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Iatropoulos P, Noris M, Mele C, Piras R, Valoti E, Bresin E, Curreri M, Mondo E, Zito A, Gamba S, Bettoni S, Murer L, Fremeaux-Bacchi V, Vivarelli M, Emma F, Daina E, Remuzzi G. Complement gene variants determine the risk of immunoglobulin-associated MPGN and C3 glomerulopathy and predict long-term renal outcome. Mol Immunol 2016; 71:131-142. [DOI: 10.1016/j.molimm.2016.01.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/21/2016] [Accepted: 01/23/2016] [Indexed: 01/13/2023]
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52
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Bettoni S, Bresin E, Remuzzi G, Noris M, Donadelli R. Insights into the Effects of Complement Factor H on the Assembly and Decay of the Alternative Pathway C3 Proconvertase and C3 Convertase. J Biol Chem 2016; 291:8214-30. [PMID: 26903516 DOI: 10.1074/jbc.m115.693119] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Indexed: 12/12/2022] Open
Abstract
The activated fragment of C3 (C3b) and factor B form the C3 proconvertase (C3bB), which is cleaved by factor D to C3 convertase (C3bBb). Older studies (Conrad, D. H., Carlo, J. R., and Ruddy, S. (1978)J. Exp. Med.147, 1792-1805; Pangburn, M. K., and Müller-Eberhard, H. J. (1978)Proc. Natl. Acad. Sci. U.S.A.75, 2416-2420; Kazatchkine, M. D., Fearon, D. T., and Austen, K. F. (1979)J. Immunol.122, 75-81) indicated that the complement alternative pathway regulator factor H (FH) competes with factor B for C3b binding; however, the capability of FH to prevent C3bB assembly has not been formally investigated. Moreover, in the few published studies FH did not favor C3bB dissociation. Whether FH may affect C3bBb formation from C3bB is unknown. We set up user-friendly assays based on combined microplate/Western blotting techniques that specifically detect either C3bB or C3bBb, with the aim of investigating the effect of FH on C3bB assembly and decay and C3bBb formation and decay. We document that FH does not affect C3bB assembly, indicating that FH does not efficiently compete with factor B for C3b binding. We also found that FH does not dissociate C3bB. FH showed a strong C3bBb decay-accelerating activity, as reported previously, and also exerted an apparent inhibitory effect on C3bBb formation. The latter effect was not fully attributable to a rapid FH-mediated dissociation of C3bBb complexes, because blocking decay with properdin and C3 nephritic factor did not restore C3bBb formation. FH almost completely prevented release of the smaller cleavage subunit of FB (Ba), without modifying the amount of C3bB complexes, suggesting that FH inhibits the conversion of C3bB to C3bBb. Thus, the inhibitory effect of FH on C3bBb formation is likely the sum of inhibition of C3bB conversion to C3bBb and of C3bBb decay acceleration. Further studies are required to confirm these findings in physiological cell-based settings.
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Affiliation(s)
- Serena Bettoni
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo
| | - Elena Bresin
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo
| | - Giuseppe Remuzzi
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo, the Azienda Ospedaliera Papa Giovanni XXIII, Unit of Nephrology and Dialysis, 24127 Bergamo, and the Department of Biomedical and Clinical Sciences, University of Milan, 20157 Milan, Italy
| | - Marina Noris
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo,
| | - Roberta Donadelli
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo
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53
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Genetic variations in complement factors in patients with congenital thrombotic thrombocytopenic purpura with renal insufficiency. Int J Hematol 2016; 103:283-91. [DOI: 10.1007/s12185-015-1933-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/10/2015] [Accepted: 12/28/2015] [Indexed: 12/11/2022]
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54
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Nichols EM, Barbour TD, Pappworth IY, Wong EKS, Palmer JM, Sheerin NS, Pickering MC, Marchbank KJ. An extended mini-complement factor H molecule ameliorates experimental C3 glomerulopathy. Kidney Int 2015. [PMID: 26221753 PMCID: PMC4650264 DOI: 10.1038/ki.2015.233] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abnormal regulation of the complement alternative pathway is associated with C3 glomerulopathy. Complement factor H is the main plasma regulator of the alternative pathway and consists of 20 short consensus repeat (SCR) domains. Although recombinant full-length factor H represents a logical treatment for C3 glomerulopathy, its production has proved challenging. We and others have designed recombinant mini-factor H proteins in which ‘non-essential' SCR domains have been removed. Here, we report the in vitro and in vivo effects of a mini-complement factor H protein, FH1–5^18–20, using the unique factor H–deficient (Cfh−/−) mouse model of C3 glomerulopathy. FH1–5^18–20 is comprised of the key complement regulatory domains (SCRs 1–5) linked to the surface recognition domains (SCRs 18–20). Intraperitoneal injection of FH1–5^18–20 in Cfh−/− mice reduced abnormal glomerular C3 deposition, similar to full-length factor H. Systemic effects on plasma alternative pathway control were comparatively modest, in association with a short half-life. Thus, FH1–5^18–20 is a potential therapeutic agent for C3 glomerulopathy and other renal conditions with alternative pathway-mediated tissue injury.
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Affiliation(s)
- Eva-Maria Nichols
- Institutes of Cellular and Genetic Medicine, School of Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Thomas D Barbour
- Centre for Complement and Inflammation Research, Imperial College London, London, UK
| | - Isabel Y Pappworth
- Institutes of Cellular and Genetic Medicine, School of Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Edwin K S Wong
- Institutes of Cellular and Genetic Medicine, School of Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Jeremy M Palmer
- Institutes of Cellular and Genetic Medicine, School of Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Neil S Sheerin
- Institutes of Cellular and Genetic Medicine, School of Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Imperial College London, London, UK
| | - Kevin J Marchbank
- Institutes of Cellular and Genetic Medicine, School of Medicine, Newcastle University, Newcastle upon Tyne, UK
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55
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Ma L, Li Z, Liu K, Rong SS, Brelen ME, Young AL, Kumaramanickavel G, Pang CP, Chen H, Chen LJ. Association of Genetic Variants with Polypoidal Choroidal Vasculopathy: A Systematic Review and Updated Meta-analysis. Ophthalmology 2015; 122:1854-65. [PMID: 26081444 DOI: 10.1016/j.ophtha.2015.05.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 05/11/2015] [Accepted: 05/11/2015] [Indexed: 01/10/2023] Open
Abstract
TOPIC A systematic review and meta-analysis of the genetic association with polypoidal choroidal vasculopathy (PCV) and the genetic difference between PCV and neovascular age-related macular degeneration (nAMD). CLINICAL RELEVANCE To identify genetic biomarkers that are potentially useful for genetic diagnosis of PCV and for differentiating PCV from nAMD. METHODS We performed a literature search in EMBASE, PubMed, Web of Science, and the Chinese Biomedical Database for PCV genetic studies published before February 6, 2015. We then conducted a meta-analysis of all polymorphisms that had sufficient genotype/allele data reported in ≥2 studies and estimated the summary odds ratio (OR) and 95% confidence intervals (CIs) for PCV. We also compared the association profiles between PCV and nAMD, and performed a sensitivity analysis. RESULTS A total of 66 studies were included in the meta-analysis, involving 56 polymorphisms in 19 genes/loci. In total, 31 polymorphisms in 10 genes/loci (age-related maculopathy susceptibility 2 [ARMS2], high-temperature requirement factor A1 [HTRA1], complement factor H [CFH], complement component 2 [C2], CFB, RDBP, SKIV2L, CETP, 8p21, and 4q12) were significantly associated with PCV. Another 25 polymorphisms in 13 genes (ARMS2, HTRA1, C2, CFB, ELN, LIPC, LPL, ABCA1, VEGF-A, TLR3, LOXL1, SERPING1, and PEDF) had no significant association. Twelve polymorphisms at the ARMS2-HTRA1 locus showed significant differences between PCV and nAMD. The sensitivity analysis validated the significance of our analysis. CONCLUSIONS This study revealed 31 polymorphisms in 10 genes/loci that contribute to PCV susceptibility. Among them, ARMS2-HTRA1 also showed allelic diversity between PCV and nAMD. Our results confirm the gene variants that could affect the phenotypic expressions of PCV and nAMD.
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Affiliation(s)
- Li Ma
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Zhen Li
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Ke Liu
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China; Shenzhen Eye Hospital, Shenzhen, China
| | - Shi Song Rong
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Marten E Brelen
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China; Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Alvin L Young
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China; Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | | | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China; Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China; Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Haoyu Chen
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Li Jia Chen
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China; Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China; Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China.
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56
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Martínez-Barricarte R, Heurich M, López-Perrote A, Tortajada A, Pinto S, López-Trascasa M, Sánchez-Corral P, Morgan BP, Llorca O, Harris CL, Rodríguez de Córdoba S. The molecular and structural bases for the association of complement C3 mutations with atypical hemolytic uremic syndrome. Mol Immunol 2015; 66:263-73. [PMID: 25879158 PMCID: PMC4503813 DOI: 10.1016/j.molimm.2015.03.248] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 03/18/2015] [Accepted: 03/24/2015] [Indexed: 01/28/2023]
Abstract
Mutations in C3 have been associated with aHUS and other glomerulopathies. aHUS-associated C3 mutants R592W, R161W, and I1157T impair regulation by MCP, but not by FH. EM analysis provides the structural basis for the functional impairment of the R161W and I1157T mutants. Data supports aHUS-associated C3 mutations selectively affect complement regulation on surfaces.
Atypical hemolytic uremic syndrome (aHUS) associates with complement dysregulation caused by mutations and polymorphisms in complement activators and regulators. However, the reasons why some mutations in complement proteins predispose to aHUS are poorly understood. Here, we have investigated the functional consequences of three aHUS-associated mutations in C3, R592W, R161W and I1157T. First, we provide evidence that penetrance and disease severity for these mutations is modulated by inheritance of documented “risk” haplotypes as has been observed with mutations in other complement genes. Next, we show that all three mutations markedly reduce the efficiency of factor I-mediated C3b cleavage when catalyzed by membrane cofactor protein (MCP), but not when catalyzed by factor H. Biacore analysis showed that each mutant C3b bound sMCP (recombinant soluble MCP; CD46) at reduced affinity, providing a molecular basis for its reduced cofactor activity. Lastly, we show by electron microscopy structural analysis a displacement of the TED domain from the MG ring in C3b in two of the C3 mutants that explains these defects in regulation. As a whole our data suggest that aHUS-associated mutations in C3 selectively affect regulation of complement on surfaces and provide a structural framework to predict the functional consequences of the C3 genetic variants found in patients.
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Affiliation(s)
- Rubén Martínez-Barricarte
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Meike Heurich
- Institute of Infection & Immunity, School of Medicine, Cardiff University Heath Park, Cardiff CF14 4XN, United Kingdom
| | | | - Agustin Tortajada
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Sheila Pinto
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Margarita López-Trascasa
- Unidad de Inmunología, Hospital Universitario La Paz-IdiPAZ, and Ciber de Enfermedades Raras. Paseo de la Castellana 261, 28046 Madrid, Spain
| | - Pilar Sánchez-Corral
- Unidad de Investigación, Hospital Universitario La Paz-IdiPAZ, and Ciber de Enfermedades Raras. Paseo de la Castellana 261, 28046 Madrid, Spain
| | - B Paul Morgan
- Institute of Infection & Immunity, School of Medicine, Cardiff University Heath Park, Cardiff CF14 4XN, United Kingdom
| | - Oscar Llorca
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Claire L Harris
- Institute of Infection & Immunity, School of Medicine, Cardiff University Heath Park, Cardiff CF14 4XN, United Kingdom
| | - Santiago Rodríguez de Córdoba
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain.
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57
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Age-related macular degeneration and the role of the complement system. Mol Immunol 2015; 67:43-50. [PMID: 25804937 DOI: 10.1016/j.molimm.2015.02.032] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 11/21/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of visual impairment. It is characterised by damage to a tissue complex composed of the retinal pigment epithelium, Bruch's membrane and choriocapillaris. In early AMD extracellular debris including drusen accumulates in Bruch's membrane and then in late AMD geographic atrophy and/or neovascularisation develop. Variants in genes encoding components of the alternative pathway of the complement cascade have a major influence on AMD risk, especially at the RCA locus on chromosome 1, which contains CFH and the CFHR genes. Immunohistochemical studies have demonstrated complement components in unaffected and AMD macular tissue. Whilst other factors, including oxidative stress, play important roles in AMD pathogenesis, evidence for the central role played by complement dysregulation is discussed in this review.
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58
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Giles JL, Choy E, van den Berg C, Morgan BP, Harris CL. Functional analysis of a complement polymorphism (rs17611) associated with rheumatoid arthritis. THE JOURNAL OF IMMUNOLOGY 2015; 194:3029-34. [PMID: 25725109 PMCID: PMC4367161 DOI: 10.4049/jimmunol.1402956] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Complement is implicated in the pathogenesis of rheumatoid arthritis (RA); elevated levels of complement activation products have been measured in plasma, synovial fluid, and synovial tissues of patients. Complement polymorphisms are associated with RA in genome-wide association studies. Coding-region polymorphisms may directly impact protein activity; indeed, we have shown that complement polymorphisms affecting a single amino acid change cause subtle changes in individual component function that in combination have dramatic effects on complement activity and disease risk. In this study, we explore the functional consequences of a single nucleotide polymorphism (SNP) (rs17611) encoding a V802I polymorphism in C5 and propose a mechanism for its link to RA pathology. Plasma levels of C5, C5a, and terminal complement complex were measured in healthy and RA donors and correlated to rs17611 polymorphic status. Impact of the SNP on C5 functionality was assessed. Plasma C5a levels were significantly increased and C5 levels significantly lower with higher copy number of the RA risk allele for rs17611, suggesting increased turnover of C5 V802. Functional assays using purified C5 variants revealed no significant differences in lytic activity, suggesting that increased C5 V802 turnover was not mediated by complement convertase enzymes. C5 is also cleaved in vivo by proteases; the C5 V802 variant was more sensitive to cleavage with elastase and the “C5a” generated was biologically active. We hypothesize that this SNP in C5 alters the rate at which elastase generates active C5a in rheumatoid joints, hence recruiting neutrophils to the site thus maintaining a state of inflammation in arthritic joints.
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Affiliation(s)
- Joanna L Giles
- Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom;
| | - Ernest Choy
- Cardiff Regional Experimental Arthritis Treatment and Evaluation Centre, Section of Rheumatology, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom; and
| | - Carmen van den Berg
- Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom
| | - B Paul Morgan
- Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom
| | - Claire L Harris
- Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom
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59
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Warwick A, Khandhadia S, Ennis S, Lotery A. Age-Related Macular Degeneration: A Disease of Systemic or Local Complement Dysregulation? J Clin Med 2014; 3:1234-57. [PMID: 26237601 PMCID: PMC4470180 DOI: 10.3390/jcm3041234] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 01/25/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in developed countries. The role of complement in the development of AMD is now well-established. While some studies show evidence of complement dysregulation within the eye, others have demonstrated elevated systemic complement activation in association with AMD. It is unclear which one is the primary driver of disease. This has important implications for designing novel complement-based AMD therapies. We present a summary of the current literature and suggest that intraocular rather than systemic modulation of complement may prove more effective.
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Affiliation(s)
- Alasdair Warwick
- Clinical Neurosciences Research Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
| | - Samir Khandhadia
- Eye Unit, University Southampton NHS Trust, Southampton SO16 6YD, UK.
| | - Sarah Ennis
- Genomic Informatics, Human Genetics & Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
| | - Andrew Lotery
- Clinical Neurosciences Research Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
- Eye Unit, University Southampton NHS Trust, Southampton SO16 6YD, UK.
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60
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Sansbury FH, Cordell HJ, Bingham C, Bromilow G, Nicholls A, Powell R, Shields B, Smyth L, Warwicker P, Strain L, Wilson V, Goodship JA, Goodship THJ, Turnpenny PD. Factors determining penetrance in familial atypical haemolytic uraemic syndrome. J Med Genet 2014; 51:756-64. [PMID: 25261570 DOI: 10.1136/jmedgenet-2014-102498] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Inherited abnormalities of complement are found in ∼60% of patients with atypical haemolytic uraemic syndrome (aHUS). Such abnormalities are not fully penetrant. In this study, we have estimated the penetrance of the disease in three families with a CFH mutation (c.3643C>G; p. Arg1215Gly) in whom a common lineage is probable. 25 individuals have been affected with aHUS with three peaks of incidence-early childhood (n=6), early adulthood (n=11) and late adulthood (n=8). Eighteen individuals who have not developed aHUS carry the mutation. METHODS We estimated penetrance at the ages of 4, 27, 60 and 70 years as both a binary and a survival trait using MLINK and Mendel. We genotyped susceptibility factors in CFH, CD46 and CFHR1 in affected and unaffected carriers. RESULTS AND CONCLUSIONS We found that the estimates of penetrance at the age of 4 years ranged from <0.01 to 0.10, at the age of 27 years from 0.16 to 0.29, at the age of 60 years from 0.39 to 0.51 and at the age of 70 years from 0.44 to 0.64. We found that the CFH haplotype on the allele not carrying the CFH mutation had a significant effect on disease penetrance. In this family, we did not find that the CD46 haplotypes had a significant effect on penetrance.
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Affiliation(s)
- Francis H Sansbury
- Peninsula Clinical Genetics Service, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK University of Exeter Medical School, University of Exeter, Exeter, UK Bristol Clinical Genetics Service, University Hospitals Bristol NHS Foundation Trust, Clinical Genetics, St. Michael's Hospital, Bristol, UK
| | - Heather J Cordell
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Coralie Bingham
- University of Exeter Medical School, University of Exeter, Exeter, UK Department of Renal Medicine, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Wonford), Exeter, UK
| | - Gilly Bromilow
- Peninsula Clinical Genetics Service, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK
| | - Anthony Nicholls
- Department of Renal Medicine, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Wonford), Exeter, UK
| | - Roy Powell
- Research Design Service South West, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Wonford), Exeter, UK
| | - Bev Shields
- University of Exeter Medical School, University of Exeter, Exeter, UK
| | - Lucy Smyth
- Department of Renal Medicine, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Wonford), Exeter, UK
| | - Paul Warwicker
- Lister Renal Units, East and North Hertfordshire NHS Trust, Stevenage, UK
| | - Lisa Strain
- Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Valerie Wilson
- Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Judith A Goodship
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | | | - Peter D Turnpenny
- Peninsula Clinical Genetics Service, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK University of Exeter Medical School, University of Exeter, Exeter, UK
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Horie-Inoue K, Inoue S. Genomic aspects of age-related macular degeneration. Biochem Biophys Res Commun 2014; 452:263-75. [PMID: 25111812 DOI: 10.1016/j.bbrc.2014.08.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 08/04/2014] [Indexed: 11/29/2022]
Abstract
Age-related macular degeneration (AMD) is a major late-onset posterior eye disease that causes central vision to deteriorate among elderly populations. The predominant lesion of AMD is the macula, at the interface between the outer retina and the inner choroid. Recent advances in genetics have revealed that inflammatory and angiogenic pathways play critical roles in the pathophysiology of AMD. Genome-wide association studies have identified ARMS2/HTRA1 and CFH as major AMD susceptibility genes. Genetic studies for AMD will contribute to the prevention of central vision loss, the development of new treatment, and the maintenance of quality of vision for productive aging.
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Affiliation(s)
- Kuniko Horie-Inoue
- Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan.
| | - Satoshi Inoue
- Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan; Department of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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62
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Kawa MP, Machalinska A, Roginska D, Machalinski B. Complement system in pathogenesis of AMD: dual player in degeneration and protection of retinal tissue. J Immunol Res 2014; 2014:483960. [PMID: 25276841 PMCID: PMC4168147 DOI: 10.1155/2014/483960] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/18/2014] [Accepted: 08/01/2014] [Indexed: 12/25/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness among the elderly, especially in Western countries. Although the prevalence, risk factors, and clinical course of the disease are well described, its pathogenesis is not entirely elucidated. AMD is associated with a variety of biochemical abnormalities, including complement components deposition in the retinal pigment epithelium-Bruch's membrane-choriocapillaris complex. Although the complement system (CS) is increasingly recognized as mediating important roles in retinal biology, its particular role in AMD pathogenesis has not been precisely defined. Unrestricted activation of the CS following injury may directly damage retinal tissue and recruit immune cells to the vicinity of active complement cascades, therefore detrimentally causing bystander damage to surrounding cells and tissues. On the other hand, recent evidence supports the notion that an active complement pathway is a necessity for the normal maintenance of the neurosensory retina. In this scenario, complement activation appears to have beneficial effect as it promotes cell survival and tissue remodeling by facilitating the rapid removal of dying cells and resulting cellular debris, thus demonstrating anti-inflammatory and neuroprotective activities. In this review, we discuss both the beneficial and detrimental roles of CS in degenerative retina, focusing on the diverse aspects of CS functions that may promote or inhibit macular disease.
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Affiliation(s)
- Milosz P. Kawa
- Department of General Pathology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
| | - Anna Machalinska
- Department of Ophthalmology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
- Department of Histology and Embryology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
| | - Dorota Roginska
- Department of General Pathology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
| | - Boguslaw Machalinski
- Department of General Pathology, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szczecin, Poland
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Abstract
Hemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. The atypical form of HUS is a disease characterized by complement overactivation. Inherited defects in complement genes and acquired autoantibodies against complement regulatory proteins have been described. Incomplete penetrance of mutations in all predisposing genes is reported, suggesting that a precipitating event or trigger is required to unmask the complement regulatory deficiency. The underlying genetic defect predicts the prognosis both in native kidneys and after renal transplantation. The successful trials of the complement inhibitor eculizumab in the treatment of atypical HUS will revolutionize disease management.
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Affiliation(s)
- David Kavanagh
- The Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
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64
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Yu Y, Triebwasser MP, Wong EKS, Schramm EC, Thomas B, Reynolds R, Mardis ER, Atkinson JP, Daly M, Raychaudhuri S, Kavanagh D, Seddon JM. Whole-exome sequencing identifies rare, functional CFH variants in families with macular degeneration. Hum Mol Genet 2014; 23:5283-93. [PMID: 24847005 DOI: 10.1093/hmg/ddu226] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
We sequenced the whole exome of 35 cases and 7 controls from 9 age-related macular degeneration (AMD) families in whom known common genetic risk alleles could not explain their high disease burden and/or their early-onset advanced disease. Two families harbored novel rare mutations in CFH (R53C and D90G). R53C segregates perfectly with AMD in 11 cases (heterozygous) and 1 elderly control (reference allele) (LOD = 5.07, P = 6.7 × 10(-7)). In an independent cohort, 4 out of 1676 cases but none of the 745 examined controls or 4300 NHBLI Exome Sequencing Project (ESP) samples carried the R53C mutation (P = 0.0039). In another family of six siblings, D90G similarly segregated with AMD in five cases and one control (LOD = 1.22, P = 0.009). No other sample in our large cohort or the ESP had this mutation. Functional studies demonstrated that R53C decreased the ability of FH to perform decay accelerating activity. D90G exhibited a decrease in cofactor-mediated inactivation. Both of these changes would lead to a loss of regulatory activity, resulting in excessive alternative pathway activation. This study represents an initial application of the whole-exome strategy to families with early-onset AMD. It successfully identified high impact alleles leading to clearer functional insight into AMD etiopathogenesis.
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Affiliation(s)
- Yi Yu
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA
| | - Michael P Triebwasser
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Edwin K S Wong
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne, UK
| | - Elizabeth C Schramm
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Brett Thomas
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Robyn Reynolds
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA
| | - Elaine R Mardis
- The Genome Institute at Washington University, Saint Louis, MO, USA
| | - John P Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Mark Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Soumya Raychaudhuri
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA Partners HealthCare Center for Personalized Genetic Medicine, Boston, MA, USA Division of Genetics, Brigham and Women's Hospital, Boston, MA, USA Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK
| | - David Kavanagh
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne, UK
| | - Johanna M Seddon
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA Department of Ophthalmology, Tufts University School of Medicine, Boston, MA, USA Sackler School of Graduate Medical Sciences, Tufts University, Boston, MA, USA
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Paixão-Cavalcante D, Torreira E, Lindorfer MA, Rodriguez de Cordoba S, Morgan BP, Taylor RP, Llorca O, Harris CL. A humanized antibody that regulates the alternative pathway convertase: potential for therapy of renal disease associated with nephritic factors. THE JOURNAL OF IMMUNOLOGY 2014; 192:4844-51. [PMID: 24729617 DOI: 10.4049/jimmunol.1303131] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dysregulation of the complement alternative pathway can cause disease in various organs that may be life-threatening. Severe alternative pathway dysregulation can be triggered by autoantibodies to the C3 convertase, termed nephritic factors, which cause pathological stabilization of the convertase enzyme and confer resistance to innate control mechanisms; unregulated complement consumption followed by deposition of C3 fragments in tissues ensues. The mAb, 3E7, and its humanized derivative, H17, have been shown previously to specifically bind activated C3 and prevent binding of both the activating protein, factor B, and the inhibitor, factor H, which are opposite effects that complicate its potential for therapy. Using ligand binding assays, functional assays, and electron microscopy, we show that these Abs bind C3b via a site that overlaps the binding site on C3 for the Ba domain within factor B, thereby blocking an interaction essential for convertase formation. Both Abs also bind the preformed convertase, C3bBb, and provide powerful inhibition of complement activation by preventing cleavage of C3. Critically, the Abs also bound and inhibited C3 cleavage by the nephritic factor-stabilized convertase. We suggest that by preventing enzyme formation and/or cleavage of C3 to its active downstream fragments, H17 may be an effective therapy for conditions caused by severe dysregulation of the C3 convertase and, in particular, those that involve nephritic factors, such as dense deposit disease.
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Affiliation(s)
- Danielle Paixão-Cavalcante
- Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom
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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] [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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Matsumiya W, Honda S, Yanagisawa S, Miki A, Nagai T, Tsukahara Y. Evaluation of clinical and genetic indicators for the early response to intravitreal ranibizumab in exudative age-related macular degeneration. Pharmacogenomics 2014; 15:833-43. [DOI: 10.2217/pgs.14.51] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Aim: This study was conducted to evaluate the possible clinical and genetic indicators for an early response to intravitreal ranibizumab (IVR) in exudative age-related macular degeneration (AMD). Patients & methods: The records of 120 eyes from 120 Japanese patients with treatment-naive exudative AMD were retrospectively reviewed. Three consecutive IVR treatments were performed every month. Achievement of anatomical resolution was evaluated by ophthalmoscopy and optical coherence tomography. Multivariable logistic regression analysis was conducted by analyzing SNPs in the ARMS2 locus (A69S) and in the CFH gene (I62V and Y402H), in addition to clinical factors. Results: The mean central retinal thickness of overall patients was significantly decreased (-120.1 ± 122.8 µm, p = 2.7 × 10-19) at 3 months after the initial treatment. In the logistic regression analysis, the poor anatomical resolution of the lesion at 3 months was associated with the combination of CFH I62V + CFH Y402H variants (p = 0.0021), and the polypoidal choroidal vasculopathy lesions (p = 0.044). Conclusion: The CFH variants and the polypoidal choroidal vasculopathy lesion may influence the early anatomical resolution with IVR in exudative AMD. Original submitted 30 September 2013; Revision submitted 13 March 2014
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Affiliation(s)
- Wataru Matsumiya
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Shigeru Honda
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Suiho Yanagisawa
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Akiko Miki
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Takayuki Nagai
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Yasutomo Tsukahara
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
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68
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Complement factor H and related proteins in age-related macular degeneration. C R Biol 2014; 337:178-84. [DOI: 10.1016/j.crvi.2013.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 12/03/2013] [Indexed: 12/17/2022]
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69
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Wang X, Geng P, Zhang Y, Zhang M. Association between complement factor H Val62Ile polymorphism and age-related macular degeneration susceptibility: a meta-analysis. Gene 2014; 538:306-12. [PMID: 24440287 DOI: 10.1016/j.gene.2014.01.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 10/12/2013] [Accepted: 01/08/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND An increasing body of studies has assessed the contribution of Val62Ile polymorphism to age-related macular degeneration (AMD) risk, but the exact association still remains uncertain. This meta-analysis was undertaken in order to further characterize the potential association between Val62Ile polymorphism and AMD risk in four different ethnic populations. METHODS A meta-analysis was performed using data available from 16 case-control studies evaluating correlation between the Val62Ile polymorphism and AMD in Caucasian, Chinese, Japanese and South Korean populations. Data extraction and study quality assessment were performed in duplicate. Summary odds ratios (ORs) and 95% confidence intervals (CIs) of allele contrast and genotype contrast were estimated using the random-effects model. The Q-statistic test was used to identify heterogeneity, and the funnel plot was adopted to evaluate publication bias. RESULTS Sixteen studies involving a total of 11,400 subjects based on the search criteria were included in the meta-analysis. In overall populations, the Val62Ile polymorphism seemed to be associated with AMD (ORAA vs. GG=0.40, 95% CI=0.28-0.59; ORAA+GA vs. GG=0.72, 95% CI=0.64-0.80; ORAA vs. GC+GG=0.50, 95% CI=0.36-0.70; ORA vs. G=0.68, 95% CI=0.58-0.78; ORGA vs. GG=0.71, 95% CI=0.65-0.77). Similarly, subgroup analysis also revealed that this polymorphism was related to AMD in all ethnicities. CONCLUSIONS This meta-analysis suggested that Val62Ile polymorphism was associated with susceptibility to AMD.
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Affiliation(s)
- Xin Wang
- Department of Ophthalmology, Chinese PLA General Hospital & Chinese PLA Medical School, 28 Fuxing Road, Beijing 100853, People's Republic of China; Department of Ophthalmology, The 306th Hospital of Chinese PLA, 9 North Anxiang Road, Beijing 100101, People's Republic of China
| | - Peiliang Geng
- Institute of Oncology, Key Laboratory of Oncology, Cancer Center, Division of Internal Medicine, Chinese PLA General Hospital & Chinese PLA Medical School, 28 Fuxing Road, Beijing 100853, People's Republic of China
| | - Ying Zhang
- Department of Ophthalmology, Chinese PLA General Hospital & Chinese PLA Medical School, 28 Fuxing Road, Beijing 100853, People's Republic of China
| | - Maonian Zhang
- Department of Ophthalmology, Chinese PLA General Hospital & Chinese PLA Medical School, 28 Fuxing Road, Beijing 100853, People's Republic of China.
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70
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Contreras AV, Zenteno JC, Fernández-López JC, Rodríguez-Corona U, Falfán-Valencia R, Sebastian L, Morales F, Ochoa-Contreras D, Carnevale A, Silva-Zolezzi I. CFH haplotypes and ARMS2, C2, C3, and CFB alleles show association with susceptibility to age-related macular degeneration in Mexicans. Mol Vis 2014; 20:105-16. [PMID: 24453474 PMCID: PMC3891434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 01/11/2014] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To evaluate the contribution of genetic variants of complement factor H (CFH), complement component 2 and 3 (C2 and C3), complement factor B (CFB), and age-related maculopathy susceptibility 2 (ARMS2) to age-related macular degeneration (AMD) risk in the Mexican Mestizo population. METHODS Analysis included 282 unrelated Mexican patients with advanced AMD, 205 healthy controls, and 280 population controls. Stereoscopic fundus images were graded on the Clinical Age-Related Maculopathy System (CARMS). We designed a resequencing strategy using primers with M13 adaptor for the 23 exons of the CFH gene in a subgroup of 96 individuals clinically evaluated: 48 AMD cases and 48 age- and sex-matched healthy controls. Single nucleotide polymorphisms (SNPs) in C3 (Arg80Gly and Pro292Leu), C2 (rs547154), CFB (Leu9His), and ARMS2 (Ala69Ser) were genotyped in all patients, healthy and population controls using TaqMan assay. RESULTS All evaluated individuals were Mexican Mestizos, and their genetic ancestry was validated using 224 ancestry informative markers and calculating F(st) values. The CFH resequencing revealed 19 SNPs and a common variant in the intron 2 splice acceptor site; three CFH haplotypes inferred from individual genotypes, showed significant differences between cases and controls. The risk alleles in C3 (rs1047286, odds ratio [OR]=2.48, 95% confidence interval [CI]=1.64-3.75, p=1.59E-05; rs2230199, OR=2.15, 95% CI=1.48-3.13, p=6.28E-05) and in ARMS2 (rs10490924, OR=3.09, 95% CI=2.48-3.86, p=5.42E-23) were strongly associated with risk of AMD. The protective effect of alleles in C2 (rs547154) and CFB (rs4151667) showed a trend but was not significantly associated after correction for multiple testing. CONCLUSIONS Our results show that ARMS2 and C3 are major contributors to advanced AMD in Mexican patients, while the contributions of CFH, C2, and CFB are minor to those of other populations, reveling significant ethnic differences in minor allele frequencies. We provide evidence that two specific common haplotypes in the CFH gene predispose individuals to AMD, while another may confer reduced risk of disease in this admixed population.
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Affiliation(s)
| | - Juan Carlos Zenteno
- Department of Genetics and Research Unit, Institute of Ophthalmology Conde de Valenciana, Mexico City, Mexico,Biochemistry Department, Faculty of Medicine, UNAM, Mexico City, Mexico
| | | | | | - Ramcés Falfán-Valencia
- Laboratorio HLA, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | | | - Fabiola Morales
- Instituto Nacional de Medicina Genómica. Mexico City, Mexico
| | - Daniel Ochoa-Contreras
- Asociación Para Evitar la Ceguera en México, Hospital “Dr. Luis Sánchez Bulnes,” Mexico City, Mexico
| | | | - Irma Silva-Zolezzi
- Nutrition and Health Department, Nestlé Research Center, Lausanne, Switzerland
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71
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Day AJ, Clark SJ, Bishop PN. Understanding the molecular basis of age-related macular degeneration and how the identification of new mechanisms may aid the development of novel therapies. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.11.10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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72
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Won J, Charette JR, Philip VM, Stearns TM, Zhang W, Naggert JK, Krebs MP, Nishina PM. Genetic modifier loci of mouse Mfrp(rd6) identified by quantitative trait locus analysis. Exp Eye Res 2013; 118:30-5. [PMID: 24200520 DOI: 10.1016/j.exer.2013.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/27/2013] [Indexed: 11/25/2022]
Abstract
The identification of genes that modify pathological ocular phenotypes in mouse models may improve our understanding of disease mechanisms and lead to new treatment strategies. Here, we identify modifier loci affecting photoreceptor cell loss in homozygous Mfrp(rd6) mice, which exhibit a slowly progressive photoreceptor degeneration. A cohort of 63 F2 homozygous Mfrp(rd6) mice from a (B6.C3Ga-Mfrp(rd6)/J × CAST/EiJ) F1 intercross exhibited a variable number of cell bodies in the retinal outer nuclear layer at 20 weeks of age. Mice were genotyped with a panel of single nucleotide polymorphism markers, and genotypes were correlated with phenotype by quantitative trait locus (QTL) analysis to map modifier loci. A genome-wide scan revealed a statistically significant, protective candidate locus on CAST/EiJ Chromosome 1 and suggestive modifier loci on Chromosomes 6 and 11. Multiple regression analysis of a three-QTL model indicated that the modifier loci on Chromosomes 1 and 6 together account for 26% of the observed phenotypic variation, while the modifier locus on Chromosome 11 explains only an additional 4%. Our findings indicate that the severity of the Mfrp(rd6) retinal degenerative phenotype in mice depends on the strain genetic background and that a significant modifier locus on CAST/EiJ Chromosome 1 protects against Mfrp(rd6)-associated photoreceptor loss.
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Affiliation(s)
- Jungyeon Won
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | | | - Vivek M Philip
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | | | - Weidong Zhang
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Jürgen K Naggert
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Mark P Krebs
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Patsy M Nishina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA.
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73
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Ansari M, McKeigue PM, Skerka C, Hayward C, Rudan I, Vitart V, Polasek O, Armbrecht AM, Yates JRW, Vatavuk Z, Bencic G, Kolcic I, Oostra BA, Van Duijn CM, Campbell S, Stanton CM, Huffman J, Shu X, Khan JC, Shahid H, Harding SP, Bishop PN, Deary IJ, Moore AT, Dhillon B, Rudan P, Zipfel PF, Sim RB, Hastie ND, Campbell H, Wright AF. Genetic influences on plasma CFH and CFHR1 concentrations and their role in susceptibility to age-related macular degeneration. Hum Mol Genet 2013; 22:4857-69. [PMID: 23873044 PMCID: PMC3820139 DOI: 10.1093/hmg/ddt336] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
It is a longstanding puzzle why non-coding variants in the complement factor H (CFH) gene are more strongly associated with age-related macular degeneration (AMD) than functional coding variants that directly influence the alternative complement pathway. The situation is complicated by tight genetic associations across the region, including the adjacent CFH-related genes CFHR3 and CFHR1, which may themselves influence the alternative complement pathway and are contained within a common deletion (CNP147) which is associated with protection against AMD. It is unclear whether this association is mediated through a protective effect of low plasma CFHR1 concentrations, high plasma CFH or both. We examined the triangular relationships of CFH/CFHR3/CFHR1 genotype, plasma CFH or CFHR1 concentrations and AMD susceptibility in combined case–control (1256 cases, 1020 controls) and cross-sectional population (n = 1004) studies and carried out genome-wide association studies of plasma CFH and CFHR1 concentrations. A non-coding CFH SNP (rs6677604) and the CNP147 deletion were strongly correlated both with each other and with plasma CFH and CFHR1 concentrations. The plasma CFH-raising rs6677604 allele and raised plasma CFH concentration were each associated with AMD protection. In contrast, the protective association of the CNP147 deletion with AMD was not mediated by low plasma CFHR1, since AMD-free controls showed increased plasma CFHR1 compared with cases, but it may be mediated by the association of CNP147 with raised plasma CFH concentration. The results are most consistent with a regulatory locus within a 32 kb region of the CFH gene, with a major effect on plasma CFH concentration and AMD susceptibility.
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Affiliation(s)
- Morad Ansari
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
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74
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Fan X, Yoshida Y, Honda S, Matsumoto M, Sawada Y, Hattori M, Hisanaga S, Hiwa R, Nakamura F, Tomomori M, Miyagawa S, Fujimaru R, Yamada H, Sawai T, Ikeda Y, Iwata N, Uemura O, Matsukuma E, Aizawa Y, Harada H, Wada H, Ishikawa E, Ashida A, Nangaku M, Miyata T, Fujimura Y. Analysis of genetic and predisposing factors in Japanese patients with atypical hemolytic uremic syndrome. Mol Immunol 2013; 54:238-46. [DOI: 10.1016/j.molimm.2012.12.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/09/2012] [Indexed: 11/24/2022]
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75
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Reiner AP, Hartiala J, Zeller T, Bis JC, Dupuis J, Fornage M, Baumert J, Kleber ME, Wild PS, Baldus S, Bielinski SJ, Fontes JD, Illig T, Keating BJ, Lange LA, Ojeda F, Müller-Nurasyid M, Munzel TF, Psaty BM, Rice K, Rotter JI, Schnabel RB, Tang WHW, Thorand B, Erdmann J, Jacobs DR, Wilson JG, Koenig W, Tracy RP, Blankenberg S, März W, Gross MD, Benjamin EJ, Hazen SL, Allayee H. Genome-wide and gene-centric analyses of circulating myeloperoxidase levels in the charge and care consortia. Hum Mol Genet 2013; 22:3381-93. [PMID: 23620142 DOI: 10.1093/hmg/ddt189] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Increased systemic levels of myeloperoxidase (MPO) are associated with the risk of coronary artery disease (CAD). To identify the genetic factors that are associated with circulating MPO levels, we carried out a genome-wide association study (GWAS) and a gene-centric analysis in subjects of European ancestry and African Americans (AAs). A locus on chromosome 1q31.1 containing the complement factor H (CFH) gene was strongly associated with serum MPO levels in 9305 subjects of European ancestry (lead SNP rs800292; P = 4.89 × 10(-41)) and in 1690 AA subjects (rs505102; P = 1.05 × 10(-8)). Gene-centric analyses in 8335 subjects of European ancestry additionally identified two rare MPO coding sequence variants that were associated with serum MPO levels (rs28730837, P = 5.21 × 10(-12); rs35897051, P = 3.32 × 10(-8)). A GWAS for plasma MPO levels in 9260 European ancestry subjects identified a chromosome 17q22 region near MPO that was significantly associated (lead SNP rs6503905; P = 2.94 × 10(-12)), but the CFH locus did not exhibit evidence of association with plasma MPO levels. Functional analyses revealed that rs800292 was associated with levels of complement proteins in serum. Variants at chromosome 17q22 also had pleiotropic cis effects on gene expression. In a case-control analysis of ∼80 000 subjects from CARDIoGRAM, none of the identified single-nucleotide polymorphisms (SNPs) were associated with CAD. These results suggest that distinct genetic factors regulate serum and plasma MPO levels, which may have relevance for various acute and chronic inflammatory disorders. The clinical implications for CAD and a better understanding of the functional basis for the association of CFH and MPO variants with circulating MPO levels require further study.
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76
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Complement dysregulation and disease: from genes and proteins to diagnostics and drugs. Immunobiology 2013; 217:1034-46. [PMID: 22964229 DOI: 10.1016/j.imbio.2012.07.021] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 07/20/2012] [Accepted: 07/21/2012] [Indexed: 12/21/2022]
Abstract
During the last decade, numerous studies have associated genetic variations in complement components and regulators with a number of chronic and infectious diseases. The functional characterization of these complement protein variants, in addition to recent structural advances in understanding of the assembly, activation and regulation of the AP C3 convertase, have provided important insights into the pathogenic mechanisms involved in some of these complement related disorders. This knowledge has identified potential targets for complement inhibitory therapies which are demonstrating efficacy and generating considerable expectation in changing the natural history of these diseases. Comprehensive understanding of the genetic and non-genetic risk factors contributing to these disorders will also result in targeting of the right patient groups in a stratified medicine approach through better diagnostics and individually tailored treatments, thereby improving management of patients.
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Yuan D, Yang Q, Liu X, Yuan D, Yuan S, Xie P, Liu Q. Complement factor H Val62Ile variant and risk of age-related macular degeneration: a meta-analysis. Mol Vis 2013; 19:374-83. [PMID: 23441108 PMCID: PMC3580987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 02/11/2013] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To evaluate the precise association of complement factor H (CFH) Val62Ile polymorphism with age-related macular degeneration (AMD) susceptibility. METHODS We performed a meta-analysis using databases including PubMed, EMBASE, and Web of Science to find relevant studies. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using fixed-effect and random-effects models. The inconsistency index (I(2)) was used to assess heterogeneity. Funnel plots and Egger's test were used to evaluate publication bias. Sensitivity analysis was also performed. RESULTS Fourteen studies including 4,438 patients with AMD and 6,099 controls based on the search criteria were involved in the meta-analysis. In overall populations, the pooled OR(1) for genotype GA+GG versus homozygous genotype AA was 2.28 (95% confidence interval (CI): 1.48-3.52), the OR(2) of heterozygous genotype GA versus AA was 1.58 (95% CI: 1.13-2.19), the OR(3) of homozygous genotype GG versus AA was 2.90 (95% CI: 1.95-4.30), and the OR(4) of allele G versus A was 1.77 (95% CI: 1.43-2.21). In Asian populations, our results provided substantial evidence that the Val62Ile variant was significantly associated with AMD (OR(4) = 1.85, 95% CI: 1.63-2.09). However, in Caucasian populations, no significant association of Val62Ile with AMD was established in all circumstances. CONCLUSIONS Our analysis provides substantial evidence that the Val62Ile variant is significantly associated with AMD in Asian populations. However, our results have demonstrated no link between the Val62Ile polymorphism and AMD in Caucasian populations.
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Affiliation(s)
- Dongqing Yuan
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Qin Yang
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Xiaoyi Liu
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Donglan Yuan
- Department of Nuclear Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Songtao Yuan
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Ping Xie
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Qinghuai Liu
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
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78
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Paixão-Cavalcante D, López-Trascasa M, Skattum L, Giclas PC, Goodship TH, de Córdoba SR, Truedsson L, Morgan BP, Harris CL. Sensitive and specific assays for C3 nephritic factors clarify mechanisms underlying complement dysregulation. Kidney Int 2012; 82:1084-92. [PMID: 22854646 PMCID: PMC3608896 DOI: 10.1038/ki.2012.250] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
C3 nephritic factors are autoantibodies that prolong the half-life or prevent regulation of the alternative pathway C3 convertase, resulting in uncontrolled complement activation. They are strongly associated with renal disease but their role in pathogenesis remains controversial. Here we optimized and compared a panel of assays to identify and interrogate nephritic factor activities. Of 101 patients with histologic or clinically evident disease, 48 were positive in some or all assays. In the presence of properdin, binding of autoantibody was detected in 39 samples and convertase stabilization was detected in 36. Forty-two of 48 nephritic factors tested prevented convertase decay by factor H, and most of these by decay accelerating factor (28) and complement receptor 1 (34). Representative properdin-independent nephritic factors had no effect on C5 cleavage and terminal pathway activity, while properdin-dependent nephritic factors enhanced activity. Biacore analysis of four purified IgG samples confirmed resistance to decay and showed that properdin-independent nephritic factors increased convertase half-life over 50-fold, whereas properdin-dependent nephritic factors increased the half-life 10- to 20-fold and also increased activity of the C3 convertase up to 10-fold. Thus, our study provides a rational approach to detect and characterize nephritic factors in patients.
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79
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Harris CL, Heurich M, Rodriguez de Cordoba S, Morgan BP. The complotype: dictating risk for inflammation and infection. Trends Immunol 2012; 33:513-21. [PMID: 22749446 PMCID: PMC3460238 DOI: 10.1016/j.it.2012.06.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/02/2012] [Accepted: 06/04/2012] [Indexed: 12/19/2022]
Abstract
Complement is a key component of immune defence against infection; it potently drives inflammation at sites of pathology and is essential for killing of pathogens. Genetic linkage of common complement polymorphisms to disease has advanced the concept that subtle changes in complement activity significantly affect disease risk. Functional analyses of disease-linked polymorphic variants demonstrate that, although individual polymorphisms cause only small changes in activity, when combined, the aggregate effects are large. The inherited set of common variants, the complotype, thus has a major impact on susceptibility to inflammatory and infectious diseases. Assessing the complotype of an individual will aid prediction of disease risk and inform intervention to reduce or eliminate risk.
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Affiliation(s)
- Claire L Harris
- Institute of Infection and Immunity, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK.
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80
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Rich RL, Myszka DG. Survey of the 2009 commercial optical biosensor literature. J Mol Recognit 2012; 24:892-914. [PMID: 22038797 DOI: 10.1002/jmr.1138] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We took a different approach to reviewing the commercial biosensor literature this year by inviting 22 biosensor users to serve as a review committee. They set the criteria for what to expect in a publication and ultimately decided to use a pass/fail system for selecting which papers to include in this year's reference list. Of the 1514 publications in 2009 that reported using commercially available optical biosensor technology, only 20% passed their cutoff. The most common criticism the reviewers had with the literature was that "the biosensor experiments could have been done better." They selected 10 papers to highlight good experimental technique, data presentation, and unique applications of the technology. This communal review process was educational for everyone involved and one we will not soon forget.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT, USA
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81
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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] [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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82
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Gibson J, Hakobyan S, Cree AJ, Collins A, Harris CL, Ennis S, Morgan BP, Lotery AJ. Variation in complement component C1 inhibitor in age-related macular degeneration. Immunobiology 2012; 217:251-5. [PMID: 21852020 DOI: 10.1016/j.imbio.2011.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 06/23/2011] [Accepted: 07/17/2011] [Indexed: 10/18/2022]
Abstract
This study assessed variation in plasma levels of the complement regulatorC1 inhibitor (C1inh) in patients with age related macular degeneration (AMD) and controls. Plasma from391 AMD cases and 370 controls was assayed by rate nephelometry to determine C1inh protein levels. Protein levels were analysed for relationships with age, gender, smoking, AMD disease status and genetic variation in the SERPING1 gene, which encodes C1inh, using a multivariate analysis. t-Tests show a significant difference in C1inh levels in AMD cases compared with controls (p=2.340E-6), smokers compared to non-smokers (p=1.022E-4) and females compared to males (p=1.661E-7). Multivariate analysis shows that after accounting for gender and smoking AMD status remained significant. Age was included in the model but was not significant. Including genetic variation in the model shows that one significant SNP (rs2649663) 5' of the SERPING1 gene is associated with C1inh levels though this SNP is not associated with AMD. This suggests that genetic variation in the promoter region of the SERPING1 gene may influence expression of the gene.
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Affiliation(s)
- J Gibson
- Genetic Epidemiology & Bioinformatics Group, Human Genetics Division, School of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
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83
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A novel hybrid CFH/CFHR3 gene generated by a microhomology-mediated deletion in familial atypical hemolytic uremic syndrome. Blood 2012; 119:591-601. [DOI: 10.1182/blood-2011-03-339903] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Genomic disorders affecting the genes encoding factor H (fH) and the 5 factor H related proteins have been described in association with atypical hemolytic uremic syndrome. These include deletions of CFHR3, CFHR1, and CFHR4 in association with fH autoantibodies and the formation of a hybrid CFH/CFHR1 gene. These occur through nonallelic homologous recombination secondary to the presence of large segmental duplications (macrohomology) in this region. Using multiplex ligation-dependent probe amplification to screen for such genomic disorders, we have identified a large atypical hemolytic uremic syndrome family where a deletion has occurred through microhomology-mediated end joining rather than nonallelic homologous recombination. In the 3 affected persons of this family, we have shown that the deletion results in formation of a CFH/CFHR3 gene. We have shown that the protein product of this is a 24 SCR protein that is secreted with normal fluid-phase activity but marked loss of complement regulation at cell surfaces despite increased heparin binding. In this study, we have therefore shown that microhomology in this area of chromosome 1 predisposes to disease associated genomic disorders and that the complement regulatory function of fH at the cell surface is critically dependent on the structural integrity of the whole molecule.
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84
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Jönsen A, Nilsson SC, Ahlqvist E, Svenungsson E, Gunnarsson I, Eriksson KG, Bengtsson A, Zickert A, Eloranta ML, Truedsson L, Rönnblom L, Nordmark G, Sturfelt G, Blom AM. Mutations in genes encoding complement inhibitors CD46 and CFH affect the age at nephritis onset in patients with systemic lupus erythematosus. Arthritis Res Ther 2011; 13:R206. [PMID: 22171659 PMCID: PMC3334659 DOI: 10.1186/ar3539] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/14/2011] [Accepted: 12/15/2011] [Indexed: 12/18/2022] Open
Abstract
Introduction Inherited deficiencies of several complement components strongly predispose to systemic lupus erythematosus (SLE) while deficiencies of complement inhibitors are found in kidney diseases such as atypical hemolytic uremic syndrome (aHUS). Methods The exons of complement inhibitor genes CD46 and CFH (factor H) were fully sequenced using the Sanger method in SLE patients with nephritis originating from two cohorts from southern and mid Sweden (n = 196). All identified mutations and polymorphisms were then analyzed in SLE patients without nephritis (n = 326) and in healthy controls (n = 523). Results We found nonsynonymous, heterozygous mutations in CFH in 6.1% patients with nephritis, in comparison with 4.0% and 5.4% in patients without nephritis and controls, respectively. No associations of SLE or nephritis with common variants in CFH (V62I/Y402H/E936D) were found. Furthermore, we found two nonsynonymous heterozygous mutations in CD46 in SLE patients but not in controls. The A353V polymorphism, known to affect function of CD46, was found in 6.6% of nephritis patients versus 4.9% and 6.1% of the non-nephritis SLE patients and controls. The presence of mutations in CD46 and CFH did not predispose to SLE or nephritis but was associated with earlier onset of nephritis. Furthermore, we found weak indications that there is one protective and one risk haplotype predisposing to nephritis composed of several polymorphisms in noncoding regions of CD46, which were previously implicated in aHUS. Conclusions SLE nephritis is not associated with frequent mutations in CFH and CD46 as found in aHUS but these may be modifying factors causing earlier onset of nephritis.
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Affiliation(s)
- Andreas Jönsen
- Section of Rheumatology, Department of Clinical Sciences Lund, Lund University, Kioskgatan 3, SE-221 85 Lund, Sweden
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85
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A rare variant in CFH directly links age-related macular degeneration with rare glomerular nephropathies. Nat Genet 2011; 43:1176-7. [PMID: 22120053 DOI: 10.1038/ng.1012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A careful analysis of risk haplotypes in relation to age-related macular degeneration (AMD) susceptibility has led to the identification of a rare, high-penetrance variant in the complement factor H (CFH) gene that is also causally associated with atypical hemolytic uremic syndrome (aHUS) and related glomerulopathies. This finding provides a convincing causal mechanism linking the two diseases and develops a paradigm for the genetic architecture of a common and complex disease.
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86
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Woehrl B, Brouwer MC, Murr C, Heckenberg SGB, Baas F, Pfister HW, Zwinderman AH, Morgan BP, Barnum SR, van der Ende A, Koedel U, van de Beek D. Complement component 5 contributes to poor disease outcome in humans and mice with pneumococcal meningitis. J Clin Invest 2011; 121:3943-53. [PMID: 21926466 DOI: 10.1172/jci57522] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 08/03/2011] [Indexed: 01/05/2023] Open
Abstract
Pneumococcal meningitis is the most common and severe form of bacterial meningitis. Fatality rates are substantial, and long-term sequelae develop in about half of survivors. Disease outcome has been related to the severity of the proinflammatory response in the subarachnoid space. The complement system, which mediates key inflammatory processes, has been implicated as a modulator of pneumococcal meningitis disease severity in animal studies. Additionally, SNPs in genes encoding complement pathway proteins have been linked to susceptibility to pneumococcal infection, although no associations with disease severity or outcome have been established. Here, we have performed a robust prospective nationwide genetic association study in patients with bacterial meningitis and found that a common nonsynonymous complement component 5 (C5) SNP (rs17611) is associated with unfavorable disease outcome. C5 fragment levels in cerebrospinal fluid (CSF) of patients with bacterial meningitis correlated with several clinical indicators of poor prognosis. Consistent with these human data, C5a receptor-deficient mice with pneumococcal meningitis had lower CSF wbc counts and decreased brain damage compared with WT mice. Adjuvant treatment with C5-specific monoclonal antibodies prevented death in all mice with pneumococcal meningitis. Thus, our results suggest C5-specific monoclonal antibodies could be a promising new antiinflammatory adjuvant therapy for pneumococcal meningitis.
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Affiliation(s)
- Bianca Woehrl
- Department of Neurology, Klinikum Grosshadern, Ludwig Maximilians University, Munich, Germany
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87
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Tortajada A, Pinto S, Martínez-Ara J, López-Trascasa M, Sánchez-Corral P, de Córdoba SR. Complement factor H variants I890 and L1007 while commonly associated with atypical hemolytic uremic syndrome are polymorphisms with no functional significance. Kidney Int 2011; 81:56-63. [PMID: 21881555 DOI: 10.1038/ki.2011.291] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mutations and polymorphisms in the gene-encoding factor H (CFH) are associated with atypical hemolytic uremic syndrome, dense deposit disease, and age-related macular degeneration. Many of these CFH genetic variations disrupt the regulatory role of factor H, supporting the concept that dysregulation of complement is a unifying pathogenic feature of these disorders. Evidence of a causal relationship with the disease is, however, not available for all CFH genetic variations found in patients, which is a potential cause of misinterpretations with important consequences for the patients and their relatives. CFH I890 and L1007 are two genetic variations repeatedly associated with atypical hemolytic uremic syndrome and also found in patients with dense deposit disease and age-related macular degeneration. Here we report an extensive genetic and functional analysis of these CFH variants. Our results indicate that I890 and L1007 segregate together as part of a distinct and relatively infrequent CFH haplotype in Caucasians. Extensive analysis of the S890/V1007 (control) and I890/L1007 (disease-associated) factor H protein variants failed to provide evidence that these amino acid changes have functional implications. Thus, the presence of the I890 and L1007 variants in healthy individuals and their high frequency in sub-Saharan African and African-American populations strongly suggest that I890 and L1007 are rare factor H polymorphisms unrelated to disease.
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Affiliation(s)
- Agustín Tortajada
- Departamento de Medicina Celular y Molecular, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, Madrid, Spain
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88
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Copy number variation in the complement factor H-related genes and age-related macular degeneration. Mol Vis 2011; 17:2080-92. [PMID: 21850184 PMCID: PMC3156785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 08/03/2011] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To determine the contribution of copy number variation (CNV) in the regulation of complement activation (RCA) locus to the development of age-related macular degeneration (AMD). METHODS A multiplex ligation-dependent probe amplification assay was developed to quantify the number of copies of CFH, CFHR3, CFHR1, CFHR4, CFHR2, and CFHR5 in humans. Subjects with (451) and without (362) AMD were genotyped using the assay, and the impact on AMD risk was evaluated. RESULTS Eight unique combinations of copy number variation were observed in the 813 subjects. Combined deletion of CFHR3 and CFHR1 was protective (OR=0.47, 95% confidence interval 0.36-0.62) against AMD and was observed in 88 (82 [18.6%] with one deletion, 6 [1.4%] with two deletions) subjects with AMD and 127 (108 [30.7%] with one deletion, 19 [5.4%] with two deletions) subjects without AMD. Other deletions were much less common: CFH intron 1 (n=2), CFH exon 18 (n=2), combined CFH exon 18 and CFHR3 (n=1), CFHR3 (n=2), CFHR1 (n=1), combined CFHR1 and CFHR4 (n=15), and CFHR2 deletion (n=7, 0.9%). The combined CFHR3 and CFHR1 deletion was observed on a common protective haplotype, while the others appeared to have arisen on multiple different haplotypes. CONCLUSIONS We found copy number variations of CFHR3, CFHR1, CFHR4, and CFHR2. Combined deletion of CFHR3 and CFHR1 was associated with a decreased risk of developing AMD. Other deletions were not sufficiently common to have a statistically detectable impact on the risk of AMD, and duplications were not observed.
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89
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Khandhadia S, Cipriani V, Yates JRW, Lotery AJ. Age-related macular degeneration and the complement system. Immunobiology 2011; 217:127-46. [PMID: 21868123 DOI: 10.1016/j.imbio.2011.07.019] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 06/22/2011] [Accepted: 07/18/2011] [Indexed: 11/30/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world. It is a complex multifactorial disease, and despite new advances in treatment, many patients still succumb to visual impairment. The complement pathway has been implicated in the pathogenesis of many diseases, and recently variants in several genes encoding complement pathway proteins have been associated with AMD. Complement proteins have been found in histological specimens of eyes with AMD. Altered levels of both intrinsic complement proteins and activated products have been found in the circulation of patients with AMD. Complement activation may be triggered by oxidative stress, resulting from retinal exposure to incoming light; indeed an inter-play between these two pathological processes seems to exist. Finally, complement inhibitors are currently being evaluated in clinical trials. This article reviews the role of the complement system in AMD, and the potential of complement inhibition in preventing the devastating blindness resulting from this disease.
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Affiliation(s)
- S Khandhadia
- Clinical Neurosciences Division, University of Southampton, UK
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90
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Abrera-Abeleda MA, Nishimura C, Frees K, Jones M, Maga T, Katz LM, Zhang Y, Smith RJH. Allelic variants of complement genes associated with dense deposit disease. J Am Soc Nephrol 2011; 22:1551-9. [PMID: 21784901 DOI: 10.1681/asn.2010080795] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The alternative pathway of the complement cascade plays a role in the pathogenesis of dense deposit disease (DDD). Deficiency of complement factor H and mutations in CFH associate with the development of DDD, but it is unknown whether allelic variants in other complement genes also associate with this disease. We studied patients with DDD and identified previously unreported sequence alterations in several genes in addition to allelic variants and haplotypes common to patients with DDD. We found that the likelihood of developing DDD increases with the presence of two or more risk alleles in CFH and C3. To determine the functional consequence of this finding, we measured the activity of the alternative pathway in serum samples from phenotypically normal controls genotyped for variants in CFH and C3. Alternative pathway activity was higher in the presence of variants associated with DDD. Taken together, these data confirm that DDD is a complex genetic disease and may provide targets for the development of disease-specific therapies.
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91
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Zhao J, Wu H, Khosravi M, Cui H, Qian X, Kelly JA, Kaufman KM, Langefeld CD, Williams AH, Comeau ME, Ziegler JT, Marion MC, Adler A, Glenn SB, Alarcón-Riquelme ME, Pons-Estel BA, Harley JB, Bae SC, Bang SY, Cho SK, Jacob CO, Vyse TJ, Niewold TB, Gaffney PM, Moser KL, Kimberly RP, Edberg JC, Brown EE, Alarcon GS, Petri MA, Ramsey-Goldman R, Vilá LM, Reveille JD, James JA, Gilkeson GS, Kamen DL, Freedman BI, Anaya JM, Merrill JT, Criswell LA, Scofield RH, Stevens AM, Guthridge JM, Chang DM, Song YW, Park JA, Lee EY, Boackle SA, Grossman JM, Hahn BH, Goodship THJ, Cantor RM, Yu CY, Shen N, Tsao BP. Association of genetic variants in complement factor H and factor H-related genes with systemic lupus erythematosus susceptibility. PLoS Genet 2011; 7:e1002079. [PMID: 21637784 PMCID: PMC3102741 DOI: 10.1371/journal.pgen.1002079] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 03/28/2011] [Indexed: 01/24/2023] Open
Abstract
Systemic lupus erythematosus (SLE), a complex polygenic autoimmune disease, is associated with increased complement activation. Variants of genes encoding complement regulator factor H (CFH) and five CFH-related proteins (CFHR1-CFHR5) within the chromosome 1q32 locus linked to SLE, have been associated with multiple human diseases and may contribute to dysregulated complement activation predisposing to SLE. We assessed 60 SNPs covering the CFH-CFHRs region for association with SLE in 15,864 case-control subjects derived from four ethnic groups. Significant allelic associations with SLE were detected in European Americans (EA) and African Americans (AA), which could be attributed to an intronic CFH SNP (rs6677604, in intron 11, Pmeta = 6.6×10−8, OR = 1.18) and an intergenic SNP between CFHR1 and CFHR4 (rs16840639, Pmeta = 2.9×10−7, OR = 1.17) rather than to previously identified disease-associated CFH exonic SNPs, including I62V, Y402H, A474A, and D936E. In addition, allelic association of rs6677604 with SLE was subsequently confirmed in Asians (AS). Haplotype analysis revealed that the underlying causal variant, tagged by rs6677604 and rs16840639, was localized to a ∼146 kb block extending from intron 9 of CFH to downstream of CFHR1. Within this block, the deletion of CFHR3 and CFHR1 (CFHR3-1Δ), a likely causal variant measured using multiplex ligation-dependent probe amplification, was tagged by rs6677604 in EA and AS and rs16840639 in AA, respectively. Deduced from genotypic associations of tag SNPs in EA, AA, and AS, homozygous deletion of CFHR3-1Δ (Pmeta = 3.2×10−7, OR = 1.47) conferred a higher risk of SLE than heterozygous deletion (Pmeta = 3.5×10−4, OR = 1.14). These results suggested that the CFHR3-1Δ deletion within the SLE-associated block, but not the previously described exonic SNPs of CFH, might contribute to the development of SLE in EA, AA, and AS, providing new insights into the role of complement regulators in the pathogenesis of SLE. Systemic lupus erythematosus (SLE) is a complex autoimmune disease, associated with increased complement activation. Previous studies have provided evidence for the presence of SLE susceptibility gene(s) in the chromosome 1q31-32 locus. Within 1q32, genes encoding complement regulator factor H (CFH) and five CFH-related proteins (CFHR1-CFHR5) may contribute to the development of SLE, because genetic variants of these genes impair complement regulation and predispose to various human diseases. In this study, we tested association of genetic variants in the region containing CFH and CFHRs with SLE. We identified genetic variants predisposing to SLE in European American, African American, and Asian populations, which might be attributed to the deletion of CFHR3 and CFHR1 genes but not previously identified disease-associated exonic variants of CFH. This study provides the first evidence for consistent association between CFH/CFHRs and SLE across multi-ancestral SLE datasets, providing new insights into the role of complement regulators in the pathogenesis of SLE.
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Affiliation(s)
- Jian Zhao
- Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Hui Wu
- Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Melanie Khosravi
- Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Huijuan Cui
- Joint Molecular Rheumatology Laboratory of Institute of Health Sciences and Shanghai Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institutes for Biological Sciences, and Chinese Academy of Sciences, Shanghai, China
| | - Xiaoxia Qian
- Joint Molecular Rheumatology Laboratory of Institute of Health Sciences and Shanghai Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institutes for Biological Sciences, and Chinese Academy of Sciences, Shanghai, China
| | - Jennifer A. Kelly
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Kenneth M. Kaufman
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- United States Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, United States of America
| | - Carl D. Langefeld
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Wake Forest, North Carolina, United States of America
| | - Adrienne H. Williams
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Wake Forest, North Carolina, United States of America
| | - Mary E. Comeau
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Wake Forest, North Carolina, United States of America
| | - Julie T. Ziegler
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Wake Forest, North Carolina, United States of America
| | - Miranda C. Marion
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Wake Forest, North Carolina, United States of America
| | - Adam Adler
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Stuart B. Glenn
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Marta E. Alarcón-Riquelme
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Center for Genomics and Oncological Research, Pfizer-University of Granada-Junta de Andalucia, Granada, Spain
| | | | | | | | - John B. Harley
- Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
- United States Department of Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America
| | - Sang-Cheol Bae
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea
| | - So-Young Bang
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea
| | - Soo-Kyung Cho
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea
| | - Chaim O. Jacob
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Timothy J. Vyse
- Divisions of Genetics and Molecular Medicine and Immunology, King's College London, London, United Kingdom
| | - Timothy B. Niewold
- Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, Illinois, United States of America
| | - Patrick M. Gaffney
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Kathy L. Moser
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Robert P. Kimberly
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jeffrey C. Edberg
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Elizabeth E. Brown
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Graciela S. Alarcon
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Michelle A. Petri
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Rosalind Ramsey-Goldman
- Division of Rheumatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Luis M. Vilá
- Division of Rheumatology, Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - John D. Reveille
- Rheumatology and Clinical Immunogenetics, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Judith A. James
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Gary S. Gilkeson
- Division of Rheumatology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Diane L. Kamen
- Division of Rheumatology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Barry I. Freedman
- Department of Internal Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina, United States of America
| | - Juan-Manuel Anaya
- Center for Autoimmune Disease Research, Universidad del Rosario, Bogota, Colombia
| | - Joan T. Merrill
- Clinical Pharmacology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Lindsey A. Criswell
- Rosalind Russell Medical Research Center for Arthritis, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - R. Hal Scofield
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- United States Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, United States of America
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Anne M. Stevens
- Division of Rheumatology, Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Joel M. Guthridge
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | | | - Yeong Wook Song
- Division of Rheumatology, Seoul National University, Seoul, Korea
| | - Ji Ah Park
- Division of Rheumatology, Seoul National University, Seoul, Korea
| | - Eun Young Lee
- Division of Rheumatology, Seoul National University, Seoul, Korea
| | - Susan A. Boackle
- Division of Rheumatology, School of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Jennifer M. Grossman
- Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Bevra H. Hahn
- Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | | | - Rita M. Cantor
- Department of Human Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Chack-Yung Yu
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
| | - Nan Shen
- Joint Molecular Rheumatology Laboratory of Institute of Health Sciences and Shanghai Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institutes for Biological Sciences, and Chinese Academy of Sciences, Shanghai, China
| | - Betty P. Tsao
- Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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92
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Smith RJH, Harris CL, Pickering MC. Dense deposit disease. Mol Immunol 2011; 48:1604-10. [PMID: 21601923 DOI: 10.1016/j.molimm.2011.04.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 04/05/2011] [Accepted: 04/06/2011] [Indexed: 02/06/2023]
Abstract
Dense deposit disease (DDD) is an orphan disease that primarily affects children and young adults without sexual predilection. Studies of its pathophysiology have shown conclusively that it is caused by fluid-phase dysregulation of the alternative pathway of complement, however the role played by genetics and autoantibodies like C3 nephritic factors must be more thoroughly defined if we are to make an impact in the clinical management of this disease. There are currently no mechanism-directed therapies to offer affected patients, half of whom progress to end stage renal failure disease within 10 years of diagnosis. Transplant recipients face the dim prospect of disease recurrence in their allografts, half of which ultimately fail. More detailed genetic and complement studies of DDD patients may make it possible to identify protective factors prognostic for naïve kidney and transplant survival, or conversely risk factors associated with progression to renal failure and allograft loss. The pathophysiology of DDD suggests that a number of different treatments warrant consideration. As advances are made in these areas, there will be a need to increase healthcare provider awareness of DDD by making resources available to clinicians to optimize care for DDD patients.
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Affiliation(s)
- Richard J H Smith
- Department of Internal Medicine, Division of Nephrology, Carver College of Medicine, University of Iowa, 21151 PFP, 200 Hawkins Drive, Iowa City, IA 52242, USA.
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93
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Common polymorphisms in C3, factor B, and factor H collaborate to determine systemic complement activity and disease risk. Proc Natl Acad Sci U S A 2011; 108:8761-6. [PMID: 21555552 DOI: 10.1073/pnas.1019338108] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Common polymorphisms in complement alternative pathway (AP) proteins C3 (C3(R102G)), factor B (fB(R32Q)), and factor H (fH(V62I)) are associated with age-related macular degeneration (AMD) and other pathologies. Our published work showed that fB(R32Q) influences C3 convertase formation, whereas fH(V62I) affects factor I cofactor activity. Here we show how C3(R102G) (C3S/F) influences AP activity. In hemolysis assays, C3(102G) activated AP more efficiently (EC(50) C3(102G): 157 nM; C3(102R): 191 nM; P < 0.0001). fB binding kinetics and convertase stability were identical, but native and recombinant fH bound more strongly to C3b(102R) (K(D) C3b(102R): 1.0 μM; C3b(102G): 1.4 μM; P < 0.0001). Accelerated decay was unaltered, but fH cofactor activity was reduced for C3b(102G), favoring AP amplification. Combining disease "risk" variants (C3(102G), fB(32R), and fH(62V)) in add-back assays yielded sixfold higher hemolytic activity compared with "protective" variants (C3(102R), fB(32Q), and fH(62I); P < 0.0001). These data introduce the concept of a functional complotype (combination of polymorphisms) defining complement activity in an individual, thereby influencing susceptibility to AP-driven disease.
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94
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Hughes AE, Mullan GM, Bradley DT. Complement factor B polymorphism 32W protects against age-related macular degeneration. Mol Vis 2011; 17:983-8. [PMID: 21541267 PMCID: PMC3084221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 04/16/2011] [Indexed: 11/19/2022] Open
Abstract
PURPOSE The 32Q (rs641153; A) and 32W (rs12614; T) variants of complement factor B (CFB) cause less efficient complement activation in vitro than the common 32R variant. This is thought to be the reason that the 32Q variant is associated with decreased risk of age-related macular degeneration (AMD). We investigated whether the 32W variant was also associated with decreased risk of AMD. METHODS We genotyped 367 cases with neovascular AMD and 251 disease-free controls. Association with the disease phenotype was assessed by logistic regression for polymorphisms of CFB alone and in combination with smoking status and genetic risk markers of complement factor H (CFH) and HtrA serine peptidase 1 (HTRA1). We performed meta-analysis of all previously published reports of 32W allele frequency in AMD cases and controls. RESULTS The CFB variant 32W was associated with protection against neovascular AMD, compared to the common 32R variant (odds ratio 0.64, p<0.05, in logistic regression with CFB variants; odds ratio 0.53, p<0.05, in logistic regression with CFB variants, CFH haplotypes, HTRA1 rs10490924 genotype, and smoking status). Meta-analysis (n=1,795) including this study and two others of neovascular AMD showed a combined odds ratio of 0.75 (p<0.05) for 32W, compared to 32R. Meta-analysis (n=2,600) of all reported studies of all types of AMD showed a combined odds ratio of 0.79 (p<0.01). CONCLUSIONS Our study shows that the 32W variant of CFB is associated with protection against AMD, in keeping with evidence of its functional effect on the complement system. The protective effect is less strong than that associated with 32Q.
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Affiliation(s)
- Anne E Hughes
- Centre for Public Health, Queen's University Belfast, UK.
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95
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Abstract
Age-related macular degeneration (AMD) is an inflammatory disease, which causes visual impairment and blindness in older people. The proteins of the complement system are central to the development of this disease. Local and systemic inflammation in AMD are mediated by the deregulated action of the alternative pathway of the complement system. Variants in complement system genes alter an individual's risk of developing AMD. Recent studies have shown how some risk-associated genetic variants alter the function of the complement system. In this review, we describe the evolution of the complement system and bring together recent research to form a picture of how changes in complement system genes and proteins affect the function of the complement cascade, and how this affects the development of AMD. We discuss the application of this knowledge to prevention and possible future treatments of AMD.
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96
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Pechtl IC, Kavanagh D, McIntosh N, Harris CL, Barlow PN. Disease-associated N-terminal complement factor H mutations perturb cofactor and decay-accelerating activities. J Biol Chem 2011; 286:11082-90. [PMID: 21270465 PMCID: PMC3064162 DOI: 10.1074/jbc.m110.211839] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many mutations associated with atypical hemolytic uremic syndrome (aHUS) lie within complement control protein modules 19-20 at the C terminus of the complement regulator factor H (FH). This region mediates preferential action of FH on self, as opposed to foreign, membranes and surfaces. Hence, speculation on disease mechanisms has focused on deficiencies in regulation of complement activation on glomerular capillary beds. Here, we investigate the consequences of aHUS-linked mutations (R53H and R78G) within the FH N-terminal complement control protein module that also carries the I62V variation linked to dense-deposit disease and age-related macular degeneration. This module contributes to a four-module C3b-binding site (FH1-4) needed for complement regulation and sufficient for fluid-phase regulatory activity. Recombinant FH1-4(V62) and FH1-4(I62) bind immobilized C3b with similar affinities (K(D) = 10-14 μM), whereas FH1-4(I62) is slightly more effective than FH1-4(V62) as cofactor for factor I-mediated cleavage of C3b. The mutant (R53H)FH1-4(V62) binds to C3b with comparable affinity (K(D) ∼12 μM) yet has decreased cofactor activities both in fluid phase and on surface-bound C3b, and exhibits only weak decay-accelerating activity for C3 convertase (C3bBb). The other mutant, (R78G)FH1-4(V62), binds poorly to immobilized C3b (K(D) >35 μM) and is severely functionally compromised, having decreased cofactor and decay-accelerating activities. Our data support causal links between these mutations and disease; they demonstrate that mutations affecting the N-terminal activities of FH, not just those in the C terminus, can predispose to aHUS. These observations reinforce the notion that deficiency in any one of several FH functional properties can contribute to the pathogenesis of this disease.
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Affiliation(s)
- Isabell C Pechtl
- School of Chemistry, University of Edinburgh, Edinburgh, Scotland, United Kingdom
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97
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Roumenina LT, Loirat C, Dragon-Durey MA, Halbwachs-Mecarelli L, Sautes-Fridman C, Fremeaux-Bacchi V. Alternative complement pathway assessment in patients with atypical HUS. J Immunol Methods 2011; 365:8-26. [PMID: 21215749 DOI: 10.1016/j.jim.2010.12.020] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/31/2010] [Accepted: 12/30/2010] [Indexed: 01/02/2023]
Abstract
The atypical Hemolytic Uremic Syndrome (aHUS) is a rare thrombotic microangiopathy leading to end stage renal disease in approximately 60% of patients. Over the last decade, a clear link has been demonstrated between this disease and defective complement regulation. The hallmark of the aHUS is the association with mutations in complement alternative pathway genes. Endothelial damage is related to complement dysregulation, but the exact mechanism is just starting to be elucidated. Screening for and characterization of mutations in the components of the C3 convertase (C3 and FB) or its regulators (FH, FI, MCP, and Thrombomodulin) or anti-FH antibodies has become an indispensable part of the disease's diagnostic. This review will initially summarize current knowledge on the understanding of complement activation and regulation, followed by a description on the genetic analysis as well as the methods used for complement protein quantification. Another part of this review will focus on the mechanisms of action of aHUS-associated mutations. We will emphasize on when and why some mutations lead to protein deficiency, while others result in - to dysfunctional but normally expressed proteins. Finally, we will discuss how the therapy of aHUS patients can be modified according to the functional consequences of each particular genetic defect.
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The significance of the complement system for the pathogenesis of age-related macular degeneration - current evidence and translation into clinical application. Graefes Arch Clin Exp Ophthalmol 2010; 249:163-74. [PMID: 21127893 PMCID: PMC3042099 DOI: 10.1007/s00417-010-1568-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 10/25/2010] [Accepted: 10/29/2010] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Dysregulation of the complement system has been shown to play a major role in the pathogenesis of age-related macular degeneration (AMD). METHODS The current evidence from human studies derives from immunohistochemical and proteomic studies in donor eyes, genetic association studies, and studies of blood complement protein levels. These lines of evidence are corroborated by in vitro and animal studies. RESULTS In AMD donor eyes, detection of complement proteins in drusen suggested local inflammatory processes involving the complement system. Moreover, higher levels of complement proteins in the Bruch's membrane/choroid complex could be detected in AMD donor eyes compared to controls. A large number of independent genetic studies have consistently confirmed the association of AMD with risk or protective variants in genes coding for complement proteins, including complement factor H (CFH), CFH-related proteins 1 and 3, factor B/C2, C3 and factor I. Another set of independent studies detected increased levels of complement activation products in plasma of AMD patients, suggesting that AMD may be a systemic disease and the macula a vulnerable anatomic site of minimal resistance to complement activation. Genotype-phenotype correlations, including the impact of genetic variants on disease progression, gene-environment and pharmacogenetic interactions, have been investigated. There is evidence that complement gene variants may be associated with the progression from early to late forms of AMD, whereas they do not appear to play a significant role when late atrophic AMD has already developed. There are indications for an interaction between genetic variants and supplementation and dietary factors. Also, there is some evidence that variants in the CFH gene influence treatment effects in patients with neovascular AMD. CONCLUSIONS Such data suggest that the complement system may have a significant role for developing new prophylactic and therapeutic interventions in AMD. In fact, several compounds acting on the complement pathway are currently in clinical trials. Therapeutics that modulate the complement system need to balance inhibition with preservation of sufficient functional activity in order to maintain adequate immune responses and tissue homeostasis. Specifically, targeting the dysfunction appears more adequate than a global suppression of complement activation in chronic diseases such as AMD.
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Abstract
Central to the pathogenesis of atypical hemolytic uremic syndrome (aHUS) is over-activation of the alternative pathway of complement. Following the initial discovery of mutations in the complement regulatory protein, factor H, mutations have been described in factor I, membrane cofactor protein and thrombomodulin, which also result in decreased complement regulation. Autoantibodies to factor H have also been reported to impair complement regulation in aHUS. More recently, gain of function mutations in the complement components C3 and Factor B have been seen. This review focuses on the genetic causes of aHUS, their functional consequences, and clinical effect.
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Rodríguez de Córdoba S, Harris CL, Morgan BP, Llorca O. Lessons from functional and structural analyses of disease-associated genetic variants in the complement alternative pathway. Biochim Biophys Acta Mol Basis Dis 2010; 1812:12-22. [PMID: 20837143 DOI: 10.1016/j.bbadis.2010.09.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 09/03/2010] [Accepted: 09/07/2010] [Indexed: 11/15/2022]
Abstract
Complement is an essential component of innate immunity and a major trigger of inflammatory responses. A critical step in complement activation is the formation of the C3 convertase of the alternative pathway (AP), a labile bimolecular complex formed by activated fragments of the C3 and factor B components that is fundamental to provide exponential amplification of the initial complement trigger. Regulation of the AP C3 convertase is essential to maintain complement homeostasis in plasma and to protect host cells and tissues from damage by complement. During the last decade, several studies have associated genetic variations in components and regulators of the AP C3 convertase with a number of chronic inflammatory diseases and susceptibility to infection. The functional characterization of these protein variants has helped to decipher the critical pathogenic mechanisms involved in some of these complement related disorders. In addition, these functional data together with recent 3D structures of the AP C3 convertase have provided fundamental insights into the assembly, activation and regulation of the AP C3 convertase.
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Affiliation(s)
- Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain.
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