51
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Sánchez-Corral P, Pouw RB, López-Trascasa M, Józsi M. Self-Damage Caused by Dysregulation of the Complement Alternative Pathway: Relevance of the Factor H Protein Family. Front Immunol 2018; 9:1607. [PMID: 30050540 PMCID: PMC6052053 DOI: 10.3389/fimmu.2018.01607] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/28/2018] [Indexed: 12/13/2022] Open
Abstract
The alternative pathway is a continuously active surveillance arm of the complement system, and it can also enhance complement activation initiated by the classical and the lectin pathways. Various membrane-bound and plasma regulatory proteins control the activation of the potentially deleterious complement system. Among the regulators, the plasma glycoprotein factor H (FH) is the main inhibitor of the alternative pathway and its powerful amplification loop. FH belongs to a protein family that also includes FH-like protein 1 and five factor H-related (FHR-1 to FHR-5) proteins. Genetic variants and abnormal rearrangements involving the FH protein family have been linked to numerous systemic and organ-specific diseases, including age-related macular degeneration, and the renal pathologies atypical hemolytic uremic syndrome, C3 glomerulopathies, and IgA nephropathy. This review covers the known and recently emerged ligands and interactions of the human FH family proteins associated with disease and discuss the very recent experimental data that suggest FH-antagonistic and complement-activating functions for the FHR proteins.
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Affiliation(s)
- Pilar Sánchez-Corral
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Richard B Pouw
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Margarita López-Trascasa
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain.,Department of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Mihály Józsi
- Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary.,MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
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52
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Goicoechea de Jorge E, López Lera A, Bayarri-Olmos R, Yebenes H, Lopez-Trascasa M, Rodríguez de Córdoba S. Common and rare genetic variants of complement components in human disease. Mol Immunol 2018; 102:42-57. [PMID: 29914697 DOI: 10.1016/j.molimm.2018.06.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/06/2018] [Accepted: 06/08/2018] [Indexed: 12/21/2022]
Abstract
Genetic variability in the complement system and its association with disease has been known for more than 50 years, but only during the last decade have we begun to understand how this complement genetic variability contributes to the development of diseases. A number of reports have described important genotype-phenotype correlations that associate particular diseases with genetic variants altering specific aspects of the activation and regulation of the complement system. The detailed functional characterization of some of these genetic variants provided key insights into the pathogenic mechanisms underlying these pathologies, which is facilitating the design of specific anti-complement therapies. Importantly, these analyses have sometimes revealed unknown features of the complement proteins. As a whole, these advances have delineated the functional implications of genetic variability in the complement system, which supports the implementation of a precision medicine approach based on the complement genetic makeup of the patients. Here we provide an overview of rare complement variants and common polymorphisms associated with disease and discuss what we have learned from them.
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Affiliation(s)
- Elena Goicoechea de Jorge
- Department of Immunology, Complutense University, Madrid, Spain; Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Alberto López Lera
- Research Institute Hospital Universitario La Paz (IdiPaz), Madrid, Spain; Ciber de Enfermedades Raras, Madrid, Spain
| | - Rafael Bayarri-Olmos
- Department of Clinical Immunology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Hugo Yebenes
- Ciber de Enfermedades Raras, Madrid, Spain; Molecular Pathology and Complement Genetics Unit. Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | | | - Santiago Rodríguez de Córdoba
- Ciber de Enfermedades Raras, Madrid, Spain; Molecular Pathology and Complement Genetics Unit. Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
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53
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Yang Y, Denton H, Davies OR, Smith-Jackson K, Kerr H, Herbert AP, Barlow PN, Pickering MC, Marchbank KJ. An Engineered Complement Factor H Construct for Treatment of C3 Glomerulopathy. J Am Soc Nephrol 2018; 29:1649-1661. [PMID: 29588430 PMCID: PMC6054357 DOI: 10.1681/asn.2017091006] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 02/26/2018] [Indexed: 01/06/2023] Open
Abstract
Background C3 glomerulopathy (C3G) is associated with dysregulation of the alternative pathway of complement activation, and treatment options for C3G remain limited. Complement factor H (FH) is a potent regulator of the alternative pathway and might offer a solution, but the mass and complexity of FH makes generation of full-length FH far from trivial. We previously generated a mini-FH construct, with FH short consensus repeats 1-5 linked to repeats 18-20 (FH1-5^18-20), that was effective in experimental C3G. However, the serum t1/2 of FH1-5^18-20 was significantly shorter than that of serum-purified FH.Methods We introduced the oligomerization domain of human FH-related protein 1 (denoted by R1-2) at the carboxy or amino terminus of human FH1-5^18-20 to generate two homodimeric mini-FH constructs (FHR1-2^1-5^18-20 and FH1-5^18-20^R1-2, respectively) in Chinese hamster ovary cells and tested these constructs using binding, fluid-phase, and erythrocyte lysis assays, followed by experiments in FH-deficient Cfh-/- mice.Results FHR1-2^1-5^18-20 and FH1-5^18-20^R1-2 homodimerized in solution and displayed avid binding profiles on clustered C3b surfaces, particularly FHR1-2^1-5^18-20 Each construct was >10-fold more effective than FH at inhibiting cell surface complement activity in vitro and restricted glomerular basement membrane C3 deposition in vivo significantly better than FH or FH1-5^18-20 FH1-5^18-20^R1-2 had a C3 breakdown fragment binding profile similar to that of FH, a >5-fold increase in serum t1/2 compared with that of FH1-5^18-20, and significantly better retention in the kidney than FH or FH1-5^18-20Conclusions FH1-5^18-20^R1-2 may have utility as a treatment option for C3G or other complement-mediated diseases.
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Affiliation(s)
- Yi Yang
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Harriet Denton
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Owen R Davies
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Kate Smith-Jackson
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Heather Kerr
- Department of Chemistry, Edinburgh University, Edinburgh, UK; and
| | - Andrew P Herbert
- Department of Chemistry, Edinburgh University, Edinburgh, UK; and
| | - Paul N Barlow
- Department of Chemistry, Edinburgh University, Edinburgh, UK; and
| | | | - Kevin J Marchbank
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK;
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54
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Warwick A, Lotery A. Genetics and genetic testing for age-related macular degeneration. Eye (Lond) 2018; 32:849-857. [PMID: 29125146 PMCID: PMC5944647 DOI: 10.1038/eye.2017.245] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/09/2017] [Indexed: 12/21/2022] Open
Abstract
Considerable advances have been made in our understanding of age-related macular degeneration (AMD) genetics over the past decade. The genetic associations discovered to date are estimated to account for approximately half of AMD heritability, and functional studies of these variants have revealed new insights into disease pathogenesis, leading to the development of potential novel therapies. There is furthermore growing interest in genetic testing for predicting an individual's risk of AMD and offering personalised preventive or therapeutic treatments. We review the progress made so far in AMD genetics and discuss the possible applications for genetic testing.
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Affiliation(s)
| | - A Lotery
- Clinical Neurosciences Research Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.
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55
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Krilis M, Qi M, Madigan MC, Wong JWH, Abdelatti M, Guymer RH, Whitelock J, McCluskey P, Zhang P, Qi J, Hunyor AP, Krilis SA, Giannakopoulos B. Nitration of tyrosines in complement factor H domains alters its immunological activity and mediates a pathogenic role in age related macular degeneration. Oncotarget 2018; 8:49016-49032. [PMID: 28159936 PMCID: PMC5564745 DOI: 10.18632/oncotarget.14940] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 12/27/2016] [Indexed: 11/25/2022] Open
Abstract
Nitrosative stress has been implicated in the pathogenesis of age related macular degeneration (AMD). Tyrosine nitration is a unique type of post translational modification that occurs in the setting of inflammation and nitrosative stress. To date, the significance and functional implications of tyrosine nitration of complement factor H (CFH), a key complement regulator in the eye has not been explored, and is examined in this study in the context of AMD pathogenesis. Sections of eyes from deceased individuals with AMD (n = 5) demonstrated the presence of immunoreactive nitrotyrosine CFH. We purified nitrated CFH from retinae from 2 AMD patients. Mass spectrometry of CFH isolated from AMD eyes revealed nitrated residues in domains critical for binding to heparan sulphate glycosaminoglycans (GAGs), lipid peroxidation by-products and complement (C) 3b. Functional studies revealed that nitrated CFH did not bind to lipid peroxidation products, nor to the GAG of perlecan nor to C3b. There was loss of cofactor activity for Factor I mediated cleavage of C3b with nitrated CFH compared to non-nitrated CFH. CFH inhibits, but nitrated CFH significantly potentiates, the secretion of the pro-inflammatory and angiogenic cytokine IL-8 from monocytes that have been stimulated with lipid peroxidation by-products. AMD patients (n = 30) and controls (n = 30) were used to measure plasma nitrated CFH using a novel ELISA. AMD patients had significantly elevated nitrated CFH levels compared to controls (p = 0.0117). These findings strongly suggest that nitrated CFH contributes to AMD progression, and is a target for therapeutic intervention.
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Affiliation(s)
- Matthew Krilis
- Save Sight Institute, University of Sydney and Sydney Eye Hospital, Sydney, NSW, Australia
| | - Miao Qi
- Department of Infectious Diseases, Immunology and Sexual Health and Department of Medicine, St George Hospital, University of New South Wales, Sydney, NSW, Australia
| | - Michele C Madigan
- Save Sight Institute, University of Sydney and Sydney Eye Hospital, Sydney, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia
| | - Jason W H Wong
- Prince of Wales Clinical School, University of New South Wales, Lowy Cancer Research Centre, Sydney, NSW, Australia
| | - Mahmoud Abdelatti
- Department of Infectious Diseases, Immunology and Sexual Health and Department of Medicine, St George Hospital, University of New South Wales, Sydney, NSW, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - John Whitelock
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Peter McCluskey
- Save Sight Institute, University of Sydney and Sydney Eye Hospital, Sydney, NSW, Australia
| | - Peng Zhang
- Department of Infectious Diseases, Immunology and Sexual Health and Department of Medicine, St George Hospital, University of New South Wales, Sydney, NSW, Australia.,Department of Cardiothoracic Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Jian Qi
- Department of Infectious Diseases, Immunology and Sexual Health and Department of Medicine, St George Hospital, University of New South Wales, Sydney, NSW, Australia
| | - Alex P Hunyor
- Save Sight Institute, University of Sydney and Sydney Eye Hospital, Sydney, NSW, Australia
| | - Steven A Krilis
- Department of Infectious Diseases, Immunology and Sexual Health and Department of Medicine, St George Hospital, University of New South Wales, Sydney, NSW, Australia
| | - Bill Giannakopoulos
- Department of Infectious Diseases, Immunology and Sexual Health and Department of Medicine, St George Hospital, University of New South Wales, Sydney, NSW, Australia.,Department of Rheumatology, St George Hospital, Sydney, NSW, Australia
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56
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Molins B, Romero-Vázquez S, Fuentes-Prior P, Adan A, Dick AD. C-Reactive Protein as a Therapeutic Target in Age-Related Macular Degeneration. Front Immunol 2018; 9:808. [PMID: 29725335 PMCID: PMC5916960 DOI: 10.3389/fimmu.2018.00808] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/03/2018] [Indexed: 01/26/2023] Open
Abstract
Age-related macular degeneration (AMD), a retinal degenerative disease, is the leading cause of central vision loss among the elderly population in developed countries and an increasing global burden. The major risk is aging, compounded by other environmental factors and association with genetic variants for risk of progression. Although the etiology of AMD is not yet clearly understood, several pathogenic pathways have been proposed, including dysfunction of the retinal pigment epithelium, inflammation, and oxidative stress. The identification of AMD susceptibility genes encoding complement factors and the presence of complement and other inflammatory mediators in drusen, the hallmark deposits of AMD, support the concept that local inflammation and immune-mediated processes play a key role in AMD pathogenesis that may be accelerated through systemic immune activation. In this regard, increased levels of circulating C-reactive protein (CRP) have been associated with higher risk of AMD. Besides being a risk marker for AMD, CRP may also play a role in the progression of the disease as it has been identified in drusen, and we have recently found that its monomeric form (mCRP) induces blood retinal barrier disruption in vitro. In this review, we will address recent evidence that links CRP and AMD pathogenesis, which may open new therapeutic opportunities to prevent the progression of AMD.
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Affiliation(s)
- Blanca Molins
- Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, Barcelona, Spain
| | - Sara Romero-Vázquez
- Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, Barcelona, Spain
| | - Pablo Fuentes-Prior
- Molecular Bases of Disease, Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain.,Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Alfredo Adan
- Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, Barcelona, Spain
| | - Andrew D Dick
- Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.,Academic Unit of Ophthalmology, School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom.,National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital, University College London Institute of Ophthalmology, London, United Kingdom
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57
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Chirco KR, Potempa LA. C-Reactive Protein As a Mediator of Complement Activation and Inflammatory Signaling in Age-Related Macular Degeneration. Front Immunol 2018; 9:539. [PMID: 29599782 PMCID: PMC5862805 DOI: 10.3389/fimmu.2018.00539] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/02/2018] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is a devastating neurodegenerative disease affecting millions worldwide. Complement activation, inflammation, and the loss of choroidal endothelial cells have been established as key factors in both normal aging and AMD; however, the exact mechanisms for these events have yet to be fully uncovered. Herein, we provide evidence that the prototypic acute phase reactant, C-reactive protein (CRP), contributes to AMD pathogenesis. We discuss serum CRP levels as a risk factor for disease, immunolocalization of distinct forms of CRP in the at-risk and diseased retina, and direct effects of CRP on ocular tissue. Furthermore, we discuss the complement system as it relates to AMD pathophysiology, provide a model for the role of CRP in this disease, and outline current therapies being developed and tested to treat AMD patients.
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58
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C-reactive protein and pentraxin-3 binding of factor H-like protein 1 differs from complement factor H: implications for retinal inflammation. Sci Rep 2018; 8:1643. [PMID: 29374201 PMCID: PMC5786067 DOI: 10.1038/s41598-017-18395-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 12/11/2017] [Indexed: 12/31/2022] Open
Abstract
Retinal inflammation plays a key role in the progression of age-related macular degeneration (AMD), a condition that leads to loss of central vision. The deposition of the acute phase pentraxin C-reactive protein (CRP) in the macula activates the complement system, thereby contributing to dysregulated inflammation. The complement protein factor H (FH) can bind CRP and down-regulate an inflammatory response. However, it is not known whether a truncated form of FH, called factor H-like protein 1 (FHL-1), which plays a significant regulatory role in the eye, also interacts with CRP. Here, we compare the binding properties of FHL-1 and FH to both CRP and the related protein pentraxin-3 (PTX3). We find that, unlike FH, FHL-1 can bind pro-inflammatory monomeric CRP (mCRP) as well as the circulating pentameric form. Furthermore, the four-amino acid C-terminal tail of FHL-1 (not present in FH) plays a role in mediating its binding to mCRP. PTX3 was found to be present in the macula of donor eyes and the AMD-associated Y402H polymorphism altered the binding of FHL-1 to PTX3. Our findings reveal that the binding characteristics of FHL-1 differ from those of FH, likely underpinning independent immune regulatory functions in the context of the human retina.
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59
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Clark SJ, McHarg S, Tilakaratna V, Brace N, Bishop PN. Bruch's Membrane Compartmentalizes Complement Regulation in the Eye with Implications for Therapeutic Design in Age-Related Macular Degeneration. Front Immunol 2017; 8:1778. [PMID: 29312308 PMCID: PMC5742201 DOI: 10.3389/fimmu.2017.01778] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/28/2017] [Indexed: 11/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the western world and affects nearly 200 million people globally. Local inflammation driven by complement system dysregulation is currently a therapeutic target. Bruch’s membrane (BrM) is a sheet of extracellular matrix that separates the retina from the underlying choroid, a highly vascularized layer that supplies oxygen and nutrition to the outer retina. Here, we show that most complement proteins are unable to diffuse through BrM, although FHL-1, factor D and C5a can. AMD-associated lipid deposition in BrM decreases FHL-1 diffusion. We show that this impermeability of BrM creates two separate semi-independent compartments with respect to complement activation and regulation. Complement proteins synthesized locally on either side of BrM, or on the choroidal side if derived from the circulation, predominantly remain on their side of origin. As previous studies suggest that complement activation in AMD is confined to the choroidal side of BrM, we propose a model whereby complement activation in the choriocapillaris layer of the choroid generates C5a, which crosses BrM to interact with its specific receptor on RPE cells to initiate an inflammatory response in the retina. Understanding mechanisms underpinning AMD is essential for developing therapeutics that target the right molecule in the right anatomical compartment.
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Affiliation(s)
- Simon J Clark
- Division of Evolution and Genomic Medicine, Faculty of Biology Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Selina McHarg
- Division of Evolution and Genomic Medicine, Faculty of Biology Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Viranga Tilakaratna
- Division of Evolution and Genomic Medicine, Faculty of Biology Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Nicole Brace
- Division of Evolution and Genomic Medicine, Faculty of Biology Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Paul N Bishop
- Division of Evolution and Genomic Medicine, Faculty of Biology Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, United Kingdom.,Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
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60
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Mullins RF, Warwick AN, Sohn EH, Lotery AJ. From compliment to insult: genetics of the complement system in physiology and disease in the human retina. Hum Mol Genet 2017; 26:R51-R57. [PMID: 28482029 DOI: 10.1093/hmg/ddx181] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/05/2017] [Indexed: 01/11/2023] Open
Abstract
Age-related macular degeneration (AMD) is a major cause of visual impairment that affects the central retina. Genome wide association studies and candidate gene screens have identified members of the complement pathway as contributing to the risk of AMD. In this review, we discuss the complement system, its importance in retinal development and normal physiology, how its dysregulation may contribute to disease, and how it might be targeted to prevent damage to the aging choriocapillaris in AMD.
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Affiliation(s)
- Robert F Mullins
- Department of Ophthalmology and Visual Sciences.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Alasdair N Warwick
- Western Eye Hospital, Imperial College Healthcare NHS Foundation Trust, London, UK
| | - Elliott H Sohn
- Department of Ophthalmology and Visual Sciences.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
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61
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Schnabolk G, Parsons N, Obert E, Annamalai B, Nasarre C, Tomlinson S, Lewin AS, Rohrer B. Delivery of CR2-fH Using AAV Vector Therapy as Treatment Strategy in the Mouse Model of Choroidal Neovascularization. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 9:1-11. [PMID: 29234687 PMCID: PMC5723362 DOI: 10.1016/j.omtm.2017.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/06/2017] [Indexed: 12/12/2022]
Abstract
Complement activation plays a significant role in age-related macular degeneration (AMD) pathogenesis, and polymorphisms interfering with factor H (fH) function, a complement alternative pathway (AP) inhibitor, are associated with increased AMD risk. We have previously validated an AP inhibitor, a fusion protein consisting of a complement receptor 2 fragment linked to the inhibitory domain of fH (CR2-fH) as an efficacious treatment for choroidal neovascularization (CNV) when delivered intravenously. Here we tested an alternative approach of AAV-mediated delivery (AAV5-VMD2-CR2-fH or AAV5-VMD2-mCherry) using subretinal delivery in C57BL/6J mice. Secretion of CR2-fH was confirmed in polarized retinal pigment epithelium (RPE) cells. A safe concentration of AAV5-VMD2-CR2-fH was identified using electroretinography, optical coherence tomography (OCT), RPE morphology, and antibody profiling. One month after gene delivery, CNV was induced using argon laser photocoagulation. OCT assessment demonstrated reduced CNV with AAV5-VMD2-CR2-fH administration. Bioavailability studies revealed that gene-therapy delivered similar levels of CR2-fH to the RPE/choroid as treatment by intravenous injections, and C3a ELISA verified reduced CNV-associated ocular C3a production. These results contribute to existing data illustrating the importance of the AP of complement in CNV development and its potential role in AMD treatment. Demonstration of AAV-vector efficacy opens new avenues for the development of treatment strategies.
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Affiliation(s)
- Gloriane Schnabolk
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Nathaniel Parsons
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Elisabeth Obert
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | | | - Cecile Nasarre
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA.,Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville FL 32611, USA
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA.,Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
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62
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On phagocytes and macular degeneration. Prog Retin Eye Res 2017; 61:98-128. [DOI: 10.1016/j.preteyeres.2017.06.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/29/2017] [Accepted: 06/05/2017] [Indexed: 12/17/2022]
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63
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Hallam D, Collin J, Bojic S, Chichagova V, Buskin A, Xu Y, Lafage L, Otten EG, Anyfantis G, Mellough C, Przyborski S, Alharthi S, Korolchuk V, Lotery A, Saretzki G, McKibbin M, Armstrong L, Steel D, Kavanagh D, Lako M. An Induced Pluripotent Stem Cell Patient Specific Model of Complement Factor H (Y402H) Polymorphism Displays Characteristic Features of Age-Related Macular Degeneration and Indicates a Beneficial Role for UV Light Exposure. Stem Cells 2017; 35:2305-2320. [PMID: 28913923 PMCID: PMC5698780 DOI: 10.1002/stem.2708] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 08/21/2017] [Accepted: 09/07/2017] [Indexed: 11/11/2022]
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness, accounting for 8.7% of all blindness globally. Vision loss is caused ultimately by apoptosis of the retinal pigment epithelium (RPE) and overlying photoreceptors. Treatments are evolving for the wet form of the disease; however, these do not exist for the dry form. Complement factor H polymorphism in exon 9 (Y402H) has shown a strong association with susceptibility to AMD resulting in complement activation, recruitment of phagocytes, RPE damage, and visual decline. We have derived and characterized induced pluripotent stem cell (iPSC) lines from two subjects without AMD and low-risk genotype and two patients with advanced AMD and high-risk genotype and generated RPE cells that show local secretion of several proteins involved in the complement pathway including factor H, factor I, and factor H-like protein 1. The iPSC RPE cells derived from high-risk patients mimic several key features of AMD including increased inflammation and cellular stress, accumulation of lipid droplets, impaired autophagy, and deposition of "drüsen"-like deposits. The low- and high-risk RPE cells respond differently to intermittent exposure to UV light, which leads to an improvement in cellular and functional phenotype only in the high-risk AMD-RPE cells. Taken together, our data indicate that the patient specific iPSC model provides a robust platform for understanding the role of complement activation in AMD, evaluating new therapies based on complement modulation and drug testing. Stem Cells 2017;35:2305-2320.
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Affiliation(s)
- Dean Hallam
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Joseph Collin
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Sanja Bojic
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Valeria Chichagova
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Adriana Buskin
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Yaobo Xu
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Lucia Lafage
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Elsje G Otten
- Campus for Ageing and Vitality, Institute for Cell and Molecular Biosciences and Institute for Ageing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - George Anyfantis
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Carla Mellough
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Stefan Przyborski
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Sameer Alharthi
- Princess Al Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Saudi Arabia
| | - Viktor Korolchuk
- Campus for Ageing and Vitality, Institute for Cell and Molecular Biosciences and Institute for Ageing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Gabriele Saretzki
- Campus for Ageing and Vitality, Institute for Cell and Molecular Biosciences and Institute for Ageing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Lyle Armstrong
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - David Steel
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - David Kavanagh
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
| | - Majlinda Lako
- Institute of Genetic Medicine, International Centre for Life, United Kingdom
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64
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Clark SJ, Bishop PN. The eye as a complement dysregulation hotspot. Semin Immunopathol 2017; 40:65-74. [PMID: 28948331 PMCID: PMC5794836 DOI: 10.1007/s00281-017-0649-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 08/30/2017] [Indexed: 01/23/2023]
Abstract
Complement turnover is tightly regulated throughout the human body in order to prevent over-activation and subsequent damage from inflammation. In the eye, low-level complement activation is maintained to provide immune tolerance in this immune privileged organ. Conversely, the complement system is suppressed in the cornea to protect it from continuous immunological insult. Over-activation of the complement cascade has been implicated in the disease progression of glaucoma and diabetic retinopathy and is now known to be a central driver in the pathogenesis of age-related macular degeneration (AMD). Indeed, it is with AMD where the most recent and exciting work has been carried out with complement-based therapies entering into clinical trials. However, the success of these trials will depend upon delivering the therapeutics to the correct anatomical sites within the eye, so a full understanding of how complement regulation is compartmentalized in the eye is required, a topic that will be highlighted in this review.
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Affiliation(s)
- Simon J Clark
- Division of Evolution and Genomic Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
| | - Paul N Bishop
- Division of Evolution and Genomic Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.,Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
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65
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Complement factor H in AMD: Bridging genetic associations and pathobiology. Prog Retin Eye Res 2017; 62:38-57. [PMID: 28928087 DOI: 10.1016/j.preteyeres.2017.09.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 09/08/2017] [Accepted: 09/13/2017] [Indexed: 01/28/2023]
Abstract
Age-Related Macular Degeneration (AMD) is a complex multifactorial disease characterized in its early stages by lipoprotein accumulations in Bruch's Membrane (BrM), seen on fundoscopic exam as drusen, and in its late forms by neovascularization ("wet") or geographic atrophy of the Retinal Pigmented Epithelial (RPE) cell layer ("dry"). Genetic studies have strongly supported a relationship between the alternative complement cascade, in particular the common H402 variant in Complement Factor H (CFH) and development of AMD. However, the functional significance of the CFH Y402H polymorphism remains elusive. In this article, we critically review the literature surrounding the functional significance of this polymorphism. Furthermore, based on our group's studies we propose a model in which CFH H402 affects CFH binding to heparan sulfate proteoglycans leading to accelerated lipoprotein accumulation in BrM and drusen progression. We also review the literature on the role of other complement components in AMD pathobiologies, including C3a, C5a and the membrane attack complex (MAC), and on transgenic mouse models developed to interrogate in vivo the effects of the CFH Y402H polymorphism.
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66
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Schmidt CQ, Lambris JD, Ricklin D. Protection of host cells by complement regulators. Immunol Rev 2017; 274:152-171. [PMID: 27782321 DOI: 10.1111/imr.12475] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The complement cascade is an ancient immune-surveillance system that not only provides protection from pathogen invasion but has also evolved to participate in physiological processes to maintain tissue homeostasis. The alternative pathway (AP) of complement activation is the evolutionarily oldest part of this innate immune cascade. It is unique in that it is continuously activated at a low level and arbitrarily probes foreign, modified-self, and also unaltered self-structures. This indiscriminate activation necessitates the presence of preformed regulators on autologous surfaces to spare self-cells from the undirected nature of AP activation. Although the other two canonical complement activation routes, the classical and lectin pathways, initiate the cascade more specifically through pattern recognition, their activity still needs to be tightly controlled to avoid excessive reactivity. It is the perpetual duty of complement regulators to protect the self from damage inflicted by inadequate complement activation. Here, we review the role of complement regulators as preformed mediators of defense, explain their common and specialized functions, and discuss selected cases in which alterations in complement regulators lead to disease. Finally, rational engineering approaches using natural complement inhibitors as potential therapeutics are highlighted.
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Affiliation(s)
- Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany.
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
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67
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Abstract
The complement system is a vital component of the immune-priveliged human eye that is always active at a low-grade level, preventing harmful intraocular injuries caused by accumulation of turnover products and controlling pathogens to preserve eye homeostasis and vision. The complement system is a double-edged sword that is essential for protection but may also become harmful and contribute to eye pathology. Here, we review the evidence for the involvement of complement system dysregulation in age-related macular degeneration, glaucoma, uveitis, and neuromyelitis optica, highlighting the relationship between morphogical changes and complement system protein expression and regulation in these diseases. The potential benefits of complement inhibition in age-related macular degeneration, glaucoma, uveitis, and neuromyelitis optica are abundant, as are those of further research to improve our understanding of complement-mediated injury in these diseases.
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Affiliation(s)
- Camilla Mohlin
- Linnæus Center of Biomaterials Chemistry, Linnæus University, Kalmar, Sweden
| | - Kerstin Sandholm
- Linnæus Center of Biomaterials Chemistry, Linnæus University, Kalmar, Sweden
| | - Kristina N Ekdahl
- Linnæus Center of Biomaterials Chemistry, Linnæus University, Kalmar, Sweden; Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Bo Nilsson
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
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68
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The impact of oxidative stress and inflammation on RPE degeneration in non-neovascular AMD. Prog Retin Eye Res 2017; 60:201-218. [PMID: 28336424 DOI: 10.1016/j.preteyeres.2017.03.002] [Citation(s) in RCA: 487] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 02/07/2023]
Abstract
The retinal pigment epithelium (RPE) is a highly specialized, unique epithelial cell that interacts with photoreceptors on its apical side and with Bruch's membrane and the choriocapillaris on its basal side. Due to vital functions that keep photoreceptors healthy, the RPE is essential for maintaining vision. With aging and the accumulated effects of environmental stresses, the RPE can become dysfunctional and die. This degeneration plays a central role in age-related macular degeneration (AMD) pathobiology, the leading cause of blindness among the elderly in western societies. Oxidative stress and inflammation have both physiological and potentially pathological roles in RPE degeneration. Given the central role of the RPE, this review will focus on the impact of oxidative stress and inflammation on the RPE with AMD pathobiology. Physiological sources of oxidative stress as well as unique sources from photo-oxidative stress, the phagocytosis of photoreceptor outer segments, and modifiable factors such as cigarette smoking and high fat diet ingestion that can convert oxidative stress into a pathological role, and the negative impact of impairing the cytoprotective roles of mitochondrial dynamics and the Nrf2 signaling system on RPE health in AMD will be discussed. Likewise, the response by the innate immune system to an inciting trigger, and the potential role of local RPE production of inflammation, as well as a potential role for damage by inflammation with chronicity if the inciting trigger is not neutralized, will be debated.
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69
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Zhang P, Zhu M, Geng-Spyropoulos M, Shardell M, Gonzalez-Freire M, Gudnason V, Eiriksdottir G, Schaumberg D, Van Eyk JE, Ferrucci L, Semba RD. A novel, multiplexed targeted mass spectrometry assay for quantification of complement factor H (CFH) variants and CFH-related proteins 1-5 in human plasma. Proteomics 2017; 17:10.1002/pmic.201600237. [PMID: 27647805 PMCID: PMC5534329 DOI: 10.1002/pmic.201600237] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/27/2016] [Accepted: 09/14/2016] [Indexed: 11/08/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of visual loss among older adults. Two variants in the complement factor H (CFH) gene, Y402H and I62V, are strongly associated with risk of AMD. CFH is encoded in regulator of complement activation gene cluster in chromosome 1q32, which includes complement factor related (CFHR) proteins, CFHR1 to CFHR5, with high amino acid sequence homology to CFH. Our goal was to build a SRM assay to measure plasma concentrations of CFH variants Y402, H402, I62, and V62, and CFHR1-5. The final assay consisted of 24 peptides and 72 interference-free SRM transition ion pairs. Most peptides showed good linearity over 0.3-200 fmol/μL concentration range. Plasma concentrations of CFH variants and CFHR1-5 were measured using the SRM assay in 344 adults. Plasma CFH concentrations (mean, SE in μg/mL) by inferred genotype were: YY402, II62 (170.1, 31.4), YY402, VV62 (188.8, 38.5), HH402, VV62 (144.0, 37.0), HY402, VV62 (164.2, 42.3), YY402, IV62 (194.8, 36.8), HY402, IV62 (181.3, 44.7). Mean (SE) plasma concentrations of CFHR1-5 were 1.63 (0.04), 3.64 (1.20), 0.020 (0.001), 2.42 (0.18), and 5.49 (1.55) μg/mL, respectively. This SRM assay should facilitate the study of the role of systemic complement and risk of AMD.
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Affiliation(s)
- Pingbo Zhang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Min Zhu
- National Institute on Aging, National Institutes of Health, Baltimore, MD
| | | | - Michelle Shardell
- National Institute on Aging, National Institutes of Health, Baltimore, MD
| | | | - Vilmundur Gudnason
- Icelandic Heart Association, Reykjavik, Iceland
- Department of Medicine, University of Iceland, Reykjavik, Iceland
| | | | - Debra Schaumberg
- Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, MA
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT
| | - Jennifer E. Van Eyk
- Advanced Clinical BioSystems Research Institute, The Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Luigi Ferrucci
- National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Richard D. Semba
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
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70
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Calippe B, Augustin S, Beguier F, Charles-Messance H, Poupel L, Conart JB, Hu SJ, Lavalette S, Fauvet A, Rayes J, Levy O, Raoul W, Fitting C, Denèfle T, Pickering MC, Harris C, Jorieux S, Sullivan PM, Sahel JA, Karoyan P, Sapieha P, Guillonneau X, Gautier EL, Sennlaub F. Complement Factor H Inhibits CD47-Mediated Resolution of Inflammation. Immunity 2017; 46:261-272. [DOI: 10.1016/j.immuni.2017.01.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 11/20/2016] [Accepted: 12/12/2016] [Indexed: 12/16/2022]
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71
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Liszewski MK, Java A, Schramm EC, Atkinson JP. Complement Dysregulation and Disease: Insights from Contemporary Genetics. ANNUAL REVIEW OF PATHOLOGY 2017; 12:25-52. [PMID: 27959629 PMCID: PMC6020056 DOI: 10.1146/annurev-pathol-012615-044145] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The vertebrate complement system consists of sequentially interacting proteins that provide for a rapid and powerful host defense. Nearly 60 proteins comprise three activation pathways (classical, alternative, and lectin) and a terminal cytolytic pathway common to all. Attesting to its potency, nearly half of the system's components are engaged in its regulation. An emerging theme over the past decade is that variations in these inhibitors predispose to two scourges of modern humans. One, occurring most often in childhood, is a rare but deadly thrombomicroangiopathy called atypical hemolytic uremic syndrome. The other, age-related macular degeneration, is the most common form of blindness in the elderly. Their seemingly unrelated clinical presentations and pathologies share the common theme of overactivity of the complement system's alternative pathway. This review summarizes insights gained from contemporary genetics for understanding how dysregulation of this powerful innate immune system leads to these human diseases.
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Affiliation(s)
- M Kathryn Liszewski
- Division of Rheumatology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110;
| | - Anuja Java
- Division of Nephrology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | | | - John P Atkinson
- Division of Rheumatology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110;
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72
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Keir LS, Firth R, Aponik L, Feitelberg D, Sakimoto S, Aguilar E, Welsh GI, Richards A, Usui Y, Satchell SC, Kuzmuk V, Coward RJ, Goult J, Bull KR, Sharma R, Bharti K, Westenskow PD, Michael IP, Saleem MA, Friedlander M. VEGF regulates local inhibitory complement proteins in the eye and kidney. J Clin Invest 2017; 127:199-214. [PMID: 27918307 PMCID: PMC5199702 DOI: 10.1172/jci86418] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 10/28/2016] [Indexed: 12/15/2022] Open
Abstract
Outer retinal and renal glomerular functions rely on specialized vasculature maintained by VEGF that is produced by neighboring epithelial cells, the retinal pigment epithelium (RPE) and podocytes, respectively. Dysregulation of RPE- and podocyte-derived VEGF is associated with neovascularization in wet age-related macular degeneration (ARMD), choriocapillaris degeneration, and glomerular thrombotic microangiopathy (TMA). Since complement activation and genetic variants in inhibitory complement factor H (CFH) are also features of both ARMD and TMA, we hypothesized that VEGF and CFH interact. Here, we demonstrated that VEGF inhibition decreases local CFH and other complement regulators in the eye and kidney through reduced VEGFR2/PKC-α/CREB signaling. Patient podocytes and RPE cells carrying disease-associated CFH genetic variants had more alternative complement pathway deposits than controls. These deposits were increased by VEGF antagonism, a common wet ARMD treatment, suggesting that VEGF inhibition could reduce cellular complement regulatory capacity. VEGF antagonism also increased markers of endothelial cell activation, which was partially reduced by genetic complement inhibition. Together, these results suggest that VEGF protects the retinal and glomerular microvasculature, not only through VEGFR2-mediated vasculotrophism, but also through modulation of local complement proteins that could protect against complement-mediated damage. Though further study is warranted, these findings could be relevant for patients receiving VEGF antagonists.
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Affiliation(s)
- Lindsay S. Keir
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Rachel Firth
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Lyndsey Aponik
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Daniel Feitelberg
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Susumu Sakimoto
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Edith Aguilar
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Gavin I. Welsh
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Anna Richards
- Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Yoshihiko Usui
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- Tokyo Medical University Hospital, Tokyo, Japan
| | - Simon C. Satchell
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Valeryia Kuzmuk
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Richard J. Coward
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Jonathan Goult
- Centre for Cellular and Molecular Physiology, University of Oxford, United Kingdom
| | - Katherine R. Bull
- Centre for Cellular and Molecular Physiology, University of Oxford, United Kingdom
| | - Ruchi Sharma
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Kapil Bharti
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Peter D. Westenskow
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- The Lowy Medical Research Institute, La Jolla, California, USA
| | | | - Moin A. Saleem
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Martin Friedlander
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
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73
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Ocular neovascular-related diseases: immunological mechanisms of development and the potential of anti-angiogenic therapy. OPHTHALMOLOGY JOURNAL 2016. [DOI: 10.17816/ov9458-67] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The paper adresses three ocular diseases - “wet” type of age-related macular degeneration, diabetic macular edema and neovascular glaucoma, which have similar neovascular changes and immunological disorders. The key moment of neovascularization development is an imbalance between pro- and anti-angiogenic factors. Particular attention is paid to vascular endothelial growth factor (VEGF-A), pigment epithelial derived factor (PEDF), transforming growth factor-beta (ТGF-β). The paper discusses the “immune privilege” of the eye, ACAID phenomenon, aspects of choroidal neovascularization pathogenesis, inflammation as an important part of neovascularization and the protective response to endogenous and exogenous damage, as well as complement system’s disorders, cytokine status impairment and autoimmune mechanisms. Laser treatment is widely used for treatment of neovascular diseases, but pharmacotherapy is very important too. Anti-angiogenic therapy is extremely promising and is held to provide regression of the newly-formed vasculature and/or normalization of newly formed blood vessels structure and suppress the functional activity of a key proangiogenic factor VEGF-A. Pegaptanib, ranibizumab and bevacizumab are discussed, and results of international clinical trials MARINA, ANCHOR, FOCUS, PrONTO, IVAN, CATT, RESTORE are provided.
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74
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Parente R, Clark SJ, Inforzato A, Day AJ. Complement factor H in host defense and immune evasion. Cell Mol Life Sci 2016; 74:1605-1624. [PMID: 27942748 PMCID: PMC5378756 DOI: 10.1007/s00018-016-2418-4] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 12/30/2022]
Abstract
Complement is the major humoral component of the innate immune system. It recognizes pathogen- and damage-associated molecular patterns, and initiates the immune response in coordination with innate and adaptive immunity. When activated, the complement system unleashes powerful cytotoxic and inflammatory mechanisms, and thus its tight control is crucial to prevent damage to host tissues and allow restoration of immune homeostasis. Factor H is the major soluble inhibitor of complement, where its binding to self markers (i.e., particular glycan structures) prevents complement activation and amplification on host surfaces. Not surprisingly, mutations and polymorphisms that affect recognition of self by factor H are associated with diseases of complement dysregulation, such as age-related macular degeneration and atypical haemolytic uremic syndrome. In addition, pathogens (i.e., non-self) and cancer cells (i.e., altered-self) can hijack factor H to evade the immune response. Here we review recent (and not so recent) literature on the structure and function of factor H, including the emerging roles of this protein in the pathophysiology of infectious diseases and cancer.
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Affiliation(s)
- Raffaella Parente
- Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano, 20089, Milan, Italy
| | - Simon J Clark
- Division of Evolution and Genomic Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Antonio Inforzato
- Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano, 20089, Milan, Italy. .,Department of Medical Biotechnologies and Translational Medicine, University of Milan, Via Vanvitelli 32, 20129, Milan, Italy.
| | - Anthony J Day
- Wellcome Trust Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
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75
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Schäfer N, Grosche A, Reinders J, Hauck SM, Pouw RB, Kuijpers TW, Wouters D, Ehrenstein B, Enzmann V, Zipfel PF, Skerka C, Pauly D. Complement Regulator FHR-3 Is Elevated either Locally or Systemically in a Selection of Autoimmune Diseases. Front Immunol 2016; 7:542. [PMID: 27965669 PMCID: PMC5124756 DOI: 10.3389/fimmu.2016.00542] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/16/2016] [Indexed: 12/30/2022] Open
Abstract
The human complement factor H-related protein-3 (FHR-3) is a soluble regulator of the complement system. Homozygous cfhr3/1 deletion is a genetic risk factor for the autoimmune form of atypical hemolytic-uremic syndrome (aHUS), while also found to be protective in age-related macular degeneration (AMD). The precise function of FHR-3 remains to be fully characterized. We generated four mouse monoclonal antibodies (mAbs) for FHR-3 (RETC) without cross-reactivity to the complement factor H (FH)-family. These antibodies detected FHR-3 from human serum with a mean concentration of 1 μg/mL. FHR-3 levels in patients were significantly increased in sera from systemic lupus erythematosus, rheumatoid arthritis, and polymyalgia rheumatica but remained almost unchanged in samples from AMD or aHUS patients. Moreover, by immunostaining of an aged human donor retina, we discovered a local FHR-3 production by microglia/macrophages. The mAb RETC-2 modulated FHR-3 binding to C3b but not the binding of FHR-3 to heparin. Interestingly, FHR-3 competed with FH for binding C3b and the mAb RETC-2 reduced the interaction of FHR-3 and C3b, resulting in increased FH binding. Our results unveil a previously unknown systemic involvement of FHR-3 in rheumatoid diseases and a putative local role of FHR-3 mediated by microglia/macrophages in the damaged retina. We conclude that the local FHR-3/FH equilibrium in AMD is a potential therapeutic target, which can be modulated by our specific mAb RETC-2.
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Affiliation(s)
- Nicole Schäfer
- Department of Ophthalmology, University Hospital Regensburg , Regensburg , Germany
| | - Antje Grosche
- Institute of Human Genetics, University of Regensburg , Regensburg , Germany
| | - Joerg Reinders
- Institute of Functional Genomics, University of Regensburg , Regensburg , Germany
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Neuherberg , Germany
| | - Richard B Pouw
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Center, University of Amsterdam , Amsterdam , Netherlands
| | - Taco W Kuijpers
- Department of Pediatric Hematology, Immunology and Infectious Diseases, Academic Medical Center, Emma Children's Hospital, Amsterdam, Netherlands; Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory of the Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Diana Wouters
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Center, University of Amsterdam , Amsterdam , Netherlands
| | - Boris Ehrenstein
- Klinik und Poliklinik für Rheumatologie und Klinische Immunologie, Asklepios Klinikum Bad Abbach , Bad Abbach , Germany
| | - Volker Enzmann
- Department of Ophthalmology, Inselspital, University of Bern , Bern , Switzerland
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany; Friedrich Schiller University, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology , Jena , Germany
| | - Diana Pauly
- Department of Ophthalmology, University Hospital Regensburg , Regensburg , Germany
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76
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Hakobyan S, Harding K, Aiyaz M, Hye A, Dobson R, Baird A, Liu B, Harris CL, Lovestone S, Morgan BP. Complement Biomarkers as Predictors of Disease Progression in Alzheimer's Disease. J Alzheimers Dis 2016; 54:707-16. [PMID: 27567854 DOI: 10.3233/jad-160420] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
There is a critical unmet need for reliable markers of disease and disease course in mild cognitive impairment (MCI) and early Alzheimer's disease (AD). The growing appreciation of the importance of inflammation in early AD has focused attention on inflammatory biomarkers in cerebrospinal fluid or plasma; however, non-specific inflammation markers have disappointed to date. We have adopted a targeted approach, centered on an inflammatory pathway already implicated in the disease. Complement, a core system in innate immune defense and potent driver of inflammation, has been implicated in pathogenesis of AD based on a confluence of genetic, histochemical, and model data. Numerous studies have suggested that measurement of individual complement proteins or activation products in cerebrospinal fluid or plasma is useful in diagnosis, prediction, or stratification, but few have been replicated. Here we apply a novel multiplex assay to measure five complement proteins and four activation products in plasma from donors with MCI, AD, and controls. Only one complement analyte, clusterin, differed significantly between control and AD plasma (controls, 295 mg/l; AD, 388 mg/l: p < 10- 5). A model combining clusterin with relevant co-variables was highly predictive of disease. Three analytes (clusterin, factor I, terminal complement complex) were significantly different between MCI individuals who had converted to dementia one year later compared to non-converters; a model combining these three analytes with informative co-variables was highly predictive of conversion. The data confirm the relevance of complement biomarkers in MCI and AD and build the case for using multi-parameter models for disease prediction and stratification.
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Affiliation(s)
| | - Katharine Harding
- Division of Neurosciences and Mental Health, Cardiff University, Cardiff, UK
| | - Mohammed Aiyaz
- King's College London, Institute of Psychology, Psychiatry and Neuroscience, London, UK
| | - Abdul Hye
- King's College London, Institute of Psychology, Psychiatry and Neuroscience, London, UK
| | - Richard Dobson
- King's College London, Institute of Psychology, Psychiatry and Neuroscience, London, UK
| | - Alison Baird
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Benjamine Liu
- Department of Psychiatry, University of Oxford, Oxford, UK
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77
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Meri S. Self-nonself discrimination by the complement system. FEBS Lett 2016; 590:2418-34. [PMID: 27393384 DOI: 10.1002/1873-3468.12284] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 06/29/2016] [Accepted: 07/06/2016] [Indexed: 01/09/2023]
Abstract
The alternative pathway (AP) of complement can recognize nonself structures by only two molecules, C3b and factor H. The AP deposits C3b covalently on nonself structures via an amplification system. The actual discrimination is performed by factor H, which has binding sites for polyanions (sialic acids, glycosaminoglycans, phospholipids). This robust recognition of 'self' protects our own intact viable cells and tissues, while activating structures are recognized by default. Foreign targets are opsonized for phagocytosis or killed. Mutations in factor H predispose to severe diseases. In hemolytic uremic syndrome, they promote complement attack against blood cells and vascular endothelial cells and lead, for example, to kidney and brain damage. Even pathogens can exploit factor H. In fact, the ability to bind factor H discriminates most pathogenic microbes from nonpathogenic ones.
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Affiliation(s)
- Seppo Meri
- Immunobiology, Research Programs Unit, Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Finland.,HUSLAB, Helsinki University Hospital, Finland.,Humanitas University, Milan, Italy
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78
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Gesslbauer B, Derler R, Handwerker C, Seles E, Kungl AJ. Exploring the glycosaminoglycan-protein interaction network by glycan-mediated pull-down proteomics. Electrophoresis 2016; 37:1437-47. [PMID: 26970331 DOI: 10.1002/elps.201600043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/29/2016] [Accepted: 02/29/2016] [Indexed: 01/13/2023]
Abstract
Glycosaminoglycans (GAGs) are linear, highly sulfated polysaccharides expressed by almost all animal cells. They occur as soluble molecules, or form proteoglycans by being O-linked to different core proteins on the cell surface and in the extracellular matrix. Due to their ability to interact with diverse proteins and to modulate their biologic functions, GAGs are main drivers of mammalian biology. However, to the present day, the human GAG binding proteome has only been insufficiently explored. The aim of this study was therefore to investigate the human GAG binding proteome of different sources by using the major GAG classes as ligands, and to explore the GAG-binding selectivity of the human plasma proteome. For this purpose, proteins were pulled down from immobilized low molecular weight heparin, heparan sulfate, and dermatan sulfate under different conditions and were identified by nano-LC/MS². Four hundred and fifty eight human GAG binding proteins have been identified, whereas plasma proteins showed clear differences in their GAG-binding specificity/selectivity and affinity. We were able to differentiate between proteins that bound to all three glycan ligands and proteins that showed selective binding to one or two glycan ligands. Moreover, step-gradient salt elution revealed different binding affinities toward different GAG ligands. On top of proteins with well-known GAG-binding properties we have identified formerly unknown GAG binders. Functional annotation of the identified GAG-binding proteins showed clusters of proteins that are involved in a variety of biological processes. The method described here is well suited for identifying GAG-binding proteins and for comparing human subproteomes with respect to binding to different GAG classes.
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Affiliation(s)
- Bernd Gesslbauer
- Institute of Pharmaceutical Sciences, University of Graz, Graz, Austria
| | - Rupert Derler
- Institute of Pharmaceutical Sciences, University of Graz, Graz, Austria
| | | | - Elisabeth Seles
- Institute of Pharmaceutical Sciences, University of Graz, Graz, Austria
| | - Andreas J Kungl
- Institute of Pharmaceutical Sciences, University of Graz, Graz, Austria.,ProtAffin Biotechnologie AG, Graz, Austria
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79
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CFH Variants Affect Structural and Functional Brain Changes and Genetic Risk of Alzheimer's Disease. Neuropsychopharmacology 2016; 41:1034-45. [PMID: 26243271 PMCID: PMC4748428 DOI: 10.1038/npp.2015.232] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 07/08/2015] [Accepted: 07/18/2015] [Indexed: 02/05/2023]
Abstract
The immune response is highly active in Alzheimer's disease (AD). Identification of genetic risk contributed by immune genes to AD may provide essential insight for the prognosis, diagnosis, and treatment of this neurodegenerative disease. In this study, we performed a genetic screening for AD-related top immune genes identified in Europeans in a Chinese cohort, followed by a multiple-stage study focusing on Complement Factor H (CFH) gene. Effects of the risk SNPs on AD-related neuroimaging endophenotypes were evaluated through magnetic resonance imaging scan, and the effects on AD cerebrospinal fluid biomarkers (CSF) and CFH expression changes were measured in aged and AD brain tissues and AD cellular models. Our results showed that the AD-associated top immune genes reported in Europeans (CR1, CD33, CLU, and TREML2) have weak effects in Chinese, whereas CFH showed strong effects. In particular, rs1061170 (P(meta)=5.0 × 10(-4)) and rs800292 (P(meta)=1.3 × 10(-5)) showed robust associations with AD, which were confirmed in multiple world-wide sample sets (4317 cases and 16 795 controls). Rs1061170 (P=2.5 × 10(-3)) and rs800292 (P=4.7 × 10(-4)) risk-allele carriers have an increased entorhinal thickness in their young age and a higher atrophy rate as the disease progresses. Rs800292 risk-allele carriers have higher CSF tau and Aβ levels and severe cognitive decline. CFH expression level, which was affected by the risk-alleles, was increased in AD brains and cellular models. These comprehensive analyses suggested that CFH is an important immune factor in AD and affects multiple pathological changes in early life and during disease progress.
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80
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Ferrington DA, Kapphahn RJ, Leary MM, Atilano SR, Terluk MR, Karunadharma P, Chen GKJ, Ratnapriya R, Swaroop A, Montezuma SR, Kenney MC. Increased retinal mtDNA damage in the CFH variant associated with age-related macular degeneration. Exp Eye Res 2016; 145:269-277. [PMID: 26854823 DOI: 10.1016/j.exer.2016.01.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/25/2016] [Accepted: 01/29/2016] [Indexed: 11/17/2022]
Abstract
Age-related macular degeneration (AMD) is a major cause of blindness among the elderly in the developed world. Genetic analysis of AMD has identified 34 high-risk loci associated with AMD. The genes at these high risk loci belong to diverse biological pathways, suggesting different mechanisms leading to AMD pathogenesis. Thus, therapies targeting a single pathway for all AMD patients will likely not be universally effective. Recent evidence suggests defects in mitochondria (mt) of the retinal pigment epithelium (RPE) may constitute a key pathogenic event in some AMD patients. The purpose of this study is to determine if individuals with a specific genetic background have a greater propensity for mtDNA damage. We used human eyebank tissues from 76 donors with AMD and 42 age-matched controls to determine the extent of mtDNA damage in the RPE that was harvested from the macula using a long extension polymerase chain reaction assay. Genotype analyses were performed for ten common AMD-associated nuclear risk alleles (ARMS2, TNFRSF10A, CFH, C2, C3, APOE, CETP, LIPC, VEGF and COL10A1) and mtDNA haplogroups. Sufficient samples were available for genotype association with mtDNA damage for TNFRSF10A, CFH, CETP, VEGFA, and COL10A1. Our results show that AMD donors carrying the high risk allele for CFH (C) had significantly more mtDNA damage compared with donors having the wild-type genetic profile. The data from an additional 39 donors (12 controls and 27 AMD) genotyped for CFH alleles further supported these findings. Taken together, these studies provide the rationale for a more personalized approach for treating AMD by uncovering a significant correlation between the CFH high risk allele and accelerated mtDNA damage. Patients harboring this genetic risk factor may benefit from therapies that stabilize and protect the mt in the RPE.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Rebecca J Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Michaela M Leary
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Shari R Atilano
- Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
| | - Marcia R Terluk
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Pabalu Karunadharma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | | | - Rinki Ratnapriya
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, Bethesda, MD 20892, USA
| | - Sandra R Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - M Cristina Kenney
- Gavin Herbert Eye Institute, University of California, Irvine, CA, 92697, USA
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81
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Complement pathway biomarkers and age-related macular degeneration. Eye (Lond) 2015; 30:1-14. [PMID: 26493033 DOI: 10.1038/eye.2015.203] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 09/03/2015] [Indexed: 02/07/2023] Open
Abstract
In the age-related macular degeneration (AMD) 'inflammation model', local inflammation plus complement activation contributes to the pathogenesis and progression of the disease. Multiple genetic associations have now been established correlating the risk of development or progression of AMD. Stratifying patients by their AMD genetic profile may facilitate future AMD therapeutic trials resulting in meaningful clinical trial end points with smaller sample sizes and study duration.
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82
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Recalde S, Tortajada A, Subias M, Anter J, Blasco M, Maranta R, Coco R, Pinto S, Noris M, García-Layana A, Rodríguez de Córdoba S. Molecular Basis of Factor H R1210C Association with Ocular and Renal Diseases. J Am Soc Nephrol 2015; 27:1305-11. [PMID: 26376859 DOI: 10.1681/asn.2015050580] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 07/26/2015] [Indexed: 12/23/2022] Open
Abstract
The complement factor H (FH) mutation R1210C, which was described in association with atypical hemolytic uremic syndrome (aHUS), also confers high risk of age-related macular degeneration (AMD) and associates with C3 glomerulopathy (C3G). To reveal the molecular basis of these associations and to provide insight into what determines the disease phenotype in FH-R1210C carriers, we identified FH-R1210C carriers in our aHUS, C3G, and AMD cohorts. Disease status, determined in patients and relatives, revealed an absence of AMD phenotypes in the aHUS cohort and, vice versa, a lack of renal disease in the AMD cohort. These findings were consistent with differences in the R1210C-independent overall risk for aHUS and AMD between mutation carriers developing one pathology or the other. R1210C is an unusual mutation that generates covalent complexes between FH and HSA. Using purified FH proteins and surface plasmon resonance analyses, we demonstrated that formation of these FH-HSA complexes impairs accessibility to all FH functional domains. These data suggest that R1210C is a unique C-terminal FH mutation that behaves as a partial FH deficiency, predisposing individuals to diverse pathologies with distinct underlying pathogenic mechanisms; the final disease outcome is then determined by R1210C-independent genetic risk factors.
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Affiliation(s)
- Sergio Recalde
- Department of Ophthalmology, University Clinic of Navarra, Pamplona, Navarra, Spain
| | - Agustin Tortajada
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, Madrid, Spain
| | - Marta Subias
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, Madrid, Spain
| | - Jaouad Anter
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, Madrid, Spain
| | - Miquel Blasco
- Nephrology and Kidney Transplant Unit, Hospital Clinic, University of Barcelona, Barcelona, Spain
| | - Ramona Maranta
- Mario Negri Institute for Pharmacology Research, Aldo and Cele Daccò Clinical Research Center for Rare Diseases, Ranica, Bergamo, Italy; and
| | - Rosa Coco
- Institute of Applied Ophthalmology, University of Valladolid, Valladolid, Spain
| | - Sheila Pinto
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, Madrid, Spain
| | - Marina Noris
- Mario Negri Institute for Pharmacology Research, Aldo and Cele Daccò Clinical Research Center for Rare Diseases, Ranica, Bergamo, Italy; and
| | | | - Santiago Rodríguez de Córdoba
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, Madrid, Spain;
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83
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Aredo B, Li T, Chen X, Zhang K, Wang CXZ, Gou D, Zhao B, He Y, Ufret-Vincenty RL. A chimeric Cfh transgene leads to increased retinal oxidative stress, inflammation, and accumulation of activated subretinal microglia in mice. Invest Ophthalmol Vis Sci 2015; 56:3427-40. [PMID: 26030099 DOI: 10.1167/iovs.14-16089] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PURPOSE Variants of complement factor H (Cfh) affecting short consensus repeats (SCRs) 6 to 8 increase the risk of age-related macular degeneration. Our aim was to explore the effect of expressing a Cfh variant on the in vivo susceptibility of the retina and RPE to oxidative stress and inflammation, using chimeric Cfh transgenic mice (chCfhTg). METHODS The chCfhTg and age-matched C57BL/6J (B6) mice were subjected to oxidative stress by either normal aging, or by exposure to a combination of oral hydroquinone (0.8% HQ) and increased light. Eyes were collected for immunohistochemistry of RPE-choroid flat mounts and of retinal sections, ELISA, electron microscopy, and RPE/microglia gene expression analysis. RESULTS Aging mice to 2 years led to an increased accumulation of basal laminar deposits, subretinal microglia/macrophages (MG/MΦ) staining for CD16 and for malondialdehyde (MDA), and MDA-modified proteins in the retina in chCfhTg compared to B6 mice. The chCfhTg mice maintained on HQ diet and increased light showed greater deposition of basal laminar deposits, more accumulation of fundus spots suggestive of MG/MΦ, and increased deposition of C3d in the sub-RPE space, compared to controls. In addition, chCfhTg mice demonstrated upregulation of NLRP3, IP-10, CD68, and TREM-2 in the RNA isolates from RPE/MG/MΦ. CONCLUSIONS Expression of a Cfh transgene introducing a variant in SCRs 6 to 8 was sufficient to lead to increased retinal/RPE susceptibility to oxidative stress, a proinflammatory MG/MΦ phenotype, and a proinflammatory RPE/MG/MΦ gene expression profile in a transgenic mouse model. Our data suggest that altered interactions of Cfh with MDA-modified proteins may be relevant in explaining the effects of the Cfh variant.
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Affiliation(s)
- Bogale Aredo
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States
| | - Tao Li
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States 2Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Xiao Chen
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States
| | - Kaiyan Zhang
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States
| | - Cynthia Xin-Zhao Wang
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States
| | - Darlene Gou
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States
| | - Biren Zhao
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States
| | - Yuguang He
- Department of Ophthalmology UT Southwestern Medical Center, Dallas, Texas, United States
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84
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Clark SJ, Bishop PN. Role of Factor H and Related Proteins in Regulating Complement Activation in the Macula, and Relevance to Age-Related Macular Degeneration. J Clin Med 2015; 4:18-31. [PMID: 25729613 PMCID: PMC4340553 DOI: 10.3390/jcm4010018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The recent revolution in age-related macular degeneration (AMD) genetics has demonstrated that genetic alterations affecting the alternative pathway of the complement cascade have a major influence on AMD risk. One of the two most important genetic loci is on chromosome 1 and contains genes encoding complement factor H (FH) and the factor H related proteins (FHR proteins). In macular tissue, especially Bruch’s membrane, relatively high levels of a truncated splice variant of FH called factor H-like protein 1 (FHL-1) are present. Here we discuss how genetic variations may alter the amounts, or by altering their protein sequences, the functions of these proteins. In particular, the common Y402H polymorphism affects the ability of FHL-1 and FH to localize to Bruch’s membrane and the inner choroid because it alters the ability of these complement regulators to bind heparan sulphate (HS) in these structures. In addition, there is an age-related loss of HS from Bruch’s membrane. We hypothesize that a combination of poor binding of the 402H variants of FHL-1 and FH to Bruch’s membrane, combined with a decrease in binding due to age-related HS loss, eventually results in insufficient FHL-1 and FH binding to Bruch’s membrane. This could result in complement activation, inflammation and thereby predispose to AMD.
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Affiliation(s)
- Simon J. Clark
- Centre for Hearing & Vision Research, Institute of Human Development, AV Hill Building, University of Manchester, Oxford Road, Manchester M13 9PL, UK; E-Mail:
- Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Paul N. Bishop
- Centre for Hearing & Vision Research, Institute of Human Development, AV Hill Building, University of Manchester, Oxford Road, Manchester M13 9PL, UK; E-Mail:
- Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
- Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WH, UK
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44-(0)-161-275-5755
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85
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Kent D. The stereotypical molecular cascade in neovascular age-related macular degeneration: the role of dynamic reciprocity. Eye (Lond) 2015; 29:1416-26. [PMID: 26228288 DOI: 10.1038/eye.2015.140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 06/22/2015] [Indexed: 12/15/2022] Open
Abstract
This review summarises our current understanding of the molecular basis of subretinal neovascularisation (SRNV) in age-related macular degeneration (AMD). The term neovascular AMD (NVAMD) is derived from the dominant early clinical features of haemorrhage, fluid, and lipid in the subretinal space (SRS) and the historical role of fluorescein angiography in detecting the presence of NV tissue. However, at the cellular level, SRNV resembles an aberrant but stereotypical tissue repair response that incorporates both an early inflammatory phase and a late fibrotic phase in addition to the neovascular (NV) component that dominates the early clinical presentation. This review will seek not only to highlight the important molecules involved in each of these components but to demonstrate that the development of SRNV has its origins in the earliest events in non-NV AMD pathogenesis. Current evidence suggests that this early-stage pathogenesis is characterised by complement-mediated immune dysregulation, leading to a state of chronic inflammation in the retinal pigment epithelium/Bruch's membrane/choriocapillaris complex. These initial events can be seamlessly and inextricably linked to late-stage development of SRNV in AMD by the process of dynamic reciprocity (DyR), the ongoing bidirectional communication between cells, and their surrounding matrix. Moreover, this correlation between disease onset and eventual outcome is reflected in the temporal and spatial correlation between chronic inflammation, NV, and fibrosis within the reparative microenvironment of the SRS. In summary, the downstream consequences of the earliest dysfunctional molecular events in AMD can result in the late-stage entity we recognize clinically as SRNV and is characterized by a spectrum of predictable, related, and stereotypical processes referred to as DyR.
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Affiliation(s)
- D Kent
- The Vision Clinic, Kilkenny, Ireland.,Faculty of Health and Life Sciences, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
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86
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Kijlstra A, Berendschot TTJM. Age-related macular degeneration: a complementopathy? Ophthalmic Res 2015; 54:64-73. [PMID: 26159686 DOI: 10.1159/000432401] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 05/16/2015] [Indexed: 11/19/2022]
Abstract
Age-related macular degeneration (AMD) is a progressive eye disease affecting many elderly individuals. It has a multifactorial pathogenesis and is associated with numerous environmental (e.g. smoking, light and nutrition) and genetic risk factors. A breakthrough in the mechanisms causing AMD is emerging; the involvement of the alternative pathway of the complement system appears to play a pivotal role. This has led to the statement that AMD is a disease caused by a hyperactive complement system, allowing the term 'complementopathy' to define it more precisely. Abundant evidence includes: the identification of drusen components as activators of complement, immunohistochemical data showing the presence of many species of the complement system in the retinal pigment epithelium-Bruch's membrane-choroidocapillary region of AMD eyes, a strong association of AMD with certain genetic complement protein variants, raised complement levels in blood from AMD patients and the preliminary successful treatments of geographic atrophy with complement factor D (FD) inhibitors. FD is the rate-limiting enzyme of the alternative complement pathway, and is produced by adipose tissue. Recent findings suggest that nutrition may play a role in controlling the level of FD in the circulation. Addressing modifiable risk factors such as smoking and nutrition may thus offer opportunities for the prevention of AMD.
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Affiliation(s)
- Aize Kijlstra
- University Eye Clinic Maastricht, Maastricht, The Netherlands
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87
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Rhoades W, Dickson D, Do DV. Potential role of lampalizumab for treatment of geographic atrophy. Clin Ophthalmol 2015; 9:1049-56. [PMID: 26089637 PMCID: PMC4468985 DOI: 10.2147/opth.s59725] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The purpose of this article is to review the pathways underlying age-related macular degeneration and potential therapeutic targets, focusing on the complement pathway and the recent MAHALO Phase II trial of the investigational drug lampalizumab. This trial was the first to have shown positive results for the treatment of geographic atrophy in age-related macular degeneration. It has potential as a future treatment, and is currently undergoing a Phase III trial.
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Affiliation(s)
- William Rhoades
- Truhlsen Eye Institute, Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Drew Dickson
- Truhlsen Eye Institute, Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Diana V Do
- Truhlsen Eye Institute, Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
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88
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Black JRM, Clark SJ. Age-related macular degeneration: genome-wide association studies to translation. Genet Med 2015; 18:283-9. [PMID: 26020418 PMCID: PMC4823638 DOI: 10.1038/gim.2015.70] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/20/2015] [Indexed: 02/01/2023] Open
Abstract
In recent years, genome-wide association studies (GWAS), which are able to analyze the contribution to disease of genetic variations that are common within a population, have attracted considerable investment. Despite identifying genetic variants for many conditions, they have been criticized for yielding data with minimal clinical utility. However, in this regard, age-related macular degeneration (AMD), the most common form of blindness in the Western world, is a striking exception. Through GWAS, common genetic variants at a number of loci have been discovered. Two loci in particular, including genes of the complement cascade on chromosome 1 and the ARMS2/HTRA1 genes on chromosome 10, have been shown to convey significantly increased susceptibility to developing AMD. Today, although it is possible to screen individuals for a genetic predisposition to the disease, effective interventional strategies for those at risk of developing AMD are scarce. Ongoing research in this area is nonetheless promising. After providing brief overviews of AMD and common disease genetics, we outline the main recent advances in the understanding of AMD, particularly those made through GWAS. Finally, the true merit of these findings and their current and potential translational value is examined.Genet Med 18 4, 283-289.
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Affiliation(s)
- James R M Black
- Faculty of Medicine, Sir Alexander Fleming Building, Imperial College London, London, UK
| | - Simon J Clark
- Centre for Ophthalmology and Vision Sciences, Institute of Human Development, University of Manchester, Manchester, UK
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89
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Abstract
Age-related macular degeneration (AMD) affects approximately one-third of Americans over 70 and is characterized by lipoprotein-rich sub-retinal pigmented epithelium (sub-RPE) deposits. Substantial evidence has emerged that implicates complement factor H (CFH) in the pathogenesis of AMD. Here, we conduct an in vivo analysis to elucidate the role of CFH in AMD pathology. We show that (i) CFH and lipoproteins compete for binding in the sub-RPE extracellular matrix such that decreasing CFH leads to lipoprotein accumulation and sub-RPE deposit formation; and (ii) detrimental complement activation within sub-RPE deposits leads to RPE damage and vision loss. This new understanding of the complicated interactions of CFH in development of AMD-like pathology paves the way for identifying more targeted therapeutic strategies for AMD. Complement factor H (CFH) is a major susceptibility gene for age-related macular degeneration (AMD); however, its impact on AMD pathobiology is unresolved. Here, the role of CFH in the development of AMD pathology in vivo was interrogated by analyzing aged Cfh+/− and Cfh−/− mice fed a high-fat, cholesterol-enriched diet. Strikingly, decreased levels of CFH led to increased sub-retinal pigmented epithelium (sub-RPE) deposit formation, specifically basal laminar deposits, following high-fat diet. Mechanistically, our data show that deposits are due to CFH competition for lipoprotein binding sites in Bruch’s membrane. Interestingly and despite sub-RPE deposit formation occurring in both Cfh+/− and Cfh−/− mice, RPE damage accompanied by loss of vision occurred only in old Cfh+/− mice. We demonstrate that such pathology is a function of excess complement activation in Cfh+/− mice versus complement deficiency in Cfh−/− animals. Due to the CFH-dependent increase in sub-RPE deposit height, we interrogated the potential of CFH as a previously unidentified regulator of Bruch’s membrane lipoprotein binding and show, using human Bruch’s membrane explants, that CFH removes endogenous human lipoproteins in aged donors. Thus, advanced age, high-fat diet, and decreased CFH induce sub-RPE deposit formation leading to complement activation, which contributes to RPE damage and visual function impairment. This new understanding of the complicated interactions of CFH in AMD-like pathology provides an improved foundation for the development of targeted therapies for AMD.
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90
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de Córdoba SR. Complement genetics and susceptibility to inflammatory disease. Lessons from genotype-phenotype correlations. Immunobiology 2015; 221:709-14. [PMID: 26004345 DOI: 10.1016/j.imbio.2015.05.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/06/2015] [Indexed: 10/23/2022]
Abstract
Different genome-wide linkage and association studies performed during the last 15 years have associated mutations and polymorphisms in complement genes with different diseases characterized by tissue damage and inflammation. These are complex disorders in which genetically susceptible individuals usually develop the pathology as a consequence of environmental triggers. Although complement dysregulation is a common feature of these pathologies, how the disease phenotype is determined is only partly understood. One way to advance understanding is to focus the research in the analysis of the peculiar genotype-phenotype correlations that characterize some of these diseases. I will review here how understanding the functional consequences of these disease-associated complement genetic variants is providing us with novel insights into the underpinning complement biology and a better knowledge of the pathogenic mechanisms underlying each of these pathologies. These advances have important therapeutic and diagnostic implications.
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91
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Pouw RB, Vredevoogd DW, Kuijpers TW, Wouters D. Of mice and men: The factor H protein family and complement regulation. Mol Immunol 2015; 67:12-20. [PMID: 25824240 DOI: 10.1016/j.molimm.2015.03.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 10/23/2022]
Abstract
For decades immunological research has relied, with variable success, on mouse models to investigate diseases and possible therapeutic interventions. With the approval of the first therapeutic antibody targeting complement, called eculizumab, as therapy in paroxysmal nocturnal hemoglobinuria (PNH) and more recently atypical hemolytic uremic syndrome (aHUS), the viability of targeting the complement system was demonstrated. The potent, endogenous complement regulators have become of increasing interest as templates for designing and developing new therapeutics. Recently, complement inhibitors based on (parts of) the human complement regulator factor H (FH) are being examined for therapeutic intervention in inflammatory conditions. The first step to evaluate the potency of a new drug is often testing it in a mouse model for the target disease. However, translating results to human conditions requires a good understanding of similarities and, more importantly, differences between the human and mouse complement system and particularly regulation. This review will provide a comprehensive overview of the complement regulator FH and its closely related proteins and current views on their role in mice and men.
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Affiliation(s)
- R B Pouw
- Department of Immunopathology, Sanquin Blood Supply, Division Research and Landsteiner laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands; Department of Pediatric Hematology, Immunology & Infectious Diseases, Emma Children's Hospital, Academic Medical Centre, Amsterdam, the Netherlands.
| | - D W Vredevoogd
- Department of Immunopathology, Sanquin Blood Supply, Division Research and Landsteiner laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
| | - T W Kuijpers
- Department of Pediatric Hematology, Immunology & Infectious Diseases, Emma Children's Hospital, Academic Medical Centre, Amsterdam, the Netherlands; Department of Blood Cell Research, Sanquin Blood Supply, Division Research and Landsteiner laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
| | - D Wouters
- Department of Immunopathology, Sanquin Blood Supply, Division Research and Landsteiner laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
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92
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Schmidt CQ, Kennedy AT, Tham WH. More than just immune evasion: Hijacking complement by Plasmodium falciparum. Mol Immunol 2015; 67:71-84. [PMID: 25816986 DOI: 10.1016/j.molimm.2015.03.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 03/04/2015] [Accepted: 03/04/2015] [Indexed: 12/24/2022]
Abstract
Malaria remains one of the world's deadliest diseases. Plasmodium falciparum is responsible for the most severe and lethal form of human malaria. P. falciparum's life cycle involves two obligate hosts: human and mosquito. From initial entry into these hosts, malaria parasites face the onslaught of the first line of host defence, the complement system. In this review, we discuss the complex interaction between complement and malaria infection in terms of hosts immune responses, parasite survival and pathogenesis of severe forms of malaria. We will focus on the role of complement receptor 1 and its associated polymorphisms in malaria immune complex clearance, as a mediator of parasite rosetting and as an entry receptor for P. falciparum invasion. Complement evasion strategies of P. falciparum parasites will also be highlighted. The sexual forms of the malaria parasites recruit the soluble human complement regulator Factor H to evade complement-mediated killing within the mosquito host. A novel evasion strategy is the deployment of parasite organelles to divert complement attack from infective blood stage parasites. Finally we outline the future challenge to understand the implications of these exploitation mechanisms in the interplay between successful infection of the host and pathogenesis observed in severe malaria.
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Affiliation(s)
- Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Helmholtzstraße 20, Ulm, Germany.
| | - Alexander T Kennedy
- Department of Medical Biology, University of Melbourne and Division of Infection and Immunity, The Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia
| | - Wai-Hong Tham
- Department of Medical Biology, University of Melbourne and Division of Infection and Immunity, The Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia.
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93
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Age-related macular degeneration and the role of the complement system. Mol Immunol 2015; 67:43-50. [PMID: 25804937 DOI: 10.1016/j.molimm.2015.02.032] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 11/21/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of visual impairment. It is characterised by damage to a tissue complex composed of the retinal pigment epithelium, Bruch's membrane and choriocapillaris. In early AMD extracellular debris including drusen accumulates in Bruch's membrane and then in late AMD geographic atrophy and/or neovascularisation develop. Variants in genes encoding components of the alternative pathway of the complement cascade have a major influence on AMD risk, especially at the RCA locus on chromosome 1, which contains CFH and the CFHR genes. Immunohistochemical studies have demonstrated complement components in unaffected and AMD macular tissue. Whilst other factors, including oxidative stress, play important roles in AMD pathogenesis, evidence for the central role played by complement dysregulation is discussed in this review.
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94
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Chavali VRM, Diniz B, Huang J, Ying GS, Sadda SR, Stambolian D. Association of OCT derived drusen measurements with AMD associated-genotypic SNPs in Amish population. J Clin Med 2015; 4:304-317. [PMID: 25893111 PMCID: PMC4398021 DOI: 10.3390/jcm4020304] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose: To investigate the association of optical coherence tomography (OCT)-derived drusen measures in Amish age-related macular degeneration (AMD) patients with known loci for macular degeneration. Methods: Members of the Old Order Amish community in Pennsylvania ages 50 and older were assessed for drusen area, volume and regions of retinal pigment epithelium (RPE) atrophy using a Cirrus High-Definition OCT. Measurements were obtained in the macula region within a central circle (CC) of 3 mm in diameter and a surrounding perifoveal ring (PR) of 3 to 5 mm in diameter using the Cirrus OCT RPE analysis software. Other demographic information, including age, gender and smoking status, were collected. Study subjects were further genotyped to determine their risk for the AMD-associated SNPs in the SYN3, LIPC, ARMS2, C3, CFB, CETP, CFI and CFH genes using TaqMan genotyping assays. The association of genotypes with OCT measures were assessed using linear trend p-values calculated from univariate and multivariate generalized linear models. Results: 432 eyes were included in the analysis. Multivariate analysis (adjusted by age, gender and smoking status) confirmed the known significant association between AMD and macular drusen with the number of CFH risk alleles for the drusen area (the area increased 0.12 mm2 for a risk allele increase, p < 0.01), drusen volume (the volume increased 0.01 mm3 for a risk allele increase, p ≤ 0.05) and the area of RPE atrophy (the area increased 0.43 mm2 for a risk allele increase, p = 0.003). SYN3 risk allele G is significantly associated with larger area PR (the area increased 0.09 mm2 for a risk allele increase, p = 0.03) and larger drusen volume in the central circle (the volume increased 0.01 mm3 for a risk allele increase, p = 0.04). Conclusion: Among the genotyped SNPs tested, the CFH risk genotype appears to play a major role in determining the drusen phenotype in the Amish AMD population.
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Affiliation(s)
- Venkata Ramana Murthy Chavali
- Department of Ophthalmology, University of Pennsylvania, 313B Stellar-Chance Labs, 422 Curie Blvd., Philadelphia, PA 19104, USA; E-Mail:
| | - Bruno Diniz
- Doheny Eye Institute, Los Angeles, CA 90033, USA; E-Mails: (B.D.); (S.R.S.)
- Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo 09920, Brazil
| | - Jiayan Huang
- Center for Preventive Ophthalmology and Biostatistics, Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA; E-Mails: (J.H.); (G.-S.Y.)
| | - Gui-Shuang Ying
- Center for Preventive Ophthalmology and Biostatistics, Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA; E-Mails: (J.H.); (G.-S.Y.)
| | - SriniVas R. Sadda
- Doheny Eye Institute, Los Angeles, CA 90033, USA; E-Mails: (B.D.); (S.R.S.)
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA
| | - Dwight Stambolian
- Department of Ophthalmology, University of Pennsylvania, 313B Stellar-Chance Labs, 422 Curie Blvd., Philadelphia, PA 19104, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-215-898-0305; Fax: +1-215-573-6728
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95
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Langford-Smith A, Day AJ, Bishop PN, Clark SJ. Complementing the Sugar Code: Role of GAGs and Sialic Acid in Complement Regulation. Front Immunol 2015; 6:25. [PMID: 25699044 PMCID: PMC4313701 DOI: 10.3389/fimmu.2015.00025] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/12/2015] [Indexed: 01/15/2023] Open
Abstract
Sugar molecules play a vital role on both microbial and mammalian cells, where they are involved in cellular communication, govern microbial virulence, and modulate host immunity and inflammatory responses. The complement cascade, as part of a host's innate immune system, is a potent weapon against invading bacteria but has to be tightly regulated to prevent inappropriate attack and damage to host tissues. A number of complement regulators, such as factor H and properdin, interact with sugar molecules, such as glycosaminoglycans (GAGs) and sialic acid, on host and pathogen membranes and direct the appropriate complement response by either promoting the binding of complement activators or inhibitors. The binding of these complement regulators to sugar molecules can vary from location to location, due to their different specificities and because distinct structural and functional subpopulations of sugars are found in different human organs, such as the brain, kidney, and eye. This review will cover recent studies that have provided important new insights into the role of GAGs and sialic acid in complement regulation and how sugar recognition may be compromised in disease.
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Affiliation(s)
- Alex Langford-Smith
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester , Manchester , UK
| | - Anthony J Day
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester , Manchester , UK
| | - Paul N Bishop
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester , Manchester , UK ; Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK ; Manchester Academic Health Science Centre, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK ; Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK
| | - Simon J Clark
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester , Manchester , UK ; Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK
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96
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Blaum BS, Hannan JP, Herbert AP, Kavanagh D, Uhrín D, Stehle T. Structural basis for sialic acid-mediated self-recognition by complement factor H. Nat Chem Biol 2014; 11:77-82. [PMID: 25402769 DOI: 10.1038/nchembio.1696] [Citation(s) in RCA: 212] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 10/02/2014] [Indexed: 12/25/2022]
Abstract
The serum protein complement factor H (FH) ensures downregulation of the complement alternative pathway, a branch of innate immunity, upon interaction with specific glycans on host cell surfaces. Using ligand-based NMR, we screened a comprehensive set of sialylated glycans for binding to FH and solved the crystal structure of a ternary complex formed by the two C-terminal domains of FH, a sialylated trisaccharide and the complement C3b thioester-containing domain. Key residues in the sialic acid binding site are conserved from mice to men, and residues linked to atypical hemolytic uremic syndrome cluster within this binding site, suggesting a possible role for sialic acid as a host marker also in other mammals and a critical role in human renal complement homeostasis. Unexpectedly, the FH sialic acid binding site is structurally homologous to the binding sites of two evolutionarily unrelated proteins. The crystal structure also advances our understanding of bacterial immune evasion strategies.
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Affiliation(s)
- Bärbel S Blaum
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jonathan P Hannan
- Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | | | - David Kavanagh
- Institute of Genetic Medicine, International Centre for Life, Newcastle upon Tyne, UK
| | - Dušan Uhrín
- The School of Chemistry, University of Edinburgh, Scotland, UK
| | - Thilo Stehle
- 1] Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany. [2] Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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97
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Clark SJ, Schmidt CQ, White AM, Hakobyan S, Morgan BP, Bishop PN. Identification of factor H-like protein 1 as the predominant complement regulator in Bruch's membrane: implications for age-related macular degeneration. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 193:4962-70. [PMID: 25305316 PMCID: PMC4225158 DOI: 10.4049/jimmunol.1401613] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The tight regulation of innate immunity on extracellular matrix (ECM) is a vital part of immune homeostasis throughout the human body, and disruption to this regulation in the eye is thought to contribute directly to the progression of age-related macular degeneration (AMD). The plasma complement regulator factor H (FH) is thought to be the main regulator that protects ECM against damaging complement activation. However, in the present study we demonstrate that a truncated form of FH, called FH-like protein 1 (FHL-1), is the main regulatory protein in the layer of ECM under human retina, called Bruch's membrane. Bruch's membrane is a major site of AMD disease pathogenesis and where drusen, the hallmark lesions of AMD, form. We show that FHL-1 can passively diffuse through Bruch's membrane, whereas the full sized, glycosylated, FH cannot. FHL-1 is largely bound to Bruch's membrane through interactions with heparan sulfate, and we show that the common Y402H polymorphism in the CFH gene, associated with an increased risk of AMD, reduces the binding of FHL-1 to this heparan sulfate. We also show that FHL-1 is retained in drusen whereas FH coats the periphery of the lesions, perhaps inhibiting their clearance. Our results identify a novel mechanism of complement regulation in the human eye, which highlights potential new avenues for therapeutic strategies.
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Affiliation(s)
- Simon J Clark
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester, Manchester M13 9PT, United Kingdom; Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, United Kingdom;
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, 89081 Ulm, Germany
| | - Anne M White
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester, Manchester M13 9PT, United Kingdom; Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, United Kingdom
| | - Svetlana Hakobyan
- Complement Biology Group, Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom; and
| | - B Paul Morgan
- Complement Biology Group, Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom; and
| | - Paul N Bishop
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester, Manchester M13 9PT, United Kingdom; Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, United Kingdom; Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom
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98
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Warwick A, Khandhadia S, Ennis S, Lotery A. Age-Related Macular Degeneration: A Disease of Systemic or Local Complement Dysregulation? J Clin Med 2014; 3:1234-57. [PMID: 26237601 PMCID: PMC4470180 DOI: 10.3390/jcm3041234] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 01/25/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in developed countries. The role of complement in the development of AMD is now well-established. While some studies show evidence of complement dysregulation within the eye, others have demonstrated elevated systemic complement activation in association with AMD. It is unclear which one is the primary driver of disease. This has important implications for designing novel complement-based AMD therapies. We present a summary of the current literature and suggest that intraocular rather than systemic modulation of complement may prove more effective.
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Affiliation(s)
- Alasdair Warwick
- Clinical Neurosciences Research Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
| | - Samir Khandhadia
- Eye Unit, University Southampton NHS Trust, Southampton SO16 6YD, UK.
| | - Sarah Ennis
- Genomic Informatics, Human Genetics & Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
| | - Andrew Lotery
- Clinical Neurosciences Research Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
- Eye Unit, University Southampton NHS Trust, Southampton SO16 6YD, UK.
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99
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Ding JD, Kelly U, Landowski M, Toomey CB, Groelle M, Miller C, Smith SG, Klingeborn M, Singhapricha T, Jiang H, Frank MM, Bowes Rickman C. Expression of human complement factor H prevents age-related macular degeneration-like retina damage and kidney abnormalities in aged Cfh knockout mice. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:29-42. [PMID: 25447048 DOI: 10.1016/j.ajpath.2014.08.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/21/2014] [Accepted: 08/27/2014] [Indexed: 01/17/2023]
Abstract
Complement factor H (CFH) is an important regulatory protein in the alternative pathway of the complement system, and CFH polymorphisms increase the genetic risk of age-related macular degeneration dramatically. These same human CFH variants have also been associated with dense deposit disease. To mechanistically study the function of CFH in the pathogenesis of these diseases, we created transgenic mouse lines using human CFH bacterial artificial chromosomes expressing full-length human CFH variants and crossed these to Cfh knockout (Cfh(-/-)) mice. Human CFH protein inhibited cleavage of mouse complement component 3 and factor B in plasma and in retinal pigment epithelium/choroid/sclera, establishing that human CFH regulates activation of the mouse alternative pathway. One of the mouse lines, which express relatively higher levels of CFH, demonstrated functional and structural protection of the retina owing to the Cfh deletion. Impaired visual function, detected as a deficit in the scotopic electroretinographic response, was improved in this transgenic mouse line compared with Cfh(-/-) mice, and transgenics had a thicker outer nuclear layer and less sub-retinal pigment epithelium deposit accumulation. In addition, expression of human CFH also completely protected the mice from developing kidney abnormalities associated with loss of CFH. These humanized CFH mice present a valuable model for study of the molecular mechanisms of age-related macular degeneration and dense deposit disease and for testing therapeutic targets.
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Affiliation(s)
- Jin-Dong Ding
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Una Kelly
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Michael Landowski
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Christopher B Toomey
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina; Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
| | - Marybeth Groelle
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Chelsey Miller
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Stephanie G Smith
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Mikael Klingeborn
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Terry Singhapricha
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | - Haixiang Jiang
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina
| | - Michael M Frank
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina
| | - Catherine Bowes Rickman
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina; Department of Cell Biology, Duke University Medical Center, Durham, North Carolina.
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100
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Mullins RF, Schoo DP, Sohn EH, Flamme-Wiese MJ, Workamelahu G, Johnston RM, Wang K, Tucker BA, Stone EM. The membrane attack complex in aging human choriocapillaris: relationship to macular degeneration and choroidal thinning. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:3142-53. [PMID: 25204844 DOI: 10.1016/j.ajpath.2014.07.017] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/18/2014] [Accepted: 07/10/2014] [Indexed: 01/19/2023]
Abstract
Age-related macular degeneration (AMD) is a common disease that can result in severe visual impairment. Abnormal regulation of the complement system has been implicated in its pathogenesis, and CFH polymorphisms contribute substantially to risk. How these polymorphisms exert their effects is poorly understood. We performed enzyme-linked immunosorbent assay (ELISA) analysis on young, aged, and AMD choroids to determine the abundance of the membrane attack complex (MAC) and performed immunofluorescence studies on eyes from 117 donors to evaluate the MAC in aging, early AMD, and advanced AMD. Morphometric studies were performed on eyes with high- or low-risk CFH genotypes. ELISA confirmed that MAC increases significantly with aging and with AMD. MAC was localized to Bruch's membrane and the choriocapillaris and was detectable at low levels as early as 5 years of age. Hard drusen were labeled with anti-MAC antibody, but large or confluent drusen and basal deposits were generally unlabeled. Labeling of retinal pigment epithelium was observed in some cases of advanced AMD, but not in early disease. Eyes homozygous for the high-risk CFH genotype had thinner choroids than low-risk homozygotes (P < 0.05). These findings suggest that increased complement activation in AMD and in high-risk genotypes can lead to loss of endothelial cells in early AMD. Treatments to protect the choriocapillaris in early AMD are needed.
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Affiliation(s)
- Robert F Mullins
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa.
| | - Desi P Schoo
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa
| | - Elliott H Sohn
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa
| | - Miles J Flamme-Wiese
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa
| | - Grefachew Workamelahu
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa
| | - Rebecca M Johnston
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa
| | - Kai Wang
- Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa; Department of Biostatistics, The University of Iowa, Iowa City, Iowa
| | - Budd A Tucker
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa
| | - Edwin M Stone
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa; Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, Iowa
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