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Sonnentag SJ, Dopler A, Kleiner K, Garg BK, Mannes M, Späth N, Akilah A, Höchsmann B, Schrezenmeier H, Anliker M, Boyanapalli R, Huber-Lang M, Schmidt CQ. Triple-fusion protein (TriFu): A potent, targeted, enzyme-like inhibitor of all three complement activation pathways. J Biol Chem 2024; 300:105784. [PMID: 38401844 PMCID: PMC11065761 DOI: 10.1016/j.jbc.2024.105784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 02/05/2024] [Accepted: 02/20/2024] [Indexed: 02/26/2024] Open
Abstract
The introduction of a therapeutic anti-C5 antibody into clinical practice in 2007 inspired a surge into the development of complement-targeted therapies. This has led to the recent approval of a C3 inhibitory peptide, an antibody directed against C1s and a full pipeline of several complement inhibitors in preclinical and clinical development. However, no inhibitor is available that efficiently inhibits all three complement initiation pathways and targets host cell surface markers as well as complement opsonins. To overcome this, we engineered a novel fusion protein combining selected domains of the three natural complement regulatory proteins decay accelerating factor, factor H and complement receptor 1. Such a triple fusion complement inhibitor (TriFu) was recombinantly expressed and purified alongside multiple variants and its building blocks. We analyzed these proteins for ligand binding affinity and decay acceleration activity by surface plasmon resonance. Additionally, we tested complement inhibition in several in vitro/ex vivo assays using standard classical and alternative pathway restricted hemolysis assays next to hemolysis assays with paroxysmal nocturnal hemoglobinuria erythrocytes. A novel in vitro model of the alternative pathway disease C3 glomerulopathy was established to evaluate the potential of the inhibitors to stop C3 deposition on endothelial cells. Next to the novel engineered triple fusion variants which inactivate complement convertases in an enzyme-like fashion, stoichiometric complement inhibitors targeting C3, C5, factor B, and factor D were tested as comparators. The triple fusion approach yielded a potent complement inhibitor that efficiently inhibits all three complement initiation pathways while targeting to surface markers.
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Affiliation(s)
- Sophia J Sonnentag
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Centre, Ulm, Germany
| | - Arthur Dopler
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Centre, Ulm, Germany
| | - Katharina Kleiner
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Centre, Ulm, Germany
| | | | - Marco Mannes
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Nadja Späth
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Centre, Ulm, Germany
| | - Amira Akilah
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Centre, 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, Baden-Württemberg-Hessen 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, Baden-Württemberg-Hessen and University Hospital of Ulm, Ulm, Germany
| | - Markus Anliker
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany; Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service, Baden-Württemberg-Hessen and University Hospital of Ulm, Ulm, Germany
| | | | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Christoph Q Schmidt
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Centre, Ulm, Germany; Institute of Pharmacy, Biochemical Pharmacy Group, Martin Luther University Halle-Wittenberg, Halle, Germany.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Namburi P, Khateb S, Meyer S, Bentovim T, Ratnapriya R, Khramushin A, Swaroop A, Schueler-Furman O, Banin E, Sharon D. A unique PRDM13-associated variant in a Georgian Jewish family with probable North Carolina macular dystrophy and the possible contribution of a unique CFH variant. Mol Vis 2020; 26:299-310. [PMID: 32476814 PMCID: PMC7245606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 04/14/2020] [Indexed: 12/04/2022] Open
Abstract
Purpose North Carolina macular dystrophy (NCMD) is an autosomal dominant maculopathy that is considered a non-progressive developmental disorder with variable expressivity. Our study aimed to clinically and genetically characterize macular dystrophy in a family (MOL1154) consisting of six affected subjects with a highly variable maculopathy phenotype in which no correlation between age and severity exists. Methods Clinical characterization included visual acuity testing and electroretinography. Genetic analysis included Sanger sequencing and whole exome sequencing (WES). Results WES analysis performed on DNA samples from two individuals revealed a heterozygous deletion of six nucleotides [c.2247_2252del; p.(Leu750_Lys751del)] in the CFH gene. Co-segregation analysis revealed that five of the six NCMD affected subjects carried this deletion, while one individual who had a relatively mild phenotype compatible with dry age-related macular degeneration (AMD) did not carry it. We subsequently analyzed the upstream region of PRDM13 that has previously been reported to be associated with NCMD and identified a unique heterozygous transversion (chr6:100040974A>C) located within the previously described suspected control region in all six affected individuals. This transversion is likely to cause NCMD. Conclusions NCMD has a wide spectrum of clinical phenotypes that can overlap with AMD, making it challenging to correctly diagnose affected individuals and family members. The DNA sequence variant we found in the CFH gene of some of the affected family members may suggest some role as a modifier gene. However, this variant still does not explain the huge phenotypic variability of NCMD and needs to be studied in other and larger populations.
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Affiliation(s)
- Prasanthi Namburi
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Samer Khateb
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Segev Meyer
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Tom Bentovim
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Rinki Ratnapriya
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Alisa Khramushin
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Ora Schueler-Furman
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University Jerusalem, Jerusalem, Israel
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Macleod OJS, Bart JM, MacGregor P, Peacock L, Savill NJ, Hester S, Ravel S, Sunter JD, Trevor C, Rust S, Vaughan TJ, Minter R, Mohammed S, Gibson W, Taylor MC, Higgins MK, Carrington M. A receptor for the complement regulator factor H increases transmission of trypanosomes to tsetse flies. Nat Commun 2020; 11:1326. [PMID: 32165615 PMCID: PMC7067766 DOI: 10.1038/s41467-020-15125-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 02/15/2020] [Indexed: 11/09/2022] Open
Abstract
Persistent pathogens have evolved to avoid elimination by the mammalian immune system including mechanisms to evade complement. Infections with African trypanosomes can persist for years and cause human and animal disease throughout sub-Saharan Africa. It is not known how trypanosomes limit the action of the alternative complement pathway. Here we identify an African trypanosome receptor for mammalian factor H, a negative regulator of the alternative pathway. Structural studies show how the receptor binds ligand, leaving inhibitory domains of factor H free to inactivate complement C3b deposited on the trypanosome surface. Receptor expression is highest in developmental stages transmitted to the tsetse fly vector and those exposed to blood meals in the tsetse gut. Receptor gene deletion reduced tsetse infection, identifying this receptor as a virulence factor for transmission. This demonstrates how a pathogen evolved a molecular mechanism to increase transmission to an insect vector by exploitation of a mammalian complement regulator.
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Affiliation(s)
- Olivia J S Macleod
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Jean-Mathieu Bart
- Intertryp, IRD, Cirad, University of Montpellier, Montpellier, France
| | - Paula MacGregor
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK
| | - Nicholas J Savill
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, UK
| | - Svenja Hester
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Sophie Ravel
- Intertryp, IRD, Cirad, University of Montpellier, Montpellier, France
| | - Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK
| | - Camilla Trevor
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Steven Rust
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Tristan J Vaughan
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Ralph Minter
- Department of Antibody Discovery and Protein Engineering, AstraZeneca R&D, Granta Park, Cambridge, CB21 6GH, UK
| | - Shabaz Mohammed
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK
| | - Martin C Taylor
- Faculty of Infectious and Tropical diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK.
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Zipfel PF, Wiech T, Stea ED, Skerka C. CFHR Gene Variations Provide Insights in the Pathogenesis of the Kidney Diseases Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy. J Am Soc Nephrol 2020; 31:241-256. [PMID: 31980588 PMCID: PMC7003313 DOI: 10.1681/asn.2019050515] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sequence and copy number variations in the human CFHR-Factor H gene cluster comprising the complement genes CFHR1, CFHR2, CFHR3, CFHR4, CFHR5, and Factor H are linked to the human kidney diseases atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy. Distinct genetic and chromosomal alterations, deletions, or duplications generate hybrid or mutant CFHR genes, as well as hybrid CFHR-Factor H genes, and alter the FHR and Factor H plasma repertoire. A clear association between the genetic modifications and the pathologic outcome is emerging: CFHR1, CFHR3, and Factor H gene alterations combined with intact CFHR2, CFHR4, and CFHR5 genes are reported in atypical hemolytic uremic syndrome. But alterations in each of the five CFHR genes in the context of an intact Factor H gene are described in C3 glomerulopathy. These genetic modifications influence complement function and the interplay of the five FHR proteins with each other and with Factor H. Understanding how mutant or hybrid FHR proteins, Factor H::FHR hybrid proteins, and altered Factor H, FHR plasma profiles cause pathology is of high interest for diagnosis and therapy.
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Affiliation(s)
- Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany;
- Institute of Microbiology, Friedrich-Schiller-University, Jena, Germany; and
| | - Thorsten Wiech
- Section of Nephropathology, Institute of Pathology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Emma D Stea
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
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6
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Akhter MS, Singh S, Yadegari H, Ivaskevicius V, Oldenburg J, Biswas A. Exploring the structural similarity yet functional distinction between coagulation factor XIII-B and complement factor H sushi domains. J Thromb Thrombolysis 2019; 48:95-102. [PMID: 30915671 DOI: 10.1007/s11239-019-01841-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Coagulation factor XIII (FXIII) covalently crosslinks pre-formed fibrin clots preventing their premature fibrinolysis. In plasma, FXIII circulates as a zymogenic heterotetramer composed of catalytic FXIII-A subunits, and carrier/regulatory FXIII-B subunits. FXIII-A is a well characterized component of this complex, and has been associated with several pleiotropic roles outside coagulation as well. In comparison only protective/regulatory roles towards the FXIII-A subunit have been identified for FXIII-B. Strong homology between FXIII-B and complement regulator Complement factor H suggests a putative role of FXIII-B in complement activation. In the current study we have analyzed the similarities and yet functional divergence of these two proteins using in silico sequence alignment and structural analysis. We have evaluated complement activation post reconstitution of FXIII components into FXIII deficient and CFH deficient plasma. We have also transiently expressed FXIII-B in SH-SY5Y cell lines and evaluated its effect on the endogenous complement activation. Our investigations show no effect of FXIII-B subunit on the rate of complement activation. Therefore we conclude that at a physiological level, FXIII-B subunit plays no role in the complement system, although a vestigial function in altered pathological states might still exist.
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Affiliation(s)
- Mohammad Suhail Akhter
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53127, Bonn, Germany
- College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Sneha Singh
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53127, Bonn, Germany
| | - Hamideh Yadegari
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53127, Bonn, Germany
| | - Vytautas Ivaskevicius
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53127, Bonn, Germany
| | - Johannes Oldenburg
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53127, Bonn, Germany
| | - Arijit Biswas
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53127, Bonn, Germany.
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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Kim S, Park E, Min SI, Yi NJ, Ha J, Ha IS, Cheong HI, Kang HG. Kidney Transplantation in Patients with Atypical Hemolytic Uremic Syndrome due to Complement Factor H Deficiency: Impact of Liver Transplantation. J Korean Med Sci 2018; 33:e4. [PMID: 29215813 PMCID: PMC5729639 DOI: 10.3346/jkms.2018.33.e4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/01/2017] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Atypical hemolytic uremic syndrome (aHUS) is a rare disease that is often associated with genetic defects. Mutations of complement factor H (CFH) are the most common genetic defects that cause aHUS and often result in end-stage renal disease. Since CFH is mainly produced in the liver, liver transplantation (LT) has been performed in patients with defective CFH. METHODS The clinical courses of four kidney allograft recipients who lost their native kidney functions due to aHUS associated with a CFH mutation were reviewed. RESULTS Subject A underwent kidney transplantation (KT) twice, aHUS recurred and the allograft kidney failed within a few years. Subject B received a KT and soon experienced a recurrence of aHUS coinciding with infection. Her allograft kidney function has worsened, and she remains on plasma infusion therapy. Subject C underwent LT followed by KT. She is doing well without plasma infusion therapy after combined LT-KT for 3 years. Subject D received KT following LT and is now recurrence-free from aHUS. CONCLUSION In patients with aHUS associated with a CFH mutation, KT without LT was complicated with a recurrence of aHUS, which might lead to allograft loss. Conversely, LT was successful in preventing the recurrence of aHUS and thus might be another option for a recurrence-free life for aHUS patients associated with CFH mutation.
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Affiliation(s)
- Sejin Kim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Eujin Park
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
- Research Coordination Center for Rare Disease, Seoul National University Hospital, Seoul, Korea
| | - Sang Il Min
- Department of Surgery, Seoul National University College of Medicine, Seoul, Korea
| | - Nam Joon Yi
- Department of Surgery, Seoul National University College of Medicine, Seoul, Korea
| | - Jongwon Ha
- Department of Surgery, Seoul National University College of Medicine, Seoul, Korea
| | - Il Soo Ha
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Hae Il Cheong
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
- Research Coordination Center for Rare Disease, Seoul National University Hospital, Seoul, Korea
- Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
- Research Coordination Center for Rare Disease, Seoul National University Hospital, Seoul, Korea.
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9
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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10
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Luo M, Zhang X, Zhang S, Zhang H, Yang W, Zhu Z, Chen K, Bai L, Wei J, Huang A, Wang D. Crystal Structure of an Invasivity-Associated Domain of SdrE in S. aureus. PLoS One 2017; 12:e0168814. [PMID: 28125581 PMCID: PMC5268492 DOI: 10.1371/journal.pone.0168814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/06/2016] [Indexed: 12/04/2022] Open
Abstract
The surface protein SdrE, a microbial surface components recognizing adhesive matrix molecule (MSCRAMM) family protein expressed on the surface of Staphylococcus aureus (S. aureus), can recognize human complement regulator Factor H and C4BP, thus making it a potentially promising vaccine candidate. In this study, SdrE278-591 was found to directly affect S. aureus host cell invasion. Additionally, the crystal structure of SdrE278-591 at a resolution of 1.25 Å was established, with the three-dimensional structure revealing N2-N3 domains which fold in a manner similar to an IgG fold. Furthermore, a putative ligand binding site located at a conserved charged groove formed by the interface between N2 and N3 domains was identified, with β2 suspected to occupy the ligand recognizing site and undergo a structural rearrangement to allow ligand binding. Overall, these findings have further contributed to the understanding of SdrE as a key factor for S. aureus invasivity and will enable a better understanding of bacterial infection processes.
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Affiliation(s)
- Miao Luo
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
- Department of Laboratory Medicine, People’s Hospital of YuBei District, YuBei District, Chongqing, People’s Republic of China
| | - Xiang Zhang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
| | - Shaocheng Zhang
- Department of Laboratory Medicine, Chongqing Medical University, YixueYuanlu-1, Chongqing, People’s Republic of China
| | - Hongpeng Zhang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
| | - Wei Yang
- Department of Laboratory Medicine, Hospital of Zhejiang, Xihu District, Hangzhou, People’s Republic of China
| | - Zhongliang Zhu
- School of Life Science, the University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Ke Chen
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
| | - Lei Bai
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
| | - Jie Wei
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
| | - Ailong Huang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
| | - Deqiang Wang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, PR China
- Department of Laboratory Medicine, Chongqing Medical University, YixueYuanlu-1, Chongqing, People’s Republic of China
- * E-mail:
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11
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Bushey RT, Moody MA, Nicely NL, Haynes BF, Alam SM, Keir ST, Bentley RC, Roy Choudhury K, Gottlin EB, Campa MJ, Liao HX, Patz EF. A Therapeutic Antibody for Cancer, Derived from Single Human B Cells. Cell Rep 2016; 15:1505-1513. [PMID: 27160908 DOI: 10.1016/j.celrep.2016.04.038] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/17/2016] [Accepted: 04/05/2016] [Indexed: 12/21/2022] Open
Abstract
Some patients with cancer never develop metastasis, and their host response might provide cues for innovative treatment strategies. We previously reported an association between autoantibodies against complement factor H (CFH) and early-stage lung cancer. CFH prevents complement-mediated cytotoxicity (CDC) by inhibiting formation of cell-lytic membrane attack complexes on self-surfaces. In an effort to translate these findings into a biologic therapy for cancer, we isolated and expressed DNA sequences encoding high-affinity human CFH antibodies directly from single, sorted B cells obtained from patients with the antibody. The co-crystal structure of a CFH antibody-target complex shows a conformational change in the target relative to the native structure. This recombinant CFH antibody causes complement activation and release of anaphylatoxins, promotes CDC of tumor cell lines, and inhibits tumor growth in vivo. The isolation of anti-tumor antibodies derived from single human B cells represents an alternative paradigm in antibody drug discovery.
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MESH Headings
- Alanine/genetics
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/therapeutic use
- Autoantibodies/immunology
- B-Lymphocytes/immunology
- Cell Line, Tumor
- Cell Proliferation
- Cloning, Molecular
- Complement Factor H/chemistry
- Complement Factor H/immunology
- Complement System Proteins/immunology
- Crystallography, X-Ray
- Cytotoxicity, Immunologic
- Disease Models, Animal
- Epitopes/immunology
- Gene Rearrangement
- Humans
- Lung Neoplasms/drug therapy
- Lung Neoplasms/pathology
- Mice, Nude
- Models, Molecular
- Mutagenesis/genetics
- Peptides/chemistry
- Peptides/immunology
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Affiliation(s)
- Ryan T Bushey
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - M Anthony Moody
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA; Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
| | - Nathan L Nicely
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - S Munir Alam
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Stephen T Keir
- Department of Neurosurgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Rex C Bentley
- Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA
| | - Kingshuk Roy Choudhury
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27710, USA
| | - Elizabeth B Gottlin
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael J Campa
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Hua-Xin Liao
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
| | - Edward F Patz
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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12
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Dyer A, Brown G, Stejskal L, Laity PR, Bingham RJ. The Borrelia afzelii outer membrane protein BAPKO_0422 binds human factor-H and is predicted to form a membrane-spanning β-barrel. Biosci Rep 2015; 35:e00240. [PMID: 26181365 PMCID: PMC4613713 DOI: 10.1042/bsr20150095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 06/23/2015] [Accepted: 07/06/2015] [Indexed: 12/11/2022] Open
Abstract
The deep evolutionary history of the Spirochetes places their branch point early in the evolution of the diderms, before the divergence of the present day Proteobacteria. As a spirochete, the morphology of the Borrelia cell envelope shares characteristics of both Gram-positive and Gram-negative bacteria. A thin layer of peptidoglycan, tightly associated with the cytoplasmic membrane, is surrounded by a more labile outer membrane (OM). This OM is rich in lipoproteins but with few known integral membrane proteins. The outer membrane protein A (OmpA) domain is an eight-stranded membrane-spanning β-barrel, highly conserved among the Proteobacteria but so far unknown in the Spirochetes. In the present work, we describe the identification of four novel OmpA-like β-barrels from Borrelia afzelii, the most common cause of erythema migrans (EM) rash in Europe. Structural characterization of one these proteins (BAPKO_0422) by SAXS and CD indicate a compact globular structure rich in β-strand consistent with a monomeric β-barrel. Ab initio molecular envelopes calculated from the scattering profile are consistent with homology models and demonstrate that BAPKO_0422 adopts a peanut shape with dimensions 25×45 Å (1 Å=0.1 nm). Deviations from the standard C-terminal signature sequence are apparent; in particular the C-terminal phenylalanine residue commonly found in Proteobacterial OM proteins is replaced by isoleucine/leucine or asparagine. BAPKO_0422 is demonstrated to bind human factor H (fH) and therefore may contribute to immune evasion by inhibition of the complement response. Encoded by chromosomal genes, these proteins are highly conserved between Borrelia subspecies and may be of diagnostic or therapeutic value.
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Affiliation(s)
- Adam Dyer
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Gemma Brown
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Lenka Stejskal
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Peter R Laity
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K. Present Address: Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, University of Sheffield, Sheffield S1 3JD, U.K
| | - Richard J Bingham
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
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13
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Cugno M, Gualtierotti R, Possenti I, Testa S, Tel F, Griffini S, Grovetti E, Tedeschi S, Salardi S, Cresseri D, Messa P, Ardissino G. Complement functional tests for monitoring eculizumab treatment in patients with atypical hemolytic uremic syndrome. J Thromb Haemost 2014; 12:1440-8. [PMID: 24853860 DOI: 10.1111/jth.12615] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 05/14/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy characterized by hemolysis, platelet consumption, and renal injury. Eculizumab, a mAb that blocks complement activity, has been successfully used in aHUS. OBJECTIVES To optimize eculizumab therapy in aHUS patients by monitoring complement functional tests and markers of disease activity. PATIENTS/METHODS We studied 18 patients with aHUS (10 males; eight females; age range, 2-40 years) treated with eculizumab to induce and/or maintain disease remission. Patients were followed up for a cumulative observation period of 160 months, during which blood samples were obtained at various time intervals to measure complement activity (Wieslab for the classical, alternative and mannose-binding lectin complement pathways) and the parameters of disease activity (haptoglobin and lactate dehydrogenase serum levels, and platelet count). The intravenous eculizumab doses of 12-33 mg kg(-1) were initially administered every week, with the interval between doses being gradually extended to 2 weeks, 3 weeks and 4 weeks on the basis of strict laboratory and clinical control. RESULTS Complement activity was normal before eculizumab treatment, regardless of the state of the disease (activity or remission). It was completely suppressed 1 week, 2 weeks and 3 weeks after the last eculizumab infusion (mean values ± standard deviation: 1% ± 1% to 3% ± 5% for both the classical and alternative pathways; P = 0.0001 vs. baseline), and partially suppressed after 4 weeks (22% ± 26% and 16% ± 27%; P = 0.0001 vs. baseline). The increase in the time interval between eculizumab infusions did not change disease activity markers. CONCLUSIONS Monitoring complement tests can allow a safe reduction in the frequency of eculizumab administration in aHUS while keeping the disease in remission.
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Affiliation(s)
- M Cugno
- Medicina Interna, Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
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14
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Yu BB, Moffatt BE, Fedorova M, Villiers CGS, Arnold JN, Du E, Swinkels A, Li MC, Ryan A, Sim RB. Purification, quantification, and functional analysis of Complement Factor H. Methods Mol Biol 2014; 1100:207-23. [PMID: 24218262 DOI: 10.1007/978-1-62703-724-2_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Complement Factor H (FH) is an abundant, non-enzymic plasma/serum glycoprotein, which has a major role in regulating activation of the complement system. It can be purified from human plasma/serum by affinity chromatography, using a monoclonal anti-FH antibody as ligand. Other affinity chromatography ligands, including cardiolipin and trinitrophenyl-bovine serum albumin (TNP-BSA), can be used to purify human FH and also FH from a wide range of vertebrates, including mammals, birds, bony fish. Human FH protein concentration can be quantified by sandwich ELISA. The activity of FH is generally measured by assays which detect the cleavage, by complement factor I, of the complement protein C3b to form iC3b. Cleavage occurs only in the presence of a cofactor, and FH is one of a small number of cofactors for this reaction.
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Affiliation(s)
- Bing-Bin Yu
- Department of Biochemistry, University of Oxford, Oxford, UK
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15
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Nilsson OR, Lannergård J, Morgan BP, Lindahl G, Gustafsson MCU. Affinity purification of human factor H on polypeptides derived from streptococcal m protein: enrichment of the Y402 variant. PLoS One 2013; 8:e81303. [PMID: 24278416 PMCID: PMC3836803 DOI: 10.1371/journal.pone.0081303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/10/2013] [Indexed: 11/29/2022] Open
Abstract
Recent studies indicate that defective activity of complement factor H (FH) is associated with several human diseases, suggesting that pure FH may be used for therapy. Here, we describe a simple method to isolate human FH, based on the specific interaction between FH and the hypervariable region (HVR) of certain Streptococcus pyogenes M proteins. Special interest was focused on the FH polymorphism Y402H, which is associated with the common eye disease age-related macular degeneration (AMD) and has also been implicated in the binding to M protein. Using a fusion protein containing two copies of the M5-HVR, we found that the Y402 and H402 variants of FH could be efficiently purified by single-step affinity chromatography from human serum containing the corresponding protein. Different M proteins vary in their binding properties, and the M6 and M5 proteins, but not the M18 protein, showed selective binding of the FH Y402 variant. Accordingly, chromatography on a fusion protein derived from the M6-HVR allowed enrichment of the Y402 protein from serum containing both variants. Thus, the exquisite binding specificity of a bacterial protein can be exploited to develop a simple and robust procedure to purify FH and to enrich for the FH variant that protects against AMD.
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Affiliation(s)
- O. Rickard Nilsson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Department of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jonas Lannergård
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - B. Paul Morgan
- Institute of Infection & Immunity, Cardiff University, Cardiff, United Kingdom
| | - Gunnar Lindahl
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Department of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark
| | - Mattias C. U. Gustafsson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Department of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark
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16
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Caesar JJE, Wallich R, Kraiczy P, Zipfel PF, Lea SM. Further structural insights into the binding of complement factor H by complement regulator-acquiring surface protein 1 (CspA) of Borrelia burgdorferi. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:629-33. [PMID: 23722839 PMCID: PMC3668580 DOI: 10.1107/s1744309113012748] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/09/2013] [Indexed: 06/02/2023]
Abstract
Borrelia burgdorferi has evolved many mechanisms of evading the different immune systems across its range of reservoir hosts, including the capture and presentation of host complement regulators factor H and factor H-like protein-1 (FHL-1). Acquisition is mediated by a family of complement regulator-acquiring surface proteins (CRASPs), of which the atomic structure of CspA (BbCRASP-1) is known and shows the formation of a homodimeric species which is required for binding. Mutagenesis studies have mapped a putative factor H binding site to a cleft between the two subunits. Presented here is a new atomic structure of CspA which shows a degree of flexibility between the subunits which may be critical for factor H scavenging by increasing access to the binding interface and allows the possibility that the assembly can clamp around the bound complement regulators.
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Affiliation(s)
- Joseph J. E. Caesar
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Reinhard Wallich
- Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, 69120 Heidelberg, Germany
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, Frankfurt University Hospital, Paul-Ehrlich-Strasse 40, 60596 Frankfurt, Germany
| | - Peter F. Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Products Research and Infection Biology, Beutenbergstrasse 11a, 07745 Jena, Germany
- Friedrich Schiller University of Jena, 07737 Jena, Germany
| | - Susan M. Lea
- Oxford Martin School of Vaccine Design, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, England
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17
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Meri T, Amdahl H, Lehtinen MJ, Hyvärinen S, McDowell JV, Bhattacharjee A, Meri S, Marconi R, Goldman A, Jokiranta TS. Microbes bind complement inhibitor factor H via a common site. PLoS Pathog 2013; 9:e1003308. [PMID: 23637600 PMCID: PMC3630169 DOI: 10.1371/journal.ppat.1003308] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Accepted: 03/02/2013] [Indexed: 11/18/2022] Open
Abstract
To cause infections microbes need to evade host defense systems, one of these being the evolutionarily old and important arm of innate immunity, the alternative pathway of complement. It can attack all kinds of targets and is tightly controlled in plasma and on host cells by plasma complement regulator factor H (FH). FH binds simultaneously to host cell surface structures such as heparin or glycosaminoglycans via domain 20 and to the main complement opsonin C3b via domain 19. Many pathogenic microbes protect themselves from complement by recruiting host FH. We analyzed how and why different microbes bind FH via domains 19–20 (FH19-20). We used a selection of FH19-20 point mutants to reveal the binding sites of several microbial proteins and whole microbes (Haemophilus influenzae, Bordetella pertussis, Pseudomonas aeruginosa, Streptococcus pneumonia, Candida albicans, Borrelia burgdorferi, and Borrelia hermsii). We show that all studied microbes use the same binding region located on one side of domain 20. Binding of FH to the microbial proteins was inhibited with heparin showing that the common microbial binding site overlaps with the heparin site needed for efficient binding of FH to host cells. Surprisingly, the microbial proteins enhanced binding of FH19-20 to C3b and down-regulation of complement activation. We show that this is caused by formation of a tripartite complex between the microbial protein, FH, and C3b. In this study we reveal that seven microbes representing different phyla utilize a common binding site on the domain 20 of FH for complement evasion. Binding via this site not only mimics the glycosaminoglycans of the host cells, but also enhances function of FH on the microbial surfaces via the novel mechanism of tripartite complex formation. This is a unique example of convergent evolution resulting in enhanced immune evasion of important pathogens via utilization of a “superevasion site.” Complement is an important arm of innate immunity. Activation of this plasma protein cascade leads to opsonization of targets for phagocytosis, direct lysis of Gram-negative bacteria, and enhancement of the inflammatory and acquired immune responses. No specific signal is needed for activation of the alternative pathway of complement, leading to its activation on all unprotected surfaces. Pathogenic microbes need to evade this pathway, and several species are known to recruit host complement inhibitor factor H (FH) to prevent the activation. FH is important for protection of host cells, too, as defects in FH lead to a severe autoreactive disease, atypical hemolytic uremic syndrome. We have now identified at the molecular level a common mechanism by which seven different microbes, Haemophilus influenzae, Bordetella pertussis, Pseudomonas aeruginosa, Streptococcus pneumoniae, Candida albicans, Borrelia burgdorferi and B. hermsii, recruit FH. All microbes bind FH via a common site on domain 20, which facilitates formation of a tripartite complex between the microbial protein, the main complement opsonin C3b, and FH. We show that, by utilizing the common microbial binding site on FH20, microbes can inhibit complement more efficiently. This detailed knowledge on mechanism of complement evasion can be used in developing novel antimicrobial chemotherapy.
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Affiliation(s)
- T Meri
- Haartman Institute, Department of Bacteriology and Immunology and Immunobiology Research Program, University of Helsinki, Helsinki, Finland.
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18
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Makou E, Mertens HD, Maciejewski M, Soares DC, Matis I, Schmidt CQ, Herbert AP, Svergun DI, Barlow PN. Solution structure of CCP modules 10-12 illuminates functional architecture of the complement regulator, factor H. J Mol Biol 2012; 424:295-312. [PMID: 23017427 PMCID: PMC4068365 DOI: 10.1016/j.jmb.2012.09.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 09/17/2012] [Accepted: 09/18/2012] [Indexed: 01/08/2023]
Abstract
The 155-kDa plasma glycoprotein factor H (FH), which consists of 20 complement control protein (CCP) modules, protects self-tissue but not foreign organisms from damage by the complement cascade. Protection is achieved by selective engagement of FH, via CCPs 1-4, CCPs 6-8 and CCPs 19-20, with polyanion-rich host surfaces that bear covalently attached, activation-specific, fragments of complement component C3. The role of intervening CCPs 9-18 in this process is obscured by lack of structural knowledge. We have concatenated new high-resolution solution structures of overlapping recombinant CCP pairs, 10-11 and 11-12, to form a three-dimensional structure of CCPs 10-12 and validated it by small-angle X-ray scattering of the recombinant triple-module fragment. Superimposing CCP 12 of this 10-12 structure with CCP 12 from the previously solved CCP 12-13 structure yielded an S-shaped structure for CCPs 10-13 in which modules are tilted by 80-110° with respect to immediate neighbors, but the bend between CCPs 10 and 11 is counter to the arc traced by CCPs 11-13. Including this four-CCP structure in interpretation of scattering data for the longer recombinant segments, CCPs 10-15 and 8-15, implied flexible attachment of CCPs 8 and 9 to CCP 10 but compact and intimate arrangements of CCP 14 with CCPs 12, 13 and 15. Taken together with difficulties in recombinant production of module pairs 13-14 and 14-15, the aberrant structure of CCP 13 and the variability of 13-14 linker sequences among orthologues, a structural dependency of CCP 14 on its neighbors is suggested; this has implications for the FH mechanism.
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Key Words
- ccp, complement control protein
- cr1, complement receptor type 1
- daf, decay accelerating factor
- fh, factor h
- eom, ensemble optimization method
- hsqc, heteronuclear single quantum coherence
- mcp, membrane cofactor protein
- noe, nuclear overhauser enhancement
- saxs, small-angle x-ray scattering
- tocsy, total correlated spectroscopy
- protein nmr
- protein domains
- complement system
- small-angle x-ray scattering
- regulators of complement activation
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Affiliation(s)
- Elisavet Makou
- Schools of Chemistry and Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
| | - Haydyn D.T. Mertens
- European Molecular Biology Laboratory Hamburg Outstation, c/o Deutsches Elektronen‐Synchrotron, Notkestrasse 85, 22603 Hamburg, Germany
| | - Mateusz Maciejewski
- Schools of Chemistry and Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
| | - Dinesh C. Soares
- Medical Genetics Section, Molecular Medicine Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Ilias Matis
- Schools of Chemistry and Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
| | - Christoph Q. Schmidt
- Schools of Chemistry and Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
| | - Andrew P. Herbert
- Schools of Chemistry and Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory Hamburg Outstation, c/o Deutsches Elektronen‐Synchrotron, Notkestrasse 85, 22603 Hamburg, Germany
| | - Paul N. Barlow
- Schools of Chemistry and Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
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19
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Pechtl IC, Neely RK, Dryden DTF, Jones AC, Barlow PN. Use of time-resolved FRET to validate crystal structure of complement regulatory complex between C3b and factor H (N terminus). Protein Sci 2012; 20:2102-12. [PMID: 21936007 DOI: 10.1002/pro.738] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Structural knowledge of interactions amongst the ~ 40 proteins of the human complement system, which is central to immune surveillance and homeostasis, is expanding due primarily to X-ray diffraction of co-crystallized proteins. Orthogonal evidence, in solution, for the physiological relevance of such co-crystal structures is valuable since intermolecular affinities are generally weak-to-medium and inter-domain mobility may be important. In this current work, Förster resonance energy transfer (FRET) was used to investigate the 10 μM K(D) (210 kD) complex between the N-terminal region of the soluble complement regulator, factor H (FH1-4), and the key activation-specific complement fragment, C3b. Using site-directed mutagenesis, seven cysteines were introduced individually at potentially informative positions within the four CCP modules comprising FH1-4, then used for fluorophore attachment. C3b possesses a thioester domain featuring an internal cycloglutamyl cysteine thioester; upon hydrolysis this yields a free thiol (Cys988) that was also fluorescently tagged. Labeled proteins were functionally active as cofactors for cleavage of C3b to iC3b except for FH1-4(Q40C) where conjugation with the fluorophore likely abrogated interaction with the protease, factor I. Time-resolved FRET measurements were undertaken to explore interactions between FH1-4 and C3b in fluid phase and under near-physiological conditions. These experiments confirmed that, as in the cocrystal structure, FH1-4 binds to C3b with CCP module 1 furthest from, and CCP module 4 closest to, the thioester domain, placing subsequent modules of FH near to any surface to which C3b is attached. The data do not rule out flexibility of the thioester domain relative to the remainder of the complex.
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Affiliation(s)
- Isabell C Pechtl
- EaStCHEM School of Chemistry and Collaborative Optical Spectroscopy, Micromanipulation and Imaging Centre (COSMIC), University of Edinburgh, Edinburgh, United Kingdom
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20
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Morgan HP, Mertens HDT, Guariento M, Schmidt CQ, Soares DC, Svergun DI, Herbert AP, Barlow PN, Hannan JP. Structural analysis of the C-terminal region (modules 18-20) of complement regulator factor H (FH). PLoS One 2012; 7:e32187. [PMID: 22389686 PMCID: PMC3289644 DOI: 10.1371/journal.pone.0032187] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 01/23/2012] [Indexed: 11/19/2022] Open
Abstract
Factor H (FH) is a soluble regulator of the human complement system affording protection to host tissues. It selectively inhibits amplification of C3b, the activation-specific fragment of the abundant complement component C3, in fluid phase and on self-surfaces and accelerates the decay of the alternative pathway C3 convertase, C3bBb. We have determined the crystal structure of the three carboxyl-terminal complement control protein (CCP) modules of FH (FH18-20) that bind to C3b, and which additionally recognize polyanionic markers specific to self-surfaces. These CCPs harbour nearly 30 disease-linked missense mutations. We have also deployed small-angle X-ray scattering (SAXS) to investigate FH18-20 flexibility in solution using FH18-20 and FH19-20 constructs. In the crystal lattice FH18-20 adopts a "J"-shape: A ~122-degree tilt between the structurally highly similar modules 18 and 19 precedes an extended, linear arrangement of modules 19 and 20 as observed in previously determined structures of these two modules alone. However, under solution conditions FH18-20 adopts multiple conformations mediated by flexibility between CCPs 18 and 19. We also pinpoint the locations of disease-associated missense mutations on the module 18 surface and discuss our data in the context of the C3b:FH interaction.
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Affiliation(s)
- Hugh P. Morgan
- Institute of Structural and Molecular Biology, School of Biological Sciences, King's Buildings, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Mara Guariento
- Edinburgh Biomolecular NMR Unit, EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Christoph Q. Schmidt
- Edinburgh Biomolecular NMR Unit, EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Dinesh C. Soares
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, The University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, Hamburg, Germany
| | - Andrew P. Herbert
- Edinburgh Biomolecular NMR Unit, EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Paul N. Barlow
- Edinburgh Biomolecular NMR Unit, EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Jonathan P. Hannan
- Institute of Structural and Molecular Biology, School of Biological Sciences, King's Buildings, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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21
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Büttner-Mainik A, Parsons J, Jérôme H, Hartmann A, Lamer S, Schaaf A, Schlosser A, Zipfel PF, Reski R, Decker EL. Production of biologically active recombinant human factor H in Physcomitrella. Plant Biotechnol J 2011; 9:373-83. [PMID: 20723134 DOI: 10.1111/j.1467-7652.2010.00552.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The human complement regulatory serum protein factor H (FH) is a promising future biopharmaceutical. Defects in the gene encoding FH are associated with human diseases like severe kidney and retinal disorders in the form of atypical haemolytic uremic syndrome (aHUS), membranoproliferative glomerulonephritis II (MPGN II) or age-related macular degeneration (AMD). There is a current need to apply intact full-length FH for the therapy of patients with congenital or acquired defects of this protein. Application of purified or recombinant FH (rFH) to these patients is an important and promising approach for the treatment of these diseases. However, neither protein purified from plasma of healthy individuals nor recombinant protein is currently available on the market. Here, we report the first stable expression of the full-length human FH cDNA and the subsequent production of this glycoprotein in a plant system. The moss Physcomitrella patens perfectly suits the requirements for the production of complex biopharmaceuticals as this eukaryotic system not only offers an outstanding genetical accessibility, but moreover, proteins can be produced safely in scalable photobioreactors without the need for animal-derived medium compounds. Transgenic moss lines were created, which express the human FH cDNA and target the recombinant protein to the culture supernatant via a moss-derived secretion signal. Correct processing of the signal peptide and integrity of the moss-produced rFH were verified via peptide mapping by mass spectrometry. Ultimately, we show that the rFH displays complement regulatory activity comparable to FH purified from plasma.
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22
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Perkins SJ, Nan R, Okemefuna AI, Li K, Khan S, Miller A. Multiple interactions of complement Factor H with its ligands in solution: a progress report. Adv Exp Med Biol 2011; 703:25-47. [PMID: 20711705 DOI: 10.1007/978-1-4419-5635-4_3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Factor H (FH) is the major regulator of the central complement protein C3b in the alternative pathway of complement activation, and is comprised of 20 SCR domains. A FH Tyr402His polymorphism in SCR-7 is associated with age-related macular degeneration (AMD) and leads to deposition of complement in drusen. The unravelling of how FH interacts with five major physiological and patho-physiological ligands is complicated by the weak nature of these interactions, coupled with the multivalency of FH. Using multiple biophysical methods, we summarise our recent results for these five FH ligands: (1) FH by itself shows a folded-back SCR domain structure in solution, and self-associates in a manner dependent on electrostatic forces. (2) FH activity is inhibited by zinc, which causes FH to aggregate. The onset of FH-zinc aggregation for zinc concentrations above 20 muM appears to be enhanced with the His402 allotype, and may be relevant to AMD. (3) The FH and C-reactive protein (CRP) interaction has been controversial; however our new work resolves earlier discrepancies. The FH-CRP interaction is only observed when native CRP is at high acute-phase concentration levels, and CRP binds weakly to the His402 FH allotype to suggest a molecular mechanism that leads to AMD. (4) Heparin is an analogue of the polyanionic host cell surface, and FH forms higher oligomers with larger heparin fragments, suggesting a mechanism for more effective FH regulation. (5) The interaction of C3b with FH also depends on buffer, and FH forms multimers with the C3d fragment of C3b. This FH-C3d interaction at high FH concentration may also facilitate complement regulation. Overall, our results to date suggest that the FH interactions involving zinc and native CRP have the closest relevance for explaining the onset of AMD.
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Affiliation(s)
- Stephen J Perkins
- Department of Structural and Molecular Biology, University College London, London, UK.
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23
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Donoso LA, Vrabec T, Kuivaniemi H. The role of complement Factor H in age-related macular degeneration: a review. Surv Ophthalmol 2010; 55:227-46. [PMID: 20385334 DOI: 10.1016/j.survophthal.2009.11.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2009] [Revised: 10/20/2009] [Accepted: 11/03/2009] [Indexed: 11/19/2022]
Abstract
Factor H is a 155kDa sialic acid containing glycoprotein that plays an integral role in the regulation of the complement-mediated immune system that is involved in microbial defense, immune complex processing, and programmed cell death. These events take place primarily in fluid phase and on the cell surface and are particularly important in the context of distinguishing self from non-self. Activation of the complement system occurs within seconds and results in a proteolytic cascade eventually forming the membrane attack complex leading to cell lysis. Factor H protects host cells from injury resulting from unrestrained complement activation. Mutations and SNPs (single nucleotide polymorphisms) in Factor H have been implicated in a variety of human conditions including age-related macular degeneration (AMD), atypical hemolytic uremic syndrome, and membranoproliferative glomuleronephritis type II or dense deposit disease. It should not be surprising that these seemingly unrelated diseases involving mutations in Factor H may share common features. Because the immune process involves, in part, an inflammatory response and common or similar surface antigens, it is also not unexpected to observe features of inflammation, including deposition of bioactive complement fragments such as C3a and C5a, a cellular influx of immune related cells such as lymphocytes, and the potential for multiple organ involvement. We review recent developments in molecular genetics; SNPs, including Y402H; the three-dimensional structure; and mass spectroscopy of Factor H as it relates to the pathogenesis of eye disease. In addition, we discuss the concepts of molecular mimicry, sequestered or hidden antigens, and antigenic cross reactivity, and propose that AMD should not simply be considered to be an eye disease, but rather a systemic vascular disease where the eye has the ability to self regulate a local immune response. Identification of the initial event or inciting antigen has yet to be determined and will significantly advance the understanding of the pathogenesis of AMD.
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Affiliation(s)
- Larry A Donoso
- The Philadelphia Retina Endowment Fund, The Eye Research Institute, Philadelphia, PA, USA.
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24
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Okemefuna AI, Nan R, Miller A, Gor J, Perkins SJ. Complement factor H binds at two independent sites to C-reactive protein in acute phase concentrations. J Biol Chem 2010; 285:1053-65. [PMID: 19850925 PMCID: PMC2801232 DOI: 10.1074/jbc.m109.044529] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 10/13/2009] [Indexed: 01/10/2023] Open
Abstract
Factor H (FH) regulates the activation of C3b in the alternative complement pathway, both in serum and at host cell surfaces. It is composed of 20 short complement regulator (SCR) domains. The Y402H polymorphism in FH is a risk factor for age-related macular degeneration. C-reactive protein (CRP) is an acute phase protein that binds Ca(2+). We established the FH-CRP interaction using improved analytical ultracentrifugation (AUC), surface plasmon resonance (SPR), and synchrotron x-ray scattering methods. Physiological FH and CRP concentrations were used in 137 mM NaCl and 2 mM Ca(2+), in which the occurrence of denatured CRP was avoided. In solution, AUC revealed FH-CRP binding. The FH-CRP interaction inhibited the formation of higher FH oligomers, indicating that CRP blocked FH dimerization sites at both SCR-6/8 and SCR-16/20. SPR confirmed the FH-CRP interaction and its NaCl concentration dependence upon using either immobilized FH or CRP. The SCR-1/5 fragment of FH did not bind to CRP. In order of increasing affinity, SCR-16/20, SCR-6/8 (His-402), and SCR-6/8 (Tyr-402) fragments bound to CRP. X-ray scattering showed that FH became more compact when binding to CRP, which is consistent with CRP binding at two different FH sites. We concluded that FH and CRP bind at elevated acute phase concentrations of CRP in physiological buffer. The SCR-16/20 site is novel and indicates the importance of the FH-CRP interaction for both age-related macular degeneration and atypical hemolytic uremic syndrome.
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Affiliation(s)
- Azubuike I. Okemefuna
- 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 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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25
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Wu J, Wu YQ, Ricklin D, Janssen BJC, Lambris JD, Gros P. Structure of complement fragment C3b-factor H and implications for host protection by complement regulators. Nat Immunol 2009; 10:728-33. [PMID: 19503104 PMCID: PMC2713992 DOI: 10.1038/ni.1755] [Citation(s) in RCA: 262] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 05/14/2009] [Indexed: 01/28/2023]
Abstract
Factor H (FH) is an abundant regulator of complement activation and protects host cells from self-attack by complement. Here we provide insight into the regulatory activity of FH by solving the crystal structure of the first four domains of FH in complex with its target, complement fragment C3b. FH interacted with multiple domains of C3b, covering a large, extended surface area. The structure indicated that FH destabilizes the C3 convertase by competition and electrostatic repulsion and that FH enables proteolytic degradation of C3b by providing a binding platform for protease factor I while stabilizing the overall domain arrangement of C3b. Our results offer general models for complement regulation and provide structural explanations for disease-related mutations in the genes encoding both FH and C3b.
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Affiliation(s)
- Jin Wu
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
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26
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Fritzinger DC, Hew BE, Thorne M, Pangburn MK, Janssen BJC, Gros P, Vogel CW. Functional characterization of human C3/cobra venom factor hybrid proteins for therapeutic complement depletion. Dev Comp Immunol 2009; 33:105-116. [PMID: 18760301 DOI: 10.1016/j.dci.2008.07.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 05/26/2023]
Abstract
Cobra venom factor (CVF) is a structural and functional analog of complement C3 isolated from cobra venom. Both CVF and C3b can bind factor B and subsequently form the bimolecular C3/C5 convertases CVF,Bb or C3b,Bb, respectively. The two homologous enzymes exhibit several differences of which the difference in physico-chemical stability is most important, allowing continuous activation of C3 and C5 by CVF,Bb, leading to serum complement depletion. Here we describe the detailed functional properties of two hybrid proteins in which the 113 or 315 C-terminal residues of C3 were replaced with corresponding CVF sequences. Both hybrid proteins formed stable convertases that exhibited C3-cleaving activity, although at different rates. Neither convertase cleaved C5. Both convertases showed partial resistance to inactivation by factors H and I, allowing them to deplete complement in human serum. These data demonstrate that functionally important structural differences between CVF and C3 are located in the very C-terminal region of both homologous proteins, and that small substitutions in human C3 with homologous CVF sequence result in C3 derivatives with CVF-like functions. Such hybrid proteins are important tools to study the structure/function relationships in both C3 and CVF, and these "humanized CVF" proteins may become reagents for therapeutic complement depletion.
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Affiliation(s)
- David C Fritzinger
- Cancer Research Center of Hawaii, University of Hawaii at Manoa, 1236 Lauhala Street, Honolulu, HI 96813, USA.
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27
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Haupt K, Reuter M, van den Elsen J, Burman J, Hälbich S, Richter J, Skerka C, Zipfel PF. The Staphylococcus aureus protein Sbi acts as a complement inhibitor and forms a tripartite complex with host complement Factor H and C3b. PLoS Pathog 2008; 4:e1000250. [PMID: 19112495 PMCID: PMC2602735 DOI: 10.1371/journal.ppat.1000250] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Accepted: 12/01/2008] [Indexed: 12/15/2022] Open
Abstract
The Gram-positive bacterium Staphylococcus aureus, similar to other pathogens, binds human complement regulators Factor H and Factor H related protein 1 (FHR-1) from human serum. Here we identify the secreted protein Sbi (Staphylococcus aureus binder of IgG) as a ligand that interacts with Factor H by a—to our knowledge—new type of interaction. Factor H binds to Sbi in combination with C3b or C3d, and forms tripartite Sbi∶C3∶Factor H complexes. Apparently, the type of C3 influences the stability of the complex; surface plasmon resonance studies revealed a higher stability of C3d complexed to Sbi, as compared to C3b or C3. As part of this tripartite complex, Factor H is functionally active and displays complement regulatory activity. Sbi, by recruiting Factor H and C3b, acts as a potent complement inhibitor, and inhibits alternative pathway-mediated lyses of rabbit erythrocytes by human serum and sera of other species. Thus, Sbi is a multifunctional bacterial protein, which binds host complement components Factor H and C3 as well as IgG and β2-glycoprotein I and interferes with innate immune recognition. Staphylococcus aureus is a Gram-positive bacterium that can live as a commensal but can also cause severe life threatening infections in humans. Upon infection the bacterium is attacked by the host immune system, and in particular by the complement system which forms the immediate, first defence line of innate immunity. In order to survive, S. aureus has developed multiple evasion strategies and uses several virulence factors to evade and inactivate the host complement attack. Here we show that this pathogen binds the host complement regulators Factor H from human serum with the secreted and surface exposed Sbi protein, by a—to our knowledge—new type of interaction. Factor H binds to Sbi in combination with another host complement protein C3, C3b or C3d, and forms tripartite Sbi∶C3∶Factor H complexes. As part of this tripartite complex, Factor H is functionally active and inhibits further complement activation. Sbi, by recruiting Factor H and C3b, acts as a potent complement inhibitor, and inhibits alternative pathway-mediated lyses of rabbit erythrocytes by human serum and sera of different species. Thus, Sbi is a multifunctional bacterial protein, which binds host complement components Factor H and C3 as well as IgG and β2-glycoprotein I and interferes with innate immune recognition.
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Affiliation(s)
- Katrin Haupt
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Michael Reuter
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Jean van den Elsen
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Julia Burman
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Steffi Hälbich
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Julia Richter
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Peter F. Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
- Friedrich Schiller University, Jena, Germany
- * E-mail:
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28
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Siegel C, Schreiber J, Haupt K, Skerka C, Brade V, Simon MM, Stevenson B, Wallich R, Zipfel PF, Kraiczy P. Deciphering the ligand-binding sites in the Borrelia burgdorferi complement regulator-acquiring surface protein 2 required for interactions with the human immune regulators factor H and factor H-like protein 1. J Biol Chem 2008; 283:34855-63. [PMID: 18824548 PMCID: PMC2596382 DOI: 10.1074/jbc.m805844200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 09/12/2008] [Indexed: 11/06/2022] Open
Abstract
Borrelia burgdorferi, the etiologic agent of Lyme disease, employs sophisticated means to evade killing by its mammalian hosts. One important immune escape mechanism is the inhibition of complement activation mediated by interactions of the host-derived immune regulators factor H (CFH) and factor H-like protein 1 (CFHL1) with borrelial complement regulator-acquiring surface proteins (BbCRASPs). BbCRASP-2 is a distinctive CFH- and CFHL1-binding protein that is produced by serum-resistant B. burgdorferi strains. Here we show that binding of CFH by BbCRASP-2 is due to electrostatic as well as hydrophobic forces. In addition, 14 individual amino acid residues of BbCRASP-2 were identified as being involved in CFH and CFHL1 binding. Alanine substitutions of most of those residues significantly inhibited binding of CFH and/or CFHL1 by recombinant BbCRASP-2 proteins. To conclusively define the effects of BbCRASP-2 residue substitutions on serum sensitivity in the bacterial context, a serum-sensitive Borrelia garinii strain was transformed with plasmids that directed production of either wild-type or mutated BbCRASP-2 proteins. Critical amino acid residues within BbCRASP-2 were identified, with bacteria producing distinct mutant proteins being unable to bind either CFH or CFHL1, showing high levels of complement components C3, C6, and C5b-9 deposited on their surfaces and being highly sensitive to killing by normal serum. Collectively, we mapped a structurally sensitive CFH/CFHL1 binding site within borrelial BbCRASP-2 and identified single amino acid residues potentially involved in the interaction with both complement regulators.
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Affiliation(s)
- Corinna Siegel
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Johanna Schreiber
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Katrin Haupt
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Christine Skerka
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Volker Brade
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Markus M. Simon
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Brian Stevenson
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Reinhard Wallich
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Peter F. Zipfel
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
| | - Peter Kraiczy
- Institute of Medical Microbiology and
Infection Control, University Hospital of Frankfurt, Paul-Ehrlich-Strasse 40,
60596 Frankfurt, Germany, the Department of
Infection Biology, Leibniz-Institute for Natural Products Research and
Infection Biology, 07745 Jena, Germany, the
Metschnikoff Laboratory, Max-Planck-Institute
for Immunobiology, 79108 Freiburg, Germany, the
Department of Microbiology, Immunology and
Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536, the
Institute of Immunology, University of Heidelberg,
69120 Heidelberg, Germany, and the
Friedrich Schiller University, 07743
Jena, Germany
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29
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Hakobyan S, Harris CL, van den Berg CW, Fernandez-Alonso MC, de Jorge EG, de Cordoba SR, Rivas G, Mangione P, Pepys MB, Morgan BP. Complement factor H binds to denatured rather than to native pentameric C-reactive protein. J Biol Chem 2008; 283:30451-60. [PMID: 18786923 PMCID: PMC2662140 DOI: 10.1074/jbc.m803648200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 08/20/2008] [Indexed: 11/06/2022] Open
Abstract
Binding of the complement regulatory protein, factor H, to C-reactive protein has been reported and implicated as the biological basis for association of the H402 polymorphic variant of factor H with macular degeneration. Published studies utilize solid-phase or fluid-phase binding assays to show that the factor H Y402 variant binds C-reactive protein more strongly than H402. Diminished binding of H402 variant to C-reactive protein in retinal drusen is posited to permit increased complement activation, driving inflammation and pathology. We used well validated native human C-reactive protein and pure factor H Y402H variants to test interactions. When factor H variants were incubated with C-reactive protein in the fluid phase at physiological concentrations, no association occurred. When C-reactive protein was immobilized on plastic, either non-specifically by adsorption in the presence of Ca(2+) to maintain its native fold and pentameric subunit assembly or by specific Ca(2+)-dependent binding to immobilized natural ligands, no specific binding of either factor H variant from the fluid phase was observed. In contrast, both factor H variants reproducibly bound to C-reactive protein immobilized in the absence of Ca(2+), conditions that destabilize the native fold and pentameric assembly. Both factor H variants strongly bound C-reactive protein that was denatured by heat treatment before immobilization, confirming interaction with denatured but not native C-reactive protein. We conclude that the reported binding of factor H to C-reactive protein results from denaturation of the C-reactive protein during immobilization. Differential binding to C-reactive protein, thus, does not explain association of the Y402H polymorphism with macular degeneration.
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Affiliation(s)
- Svetlana Hakobyan
- Department of Medical Biochemistry and Immunology and Pharmacology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
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30
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Sjöberg AP, Manderson GA, Mörgelin M, Day AJ, Heinegård D, Blom AM. Short leucine-rich glycoproteins of the extracellular matrix display diverse patterns of complement interaction and activation. Mol Immunol 2008; 46:830-9. [PMID: 18962898 DOI: 10.1016/j.molimm.2008.09.018] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 07/29/2008] [Accepted: 09/07/2008] [Indexed: 11/17/2022]
Abstract
The extracellular matrix consists of structural macromolecules and other proteins with regulatory functions. An important family of the latter class of molecules found in most tissues is the small leucine-rich repeat proteins (SLRPs). We have previously shown that the SLRP fibromodulin binds directly to C1q and activates the classical pathway of complement. In the present study we further examine the interactions between SLRPs and complement. Osteoadherin, like fibromodulin, binds C1q and activates the classical pathway strongly while moderate activation is seen in the terminal pathway. This can be explained by the interaction of fibromodulin and osteoadherin with factor H, a major soluble inhibitor of complement. Also, chondroadherin was found to bind C1q and activate complement, albeit to a lesser extent. Chondroadherin also binds factor H. We confirm published data showing that biglycan and decorin bind C1q but do not activate complement. In this study a similar pattern is seen for lumican although its affinity for C1q is lower than for biglycan and decorin. Furthermore, using electron microscopy and radiolabeled SLRPs, we demonstrate two different classes of SLRP binding sites on C1q, to head and stalk respectively, where only binding to the head appears to be activating. We propose a role for SLRPs in the regulation of complement activation in diseases involving the extracellular matrix, particularly those characterized by chronic inflammation such as rheumatoid arthritis, atherosclerosis, osteoarthritis and chronic obstructive lung disease.
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Affiliation(s)
- Andreas P Sjöberg
- Department of Laboratory Medicine, University Hospital Malmö, Lund University, Malmö, Sweden
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31
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Barlow PN, Hageman GS, Lea SM. Complement factor H: using atomic resolution structure to illuminate disease mechanisms. Adv Exp Med Biol 2008; 632:117-142. [PMID: 19025119 PMCID: PMC4863441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Complement Factor H has recently come to the fore with variant forms implicated in a range of serious disease states. This review aims to bring together recent data concerning the structure and biological activity of this molecule to highlight the way in which a molecular understanding of function may open novel therapeutic possibilities. In particular we examine the evidence for and against the hypothesis that sequence variations in factor H may predispose to disease if they perturb its ability to recognise and respond appropriately to polyanionic carbohydrates on host surfaces that require protection from complement-mediated damage.
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Affiliation(s)
- Paul N. Barlow
- Schools of Chemistry and Biological Sciences, Joseph Black Chemistry Building, University of Edinburgh, Edinburgh EH9 2PB, UK
| | - Gregory S. Hageman
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Susan M. Lea
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
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32
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Prosser BE, Johnson S, Roversi P, Herbert AP, Blaum BS, Tyrrell J, Jowitt TA, Clark SJ, Tarelli E, Uhrín D, Barlow PN, Sim RB, Day AJ, Lea SM. Structural basis for complement factor H linked age-related macular degeneration. J Exp Med 2007; 204:2277-83. [PMID: 17893204 PMCID: PMC2118454 DOI: 10.1084/jem.20071069] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 08/31/2007] [Indexed: 11/04/2022] Open
Abstract
Nearly 50 million people worldwide suffer from age-related macular degeneration (AMD), which causes severe loss of central vision. A single-nucleotide polymorphism in the gene for the complement regulator factor H (FH), which causes a Tyr-to-His substitution at position 402, is linked to approximately 50% of attributable risks for AMD. We present the crystal structure of the region of FH containing the polymorphic amino acid His402 in complex with an analogue of the glycosaminoglycans (GAGs) that localize the complement regulator on the cell surface. The structure demonstrates direct coordination of ligand by the disease-associated polymorphic residue, providing a molecular explanation of the genetic observation. This glycan-binding site occupies the center of an extended interaction groove on the regulator's surface, implying multivalent binding of sulfated GAGs. This finding is confirmed by structure-based site-directed mutagenesis, nuclear magnetic resonance-monitored binding experiments performed for both H402 and Y402 variants with this and another model GAG, and analysis of an extended GAG-FH complex.
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Affiliation(s)
- Beverly E Prosser
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, England, UK
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33
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Rossmann E, Kraiczy P, Herzberger P, Skerka C, Kirschfink M, Simon MM, Zipfel PF, Wallich R. Dual binding specificity of a Borrelia hermsii-associated complement regulator-acquiring surface protein for factor H and plasminogen discloses a putative virulence factor of relapsing fever spirochetes. J Immunol 2007; 178:7292-301. [PMID: 17513779 DOI: 10.4049/jimmunol.178.11.7292] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Tick-borne relapsing fever in North America is primarily caused by the spirochete Borrelia hermsii. The pathogen employs multiple strategies, including the acquisition of complement regulators and antigenic variation, to escape innate and humoral immunity. In this study we identified in B. hermsii a novel member of the complement regulator-acquiring surface protein (CRASP) family, designated BhCRASP-1, that binds the complement regulators factor H (FH) and FH-related protein 1 (FHR-1) but not FH-like protein 1 (FHL-1). BhCRASP-1 specifically interacts with the short consensus repeat 20 of FH, thereby maintaining FH-associated cofactor activity for factor I-mediated C3b inactivation. Furthermore, ectopic expression of BhCRASP- 1 converted the serum-sensitive Borrelia burgdorferi B313 strain into an intermediate complement-resistant strain. Finally, we report for the first time that BhCRASP-1 binds plasminogen/plasmin in addition to FH via, however, distinct nonoverlapping domains. The fact that surface-bound plasmin retains its proteolytic activity suggest that the dual binding specificity of BhCRASP-1 for FH and plasminogen/plasmin contributes to both the dissemination/invasion of B. hermsii and its resistance to innate immunity.
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Affiliation(s)
- Evelyn Rossmann
- Infectious Immunology Group, Institute for Immunology, University of Heidelberg, Heidelberg, Germany
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34
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Hammerschmidt S, Agarwal V, Kunert A, Haelbich S, Skerka C, Zipfel PF. The host immune regulator factor H interacts via two contact sites with the PspC protein of Streptococcus pneumoniae and mediates adhesion to host epithelial cells. J Immunol 2007; 178:5848-58. [PMID: 17442969 DOI: 10.4049/jimmunol.178.9.5848] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Pneumococcal surface protein C (PspC) of Streptococcus pneumoniae is a key virulence factor that mediates adhesion to host cells and immune evasion of the host complement. PspC binds the host immune and complement regulator factor H, which is composed of 20 short consensus repeats (SCR). This interaction contributes to pneumococcal virulence. In this study, we identified within the factor H protein two separate PspC binding regions, which were localized to SCR8-11 and SCR19-20, by using recombinant factor H deletion constructs for Western blotting assays and surface plasmon resonance studies. A detailed analysis of binding epitopes in these SCR by peptide spot arrays identified several linear binding regions within the sequences of SCR8-11 and SCR19-20. In addition, the factor H binding site was mapped within the pneumococcal PspC protein to a 121-aa-long stretch positioned in the N terminus (residues 38-158). Factor H attached to the surface of pneumococci via PspC significantly enhanced pneumococcal adherence to host epithelial and endothelial cells. This adhesion was specific and was blocked with a truncated N-terminal factor H-binding fragment of PspC. In conclusion, the acquisition of factor H by pneumococci via PspC occurs via two contact sites located in SCR8-11 and SCR19-20, and factor H attached to the surface of the pneumococcus promotes adhesion to both host epithelial and endothelial cells.
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Affiliation(s)
- Sven Hammerschmidt
- University of Wuerzburg, Research Center for Infectious Diseases, Wuerzburg, Germany.
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35
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Wu Z, Lauer TW, Sick A, Hackett SF, Campochiaro PA. Oxidative stress modulates complement factor H expression in retinal pigmented epithelial cells by acetylation of FOXO3. J Biol Chem 2007; 282:22414-25. [PMID: 17558024 DOI: 10.1074/jbc.m702321200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Age-related macular degeneration (AMD), the leading cause of severe vision loss in the elderly, is a complex disease that results from genetic modifications that increase susceptibility to environmental exposures. Smoking, a major source of oxidative stress, increases the incidence and severity of AMD, and antioxidants slow progression, suggesting that oxidative stress plays a major role. Polymorphisms in the complement factor H (CFH) gene that reduce activity of CFH increase the risk of AMD. In this study we demonstrate an interaction between these two risk factors, because oxidative stress reduces the ability of an inflammatory cytokine, interferon-gamma, to increase CFH expression in retinal pigmented epithelial cells. The interferon-gamma-induced increase in CFH is mediated by transcriptional activation by STAT1, and its suppression by oxidative stress is mediated by acetylation of FOXO3, which enhances FOXO3 binding to the CFH promoter, reduces its binding to STAT1, inhibits STAT1 interaction with the CFH promoter, and reduces expression of CFH. Expression of SIRT1, a mammalian homolog of NAD-dependent protein deacetylase sir2, attenuated FOXO3 recruitment to the CFH regulatory region and reversed the H(2)O(2)-induced repression of CFH gene expression. These data suggest an important interaction between environmental exposure and genetic susceptibility in the pathogenesis of AMD and, by elucidating molecular signaling involved in the interaction, provide potential targets for therapeutic intervention.
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Affiliation(s)
- Zhihao Wu
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA
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36
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Herbert AP, Deakin JA, Schmidt CQ, Blaum BS, Egan C, Ferreira VP, Pangburn MK, Lyon M, Uhrín D, Barlow PN. Structure Shows That a Glycosaminoglycan and Protein Recognition Site in Factor H Is Perturbed by Age-related Macular Degeneration-linked Single Nucleotide Polymorphism. J Biol Chem 2007; 282:18960-8. [PMID: 17360715 DOI: 10.1074/jbc.m609636200] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A common single nucleotide polymorphism in the factor H gene predisposes to age-related macular degeneration. Factor H blocks the alternative pathway of complement on self-surfaces bearing specific polyanions, including the glycosaminoglycan chains of proteoglycans. Factor H also binds C-reactive protein, potentially contributing to noninflammatory apoptotic processes. The at risk sequence contains His (rather than Tyr) at position 402 (384 in the mature protein), in the seventh of the 20 complement control protein (CCP) modules (CCP7) of factor H. We expressed both His(402) and Tyr(402) variants of CCP7, CCP7,8, and CCP6-8. We determined structures of His(402) and Tyr(402) CCP7 and showed them to be nearly identical. The side chains of His/Tyr(402) have similar, solvent-exposed orientations far from interfaces with CCP6 and -8. Tyr(402) CCP7 bound significantly more tightly than His(402) CCP7 to a heparin affinity column as well as to defined-length sulfated heparin oligosaccharides employed in gel mobility shift assays. This observation is consistent with the position of the 402 side chain on the edge of one of two glycosaminoglycan-binding surface patches on CCP7 that we inferred on the basis of chemical shift perturbation studies with a sulfated heparin tetrasaccharide. According to surface plasmon resonance measurements, Tyr(402) CCP6-8 binds significantly more tightly than His(402) CCP6-8 to immobilized C-reactive protein. The data support a causal link between H402Y and age-related macular degeneration in which variation at position 402 modulates the response of factor H to age-related changes in the glycosaminoglycan composition and apoptotic activity of the macula.
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Affiliation(s)
- Andrew P Herbert
- Edinburgh Biomolecular NMR Unit, School of Chemistry and School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, United Kingdom
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37
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Prosser BE, Johnson S, Roversi P, Clark SJ, Tarelli E, Sim RB, Day AJ, Lea SM. Expression, purification, cocrystallization and preliminary crystallographic analysis of sucrose octasulfate/human complement regulator factor H SCRs 6-8. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:480-3. [PMID: 17554167 PMCID: PMC2335081 DOI: 10.1107/s1744309107020052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 04/22/2007] [Indexed: 11/11/2022]
Abstract
Human plasma protein complement factor H (FH) is an inhibitor of the spontaneously activated alternative complement pathway. An allotypic variant of FH, 402His, has been associated with age-related macular degeneration, the leading cause of blindness in the elderly. Crystals of FH domains 6-8 (FH678) containing 402His have been grown in the presence of a polyanionic sucrose octasulfate ligand (an analogue of the natural glycosaminoglycan ligands of FH) using both native and selenomethionine-derivatized protein. Native data sets diffracting to 2.3 A and SeMet data sets of up to 2.8 A resolution have been collected. An anomalous difference Patterson map reveals self- and cross-peaks from two incorporated Se atoms. The corresponding selenium substructure has been solved.
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Affiliation(s)
- Beverly E. Prosser
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Steven Johnson
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Pietro Roversi
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Simon J. Clark
- Faculty of Life Sciences, Manchester University, Michael Smith Building, Oxford Road, Manchester M13 9PT, England
| | - Edward Tarelli
- Medical Biomics Centre, St George’s, University of London, Cranmer Terrace, London SW17 0RE, England
| | - Robert B. Sim
- The MRC Immunochemistry Unit, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Antony J. Day
- Faculty of Life Sciences, Manchester University, Michael Smith Building, Oxford Road, Manchester M13 9PT, England
| | - Susan M. Lea
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
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38
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Fenaille F, Le Mignon M, Groseil C, Ramon C, Riandé S, Siret L, Bihoreau N. Site-specific N-glycan characterization of human complement factor H. Glycobiology 2007; 17:932-44. [PMID: 17591618 DOI: 10.1093/glycob/cwm060] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Human complement factor H (CFH) is a plasma glycoprotein involved in the regulation of the alternative pathway of the complement system. A deficiency in CFH is a cause of severe pathologies like atypical haemolytic uraemic syndrome (aHUS). CFH is a 155-kDa glycoprotein containing nine potential N-glycosylation sites. In the current study, we present a quantitative glycosylation analysis of CFH using capillary electrophoresis and a complete site-specific N-glycan characterization using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESIMS/MS). A 17.9-kDa mass decrease, observed after glycosidase treatment, indicated that N-glycosylation is the major post-translational modification of CFH. This mass difference is consistent with CFH glycosylation by diantennary disialylated glycans of 2204 Da on eight sites. CFH was not sensitive to endoglycosidase H (Endo H) deglycosylation, indicating the absence of hybrid and oligomannose structures. Quantitative analysis showed that CFH is mainly glycosylated by complex, diantennary disialylated, non-fucosylated glycans. Disialylated fucosylated and monosialylated non-fucosylated oligosaccharides were also identified. MS analysis allowed complete characterization of the protein backbone, verification of the glycosylation sites and site-specific N-glycan identification. The absence of glycosylation at Asn199 of the NGSP sequence of CFH is shown. Asn511, Asn700, Asn784, Asn804, Asn864, Asn893, Asn1011 and Asn1077 are glycosylated essentially by diantennary disialylated structures with a relative distribution varying between 45% for Asn804 and 75% for Asn864. Diantennary monosialylated glycans and triantennary trisialylated fucosylated and non-fucosylated structures have also been identified. Interestingly, the sialylation level along with the amount of triantennary structures decreases from the N- to the C-terminal side of the protein.
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Affiliation(s)
- François Fenaille
- Laboratoire français du Fractionnement et des Biotechnologies, Développement Biopharmaceutique, 3 avenue des Tropiques, BP305 Les Ulis, 91958 Courtaboeuf cedex, France
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39
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Fernando AN, Furtado PB, Clark SJ, Gilbert HE, Day AJ, Sim RB, Perkins SJ. Associative and structural properties of the region of complement factor H encompassing the Tyr402His disease-related polymorphism and its interactions with heparin. J Mol Biol 2007; 368:564-81. [PMID: 17362990 DOI: 10.1016/j.jmb.2007.02.038] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Revised: 02/07/2007] [Accepted: 02/14/2007] [Indexed: 10/23/2022]
Abstract
Factor H (FH) is a major complement control protein in serum. The seventh short complement regulator (SCR-7) domain of the 20 in FH is associated with age-related macular degeneration through a Tyr402His polymorphism. The recombinant SCR-6/8 domains containing either His402 or Tyr402 and their complexes with a heparin decasaccharide were studied by analytical ultracentrifugation and X-ray scattering. The sedimentation coefficient is concentration dependent, giving a value of 2.0 S at zero concentration and a frictional ratio f/f(o) of 1.2 for both allotypes. The His402 allotype showed a slightly greater self-association than the Tyr402 allotype, and small amounts of dimeric SCR-6/8 were found for both allotypes in 50 mM, 137 mM and 250 mM NaCl buffers. Sedimentation equilibrium data were interpreted in terms of a monomer-dimer equilibrium with a dissociation constant of 40 microM for the His402 form. The Guinier radius of gyration R(G) of 3.1-3.3 nm and the R(G)/R(O) ratio of 2.0-2.1 showed that SCR-6/8 is relatively extended in solution. The distance distribution function P(r) showed a maximum dimension of 10 nm, which is less than the length expected for a linear domain arrangement. The constrained scattering and sedimentation modelling of FH SCR-6/8 showed that bent SCR arrangements fit the data better than linear arrangements. Previously identified heparin-binding residues were exposed on the outside curvature of this bent domain structure. Heparin caused the formation of a more linear structure, possibly by binding to residues in the linker. It was concluded that the His402 allotype may self-associate more readily than the Tyr402 allotype, SCR-6/8 is partly responsible for the folded-back structure of intact FH, and SCR-6/8 changes conformation upon heparin binding.
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Affiliation(s)
- Anira N Fernando
- Department of Biochemistry and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK
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40
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Herbert AP, Soares DC, Pangburn MK, Barlow PN. Disease-associated sequence variations in factor H: a structural biology approach. Adv Exp Med Biol 2007; 586:313-27. [PMID: 16893081 DOI: 10.1007/0-387-34134-x_21] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Andrew P Herbert
- School of Chemistry/Institute of Structural and Molecular Biology, University of Edinburgh, King's Buildings, Edinburgh EH9 3JJ, UK
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41
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Heinen S, Józsi M, Hartmann A, Noris M, Remuzzi G, Skerka C, Zipfel PF. Hemolytic Uremic Syndrome: A Factor H Mutation (E1172Stop) Causes Defective Complement Control at the Surface of Endothelial Cells. J Am Soc Nephrol 2007; 18:506-14. [PMID: 17229916 DOI: 10.1681/asn.2006091069] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Defective complement regulation results in hemolytic uremic syndrome (HUS), a disease that is characterized by microangiopathy, thrombocytopenia, and acute renal failure and that causes endothelial cell damage. For characterization of how defective complement regulation relates to the pathophysiology, the role of the complement regulator factor H and also of a mutant factor H protein was studied on the surface of human umbilical vein endothelial cells. The mutant 145-kD factor H protein was purified to homogeneity, from plasma of a patient with HUS, who is heterozygous for a factor H gene mutation G3587T, which introduces a stop codon at position 1172. Functional analyses show that the lack of the most C-terminal domain short consensus repeats 20 severely affected recognition functions (i.e., binding to heparin, C3b, C3d, and the surface of endothelial cells). Wild-type factor H as well as the mutant protein formed dimers in solution as shown by cross-linking studies and mass spectroscopy. When assayed in fluid phase, the complement regulatory activity of the mutant protein was normal and comparable to wild-type factor H. However, on the surface of endothelial cells, the mutant factor H protein showed severely reduced regulatory activities and lacked protective functions. Similarly, with the use of sheep erythrocytes, the mutant protein lacked the protective activity and caused increased hemolysis when it was added to factor H-depleted plasma. This study shows how a mutation that affects the C-terminal region of the factor H protein leads to defective complement control on cell surfaces and damage to endothelial cells in patients with HUS. These effects explain how mutant factor H causes defective complement control and in HUS-particularly under condition of inflammation and complement activation-causes endothelial cell damage.
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Affiliation(s)
- Stefan Heinen
- Department of Infection Biology, Leibniz Institute for Natural Products Research and Infection Biology, Hans Knoell Institute, Beutenbergstrasse 11a, D-07745 Jena, Germany
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42
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Klaska I, Nowak JZ. [The role of complement in physiology and pathology]. POSTEP HIG MED DOSW 2007; 61:167-77. [PMID: 17410057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 03/08/2007] [Indexed: 05/14/2023] Open
Abstract
The complement system was discovered over one hundred years ago. It is an essential part of the innate immune system. A group of about 40 proteins assists in phagocytosis and stimulates inflammation. The complement system participates in the defense of an organism against different factors, e.g. microorganisms. There are three pathways of complement activation: the classical, lectin, and alternative. Activation of the complement system leads to the formation of a lytic macromolecule known as the membrane attack complex (MAC). The MAC may damage target cells in a process called bacteriolysis. The host organism is protected against the negative impact of autoimmunity by complement factor H (CFH). Recent experimental studies dealing with the regulation of the complement system suggest that this control process can be genetically determined. Mutations in genes encoding CFH (CFH polymorphism), factor B, and C2, can be crucial for a defective or insufficient regulation of the complement system. This paper surveys recent achievements on the structure and mechanisms of the complement system and shortly reviews the correlation between the complement function and pathogenesis of many diseases, including atypical hemolytic uremic syndrome (aHUS), membranoproliferative glomerulonephritis II (MPGN II), and age-related macular degeneration (AMD).
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Affiliation(s)
- Izabela Klaska
- Centrum Biologii Medycznej, Polska Akademia Nauk, Łódź, Poland
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Alexander JJ, Quigg RJ. The simple design of complement factor H: Looks can be deceiving. Mol Immunol 2007; 44:123-32. [PMID: 16919753 DOI: 10.1016/j.molimm.2006.07.287] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2006] [Revised: 07/13/2006] [Accepted: 07/13/2006] [Indexed: 01/15/2023]
Abstract
The complement system is a powerful component of innate immunity which recognizes and facilitates the elimination of pathogens and unwanted host material. Since complement can also lead to host tissue injury and inflammation, strict regulation of its activation is important. One of the key regulators is complement factor H (CFH), a protein with an ever-expanding list of relevant functions. Inherited mutations in CFH can account for membranoproliferative glomerulonephritis (MPGN) type II, atypical hemolytic uremic syndrome, and age-related macular degeneration. The former can be associated with excessive systemic complement activation from dysfunctional CFH, while the latter two are associated with mutations affecting the ability of CFH to bind to anionic surfaces such as on endothelial cells and glomerular and retinal capillary walls. Mice with targeted deletion of CFH can spontaneously develop MPGN and have increased susceptibility to models of GN. In the rodent, CFH on platelets functions as the immune adherence receptor, analogous to CR1 on primate erythrocytes. In mice, platelets lacking CFH are unable to effectively clear immune complexes which results in their accumulation in glomeruli. The same switch also appears to be true in the rodent podocyte where CFH is present in place of CR1 in human podocytes. Thus, CFH has a variety of functions which can affect the diverse roles the complement system plays in health and disease.
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Affiliation(s)
- Jessy J Alexander
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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44
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Fenaille F, Le Mignon M, Groseil C, Siret L, Bihoreau N. Combined use of 2,4,6-trihydroxyacetophenone as matrix and enzymatic deglycosylation in organic-aqueous solvent systems for the simultaneous characterization of complex glycoproteins and N-glycans by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rapid Commun Mass Spectrom 2007; 21:812-6. [PMID: 17279484 DOI: 10.1002/rcm.2886] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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45
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Fujita T, Fujioka T, Murakami T, Satomura A, Fuke Y, Matsumoto K. Chylomicron accelerates C3 tick-over by regulating the role of factor H, leading to overproduction of acylation stimulating protein. J Clin Lab Anal 2007; 21:14-23. [PMID: 17245758 PMCID: PMC6649021 DOI: 10.1002/jcla.20158] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Accepted: 09/28/2006] [Indexed: 11/09/2022] Open
Abstract
Acylation stimulating protein (ASP) is a fragment of the third component of complement (C3) that is generated in the presence of chylomicron, and plays a role in the synthesis of triacylglycerol by transporting free fatty acids into adipocytes. However, the precise mechanism of ASP generation, especially the role of chylomicron in ASP generation, is unknown. We examined the mechanism through which chylomicron induces ASP generation. Ultracentrifugationally separated chylomicron was incubated with normal human serum (NHS) under various conditions, and the amounts of complement activation products and ASP in the incubation mixture were determined by enzyme-linked immunosorbent assay (ELISA). Upon incubation of NHS with various amounts of chylomicron for 120 min, ASP was generated in a dose-dependent manner. The time course of the production of ASP was similar to the time course of the C3 tick-over phenomenon that occurred by depletion of factor H from the serum. The complement activation induced by chylomicron was different from the usual complement activation that occurs under the regulation of factor H and factor I with respect to the time course and the amount of ASP produced. Our results indicate that chylomicron accelerates C3 tick-over by regulating the role of factor H, leading to the overproduction of ASP.
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Affiliation(s)
- Takayuki Fujita
- Division of Nephrology and Endocrinology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
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46
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Saunders RE, Goodship THJ, Zipfel PF, Perkins SJ. An interactive web database of factor H-associated hemolytic uremic syndrome mutations: insights into the structural consequences of disease-associated mutations. Hum Mutat 2006; 27:21-30. [PMID: 16281287 DOI: 10.1002/humu.20268] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Factor H (FH) is a central complement regulator comprised of 20 short complement repeat (SCR) domains. Nucleotide changes within this gene (CFH) have been observed in patients with hemolytic uremic syndrome (HUS), and also membranoproliferative glomerulonephritis and age-related macular degeneration. All parts of FH are affected, but many mutations are clustered in the C-terminal part of FH. Up to now, structural analyses of HUS have been based on SCR-20, a domain that is involved in FH interactions with C3b, heparin, and endothelial cells. In order to identify the structural and functional consequence of HUS mutations, further disease-associated mutations were analyzed in terms of homology and nuclear magnetic resonance (NMR) models for factor H SCR domains. An interactive web database of 54 human HUS-associated mutations and others was created from the literature (www.FH-HUS.org). This has comprehensive search and analysis tools, integrating phenotypic and genetic data with structural analysis. Each mutation can be highlighted on the SCR structure together with the patient FH and C3 levels where available. Two new insights were obtained from our collection of data. First, phenotypic data on FH clarify our previously-proposed classification of Type I and Type II disorders that both lead to HUS, where Type I affects FH secretion and folding, and Type II leads to expressed protein in plasma that is functionally defective. Second, the new mutations show more clearly that SCR domains from SCR-16 to SCR-19 are important for the ligand binding activities of FH as well as SCR-20. This FH web database will facilitate the interpretation of new mutations and polymorphisms when these are identified in patients, and it will clarify the functional role of FH.
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Affiliation(s)
- Rebecca E Saunders
- Department of Biochemistry and Molecular Biology, Royal Free and University College Medical School, University College London, London, United Kingdom
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Chung KM, Liszewski MK, Nybakken G, Davis AE, Townsend RR, Fremont DH, Atkinson JP, Diamond MS. West Nile virus nonstructural protein NS1 inhibits complement activation by binding the regulatory protein factor H. Proc Natl Acad Sci U S A 2006; 103:19111-6. [PMID: 17132743 PMCID: PMC1664712 DOI: 10.1073/pnas.0605668103] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The complement system, by virtue of its dual effector and priming functions, is a major host defense against pathogens. Flavivirus nonstructural protein (NS)-1 has been speculated to have immune evasion activity, because it is a secreted glycoprotein, binds back to cell surfaces, and accumulates to high levels in the serum of infected patients. Herein, we demonstrate an immunomodulatory function of West Nile virus NS1. Soluble and cell-surface-associated NS1 binds to and recruits the complement regulatory protein factor H, resulting in decreased complement activation in solution and attenuated deposition of C3 fragments and C5b-9 membrane attack complexes on cell surfaces. Accordingly, extracellular NS1 may function to minimize immune system targeting of West Nile virus by decreasing complement recognition of infected cells.
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Affiliation(s)
| | | | | | - Alan E. Davis
- Departments of *Medicine
- Cell Biology and Physiology, and
| | | | | | - John P. Atkinson
- Departments of *Medicine
- Pathology and Immunology
- Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Michael S. Diamond
- Departments of *Medicine
- Pathology and Immunology
- Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
- To whom correspondence should be addressed. E-mail:
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Banda NK, Thurman JM, Kraus D, Wood A, Carroll MC, Arend WP, Holers VM. Alternative Complement Pathway Activation Is Essential for Inflammation and Joint Destruction in the Passive Transfer Model of Collagen-Induced Arthritis. J Immunol 2006; 177:1904-12. [PMID: 16849503 DOI: 10.4049/jimmunol.177.3.1904] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of each complement initiation pathway (classical, alternative, and lectin) can lead to the generation of bioactive fragments with resulting inflammation in target organs. The objective of the current study was to determine the role of specific complement activation pathways in the pathogenesis of experimental anti-type II collagen mAb-passive transfer arthritis. C57BL/6 mice were used that were genetically deficient in either the alternative pathway protein factor B (Bf(-/-)) or in the classical pathway component C4 (C4(-/-)). Clinical disease activity was markedly decreased in Bf(-/-) compared with wild-type (WT) mice (0.5 +/- 0.22 (n = 6) in Bf(-/-) vs 8.83 +/- 0.41 (n = 6) in WT mice (p < 0.0001)). Disease activity scores were not different between C4(-/-) and WT mice. Analyses of joints showed that C3 deposition, inflammation, pannus, cartilage, and bone damage scores were all significantly less in Bf(-/-) as compared with WT mice. There were significant decreases in mRNA levels of C3, C4, CR2, CR3, C3aR, and C5aR in the knees of Bf(-/-) as compared with C4(-/-) and WT mice with arthritis; mRNA levels for complement regulatory proteins did not differ between the three strains. These results indicate that the alternative pathway is absolutely required for the induction of arthritis following injection of anti-collagen Abs. The mechanisms by which these target organ-specific mAbs bypass the requirements for engagement of the classical pathway remain to be defined but do not appear to involve a lack of alternative pathway regulatory proteins.
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MESH Headings
- Animals
- Antibodies, Monoclonal/administration & dosage
- Arthritis, Experimental/genetics
- Arthritis, Experimental/immunology
- Arthritis, Experimental/pathology
- Cartilage, Articular/immunology
- Cartilage, Articular/pathology
- Collagen/immunology
- Complement C3/chemistry
- Complement C4/deficiency
- Complement C4/genetics
- Complement Factor B/deficiency
- Complement Factor B/genetics
- Complement Factor H/chemistry
- Complement Inactivator Proteins/biosynthesis
- Complement Inactivator Proteins/genetics
- Complement Pathway, Alternative/immunology
- Cytokines/biosynthesis
- Cytokines/genetics
- Disease Models, Animal
- Immunization, Passive/methods
- Immunohistochemistry
- Inflammation/genetics
- Inflammation/immunology
- Inflammation/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- RNA, Messenger/biosynthesis
- Synovial Membrane/immunology
- Synovial Membrane/metabolism
- Synovial Membrane/pathology
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Affiliation(s)
- Nirmal K Banda
- Divisions of Rheumatology, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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49
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Singh AK, Mullick J, Bernet J, Sahu A. Functional characterization of the complement control protein homolog of herpesvirus saimiri: ARG-118 is critical for factor I cofactor activities. J Biol Chem 2006; 281:23119-28. [PMID: 16760474 DOI: 10.1074/jbc.m603085200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Herpesvirus saimiri (HVS) is a lymphotropic virus that causes T-cell lymphomas in New World primates. It encodes a structural homolog of complement control proteins named complement control protein homolog (CCPH). Previously, CCPH has been shown to inhibit C3d deposition on target cells exposed to complement. Here we have studied the mechanism by which it inactivates complement. We have expressed the soluble form of CCPH in Escherichia coli, purified to homogeneity and compared its activity to vaccinia virus complement control protein (VCP) and human complement regulators factor H and soluble complement receptor 1. The expressed soluble form of CCPH bound to C3b (KD = 19.2 microm) as well as to C4b (KD = 0.8 microm) and accelerated the decay of the classical/lectin as well as alternative pathway C3-convertases. In addition, it also served as factor I cofactor and supported factor I-mediated inactivation of both C3b and C4b. Time course analysis indicated that although its rate of inactivation of C4b is comparable with VCP, it is 14-fold more potent than VCP in inactivating C3b. Site-directed mutagenesis revealed that Arg-118, which corresponds to Lys-120 of variola virus complement regulator SPICE (a residue critical for its enhanced C3b cofactor activity), contributes significantly in enhancing this activity. Thus, our data indicate that HVS encodes a potent complement inhibitor that allows HVS to evade the host complement attack.
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Affiliation(s)
- Akhilesh K Singh
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
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50
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Jokiranta TS, Jaakola VP, Lehtinen MJ, Pärepalo M, Meri S, Goldman A. Structure of complement factor H carboxyl-terminus reveals molecular basis of atypical haemolytic uremic syndrome. EMBO J 2006; 25:1784-94. [PMID: 16601698 PMCID: PMC1440827 DOI: 10.1038/sj.emboj.7601052] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Accepted: 02/28/2006] [Indexed: 11/08/2022] Open
Abstract
Factor H (FH) is the key regulator of the alternative pathway of complement. The carboxyl-terminal domains 19-20 of FH interact with the major opsonin C3b, glycosaminoglycans, and endothelial cells. Mutations within this area are associated with atypical haemolytic uremic syndrome (aHUS), a disease characterized by damage to endothelial cells, erythrocytes, and kidney glomeruli. The structure of recombinant FH19-20, solved at 1.8 A by X-ray crystallography, reveals that the short consensus repeat domain 20 contains, unusually, a short alpha-helix, and a patch of basic residues at its base. Most aHUS-associated mutations either destabilize the structure or cluster in a unique region on the surface of FH20. This region is close to, but distinct from, the primary heparin-binding patch of basic residues. By mutating five residues in this region, we show that it is involved, not in heparin, but in C3b binding. Therefore, the majority of the aHUS-associated mutations on the surface of FH19-20 interfere with the interaction between FH and C3b. This obviously leads to impaired control of complement attack on plasma-exposed cell surfaces in aHUS.
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Affiliation(s)
- T Sakari Jokiranta
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland.
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