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Hristodorov D, Lohoff T, Luneborg N, Mulder GJ, Clark SJ. Investing in vision: Innovation in retinal therapeutics and the influence on venture capital investment. Prog Retin Eye Res 2024; 99:101243. [PMID: 38218527 DOI: 10.1016/j.preteyeres.2024.101243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 01/15/2024]
Abstract
Since the groundbreaking approval of the first anti-VEGF therapy in 2004, the retinal therapeutics field has undergone a remarkable transformation, witnessing a surge in novel, disease-modifying therapeutics for a broad spectrum of retinal diseases, extending beyond exudative VEGF-driven conditions. The surge in scientific advancement and the pressing, unmet, medical need have captured the attention of venture capital investors, who have collectively invested close to $10 billion in research and development of new retinal therapeutics between 2004 and 2023. Notably, the field of exudative diseases has gradually shifted away from trying to outcompete anti-VEGF therapeutics towards lowering the overall treatment burden by reducing injection frequency. Simultaneously, a new era has emerged in the non-exudative field, targeting prevalent conditions like dry AMD and rare indications such as Retinitis pigmentosa. This has led to promising drug candidates in development, culminating in the landmark approval of Luxturna for a rare form of Retinitis pigmentosa. The validation of new mechanisms, such as the complement pathway in dry AMD has paved the way for the approvals of Syvovre (Apellis) and Izervay (Iveric/Astellas), marking the first two therapies for this condition. In this comprehensive review, we share our view on the cumulative lessons from the past two decades in developing retinal therapeutics, covering both positive achievements and challenges. We also contextualize the investments, strategic partnering deals, and acquisitions of biotech companies, pharmaceutical companies venture capital investors in retinal therapeutics, respectively. Finally, we provide an outlook and potentially a forward-looking roadmap on novel retinal therapeutics, highlighting the emergence of potential new intervention strategies, such as cell-based therapies, gene editing, and combination therapies. We conclude that upcoming developments have the potential to further stimulate venture capital investments, which ultimately could facilitate the development and delivery of new therapies to patients in need.
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Affiliation(s)
| | | | | | | | - Simon J Clark
- Institute for Ophthalmic Research, Department for Ophthalmology, University Medical Center, Eberhard Karls University of Tübingen, Tübingen, Germany; University Eye Clinic, University Hospital Tübingen, Tübingen, Germany; Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, UK
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2
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Yee WX, Barnes G, Lavender H, Tang CM. Meningococcal factor H-binding protein: implications for disease susceptibility, virulence, and vaccines. Trends Microbiol 2023; 31:805-815. [PMID: 36941192 PMCID: PMC10914675 DOI: 10.1016/j.tim.2023.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/23/2023]
Abstract
Neisseria meningitidis is a human-adapted pathogen that causes meningitis and sepsis worldwide. N. meningitidis factor H-binding protein (fHbp) provides a mechanism for immune evasion by binding human complement factor H (CFH) to protect it from complement-mediated killing. Here, we discuss features of fHbp which enable it to engage human CFH (hCFH), and the regulation of fHbp expression. Studies of host susceptibility and bacterial genome-wide association studies (GWAS) highlight the importance of the interaction between fHbp and CFH and other complement factors, such as CFHR3, on the development of invasive meningococcal disease (IMD). Understanding the basis of fHbp:CFH interactions has also informed the design of next-generation vaccines as fHbp is a protective antigen. Structure-informed refinement of fHbp vaccines will help to combat the threat posed by the meningococcus, and accelerate the elimination of IMD.
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Affiliation(s)
- Wearn-Xin Yee
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Grace Barnes
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Hayley Lavender
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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3
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Hammadi S, Tzoumas N, Ferrara M, Meschede IP, Lo K, Harris C, Lako M, Steel DH. Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration. J Clin Med 2023; 12:2870. [PMID: 37109207 PMCID: PMC10145879 DOI: 10.3390/jcm12082870] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
The complement system is crucial for immune surveillance, providing the body's first line of defence against pathogens. However, an imbalance in its regulators can lead to inappropriate overactivation, resulting in diseases such as age-related macular degeneration (AMD), a leading cause of irreversible blindness globally affecting around 200 million people. Complement activation in AMD is believed to begin in the choriocapillaris, but it also plays a critical role in the subretinal and retinal pigment epithelium (RPE) spaces. Bruch's membrane (BrM) acts as a barrier between the retina/RPE and choroid, hindering complement protein diffusion. This impediment increases with age and AMD, leading to compartmentalisation of complement activation. In this review, we comprehensively examine the structure and function of BrM, including its age-related changes visible through in vivo imaging, and the consequences of complement dysfunction on AMD pathogenesis. We also explore the potential and limitations of various delivery routes (systemic, intravitreal, subretinal, and suprachoroidal) for safe and effective delivery of conventional and gene therapy-based complement inhibitors to treat AMD. Further research is needed to understand the diffusion of complement proteins across BrM and optimise therapeutic delivery to the retina.
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Affiliation(s)
- Sarah Hammadi
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Nikolaos Tzoumas
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
| | | | - Ingrid Porpino Meschede
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Katharina Lo
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Claire Harris
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Majlinda Lako
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David H. Steel
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
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4
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Quintana JI, Atxabal U, Unione L, Ardá A, Jiménez-Barbero J. Exploring multivalent carbohydrate-protein interactions by NMR. Chem Soc Rev 2023; 52:1591-1613. [PMID: 36753338 PMCID: PMC9987413 DOI: 10.1039/d2cs00983h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Indexed: 02/09/2023]
Abstract
Nuclear Magnetic Resonance (NMR) has been widely employed to assess diverse features of glycan-protein molecular recognition events. Different types of qualitative and quantitative information at different degrees of resolution and complexity can be extracted from the proper application of the available NMR-techniques. In fact, affinity, structural, kinetic, conformational, and dynamic characteristics of the binding process are available. Nevertheless, except in particular cases, the affinity of lectin-sugar interactions is weak, mostly at the low mM range. This feature is overcome in biological processes by using multivalency, thus augmenting the strength of the binding. However, the application of NMR methods to monitor multivalent lectin-glycan interactions is intrinsically challenging. It is well known that when large macromolecular complexes are formed, the NMR signals disappear from the NMR spectrum, due to the existence of fast transverse relaxation, related to the large size and exchange features. Indeed, at the heart of the molecular recognition event, the associated free-bound chemical exchange process for both partners takes place in a particular timescale. Thus, these factors have to be considered and overcome. In this review article, we have distinguished, in a subjective manner, the existence of multivalent presentations in the glycan or in the lectin. From the glycan perspective, we have also considered whether multiple epitopes of a given ligand are presented in the same linear chain of a saccharide (i.e., poly-LacNAc oligosaccharides) or decorating different arms of a multiantennae scaffold, either natural (as in multiantennae N-glycans) or synthetic (of dendrimer or polymer nature). From the lectin perspective, the presence of an individual binding site at every monomer of a multimeric lectin may also have key consequences for the binding event at different levels of complexity.
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Affiliation(s)
- Jon I Quintana
- CICbioGUNE, Basque Research & Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Bizkaia, Spain.
| | - Unai Atxabal
- CICbioGUNE, Basque Research & Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Bizkaia, Spain.
| | - Luca Unione
- CICbioGUNE, Basque Research & Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Bizkaia, Spain.
- Ikerbasque, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Bizkaia, Spain
| | - Ana Ardá
- CICbioGUNE, Basque Research & Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Bizkaia, Spain.
- Ikerbasque, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Bizkaia, Spain
| | - Jesús Jiménez-Barbero
- CICbioGUNE, Basque Research & Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Bizkaia, Spain.
- Ikerbasque, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Bizkaia, Spain
- Department of Organic Chemistry, II Faculty of Science and Technology, EHU-UPV, 48940 Leioa, Spain
- Centro de Investigación Biomédica En Red de Enfermedades Respiratorias, Madrid, Spain
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5
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Lucientes-Continente L, Márquez-Tirado B, Goicoechea de Jorge E. The Factor H protein family: The switchers of the complement alternative pathway. Immunol Rev 2023; 313:25-45. [PMID: 36382387 PMCID: PMC10099856 DOI: 10.1111/imr.13166] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The factor H (FH) protein family is emerging as a complex network of proteins controlling the fate of the complement alternative pathway (AP) and dictating susceptibility to a wide range of diseases including infectious, inflammatory, autoimmune, and degenerative diseases and cancer. Composed, in man, of seven highly related proteins, FH, factor H-like 1, and 5 factor H-related proteins, some of the FH family proteins are devoted to down-regulating the AP, while others exert an opposite function by promoting AP activation. Recent findings have provided insights into the molecular mechanisms defining their biological roles and their pathogenicity, illustrating the relevance that the balance between the regulators and the activators within this protein family has in defining the outcome of complement activation on cell surfaces. In this review we will discuss the emerging roles of the factor H protein family, their impact in the complement cascade, and their involvement in the pathogenesis of complement-mediated diseases associated with the AP dysregulation.
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Affiliation(s)
- Laura Lucientes-Continente
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University and Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Bárbara Márquez-Tirado
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University and Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Elena Goicoechea de Jorge
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University and Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
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6
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Shaughnessy J, Chabeda A, Lewis LA, Ram S. Alternative pathway amplification and infections. Immunol Rev 2023; 313:162-180. [PMID: 36336911 DOI: 10.1111/imr.13160] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The alternative pathway (AP) is the phylogenetically oldest arm of the complement system and may have evolved to mark pathogens for elimination by phagocytes. Studies using purified AP proteins or AP-specific serum showed that C3b amplification on bacteria commenced following a lag phase of about 5 min and was highly dependent on the concentration of complement. Most pathogens have evolved several elegant mechanisms to evade complement, including expressing proteases that degrade AP proteins and secreting proteins that block function of C3 convertases. In an example of convergent evolution, many microbes recruit the AP inhibitor factor H (FH) using molecular mechanisms that mimic FH interactions with host cells. In most instances, the AP serves to amplify C3b deposited on microbes by the classical pathway (CP). The role of properdin on microbes appears to be restricted to stabilization of C3 convertases; scant evidence exists for its role as an initiator of the AP on pathogens in the context of serum. Therapeutic complement inhibition carries with it an increased risk of infection. Antibody (Ab)-dependent AP activation may be critical for complement activation by vaccine-elicited Ab when the CP is blocked, and its molecular mechanism is discussed.
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Affiliation(s)
- Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Aleyo Chabeda
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Lisa A Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
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7
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Biggs RM, Makou E, Lauder S, Herbert AP, Barlow PN, Katti SK. An Evaluation of the Complement-Regulating Activities of Human Complement Factor H (FH) Variants Associated With Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2022; 63:30. [DOI: 10.1167/iovs.63.12.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Robyn M. Biggs
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Scott Lauder
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
| | - Andrew P. Herbert
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Paul N. Barlow
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
- School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Suresh K. Katti
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
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8
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Yokoo T, Tanabe A, Yoshida Y, Caaveiro JMM, Nakakido M, Ikeda Y, Fujimura Y, Matsumoto M, Entzminger K, Maruyama T, Okumura CJ, Nangaku M, Tsumoto K. Antibody recognition of complement Factor H reveals a flexible loop involved in Atypical Hemolytic Uremic Syndrome pathogenesis. J Biol Chem 2022; 298:101962. [PMID: 35452676 PMCID: PMC9127587 DOI: 10.1016/j.jbc.2022.101962] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 04/15/2022] [Accepted: 04/16/2022] [Indexed: 11/28/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a disease associated with dysregulation of the immune complement system, especially of the alternative pathway (AP). Complement factor H (CFH), consisting of 20 domains called CCP1-20, downregulates the AP as a cofactor for mediating C3 inactivation by complement factor I (CFI). However, anomalies related to CFH are known to cause excessive complement activation and cytotoxicity. In aHUS, mutations and the presence of anti-CFH autoantibodies (AAbs) have been reported as plausible causes of CFH dysfunction, and it is known that CFH-related aHUS carries a high probability of end-stage renal disease. Elucidating the detailed functions of CFH at the molecular level will help to understand aHUS pathogenesis. Herein, we used biophysical data to reveal that a heavy-chain antibody fragment, termed VHH4, recognized CFH with high affinity. Hemolytic assays also indicated that VHH4 disrupted the protective function of CFH on sheep erythrocytes. Furthermore, X-ray crystallography revealed that VHH4 recognized the Leu1181-Leu1189CCP20 loop, a known anti-CFH AAbs epitope. We next analyzed the dynamics of the C-terminal region of CFH, and showed that the epitopes recognized by anti-CFH AAbs and VHH4 were the most flexible regions in CCP18-20. Finally, we conducted mutation analyses to elucidate the mechanism of VHH4 recognition of CFH, and revealed that VHH4 inserts Trp1183CCP20 residue of CFH into the pocket formed by the complementary determining region 3 loop. These results suggested that anti-CFH AAbs may adopt a similar molecular mechanism to recognize the flexible loop of Leu1181-Leu1189CCP20, leading to aHUS pathogenesis.
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Affiliation(s)
- Takanori Yokoo
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Aki Tanabe
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yoko Yoshida
- Division of Nephrology and Endocrinology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Jose M M Caaveiro
- Department of Global Healthcare, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Makoto Nakakido
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
| | - Yoichiro Ikeda
- Division of Nephrology and Endocrinology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yoshihiro Fujimura
- Department of Blood Transfusion Medicine, Nara Medical University, 840, Shijo-Cho, Kashihara, Nara, 634-8521, Japan
| | - Masanori Matsumoto
- Department of Blood Transfusion Medicine, Nara Medical University, 840, Shijo-Cho, Kashihara, Nara, 634-8521, Japan
| | - Kevin Entzminger
- Abwiz Bio Inc, 9823 Pacific Heights Blvd, Ste J, San Diego, California, 92121, USA
| | - Toshiaki Maruyama
- Abwiz Bio Inc, 9823 Pacific Heights Blvd, Ste J, San Diego, California, 92121, USA
| | - C J Okumura
- Abwiz Bio Inc, 9823 Pacific Heights Blvd, Ste J, San Diego, California, 92121, USA
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Kouhei Tsumoto
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan; The institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.
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9
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Ren Z, Perkins SJ, Love-Gregory L, Atkinson JP, Java A. Clinicopathologic Implications of Complement Genetic Variants in Kidney Transplantation. Front Med (Lausanne) 2021; 8:775280. [PMID: 34912830 PMCID: PMC8666976 DOI: 10.3389/fmed.2021.775280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/08/2021] [Indexed: 12/23/2022] Open
Abstract
Genetic testing has uncovered rare variants in complement proteins associated with thrombotic microangiopathy (TMA) and C3 glomerulopathy (C3G). Approximately 50% are classified as variants of uncertain significance (VUS). Clinical risk assessment of patients carrying a VUS remains challenging primarily due to a lack of functional information, especially in the context of multiple confounding factors in the setting of kidney transplantation. Our objective was to evaluate the clinicopathologic significance of genetic variants in TMA and C3G in a kidney transplant cohort. We used whole exome next-generation sequencing to analyze complement genes in 76 patients, comprising 60 patients with a TMA and 16 with C3G. Ten variants in complement factor H (CFH) were identified; of these, four were known to be pathogenic, one was likely benign and five were classified as a VUS (I372V, I453L, G918E, T956M, L1207I). Each VUS was subjected to a structural analysis and was recombinantly produced; if expressed, its function was then characterized relative to the wild-type (WT) protein. Our data indicate that I372V, I453L, and G918E were deleterious while T956M and L1207I demonstrated normal functional activity. Four common polymorphisms in CFH (E936D, N1050Y, I1059T, Q1143E) were also characterized. We also assessed a family with a pathogenic variant in membrane cofactor protein (MCP) in addition to CFH with a unique clinical presentation featuring valvular dysfunction. Our analyses helped to determine disease etiology and defined the recurrence risk after kidney transplant, thereby facilitating clinical decision making for our patients. This work further illustrates the limitations of the prediction models and highlights the importance of conducting functional analysis of genetic variants particularly in a complex clinicopathologic scenario such as kidney transplantation.
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Affiliation(s)
- Zhen Ren
- Division of Allergy and Immunology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Stephen J. Perkins
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Latisha Love-Gregory
- Genomic and Pathology Services, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
| | - John P. Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Anuja Java
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
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Pappas CM, Zouache MA, Matthews S, Faust CD, Hageman JL, Williams BL, Richards BT, Hageman GS. Protective chromosome 1q32 haplotypes mitigate risk for age-related macular degeneration associated with the CFH-CFHR5 and ARMS2/HTRA1 loci. Hum Genomics 2021; 15:60. [PMID: 34563268 PMCID: PMC8466924 DOI: 10.1186/s40246-021-00359-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/07/2021] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Single-variant associations with age-related macular degeneration (AMD), one of the most prevalent causes of irreversible vision loss worldwide, have been studied extensively. However, because of a lack of refinement of these associations, there remains considerable ambiguity regarding what constitutes genetic risk and/or protection for this disease, and how genetic combinations affect this risk. In this study, we consider the two most common and strongly AMD-associated loci, the CFH-CFHR5 region on chromosome 1q32 (Chr1 locus) and ARMS2/HTRA1 gene on chromosome 10q26 (Chr10 locus). RESULTS By refining associations within the CFH-CFHR5 locus, we show that all genetic protection against the development of AMD in this region is described by the combination of the amino acid-altering variant CFH I62V (rs800292) and genetic deletion of CFHR3/1. Haplotypes based on CFH I62V, a CFHR3/1 deletion tagging SNP and the risk variant CFH Y402H are associated with either risk, protection or neutrality for AMD and capture more than 99% of control- and case-associated chromosomes. We find that genetic combinations of CFH-CFHR5 haplotypes (diplotypes) strongly influence AMD susceptibility and that individuals with risk/protective diplotypes are substantially protected against the development of disease. Finally, we demonstrate that AMD risk in the ARMS2/HTRA1 locus is also mitigated by combinations of CFH-CFHR5 haplotypes, with Chr10 risk variants essentially neutralized by protective CFH-CFHR5 haplotypes. CONCLUSIONS Our study highlights the importance of considering protective CFH-CFHR5 haplotypes when assessing genetic susceptibility for AMD. It establishes a framework that describes the full spectrum of AMD susceptibility using an optimal set of single-nucleotide polymorphisms with known functional consequences. It also indicates that protective or preventive complement-directed therapies targeting AMD driven by CFH-CFHR5 risk haplotypes may also be effective when AMD is driven by ARMS2/HTRA1 risk variants.
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Affiliation(s)
- Chris M Pappas
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA
| | - Moussa A Zouache
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA.
| | - Stacie Matthews
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA
| | - Caitlin D Faust
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA
| | - Jill L Hageman
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA
| | - Brandi L Williams
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA
| | - Burt T Richards
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA
| | - Gregory S Hageman
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT, 84132, USA.
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11
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Puy C, Pang J, Reitsma SE, Lorentz CU, Tucker EI, Gailani D, Gruber A, Lupu F, McCarty OJT. Cross-Talk between the Complement Pathway and the Contact Activation System of Coagulation: Activated Factor XI Neutralizes Complement Factor H. THE JOURNAL OF IMMUNOLOGY 2021; 206:1784-1792. [PMID: 33811105 DOI: 10.4049/jimmunol.2000398] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 02/11/2021] [Indexed: 12/17/2022]
Abstract
Complement factor H (CFH) is the major inhibitor of the alternative pathway of the complement system and is structurally related to beta2-glycoprotein I, which itself is known to bind to ligands, including coagulation factor XI (FXI). We observed reduced complement activation when FXI activation was inhibited in a baboon model of lethal systemic inflammation, suggesting cross-talk between FXI and the complement cascade. It is unknown whether FXI or its activated form, activated FXI (FXIa), directly interacts with the complement system. We explored whether FXI could interact with and inhibit the activity of CFH. We found that FXIa neutralized CFH by cleavage of the R341/R342 bonds. FXIa reduced the capacity of CFH to enhance the cleavage of C3b by factor I and the decay of C3bBb. The binding of CFH to human endothelial cells was also reduced after incubating CFH with FXIa. The addition of either short- or long-chain polyphosphate enhanced the capacity of FXIa to cleave CFH. FXIa also cleaved CFH that was present on endothelial cells and in the secretome from blood platelets. The generation of FXIa in plasma induced the cleavage of CFH. Moreover, FXIa reduced the cleavage of C3b by factor I in serum. Conversely, we observed that CFH inhibited FXI activation by either thrombin or FXIIa. Our study provides, to our knowledge, a novel molecular link between the contact pathway of coagulation and the complement system. These results suggest that FXIa generation enhances the activity of the complement system and thus may potentiate the immune response.
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Affiliation(s)
- Cristina Puy
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239; .,Division of Hematology and Medical Oncology, School of Medicine, Oregon Health & Science University, Portland, OR 97239
| | - Jiaqing Pang
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239
| | - Stéphanie E Reitsma
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239
| | - Christina U Lorentz
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239.,Aronora, Inc., Portland, OR 97239
| | - Erik I Tucker
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239.,Aronora, Inc., Portland, OR 97239
| | - David Gailani
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232; and
| | - András Gruber
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239.,Division of Hematology and Medical Oncology, School of Medicine, Oregon Health & Science University, Portland, OR 97239.,Aronora, Inc., Portland, OR 97239
| | - Florea Lupu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104
| | - Owen J T McCarty
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239.,Division of Hematology and Medical Oncology, School of Medicine, Oregon Health & Science University, Portland, OR 97239
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12
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Interlink between Inflammation and Oxidative Stress in Age-Related Macular Degeneration: Role of Complement Factor H. Biomedicines 2021; 9:biomedicines9070763. [PMID: 34209418 PMCID: PMC8301356 DOI: 10.3390/biomedicines9070763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 12/16/2022] Open
Abstract
Age-related macular degeneration (AMD) heads the list of legal blindness among the elderly population in developed countries. Due to the complex nature of the retina and the variety of risk factors and mechanisms involved, the molecular pathways underlying AMD are not yet fully defined. Persistent low-grade inflammation and oxidative stress eventually lead to retinal pigment epithelium dysfunction and outer blood-retinal barrier (oBRB) breakdown. The identification of AMD susceptibility genes encoding complement factors, and the presence of inflammatory mediators in drusen, the hallmark deposits of AMD, supports the notion that immune-mediated processes are major drivers of AMD pathobiology. Complement factor H (FH), the main regulator of the alternative pathway of the complement system, may have a key contribution in the pathogenesis of AMD as it is able to regulate both inflammatory and oxidative stress responses in the oBRB. Indeed, genetic variants in the CFH gene account for the strongest genetic risk factors for AMD. In this review, we focus on the roles of inflammation and oxidative stress and their connection with FH and related proteins as regulators of both phenomena in the context of AMD.
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13
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Day AJ. A Personal Tribute to Robert B. Sim with Reflections on Our Work Together on Factor H. Viruses 2021; 13:v13071256. [PMID: 34203168 PMCID: PMC8310048 DOI: 10.3390/v13071256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 06/24/2021] [Indexed: 11/29/2022] Open
Affiliation(s)
- Anthony J Day
- Wellcome Trust Centre for Cell-Matrix Research and Lydia Becker Institute of Immunology and Inflammation, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester M13 9PT, UK
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14
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Armento A, Ueffing M, Clark SJ. The complement system in age-related macular degeneration. Cell Mol Life Sci 2021; 78:4487-4505. [PMID: 33751148 PMCID: PMC8195907 DOI: 10.1007/s00018-021-03796-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/05/2021] [Accepted: 02/19/2021] [Indexed: 12/13/2022]
Abstract
Age-related macular degeneration (AMD) is a chronic and progressive degenerative disease of the retina, which culminates in blindness and affects mainly the elderly population. AMD pathogenesis and pathophysiology are incredibly complex due to the structural and cellular complexity of the retina, and the variety of risk factors and molecular mechanisms that contribute to disease onset and progression. AMD is driven by a combination of genetic predisposition, natural ageing changes and lifestyle factors, such as smoking or nutritional intake. The mechanism by which these risk factors interact and converge towards AMD are not fully understood and therefore drug discovery is challenging, where no therapeutic attempt has been fully effective thus far. Genetic and molecular studies have identified the complement system as an important player in AMD. Indeed, many of the genetic risk variants cluster in genes of the alternative pathway of the complement system and complement activation products are elevated in AMD patients. Nevertheless, attempts in treating AMD via complement regulators have not yet been successful, suggesting a level of complexity that could not be predicted only from a genetic point of view. In this review, we will explore the role of complement system in AMD development and in the main molecular and cellular features of AMD, including complement activation itself, inflammation, ECM stability, energy metabolism and oxidative stress.
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Affiliation(s)
- Angela Armento
- Department for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Marius Ueffing
- Department for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany.
- Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, Tübingen, Germany.
| | - Simon J Clark
- Department for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany.
- Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, Tübingen, Germany.
- Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
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15
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Moore SR, Menon SS, Cortes C, Ferreira VP. Hijacking Factor H for Complement Immune Evasion. Front Immunol 2021; 12:602277. [PMID: 33717083 PMCID: PMC7947212 DOI: 10.3389/fimmu.2021.602277] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/15/2021] [Indexed: 12/15/2022] Open
Abstract
The complement system is an essential player in innate and adaptive immunity. It consists of three pathways (alternative, classical, and lectin) that initiate either spontaneously (alternative) or in response to danger (all pathways). Complement leads to numerous outcomes detrimental to invaders, including direct killing by formation of the pore-forming membrane attack complex, recruitment of immune cells to sites of invasion, facilitation of phagocytosis, and enhancement of cellular immune responses. Pathogens must overcome the complement system to survive in the host. A common strategy used by pathogens to evade complement is hijacking host complement regulators. Complement regulators prevent attack of host cells and include a collection of membrane-bound and fluid phase proteins. Factor H (FH), a fluid phase complement regulatory protein, controls the alternative pathway (AP) both in the fluid phase of the human body and on cell surfaces. In order to prevent complement activation and amplification on host cells and tissues, FH recognizes host cell-specific polyanionic markers in combination with complement C3 fragments. FH suppresses AP complement-mediated attack by accelerating decay of convertases and by helping to inactivate C3 fragments on host cells. Pathogens, most of which do not have polyanionic markers, are not recognized by FH. Numerous pathogens, including certain bacteria, viruses, protozoa, helminths, and fungi, can recruit FH to protect themselves against host-mediated complement attack, using either specific receptors and/or molecular mimicry to appear more like a host cell. This review will explore pathogen complement evasion mechanisms involving FH recruitment with an emphasis on: (a) characterizing the structural properties and expression patterns of pathogen FH binding proteins, as well as other strategies used by pathogens to capture FH; (b) classifying domains of FH important in pathogen interaction; and (c) discussing existing and potential treatment strategies that target FH interactions with pathogens. Overall, many pathogens use FH to avoid complement attack and appreciating the commonalities across these diverse microorganisms deepens the understanding of complement in microbiology.
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Affiliation(s)
- Sara R Moore
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Smrithi S Menon
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Claudio Cortes
- Department of Foundational Medical Sciences, Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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16
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Dopler A, Stibitzky S, Hevey R, Mannes M, Guariento M, Höchsmann B, Schrezenmeier H, Ricklin D, Schmidt CQ. Deregulation of Factor H by Factor H-Related Protein 1 Depends on Sialylation of Host Surfaces. Front Immunol 2021; 12:615748. [PMID: 33732239 PMCID: PMC7959842 DOI: 10.3389/fimmu.2021.615748] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/18/2021] [Indexed: 11/27/2022] Open
Abstract
To discriminate between self and non-self surfaces and facilitate immune surveillance, the complement system relies on the interplay between surface-directed activators and regulators. The dimeric modulator FHR-1 is hypothesized to competitively remove the complement regulator FH from surfaces that strongly fix opsonic C3b molecules—a process known as “deregulation.” The C-terminal regions of FH and FHR-1 provide the basis of this competition. They contain binding sites for C3b and host surface markers and are identical except for two substitutions: S1191L and V1197A (i.e., FH “SV”; FHR-1 “LA”). Intriguingly, an FHR-1 variant featuring the “SV” combination of FH predisposes to atypical hemolytic uremic syndrome (aHUS). The functional impact of these mutations on complement (de)regulation, and their pathophysiological consequences, have largely remained elusive. We have addressed these questions using recombinantly expressed wildtype, mutated, and truncated versions of FHR-1 and FH. The “SV” to “LA” substitutions did not affect glycosaminoglycan recognition and had only a small effect on C3b binding. In contrast, the two amino acids substantially affected the binding of FH and FHR-1 to α2,3-linked sialic acids as host surfaces markers, with the S-to-L substitution causing an almost complete loss of recognition. Even with sialic acid-binding constructs, notable deregulation was only detected on host and not foreign cells. The aHUS-associated “SV” mutation converts FHR-1 into a sialic acid binder which, supported by its dimeric nature, enables excessive FH deregulation and, thus, complement activation on host surfaces. While we also observed inhibitory activities of FHR-1 on C3 and C5 convertases, the high concentrations required render the physiological impact uncertain. In conclusion, the SV-to-LA substitution in the C-terminal regions of FH and FHR-1 diminishes its sialic acid-binding ability and results in an FHR-1 molecule that only moderately deregulates FH. Such FH deregulation by FHR-1 only occurs on host/host-like surfaces that recruit FH. Conversion of FHR-1 into a sialic acid binder potentiates the deregulatory capacity of FHR-1 and thus explains the pathophysiology of the aHUS-associated FHR-1 “SV” variant.
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Affiliation(s)
- Arthur Dopler
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Selina Stibitzky
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Rachel Hevey
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Marco Mannes
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Mara Guariento
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Britta Höchsmann
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service and University Hospital of Ulm, Ulm, Germany
| | - Hubert Schrezenmeier
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service and University Hospital of Ulm, Ulm, Germany
| | - Daniel Ricklin
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
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17
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Zouache MA, Bennion A, Hageman JL, Pappas C, Richards BT, Hageman GS. Macular retinal thickness differs markedly in age-related macular degeneration driven by risk polymorphisms on chromosomes 1 and 10. Sci Rep 2020; 10:21093. [PMID: 33273512 PMCID: PMC7713215 DOI: 10.1038/s41598-020-78059-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/19/2020] [Indexed: 12/11/2022] Open
Abstract
The two most common genetic contributors to age-related macular degeneration (AMD), a leading cause of irreversible vision loss worldwide, are variants associated with CFH-CFHR5 on chromosome 1 (Chr1) and ARMS2/HTRA1 on chromosome 10 (Chr10). We sought to determine if risk and protective variants associated with these two loci drive differences in macular retinal thickness prior and subsequent to the onset of clinically observable signs of AMD. We considered 299 individuals (547 eyes) homozygous for risk variants or haplotypes on Chr1 or Chr10 exclusively (Chr1-risk and Chr10-risk, respectively) or homozygous for a neutral haplotype (Chr1-neu), for the protective I62 tagged haplotype (Chr1-prot-I62) or for the protection conferring CFHR1/3 deletion haplotype (Chr1-prot-del) on Chr1 without any risk alleles on Chr10. Among eyes with no clinically observable signs of AMD, the deletion of CFHR1/3, which is strongly protective against this disease, is associated with significantly thicker retinas in the perifovea. When controlling for age, Chr10-risk eyes with early or intermediate AMD have thinner retinas as compared to eyes from the Chr1-risk group with similar disease severity. Our analysis indicates that this difference likely results from distinct biological and disease initiation and progression events associated with Chr1- and Chr10-directed AMD.
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Affiliation(s)
- Moussa A Zouache
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, 84132, UT, USA.
| | - Alex Bennion
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, 84132, UT, USA
| | - Jill L Hageman
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, 84132, UT, USA
| | - Christian Pappas
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, 84132, UT, USA
| | - Burt T Richards
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, 84132, UT, USA
| | - Gregory S Hageman
- Steele Center for Translational Medicine, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, 84132, UT, USA.
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18
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Stravalaci M, Davi F, Parente R, Gobbi M, Bottazzi B, Mantovani A, Day AJ, Clark SJ, Romano MR, Inforzato A. Control of Complement Activation by the Long Pentraxin PTX3: Implications in Age-Related Macular Degeneration. Front Pharmacol 2020; 11:591908. [PMID: 33324220 PMCID: PMC7725797 DOI: 10.3389/fphar.2020.591908] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/28/2020] [Indexed: 12/28/2022] Open
Abstract
Dysregulation of the complement system is central to age-related macular degeneration (AMD), the leading cause of blindness in the developed world. Most of the genetic variation associated with AMD resides in complement genes, with the greatest risk associated with polymorphisms in the complement factor H (CFH) gene; factor H (FH) is the major inhibitor of the alternative pathway (AP) of complement that specifically targets C3b and the AP C3 convertase. Long pentraxin 3 (PTX3) is a soluble pattern recognition molecule that has been proposed to inhibit AP activation via recruitment of FH. Although present in the human retina, if and how PTX3 plays a role in AMD is still unclear. In this work we demonstrated the presence of PTX3 in the human vitreous and studied the PTX3-FH-C3b crosstalk and its effects on complement activation in a model of retinal pigment epithelium (RPE). RPE cells cultured in inflammatory AMD-like conditions overexpressed the PTX3 protein, and up-regulated AP activating genes. PTX3 bound RPE cells in a physiological setting, however this interaction was reduced in inflammatory conditions, whereby PTX3 had no complement-inhibiting activity on inflamed RPE. However, on non-cellular surfaces, PTX3 formed a stable ternary complex with FH and C3b that acted as a “hot spot” for complement inhibition. Our findings suggest a protective role for PTX3 in response to complement dysregulation in AMD and point to a novel mechanism of complement regulation by this pentraxin with potential implications in pathology and pharmacology of AMD.
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Affiliation(s)
- Matteo Stravalaci
- Department of Biomedical Sciences, Humanitas University, Milan, Italy.,Humanitas Clinical and Research Center IRCCS, Milan, Italy
| | - Francesca Davi
- Humanitas Clinical and Research Center IRCCS, Milan, Italy
| | | | - Marco Gobbi
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | | | - Alberto Mantovani
- Department of Biomedical Sciences, Humanitas University, Milan, Italy.,Humanitas Clinical and Research Center IRCCS, Milan, Italy.,The William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Anthony J Day
- Wellcome Trust Centre for Cell-Matrix Research and Lydia Becker Institute of Immunology and Inflammation, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Simon J Clark
- Universitäts-Augenklinik Tübingen, Eberhard Karls University of Tübingen, Tübingen, Germany.,The Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Mario R Romano
- Department of Biomedical Sciences, Humanitas University, Milan, Italy.,Eye Center, Humanitas Gavazzeni-Castelli, Bergamo, Italy
| | - Antonio Inforzato
- Department of Biomedical Sciences, Humanitas University, Milan, Italy.,Humanitas Clinical and Research Center IRCCS, Milan, Italy
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19
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Mannes M, Dopler A, Huber-Lang M, Schmidt CQ. Tuning the Functionality by Splicing: Factor H and Its Alternative Splice Variant FHL-1 Share a Gene but Not All Functions. Front Immunol 2020; 11:596415. [PMID: 33178228 PMCID: PMC7593401 DOI: 10.3389/fimmu.2020.596415] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 09/23/2020] [Indexed: 12/15/2022] Open
Abstract
The alternative pathway regulator Factor H-like protein 1 (FHL-1) is composed of the first 7 N-terminal complement control protein domains of Factor H (FH) and protects host surfaces from uncontrolled complement attack. Although FHL-1 shares the N-terminal regulatory domains with FH, it was thought to be a weaker regulator. Recently, the regulatory activity of FHL-1 was shown to be comparable to FH. Nonetheless, the question remained whether FHL-1 is an indispensable, unique regulator. The discovery that FHL-1 is the predominant regulator on Bruch’s membrane, a critical site for the onset and progression of age-related-macular degeneration (AMD), showed that FHL-1 is essential for complement regulation. A common single nucleotide polymorphism in FH/FHL-1 that predisposes for AMD underlines the important role of FHL-1 in this context. Reports that some cancer tissues specifically upregulate FHL-1 expression, thereby evading immune surveillance, suggests a pronounced regulatory activity of the splice variant. Several microorganisms specifically recruit FHL-1 to evade complement attack. From a phylogenetic point of view, FHL-1 appears much later than other complement regulators, which could imply a specific role that is possibly not systemic but rather tissue specific. This review focuses on the current knowledge of FHL-1 and its physiological and pathophysiological roles.
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Affiliation(s)
- Marco Mannes
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Arthur Dopler
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
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20
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Principato S, Pizza M, Rappuoli R. Meningococcal factor H binding protein as immune evasion factor and vaccine antigen. FEBS Lett 2020; 594:2657-2669. [PMID: 32298465 DOI: 10.1002/1873-3468.13793] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 01/15/2023]
Abstract
Factor H binding protein (fHbp) is a key virulence factor of Neisseria meningitidis and a main component of the two licensed vaccines against serogroup B meningococcus (Bexsero and Trumenba). fHbp is a surface-exposed lipoprotein that enables the bacterium to survive in human blood by binding the human complement regulator factor H (fH). When used as vaccine, the protein induces antibodies with potent bactericidal activity. While the fHbp gene is present in the majority of N. meningitidis serogroup B isolates, the expression level varies up to 15 times between different strains and more than 700 different sequence variants have been described. Antigenically, the protein has been divided into three variants or two subfamilies. The 3D structure of fHbp alone, in combination with fH or in complex with bactericidal antibodies, has been key to understanding the molecular details of the protein. In this article, we will review the biochemical and immunological properties of fHbp, and its key role in meningococcal pathogenesis, complement regulation, and immune evasion.
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21
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A genome-wide association study identifies key modulators of complement factor H binding to malondialdehyde-epitopes. Proc Natl Acad Sci U S A 2020; 117:9942-9951. [PMID: 32321835 PMCID: PMC7211993 DOI: 10.1073/pnas.1913970117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Dysregulation of the alternative complement pathway due to impaired binding of complement factor H (CFH) to self-ligands or altered self-ligands (e.g. malondialdehyde [MDA]-modified molecules) involved in homeostasis can promote the development of complement-related diseases, such as age-related macular degeneration (AMD). We identified, in an unbiased GWAS approach, that common genetic variants within the CFH gene family (rs1061170 and the deletion of the complement factor H-related protein 1 and 3 genes [CFHR3 and CFHR1]) act as major modulators of CFH recruitment and its ability to regulate complement on MDA-epitopes. These findings demonstrate the importance of the genetic status within the CFH/CFHR3/CFHR1 locus in tissue homeostasis and provide a mechanistic explanation as to why deletion of CFHR3/CFHR1 is protective in AMD development. Genetic variants within complement factor H (CFH), a major alternative complement pathway regulator, are associated with the development of age-related macular degeneration (AMD) and other complementopathies. This is explained with the reduced binding of CFH or its splice variant factor H-like protein 1 (FHL-1) to self-ligands or altered self-ligands (e.g., malondialdehyde [MDA]-modified molecules) involved in homeostasis, thereby causing impaired complement regulation. Considering the critical role of CFH in inhibiting alternative pathway activation on MDA-modified surfaces, we performed an unbiased genome-wide search for genetic variants that modify the ability of plasma CFH to bind MDA in 1,830 individuals and characterized the mechanistic basis and the functional consequences of this. In a cohort of healthy individuals, we identified rs1061170 in CFH and the deletion of CFHR3 and CFHR1 as dominant genetic variants that modify CFH/FHL-1 binding to MDA. We further demonstrated that FHR1 and FHR3 compete with CFH for binding to MDA-epitopes and that FHR1 displays the highest affinity toward MDA-epitopes compared to CFH and FHR3. Moreover, FHR1 bound to MDA-rich areas on necrotic cells and prevented CFH from mediating its cofactor activity on MDA-modified surfaces, resulting in enhanced complement activation. These findings provide a mechanistic explanation as to why the deletion of CFHR3 and CFHR1 is protective in AMD and highlight the importance of genetic variants within the CFH/CFHR3/CFHR1 locus in the recognition of altered-self in tissue homeostasis.
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22
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Association of Complement Factor D and H Polymorphisms with Recurrent Pregnancy Loss. Int J Mol Sci 2019; 21:ijms21010017. [PMID: 31861421 PMCID: PMC6981708 DOI: 10.3390/ijms21010017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/17/2019] [Accepted: 12/17/2019] [Indexed: 01/27/2023] Open
Abstract
Recurrent pregnancy loss (RPL) is defined as two or more consecutive pregnancy losses prior to 20 weeks of gestation, and the incidence of RPL is estimated at 1% of all pregnancies. While the etiologies of RPL are diverse, immune function is considered to be an important cause of RPL. In particular, the complement system is essential for stable development of the placenta and fetus. Moreover, complement factor D (CFD) and complement factor H (CFH) are important regulators of the complement system and are associated with diseases, such as age-related macular degeneration. Therefore, we investigated whether polymorphisms of CFD and CFH are associated with RPL in 412 women with RPL and 384 control women. Genotyping of three polymorphisms (CFD rs2230216, CFH rs1065489, and CFH rs1061170) was performed by TaqMan probe real-time PCR and PCR-restriction fragment length polymorphism. Association of three polymorphisms with RPL was evaluated by statistical analysis. The GT/TC genotype combination of CFH rs1065489 G>T/CFH rs1061170 T>C was associated with a decreased risk of RPL occurrence compared with reference genotypes (adjusted odds ratio [AOR] = 0.439; 95% confidence interval [CI] = 0.238–0.810; p = 0.008), and this association remained significant after adjustment for multiple comparisons using false discovery rate (FDR) correction (p = 0.040). In addition, the CFH rs1065489G>T polymorphism is associated with homocysteine and prolactin level and CFH rs1061170 TC genotype is related to uric acid and triglycerides level in RPL patients. Therefore, those factors could be possible clinical risk factors in RPL patients.
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23
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Kumar A, Nada R, Ramachandran R, Rawat A, Tiewsoh K, Das R, Rayat CS, Gupta KL, Vasishta RK. Outcome of C3 glomerulopathy patients: largest single-centre experience from South Asia. J Nephrol 2019; 33:539-550. [PMID: 31820418 DOI: 10.1007/s40620-019-00672-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/11/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND C3 glomerulopathy (C3G) is related to dysfunction of alternative complement pathway (ACP) because of its hyperactivation. Triggering factors and genetic profile are likely to be different in developing countries as compared to the Western world. Data regarding C3G from South Asian is scanty. STUDY DESIGN In the present study, 115 patients of C3G from 2012 to 2017 were analyzed. Clinical details were reviewed; serological levels of C3, C4, complement factor H or B and autoantibody testing was done by nephelometry/ELISA. Limited genetics workup for CFH and CFHR5 genes was done. RESULTS The prevalence of C3G was 1.52%. There was no difference in demographic and histopathologic profiles of C3G patients. Majority of patients had low functional assay and C3 levels. C3 nephritic factor was present in 47.5% of DDD and 38.6% of C3GN. Autoantibodies to CFH were present more often in the patients of C3GN (29.5%) than DDD (12.5%). Autoantibodies to CFB were equally common in both groups. Past history of infections was present in one-third patients and monoclonal paraproteins were present only in two patients. No pathogenic variants were noted in CFH/CFHR5 gene. On follow-up (3.2 + 1.6 years), complete and partial remission was achieved in one-fourth patients and 26% had resistance disease. About 40% progressed to ESRD and 18 underwent renal transplantation of which nine had a post-transplant recurrence. CONCLUSIONS Indian cohort had some differences in the immunological and genetic profile when compared to the Western literature; most significant was the absence of monoclonal immunoglobulins as a trigger for C3G.
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Affiliation(s)
- Ashwani Kumar
- Department of Histopathology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Ritambhra Nada
- Department of Histopathology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India.
| | - Raja Ramachandran
- Department of Nephrology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Amit Rawat
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Karalanglin Tiewsoh
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Reena Das
- Department of Hematology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Charan Singh Rayat
- Department of Histopathology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Krishan Lal Gupta
- Department of Nephrology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Rakesh Kumar Vasishta
- Department of Histopathology, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012, India
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24
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Dopler A, Guntau L, Harder MJ, Palmer A, Höchsmann B, Schrezenmeier H, Simmet T, Huber-Lang M, Schmidt CQ. Self versus Nonself Discrimination by the Soluble Complement Regulators Factor H and FHL-1. THE JOURNAL OF IMMUNOLOGY 2019; 202:2082-2094. [DOI: 10.4049/jimmunol.1801545] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
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25
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Role of Gonococcal Neisserial Surface Protein A (NspA) in Serum Resistance and Comparison of Its Factor H Binding Properties with Those of Its Meningococcal Counterpart. Infect Immun 2019; 87:IAI.00658-18. [PMID: 30510105 DOI: 10.1128/iai.00658-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/25/2018] [Indexed: 01/15/2023] Open
Abstract
Neisseria gonorrhoeae, the causative agent of gonorrhea, has evolved several mechanisms to subvert complement, including binding of the complement inhibitor factor H (FH). We previously reported FH binding to N. gonorrhoeae independently of lipooligosaccharide (LOS) sialylation. Here we report that factor H-like protein 1 (FHL-1), which contains FH domains 1 through 7 and possesses complement-inhibitory activity, also binds to N. gonorrhoeae The ligand for both FH and FHL-1 was identified as neisserial surface protein A (NspA), which has previously been identified as a ligand for these molecules on Neisseria meningitidis As with N. meningitidis NspA (Nm-NspA), N. gonorrhoeae NspA (Ng-NspA) bound FH/FHL-1 through FH domains 6 and 7. Binding of FH/FHL-1 to NspA was human specific; the histidine (H) at position 337 of domain 6 contributed to human-specific FH binding to both Ng- and Nm-NspA. FH/FHL-1 bound Nm-NspA better than Ng-NspA; introducing Q at position 73 (loop 2, present in Ng-NspA) or replacing V and D at positions 112 and 113 in Nm-NspA loop 3 with A and H (Ng-NspA), respectively, reduced FH/FHL-1 binding. The converse Ng-NspA to Nm-NspA mutations increased FH/FHL-1 binding. Binding of FH/FHL-1 through domains 6 and 7 to N. gonorrhoeae increased with truncation of the heptose I (HepI) chain of LOS and decreased with LOS sialylation. Loss of NspA significantly decreased serum resistance of N. gonorrhoeae with either wild-type or truncated LOS. This report highlights the role for NspA in enabling N. gonorrhoeae to subvert complement despite LOS phase variation. Knowledge of FH-NspA interactions will inform the design of vaccines and immunotherapies against the global threat of multidrug-resistant gonorrhea.
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26
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Harrison RES, Morikis D. Molecular Mechanisms of Macular Degeneration Associated with the Complement Factor H Y402H Mutation. Biophys J 2018; 116:215-226. [PMID: 30616835 DOI: 10.1016/j.bpj.2018.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 10/24/2018] [Accepted: 12/07/2018] [Indexed: 01/02/2023] Open
Abstract
A single nucleotide polymorphism, tyrosine at position 402 to histidine (Y402H), within the gene encoding complement factor H (FH) predisposes individuals to acquiring age-related macular degeneration (AMD) after aging. This polymorphism occurs in short consensus repeat (SCR) 7 of FH and results in decreased binding affinity of SCR6-8 for heparin. As FH is responsible for regulating the complement system, decreased affinity for heparin results in decreased regulation on surfaces of self. To understand the involvement of the Y402H polymorphism in AMD, we leverage methods from bioinformatics and computational biophysics to quantify structural and dynamical differences between SCR7 isoforms that contribute to decreased pattern recognition in SCR7H402. Our data from molecular and Brownian dynamics simulations suggest a revised mechanism for decreased heparin binding. In this model, transient contacts not observed in structures for SCR7 are predicted to occur in molecular dynamics simulations between coevolved residues Y402 and I412, stabilizing SCR7Y402 in a conformation that promotes association with heparin. H402 in the risk isoform is less likely to form a contact with I412 and samples a larger conformational space than Y402. We observe energy minima for sidechains of Y402 and R404 from SCR7Y402 that are predicted to associate with heparin at a rate constant faster than energy minima for sidechains of H402 and R404 from SCR7H402. As both carbohydrate density and degree of sulfation decrease with age in Bruch's membrane of the macula, the decreased heparin recognition of SCR7H402 may contribute to the pathogenesis of AMD.
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Affiliation(s)
- Reed E S Harrison
- Department of Bioengineering, University of California, Riverside, Riverside, California
| | - Dimitrios Morikis
- Department of Bioengineering, University of California, Riverside, Riverside, California.
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27
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Osborne AJ, Nan R, Miller A, Bhatt JS, Gor J, Perkins SJ. Two distinct conformations of factor H regulate discrete complement-binding functions in the fluid phase and at cell surfaces. J Biol Chem 2018; 293:17166-17187. [PMID: 30217822 PMCID: PMC6222095 DOI: 10.1074/jbc.ra118.004767] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/10/2018] [Indexed: 11/06/2022] Open
Abstract
Factor H (FH) is the major regulator of C3b in the alternative pathway of the complement system in immunity. FH comprises 20 short complement regulator (SCR) domains, including eight glycans, and its Y402H polymorphism predisposes those who carry it to age-related macular degeneration. To better understand FH complement binding and self-association, we have studied the solution structures of both the His-402 and Tyr-402 FH allotypes. Analytical ultracentrifugation revealed that up to 12% of both FH allotypes self-associate, and this was confirmed by small-angle X-ray scattering (SAXS), MS, and surface plasmon resonance analyses. SAXS showed that monomeric FH has a radius of gyration (Rg ) of 7.2-7.8 nm and a length of 25 nm. Starting from known structures for the SCR domains and glycans, the SAXS data were fitted using Monte Carlo methods to determine atomistic structures of monomeric FH. The analysis of 29,715 physically realistic but randomized FH conformations resulted in 100 similar best-fit FH structures for each allotype. Two distinct molecular structures resulted that showed either an extended N-terminal domain arrangement with a folded-back C terminus or an extended C terminus and a folded-back N terminus. These two structures are the most accurate to date for glycosylated full-length FH. To clarify FH functional roles in host protection, crystal structures for the FH complexes with C3b and C3dg revealed that the extended N-terminal conformation accounted for C3b fluid-phase regulation, the extended C-terminal conformation accounted for C3d binding, and both conformations accounted for bivalent FH binding to glycosaminoglycans on the target cell surface.
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Affiliation(s)
- Amy J Osborne
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ruodan Nan
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ami Miller
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Jayesh S Bhatt
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Jayesh Gor
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Stephen J Perkins
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
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28
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Harris CL, Pouw RB, Kavanagh D, Sun R, Ricklin D. Developments in anti-complement therapy; from disease to clinical trial. Mol Immunol 2018; 102:89-119. [PMID: 30121124 DOI: 10.1016/j.molimm.2018.06.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 02/06/2023]
Abstract
The complement system is well known for its role in innate immunity and in maintenance of tissue homeostasis, providing a first line of defence against infection and playing a key role in flagging apoptotic cells and debris for disposal. Unfortunately complement also contributes to pathogenesis of a number of diseases; in some cases driving pathology, and in others amplifying or exacerbating the inflammatory and damaging impact of non-complement disease triggers. The role of complement in pathogenesis of an expanding number of diseases has driven industry and academia alike to develop an impressive arsenal of anti-complement drugs which target different proteins and functions of the complement cascade. Evidence from genetic and biochemical analyses, combined with improved identification of complement biomarkers and supportive data from sophisticated animal models of disease, has driven a drug development landscape in which the indications selected for clinical trial cluster in three 'target' tissues: the kidney, eye and vasculature. While the disease triggers may differ, complement activation and amplification is a common feature in many diseases which affect these three tissues. An abundance of drugs are in clinical development, some show favourable progression whereas others experience significant challenges. However, these hurdles in themselves drive an ever-evolving portfolio of 'next-generation' drugs with improved pharmacokinetic and pharmacodynamics properties. In this review we discuss the indications which are in the drug development 'spotlight' and review the relevant indication validation criteria. We present current progress in clinical trials, highlighting successes and difficulties, and look forward to approval of a wide selection of drugs for use in man which give clinicians choice in mechanistic target, modality and route of delivery.
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Affiliation(s)
- Claire L Harris
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK.
| | - Richard B Pouw
- Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056, Basel, Switzerland
| | - David Kavanagh
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK
| | - Ruyue Sun
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Daniel Ricklin
- Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056, Basel, Switzerland.
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29
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Geerlings MJ, Volokhina EB, de Jong EK, van de Kar N, Pauper M, Hoyng CB, van den Heuvel LP, den Hollander AI. Genotype-phenotype correlations of low-frequency variants in the complement system in renal disease and age-related macular degeneration. Clin Genet 2018; 94:330-338. [PMID: 29888403 PMCID: PMC6175426 DOI: 10.1111/cge.13392] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/24/2018] [Accepted: 06/03/2018] [Indexed: 12/28/2022]
Abstract
Genetic alterations in the complement system have been linked to a variety of diseases, including atypical hemolytic uremic syndrome (aHUS), C3 glomerulopathy (C3G), and age‐related macular degeneration (AMD). We performed sequence analysis of the complement genes complement factor H (CFH), complement factor I (CFI), and complement C3 (C3) in 866 aHUS/C3G and 697 AMD patients. In total, we identified 505 low‐frequency alleles, representing 121 unique variants, of which 51 are novel. CFH contained the largest number of unique low‐frequency variants (n = 64; 53%), followed by C3 (n = 32; 26%) and CFI (n = 25; 21%). A substantial number of variants were found in both patients groups (n = 48; 40%), while 41 (34%) variants were found only in aHUS/C3G and 32 (26%) variants were AMD specific. Genotype‐phenotype correlations between the disease groups identified a higher frequency of protein altering alleles in short consensus repeat 20 (SCR20) of factor H (FH), and in the serine protease domain of factor I (FI) in aHUS/C3G patients. In AMD, a higher frequency of protein‐altering alleles was observed in SCR3, SCR5, and SCR7 of FH, the SRCR domain of FI, and in the MG3 domain of C3. In conclusion, we observed a substantial overlap of variants between aHUS/C3G and AMD; however, there is a distinct clustering of variants within specific domains.
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Affiliation(s)
- M J Geerlings
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - E B Volokhina
- Radboud university medical center, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Department of Pediatric Nephrology, Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - E K de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - N van de Kar
- Radboud university medical center, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Department of Pediatric Nephrology, Nijmegen, The Netherlands
| | - M Pauper
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - C B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - L P van den Heuvel
- Radboud university medical center, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Department of Pediatric Nephrology, Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Pediatrics, Department of Growth and Regeneration, University Hospital Leuven, Leuven, Belgium
| | - A I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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30
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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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31
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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: 20] [Impact Index Per Article: 3.3] [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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32
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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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33
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Antonioli AH, White J, Crawford F, Renner B, Marchbank KJ, Hannan JP, Thurman JM, Marrack P, Holers VM. Modulation of the Alternative Pathway of Complement by Murine Factor H-Related Proteins. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:316-326. [PMID: 29187587 PMCID: PMC5736413 DOI: 10.4049/jimmunol.1602017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 10/27/2017] [Indexed: 01/21/2023]
Abstract
Factor H (FH) is a key alternative pathway regulator that controls complement activation both in the fluid phase and on specific cell surfaces, thus allowing the innate immune response to discriminate between self and foreign pathogens. However, the interrelationships between FH and a group of closely related molecules, designated the FH-related (FHR) proteins, are currently not well understood. Whereas some studies have suggested that human FHR proteins possess complement regulatory abilities, recent studies have shown that FHR proteins are potent deregulators. Furthermore, the roles of the FHR proteins have not been explored in any in vivo models of inflammatory disease. In this study, we report the cloning and expression of recombinant mouse FH and three FHR proteins (FHR proteins A-C). Results from functional assays show that FHR-A and FHR-B proteins antagonize the protective function of FH in sheep erythrocyte hemolytic assays and increase cell-surface C3b deposition on a mouse kidney proximal tubular cell line (TEC) and a human retinal pigment epithelial cell line (ARPE-19). We also report apparent KD values for the binding interaction of mouse C3d with mouse FH (3.85 μM), FHR-A (136 nM), FHR-B (546 nM), and FHR-C (1.04 μM), which directly correlate with results from functional assays. Collectively, our work suggests that similar to their human counterparts, a subset of mouse FHR proteins have an important modulatory role in complement activation. Further work is warranted to define the in vivo context-dependent roles of these proteins and determine whether FHR proteins are suitable therapeutic targets for the treatment of complement-driven diseases.
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Affiliation(s)
| | - Janice White
- Howard Hughes Medical Institute, Denver, CO 80206
| | | | - Brandon Renner
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045
| | - Kevin J Marchbank
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne NE2 4HH, United Kingdom
| | - Jonathan P Hannan
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045
| | - Joshua M Thurman
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045
| | - Philippa Marrack
- Howard Hughes Medical Institute, Denver, CO 80206
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206; and
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045
| | - V Michael Holers
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045;
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34
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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. [PMID: 27647805 DOI: 10.1002/pmic.201600237] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [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, USA
| | - Min Zhu
- National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | | | - Michelle Shardell
- National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | | | - 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, USA.,Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Jennifer E Van Eyk
- Advanced Clinical BioSystems Research Institute, The Heart Institute and, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Luigi Ferrucci
- National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Richard D Semba
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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THE PATHOPHYSIOLOGY OF GEOGRAPHIC ATROPHY SECONDARY TO AGE-RELATED MACULAR DEGENERATION AND THE COMPLEMENT PATHWAY AS A THERAPEUTIC TARGET. Retina 2017; 37:819-835. [PMID: 27902638 PMCID: PMC5424580 DOI: 10.1097/iae.0000000000001392] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Geographic atrophy is an advanced form of age-related macular degeneration that can significantly impact visual function, but has no approved treatment. This review focuses on the pathophysiology of geographic atrophy, particularly the role of complement cascade dysregulation and emerging therapies targeting the complement cascade. Purpose: Geographic atrophy (GA) is an advanced, vision-threatening form of age-related macular degeneration (AMD) affecting approximately five million individuals worldwide. To date, there are no approved therapeutics for GA treatment; however, several are in clinical trials. This review focuses on the pathophysiology of GA, particularly the role of complement cascade dysregulation and emerging therapies targeting the complement cascade. Methods: Primary literature search on PubMed for GA, complement cascade in age-related macular degeneration. ClinicalTrials.gov was searched for natural history studies in GA and clinical trials of drugs targeting the complement cascade for GA. Results: Cumulative damage to the retina by aging, environmental stress, and other factors triggers inflammation via multiple pathways, including the complement cascade. When regulatory components in these pathways are compromised, as with several GA-linked genetic risk factors in the complement cascade, chronic inflammation can ultimately lead to the retinal cell death characteristic of GA. Complement inhibition has been identified as a key candidate for therapeutic intervention, and drugs targeting the complement pathway are currently in clinical trials. Conclusion: The complement cascade is a strategic target for GA therapy. Further research, including on natural history and genetics, is crucial to expand the understanding of GA pathophysiology and identify effective therapeutic targets.
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Neisseria cinerea Expresses a Functional Factor H Binding Protein Which Is Recognized by Immune Responses Elicited by Meningococcal Vaccines. Infect Immun 2017; 85:IAI.00305-17. [PMID: 28739825 PMCID: PMC5607398 DOI: 10.1128/iai.00305-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/07/2017] [Indexed: 12/12/2022] Open
Abstract
Neisseria meningitidis is a major cause of bacterial meningitis and sepsis worldwide. Capsular polysaccharide vaccines are available against meningococcal serogroups A, C, W, and Y. More recently two protein-based vaccines, Bexsero and Trumenba, against meningococcal serogroup B strains have been licensed; both vaccines contain meningococcal factor H binding protein (fHbp). fHbp is a surface-exposed lipoprotein that binds the negative complement regulator complement factor H (CFH), thereby inhibiting the alternative pathway of complement activation. Recent analysis of available genomes has indicated that some commensal Neisseria species also contain genes that potentially encode fHbp, although the functions of these genes and how immunization with fHbp-containing vaccines could affect the commensal flora have yet to be established. Here, we show that the commensal species Neisseria cinerea expresses functional fHbp on its surface and that it is responsible for recruitment of CFH by the bacterium. N. cinerea fHbp binds CFH with affinity similar to that of meningococcal fHbp and promotes survival of N. cinerea in human serum. We examined the potential impact of fHbp-containing vaccines on N. cinerea We found that immunization with Bexsero elicits serum bactericidal activity against N. cinerea, which is primarily directed against fHbp. The shared function of fHbp in N. cinerea and N. meningitidis and cross-reactive responses elicited by Bexsero suggest that the introduction of fHbp-containing vaccines has the potential to affect carriage of N. cinerea and other commensal species.
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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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de Jorge EG, Yebenes H, Serna M, Tortajada A, Llorca O, de Córdoba SR. How novel structures inform understanding of complement function. Semin Immunopathol 2017; 40:3-14. [PMID: 28808775 DOI: 10.1007/s00281-017-0643-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/03/2017] [Indexed: 11/30/2022]
Abstract
During the last decade, the complement field has experienced outstanding advancements in the mechanistic understanding of how complement activators are recognized, what C3 activation means, how protein complexes like the C3 convertases and the membrane attack complex are assembled, and how positive and negative complement regulators perform their function. All of this has been made possible mostly because of the contributions of structural biology to the study of the complement components. The wealth of novel structural data has frequently provided support to previously held knowledge, but often has added alternative and unexpected insights into complement function. Here, we will review some of these findings focusing in the alternative and terminal complement pathways.
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Affiliation(s)
- Elena Goicoechea de Jorge
- Department of Microbiology I (Immunology), Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Hugo Yebenes
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Marina Serna
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Agustín Tortajada
- Department of Microbiology I (Immunology), Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Oscar Llorca
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.,Structural Biology Programme, CNIO, C/ Melchor Fernández Almagro 3, 28029, Madrid, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain. .,Ciber de Enfermedades Raras, Madrid, Spain.
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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: 131] [Impact Index Per Article: 18.7] [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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40
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Blaum BS. The lectin self of complement factor H. Curr Opin Struct Biol 2017; 44:111-118. [DOI: 10.1016/j.sbi.2017.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 01/08/2017] [Accepted: 01/12/2017] [Indexed: 01/15/2023]
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41
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Ram S, Shaughnessy J, de Oliveira RB, Lewis LA, Gulati S, Rice PA. Gonococcal lipooligosaccharide sialylation: virulence factor and target for novel immunotherapeutics. Pathog Dis 2017; 75:3777971. [PMID: 28460033 PMCID: PMC5449626 DOI: 10.1093/femspd/ftx049] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 04/26/2017] [Indexed: 12/13/2022] Open
Abstract
Gonorrhea has become resistant to most conventional antimicrobials used in clinical practice. The global spread of multidrug-resistant isolates of Neisseria gonorrhoeae could lead to an era of untreatable gonorrhea. New therapeutic modalities with novel mechanisms of action that do not lend themselves to the development of resistance are urgently needed. Gonococcal lipooligosaccharide (LOS) sialylation is critical for complement resistance and for establishing infection in humans and experimental mouse models. Here we describe two immunotherapeutic approaches that target LOS sialic acid: (i) a fusion protein that comprises the region in the complement inhibitor factor H (FH) that binds to sialylated gonococci and IgG Fc (FH/Fc fusion protein) and (ii) analogs of sialic acid that are incorporated into LOS but fail to protect the bacterium against killing. Both molecules showed efficacy in the mouse vaginal colonization model of gonorrhea and may represent promising immunotherapeutic approaches to target multidrug-resistant isolates. Disabling key gonococcal virulence mechanisms is an effective therapeutic strategy because the reduction of virulence is likely to be accompanied by a loss of fitness, rapid elimination by host immunity and consequently, decreased transmission.
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Affiliation(s)
- Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rosane B. de Oliveira
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lisa A. Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sunita Gulati
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Peter A. Rice
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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42
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Zhang Y, Wu M, Hang T, Wang C, Yang Y, Pan W, Zang J, Zhang M, Zhang X. Staphylococcus aureus SdrE captures complement factor H's C-terminus via a novel 'close, dock, lock and latch' mechanism for complement evasion. Biochem J 2017; 474:1619-1631. [PMID: 28258151 PMCID: PMC5415847 DOI: 10.1042/bcj20170085] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 12/30/2022]
Abstract
Complement factor H (CFH) is a soluble complement regulatory protein essential for the down-regulation of the alternative pathway on interaction with specific markers on the host cell surface. It recognizes the complement component 3b (C3b) and 3d (C3d) fragments in addition to self cell markers (i.e. glycosaminoglycans, sialic acid) to distinguish host cells that deserve protection from pathogens that should be eliminated. The Staphylococcus aureus surface protein serine-aspartate repeat protein E (SdrE) was previously reported to bind human CFH as an immune-evasion tactic. However, the molecular mechanism underlying SdrE-CFH-mediated immune evasion remains unknown. In the present study, we identified a novel region at CFH's C-terminus (CFH1206-1226), which binds SdrE N2 and N3 domains (SdrEN2N3) with high affinity, and determined the crystal structures of apo-SdrEN2N3 and the SdrEN2N3-CFH1206-1226 complex. Comparison of the structure of the CFH-SdrE complex with other CFH structures reveals that CFH's C-terminal tail flips from the main body to insert into the ligand-binding groove of SdrE. In addition, SdrEN2N3 adopts a 'close' state in the absence of CFH, which undergoes a large conformational change on CFH binding, suggesting a novel 'close, dock, lock and latch' (CDLL) mechanism for SdrE to recognize its ligand. Our findings imply that SdrE functions as a 'clamp' to capture CFH's C-terminal tail via a unique CDLL mechanism and sequesters CFH on the surface of S. aureus for complement evasion.
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Affiliation(s)
- Yingjie Zhang
- School of Life Science, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Minhao Wu
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Center for Excellence in Biomacromolecules, Collaborative Innovation Center of Chemistry for Life Sciences, and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Tianrong Hang
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Center for Excellence in Biomacromolecules, Collaborative Innovation Center of Chemistry for Life Sciences, and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Chengliang Wang
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Center for Excellence in Biomacromolecules, Collaborative Innovation Center of Chemistry for Life Sciences, and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Ye Yang
- School of Life Science, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Weimin Pan
- School of Life Science, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Jianye Zang
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Center for Excellence in Biomacromolecules, Collaborative Innovation Center of Chemistry for Life Sciences, and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Min Zhang
- School of Life Science, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Xuan Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, CAS Center for Excellence in Biomacromolecules, Collaborative Innovation Center of Chemistry for Life Sciences, and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, China
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43
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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: 122] [Impact Index Per Article: 15.3] [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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44
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Mulloy B, Hogwood J, Gray E, Lever R, Page CP. Pharmacology of Heparin and Related Drugs. Pharmacol Rev 2016; 68:76-141. [PMID: 26672027 DOI: 10.1124/pr.115.011247] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Heparin has been recognized as a valuable anticoagulant and antithrombotic for several decades and is still widely used in clinical practice for a variety of indications. The anticoagulant activity of heparin is mainly attributable to the action of a specific pentasaccharide sequence that acts in concert with antithrombin, a plasma coagulation factor inhibitor. This observation has led to the development of synthetic heparin mimetics for clinical use. However, it is increasingly recognized that heparin has many other pharmacological properties, including but not limited to antiviral, anti-inflammatory, and antimetastatic actions. Many of these activities are independent of its anticoagulant activity, although the mechanisms of these other activities are currently less well defined. Nonetheless, heparin is being exploited for clinical uses beyond anticoagulation and developed for a wide range of clinical disorders. This article provides a "state of the art" review of our current understanding of the pharmacology of heparin and related drugs and an overview of the status of development of such drugs.
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Affiliation(s)
- Barbara Mulloy
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - John Hogwood
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - Elaine Gray
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - Rebecca Lever
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - Clive P Page
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
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45
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Creating functional sophistication from simple protein building blocks, exemplified by factor H and the regulators of complement activation. Biochem Soc Trans 2016; 43:812-8. [PMID: 26517887 DOI: 10.1042/bst20150074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Complement control protein modules (CCPs) occur in numerous functionally diverse extracellular proteins. Also known as short consensus repeats (SCRs) or sushi domains each CCP contains approximately 60 amino acid residues, including four consensus cysteines participating in two disulfide bonds. Varying in length and sequence, CCPs adopt a β-sandwich type fold and have an overall prolate spheroidal shape with N- and C-termini lying close to opposite poles of the long axis. CCP-containing proteins are important as cytokine receptors and in neurotransmission, cell adhesion, blood clotting, extracellular matrix formation, haemoglobin metabolism and development, but CCPs are particularly well represented in the vertebrate complement system. For example, factor H (FH), a key soluble regulator of the alternative pathway of complement activation, is made up entirely from a chain of 20 CCPs joined by short linkers. Collectively, therefore, the 20 CCPs of FH must mediate all its functional capabilities. This is achieved via collaboration and division of labour among these modules. Structural studies have illuminated the dynamic architectures that allow FH and other CCP-rich proteins to perform their biological functions. These are largely the products of a highly varied set of intramolecular interactions between CCPs. The CCP can act as building block, spacer, highly versatile recognition site or dimerization mediator. Tandem CCPs may form composite binding sites or contribute to flexible, rigid or conformationally 'switchable' segments of the parent proteins.
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46
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Probing the solution structure of Factor H using hydroxyl radical protein footprinting and cross-linking. Biochem J 2016; 473:1805-19. [PMID: 27099340 DOI: 10.1042/bcj20160225] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 04/19/2016] [Indexed: 11/17/2022]
Abstract
The control protein Factor H (FH) is a crucial regulator of the innate immune complement system, where it is active on host cell membranes and in the fluid phase. Mutations impairing the binding capacity of FH lead to severe autoimmune diseases. Here, we studied the solution structure of full-length FH, in its free state and bound to the C3b complement protein. To do so, we used two powerful techniques, hydroxyl radical protein footprinting (HRPF) and chemical cross-linking coupled with mass spectrometry (MS), to probe the structural rearrangements and to identify protein interfaces. The footprint of C3b on the FH surface matches existing crystal structures of C3b complexed with the N- and C-terminal fragments of FH. In addition, we revealed the position of the central portion of FH in the protein complex. Moreover, cross-linking studies confirmed the involvement of the C-terminus in the dimerization of FH.
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Molins B, Fuentes-Prior P, Adán A, Antón R, Arostegui JI, Yagüe J, Dick AD. Complement factor H binding of monomeric C-reactive protein downregulates proinflammatory activity and is impaired with at risk polymorphic CFH variants. Sci Rep 2016; 6:22889. [PMID: 26961257 PMCID: PMC4785391 DOI: 10.1038/srep22889] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/23/2016] [Indexed: 11/30/2022] Open
Abstract
Inflammation and immune-mediated processes are pivotal to the pathogenic progression of age-related macular degeneration (AMD). Although plasma levels of C-reactive protein (CRP) have been shown to be associated with an increased risk for AMD, the pathophysiological importance of the prototypical acute-phase reactant in the etiology of the disease is unknown, and data regarding the exact role of CRP in ocular inflammation are limited. In this study, we provide mechanistic insight into how CRP contributes to the development of AMD. In particular, we show that monomeric CRP (mCRP) but not the pentameric form (pCRP) upregulates IL-8 and CCL2 levels in retinal pigment epithelial cells. Further, we show that complement factor H (FH) binds mCRP to dampen its proinflammatory activity. FH from AMD patients carrying the “risk” His402 polymorphism displays impaired binding to mCRP, and therefore proinflammatory effects of mCRP remain unrestrained.
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Affiliation(s)
- Blanca Molins
- Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, 08028 Barcelona, Spain
| | - Pablo Fuentes-Prior
- Molecular Bases of Disease, Biomedical Research Institute Sant Pau (IIB Sant Pau), 08025 Barcelona, Spain.,Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Spain
| | - Alfredo Adán
- Institut d'Investigacions Biomèdiques Agustí Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, 08028 Barcelona, Spain
| | - Rosa Antón
- Molecular Bases of Disease, Biomedical Research Institute Sant Pau (IIB Sant Pau), 08025 Barcelona, Spain
| | - Juan I Arostegui
- Department of Immunology-CDB, Hospital Clínic-IDIBAPS, 08028 Barcelona, Spain
| | - Jordi Yagüe
- Department of Immunology-CDB, Hospital Clínic-IDIBAPS, 08028 Barcelona, Spain
| | - Andrew D Dick
- Academic Unit of Ophthalmology, School of Clinical Sciences and School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TH, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital and University College London Institute of Ophthalmology, London, EC1V 2PD, UK
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48
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Renner B, Tong HH, Laskowski J, Jonscher K, Goetz L, Woolaver R, Hannan J, Li YX, Hourcade D, Pickering MC, Holers VM, Thurman JM. Annexin A2 Enhances Complement Activation by Inhibiting Factor H. THE JOURNAL OF IMMUNOLOGY 2016; 196:1355-65. [PMID: 26729803 DOI: 10.4049/jimmunol.1500793] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 11/27/2015] [Indexed: 12/31/2022]
Abstract
Factor H is a circulating protein that regulates activation of the alternative pathway (AP) of complement. Mutations and genetic variations of factor H are associated with several AP-mediated diseases, highlighting the critical role of factor H in AP regulation. AP-mediated inflammation is typically triggered by illness or tissue injury, however, and tissue injury can trigger AP activation in individuals with fully functional factor H. This suggests that factor H function is affected by local conditions within tissues. We hypothesized that inducible proteins impair the ability of factor H to locally control the AP, thereby increasing AP activation. We used purified murine factor H to immunoprecipitate binding partners from mouse kidneys. Using immunoaffinity liquid chromatography-mass spectrometry, we identified annexin A2 as a factor H binding partner. Further experiments showed that annexin A2 reduces the binding of factor H to cell surfaces. Recombinant annexin A2 impaired complement regulation by factor H and increased complement activation on renal cell surfaces in vitro and in vivo. In a murine model of acute pneumococcal otitis media, the administration of annexin A2 increased AP-mediated bacterial opsonization and clearance. In conclusion, the local production of annexin A2 within tissues suppresses regulation of the AP by factor H. Annexin A2 can contribute to AP-mediated tissue inflammation by locally impairing factor H function, but it can also improve complement-mediated bacterial clearance.
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Affiliation(s)
- Brandon Renner
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Hua Hua Tong
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210
| | - Jennifer Laskowski
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Karen Jonscher
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Lindsey Goetz
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Rachel Woolaver
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Jonathan Hannan
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Yong Xing Li
- Department of Otolaryngology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210
| | - Dennis Hourcade
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110; and
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, South Kensington Campus, Imperial College, London SW7 2AZ, United Kingdom
| | - V Michael Holers
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Joshua M Thurman
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045;
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49
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Bajic G, Degn SE, Thiel S, Andersen GR. Complement activation, regulation, and molecular basis for complement-related diseases. EMBO J 2015; 34:2735-57. [PMID: 26489954 DOI: 10.15252/embj.201591881] [Citation(s) in RCA: 243] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/28/2015] [Indexed: 01/13/2023] Open
Abstract
The complement system is an essential element of the innate immune response that becomes activated upon recognition of molecular patterns associated with microorganisms, abnormal host cells, and modified molecules in the extracellular environment. The resulting proteolytic cascade tags the complement activator for elimination and elicits a pro-inflammatory response leading to recruitment and activation of immune cells from both the innate and adaptive branches of the immune system. Through these activities, complement functions in the first line of defense against pathogens but also contributes significantly to the maintenance of homeostasis and prevention of autoimmunity. Activation of complement and the subsequent biological responses occur primarily in the extracellular environment. However, recent studies have demonstrated autocrine signaling by complement activation in intracellular vesicles, while the presence of a cytoplasmic receptor serves to detect complement-opsonized intracellular pathogens. Furthermore, breakthroughs in both functional and structural studies now make it possible to describe many of the intricate molecular mechanisms underlying complement activation and the subsequent downstream events, as well as its cross talk with, for example, signaling pathways, the coagulation system, and adaptive immunity. We present an integrated and updated view of complement based on structural and functional data and describe the new roles attributed to complement. Finally, we discuss how the structural and mechanistic understanding of the complement system rationalizes the genetic defects conferring uncontrolled activation or other undesirable effects of complement.
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Affiliation(s)
- Goran Bajic
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Søren E Degn
- Department of Biomedicine, Aarhus University, Aarhus, Denmark Program in Cellular and Molecular Medicine, Children's Hospital, Boston, MA, USA
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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50
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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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