therapies that might delay the development of AMD.
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Affiliation(s)
- Jingsheng Tuo
- 10/10N103, NIH/NEI, 10 Center Dr., Bethesda, MD 20892-1857, USA
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