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Biggs RM, Makou E, Lauder S, Herbert AP, Barlow PN, Katti SK. An Evaluation of the Complement-Regulating Activities of Human Complement Factor H (FH) Variants Associated With Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2022; 63:30. [DOI: 10.1167/iovs.63.12.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Robyn M. Biggs
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Scott Lauder
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
| | - Andrew P. Herbert
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Paul N. Barlow
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
- School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Suresh K. Katti
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
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Biggs RM, Makou E, Lauder S, Herbert AP, Barlow PN, Katti SK. A Novel Full-Length Recombinant Human Complement Factor H (CFH; GEM103) for the Treatment of Age-Related Macular Degeneration Shows Similar In Vitro Functional Activity to Native CFH. Curr Eye Res 2022; 47:1087-1093. [PMID: 35282732 DOI: 10.1080/02713683.2022.2053725] [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: 12/15/2021] [Revised: 03/03/2022] [Accepted: 03/07/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE GEM103 is a recombinantly produced full-length version of the human complement factor H (CFH) under clinical investigation for treatment of age-related macular degeneration (AMD) in individuals carrying an AMD risk-associated genetic variant of CFH. This study aimed to investigate the complement pathway-related functions of GEM103 in comparison with those of native human CFH. METHODS Key biological activities of GEM103 and human serum-derived CFH (sdCFH) were compared using four independent functional assays. Assays of C3b binding and C3 convertase decay-accelerating activity (DAA) were performed by surface plasmon resonance (SPR). Cofactor activity (CA) was measured using 8-anilinonaphthalene-1-sulfonic acid as a fluorescent probe of C3b integrity. The abilities of GEM103 and sdCFH to protect sheep erythrocytes from hemolysis by CFH-depleted normal human serum were assessed colorimetrically. RESULTS In multiple SPR-based assays of C3b binding and DAA, the performance of GEM103 was consistently comparable to that of sdCFH across a range of matching concentrations. The EC50 ± SD in the fluorescence-based fluid-phase CA assay was 0.21 ± 0.06 µM for GEM103 compared to 0.20 ± 0.09 µM for sdCFH. In hemolysis assays, the EC50 value of 0.33 ± 0.16 µM for GEM103 versus 0.46 ± 0.06 µM for sdCFH were not significantly different (p = 0.81). CONCLUSIONS GEM103, a recombinant CFH developed by Gemini Therapeutics, shows activity profiles comparable to sdCFH in all complement-related assays employed in this study, suggesting that GEM103 is equivalent to the native glycoprotein in terms of its in vitro functional activity. These results support further study of GEM103 as a potential therapy for AMD.
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Affiliation(s)
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh, UK
| | | | | | - Paul N Barlow
- School of Chemistry, University of Edinburgh, Edinburgh, UK
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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Kerr H, Herbert AP, Makou E, Abramczyk D, Malik TH, Lomax-Browne H, Yang Y, Pappworth IY, Denton H, Richards A, Marchbank KJ, Pickering MC, Barlow PN. Murine Factor H Co-Produced in Yeast With Protein Disulfide Isomerase Ameliorated C3 Dysregulation in Factor H-Deficient Mice. Front Immunol 2021; 12:681098. [PMID: 34054871 PMCID: PMC8149785 DOI: 10.3389/fimmu.2021.681098] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 03/15/2021] [Accepted: 04/22/2021] [Indexed: 12/05/2022] Open
Abstract
Recombinant human factor H (hFH) has potential for treating diseases linked to aberrant complement regulation including C3 glomerulopathy (C3G) and dry age-related macular degeneration. Murine FH (mFH), produced in the same host, is useful for pre-clinical investigations in mouse models of disease. An abundance of FH in plasma suggests high doses, and hence microbial production, will be needed. Previously, Pichia pastoris produced useful but modest quantities of hFH. Herein, a similar strategy yielded miniscule quantities of mFH. Since FH has 40 disulfide bonds, we created a P. pastoris strain containing a methanol-inducible codon-modified gene for protein-disulfide isomerase (PDI) and transformed this with codon-modified DNA encoding mFH under the same promoter. What had been barely detectable yields of mFH became multiple 10s of mg/L. Our PDI-overexpressing strain also boosted hFH overproduction, by about tenfold. These enhancements exceeded PDI-related production gains reported for other proteins, all of which contain fewer disulfide-stabilized domains. We optimized fermentation conditions, purified recombinant mFH, enzymatically trimmed down its (non-human) N-glycans, characterised its functions in vitro and administered it to mice. In FH-knockout mice, our de-glycosylated recombinant mFH had a shorter half-life and induced more anti-mFH antibodies than mouse serum-derived, natively glycosylated, mFH. Even sequential daily injections of recombinant mFH failed to restore wild-type levels of FH and C3 in mouse plasma beyond 24 hours after the first injection. Nevertheless, mFH functionality appeared to persist in the glomerular basement membrane because C3-fragment deposition here, a hallmark of C3G, remained significantly reduced throughout and beyond the ten-day dosing regimen.
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Affiliation(s)
- Heather Kerr
- Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew P. Herbert
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Dariusz Abramczyk
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Talat H. Malik
- Centre for Inflammatory Disease, Imperial College London, London, United Kingdom
| | - Hannah Lomax-Browne
- Centre for Inflammatory Disease, Imperial College London, London, United Kingdom
| | - Yi Yang
- Translational and Clinical Research Institute, Newcastle University, Newcastle, United Kingdom
- National Renal Complement Therapeutics Center, Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Isabel Y. Pappworth
- Translational and Clinical Research Institute, Newcastle University, Newcastle, United Kingdom
- National Renal Complement Therapeutics Center, Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Harriet Denton
- Translational and Clinical Research Institute, Newcastle University, Newcastle, United Kingdom
- National Renal Complement Therapeutics Center, Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Anna Richards
- Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Kevin J. Marchbank
- Translational and Clinical Research Institute, Newcastle University, Newcastle, United Kingdom
- National Renal Complement Therapeutics Center, Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Matthew C. Pickering
- Centre for Inflammatory Disease, Imperial College London, London, United Kingdom
| | - Paul N. Barlow
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
- School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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Yang Y, Denton H, Davies OR, Smith-Jackson K, Kerr H, Herbert AP, Barlow PN, Pickering MC, Marchbank KJ. An Engineered Complement Factor H Construct for Treatment of C3 Glomerulopathy. J Am Soc Nephrol 2018; 29:1649-1661. [PMID: 29588430 PMCID: PMC6054357 DOI: 10.1681/asn.2017091006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [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: 09/20/2017] [Accepted: 02/26/2018] [Indexed: 01/06/2023] Open
Abstract
Background C3 glomerulopathy (C3G) is associated with dysregulation of the alternative pathway of complement activation, and treatment options for C3G remain limited. Complement factor H (FH) is a potent regulator of the alternative pathway and might offer a solution, but the mass and complexity of FH makes generation of full-length FH far from trivial. We previously generated a mini-FH construct, with FH short consensus repeats 1-5 linked to repeats 18-20 (FH1-5^18-20), that was effective in experimental C3G. However, the serum t1/2 of FH1-5^18-20 was significantly shorter than that of serum-purified FH.Methods We introduced the oligomerization domain of human FH-related protein 1 (denoted by R1-2) at the carboxy or amino terminus of human FH1-5^18-20 to generate two homodimeric mini-FH constructs (FHR1-2^1-5^18-20 and FH1-5^18-20^R1-2, respectively) in Chinese hamster ovary cells and tested these constructs using binding, fluid-phase, and erythrocyte lysis assays, followed by experiments in FH-deficient Cfh-/- mice.Results FHR1-2^1-5^18-20 and FH1-5^18-20^R1-2 homodimerized in solution and displayed avid binding profiles on clustered C3b surfaces, particularly FHR1-2^1-5^18-20 Each construct was >10-fold more effective than FH at inhibiting cell surface complement activity in vitro and restricted glomerular basement membrane C3 deposition in vivo significantly better than FH or FH1-5^18-20 FH1-5^18-20^R1-2 had a C3 breakdown fragment binding profile similar to that of FH, a >5-fold increase in serum t1/2 compared with that of FH1-5^18-20, and significantly better retention in the kidney than FH or FH1-5^18-20Conclusions FH1-5^18-20^R1-2 may have utility as a treatment option for C3G or other complement-mediated diseases.
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Affiliation(s)
- Yi Yang
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Harriet Denton
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Owen R Davies
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Kate Smith-Jackson
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Heather Kerr
- Department of Chemistry, Edinburgh University, Edinburgh, UK; and
| | - Andrew P Herbert
- Department of Chemistry, Edinburgh University, Edinburgh, UK; and
| | - Paul N Barlow
- Department of Chemistry, Edinburgh University, Edinburgh, UK; and
| | | | - Kevin J Marchbank
- Institute of Cellular Medicine, Newcastle University and National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK;
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Blatt AZ, Saggu G, Cortes C, Herbert AP, Kavanagh D, Ricklin D, Lambris JD, Ferreira VP. Factor H C-Terminal Domains Are Critical for Regulation of Platelet/Granulocyte Aggregate Formation. Front Immunol 2017; 8:1586. [PMID: 29218045 PMCID: PMC5703703 DOI: 10.3389/fimmu.2017.01586] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/03/2017] [Indexed: 11/16/2022] Open
Abstract
Platelet/granulocyte aggregates (PGAs) increase thromboinflammation in the vasculature, and PGA formation is tightly controlled by the complement alternative pathway (AP) negative regulator, Factor H (FH). Mutations in FH are associated with the prothrombotic disease atypical hemolytic uremic syndrome (aHUS), yet it is unknown whether increased PGA formation contributes to the thrombosis seen in patients with aHUS. Here, flow cytometry assays were used to evaluate the effects of aHUS-related mutations on FH regulation of PGA formation and characterize the mechanism. Utilizing recombinant fragments of FH spanning the entire length of the protein, we mapped the regions of FH most critical for limiting AP activity on the surface of isolated human platelets and neutrophils, as well as the regions most critical for regulating PGA formation in human whole blood stimulated with thrombin receptor-activating peptide (TRAP). FH domains 19–20 were the most critical for limiting AP activity on platelets, neutrophils, and at the platelet/granulocyte interface. The role of FH in PGA formation was attributed to its ability to regulate AP-mediated C5a generation. AHUS-related mutations in domains 19–20 caused differential effects on control of PGA formation and AP activity on platelets and neutrophils. Our data indicate FH C-terminal domains are key for regulating PGA formation, thus increased FH protection may have a beneficial impact on diseases characterized by increased PGA formation, such as cardiovascular disease. Additionally, aHUS-related mutations in domains 19–20 have varying effects on control of TRAP-mediated PGA formation, suggesting that some, but not all, aHUS-related mutations may cause increased PGA formation that contributes to excessive thrombosis in patients with aHUS.
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Affiliation(s)
- Adam Z Blatt
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Gurpanna Saggu
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Claudio Cortes
- Department of Biomedical Sciences, Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Andrew P Herbert
- The School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - David Kavanagh
- The National Renal Complement Therapeutics Centre, Newcastle upon Tyne, United Kingdom.,Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Daniel Ricklin
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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Kerr H, Wong E, Makou E, Yang Y, Marchbank K, Kavanagh D, Richards A, Herbert AP, Barlow PN. Disease-linked mutations in factor H reveal pivotal role of cofactor activity in self-surface-selective regulation of complement activation. J Biol Chem 2017. [PMID: 28637873 PMCID: PMC5555194 DOI: 10.1074/jbc.m117.795088] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spontaneous activation enables the complement system to respond very rapidly to diverse threats. This activation is efficiently suppressed by complement factor H (CFH) on self-surfaces but not on foreign surfaces. The surface selectivity of CFH, a soluble protein containing 20 complement-control protein modules (CCPs 1-20), may be compromised by disease-linked mutations. However, which of the several functions of CFH drives this self-surface selectivity remains unknown. To address this, we expressed human CFH mutants in Pichia pastoris We found that recombinant I62-CFH (protective against age-related macular degeneration) and V62-CFH functioned equivalently, matching or outperforming plasma-derived CFH, whereas R53H-CFH, linked to atypical hemolytic uremic syndrome (aHUS), was defective in C3bBb decay-accelerating activity (DAA) and factor I cofactor activity (CA). The aHUS-linked CCP 19 mutant D1119G-CFH had virtually no CA on (self-like) sheep erythrocytes (ES) but retained DAA. The aHUS-linked CCP 20 mutant S1191L/V1197A-CFH (LA-CFH) had dramatically reduced CA on ES but was less compromised in DAA. D1119G-CFH and LA-CFH both performed poorly at preventing complement-mediated hemolysis of ES PspCN, a CFH-binding Streptococcus pneumoniae protein domain, binds CFH tightly and increases accessibility of CCPs 19 and 20. PspCN did not improve the DAA of any CFH variant on ES Conversely, PspCN boosted the CA, on ES, of I62-CFH, R53H-CFH, and LA-CFH and also enhanced hemolysis protection by I62-CFH and LA-CFH. We conclude that CCPs 19 and 20 are critical for efficient CA on self-surfaces but less important for DAA. Exposing CCPs 19 and 20 with PspCN and thus enhancing CA on self-surfaces may reverse deficiencies of some CFH variants.
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Affiliation(s)
- Heather Kerr
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Edwin Wong
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Elisavet Makou
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Yi Yang
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Kevin Marchbank
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - David Kavanagh
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Anna Richards
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Andrew P Herbert
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Paul N Barlow
- From the Schools of Chemistry and Biological Sciences, Joseph Black Building, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
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Herbert AP, Makou E, Chen ZA, Kerr H, Richards A, Rappsilber J, Barlow PN. Complement Evasion Mediated by Enhancement of Captured Factor H: Implications for Protection of Self-Surfaces from Complement. J Immunol 2015; 195:4986-98. [PMID: 26459349 PMCID: PMC4635569 DOI: 10.4049/jimmunol.1501388] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/10/2015] [Indexed: 12/12/2022]
Abstract
In an attempt to evade annihilation by the vertebrate complement system, many microbes capture factor H (FH), the key soluble complement-regulating protein in human plasma. However, FH is normally an active complement suppressor exclusively on self-surfaces and this selective action of FH is pivotal to self versus non-self discrimination by the complement system. We investigated whether the bacterially captured FH becomes functionally enhanced and, if so, how this is achieved at a structural level. We found, using site-directed and truncation mutagenesis, surface plasmon resonance, nuclear magnetic resonance spectroscopy, and cross-linking and mass spectrometry, that the N-terminal domain of Streptococcus pneumoniae protein PspC (PspCN) not only binds FH extraordinarily tightly but also holds it in a previously uncharacterized conformation. Functional enhancement arises from exposure of a C-terminal cryptic second binding site in FH for C3b, the activation-specific fragment of the pivotal complement component, C3. This conformational change of FH doubles its affinity for C3b and increases 5-fold its ability to accelerate decay of the binary enzyme (C3bBb) responsible for converting C3 to C3b in an amplification loop. Despite not sharing critical FH-binding residues, PspCNs from D39 and Tigr4 S. pneumoniae exhibit similar FH-anchoring and enhancing properties. We propose that these bacterial proteins mimic molecular markers of self-surfaces, providing a compelling hypothesis for how FH prevents complement-mediated injury to host tissue while lacking efficacy on virtually all other surfaces. In hemolysis assays with 2-aminoethylisothiouronium bromide–treated erythrocytes that recapitulate paroxysmal nocturnal hemoglobinuria, PspCN enhanced protection of cells by FH, suggesting a new paradigm for therapeutic complement suppression.
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Affiliation(s)
- Andrew P Herbert
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Zhuo A Chen
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom; and
| | - Heather Kerr
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom; Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom
| | - Anna Richards
- Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom
| | - Juri Rappsilber
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom; and
| | - Paul N Barlow
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom;
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Blaum BS, Hannan JP, Herbert AP, Kavanagh D, Uhrín D, Stehle T. Structural basis for sialic acid-mediated self-recognition by complement factor H. Nat Chem Biol 2014; 11:77-82. [PMID: 25402769 DOI: 10.1038/nchembio.1696] [Citation(s) in RCA: 204] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 10/02/2014] [Indexed: 12/25/2022]
Abstract
The serum protein complement factor H (FH) ensures downregulation of the complement alternative pathway, a branch of innate immunity, upon interaction with specific glycans on host cell surfaces. Using ligand-based NMR, we screened a comprehensive set of sialylated glycans for binding to FH and solved the crystal structure of a ternary complex formed by the two C-terminal domains of FH, a sialylated trisaccharide and the complement C3b thioester-containing domain. Key residues in the sialic acid binding site are conserved from mice to men, and residues linked to atypical hemolytic uremic syndrome cluster within this binding site, suggesting a possible role for sialic acid as a host marker also in other mammals and a critical role in human renal complement homeostasis. Unexpectedly, the FH sialic acid binding site is structurally homologous to the binding sites of two evolutionarily unrelated proteins. The crystal structure also advances our understanding of bacterial immune evasion strategies.
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Affiliation(s)
- Bärbel S Blaum
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jonathan P Hannan
- Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | | | - David Kavanagh
- Institute of Genetic Medicine, International Centre for Life, Newcastle upon Tyne, UK
| | - Dušan Uhrín
- The School of Chemistry, University of Edinburgh, Scotland, UK
| | - Thilo Stehle
- 1] Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany. [2] Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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Wong EKS, Anderson HE, Herbert AP, Challis RC, Brown P, Reis GS, Tellez JO, Strain L, Fluck N, Humphrey A, Macleod A, Richards A, Ahlert D, Santibanez-Koref M, Barlow PN, Marchbank KJ, Harris CL, Goodship THJ, Kavanagh D. Characterization of a factor H mutation that perturbs the alternative pathway of complement in a family with membranoproliferative GN. J Am Soc Nephrol 2014; 25:2425-33. [PMID: 24722444 DOI: 10.1681/asn.2013070732] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Complement C3 activation is a characteristic finding in membranoproliferative GN (MPGN). This activation can be caused by immune complex deposition or an acquired or inherited defect in complement regulation. Deficiency of complement factor H has long been associated with MPGN. More recently, heterozygous genetic variants have been reported in sporadic cases of MPGN, although their functional significance has not been assessed. We describe a family with MPGN and acquired partial lipodystrophy. Although C3 nephritic factor was shown in family members with acquired partial lipodystrophy, it did not segregate with the renal phenotype. Genetic analysis revealed a novel heterozygous mutation in complement factor H (R83S) in addition to known risk polymorphisms carried by individuals with MPGN. Patients with MPGN had normal levels of factor H, and structural analysis of the mutant revealed only subtle alterations. However, functional analysis revealed profoundly reduced C3b binding, cofactor activity, and decay accelerating activity leading to loss of regulation of the alternative pathway. In summary, this family showed a confluence of common and rare functionally significant genetic risk factors causing disease. Data from our analysis of these factors highlight the role of the alternative pathway of complement in MPGN.
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Affiliation(s)
| | | | | | | | - Paul Brown
- The Renal Unit, Aberdeen Royal Infirmary, Aberdeen, United Kingdom; and
| | | | | | | | - Nicholas Fluck
- The Renal Unit, Aberdeen Royal Infirmary, Aberdeen, United Kingdom; and
| | - Ann Humphrey
- The Renal Unit, Aberdeen Royal Infirmary, Aberdeen, United Kingdom; and
| | - Alison Macleod
- The Renal Unit, Aberdeen Royal Infirmary, Aberdeen, United Kingdom; and
| | - Anna Richards
- Medical Research Council Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | - Paul N Barlow
- Edinburgh Biomolecular Nuclear Magnetic Resonance Unit, and
| | - Kevin J Marchbank
- Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Claire L Harris
- Cardiff Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
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Abstract
Factor H (FH) is a soluble regulator of the proteolytic cascade at the core of the evolutionarily ancient vertebrate complement system. Although FH consists of a single chain of similar protein modules, it has a demanding job description. Its chief role is to prevent complement-mediated injury to healthy host cells and tissues. This entails recognition of molecular patterns on host surfaces combined with control of one of nature's most dangerous examples of a positive-feedback loop. In this way, FH modulates, where and when needed, an amplification process that otherwise exponentially escalates the production of the pro-inflammatory, pro-phagocytic, and pro-cytolytic cleavage products of complement proteins C3 and C5. Mutations and single-nucleotide polymorphisms in the FH gene and autoantibodies against FH predispose individuals to diseases, including age-related macular degeneration, dense-deposit disease, and atypical hemolytic uremic syndrome. Moreover, deletions or variations of genes for FH-related proteins also influence the risk of disease. Numerous pathogens hijack FH and use it for self-defense. As reviewed herein, a molecular understanding of FH function is emerging. While its functional oligomeric status remains uncertain, progress has been achieved in characterizing its three-dimensional architecture and, to a lesser extent, its intermodular flexibility. Models are proposed, based on the reconciliation of older data with a wealth of recent evidence, in which a latent circulating form of FH is activated by its principal target, C3b tethered to a self-surface. Such models suggest hypotheses linking sequence variations to pathophysiology, but improved, more quantitative, functional assays and rigorous data analysis are required to test these ideas.
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Affiliation(s)
- Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, U.K
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Clark SJ, Ridge LA, Herbert AP, Hakobyan S, Mulloy B, Lennon R, Würzner R, Morgan BP, Uhrín D, Bishop PN, Day AJ. Tissue-specific host recognition by complement factor H is mediated by differential activities of its glycosaminoglycan-binding regions. J Immunol 2013; 190:2049-57. [PMID: 23365078 DOI: 10.4049/jimmunol.1201751] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Complement factor H (CFH) regulates complement activation in host tissues through its recognition of polyanions, which mediate CFH binding to host cell surfaces and extracellular matrix, promoting the deactivation of deposited C3b. These polyanions include heparan sulfate (HS), a glycosaminoglycan with a highly diverse range of structures, for which two regions of CFH (CCP6-8 and CCP19-20) have been implicated in HS binding. Mutations/polymorphisms within these glycosaminoglycan-binding sites have been associated with age-related macular degeneration (AMD) and atypical hemolytic uremic syndrome. In this study, we demonstrate that CFH has tissue-specific binding properties mediated through its two HS-binding regions. Our data show that the CCP6-8 region of CFH binds more strongly to heparin (a highly sulfated form of HS) than CCP19-20, and that their sulfate specificities are different. Furthermore, the HS binding site in CCP6-8, which is affected by the AMD-associated Y402H polymorphism, plays the principal role in host tissue recognition in the human eye, whereas the CCP19-20 region makes the major contribution to the binding of CFH in the human kidney. This helps provide a biochemical explanation for the genetic basis of tissue-specific diseases such as AMD and atypical hemolytic uremic syndrome, and leads to a better understanding of the pathogenic mechanisms for these diseases of complement dysregulation.
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Affiliation(s)
- Simon J Clark
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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12
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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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13
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Lesher AM, Zhou L, Kimura Y, Sato S, Gullipalli D, Herbert AP, Barlow PN, Eberhardt HU, Skerka C, Zipfel PF, Hamano T, Miwa T, Tung KS, Song WC. Combination of factor H mutation and properdin deficiency causes severe C3 glomerulonephritis. J Am Soc Nephrol 2012. [PMID: 23204401 DOI: 10.1681/asn.2012060570] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Factor H (fH) and properdin both modulate complement; however, fH inhibits activation, and properdin promotes activation of the alternative pathway of complement. Mutations in fH associate with several human kidney diseases, but whether inhibiting properdin would be beneficial in these diseases is unknown. Here, we found that either genetic or pharmacological blockade of properdin, which we expected to be therapeutic, converted the mild C3 GN of an fH-mutant mouse to a lethal C3 GN with features of human dense deposit disease. We attributed this phenotypic change to a differential effect of properdin on the dynamics of alternative pathway complement activation in the fluid phase and the cell surface in the fH-mutant mice. Thus, in fH mutation-related C3 glomerulopathy, additional factors that impact the activation of the alternative pathway of complement critically determine the nature and severity of kidney pathology. These results show that therapeutic manipulation of the complement system requires rigorous disease-specific target validation.
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Affiliation(s)
- Allison M Lesher
- Department of Pharmacology and Institute for Translational Medicine and Therapeutics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
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14
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Herbert AP, Makou E, Barlow PN. Structural characterization of the N-terminal region of Streptococcus pneumonia surface protein C. Immunobiology 2012. [DOI: 10.1016/j.imbio.2012.08.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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McCue HV, Patel P, Herbert AP, Lian LY, Burgoyne RD, Haynes LP. Solution NMR structure of the Ca2+-bound N-terminal domain of CaBP7: a regulator of golgi trafficking. J Biol Chem 2012; 287:38231-43. [PMID: 22989873 PMCID: PMC3488092 DOI: 10.1074/jbc.m112.402289] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Calcium-binding protein 7 (CaBP7) is a member of the calmodulin (CaM) superfamily that harbors two high affinity EF-hand motifs and a C-terminal transmembrane domain. CaBP7 has been previously shown to interact with and modulate phosphatidylinositol 4-kinase III-β (PI4KIIIβ) activity in in vitro assays and affects vesicle transport in neurons when overexpressed. Here we show that the N-terminal domain (NTD) of CaBP7 is sufficient to mediate the interaction of CaBP7 with PI4KIIIβ. CaBP7 NTD encompasses the two high affinity Ca2+ binding sites, and structural characterization through multiangle light scattering, circular dichroism, and NMR reveals unique properties for this domain. CaBP7 NTD binds specifically to Ca2+ but not Mg2+ and undergoes significant conformational changes in both secondary and tertiary structure upon Ca2+ binding. The Ca2+-bound form of CaBP7 NTD is monomeric and exhibits an open conformation similar to that of CaM. Ca2+-bound CaBP7 NTD has a solvent-exposed hydrophobic surface that is more expansive than observed in CaM or CaBP1. Within this hydrophobic pocket, there is a significant reduction in the number of methionine residues that are conserved in CaM and CaBP1 and shown to be important for target recognition. In CaBP7 NTD, these residues are replaced with isoleucine and leucine residues with branched side chains that are intrinsically more rigid than the flexible methionine side chain. We propose that these differences in surface hydrophobicity, charge, and methionine content may be important in determining highly specific interactions of CaBP7 with target proteins, such as PI4KIIIβ.
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Affiliation(s)
- Hannah V McCue
- Physiological Laboratory, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, United Kingdom
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16
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Herbert AP, Riesen M, Bloxam L, Kosmidou E, Wareing BM, Johnson JR, Phelan MM, Pennington SR, Lian LY, Morgan A. NMR structure of Hsp12, a protein induced by and required for dietary restriction-induced lifespan extension in yeast. PLoS One 2012; 7:e41975. [PMID: 22848679 PMCID: PMC3407059 DOI: 10.1371/journal.pone.0041975] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [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: 05/13/2012] [Accepted: 06/26/2012] [Indexed: 11/19/2022] Open
Abstract
Dietary restriction (DR) extends lifespan in yeast, worms, flies and mammals, suggesting that it may act via conserved processes. However, the downstream mechanisms by which DR increases lifespan remain unclear. We used a gel based proteomic strategy to identify proteins whose expression was induced by DR in yeast and thus may correlate with longevity. One protein up-regulated by DR was Hsp12, a small heat shock protein induced by various manipulations known to retard ageing. Lifespan extension by growth on 0.5% glucose (DR) was abolished in an hsp12Δ strain, indicating that Hsp12 is essential for the longevity effect of DR. In contrast, deletion of HSP12 had no effect on growth under DR conditions or a variety of environmental stresses, indicating that the effect of Hsp12 on lifespan is not due to increased general stress resistance. Unlike other small heat shock proteins, recombinant Hsp12 displayed negligible in vitro molecular chaperone activity, suggesting that its cellular function does not involve preventing protein aggregation. NMR analysis indicated that Hsp12 is monomeric and intrinsically unfolded in solution, but switches to a 4-helical conformation upon binding to membrane-mimetic SDS micelles. The structure of micelle-bound Hsp12 reported here is consistent with its recently proposed function as a membrane-stabilising 'lipid chaperone'. Taken together, our data suggest that DR-induced Hsp12 expression contributes to lifespan extension, possibly via membrane alterations.
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Affiliation(s)
- Andrew P. Herbert
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
- NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Michèle Riesen
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Leanne Bloxam
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Effie Kosmidou
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Brian M. Wareing
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - James R. Johnson
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Marie M. Phelan
- NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Stephen R. Pennington
- University College Dublin Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Dublin, Ireland
| | - Lu-Yun Lian
- NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Alan Morgan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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17
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Goodship THJ, Pappworth IY, Toth T, Denton M, Houlberg K, McCormick F, Warland D, Moore I, Hunze EM, Staniforth SJ, Hayes C, Cavalcante DP, Kavanagh D, Strain L, Herbert AP, Schmidt CQ, Barlow PN, Harris CL, Marchbank KJ. Factor H autoantibodies in membranoproliferative glomerulonephritis. Mol Immunol 2012; 52:200-6. [PMID: 22721707 DOI: 10.1016/j.molimm.2012.05.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 05/03/2012] [Accepted: 05/05/2012] [Indexed: 02/06/2023]
Abstract
Factor H autoantibodies are found in ~10% of aHUS patients. Most are associated with complete deficiency of factor H related proteins 1/3 and bind to the C terminal recognition domain. MPGN, like aHUS, is characterised by complement activation. In this study we, therefore, examined the hypothesis that factor H autoantibodies are associated with MPGN. We screened sera from 16 MPGN patients and 100 normal controls using ELISA and detected strongly positive IgG factor H autoantibodies in 2 patients. One patient had type II (DDD) MPGN (male aged 24 yrs) with C3NeF and the other type I (female aged 26 yrs) with no detectable C3NeF. We identified the binding site of the autoantibodies using small SCR domain fragments in the ELISA and showed that the autoantibodies in both patients bound predominately to the N terminal complement regulatory domain of factor H. We measured CFHR 1/3 copy number using MLPA and showed that both patients had 2 copies of CFHR1 and 3. Finally, we examined the functionality of detected factor H autoantibodies using purified patient IgG and observed increased haemolysis when purified IgG from both patients was added to normal human sera prior to incubation with rabbit red blood cells. Thus, in a cohort of MPGN patients we have found a high titre of functionally significant factor H autoantibodies in two patients with MPGN. Antibody depleting therapy may have a role in such patients and we suggest that screening for factor H autoantibodies should be undertaken in all patients with MPGN.
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Affiliation(s)
- Timothy H J Goodship
- Institutes of Cellular Medicine and Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
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18
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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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19
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Herbert AP, Kavanagh D, Johansson C, Morgan HP, Blaum BS, Hannan JP, Barlow PN, Uhrín D. Structural and functional characterization of the product of disease-related factor H gene conversion. Biochemistry 2012; 51:1874-84. [PMID: 22320225 DOI: 10.1021/bi201689j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Numerous complement factor H (FH) mutations predispose patients to atypical hemolytic uremic syndrome (aHUS) and other disorders arising from inadequately regulated complement activation. No unifying structural or mechanistic consequences have been ascribed to these mutants beyond impaired self-cell protection. The S1191L and V1197A mutations toward the C-terminus of FH, which occur in patients singly or together, arose from gene conversion between CFH encoding FH and CFHR1 encoding FH-related 1. We show that neither single nor double mutations structurally perturbed recombinant proteins consisting of the FH C-terminal modules, 19 and 20 (FH19-20), although all three FH19-20 mutants were poor, compared to wild-type FH19-20, at promoting hemolysis of C3b-coated erythrocytes through competition with full-length FH. Indeed, our new crystal structure of the S1191L mutant of FH19-20 complexed with an activation-specific complement fragment, C3d, was nearly identical to that of the wild-type FH19-20:C3d complex, consistent with mutants binding to C3b with wild-type-like affinity. The S1191L mutation enhanced thermal stability of module 20, whereas the V1197A mutation dramatically decreased it. Thus, although mutant proteins were folded at 37 °C, they differ in conformational rigidity. Neither single substitutions nor double substitutions increased measurably the extent of FH19-20 self-association, nor did these mutations significantly affect the affinity of FH19-20 for three glycosaminoglycans, despite critical roles of module 20 in recognizing polyanionic self-surface markers. Unexpectedly, FH19-20 mutants containing Leu1191 self-associated on a heparin-coated surface to a higher degree than on surfaces coated with dermatan or chondroitin sulfates. Thus, potentially disease-related functional distinctions between mutants, and between FH and FH-related 1, may manifest in the presence of specific glycosaminoglycans.
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Affiliation(s)
- Andrew P Herbert
- Edinburgh Biomolecular NMR Unit, EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, UK
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20
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Morgan HP, Jiang J, Herbert AP, Kavanagh D, Uhrin D, Barlow PN, Hannan JP. Crystallographic determination of the disease-associated T1184R variant of complement regulator factor H. Acta Crystallogr D Biol Crystallogr 2011; 67:593-600. [PMID: 21697597 DOI: 10.1107/s0907444911015423] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 04/24/2011] [Indexed: 11/10/2022]
Abstract
The soluble 155 kDa glycoprotein factor H (FH) protects host tissue from damage by the human complement system. It accelerates decay of the alternative-pathway C3 convertase, C3bBb, and is a cofactor for factor I-mediated cleavage of the opsonin C3b. Numerous mutations and single-nucleotide polymorphisms (SNPs) occur in the gene encoding FH and the resulting missense mutations and truncation products result in altered functionality that predisposes to the development of the serious renal condition atypical haemolytic uraemic syndrome (aHUS). Other polymorphisms are linked to membranoproliferative glomerulonephritis and macular degeneration. The two C-terminal modules of FH (FH19-20) harbour numerous aHUS-associated mutations that disrupt the ability of factor H to protect host cells from complement-mediated damage. In this work, the crystal structure of an aHUS-associated T1184R variant of FH19-20 at a resolution of 1.52 Å is described. It is shown that this mutation has negligible structural effects but causes a significant change in the electrostatic surface of these two domains. Mechanisms are discussed by which this mutation may alter FH-ligand interactions, particularly with regard to the extension of a region of this molecule within module 20 that has been associated with the binding of glycosaminoglycans (GAGs) or sialic acid residues.
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Affiliation(s)
- Hugh P Morgan
- Institute of Structural and Molecular Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Scotland
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21
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Morgan HP, Schmidt CQ, Guariento M, Blaum BS, Gillespie D, Herbert AP, Kavanagh D, Mertens HDT, Svergun DI, Johansson CM, Uhrín D, Barlow PN, Hannan JP. Structural basis for engagement by complement factor H of C3b on a self surface. Nat Struct Mol Biol 2011; 18:463-70. [PMID: 21317894 PMCID: PMC3512577 DOI: 10.1038/nsmb.2018] [Citation(s) in RCA: 195] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 01/14/2011] [Indexed: 12/15/2022]
Abstract
Complement factor H (FH) attenuates C3b molecules tethered via their thioester domains to self-surfaces and thereby protects host tissues. FH is a cofactor for initial C3b proteolysis that ultimately yields a surface-attached fragment (C3d), corresponding to the thioester domain. We used NMR and X-ray crystallography to study the C3d:FH19–20 complex in atomic detail. NMR further identified glycosaminoglycan-binding residues in FH module 20 of the C3d:FH19–20 complex. Mutagenesis justified the merging of the C3d:FH19–20 structure with an existing C3b:FH1–4 crystal structure. The merged structure was concatenated with the available FH6–8 crystal structure and new SAXS-derived FH1–4, FH8–15 and FH15–19 envelopes. The combined data suggests a bent-back FH molecule, binding via its termini to two sites on one C3b molecule and simultaneously to adjacent polyanionic host-surface markers.
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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, UK
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22
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Blaum BS, Deakin JA, Johansson CM, Herbert AP, Barlow PN, Lyon M, Uhrín D. Lysine and arginine side chains in glycosaminoglycan-protein complexes investigated by NMR, cross-linking, and mass spectrometry: a case study of the factor H-heparin interaction. J Am Chem Soc 2010; 132:6374-81. [PMID: 20394361 DOI: 10.1021/ja1000517] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We have used the interaction between module 7 of complement factor H (CFH approximately 7) and a fully sulfated heparin tetrasaccharide to exemplify a new approach for studying contributions of basic side chains to the formation of glycosaminoglycan (GAG)-protein complexes. We first employed HISQC and H(2)CN NMR experiments to monitor the side-chain resonances of lysines and arginines in (15)N, (13)C-labeled protein during titrations with a fully sulfated heparin tetrasaccharide under physiological conditions. Under identical conditions and using (15)N-labeled protein, we then cross-linked tetrasaccharide to CFH approximately 7 and confirmed the 1:1 stoichiometry by FT-ICR-MS. We subsequently characterized this covalent protein-GAG conjugate by NMR and further MS techniques. MALDI-TOF MS identified protein fragments obtained via trypsin digestion or chemical fragmentation, yielding information concerning the site of GAG attachment. Combining MS and NMR data allowed us to identify the side chain of K405 as the point of attachment of the cross-linked heparin oligosaccharide to CFH approximately 7. On the basis of the analysis of NMR and MS data of the noncovalent and cross-linked CFH approximately 7-tetrasaccharide complexes, we conclude that the K446 side chain is not essential for binding the tetrasaccharide, despite the large chemical shift perturbations of its backbone amide (15)N and (1)H resonances during titrations. We show that R444 provides the most important charge-charge interaction within a C-terminal heparin-binding subsite of CFH approximately 7 whereas side chains of R404, K405, and K388 are the predominant contributors to an N-terminal binding subsite located in the immediate vicinity of residue 402, which is implicated in age-related macular degeneration (AMD).
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Affiliation(s)
- Bärbel S Blaum
- 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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23
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Pappworth IY, Denton M, Kavanagh D, Moore I, Strain L, Barlow PN, Herbert AP, Schmidt CQ. Factor H autoantibodies are associated with MPGN. Mol Immunol 2010. [DOI: 10.1016/j.molimm.2010.05.274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Martin M, Leffler J, Herbert AP, Norström E, Barlow PN, Blom AM. Ligands for C1q and factor H on the surface of apoptotic cells. Mol Immunol 2010. [DOI: 10.1016/j.molimm.2010.05.165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Lesher AM, Kimura Y, Gullipalli D, Zhou L, Herbert AP, Barlow P, Skerka C, Zipfel P, Miwa T, Song WC. Properdin is required for autologous tissue injury but not systemic complement consumption associated with uncontrolled alternative pathway activation. Mol Immunol 2010. [DOI: 10.1016/j.molimm.2010.05.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Dhillon B, Wright AF, Tufail A, Pappworth I, Hayward C, Moore I, Strain L, Kavanagh D, Barlow PN, Herbert AP, Schmidt CQ, Armbrecht AM, Laude A, Deary IJ, Staniforth SJ, Holmes LV, Goodship THJ, Marchbank KJ. Complement factor h autoantibodies and age-related macular degeneration. Invest Ophthalmol Vis Sci 2010; 51:5858-63. [PMID: 20592223 DOI: 10.1167/iovs.09-5124] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In this case-control study, the hypothesis that factor H autoantibodies are associated with age-related macular degeneration (AMD) was examined. METHODS One hundred AMD patients (median age, 78 years), 98 age-matched control subjects (median age, 78 years) known not to have AMD, and 100 healthy blood donors (median age, 43 years) were enrolled. An enzyme-linked immunosorbent assay (ELISA) was used to screen for complement factor H autoantibodies and either quantitative polymerase chain reaction (qPCR) or multiplex ligation-dependent probe amplification (MLPA) were performed to measure the copy number of the gene encoding complement factor H-related protein 3 (CFHR3). RESULTS There was a significant difference in the median complement factor H autoantibody titer between the three groups (AMD patients, 196 reference units [RU]]; age-match control subjects, 316 RU; and blood donor control subjects, 121 RU; Kruskal-Wallis test, P < 0.001). Pair-wise comparison (Mann-Whitney test) showed that all three groups were significantly different from each other. Two different thresholds were used in the healthy blood donors to identify individuals with complement factor H autoantibodies. Both suggested that the prevalence of factor H autoantibodies was decreased in AMD patients. The CFHR3 copy number was measured as a surrogate for the deletion of the genes encoding complement factor H-related proteins 3 and 1 (CFHR3/1). The allele frequency of the deletion was significantly higher in the age-matched control subjects than in the AMD patients (22.2% vs. 8.2%). CONCLUSIONS The level of factor H autoantibodies is lower in AMD patients than in age-matched control subjects.
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Affiliation(s)
- Baljean Dhillon
- Department of Clinical and Surgical Sciences, Princess Alexandra Eye Pavilion
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Leffler J, Herbert AP, Norström E, Schmidt CQ, Barlow PN, Blom AM, Martin M. Annexin-II, DNA, and histones serve as factor H ligands on the surface of apoptotic cells. J Biol Chem 2010; 285:3766-3776. [PMID: 19951950 PMCID: PMC2823518 DOI: 10.1074/jbc.m109.045427] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [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: 07/16/2009] [Revised: 11/10/2009] [Indexed: 12/22/2022] Open
Abstract
Apoptotic cells are opsonized by complement components such as C1q and C3b, which increases their susceptibility to phagocytosis. Soluble complement inhibitors such as factor H (fH) also recognize apoptotic cells to minimize the pro-inflammatory effects of downstream complement activation. We used four radiolabeled protein constructs that span different regions of the 20 complement control protein (CCP) modules that make up fH and found that fragments comprising CCPs 6-8, CCPs 8-15, and CCPs 19-20 but not CCPs 1-4, bound to apoptotic Jurkat T cells. There are four possible ligand types on apoptotic cells that could recruit fH: proteins, carbohydrates, lipids, and DNA. We found that CCPs 6-8 of fH bind to annexin-II, a trypsin-insensitive protein that becomes exposed on surfaces of apoptotic cells. The second ligand of fH, which interacts with CCPs 6-8 and 19-20, is DNA. Confocal microscopy showed co-localization of fH with antibodies specific for DNA. fH also binds to histones devoid of DNA, and CCPs 1-4, 6-8, and 8-15 mediate this interaction. Treatment of apoptotic cells with neuraminidase, chondroitinase, heparitinase, and heparinase did not change fH binding. Treatment of apoptotic cells with phospholipase A(2) dramatically increased both binding of fH and cell-surface DNA. We also excluded the possibility that fH interacts with lysophospholipids using surface plasmon resonance and flow cytometry with lipid-coated beads. Identification of annexin-II as one of the fH ligands on apoptotic cells together with the fact that autoantibodies against annexin-II are found in systemic lupus erythematosus provides further insight into understanding the pathogenesis of this disease.
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Affiliation(s)
- Jonatan Leffler
- From the Department of Laboratory Medicine, Wallenberg Laboratory, University Hospital Malmö, Lund University, S-205 02 Malmö, Sweden and
| | - Andrew P Herbert
- the Edinburgh Biological NMR Unit, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, United Kingdom
| | - Eva Norström
- From the Department of Laboratory Medicine, Wallenberg Laboratory, University Hospital Malmö, Lund University, S-205 02 Malmö, Sweden and
| | - Christoph Q Schmidt
- the Edinburgh Biological NMR Unit, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, United Kingdom
| | - Paul N Barlow
- the Edinburgh Biological NMR Unit, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, United Kingdom
| | - Anna M Blom
- From the Department of Laboratory Medicine, Wallenberg Laboratory, University Hospital Malmö, Lund University, S-205 02 Malmö, Sweden and.
| | - Myriam Martin
- From the Department of Laboratory Medicine, Wallenberg Laboratory, University Hospital Malmö, Lund University, S-205 02 Malmö, Sweden and
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Serfiotis-Mitsa D, Herbert AP, Roberts GA, Soares DC, White JH, Blakely GW, Uhrín D, Dryden DTF. The structure of the KlcA and ArdB proteins reveals a novel fold and antirestriction activity against Type I DNA restriction systems in vivo but not in vitro. Nucleic Acids Res 2009; 38:1723-37. [PMID: 20007596 PMCID: PMC2836571 DOI: 10.1093/nar/gkp1144] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Plasmids, conjugative transposons and phage frequently encode anti-restriction proteins to enhance their chances of entering a new bacterial host that is highly likely to contain a Type I DNA restriction and modification (RM) system. The RM system usually destroys the invading DNA. Some of the anti-restriction proteins are DNA mimics and bind to the RM enzyme to prevent it binding to DNA. In this article, we characterize ArdB anti-restriction proteins and their close homologues, the KlcA proteins from a range of mobile genetic elements; including an ArdB encoded on a pathogenicity island from uropathogenic Escherichia coli and a KlcA from an IncP-1b plasmid, pBP136 isolated from Bordetella pertussis. We show that all the ArdB and KlcA act as anti-restriction proteins and inhibit the four main families of Type I RM systems in vivo, but fail to block the restriction endonuclease activity of the archetypal Type I RM enzyme, EcoKI, in vitro indicating that the action of ArdB is indirect and very different from that of the DNA mimics. We also present the structure determined by NMR spectroscopy of the pBP136 KlcA protein. The structure shows a novel protein fold and it is clearly not a DNA structural mimic.
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Affiliation(s)
- Dimitra Serfiotis-Mitsa
- EaStChem School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3JJ, UK
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Schmidt CQ, Herbert AP, Makou E, Matis I, Mertens HD, Svergun DI, Rowe A, Barlow PN. Compact structure of the central portion of factor H. Mol Immunol 2009. [DOI: 10.1016/j.molimm.2009.05.321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Ricklin D, Tzekou A, Garcia BL, Hammel M, McWhorter WJ, Sfyroera G, Wu YQ, Holers VM, Herbert AP, Barlow PN, Geisbrecht BV, Lambris JD. A molecular insight into complement evasion by the staphylococcal complement inhibitor protein family. J Immunol 2009; 183:2565-74. [PMID: 19625656 DOI: 10.4049/jimmunol.0901443] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Staphylococcus aureus possesses an impressive arsenal of complement evasion proteins that help the bacterium escape attack of the immune system. The staphylococcal complement inhibitor (SCIN) protein exhibits a particularly high potency and was previously shown to block complement by acting at the level of the C3 convertases. However, many details about the exact binding and inhibitory mechanism remained unclear. In this study, we demonstrate that SCIN directly binds with nanomolar affinity to a functionally important area of C3b that lies near the C terminus of its beta-chain. Direct competition of SCIN with factor B for C3b slightly decreased the formation of surface-bound convertase. However, the main inhibitory effect can be attributed to an entrapment of the assembled convertase in an inactive state. Whereas native C3 is still able to bind to the blocked convertase, no generation and deposition of C3b could be detected in the presence of SCIN. Furthermore, SCIN strongly competes with the binding of factor H to C3b and influences its regulatory activities: the SCIN-stabilized convertase was essentially insensitive to decay acceleration by factor H and the factor I- and H-mediated conversion of surface-bound C3b to iC3b was significantly reduced. By targeting a key area on C3b, SCIN is able to block several essential functions within the alternative pathway, which explains the high potency of the inhibitor. Our findings provide an important insight into complement evasion strategies by S. aureus and may act as a base for further functional studies.
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Affiliation(s)
- Daniel Ricklin
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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31
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Ferreira VP, Herbert AP, Cortés C, McKee KA, Blaum BS, Esswein ST, Uhrín D, Barlow PN, Pangburn MK, Kavanagh D. The binding of factor H to a complex of physiological polyanions and C3b on cells is impaired in atypical hemolytic uremic syndrome. J Immunol 2009; 182:7009-18. [PMID: 19454698 DOI: 10.4049/jimmunol.0804031] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Factor H (fH) is essential for complement homeostasis in fluid-phase and on surfaces. Its two C-terminal domains (CCP 19-20) anchor fH to self-surfaces where it prevents C3b amplification in a process requiring its N-terminal four domains. In atypical hemolytic uremic syndrome (aHUS), mutations clustering toward the C terminus of fH may disrupt interactions with surface-associated C3b or polyanions and thereby diminish the ability of fH to regulate complement. To test this, we compared a recombinant protein encompassing CCP 19-20 with 16 mutants. The mutations had only very limited and localized effects on protein structure. Although we found four aHUS-linked fH mutations that decreased binding to C3b and/or to heparin (a model compound for cell surface polyanionic carbohydrates), we identified five aHUS-associated mutants with increased affinity for either or both ligands. Strikingly, these variable affinities for the individual ligands did not correlate with the extent to which all the aHUS-associated mutants were found to be impaired in a more physiological assay that measured their ability to inhibit cell surface complement functions of full-length fH. Taken together, our data suggest that disruption of a complex fH-self-surface recognition process, involving a balance of affinities for protein and physiological carbohydrate ligands, predisposes to aHUS.
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Affiliation(s)
- Viviana P Ferreira
- Department of Biochemistry, Center for Biomedical Research, University of Texas Health Science Center, Tyler, TX 75708, USA
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32
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Phelan MM, Thai CT, Herbert AP, Bella J, Uhrín D, Ogata RT, Barlow PN, Bramham J. 1H, 15N and 13C resonance assignment of the pair of Factor-I like modules of the complement protein C7. Biomol NMR Assign 2009; 3:49-52. [PMID: 19636945 DOI: 10.1007/s12104-008-9139-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 12/19/2008] [Indexed: 05/28/2023]
Abstract
The carboxy terminus of human complement component C7 comprises two Factor I-like Modules (FIMs) which are essential for formation of the Membrane Attack Complex, the terminal pathway of the innate immune system. C7-FIMs is a 16.9 kDa, recombinant, disulphide-rich, protein encompassing this C-terminal domain. Using conventional triple resonance experiments 93% of the (1)H, (15)N and (13)C assignment has been achieved, accounting for all assignment apart from a flexible N-terminus cloning artefact and an undefined loop. The chemical shifts have been deposited in the BioMagResBank; Accession No. 15996.
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Affiliation(s)
- Marie M Phelan
- Edinburgh Biomolecular NMR Unit, Joseph Black Building, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, Scotland, UK.
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Okroj M, Jenkins HT, Herbert AP, Barlow PN, Blom AM. Structural basis and functional effects of the interaction between complement inhibitor C4b-binding protein and DNA. Mol Immunol 2008; 46:62-9. [DOI: 10.1016/j.molimm.2008.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Accepted: 07/06/2008] [Indexed: 10/21/2022]
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Schmidt CQ, Herbert AP, Kavanagh D, Gandy C, Fenton CJ, Blaum BS, Lyon M, Uhrín D, Barlow PN. A new map of glycosaminoglycan and C3b binding sites on factor H. J Immunol 2008; 181:2610-9. [PMID: 18684951 DOI: 10.4049/jimmunol.181.4.2610] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human complement factor H, consisting of 20 complement control protein (CCP) modules, is an abundant plasma glycoprotein. It prevents C3b amplification on self surfaces bearing certain polyanionic carbohydrates, while complement activation progresses on most other, mainly foreign, surfaces. Herein, locations of binding sites for polyanions and C3b are reexamined rigorously by overexpressing factor H segments, structural validation, and binding assays. As anticipated, constructs corresponding to CCPs 7-8 and 19-20 bind well in heparin-affinity chromatography. However, CCPs 8-9, previously reported to bind glycosaminoglycans, bind neither to heparin resin nor to heparin fragments in gel-mobility shift assays. Introduction of nonnative residues N-terminal to a construct containing CCPs 8-9, identical to those in proteins used in the previous report, converted this module pair to an artificially heparin-binding one. The module pair CCPs 12-13 does not bind heparin appreciably, notwithstanding previous suggestions to the contrary. We further checked CCPs 10-12, 11-14, 13-15, 10-15, and 8-15 for ability to bind heparin but found very low affinity or none. As expected, constructs corresponding to CCPs 1-4 and 19-20 bind C3b amine coupled to a CM5 chip (K(d)s of 14 and 3.5 microM, respectively) or a C1 chip (K(d)s of 10 and 4.5 microM, respectively). Constructs CCPs 7-8 and 6-8 exhibit measurable affinities for C3b according to surface plasmon resonance, although they are weak compared with CCPs 19-20. Contrary to expectations, none of several constructs encompassing modules from CCP 9 to 15 exhibited significant C3b binding in this assay. Thus, we propose a new functional map of factor H.
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Affiliation(s)
- Christoph Q Schmidt
- Schools of Biological Sciences and Chemistry, University of Edinburgh, Edinburgh, UK
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35
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Schmidt CQ, Herbert AP, Hocking HG, Uhrín D, Barlow PN. Translational mini-review series on complement factor H: structural and functional correlations for factor H. Clin Exp Immunol 2008; 151:14-24. [PMID: 18081691 DOI: 10.1111/j.1365-2249.2007.03553.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The 155-kDa glycoprotein, complement factor H (CFH), is a regulator of complement activation that is abundant in human plasma. Three-dimensional structures of over half the 20 complement control protein (CCP) modules in CFH have been solved in the context of single-, double- and triple-module segments. Proven binding sites for C3b occupy the N and C termini of this elongated molecule and may be brought together by a bend in CFH mediated by its central CCP modules. The C-terminal CCP 20 is key to the ability of the molecule to adhere to polyanionic markers on self-surfaces where CFH acts to regulate amplification of the alternative pathway of complement. The surface patch on CCP 20 that binds to model glycosaminoglycans has been mapped using nuclear magnetic resonance (NMR), as has a second glycosaminoglycan-binding patch on CCP 7. These patches include many of the residue positions at which sequence variations have been linked to three complement-mediated disorders: dense deposit disease, age-related macular degeneration and atypical haemolytic uraemic syndrome. In one plausible model, CCP 20 anchors CFH to self-surfaces via a C3b/polyanion composite binding site, CCP 7 acts as a 'proof-reader' to help discriminate self- from non-self patterns of sulphation, and CCPs 1-4 disrupt C3/C5 convertase formation and stability.
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Affiliation(s)
- C Q Schmidt
- The Edinburgh Biomolecular NMR Unit, Schools of Chemistry and Biological Sciences, University of Edinburgh, Edinburgh, UK
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36
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Hocking HG, Herbert AP, Kavanagh D, Soares DC, Ferreira VP, Pangburn MK, Uhrín D, Barlow PN. Structure of the N-terminal region of complement factor H and conformational implications of disease-linked sequence variations. J Biol Chem 2008; 283:9475-87. [PMID: 18252712 PMCID: PMC2276370 DOI: 10.1074/jbc.m709587200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Factor H is a regulatory glycoprotein of the complement system. We expressed the three N-terminal complement control protein modules of human factor H (FH1-3) and confirmed FH1-3 to be the minimal unit with cofactor activity for C3b proteolysis by factor I. We reconstructed FH1-3 from NMR-derived structures of FH1-2 and FH2-3 revealing an ∼105-Å-long rod-like arrangement of the modules. In structural comparisons with other C3b-engaging proteins, factor H module 3 most closely resembles factor B module 3, consistent with factor H competing with factor B for binding C3b. Factor H modules 1, 2, and 3 each has a similar backbone structure to first, second, and third modules, respectively, of functional sites in decay accelerating factor and complement receptor type 1; the equivalent intermodular tilt and twist angles are also broadly similar. Resemblance between molecular surfaces is closest for first modules but absent in the case of second modules. Substitution of buried Val-62 with Ile (a factor H single nucleotide polymorphism potentially protective for age-related macular degeneration and dense deposit disease) causes rearrangements within the module 1 core and increases thermal stability but does not disturb the interface with module 2. Replacement of partially exposed (in module 1) Arg-53 by His (an atypical hemolytic uremic syndrome-linked mutation) did not impair structural integrity at 37 °C, but this FH1-2 mutant was less stable at higher temperatures; furthermore, chemical shift differences indicated potential for small structural changes at the module 1-2 interface.
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Affiliation(s)
- Henry G Hocking
- Edinburgh Biomolecular NMR Unit, Schools of Chemistry and Biological Sciences, Joseph Black Chemistry Bldg., University of Edinburgh, West Mains Road, Edinburgh, United Kingdom
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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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Schmidt CQ, Blaum BS, Herbert AP, Ferreira V, Pangburn MK, Uhrin D, Barlow PN. Unravelling the complexities of factor H action on self-surfaces. Mol Immunol 2007. [DOI: 10.1016/j.molimm.2007.06.204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hannan JP, Young KA, Herbert AP, Chen XS, Barlow PN, Holers VM. Characterizing the complement receptor type 2 (CR2)–Epstein-Barr virus interaction: A site-directed mutagenesis and molecular docking approach. Mol Immunol 2007. [DOI: 10.1016/j.molimm.2007.06.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hocking HG, Kavanagh D, Herbert AP, Ferreira V, Pangburn MK, Uhrin D, Barlow PN. Structure of the complement regulatory N-terminal region of factor H: Implications for disease. Mol Immunol 2007. [DOI: 10.1016/j.molimm.2007.06.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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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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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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Jenkins HT, Herbert AP, Blom AM, Barlow PN. C4b-binding protein—Structural basis for interactions with DNA and glycosaminoglycans. Mol Immunol 2007. [DOI: 10.1016/j.molimm.2006.07.101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kask L, Jenkins HT, Herbert AP, Barlow PN. Determination of the solution structure of part of the binding site for C4b on C4b-binding protein by NMR. Mol Immunol 2007. [DOI: 10.1016/j.molimm.2006.07.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Herbert AP, Schmidt C, Egan C, Lyon M, Pangburn MK, Uhrin D, Barlow PN. The disease-linked Y402H substitution in factor H has no non-local structural effects but disrupts a binding patch on CCP 7. Mol Immunol 2007. [DOI: 10.1016/j.molimm.2006.07.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hocking HG, Herbert AP, Barlow PN. Structural studies of the regulatory region of factor H. Mol Immunol 2007. [DOI: 10.1016/j.molimm.2006.07.090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ferreira VP, Herbert AP, Hocking HG, Barlow PN, Pangburn MK. Critical role of the C-terminal domains of factor H in regulating complement activation at cell surfaces. J Immunol 2006; 177:6308-16. [PMID: 17056561 DOI: 10.4049/jimmunol.177.9.6308] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The plasma protein factor H primarily controls the activation of the alternative pathway of complement. The C-terminal of factor H is known to be involved in protection of host cells from complement attack. In the present study, we show that domains 19-20 alone are capable of discriminating between host-like and complement-activating cells. Furthermore, although factor H possesses three binding sites for C3b, binding to cell-bound C3b can be almost completely inhibited by the single site located in domains 19-20. All of the regulatory activities of factor H are expressed by the N-terminal four domains, but these activities toward cell-bound C3b are inhibited by isolated recombinant domains 19-20 (rH 19-20). Direct competition with the N-terminal site is unlikely to explain this because regulation of fluid phase C3b is unaffected by domains 19-20. Finally, we show that addition of isolated rH 19-20 to normal human serum leads to aggressive complement-mediated lysis of normally nonactivating sheep erythrocytes and moderate lysis of human erythrocytes, which possess membrane-bound regulators of complement. Taken together, the results highlight the importance of the cell surface protective functions exhibited by factor H compared with other complement regulatory proteins. The results may also explain why atypical hemolytic uremic syndrome patients with mutations affecting domains 19-20 can maintain complement homeostasis in plasma while their complement system attacks erythrocytes, platelets, endothelial cells, and kidney tissue.
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Affiliation(s)
- Viviana P Ferreira
- Department of Biochemistry, Center for Biomedical Research, University of Texas, Health Science Center, Tyler, TX 75708, USA
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Herbert AP, Uhrín D, Lyon M, Pangburn MK, Barlow PN. Disease-associated sequence variations congregate in a polyanion recognition patch on human factor H revealed in three-dimensional structure. J Biol Chem 2006; 281:16512-20. [PMID: 16533809 DOI: 10.1074/jbc.m513611200] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [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: 12/20/2022] Open
Abstract
Mutations and polymorphisms in the regulator of complement activation, factor H, have been linked to atypical hemolytic uremic syndrome (aHUS), membranoproliferative glomerulonephritis, and age-related macular degeneration. Many aHUS patients carry mutations in the two C-terminal modules of factor H, which normally confer upon this abundant 155-kDa plasma glycoprotein its ability to selectively bind self-surfaces and prevent them from inappropriately triggering the complement cascade via the alternative pathway. In the current study, the three-dimensional solution structure of the C-terminal module pair of factor H has been determined. A binding site for a fully sulfated heparin-derived tetrasaccharide has been delineated using chemical shift mapping and the C3d/C3b-binding site inferred from sequence comparisons and computational docking. The resultant information allows assessment of the likely consequences of aHUS-associated amino acid substitutions in this critical region of factor H. It is striking that, excepting those likely to perturb the three-dimensional structure, aHUS-associated missense mutations congregate in the polyanion-binding site delineated in this study, thus potentially disrupting a vital mechanism for control of complement on self-surfaces in the microvasculature of the kidney. It is intriguing that a single nucleotide polymorphism predisposing to age-related macular degeneration occupies another region of factor H that harbors a polyanion-binding site.
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Affiliation(s)
- Andrew P Herbert
- Edinburgh Biomolecular NMR Unit, University of Edinburgh, West mains Road, Edinburgh EH9 3JJ, United Kingdom
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Brook E, Herbert AP, Jenkins HT, Soares DC, Barlow PN. Opportunities for New Therapies Based on the Natural Regulators of Complement Activation. Ann N Y Acad Sci 2005; 1056:176-88. [PMID: 16387686 DOI: 10.1196/annals.1352.033] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
While the complement system is an essential component of immunity, shutting down all or part of it could be beneficial in a wide range of clinical situations. Designer, small-molecule, protease inhibitors and antagonists of protein-protein interactions are under development, while an approach based on a humanized monoclonal antibody to the C5 component works effectively against the later stages of complement activation and is close to completing clinical trials. The cobra venom factor depletes plasma of essential complement components, and a humanized (nonimmunogenic) version is being sought. Perhaps the most promising approach to comprehensive complement downregulation, however, is the exploitation of innate regulators of complement activation, with two products in clinical trials. The potential for more efficacious complement blockers of this kind is growing because of better targeting, but a deeper knowledge at the atomic level of mechanisms of action of these regulators is needed to underpin a rational approach to design of still more potent complement inhibitors.
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Affiliation(s)
- Eve Brook
- Edinburgh Biomolecular NMR Unit, School of Chemistry, University of Edinburgh, Edinburgh, UK
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Herbert AP. The cytopathology of benign breast disease: criteria for diagnosis and an assessment of accuracy. Br J Clin Pract Suppl 1989; 68:11-6; discussion 23-5. [PMID: 2488551] [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] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- A P Herbert
- Department of Histopathology, Southampton General Hospital, UK
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